1
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Zhang S, Zeng Y, Liu R, Liu X, Xue Y. Impact of varying dissolved organic carbon load on sediment phosphorus release and its periodic mechanisms. ENVIRONMENTAL RESEARCH 2024; 259:119558. [PMID: 38969317 DOI: 10.1016/j.envres.2024.119558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
Phosphorus (P) release from sediment poses a severe challenge for eutrophication management in the aquatic environment. The dissolved organic carbon (DOC) concentrations in riverine ecosystems have shown an increasing trend due to intensified climate change and anthropogenic activities, while their impact on sediment P cycling remains unclear. To investigate the effects of different DOC loads on sediment P release and the underlying mechanisms, we conducted a two-month experiment in 15 plexiglass tanks, with five gradient-increasing target DOC concentrations set according to reality: control (S0), 5 mg/L (S5), 10 mg/L (S10), 15 mg/L (S15), and 20 mg/L (S20). The results demonstrated that: i) DOC enrichment promoted the sediment P mobilization and release, with the underlying mechanisms exhibited periodic characteristics. ii) reduced dissolved oxygen (DO) concentration and stimulated alkaline phosphatase activity (APA) were likely the primary and sustained facilitating mechanisms. While after the termination of DOC load, elevated pH level was also considered a contributing factor when chlorophyll a (Chl a) ranged between 5.9 μg/L and 7.7 μg/L iii) ultimate concentration of total P (TP) in the overlying water depended on DOC load. After DOC addition was terminated, decreased TP concentrations were observed when DOC concentration was in the range of 5-15 mg/L, which may be attributed to the direct uptake of P by phytoplankton counteracting the minor promotion of P release induced by anoxic conditions. However, when DOC concentrations exceeded 15-20 mg/L, there were notable increments in TP concentrations. Our findings provide further insight into the response mechanisms of sediment P release to the increasing organic C load in natural ecosystems. The impact of broader C forms or C loads on sediment P cycling needs to be fully elucidated and even quantified in future studies, especially through large-scale field investigations to further clarify the coupled roles between C and P.
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Affiliation(s)
- Shiyao Zhang
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China
| | - Yuhong Zeng
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China.
| | - Runpei Liu
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China
| | - Xiaoning Liu
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China
| | - Yingwen Xue
- School of Civil Engineering, Wuhan University, Wuhan, 430072, China
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2
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Paltsev A, Bergström AK, Vuorio K, Creed IF, Hessen DO, Kortelainen P, Vuorenmaa J, de Wit HA, Lau DCP, Vrede T, Isles PDF, Jonsson A, Geibrink E, Kahilainen KK, Drakare S. Phytoplankton biomass in northern lakes reveals a complex response to global change. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 940:173570. [PMID: 38825201 DOI: 10.1016/j.scitotenv.2024.173570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/25/2024] [Accepted: 05/25/2024] [Indexed: 06/04/2024]
Abstract
Global change may introduce fundamental alterations in phytoplankton biomass and community structure that can alter the productivity of northern lakes. In this study, we utilized Swedish and Finnish monitoring data from lakes that are spatially (135 lakes) and temporally (1995-2019, 110 lakes) extensive to assess how phytoplankton biomass (PB) of dominant phytoplankton groups related to changes in water temperature, pH and key nutrients [total phosphorus (TP), total nitrogen (TN), total organic carbon (TOC), iron (Fe)] along spatial (Fennoscandia) and temporal (25 years) gradients. Using a machine learning approach, we found that TP was the most important determinant of total PB and biomass of a specific species of Raphidophyceae - Gonyostomum semen - and Cyanobacteria (both typically with adverse impacts on food-webs and water quality) in spatial analyses, while Fe and pH were second in importance for G. semen and TN and pH were second and third in importance for Cyanobacteria. However, in temporal analyses, decreasing Fe and increasing pH and TOC were associated with a decrease in G. semen and an increase in Cyanobacteria. In addition, in many lakes increasing TOC seemed to have generated browning to an extent that significantly reduced PB. The identified discrepancy between the spatial and temporal results suggests that substitutions of data for space-for-time may not be adequate to characterize long-term effects of global change on phytoplankton. Further, we found that total PB exhibited contrasting temporal trends (increasing in northern- and decreasing in southern Fennoscandia), with the decline in total PB being more pronounced than the increase. Among phytoplankton, G. semen biomass showed the strongest decline, while cyanobacterial biomass showed the strongest increase over 25 years. Our findings suggest that progressing browning and changes in Fe and pH promote significant temporal changes in PB and shifts in phytoplankton community structures in northern lakes.
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Affiliation(s)
- Aleksey Paltsev
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.
| | | | | | - Irena F Creed
- Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Dag Olav Hessen
- Centre of Biogeochemistry in the Anthropocene and Department of Bioscience, University of Oslo, Oslo, Norway
| | | | | | - Heleen A de Wit
- Centre of Biogeochemistry in the Anthropocene and Department of Bioscience, University of Oslo, Oslo, Norway; Norwegian Institute for Water Research, Oslo, Norway
| | - Danny C P Lau
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tobias Vrede
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Peter D F Isles
- Watershed Management Division, Vermont Department of Environmental Conservation, Montpelier, VT, USA
| | - Anders Jonsson
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Erik Geibrink
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | | | - Stina Drakare
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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3
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Schultze S, Langva HK, Wei J, Chatzigeorgiou M, Rundberget JT, Hessen DO, Ruus A, Andersen T, Borgå K. Do DOM quality and origin affect the uptake and accumulation of a lipid-soluble contaminant in a filter feeding ascidian species (Ciona) that can target small particle size classes? AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 273:107026. [PMID: 39059104 DOI: 10.1016/j.aquatox.2024.107026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 06/30/2024] [Accepted: 07/13/2024] [Indexed: 07/28/2024]
Abstract
The widely reported increase of terrestrial dissolved organic matter (terrDOM) in northern latitude coastal areas ("coastal darkening") can impact contaminant dynamics in affected systems. One potential impact is based on differences in chemical adsorption processes of the molecularly larger terrDOM compared to marine DOM (marDOM) that leads to increased emulsification of lipophilic contaminants with terrDOM. Filter feeders filter large amounts of water and DOM daily and thus are directly exposed to associated contaminants through both respiration and feeding activity. Thus, increased exposure to terrDOM could potentially lead to an increase in bioaccumulation of lipid soluble contaminants in filter feeders. To assess the effect of DOM on bioaccumulation in filter feeders, we exposed the mucous based filter feeding ascidian Ciona intestinalis (formerly known as Ciona intestinalis Type B), to the lipophilic veterinary drug teflubenzuron (log KOW: 5.39) in combination with four DOM treatments: TerrDOM, marDOM, a mix of the two called mixDOM, and seawater without DOM addition. The exposure lasted for 15 days, after which the individuals in all DOM treatments showed a trend towards higher bioaccumulation of Teflubenzuron than those in the seawater control. However, there was considerable overlap in posterior distributions. Against our expectations, marDOM resulted in the highest bioaccumulation factor (BAF), followed by mixDOM, with terrDOM resulting in the lowest BAF except for seawater (kinetic BAF L/kg median, 2.5 %-97.5 % percentile marDOM 94, 74-118; mixDOM 82, 63-104; terrDOM 79; 61-99; seawater 61, 44-79). All BAFs were below the level of concern according to the EU REACH regulation (BAF < 2000 L / kg) and, therefore, likely not environmentally problematic in the examined context. However, the results show that DOM can act as a dietary vector; thus, different combinations of contaminants, DOM, and filter feeding organisms should be tested further.
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Affiliation(s)
- Sabrina Schultze
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway.
| | - Hilde K Langva
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | - Jing Wei
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | | | - Jan T Rundberget
- Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway
| | - Dag O Hessen
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | - Anders Ruus
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway; Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway
| | - Tom Andersen
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | - Katrine Borgå
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
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4
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Swinamer R, Anderson LE, Redden D, Bjorndahl P, Campbell J, Krkošek WH, Gagnon GA. Climate-Driven Increases in Source Water Natural Organic Matter: Implications for the Sustainability of Drinking Water Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11958-11969. [PMID: 38922292 PMCID: PMC11238540 DOI: 10.1021/acs.est.4c01894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 06/27/2024]
Abstract
This study presents an updated analysis spanning over two decades (1999-2023) of climate, water quality, and operational data from two drinking water facilities in Atlantic Canada that previously experienced gradual increases in the natural organic matter (NOM) concentration and brownification. The goal was to assess the impact of recent extreme weather events on acute NOM concentration increases and drinking water treatment processes. In 2023, a dry spring combined with a warm and wet summer caused NOM in the water supplies to increase by >67% (as measured by color). To mitigate increased NOM concentration, the alum dose nearly doubled in 2023 compared to that in 2022. Disinfection byproducts were elevated following the event but remained within the compliance levels. From 1999 to 2023, the two plants responded to gradual climate change impacts and brownification, with alum dose increases of between 4.1 and 8.3 times. Equivalent CO2 emissions were estimated for alum usage, which increased by 3 to 7-fold in 2023 compared to when the plants were commissioned decades prior. The plants were not only adversely impacted by climate change but also contributed to the global CO2 burden. Thus, a paradigm shift toward sustainable alternatives for NOM removal is required in the water sector, and climate change adaptation and mitigation principles are urgently needed.
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Affiliation(s)
- Ryan Swinamer
- Centre
for Water Resources Studies, Faculty of Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lindsay E. Anderson
- Centre
for Water Resources Studies, Faculty of Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia B3H 4R2, Canada
| | - Dave Redden
- Centre
for Water Resources Studies, Faculty of Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia B3H 4R2, Canada
| | - Paul Bjorndahl
- Department
of Mathematics & Statistics, Dalhousie
University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jessica Campbell
- Halifax
Water, 450 Cowie Hill
Road, Halifax, Nova Scotia B3P 2 V3, Canada
| | - Wendy H. Krkošek
- Halifax
Water, 450 Cowie Hill
Road, Halifax, Nova Scotia B3P 2 V3, Canada
| | - Graham A. Gagnon
- Centre
for Water Resources Studies, Faculty of Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia B3H 4R2, Canada
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5
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Muhlfeld CC, Cline TJ, Finstad AG, Hessen DO, Perrin S, Thaulow J, Whited D, Vøllestad LA. Climate change vulnerability of Arctic char across Scandinavia. GLOBAL CHANGE BIOLOGY 2024; 30:e17387. [PMID: 38971982 DOI: 10.1111/gcb.17387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/08/2024] [Accepted: 05/21/2024] [Indexed: 07/08/2024]
Abstract
Climate change is anticipated to cause species to shift their ranges upward and poleward, yet space for tracking suitable habitat conditions may be limited for range-restricted species at the highest elevations and latitudes of the globe. Consequently, range-restricted species inhabiting Arctic freshwater ecosystems, where global warming is most pronounced, face the challenge of coping with changing abiotic and biotic conditions or risk extinction. Here, we use an extensive fish community and environmental dataset for 1762 lakes sampled across Scandinavia (mid-1990s) to evaluate the climate vulnerability of Arctic char (Salvelinus alpinus), the world's most cold-adapted and northernly distributed freshwater fish. Machine learning models show that abiotic and biotic factors strongly predict the occurrence of Arctic char across the region with an overall accuracy of 89 percent. Arctic char is less likely to occur in lakes with warm summer temperatures, high dissolved organic carbon levels (i.e., browning), and presence of northern pike (Esox lucius). Importantly, climate warming impacts are moderated by habitat (i.e., lake area) and amplified by the presence of competitors and/or predators (i.e., northern pike). Climate warming projections under the RCP8.5 emission scenario indicate that 81% of extant populations are at high risk of extirpation by 2080. Highly vulnerable populations occur across their range, particularly near the southern range limit and at lower elevations, with potential refugia found in some mountainous and coastal regions. Our findings highlight that range shifts may give way to range contractions for this cold-water specialist, indicating the need for pro-active conservation and mitigation efforts to avoid the loss of Arctic freshwater biodiversity.
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Affiliation(s)
- Clint C Muhlfeld
- U.S. Geological Survey, Northern Rocky Mountain Science Center, West Glacier, Montana, USA
| | - Timothy J Cline
- Department of Ecology, Montana State University, Bozeman, Montana, USA
| | - Anders G Finstad
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
- Gjærevoll Center for Biodiversity Foresight Analyses, Norwegian University of Science and Technology, Trondheim, Norway
| | - Dag O Hessen
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Sam Perrin
- Gjærevoll Center for Biodiversity Foresight Analyses, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jens Thaulow
- Formerly Employed at Norwegian Institute for Water Research, Oslo, Norway
| | - Diane Whited
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
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6
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Räike A, Taskinen A, Härkönen LH, Kortelainen P, Lepistö A. Browning from headwaters to coastal areas in the boreal region: Trends and drivers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:171959. [PMID: 38537816 DOI: 10.1016/j.scitotenv.2024.171959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 03/05/2024] [Accepted: 03/23/2024] [Indexed: 04/08/2024]
Abstract
Browning of freshwaters, mainly caused by increased terrestrial organic carbon loading, has been widely studied during the last decades. However, there are still uncertainties regarding both the extent of browning in different aquatic ecosystems and the actual importance of different driving forces and mechanisms. To refine understanding of the extent and causes of browning and its temporal variation, we gathered a comprehensive dataset including 746 Finnish water quality monitoring stations representing various waterbody types: streams, rivers, lakes, and coastal waters. Monotonic trend analyses revealed that TOC concentrations increased in all waterbody types during the study period from 1990 to 2020, whereas non-linear trends indicated that upward trends in TOC concentrations have substantially decreased since the mid-2000s. However, despite the upward trends levelling off, non-linear analyses also indicated decreases in TOC concentrations at only a few stations. As a result, the TOC contents of the majority of Finnish waterbody types in 2020 were at a higher level than in 1990. To examine the driving forces of increasing TOC concentrations, we selected 100 riverine catchments and linked the detected trends to 24 different drivers, including both hydrometeorological and catchment characteristics. The increased TOC concentrations in surface waters could be connected to diverse human impacts: hydrometeorological variables impacted by climate change, decreased acidic deposition, and land use in terms of peatland drainage. The importance of increased temperatures was emphasized, and its role as a driver of increased leaching of organic carbon in the forthcoming years is expected to grow with climate change.
