1
|
Kopáček J, Brahney J, Kaňa J, Kopáček M, Porcal P, Stuchlík E. The concentration of organic nitrogen in mountain lakes is increasing as a result of reduced acid deposition and climate change. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175363. [PMID: 39117205 DOI: 10.1016/j.scitotenv.2024.175363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/28/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
The ionic and nutrient composition of mountain lakes recovering from atmospheric acidification is increasingly influenced by climate change (increasing air temperature and frequency of heavy rainfall events). We investigated the evolution of organic nitrogen (ON), dissolved organic carbon (DOC) and phosphorus (P) concentrations in alpine lakes in the Tatra Mountains (Central Europe) between 1993 and 2023, resulting from changes in climate and the ionic composition of atmospheric deposition. Our results suggest that the decreasing acidity of precipitation and the climatically induced increasing frequency of heavy rainfall events and air temperatures fluctuating around the freezing point have the potential to increase ON concentrations in alpine lakes despite decreasing deposition of inorganic N. The increasing ON involves its allochthonous and autochthonous sources: (1) increased co-export of ON with DOC from soils in dissolved organic matter due to less acidic precipitation and more frequent heavy rainfall events and (2) increased in-lake primary productivity (chlorophyll a) associated with higher P availability. Based on our previous studies, we hypothesize that P availability has increased due to (i) reduced adsorption of phosphate in precipitation to the metal hydroxides in the soil-adsorption complex as a result of increasing pH in precipitation and soil water and (ii) increased P production by weathering due to climate-induced increased mechanical erosion of rocks in unstable scree areas. The extent of these changes was related to the percentage cover of scree areas and meadow soils in the lake catchments. In addition, our results suggest that ON (besides chlorophyll a) may be a more sensitive indicator of increasing productivity of oligotrophic alpine lakes under changing air pollution and climate than generally low P concentrations and their poorly detectable trends.
Collapse
Affiliation(s)
- Jiří Kopáček
- Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 370 05 České Budějovice, Czech Republic; University of South Bohemia, Faculty of Science, CZ-370 05 České Budějovice, Czech Republic.
| | - Janice Brahney
- Utah State University, Department of Watershed Sciences and Ecology Center, 5210 Old Main Hill, Logan, UT 84322, USA.
| | - Jiří Kaňa
- Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 370 05 České Budějovice, Czech Republic; University of South Bohemia, Faculty of Science, CZ-370 05 České Budějovice, Czech Republic.
| | - Marek Kopáček
- Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 370 05 České Budějovice, Czech Republic; University of South Bohemia, Faculty of Science, CZ-370 05 České Budějovice, Czech Republic.
| | - Petr Porcal
- Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 370 05 České Budějovice, Czech Republic; University of South Bohemia, Faculty of Science, CZ-370 05 České Budějovice, Czech Republic.
| | - Evžen Stuchlík
- Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 370 05 České Budějovice, Czech Republic.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Monteith DT, Henrys PA, Hruška J, de Wit HA, Krám P, Moldan F, Posch M, Räike A, Stoddard JL, Shilland EM, Pereira MG, Evans CD. Long-term rise in riverine dissolved organic carbon concentration is predicted by electrolyte solubility theory. SCIENCE ADVANCES 2023; 9:eade3491. [PMID: 36652511 PMCID: PMC9848639 DOI: 10.1126/sciadv.ade3491] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
The riverine dissolved organic carbon (DOC) flux is of similar magnitude to the terrestrial sink for atmospheric CO2, but the factors controlling it remain poorly determined and are largely absent from Earth system models (ESMs). Here, we show, for a range of European headwater catchments, that electrolyte solubility theory explains how declining precipitation ionic strength (IS) has increased the dissolution of thermally moderated pools of soluble soil organic matter (OM), while hydrological conditions govern the proportion of this OM entering the aquatic system. Solubility will continue to rise exponentially with declining IS until pollutant ion deposition fully flattens out under clean air policies. Future DOC export will increasingly depend on rates of warming and any directional changes to the intensity and seasonality of precipitation and marine ion deposition. Our findings provide a firm foundation for incorporating the processes dominating change in this component of the global carbon cycle in ESMs.
Collapse
Affiliation(s)
- Donald T. Monteith
- UK Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | - Peter A. Henrys
- UK Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | - Jakub Hruška
- Czech Geological Survey, Klárov 3, 11821 Prague, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic
| | - Heleen A. de Wit
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
- Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, Section for Aquatic Biology and Toxicology, University of Oslo, Oslo, Norway
| | - Pavel Krám
- Czech Geological Survey, Klárov 3, 11821 Prague, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic
| | - Filip Moldan
- IVL Swedish Environmental Research Institute, Box 530 21, 400 14 Göteborg, Sweden
| | - Maximilian Posch
- International Institute for Applied Systems Analysis (IIASA), A-2361 Laxenburg, Austria
| | - Antti Räike
- Finnish Environment Institute (SYKE), P.O.Box 140, FI-00790 Helsinki, Finland
| | | | - Ewan M. Shilland
- Environmental Change Research Centre, UCL, Gower Street, London WC1E 6BT, UK
- Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - M. Gloria Pereira
- UK Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK
| | - Chris D. Evans
- UK Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, LL57 2UW, UK
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
de Wit HA, Stoddard JL, Monteith DT, Sample JE, Austnes K, Couture S, Fölster J, Higgins SN, Houle D, Hruška J, Krám P, Kopacek J, Paterson AM, Valinia S, Van Dam H, Vuorenmaa J, Evans CD. Cleaner air reveals growing influence of climate on dissolved organic carbon trends in northern headwaters. ENVIRONMENTAL RESEARCH LETTERS : ERL [WEB SITE] 2021; 16:1-13. [PMID: 35874907 PMCID: PMC9306449 DOI: 10.1088/1748-9326/ac2526] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface water browning, the result of increasing concentrations of dissolved organic matter (DOM), has been widespread in northern ecosystems in recent decades. Here, we assess a database of 426 undisturbed headwater lakes and streams in Europe and North America for evidence of trends in DOM between 1990 and 2016. We describe contrasting changes in DOM trends in Europe (decelerating) and North America (accelerating), which are consistent with organic matter solubility responses to declines in sulfate deposition. While earlier trends (1990-2004) were almost entirely related to changes in atmospheric chemistry, climatic and chemical drivers were equally important in explaining recent DOM trends (2002-2016