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Affiliation(s)
- Antti Räike
- Finnish Environment Institute, Latokartanonkaari 11, FI-00790 Helsinki, Finland.
| | - Antti Taskinen
- Finnish Environment Institute, Latokartanonkaari 11, FI-00790 Helsinki, Finland
| | - Laura H Härkönen
- Finnish Environment Institute, Latokartanonkaari 11, FI-00790 Helsinki, Finland
| | - Pirkko Kortelainen
- Finnish Environment Institute, Latokartanonkaari 11, FI-00790 Helsinki, Finland
| | - Ahti Lepistö
- Finnish Environment Institute, Latokartanonkaari 11, FI-00790 Helsinki, Finland
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7
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Pearson AR, Fox BRS, Hellstrom JC, Vandergoes MJ, Breitenbach SFM, Drysdale RN, Höpker SN, Wood CT, Schiller M, Hartland A. Warming drives dissolved organic carbon export from pristine alpine soils. Nat Commun 2024; 15:3522. [PMID: 38664386 PMCID: PMC11045798 DOI: 10.1038/s41467-024-47706-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Despite decades of research, the influence of climate on the export of dissolved organic carbon (DOC) from soil remains poorly constrained, adding uncertainty to global carbon models. The limited temporal range of contemporary monitoring data, ongoing climate reorganisation and confounding anthropogenic activities muddy the waters further. Here, we reconstruct DOC leaching over the last ~14,000 years using alpine environmental archives (two speleothems and one lake sediment core) across 4° of latitude from Te Waipounamu/South Island of Aotearoa New Zealand. We selected broadly comparable palaeoenvironmental archives in mountainous catchments, free of anthropogenically-induced landscape changes prior to ~1200 C.E. We show that warmer temperatures resulted in increased allochthonous DOC export through the Holocene, most notably during the Holocene Climatic Optimum (HCO), which was some 1.5-2.5 °C warmer than the late pre-industrial period-then decreased during the cooler mid-Holocene. We propose that temperature exerted the key control on the observed doubling to tripling of soil DOC export during the HCO, presumably via temperature-mediated changes in vegetative soil C inputs and microbial degradation rates. Future warming may accelerate DOC export from mountainous catchments, with implications for the global carbon cycle and water quality.
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Affiliation(s)
- Andrew R Pearson
- Environmental Research Institute, School of Science, Faculty of Science and Engineering, University of Waikato, Kirikiriroa Hamilton, Waikato, Aotearoa, New Zealand.
- Institute of Environmental Science and Research (ESR), Ōtautahi Christchurch, Aotearoa, New Zealand.
| | - Bethany R S Fox
- Department of Biological and Geographical Sciences, University of Huddersfield, Huddersfield, UK
| | - John C Hellstrom
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, VIC, Australia
| | | | | | - Russell N Drysdale
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Sebastian N Höpker
- Environmental Research Institute, School of Science, Faculty of Science and Engineering, University of Waikato, Kirikiriroa Hamilton, Waikato, Aotearoa, New Zealand
| | - Christopher T Wood
- Environmental Research Institute, School of Science, Faculty of Science and Engineering, University of Waikato, Kirikiriroa Hamilton, Waikato, Aotearoa, New Zealand
- GNS Science, Te Awa Kairangi ki Tai Lower Hutt, Aotearoa, New Zealand
| | - Martin Schiller
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Adam Hartland
- Environmental Research Institute, School of Science, Faculty of Science and Engineering, University of Waikato, Kirikiriroa Hamilton, Waikato, Aotearoa, New Zealand.
- Lincoln Agritech Ltd, Ruakura, Kirikiriroa Hamilton, Waikato, Aotearoa, New Zealand.
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8
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Wang Z, Shang Y, Li Z, Song K. Analysis of taiga and tundra lake browning trends from 2002 to 2021 using MODIS data. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 356:120576. [PMID: 38513585 DOI: 10.1016/j.jenvman.2024.120576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/22/2023] [Accepted: 03/09/2024] [Indexed: 03/23/2024]
Abstract
Lakes in taiga and tundra regions may be silently undergoing changes due to global warming. One of those changes is browning in lake color. The browning interacts with the carbon cycle, ecosystem dynamics, and water quality in freshwater systems. However, spatiotemporal variabilities of browning in these regions have not been well documented. Using MODIS remote sensing reflectance at near ultraviolet wavelengths from 2002 to 2021 on the Google Earth Engine platform, we quantified long-term browning trends across 7616 lakes (larger than 10 km2) in taiga and tundra biomes. These lakes showed an overall decreased trend in browning (Theil-Sen Slope = 0.00015), with ∼36% of these lakes showing browning trends, and ∼1% of these lakes showing statistically significant (p-value <0.05) browning trends. The browning trends more likely occurred in small lakes in high latitude, low ground ice content regions, where air temperature increased and precipitation decreased. While temperature is projected to increase in response to climate change, our results provide one means to understand how biogeochemical cycles and ecological dynamics respond to climate change.
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Affiliation(s)
- Zijin Wang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yingxin Shang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; State Key Laboratory of Black Soils Conservation and Utilization, China
| | - Zuchuan Li
- Division of Natural and Applied Sciences, Duke Kunshan University, Suzhou, 215316, China
| | - Kaishan Song
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; State Key Laboratory of Black Soils Conservation and Utilization, China; School of Environment and Planning, Liaocheng University, Liaocheng, 252000, China.
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9
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Borgström A, Hansson LA, Klante C, Sjöstedt J. Wetlands as a potential multifunctioning tool to mitigate eutrophication and brownification. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2945. [PMID: 38286682 DOI: 10.1002/eap.2945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/25/2023] [Accepted: 11/16/2023] [Indexed: 01/31/2024]
Abstract
Eutrophication and brownification are ongoing environmental problems affecting aquatic ecosystems. Due to anthropogenic changes, increasing amounts of organic and inorganic compounds are entering aquatic systems from surrounding catchment areas, increasing both nutrients, total organic carbon (TOC), and water color with societal, as well as ecological consequences. Several studies have focused on the ability of wetlands to reduce nutrients, whereas data on their potential to reduce TOC and water color are scarce. Here we evaluate wetlands as a potential multifunctional tool for mitigating both eutrophication and brownification. Therefore, we performed a study for 18 months in nine wetlands allowing us to estimate the reduction in concentrations of total nitrogen (TN), total phosphorus (TP), TOC and water color. We show that wetland reduction efficiency with respect to these variables was generally higher during summer, but many of the wetlands were also efficient during winter. We also show that some, but not all, wetlands have the potential to reduce TOC, water color and nutrients simultaneously. However, the generalist wetlands that reduced all four parameters were less efficient in reducing each of them than the specialist wetlands that only reduced one or two parameters. In a broader context, generalist wetlands have the potential to function as multifunctional tools to mitigate both eutrophication and brownification of aquatic systems. However, further research is needed to assess the design of the generalist wetlands and to investigate the potential of using several specialist wetlands in the same catchment.
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Affiliation(s)
- Anna Borgström
- Department of Biology/Aquatic Ecology, Lund University, Lund, Sweden
| | - Lars-Anders Hansson
- Department of Biology/Aquatic Ecology, Lund University, Lund, Sweden
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Clemens Klante
- Department of Water Resources Engineering, Faculty of Engineering, Lund University, Lund, Sweden
- Sweden Water Research, Ideon Science Park, Lund, Sweden
| | - Johanna Sjöstedt
- Department of Biology/Aquatic Ecology, Lund University, Lund, Sweden
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10
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Bergström AK, Creed IF, Paltsev A, de Wit HA, Lau DCP, Drakare S, Vrede T, Isles PDF, Jonsson A, Geibrink E, Kortelainen P, Vuorenmaa J, Vuorio K, Kahilainen KK, Hessen DO. Declining calcium concentration drives shifts toward smaller and less nutritious zooplankton in northern lakes. GLOBAL CHANGE BIOLOGY 2024; 30:e17220. [PMID: 38433333 DOI: 10.1111/gcb.17220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 01/29/2024] [Accepted: 02/01/2024] [Indexed: 03/05/2024]
Abstract
Zooplankton community composition of northern lakes is changing due to the interactive effects of climate change and recovery from acidification, yet limited data are available to assess these changes combined. Here, we built a database using archives of temperature, water chemistry and zooplankton data from 60 Scandinavian lakes that represent broad spatial and temporal gradients in key parameters: temperature, calcium (Ca), total phosphorus (TP), total organic carbon (TOC), and pH. Using machine learning techniques, we found that Ca was the most important determinant of the relative abundance of all zooplankton groups studied, while pH was second, and TOC third in importance. Further, we found that Ca is declining in almost all lakes, and we detected a critical Ca threshold in lake water of 1.3 mg L-1 , below which the relative abundance of zooplankton shifts toward dominance of Holopedium gibberum and small cladocerans at the expense of Daphnia and copepods. Our findings suggest that low Ca concentrations may shape zooplankton communities, and that current trajectories of Ca decline could promote widespread changes in pelagic food webs as zooplankton are important trophic links from phytoplankton to fish and different zooplankton species play different roles in this context.
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Affiliation(s)
| | - Irena F Creed
- Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Aleksey Paltsev
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Heleen A de Wit
- Centre of Biogeochemistry in the Anthropocene and Department of Bioscience, University of Oslo, Oslo, Norway
- Norwegian Institute for Water Research, Oslo, Norway
| | - Danny C P Lau
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Stina Drakare
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tobias Vrede
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Peter D F Isles
- Watershed Management Division, Vermont Department of Environmental Conservation, Montpelier, Vermont, USA
| | - Anders Jonsson
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Erik Geibrink
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | | | | | | | | | - Dag Olav Hessen
- Centre of Biogeochemistry in the Anthropocene and Department of Bioscience, University of Oslo, Oslo, Norway
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11
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Tong CHM, Noumonvi KD, Ratcliffe J, Laudon H, Järveoja J, Drott A, Nilsson MB, Peichl M. A drained nutrient-poor peatland forest in boreal Sweden constitutes a net carbon sink after integrating terrestrial and aquatic fluxes. GLOBAL CHANGE BIOLOGY 2024; 30:e17246. [PMID: 38501699 DOI: 10.1111/gcb.17246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 02/15/2024] [Accepted: 02/27/2024] [Indexed: 03/20/2024]
Abstract
Northern peatlands provide a globally important carbon (C) store. Since the beginning of the 20th century, however, large areas of natural peatlands have been drained for biomass production across Fennoscandia. Today, drained peatland forests constitute a common feature of the managed boreal landscape, yet their ecosystem C balance and associated climate impact are not well understood, particularly within the nutrient-poor boreal region. In this study, we estimated the net ecosystem carbon balance (NECB) from a nutrient-poor drained peatland forest and an adjacent natural mire in northern Sweden by integrating terrestrial carbon dioxide (CO2 ) and methane (CH4 ) fluxes with aquatic losses of dissolved organic C (DOC) and inorganic C based on eddy covariance and stream discharge measurements, respectively, over two hydrological years. Since the forest included a dense spruce-birch area and a sparse pine area, we were able to further evaluate the effect of contrasting forest structure on the NECB and component fluxes. We found that the drained peatland forest was a net C sink with a 2-year mean NECB of -115 ± 5 g C m-2 year-1 while the adjacent mire was close to C neutral with 14.6 ± 1.7 g C m-2 year-1 . The NECB of the drained peatland forest was dominated by the net CO2 exchange (net ecosystem exchange [NEE]), whereas NEE and DOC export fluxes contributed equally to the mire NECB. We further found that the C sink strength in the sparse pine forest area (-153 ± 8 g C m-2 year-1 ) was about 1.5 times as high as in the dense spruce-birch forest area (-95 ± 8 g C m-2 year-1 ) due to enhanced C uptake by ground vegetation and lower DOC export. Our study suggests that historically drained peatland forests in nutrient-poor boreal regions may provide a significant net ecosystem C sink and associated climate benefits.
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Affiliation(s)
- Cheuk Hei Marcus Tong
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Koffi Dodji Noumonvi
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Joshua Ratcliffe
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
- Unit for Field-Based Forest Research, Swedish University of Agricultural Sciences, Vindeln, Sweden
| | - Hjalmar Laudon
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Järvi Järveoja
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
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12
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Turunen J, Aroviita J. Influence of water color and catchment lake cover on stream macroinvertebrate communities: Ecological insights into browning effects. WATER RESEARCH 2024; 250:121048. [PMID: 38157603 DOI: 10.1016/j.watres.2023.121048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/10/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
Browning of streams due to increased export of dissolved organic carbon (DOC) and iron has been observed in vast areas of the northern hemisphere with likely adverse ecological effects. Lake basins in stream catchments can moderate DOC export and influence stream communities, which complicates understanding of the effects of DOC. In this study, we explored the independent and interactive effects of water color (proxy for DOC and iron) and catchment lake cover on benthic macroinvertebrate communities in 94 medium-sized boreal forest streams. We first investigated the role of lake basins and other catchment characteristics in controlling water color. We then studied the effects of water color and catchment lake cover on macroinvertebrate community composition, biodiversity, and functional feeding traits. Water color correlated negatively with catchment lake cover, whereas the correlation with peatland cover and drainage intensity was positive. PERMANOVA and GLS analyses indicated that both color and catchment lake cover had a distinct independent effect on invertebrate community composition and community attributes, without significant interactions. Color had an independent negative effect on EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa richness irrespective of lake cover. Increasing water color had negative effect on relative abundance of grazer, but no significant effect on shredder trait, while lake cover had a negative effect on both of the traits. Lake cover exhibited a negative influence on collector-gatherers, and a positive effect on filter feeders, while the predators were positively affected by both factors. The results highlight that water color influences the community structure of boreal stream ecosystems, and the effects are similar regardless of catchment lake cover. Mitigation measures should be emphasized, aimed at reducing DOC and iron runoff, in land use planning and river basin management.
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Affiliation(s)
- Jarno Turunen
- Marine and Freshwater Solutions, Finnish Environment Institute, PO Box 413, Oulu 90014, Finland.
| | - Jukka Aroviita
- Marine and Freshwater Solutions, Finnish Environment Institute, PO Box 413, Oulu 90014, Finland
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13
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Schultze S, Andersen T, Knudtzon N, Ruus A, Rundberget JT, Brooks SJ, Poste A, Hessen DO, Borgå K. Do DOM quality and origin affect the uptake and accumulation of lipid-soluble contaminants in coastal filter feeders? An experimental simulation of teflubenzuron exposure to blue mussels. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 263:106696. [PMID: 37757569 DOI: 10.1016/j.aquatox.2023.106696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 08/28/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023]
Abstract
The increased export of terrestrial dissolved organic matter (terrDOM) to coastal marine ecosystems may affect local filter feeders and the local food web via the altered uptake of organic material and associated contaminants. To compare terrDOM to marine DOM (marDOM) as contaminant vectors to coastal biota, we exposed blue mussels (Mytilus sp.) to the different DOM types in combination with teflubenzuron, a widely applied lipophilic aquaculture medicine targeting salmon lice (Lepeophtheirus salmonis). A 16-day exposure of the blue mussels to DOM and teflubenzuron was followed by a depuration phase of 20 days without teflubenzuron. We calculated teflubenzuron adsorption rates and bioaccumulation factors (BAF) using a Bayesian model, expecting teflubenzuron uptake to be greater with terrDOM than marDOM due to the higher prevalence of large amphipathic humic acids in terrDOM. Humic acids have strong absorption properties and are able to envelope lipophilic molecules. Thus, humic acids can function as an efficient contaminant vector when taken up by filter feeders. Although there were varying degrees of overlap, the mussels tended to accumulate higher amounts of teflubenzuron in the DOM treatments than in the seawater control (bioaccumulation factor [BAF] in seawater: median 106 L/kg; 2.5 %-97.5 % percentile: 69-160 L/kg). Contrary to expectations, mussels exposed to marDOM showed a trend toward more bioaccumulation of teflubenzuron than those exposed to terrDOM (BAF marine 144 L/kg; 102-221 L/kg versus BAF terrestrial: 121 L/kg; 82-186 L/kg). The highest teflubenzuron accumulation was observed with the 50:50 mixture of marDOM and terrDOM (BAF mix: 165 L/kg; 117-244 L/kg). The slight difference in DOM-type accumulation rates observed in this experiment-especially the accumulation rate of terrDOM compared to that of the seawater-only treatment type-was not considered environmentally relevant. Further studies are necessary to see if the observed trends transfer to complex environmental systems.
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Affiliation(s)
- Sabrina Schultze
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway.
| | - Tom Andersen
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | - Nina Knudtzon
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | - Anders Ruus
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway; Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway
| | - Jan T Rundberget
- Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway
| | - Steven J Brooks
- Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway
| | - Amanda Poste
- Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway; UiT-The Arctic University of Norway, Tromsø 9037, Norway; Norwegian Institute for Nature Research, Fram Centre for High North Research, Hjalmar Johansens gate 14, 9007 Tromsø, Norway
| | - Dag O Hessen
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
| | - Katrine Borgå
- Department of Biosciences, Aquatic Biology and Toxicology and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo 0316, Norway
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14
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Imtiazy MN, Hunter K, Sereda J, Dirk L, Hudson JJ. Effects of regional climate, hydrology and river impoundment on long-term patterns and characteristics of dissolved organic matter in semi-arid northern plains rivers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:161961. [PMID: 36737025 DOI: 10.1016/j.scitotenv.2023.161961] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/28/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Diverse environmental and anthropogenic factors, such as the ongoing reservoir constructions may influence riverine dissolved organic matter (DOM) properties. This has important implications for river water quality, particularly when reservoirs are a source of drinking water. Simultaneous studies of multidecadal trends in dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) are scarce. We studied the patterns in DOC and DON concentration in two major rivers of the South Saskatchewan River (SSR) basin over a 42-year period (1978-2019). We also examined the impact of a large reservoir on riverine DOC properties. Contrary to many studies, we did not find a long-term increase in DOC and DON concentration, and DOC and DON patterns were not always synchronous. In an agriculture dominated watershed like the SSR basin, agricultural land use (e.g., nitrogen-fertilizer application) could influence DOC and DON concentration differently, potentially resulting in asynchronous patterns over time. River discharge was an important driver of DOM patterns. Regional precipitation in the lower SSR basin may also influence DOM patterns in locations where runoff contribution is greater. These regional factors explained greater variability in DOM compared to global scale indices (e.g., Pacific decadal oscillation) due to their direct control on DOM. A travel time corrected approach to account for the lengthy reservoir turnover time showed that a large reservoir caused a reduction in allochthonous DOC characteristics through photodegradation and perhaps, an increase in autochthonous characteristics. Our results illustrate: 1) the increase in DOM concentrations seen in the northern hemisphere is not present in semi-arid prairie rivers, 2) Controls on different DOM components could be different, and 3) large reservoirs may modify riverine DOC composition due to longer water residence time.
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Affiliation(s)
- Md Noim Imtiazy
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Kristine Hunter
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Jeff Sereda
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
| | - Leah Dirk
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Jeff J Hudson
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
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15
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Puts IC, Ask J, Deininger A, Jonsson A, Karlsson J, Bergström A. Browning affects pelagic productivity in northern lakes by surface water warming and carbon fertilization. GLOBAL CHANGE BIOLOGY 2023; 29:375-390. [PMID: 36197126 PMCID: PMC10092479 DOI: 10.1111/gcb.16469] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Global change impacts important environmental drivers for pelagic gross primary production (GPP) in northern lakes, such as temperature, light, nutrient, and inorganic carbon availability. Separate and/or synergistic impacts of these environmental drivers on pelagic GPP remain largely unresolved. Here, we assess key drivers of pelagic GPP by combining detailed depth profiles of summer pelagic GPP with environmental and climatic data across 45 small and shallow lakes across northern Sweden (20 boreal, 6 subarctic, and 19 arctic lakes). We found that across lakes summer pelagic GPP was strongest associated with lake water temperatures, lake carbon dioxide (CO2 ) concentrations impacted by lake water pH, and further moderated by dissolved organic carbon (DOC) concentrations influencing light and nutrient conditions. We further used this dataset to assess the extent of additional DOC-induced warming of epilimnia (here named internal warming), which was especially pronounced in shallow lakes (decreasing 0.96°C for every decreasing m in average lake depth) and increased with higher concentrations of DOC. Additionally, the total pools and relative proportion of dissolved inorganic carbon and DOC, further influenced pelagic GPP with drivers differing slightly among the boreal, subarctic and Arctic biomes. Our study provides novel insights in that global change affects pelagic GPP in northern lakes not only by modifying the organic carbon cycle and light and nutrient conditions, but also through modifications of inorganic carbon supply and temperature. Considering the large-scale impacts and similarities of global warming, browning and recovery from acidification of lakes at higher latitudes throughout the northern hemisphere, these changes are likely to operate on a global scale.
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Affiliation(s)
- Isolde C. Puts
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Jenny Ask
- Umeå Marine Sciences CentreUmeå UniversityUmeåSweden
| | | | - Anders Jonsson
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Jan Karlsson
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Ann‐Kristin Bergström
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
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16
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McCarter CPR, Sebestyen SD, Coleman Wasik JK, Engstrom DR, Kolka RK, Jeremiason JD, Swain EB, Monson BA, Branfireun BA, Balogh SJ, Nater EA, Eggert SL, Ning P, Mitchell CPJ. Long-Term Experimental Manipulation of Atmospheric Sulfate Deposition to a Peatland: Response of Methylmercury and Related Solute Export in Streamwater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17615-17625. [PMID: 36445185 DOI: 10.1021/acs.est.2c02621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Changes in sulfate (SO42-) deposition have been linked to changes in mercury (Hg) methylation in peatlands and water quality in freshwater catchments. There is little empirical evidence, however, of how quickly methyl-Hg (MeHg, a bioaccumulative neurotoxin) export from catchments might change with declining SO42- deposition. Here, we present responses in total Hg (THg), MeHg, total organic carbon, pH, and SO42- export from a peatland-dominated catchment as a function of changing SO42- deposition in a long-term (1998-2011), whole-ecosystem, control-impact experiment. Annual SO42- deposition to half of a 2-ha peatland was experimentally increased 6-fold over natural levels and then returned to ambient levels in two phases. Sulfate additions led to a 5-fold increase in monthly flow-weighted MeHg concentrations and yields relative to a reference catchment. Once SO42- additions ceased, MeHg concentrations in the outflow streamwater returned to pre-SO42- addition levels within 2 years. The decline in streamwater MeHg was proportional to the change in the peatland area no longer receiving experimental SO42- inputs. Importantly, net demethylation and increased sorption to peat hastened the return of MeHg to baseline levels beyond purely hydrological flushing. Overall, we present clear empirical evidence of rapid and proportionate declines in MeHg export from a peatland-dominated catchment when SO42- deposition declines.
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Affiliation(s)
- Colin P R McCarter
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Scarborough, OntarioM1C 1A4, Canada
| | - Stephen D Sebestyen
- USDA Forest Service Northern Research Station, Grand Rapids, Minnesota55744, United States
| | - Jill K Coleman Wasik
- Department of Plant and Earth Science, University of Wisconsin - River Falls, 410 S. 3rd Street, River Falls, Wisconsin54022, United States
| | - Daniel R Engstrom
- St. Croix Watershed Research Station, Science Museum of Minnesota, 16910 152nd Street N., Marine on St. Croix, Minnesota55047, United States
| | - Randall K Kolka
- USDA Forest Service Northern Research Station, Grand Rapids, Minnesota55744, United States
| | - Jeff D Jeremiason
- Department of Chemistry, Gustavus Adolphus College, 800 W College AvenueSt. Peter, Minnesota56082, United States
| | - Edward B Swain
- Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, Minnesota55108, United States
| | - Bruce A Monson
- Minnesota Pollution Control Agency, 520 Lafayette Road North, Saint Paul, Minnesota55155, United States
| | - Brian A Branfireun
- Department of Biology, The University of Western Ontario, London, OntarioN5B 2A7, Canada
| | - Steven J Balogh
- Metropolitan Council Environmental Services, 2400 Childs Road, Saint Paul, Minnesota55106, United States
| | - Edward A Nater
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, Minnesota55108, United States
| | - Susan L Eggert
- USDA Forest Service Northern Research Station, Grand Rapids, Minnesota55744, United States
| | - Paris Ning
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Scarborough, OntarioM1C 1A4, Canada
| | - Carl P J Mitchell
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Scarborough, OntarioM1C 1A4, Canada
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17
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Puts IC, Ask J, Siewert MB, Sponseller RA, Hessen DO, Bergström A. Landscape determinants of pelagic and benthic primary production in northern lakes. GLOBAL CHANGE BIOLOGY 2022; 28:7063-7077. [PMID: 36054573 PMCID: PMC9826228 DOI: 10.1111/gcb.16409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/01/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Global change affects gross primary production (GPP) in benthic and pelagic habitats of northern lakes by influencing catchment characteristics and lake water biogeochemistry. However, how changes in key environmental drivers manifest and impact total (i.e., benthic + pelagic) GPP and the partitioning of total GPP between habitats represented by the benthic share (autotrophic structuring) is unclear. Using a dataset from 26 shallow lakes located across Arctic, subarctic, and boreal northern Sweden, we investigate how catchment properties (air temperature, land cover, hydrology) affect lake physico-chemistry and patterns of total GPP and autotrophic structuring. We find that total GPP was mostly light limited, due to high dissolved organic carbon (DOC) concentrations originating from catchment soils with coniferous vegetation and wetlands, which is further promoted by high catchment runoff. In contrast, autotrophic structuring related mostly to the relative size of the benthic habitat, and was potentially modified by CO2 fertilization in the subarctic, resulting in significantly higher total GPP relative to the other biomes. Across Arctic and subarctic sites, DIC and CO2 were unrelated to DOC, indicating that external inputs of inorganic carbon can influence lake productivity patterns independent of terrestrial DOC supply. By comparison, DOC and CO2 were correlated across boreal lakes, suggesting that DOC mineralization acts as an important CO2 source for these sites. Our results underline that GPP as a resource is regulated by landscape properties, and is sensitive to large-scale global changes (warming, hydrological intensification, recovery of acidification) that promote changes in catchment characteristics and aquatic physico-chemistry. Our findings aid in predicting global change impacts on autotrophic structuring, and thus community structure and resource use of aquatic consumers in general. Given the similarities of global changes across the Northern hemisphere, our findings are likely relevant for northern lakes globally.
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Affiliation(s)
- Isolde Callisto Puts
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Jenny Ask
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Matthias B. Siewert
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Ryan A. Sponseller
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | | | - Ann‐Kristin Bergström
- Climate Impacts Research Centre, Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
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18
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Drivers and variability of CO 2:O 2 saturation along a gradient from boreal to Arctic lakes. Sci Rep 2022; 12:18989. [PMID: 36348044 PMCID: PMC9643447 DOI: 10.1038/s41598-022-23705-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Lakes are significant players for the global climate since they sequester terrestrially derived dissolved organic carbon (DOC), and emit greenhouse gases like CO2 to the atmosphere. However, the differences in environmental drivers of CO2 concentrations are not well constrained along latitudinal and thus climate gradients. Our aim here is to provide a better understanding of net heterotrophy and gas balance at the catchment scale in a set of boreal, sub-Arctic and high-Arctic lakes. We assessed water chemistry and concentrations of dissolved O2 and CO2, as well as the CO2:O2 ratio in three groups of lakes separated by steps of approximately 10 degrees latitude in South-Eastern Norway (near 60° N), sub-Arctic lakes in the northernmost part of the Norwegian mainland (near 70° N) and high-Arctic lakes on Svalbard (near 80° N). Across all regions, CO2 saturation levels varied more (6-1374%) than O2 saturation levels (85-148%) and hence CO2 saturation governed the CO2:O2 ratio. The boreal lakes were generally undersaturated with O2, while the sub-Arctic and high-Arctic lakes ranged from O2 saturated to oversaturated. Regardless of location, the majority of the lakes were CO2 supersaturated. In the boreal lakes the CO2:O2 ratio was mainly related to DOC concentration, in contrast to the sub-Arctic and high-Arctic localities, where conductivity was the major statistical determinant. While the southern part is dominated by granitic and metamorphic bedrock, the sub-Arctic sites are scattered across a range of granitic to sedimentary bed rocks, and the majority of the high-Arctic lakes are situated on limestone, resulting in contrasting lake alkalinities between the regions. DOC dependency of the CO2:O2 ratio in the boreal region together with low alkalinity suggests that in-lake heterotrophic respiration was a major source of lake CO2. Contrastingly, the conductivity dependency indicates that CO2 saturation in the sub-Arctic and high-Arctic lakes was to a large part explained by DIC input from catchment respiration and carbonate weathering.
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19
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Nieminen M, Hasselquist EM, Mosquera V, Ukonmaanaho L, Sallantaus T, Sarkkola S. Post-drainage stand growth and peat mineralization impair water quality from forested peatlands. JOURNAL OF ENVIRONMENTAL QUALITY 2022; 51:1211-1221. [PMID: 36096489 DOI: 10.1002/jeq2.20412] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
Many recent studies have indicated upward trends in carbon and nutrient concentrations from drained peatland forests over time since their initial drainage, but the mechanisms behind these trends are still poorly understood. We gathered data on nitrogen and phosphorus concentrations discharged from 37 drained boreal peatland forests where we also had data on peat and tree stand characteristics. We found that tree stand volume and peat bulk density were positively correlated with the nitrogen and phosphorus concentrations discharged from particularly the deep-peated sites. We interpret these results to indicate that a plausible reason for the reported upward trends in nutrient concentrations is the maturing and growing of the tree stands over time since initial drainage and the consequent increasing evapotranspiration capacity, which results in lowered soil water levels and enhanced aerobic peat mineralization. We discuss how our results should be considered in the management of drained peatland forests.
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Affiliation(s)
- Mika Nieminen
- Natural Resources Institute Finland, Latokartanonkaari 9, Helsinki, FI-00790, Finland
| | - Eliza Maher Hasselquist
- Dep. of Forest Ecology and Management, Swedish Univ. of Agricultural Sciences, Umeå, 901 83, Sweden
| | - Virginia Mosquera
- Dep. of Forest Ecology and Management, Swedish Univ. of Agricultural Sciences, Umeå, 901 83, Sweden
| | - Liisa Ukonmaanaho
- Natural Resources Institute Finland, Latokartanonkaari 9, Helsinki, FI-00790, Finland
| | - Tapani Sallantaus
- Finnish Environment Institute, Latokartanonkaari 11, Helsinki, FI-00790, Finland
| | - Sakari Sarkkola
- Natural Resources Institute Finland, Latokartanonkaari 9, Helsinki, FI-00790, Finland
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20
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Pilla RM, Griffiths NA, Gu L, Kao SC, McManamay R, Ricciuto DM, Shi X. Anthropogenically driven climate and landscape change effects on inland water carbon dynamics: What have we learned and where are we going? GLOBAL CHANGE BIOLOGY 2022; 28:5601-5629. [PMID: 35856254 DOI: 10.1111/gcb.16324] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/05/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Inland waters serve as important hydrological connections between the terrestrial landscape and oceans but are often overlooked in global carbon (C) budgets and Earth System Models. Terrestrially derived C entering inland waters from the watershed can be transported to oceans but over 83% is either buried in sediments or emitted to the atmosphere before reaching oceans. Anthropogenic pressures such as climate and landscape changes are altering the magnitude of these C fluxes in inland waters. Here, we synthesize the most recent estimates of C fluxes and the differential contributions across inland waterbody types (rivers, streams, lakes, reservoirs, and ponds), including recent measurements that incorporate improved sampling methods, small waterbodies, and dried areas. Across all inland waters, we report a global C emission estimate of 4.40 Pg C/year (95% confidence interval: 3.95-4.85 Pg C/year), representing a 13% increase from the most recent estimate. We also review the mechanisms by which the most globally widespread anthropogenically driven climate and landscape changes influence inland water C fluxes. The majority of these drivers are expected to influence terrestrial C inputs to inland waters due to alterations in terrestrial C quality and quantity, hydrological pathways, and biogeochemical processing. We recommend four research priorities for the future study of anthropogenic alterations to inland water C fluxes: (1) before-and-after measurements of C fluxes associated with climate change events and landscape changes, (2) better quantification of C input from land, (3) improved assessment of spatial coverage and contributions of small inland waterbodies to C fluxes, and (4) integration of dried and drawdown areas to global C flux estimates. Improved measurements of inland water C fluxes and quantification of uncertainty in these estimates will be vital to understanding both terrestrial C losses and the "moving target" of inland water C emissions in response to rapid and complex anthropogenic pressures.
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Affiliation(s)
- Rachel M Pilla
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Natalie A Griffiths
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Lianhong Gu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Shih-Chieh Kao
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Ryan McManamay
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Department of Environmental Science, Baylor University, Waco, Texas, USA
| | - Daniel M Ricciuto
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Xiaoying Shi
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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21
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Neweshy W, Planas D, Tellier E, Demers M, Marsac R, Couture RM. Response of sediment phosphorus partitioning to lanthanum-modified clay amendment and porewater chemistry in a small eutrophic lake. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1494-1507. [PMID: 35635543 DOI: 10.1039/d1em00544h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Sustained eutrophication of the aquatic environment by the remobilization of legacy phosphorus (P) stored in soils and sediments is a prevailing issue worldwide. Fluxes of P from the sediments to the water column, referred to as internal P loading, often delays the recovery of water quality following a reduction in external P loads. Here, we report on the vertical distribution and geochemistry of P, lanthanum (La), iron (Fe) and carbon (C) in the culturally eutrophied Lake Bromont. This lake underwent remediation treatment using La modified bentonite (LMB) commercially available as Phoslock™. We investigated the effectiveness of LMB in decreasing soluble reactive phosphorus (SRP) availability in sediments and in reducing dissolved fluxes of P across the sediment-water interface. Sediment cores were retrieved before and after LMB treatment at three sites representing bottom sediment, sediment influenced by lakeside housing and finally littoral sediment influenced by the lake inflow. Sequential extractions were used to assess changes in P speciation. Depth profiles of dissolved porewater concentrations were obtained after LMB treatment at each site. Results indicate that SRP extracted from the sediments decreased at all sites, while total extracted P (PTOT) bound to redox-sensitive metal oxides increased. 31P NMR data on P extract reveals that 20-43% of total solid-phase P is in the form of organic P (Porg) susceptible to be released via microbial degradation. Geochemical modelling of porewater data provides evidence that LaPO4(s) mineral phases, such as rhabdophane and/or monazite, are likely forming. However, results also suggest that La3+ binding by dissolved organic carbon (DOC) hinders La-phosphate precipitation. We rely on thermodynamic modelling to suggest that high Fe2+ would bind to DOC instead of La3+, therefore promoting P sequestrations by LMB under anoxic conditions.
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Affiliation(s)
- Wessam Neweshy
- Department of Chemistry, Université Laval, Québec Canada and GRIL (Interuniversity Research Group in Limnology), Canada.
| | - Dolors Planas
- Département de Sciences Biologiques, Université de Québec à Montréal, Canada and GRIL (Interuniversity Research Group in Limnology), Montréal, Canada
| | - Elisabeth Tellier
- Action Conservation du Bassin Versant du Lac Bromont, Bromont, Québec, Canada
| | - Marie Demers
- Department of Chemistry, Université Laval, Québec Canada and GRIL (Interuniversity Research Group in Limnology), Canada.
| | - Remi Marsac
- Univ Rennes, CNRS, Géosciences Rennes-UMR 6118, F-35000 Rennes, France
| | - Raoul-Marie Couture
- Department of Chemistry, Université Laval, Québec Canada and GRIL (Interuniversity Research Group in Limnology), Canada.
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22
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Kragh T, Sand-Jensen K, Kristensen E, Pedersen O, Madsen-Østerbye M. Removal of chromophoric dissolved organic matter under combined photochemical and microbial degradation as a response to different irradiation intensities. J Environ Sci (China) 2022; 118:76-86. [PMID: 35305775 DOI: 10.1016/j.jes.2021.08.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 06/14/2023]
Abstract
Throughout the freshwater continuum, Dissolved Organic Carbon (DOC) and the colored fraction, Chromophoric Dissolved Organic Material (CDOM), are continuously being added, removed, and transformed, resulting in changes in the chromophoricity and lability of organic matter over time. We examined, experimentally, the effect of increasing irradiation-intensities on the combined photochemical and microbial degradation of CDOM and DOC. This was done by using a simulated mixed water column: aged water from a humic lake was exposed to four irradiation-intensities - representing winter, early and late spring, and summer conditions (0.10, 0.16, 0.36, and 0.58 W/m2) - and compared with dark controls over 37 days. We found a linear relationship between CDOM degradation and irradiation-intensities up to 0.36 W/m2; the degradation rate saturated at higher intensities, both at specific wavelengths and for broader intervals. After 37 days at high irradiation-intensity, CDOM absorption of irradiation at 340 nm had been reduced by 41%; 48% of DOC had been removed and DOC degradation continued to increase. Aromaticity (SUVA254) declined significantly over 37 days at the two lowest but not at the two highest UV- intensities; levels in unexposed control water remained constant. Direct observations of the humic lake showed that CDOM absorption of irradiation (340 nm) declined by 27% from winter to summer. A model based on hydrological CDOM input and CDOM degradation calculated from field measurements of UV-radiation and experimental CDOM degradation with UV-exposure from sunlight accurately predicted the annual course as observed in the lake. With no external CDOM input, 92% of the CDOM could be degraded in a year. The results support the notion that combined photochemical and microbial CDOM degradation can be remarkably higher in lakes than previously thought and that humic lakes retain their color due to light absorption by ongoing CDOM input.
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Affiliation(s)
- Theis Kragh
- Department of Biology, University of Southern Denmark, Syddanmark 5230, Denmark.
| | - Kaj Sand-Jensen
- Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Emil Kristensen
- Department of Biology, University of Southern Denmark, Syddanmark 5230, Denmark; Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Ole Pedersen
- Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Mikkel Madsen-Østerbye
- Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark
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23
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Chételat J, McKinney MA, Amyot M, Dastoor A, Douglas TA, Heimbürger-Boavida LE, Kirk J, Kahilainen KK, Outridge PM, Pelletier N, Skov H, St Pierre K, Vuorenmaa J, Wang F. Climate change and mercury in the Arctic: Abiotic interactions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 824:153715. [PMID: 35149079 DOI: 10.1016/j.scitotenv.2022.153715] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Dramatic environmental shifts are occuring throughout the Arctic from climate change, with consequences for the cycling of mercury (Hg). This review summarizes the latest science on how climate change is influencing Hg transport and biogeochemical cycling in Arctic terrestrial, freshwater and marine ecosystems. As environmental changes in the Arctic continue to accelerate, a clearer picture is emerging of the profound shifts in the climate and cryosphere, and their connections to Hg cycling. Modeling results suggest climate influences seasonal and interannual variability of atmospheric Hg deposition. The clearest evidence of current climate change effects is for Hg transport from terrestrial catchments, where widespread permafrost thaw, glacier melt and coastal erosion are increasing the export of Hg to downstream environments. Recent estimates suggest Arctic permafrost is a large global reservoir of Hg, which is vulnerable to degradation with climate warming, although the fate of permafrost soil Hg is unclear. The increasing development of thermokarst features, the formation and expansion of thaw lakes, and increased soil erosion in terrestrial landscapes are increasing river transport of particulate-bound Hg and altering conditions for aquatic Hg transformations. Greater organic matter transport may also be influencing the downstream transport and fate of Hg. More severe and frequent wildfires within the Arctic and across boreal regions may be contributing to the atmospheric pool of Hg. Climate change influences on Hg biogeochemical cycling remain poorly understood. Seasonal evasion and retention of inorganic Hg may be altered by reduced sea-ice cover and higher chloride content in snow. Experimental evidence indicates warmer temperatures enhance methylmercury production in ocean and lake sediments as well as in tundra soils. Improved geographic coverage of measurements and modeling approaches are needed to better evaluate net effects of climate change and long-term implications for Hg contamination in the Arctic.
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Affiliation(s)
- John Chételat
- Environment and Climate Change Canada, Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Ottawa, ON K1A 0H3, Canada.
| | - Melissa A McKinney
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Marc Amyot
- Groupe de recherche interuniversitaire en limnologie (GRIL), Département de sciences biologiques, Complexe des Sciences, Montréal, QC H2V 0B3, Canada
| | - Ashu Dastoor
- Environment and Climate Change Canada, Air Quality Research Division, Dorval, QC H9P 1J3, Canada
| | - Thomas A Douglas
- U.S. Army Cold Regions Research and Engineering Laboratory, Fort Wainwright, AK 99709, USA
| | - Lars-Eric Heimbürger-Boavida
- Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Marseille, France
| | - Jane Kirk
- Environment and Climate Change Canada, Aquatic Contaminants Research Division, Burlington, ON L7S 1A1, Canada
| | - Kimmo K Kahilainen
- Lammi Biological Station, University of Helsinki, Pääjärventie 320, FI-16900 Lammi, Finland
| | - Peter M Outridge
- Geological Survey of Canada, Natural Resources Canada, Ottawa, ON K1A 0E8, Canada
| | - Nicolas Pelletier
- Geography and Environmental Studies, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Henrik Skov
- Department of Environmental Science, iClimate, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Kyra St Pierre
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Jussi Vuorenmaa
- Finnish Environment Institute (SYKE), Latokartanonkaari 11, FI-00790 Helsinki, Finland
| | - Feiyue Wang
- Centre for Earth Observation Sciences (CEOS), Dept. of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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24
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Abstract
AbstractNutrient inputs to northern freshwaters are changing, potentially altering aquatic ecosystem functioning through effects on primary producers. Yet, while primary producer growth is sensitive to nutrient supply, it is also constrained by a suite of other factors, including light and temperature, which may play varying roles across stream and lake habitats. Here, we use bioassay results from 89 lakes and streams spanning northern boreal to Arctic Sweden to test for differences in nutrient limitation status of algal biomass along gradients in colored dissolved organic carbon (DOC), water temperature, and nutrient concentrations, and to ask whether there are distinct patterns and drivers between habitats. Single nitrogen (N) limitation or primary N-limitation with secondary phosphorus (P) limitation of algal biomass was the most common condition for streams and lakes. Average response to N-addition was a doubling in biomass; however, the degree of limitation was modulated by the distinct physical and chemical conditions in lakes versus streams and across boreal to Arctic regions. Overall, algal responses to N-addition were strongest at sites with low background concentrations of dissolved inorganic N. Low temperatures constrained biomass responses to added nutrients in lakes but had weaker effects on responses in streams. Further, DOC mediated the response of algal biomass to nutrient addition differently among lakes and streams. Stream responses were dampened at higher DOC, whereas lake responses to nutrient addition increased from low to moderate DOC but were depressed at high DOC. Our results suggest that future changes in nutrient availability, particularly N, will exert strong effects on the trophic state of northern freshwaters. However, we highlight important differences in the physical and chemical factors that shape algal responses to nutrient availability in different parts of aquatic networks, which will ultimately affect the integrated response of northern aquatic systems to ongoing environmental changes.
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25
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Zhu X, Chen L, Pumpanen J, Ojala A, Zobitz J, Zhou X, Laudon H, Palviainen M, Neitola K, Berninger F. The role of terrestrial productivity and hydrology in regulating aquatic dissolved organic carbon concentrations in boreal catchments. GLOBAL CHANGE BIOLOGY 2022; 28:2764-2778. [PMID: 35060250 PMCID: PMC9303698 DOI: 10.1111/gcb.16094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/26/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
The past decades have witnessed an increase in dissolved organic carbon (DOC) concentrations in the catchments of the Northern Hemisphere. Increasing terrestrial productivity and changing hydrology may be reasons for the increases in DOC concentration. The aim of this study is to investigate the impacts of increased terrestrial productivity and changed hydrology following climate change on DOC concentrations. We tested and quantified the effects of gross primary production (GPP), ecosystem respiration (RE) and discharge on DOC concentrations in boreal catchments over 3 years. As catchment characteristics can regulate the extent of rising DOC concentrations caused by the regional or global environmental changes, we selected four catchments with different sizes (small, medium and large) and landscapes (forest, mire and forest-mire mixed). We applied multiple models: Wavelet coherence analysis detected the delay-effects of terrestrial productivity and discharge on aquatic DOC variations of boreal catchments; thereafter, the distributed-lag linear models quantified the contributions of each factor on DOC variations. Our results showed that the combined impacts of terrestrial productivity and discharge explained 62% of aquatic DOC variations on average across all sites, whereas discharge, gross primary production (GPP) and RE accounted for 26%, 22% and 3%, respectively. The impact of GPP and discharge on DOC changes was directly related to catchment size: GPP dominated DOC fluctuations in small catchments (<1 km2 ), whereas discharge controlled DOC variations in big catchments (>1 km2 ). The direction of the relation between GPP and discharge on DOC varied. Increasing RE always made a positive contribution to DOC concentration. This study reveals that climate change-induced terrestrial greening and shifting hydrology change the DOC export from terrestrial to aquatic ecosystems. The work improves our mechanistic understanding of surface water DOC regulation in boreal catchments and confirms the importance of DOC fluxes in regulating ecosystem C budgets.
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Affiliation(s)
- Xudan Zhu
- Department of Environmental and Biological SciencesJoensuu CampusUniversity of Eastern FinlandJoensuuFinland
| | - Liang Chen
- Department of Environmental and Biological SciencesJoensuu CampusUniversity of Eastern FinlandJoensuuFinland
| | - Jukka Pumpanen
- Department of Environmental and Biological SciencesKuopio CampusUniversity of Eastern FinlandKuopioFinland
| | - Anne Ojala
- Natural Resources Institute Finland (LUKE)HelsinkiFinland
| | - John Zobitz
- Department of Mathematics, Statistics, and Computer ScienceAugsburg UniversityMinneapolisMinnesotaUSA
| | - Xuan Zhou
- Department of Environmental and Biological SciencesJoensuu CampusUniversity of Eastern FinlandJoensuuFinland
| | - Hjalmar Laudon
- Department of Forest Ecology and ManagementSwedish University of Agricultural ScienceUmeåSweden
| | - Marjo Palviainen
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
| | - Kimmo Neitola
- Institute for Atmospheric Earth System Research (INAR)University of HelsinkiHelsinkiFinland
| | - Frank Berninger
- Department of Environmental and Biological SciencesJoensuu CampusUniversity of Eastern FinlandJoensuuFinland
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26
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Blanchet CC, Arzel C, Davranche A, Kahilainen KK, Secondi J, Taipale S, Lindberg H, Loehr J, Manninen-Johansen S, Sundell J, Maanan M, Nummi P. Ecology and extent of freshwater browning - What we know and what should be studied next in the context of global change. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 812:152420. [PMID: 34953836 DOI: 10.1016/j.scitotenv.2021.152420] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Water browning or brownification refers to increasing water color, often related to increasing dissolved organic matter (DOM) and carbon (DOC) content in freshwaters. Browning has been recognized as a significant physicochemical phenomenon altering boreal lakes, but our understanding of its ecological consequences in different freshwater habitats and regions is limited. Here, we review the consequences of browning on different freshwater habitats, food webs and aquatic-terrestrial habitat coupling. We examine global trends of browning and DOM/DOC, and the use of remote sensing as a tool to investigate browning from local to global scales. Studies have focused on lakes and rivers while seldom addressing effects at the catchment scale. Other freshwater habitats such as small and temporary waterbodies have been overlooked, making the study of the entire network of the catchment incomplete. While past research investigated the response of primary producers, aquatic invertebrates and fishes, the effects of browning on macrophytes, invasive species, and food webs have been understudied. Research has focused on freshwater habitats without considering the fluxes between aquatic and terrestrial habitats. We highlight the importance of understanding how the changes in one habitat may cascade to another. Browning is a broader phenomenon than the heretofore concentration on the boreal region. Overall, we propose that future studies improve the ecological understanding of browning through the following research actions: 1) increasing our knowledge of ecological processes of browning in other wetland types than lakes and rivers, 2) assessing the impact of browning on aquatic food webs at multiple scales, 3) examining the effects of browning on aquatic-terrestrial habitat coupling, 4) expanding our knowledge of browning from the local to global scale, and 5) using remote sensing to examine browning and its ecological consequences.
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Affiliation(s)
- Clarisse C Blanchet
- Department of Biology, FI-20014, University of Turku, Finland; Department of Forest Sciences, P.O. Box 27, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Céline Arzel
- Department of Biology, FI-20014, University of Turku, Finland
| | - Aurélie Davranche
- CNRS UMR 6554 LETG, University of Angers, 2 Boulevard Lavoisier, FR-49000 Angers, France
| | - Kimmo K Kahilainen
- University of Helsinki, Lammi Biological Station, Pääjärventie 320, FI-16900 Lammi, Finland
| | - Jean Secondi
- University of Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France; Faculty of Sciences, University of Angers, F-49000 Angers, France
| | - Sami Taipale
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - Henrik Lindberg
- HAMK University of Applied Sciences, Forestry Programme, Saarelantie 1, FI-16970 Evo, Finland
| | - John Loehr
- University of Helsinki, Lammi Biological Station, Pääjärventie 320, FI-16900 Lammi, Finland
| | | | - Janne Sundell
- University of Helsinki, Lammi Biological Station, Pääjärventie 320, FI-16900 Lammi, Finland
| | - Mohamed Maanan
- UMR CNRS 6554, University of Nantes, F-44000 Nantes, France
| | - Petri Nummi
- Department of Forest Sciences, P.O. Box 27, University of Helsinki, FI-00014 Helsinki, Finland
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27
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Estlander S, Pippingsköld E, Horppila J. Artificial ditching of catchments and brownification-connected water quality parameters of lakes. WATER RESEARCH 2021; 205:117674. [PMID: 34597988 DOI: 10.1016/j.watres.2021.117674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/25/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
We studied the connections between lake water quality and the density of artificial ditching in lake catchments. Water color and the concentrations of dissolved organic carbon (DOC) and iron (Fe) in lake water increased with increasing ditch density. Additionally, the water color:DOC ratio increased along a ditch density gradient because ditching had a stronger effect on color than on DOC. This was mainly due to the positive effect of ditching on the Fe concentration in lakes. Color:DOC ratio was strongly dependent on Fe up to Fe concentrations of 1-1.5 mg L-1. Thus, the water color of lakes with Fe concentrations < 1 mg L-1 will respond especially strongly to the effects of catchment ditching. The effects of ditching were strongest in catchments with high peatland coverage due to their high ditch density and high storage of organic carbon and Fe. The long-lasting effects of ditching should be taken into account when studying the factors governing lake brownification.
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Affiliation(s)
- Satu Estlander
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014, Finland
| | - Ella Pippingsköld
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014, Finland
| | - Jukka Horppila
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014, Finland.
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28
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Eklöf K, von Brömssen C, Amvrosiadi N, Fölster J, Wallin MB, Bishop K. Brownification on hold: What traditional analyses miss in extended surface water records. WATER RESEARCH 2021; 203:117544. [PMID: 34419921 DOI: 10.1016/j.watres.2021.117544] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/06/2021] [Accepted: 08/07/2021] [Indexed: 06/13/2023]
Abstract
Widespread increases in organic matter (OM) content of surface waters, as measured by color and organic carbon (OC), are a major issue for aquatic ecosystems. Long-term monitoring programs revealed the issue of "brownification", with climate change, land cover changes and recovery from acidification all suspected to be major drivers or contributing factors. While many studies have focused on the impact and drivers, fewer have followed up on whether brownification is continuing. As time-series of OM data lengthen, conventional data-analysis approaches miss important information on when changes occur. To better identify temporal OM patterns during three decades (1990-2020) of systematic monitoring, we used generalized additive models to analyze 164 time-series from watercourses located across Sweden. Increases in OC that were widespread during 1990-2010 ceased a decade ago, and most color increases ceased 20 years ago. These findings highlight the need to reassess the understanding of brownification's spatial and temporal extent, as well as the tools used to analyze lengthening time series.
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Affiliation(s)
- Karin Eklöf
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden.
| | - Claudia von Brömssen
- Department of Energy and Technology, Applied Statistics and Mathematics, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden
| | - Nino Amvrosiadi
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden; Department of Bioeconomy and Health, Research Institutes of Sweden, Uppsala SE-75651, Sweden
| | - Jens Fölster
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden
| | - Marcus B Wallin
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden
| | - Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden
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29
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Klaus M, Karlsson J, Seekell D. Tree line advance reduces mixing and oxygen concentrations in arctic-alpine lakes through wind sheltering and organic carbon supply. GLOBAL CHANGE BIOLOGY 2021; 27:4238-4253. [PMID: 33960592 DOI: 10.1111/gcb.15660] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Oxygen depletion in lake bottom waters has adverse impacts on ecosystem health including decreased water quality from release of nutrients and reduced substances from sediments, and the reduction of fish growth and reproduction. Depletion occurs when oxygen is consumed during decomposition of organic matter, and oxygen replenishment is limited by water column stratification. Arctic-alpine lakes are often well mixed and oxygenated, but rapid climate change in these regions is an important driver of shifts in catchment vegetation that could affect the mixing and oxygen dynamics of lakes. Here, we analyze high-resolution time series of dissolved oxygen concentration and temperature profiles in 40 Swedish arctic-alpine lakes across the tree line ecotone. The lakes stratified for 1-125 days, and during stratification, near-bottom dissolved oxygen concentrations changed by -0.20 to +0.15 mg L-1 day-1 , resulting in final concentrations of 1.1-15.5 mg L-1 at the end of the longest stratification period. Structural equation modeling revealed that lakes with taller shoreline vegetation relative to lake area had higher dissolved organic carbon concentrations and oxygen consumption rates, but also lower wind speeds and longer stratification periods, and ultimately, lower near-bottom dissolved oxygen concentrations. We use an index of shoreline canopy height and lake area to predict variations among our study lakes in near-bottom dissolved oxygen concentrations at the end of the longest stratification period (R2 = 0.41). Upscaling this relationship to 8392 Swedish arctic-alpine lakes revealed that near-bottom dissolved oxygen concentrations drop below 3, 5, and 7 mg L-1 in 15%, 32%, and 53% of the lakes and that this proportion is sensitive (5%-22%, 13%-45%, and 29%-69%) to hypothetical tree line shifts observed in the past century or reconstructed for the Holocene (±200 m elevation; ±0.5° latitude). Assuming space-for-time substitution, we predict that tree line advance will decrease near-bottom dissolved oxygen concentrations in many arctic-alpine lakes.
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Affiliation(s)
- Marcus Klaus
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Jan Karlsson
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - David Seekell
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
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30
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Fontaine L, Khomich M, Andersen T, Hessen DO, Rasconi S, Davey ML, Eiler A. Multiple thresholds and trajectories of microbial biodiversity predicted across browning gradients by neural networks and decision tree learning. ISME COMMUNICATIONS 2021; 1:37. [PMID: 37938633 PMCID: PMC9723588 DOI: 10.1038/s43705-021-00038-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 08/20/2023]
Abstract
Ecological association studies often assume monotonicity such as between biodiversity and environmental properties although there is growing evidence that nonmonotonic relations dominate in nature. Here, we apply machine-learning algorithms to reveal the nonmonotonic association between microbial diversity and an anthropogenic-induced large-scale change, the browning of freshwaters, along a longitudinal gradient covering 70 boreal lakes in Scandinavia. Measures of bacterial richness and evenness (alpha-diversity) showed nonmonotonic trends in relation to environmental gradients, peaking at intermediate levels of browning. Depending on the statistical methods, variables indicative for browning could explain 5% of the variance in bacterial community composition (beta-diversity) when applying standard methods assuming monotonic relations and up to 45% with machine-learning methods taking non-monotonicity into account. This non-monotonicity observed at the community level was explained by the complex interchangeable nature of individual taxa responses as shown by a high degree of nonmonotonic responses of individual bacterial sequence variants to browning. Furthermore, the nonmonotonic models provide the position of thresholds and predict alternative bacterial diversity trajectories in boreal freshwater as a result of ongoing climate and land-use changes, which in turn will affect entire ecosystem metabolism and likely greenhouse gas production.
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Affiliation(s)
- Laurent Fontaine
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Maryia Khomich
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Tom Andersen
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dag O Hessen
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Serena Rasconi
- Université Savoie Mont Blanc, INRAE, CARRTEL, Thonon-les-Bains, France
| | - Marie L Davey
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Alexander Eiler
- Section for Aquatic Biology and Toxicology, Department of Biosciences, University of Oslo, Oslo, Norway.
- Center for Biogeochemistry in the Anthropocene, Department of Biosciences, University of Oslo, Oslo, Norway.
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Lepistö A, Räike A, Sallantaus T, Finér L. Increases in organic carbon and nitrogen concentrations in boreal forested catchments - Changes driven by climate and deposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 780:146627. [PMID: 34030343 DOI: 10.1016/j.scitotenv.2021.146627] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Brownification, caused by increasing dissolved organic carbon (DOC) concentrations is a threat to aquatic ecosystems over large areas in Europe. The increasing concentrations of DOC in northern boreal streams and lakes have attracted considerable attention with proposed important drivers such as climate, deposition and land-use, and complex interactions between them. Changes in total organic N (TON) concentrations have received less attention, even though carbon and nitrogen losses are highly related to each other. We used long-term (1990-2019) monitoring records of 12 small data-rich headwater forested catchments in a large gradient of climate and deposition. We found that total organic carbon (TOC) concentrations were significantly increasing in almost all study catchments. The mean air temperature and change in sulphate concentrations had a strong, significant correlation to TOC change-%. Both explained, alone, more than 65% of the change in TOC concentrations, and, together, up to 83% of the variation. Sulphur deposition has already decreased to low levels, our results indicate that its importance as a driver of TOC leaching has decreased but is still clearly detected, while the impact of climate warming as a driver of TOC leaching will be even more pronounced in the future. A positive correlation was found between drainage-% and increases in TON, suggesting also importance of land management. TON trends were tightly connected to changes in TOC, but not directly linked to decreasing S deposition.
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Affiliation(s)
- Ahti Lepistö
- Finnish Environment Institute SYKE, Latokartanonkaari 11, FI-00790 Helsinki, Finland.
| | - Antti Räike
- Finnish Environment Institute SYKE, Latokartanonkaari 11, FI-00790 Helsinki, Finland
| | - Tapani Sallantaus
- Finnish Environment Institute SYKE, Latokartanonkaari 11, FI-00790 Helsinki, Finland
| | - Leena Finér
- Natural Resources Institute Finland, Yliopistokatu 6b, FI 80 100 Joensuu, Finland
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32
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Eie M, Jensen TC, Walseng B, Eie AJ, Hessen DO. Long‐term resilience in microcrustacean communities despite environmental changes. Ecosphere 2021. [DOI: 10.1002/ecs2.3676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- M. Eie
- County Governor of Agder Box 788 Stoa Arendal 4809 Norway
| | - T. C. Jensen
- Norwegian Institute for Nature Research Sognsveien 68 Oslo 0855 Norway
| | - B. Walseng
- Norwegian Institute for Nature Research Sognsveien 68 Oslo 0855 Norway
| | | | - D. O. Hessen
- Department of Biosciences and Centre for Biogeochemistry in the Anthropocene University of Oslo Box 1066Blindern Oslo 0316 Norway
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Hall LJ, Emilson EJS, Edwards B, Watmough SA. Patterns and trends in lake concentrations of dissolved organic carbon in a landscape recovering from environmental degradation and widespread acidification. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:142679. [PMID: 33077226 DOI: 10.1016/j.scitotenv.2020.142679] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 05/27/2023]
Abstract
Concentrations of dissolved organic carbon (DOC) have increased in lakes throughout North America and Europe over the last three decades. Recovery from acid deposition and climate change have both been postulated as the primary mechanisms for the increase in DOC. To provide a clearer insight into the mechanisms responsible for increasing DOC we evaluated changes in lake and peat porewater chemistry collected in an area of approximately 33,000 km2 surrounding Sudbury, Ontario, a region undergoing dramatic recovery from acidic deposition. DOC concentrations varied considerably among the 44 lakes and over time (samples annually from 1981 to 2018), but the Sens Slope value showed a strong increase in lake DOC concentration over time, at 0.05 mg/ L y-1 (p < 0.001) that was related to increasing pH [0.03 units y-1, p < 0.001] and decreasing lake SO4 concentration [-0.24 mg/ L y-1; p < 0.001], but showed no relationship with temperature or precipitation. Similar strong relationships between DOC and pH (positive) and SO4 (negative) were observed in 18 peatlands sampled in the region. In a spatial analysis of 82 lakes sampled in 2018, concentrations of DOC in lakes were highest in flatter catchments with a greater wetland area, suggesting that wetlands are a major source of DOC in lakes. Optical properties of DOC obtained from extracts of wetland and upland soils at 6 catchments could be distinguished, primarily due to upland litter extracts having distinct optical properties from mineral soils or wetland soils. Optical properties of DOC in lakes however were inconsistent with those measured in soil extracts indicating that they are not useful for distinguishing DOC sources in these lakes. A predictive model was developed to explain DOC trends within Sudbury lakes using a stepwise linear regression combined with hierarchical partitioning to confirm the most influential processes on DOC. Almost 50% of the variability in DOC change in the 44 lakes was explained by the magnitude in lake pH change, catchment size and catchment sparse tree cover showing that recovery from acidic deposition is overwhelmingly responsible for increasing DOC in Sudbury lakes.
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Affiliation(s)
- L J Hall
- School of the Environment, Trent University, Peterborough, ON K9L 0G2, Canada
| | - E J S Emilson
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen St. E., Sault Ste. Marie, ON P6A 2E5, Canada
| | - B Edwards
- Ontario Ministry of Environment, Conservation and Parks, Vale Living with Lakes Centre, Laurentian University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada
| | - S A Watmough
- School of the Environment, Trent University, Peterborough, ON K9L 0G2, Canada.
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Abstract
Arctic and boreal regions are undergoing dramatic warming and also possess the world’s highest concentration of lakes. However, ecological changes in lakes are poorly understood. We present a continental-scale trend analysis of satellite lake color in the green wavelengths, which shows declining greenness from 1984 to 2019 in Arctic-boreal lakes across western North America. Annual 30-m Landsat composites indicate lake greenness has decreased by 15%. Our findings show a relationship between lake color, rising air temperatures, and increasing precipitation, supporting the theory that warming may be increasing connectivity between lakes and surrounding landscapes. Overall, our results bring a powerful set of observations in support of the hypothesis that lakes are sentinels for global change in rapidly warming Arctic-boreal ecosystems. The highest concentration of the world’s lakes are found in Arctic-boreal regions [C. Verpoorter, T. Kutser, D. A. Seekell, L. J. Tranvik, Geophys. Res. Lett. 41, 6396–6402 (2014)], and consequently are undergoing the most rapid warming [J. E. Overland et al., Arctic Report Card (2018)]. However, the ecological response of Arctic-boreal lakes to warming remains highly uncertain. Historical trends in lake color from remote sensing observations can provide insights into changing lake ecology, yet have not been examined at the pan-Arctic scale. Here, we analyze time series of 30-m Landsat growing season composites to quantify trends in lake greenness for >4 × 105 waterbodies in boreal and Arctic western North America. We find lake greenness declined overall by 15% from the first to the last decade of analysis within the 6.3 × 106-km2 study region but with significant spatial variability. Greening declines were more likely to be found in areas also undergoing increases in air temperature and precipitation. These findings support the hypothesis that warming has increased connectivity between lakes and the land surface [A. Bring et al., J. Geophys. Res. Biogeosciences 121, 621–649 (2016)], with implications for lake carbon cycling and energy budgets. Our study provides spatially explicit information linking climate to pan-Arctic lake color changes, a finding that will help target future ecological monitoring in remote yet rapidly changing regions.
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Lapierre J, Collins SM, Oliver SK, Stanley EH, Wagner T. Inconsistent browning of northeastern U.S. lakes despite increased precipitation and recovery from acidification. Ecosphere 2021. [DOI: 10.1002/ecs2.3415] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jean‐Francois Lapierre
- Département de sciences biologiques Université de Montréal Montréal QuébecH3C 3J7Canada
- Groupe de Recherche Interuniversitaire en Limnologie (GRIL) Université du Québec à Montréal Montréal QuebecH3C 3P8Canada
| | - Sarah M. Collins
- Department of Zoology and Physiology University of Wyoming Laramie Wyoming82701USA
- Program in Ecology University of Wyoming Laramie Wyoming82701USA
| | - Samantha K. Oliver
- U.S. Geological Survey Upper Midwest Water Science Center Middleton Wisconsin53562USA
| | - Emily H. Stanley
- Center for Limnology University of Wisconsin‐Madison Madison Wisconsin53706USA
| | - Tyler Wagner
- U.S. Geological Survey Pennsylvania Cooperative Fish and Wildlife Unit The Pennsylvania State University University Park Pennsylvania16802USA
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Nature's Role in Supporting Health during the COVID-19 Pandemic: A Geospatial and Socioecological Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18052227. [PMID: 33668228 PMCID: PMC7967714 DOI: 10.3390/ijerph18052227] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023]
Abstract
The COVID-19 pandemic has brought about unprecedented changes to human lifestyles across the world. The virus and associated social restriction measures have been linked to an increase in mental health conditions. A considerable body of evidence shows that spending time in and engaging with nature can improve human health and wellbeing. Our study explores nature's role in supporting health during the COVID-19 pandemic. We created web-based questionnaires with validated health instruments and conducted spatial analyses in a geographic information system (GIS). We collected data (n = 1184) on people's patterns of nature exposure, associated health and wellbeing responses, and potential socioecological drivers such as relative deprivation, access to greenspaces, and land-cover greenness. The majority of responses came from England, UK (n = 993). We applied a range of statistical analyses including bootstrap-resampled correlations and binomial regression models, adjusting for several potential confounding factors. We found that respondents significantly changed their patterns of visiting nature as a result of the COVID-19 pandemic. People spent more time in nature and visited nature more often during the pandemic. People generally visited nature for a health and wellbeing benefit and felt that nature helped them cope during the pandemic. Greater land-cover greenness within a 250 m radius around a respondent's postcode was important in predicting higher levels of mental wellbeing. There were significantly more food-growing allotments within 100 and 250 m around respondents with high mental wellbeing scores. The need for a mutually-advantageous relationship between humans and the wider biotic community has never been more important. We must conserve, restore and design nature-centric environments to maintain resilient societies and promote planetary health.
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Branfireun BA, Cosio C, Poulain AJ, Riise G, Bravo AG. Mercury cycling in freshwater systems - An updated conceptual model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 745:140906. [PMID: 32758756 DOI: 10.1016/j.scitotenv.2020.140906] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
The widely accepted conceptual model of mercury (Hg) cycling in freshwater lakes (atmospheric deposition and runoff of inorganic Hg, methylation in bottom sediments and subsequent bioaccumulation and biomagnification in biota) is practically accepted as common knowledge. There is mounting evidence that the dominant processes that regulate inputs, transformations, and bioavailability of Hg in many lakes may be missing from this picture, and the fixation on the temperate stratified lake archetype is impeding our exploration of understudied, but potentially important sources of methylmercury to freshwater lakes. In this review, the importance of understudied biogeochemical processes and sites of methylmercury production are highlighted, including the complexity of redox transformations of Hg within the lake system itself, the complex assemblage of microbes found in biofilms and periphyton (two vastly understudied important sources of methylmercury in many freshwater ecosystems), and the critical role of autochthonous and allochthonous dissolved organic matter which mediates the net supply of methylmercury from the cellular to catchment scale. A conceptual model of lake Hg in contrasting lakes and catchments is presented, highlighting the importance of the autochthonous and allochthonous supply of dissolved organic matter, bioavailable inorganic mercury and methylmercury and providing a framework for future convergent research at the lab and field scales to establish more mechanistic process-based relationships within and among critical compartments that regulate methylmercury concentrations in freshwater ecosystems.
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Affiliation(s)
- Brian A Branfireun
- Department of Biology and Centre for Environment & Sustainability, The University of Western Ontario, London, Canada.
| | - Claudia Cosio
- Université de Reims Champagne-Ardenne, UMR I-02 SEBIO, Reims, France
| | | | - Gunnhild Riise
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
| | - Andrea G Bravo
- Spanish National Research Council | CSIC, Institut de Ciències del Mar, Barcelona, Spain.
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38
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Kaste Ø, Austnes K, de Wit HA. Streamwater responses to reduced nitrogen deposition at four small upland catchments in Norway. AMBIO 2020; 49:1759-1770. [PMID: 32535875 PMCID: PMC7502627 DOI: 10.1007/s13280-020-01347-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/21/2020] [Accepted: 05/08/2020] [Indexed: 05/23/2023]
Abstract
Reduced emissions of nitrogen (N) in Europe have resulted in decreasing atmospheric deposition since 1990. Long-term data (1988-2017) from four small Norwegian catchments located along gradients in N deposition, rainfall, and organic carbon (C) show different responses to 25-30% reductions in N deposition during the same period. At three sites the decreased N deposition caused reduced leaching of nitrate to surface water, whereas the westernmost site showed no decrease, probably due to thin soils with low C:N ratio, poor vegetation cover and high precipitation. The loss of total N to streamwater constituted 30-50% of the N deposition. Losses via denitrification are unknown but assumed to be low, as a major fraction of the catchments are well-drained. Hence, the study sites seem to continue to accumulate N, presumably mostly in soil organic matter. Although atmospheric N deposition has declined, ambient loads might still exceed long-term sustainable levels in these vulnerable ecosystems.
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Affiliation(s)
- Øyvind Kaste
- Norwegian Institute for Water Research, Gaustadalleen 21, 0348 Oslo, Norway
- Centre for Coastal Research, University of Agder, PO box 422, 4604 Kristiansand, Norway
| | - Kari Austnes
- Norwegian Institute for Water Research, Gaustadalleen 21, 0348 Oslo, Norway
| | - Heleen A. de Wit
- Norwegian Institute for Water Research, Gaustadalleen 21, 0348 Oslo, Norway
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Deininger A, Kaste Ø, Frigstad H, Austnes K. Organic nitrogen steadily increasing in Norwegian rivers draining to the Skagerrak coast. Sci Rep 2020; 10:18451. [PMID: 33116239 PMCID: PMC7595164 DOI: 10.1038/s41598-020-75532-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 10/14/2020] [Indexed: 11/27/2022] Open
Abstract
Declining atmospheric nitrogen (N) deposition, through reduction in the direct input of inorganic N, may result in less inorganic N being leached from soils to freshwaters (dissolved inorganic N = DIN). Declining sulphur deposition, through reducing the ionic strength in soil water, increases the solubility and mobility of organic soil compounds and may result in increased leaching of organically bound N to freshwaters (total organic N = TON). It is unknown to which extent these two independents and opposing trends, i.e. DIN decline versus TON increase, may affect the nutrient balance (load, stoichiometry) of river water draining into coastal zones. By combining long-term atmospheric and riverine monitoring data of the five major Norwegian rivers draining to the Skagerrak coast, we show that over the past 27 years (1990-2017) river water nutrient composition, and specifically N stoichiometry has been steadily shifting from inorganic to organic fractions, with correlations to changes in human pressures (air pollution), but especially climate (precipitation, temperature, discharge). This shift in nutrient quality may have large consequences on the nutrient cycling in both freshwater and coastal ecosystems and illustrates the complex interactions of multiple stressors (here: N deposition, S deposition, and climate change) on aquatic ecosystems.
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Affiliation(s)
- A Deininger
- Centre for Coastal Research, University of Agder, Kristiansand, Norway.
- Norwegian Institute for Water Research (NIVA), Oslo, Norway.
| | - Ø Kaste
- Centre for Coastal Research, University of Agder, Kristiansand, Norway
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
| | - H Frigstad
- Centre for Coastal Research, University of Agder, Kristiansand, Norway
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
| | - K Austnes
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
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40
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Allesson L, Andersen T, Dörsch P, Eiler A, Wei J, Hessen DO. Phosphorus Availability Promotes Bacterial DOC-Mineralization, but Not Cumulative CO 2-Production. Front Microbiol 2020; 11:569879. [PMID: 33072029 PMCID: PMC7541949 DOI: 10.3389/fmicb.2020.569879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/25/2020] [Indexed: 11/13/2022] Open
Abstract
The current trend of increasing input of terrestrially derived dissolved organic carbon (DOC) to boreal freshwater systems is causing increased levels of carbon dioxide (CO2) supersaturation and degassing. Phosphorus (P) is often the most limiting nutrient for bacterial growth and would thus be expected to increase overall mineralization rates and CO2 production. However, high carbon (C) to P ratios of terrestrially derived DOC could also cause elevated cell-specific respiration of the excess C in heterotrophic bacteria. Using data from a survey of 75 Scandinavian lakes along an ecosystem gradient of DOC, we estimated in situ CO2 production rates. These rates showed a unimodal response with DOC-specific CO2 production negatively related to DOC:total phosphorus (TP) ratio, and a turning point at 5 mg C L-1, indicating higher DOC turnover rates in productive than in unproductive lakes. To further assess the dependency of bacterial respiration (BR) on DOC and P, we monitored CO2 production in incubations of water with a gradient of DOC crossed with two levels of inorganic P. Finally, we crossed DOC and P with a temperature gradient to test the temperature dependency of respiration rates [as oxygen (O2) consumption]. While total CO2 production seemed to be unaffected by P additions, respiration rates, and growth yields, as estimated by ribosomal gene copy numbers, suggest increased bacterial growth and decreased cell-specific respiration under non-limited P conditions. Respiration rates showed a sigmoid response to increasing DOC availability reaching a plateau at about 20 mg C L-1 of initial DOC concentrations. In addition to these P and DOC level effects, respiration rates responded in a non-monotonic fashion to temperature with an increase in respiration rates by a factor of 2.6 (±0.2) from 15 to 25°C and a decrease above 30°C. The combined results from the survey and experiments highlight DOC as the major determinant of CO2 production in boreal lakes, with P and temperature as significant modulators of respiration kinetics.
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Affiliation(s)
- Lina Allesson
- Department of Biosciences and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway
| | - Tom Andersen
- Department of Biosciences and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway
| | - Peter Dörsch
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Alexander Eiler
- Department of Biosciences and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway
| | - Jing Wei
- Department of Biosciences and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway
| | - Dag O Hessen
- Department of Biosciences and Centre for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway
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41
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Long-Term (2001–2020) Nutrient Transport from a Small Boreal Agricultural Watershed: Hydrological Control and Potential of Retention Ponds. WATER 2020. [DOI: 10.3390/w12102731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Agriculture contributes significantly to phosphorus and nitrogen loading in southern Finland. Climate change with higher winter air temperatures and precipitation may also promote loading increase further. We analyzed long-term nutrient trends (2001–2020) based on year-round weekly water sampling and daily weather data from a boreal small agricultural watershed. In addition, nutrient retention was studied in a constructed sedimentation pond system for two years. We did not find any statistically significant trends in weather conditions (temperature, precipitation, discharge, snow depth) except for an increase in discharge in March. Increasing trends in annual concentrations were found for nitrate, phosphate, and total phosphorus and total nitrogen. In fact, phosphate concentration increased in every season and nitrate concentration in other seasons except in autumn. Total phosphorus and total nitrogen concentrations increased in winter as well and total phosphorus also in summer. Increasing annual loading trend was found for total phosphorus, phosphate, and nitrate. Increasing winter loading was found for nitrate and total nitrogen, but phosphate loading increased in winter, spring, and summer. In the pond system, annual retention of total nitrogen was 1.9–4.8% and that of phosphorus 4.3–6.9%. In addition, 25–40% of suspended solids was sedimented in the ponds. Our results suggest that even small ponds can be utilized to decrease nutrient and material transport, but their retention efficiency varies between years. We conclude that nutrient loading from small boreal agricultural catchments, especially in wintertime, has already increased and is likely to increase even further in the future due to climate change. Thus, the need for new management tools to reduce loading from boreal agricultural lands becomes even more acute.
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42
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Freeman EC, Creed IF, Jones B, Bergström AK. Global changes may be promoting a rise in select cyanobacteria in nutrient-poor northern lakes. GLOBAL CHANGE BIOLOGY 2020; 26:4966-4987. [PMID: 32445590 DOI: 10.1111/gcb.15189] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 04/09/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
The interacting effects of global changes-including increased temperature, altered precipitation, reduced acidification and increased dissolved organic matter loads to lakes-are anticipated to create favourable environmental conditions for cyanobacteria in northern lakes. However, responses of cyanobacteria to these global changes are complex, if not contradictory. We hypothesized that absolute and relative biovolumes of cyanobacteria (both total and specific genera) are increasing in Swedish nutrient-poor lakes and that these increases are associated with global changes. We tested these hypotheses using data from 28 nutrient-poor Swedish lakes over 16 years (1998-2013). Increases in cyanobacteria relative biovolume were identified in 21% of the study sites, primarily in the southeastern region of Sweden, and were composed mostly of increases from three specific genera: Merismopedia, Chroococcus and Dolichospermum. Taxon-specific changes were related to different environmental stressors; that is, increased surface water temperature favoured higher Merismopedia relative biovolume in low pH lakes with high nitrogen to phosphorus ratios, whereas acidification recovery was statistically related to increased relative biovolumes of Chroococcus and Dolichospermum. In addition, enhanced dissolved organic matter loads were identified as potential determinants of Chroococcus suppression and Dolichospermum promotion. Our findings highlight that specific genera of cyanobacteria benefit from different environmental changes. Our ability to predict the risk of cyanobacteria prevalence requires consideration of the environmental condition of a lake and the sensitivities of the cyanobacteria genera within the lake. Regional patterns may emerge due to spatial autocorrelations within and among lake history, rates and direction of environmental change and the niche space occupied by specific cyanobacteria.
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Affiliation(s)
- Erika C Freeman
- Department of Geography, Western University, London, ON, Canada
| | - Irena F Creed
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada
| | - Blake Jones
- Department of Electrical and Computer Engineering, Western University, London, ON, Canada
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43
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Meyer-Jacob C, Labaj AL, Paterson AM, Edwards BA, Keller WB, Cumming BF, Smol JP. Re-browning of Sudbury (Ontario, Canada) lakes now approaches pre-acid deposition lake-water dissolved organic carbon levels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 725:138347. [PMID: 32304963 DOI: 10.1016/j.scitotenv.2020.138347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/20/2020] [Accepted: 03/29/2020] [Indexed: 06/11/2023]
Abstract
Since the implementation of large-scale lake monitoring in the ~1980s, water color and dissolved organic carbon (DOC) concentrations have increased in many northern lakes (i.e., lake browning), impacting the functioning of aquatic ecosystems. In regions that formerly experienced high levels of acid deposition, this browning trend has been largely attributed to the recovery from the impacts of past acid deposition. However, the extent to which DOC levels have now returned to naturally higher, pre-industrial conditions is still poorly understood. In this study, we assessed whether DOC levels are still influenced by acid deposition in lakes near Sudbury, Ontario, a region that has been heavily affected by sulfur dioxide emissions from local metal smelting during the 20th century. We analyzed water chemistry monitoring data (1981-2018), together with comparisons between modern and pre-industrial DOC levels inferred from sediment spectroscopy, for 51 acid-sensitive and 24 buffered reference lakes across the Sudbury landscape. Since 1981, DOC concentrations doubled in acid-sensitive lakes, with a mean increase of +1.6 mg/L, whereas in more buffered reference lakes, mean DOC levels increased by only 0.8 mg/L. Similarly, sediment-inferred DOC trends indicate that current DOC levels are, on average, ~22% below pre-industrial levels in acid sensitive systems compared to only ~10% in buffered lakes. Weakening correlations between DOC and acidification-related water chemistry variables (e.g., pH, alkalinity, metals) further indicate a diminishing influence of acid deposition on DOC in Sudbury lakes. These results highlight the strong impact that acid deposition has historically had on lake-water DOC dynamics in this region, but also suggest that DOC levels are approaching natural baseline levels in less acid-sensitive lakes, and that other drivers, such as changes in climate or vegetation cover, are now becoming the dominant controls on changes in DOC concentrations.
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Affiliation(s)
- Carsten Meyer-Jacob
- Paleoecological Environmental Assessment and Research Lab, Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada; Department of Ecology and Environmental Science, Umeå University, 90187 Umeå, Sweden.
| | - Andrew L Labaj
- Paleoecological Environmental Assessment and Research Lab, Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Andrew M Paterson
- Dorset Environmental Science Centre, Ontario Ministry of the Environment, Conservation and Parks, Dorset, ON P0A 1E0, Canada
| | - Brie A Edwards
- Ontario Ministry of the Environment, Conservation and Parks, Cooperative Freshwater Ecology Unit, Vale Living with Lakes Centre, Laurentian University, Sudbury, ON P3E 2C6, Canada
| | - Wendel Bill Keller
- Cooperative Freshwater Ecology Unit, Vale Living with Lakes Centre, Laurentian University, Sudbury, ON P3E 2C6, Canada
| | - Brian F Cumming
- Paleoecological Environmental Assessment and Research Lab, Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
| | - John P Smol
- Paleoecological Environmental Assessment and Research Lab, Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
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44
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Olmanson LG, Page BP, Finlay JC, Brezonik PL, Bauer ME, Griffin CG, Hozalski RM. Regional measurements and spatial/temporal analysis of CDOM in 10,000+ optically variable Minnesota lakes using Landsat 8 imagery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 724:138141. [PMID: 32247976 DOI: 10.1016/j.scitotenv.2020.138141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/20/2020] [Accepted: 03/21/2020] [Indexed: 06/11/2023]
Abstract
Information on colored dissolved organic matter (CDOM) is essential for understanding and managing lakes but is often not available, especially in lake-rich regions where concentrations are often highly variable in time and space. We developed remote sensing methods that can use both Landsat and Sentinel satellite imagery to provide census-level CDOM measurements across the state of Minnesota, USA, a lake-rich landscape with highly varied lake, watershed, and climatic conditions. We evaluated the error of satellite derived CDOM resulting from two atmospheric correction methods with in situ data, and found that both provided substantial improvements over previous methods. We applied CDOM models to 2015 and 2016 Landsat 8 OLI imagery to create 2015 and 2016 Minnesota statewide CDOM maps (reported as absorption coefficients at 440 nm, a440) and used those maps to conduct a geospatial analysis at the ecoregion level. Large differences in a440 among ecoregions were related to predominant land cover/use; lakes in ecoregions with large areas of wetland and forest had significantly higher CDOM levels than lakes in agricultural ecoregions. We compared regional lake CDOM levels between two years with strongly contrasting precipitation (close-to-normal precipitation year in 2015 and much wetter conditions with large storm events in 2016). CDOM levels of lakes in agricultural ecoregions tended to decrease between 2015 and 2016, probably because of dilution by rainfall, and 7% of lakes in these areas decreased in a440 by ≥3 m-1. In two ecoregions with high forest and wetlands cover, a440 increased by >3 m-1 in 28 and 31% of the lakes, probably due to enhanced transport of CDOM from forested wetlands. With appropriate model tuning and validation, the approach we describe could be extended to other regions, providing a method for frequent and comprehensive measurements of CDOM, a dynamic and important variable in surface waters.
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Affiliation(s)
- Leif G Olmanson
- Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA.
| | - Benjamin P Page
- Water Resources Center, University of Minnesota, St. Paul, MN 55108, USA
| | - Jacques C Finlay
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA
| | - Patrick L Brezonik
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Marvin E Bauer
- Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA
| | - Claire G Griffin
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA; Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22905, USA
| | - Raymond M Hozalski
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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Zheng T, Cao Y, Peng J, Bai X, Chen X. Effects of climate warming and nitrogen deposition on subtropical montane ponds (central China) over the last two centuries: Evidence from subfossil chironomids. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 262:114256. [PMID: 32126441 DOI: 10.1016/j.envpol.2020.114256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/17/2020] [Accepted: 02/21/2020] [Indexed: 06/10/2023]
Abstract
Many remote montane ecosystems are experiencing biogeochemical changes driven by warming climate and atmospheric pollution. Compared with circumpolar and temperate lakes, the responses of subtropical montane lakes to these external stressors have been less investigated. Here we present sedimentary multi-proxies records (i.e. chironomids, elements and stable isotope of carbon and nitrogen) in 210Pb-dated cores from two montane ponds (central China). Before the 1900s, low biomass and the dominance of opportunistic species (e.g. Chironomus anthracinus-type) in both ponds might be in response to cold and harsh condition. Thereafter, chironomid communities in both ponds experienced pronounced shifts. Nutrient-tolerant/warm-adapted species (e.g. Chironomus sp., Polypedilum nubeculosum-type and Endochironomus impar-type) proliferated and biomass increased synchronously after the 1900s, suggestive of favorable condition for chironomid growth. Redundancy analyses revealed that changes in chironomid communities in both ponds were significantly correlated with rising temperature and δ15N depletion. Prolonged growing season and nitrogen subsidy would increase primary productivity, and hence enhancing food availability for chironomids. Catchment-mediated indirect effects of warming and nitrogen deposition, such as hydrological changes and terrestrial organic matter inputs, would impose further influences on chironomid communities. Taken together, the combined effects of climate warming and nitrogen deposition have caused significant shifts in primary consumers of these montane ponds, and imposed cascading effects on structure and function of subtropical montane aquatic ecosystems.
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Affiliation(s)
- Ting Zheng
- Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China
| | - Yanmin Cao
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan, 430074, China
| | - Jia Peng
- Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China
| | - Xue Bai
- Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China
| | - Xu Chen
- Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China.
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Saulnier-Talbot É, Antoniades D, Pienitz R. Hotspots of biotic compositional change in lakes along vast latitudinal transects in northern Canada. GLOBAL CHANGE BIOLOGY 2020; 26:2270-2279. [PMID: 31995661 DOI: 10.1111/gcb.15016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/11/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
Ecotones mark zones of rapid change in ecological structure at various spatial scales. They are believed to be particularly susceptible to shifts caused by environmental transformation, making them key regions for studying the effects of global change. Here, we explored the variation in assemblage structure of aquatic primary producer and consumer communities across latitudinal transects in northeastern North America (Québec-Labrador) to identify spatial patterns in biodiversity that indicated the location of transition zones across the landscape. We analyzed species richness and the cumulative rate of compositional change (expressed as beta-diversity) of diatoms and chironomids to detect any abrupt shifts in the rate of spatial taxonomic turnover. We used principal coordinates analysis to estimate community turnover with latitude, then applied piecewise linear regression to assess the position of ecotones. Statistically significant changes in assemblage composition occurred at 52 and 55°N, corresponding to the transition between closed- and open-crown forest, and to the southern onset of the forest tundra (i.e., the forest limit), respectively. The spatial distribution of ecotones was most strongly related to air temperature for chironomids and to vegetation- and soil-related chemical attributes of lake water for diatoms, including dissolved organic carbon content and water color. Lakes at mid- to high-latitudes currently face pressures from rapidly rising temperatures, accompanied by large increases in organic carbon inputs from their catchments, often leading to browning and its associated effects. The biota at the base of food webs in lakes located in transition zones are disproportionately affected by the cascading effects of these multi-factorial changes, concurrent with pronounced terrestrial greening observed in these regions. Similar patterns of biotic shifts have been observed along alpine aquatic transects, indicating the potential for widespread restructuring of cold, high-altitude and high-latitude freshwater communities due to global change.
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Affiliation(s)
- Émilie Saulnier-Talbot
- Laboratoire de paléoécologie aquatique (LPA), Département de géographie and Centre d'études nordiques (CEN: Centre for Northern Studies), Université Laval, Québec, QC, Canada
| | - Dermot Antoniades
- Laboratoire de paléoécologie aquatique (LPA), Département de géographie and Centre d'études nordiques (CEN: Centre for Northern Studies), Université Laval, Québec, QC, Canada
| | - Reinhard Pienitz
- Laboratoire de paléoécologie aquatique (LPA), Département de géographie and Centre d'études nordiques (CEN: Centre for Northern Studies), Université Laval, Québec, QC, Canada
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47
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Škerlep M, Steiner E, Axelsson A, Kritzberg ES. Afforestation driving long-term surface water browning. GLOBAL CHANGE BIOLOGY 2020; 26:1390-1399. [PMID: 31667991 PMCID: PMC7079054 DOI: 10.1111/gcb.14891] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/22/2019] [Indexed: 05/22/2023]
Abstract
Increase in surface water color (browning), caused by rising dissolved organic carbon (DOC) and iron concentrations, has been widely reported and studied in the last couple of decades. This phenomenon has implications to aquatic ecosystem function and biogeochemical carbon cycling. While recovery from acidification and changes in climate-related variables, such as precipitation and length of growing season, are recognized as drivers behind browning, land-use change has received less attention. In this study, we include all of the above factors and aim to discern their individual and combined contribution to water color variation in an unprecedentedly long (1940-2016) and highly resolved dataset (~20 times per month), from a river in southern Sweden. Water color showed high seasonal variability and a marked long-term increase, particularly in the latter half of the dataset (~1980). Short-term and seasonal variations were best explained by precipitation, with temperature playing a secondary role. All explanatory variables (precipitation, temperature, S deposition, and land-use change) contributed significantly and together predicted 75% of the long-term variation in water color. Long-term change was best explained by a pronounced increase in Norway spruce (Picea abies Karst) volume-a measure of land-use change and a proxy for buildup of organic soil layers-and by change in atmospheric S deposition. When modeling water color with a combination of explanatory variables, Norway spruce showed the highest contribution to explaining long-term variability. This study highlights the importance of considering land-use change as a factor behind browning and combining multiple factors when making predictions in water color and DOC.
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Affiliation(s)
| | | | - Anna‐Lena Axelsson
- Department of Forest Resource ManagementSwedish University of Agricultural SciencesUmeåSweden
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Kritzberg ES, Hasselquist EM, Škerlep M, Löfgren S, Olsson O, Stadmark J, Valinia S, Hansson LA, Laudon H. Browning of freshwaters: Consequences to ecosystem services, underlying drivers, and potential mitigation measures. AMBIO 2020; 49:375-390. [PMID: 31367885 PMCID: PMC6965042 DOI: 10.1007/s13280-019-01227-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/03/2019] [Accepted: 07/10/2019] [Indexed: 05/05/2023]
Abstract
Browning of surface waters, as a result of increasing dissolved organic carbon and iron concentrations, is a widespread phenomenon with implications to the structure and function of aquatic ecosystems. In this article, we provide an overview of the consequences of browning in relation to ecosystem services, outline what the underlying drivers and mechanisms of browning are, and specifically focus on exploring potential mitigation measures to locally counteract browning. These topical concepts are discussed with a focus on Scandinavia, but are of relevance also to other regions. Browning is of environmental concern as it leads to, e.g., increasing costs and risks for drinking water production, and reduced fish production in lakes by limiting light penetration. While climate change, recovery from acidification, and land-use change are all likely factors contributing to the observed browning, managing the land use in the hydrologically connected parts of the landscape may be the most feasible way to counteract browning of natural waters.
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Affiliation(s)
- Emma S. Kritzberg
- Biology Department, Lund University, Ecology Building, Sölvegatan 37, 223 62 Lund, Sweden
| | - Eliza Maher Hasselquist
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Skogsmarksgränd, 901 83 Umeå, Sweden
| | - Martin Škerlep
- Biology Department, Lund University, Ecology Building, Sölvegatan 37, 223 62 Lund, Sweden
| | - Stefan Löfgren
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), P.O. Box 7050, 750 07 Uppsala, Sweden
| | - Olle Olsson
- Stockholm Environment Institute, Linnégatan 87D, P.O. Box 242 18, 104 51 Stockholm, Sweden
| | - Johanna Stadmark
- IVL Svenska Miljöinstitutet, Box 530 21, 400 14 Göteborg, Sweden
| | | | - Lars-Anders Hansson
- Biology Department, Lund University, Ecology Building, Sölvegatan 37, 223 62 Lund, Sweden
| | - Hjalmar Laudon
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Skogsmarksgränd, 901 83 Umeå, Sweden
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49
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Xiao Y, Rohrlack T, Riise G. Unraveling long-term changes in lake color based on optical properties of lake sediment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 699:134388. [PMID: 33736194 DOI: 10.1016/j.scitotenv.2019.134388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 09/06/2019] [Accepted: 09/08/2019] [Indexed: 06/12/2023]
Abstract
A number of boreal surface waters have become browner over the last two decades. Recovery from acid rain is regarded as an important driver for this lake color increase, indicating a general browner lake color in preindustrial times. However, the lack of long-term monitoring data makes it challenging to unravel historical changes in lake color. In this study, we estimated long-term development in lake color (1800 to 2015) based on the optical properties of alkaline extractable dissolved organic matter (DOM) from sediment using UV-Vis and fluorescence spectroscopy. We found that the present lake color (2015) was significantly browner (four times higher in absorption coefficient) than for the period from 1800 to 1915 when lake color was at a lower and more stable level. Fluorescence excitation-emission matrices combined with parallel factor analysis (EEM-PARAFAC) indicate that terrestrially derived DOM was the main source of sediment DOM. However, the importance of in-lake source of DOM has significantly increased with time. The long-term trend in DOM burial was not consistent with the anthropogenic sulfur (S) deposition pattern. However, along with the increased sediment DOM, there has been increased precipitation, temperature and forest growth with time, which affect the production and degradation of DOM. Even though S deposition might have delayed the runoff of terrestrial DOM for a certain period, it comes in addition to other color-regulating factors. Thus, there is no single driver for the observed lake browning, but rather an interplay between different drivers varying in strength over time, such as afforestation, changes in areal use, declined S deposition, and increased temperature and precipitation.
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Affiliation(s)
- Yihua Xiao
- Department of Biological and Environmental Science, University of Jyväskylä, FI-40014 Jyväskylä, Finland; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway.
| | - Thomas Rohrlack
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway.
| | - Gunnhild Riise
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway.
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50
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Meyer-Jacob C, Michelutti N, Paterson AM, Cumming BF, Keller WB, Smol JP. The browning and re-browning of lakes: Divergent lake-water organic carbon trends linked to acid deposition and climate change. Sci Rep 2019; 9:16676. [PMID: 31723150 PMCID: PMC6853936 DOI: 10.1038/s41598-019-52912-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 10/24/2019] [Indexed: 11/15/2022] Open
Abstract
Dissolved organic carbon (DOC) concentrations and water colour are increasing in many inland waters across northern Europe and northeastern North America. This inland-water “browning” has profound physical, chemical and biological repercussions for aquatic ecosystems affecting water quality, biological community structures and aquatic productivity. Potential drivers of this “browning” trend are complex and include reductions in atmospheric acid deposition, changes in land use/cover, increased nitrogen deposition and climate change. However, because of the overlapping impacts of these stressors, their relative contributions to DOC dynamics remain unclear, and without appropriate long-term monitoring data, it has not been possible to determine whether the ongoing “browning” is unprecedented or simply a “re-browning” to pre-industrial DOC levels. Here, we demonstrate the long-term impacts of acid deposition and climate change on lake-water DOC concentrations in low and high acid-deposition areas using infrared spectroscopic techniques on ~200-year-long lake-sediment records from central Canada. We show that acid deposition suppressed naturally higher DOC concentrations during the 20th century, but that a “re-browning” of lakes is now occurring with emissions reductions in formerly high deposition areas. In contrast, in low deposition areas, climate change is forcing lakes towards new ecological states, as lake-water DOC concentrations now often exceed pre-industrial levels.
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Affiliation(s)
- Carsten Meyer-Jacob
- Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston, ON, K7L 3J9, Canada. .,Department of Ecology and Environmental Science, Umeå University, 90187, Umeå, Sweden.
| | - Neal Michelutti
- Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston, ON, K7L 3J9, Canada
| | - Andrew M Paterson
- Dorset Environmental Science Centre, Ontario Ministry of the Environment, Conservation and Parks, Dorset, ON, P0A 1E0, Canada
| | - Brian F Cumming
- Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston, ON, K7L 3J9, Canada
| | - Wendel Bill Keller
- Cooperative Freshwater Ecology Unit, Vale Living with Lakes Centre, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - John P Smol
- Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston, ON, K7L 3J9, Canada
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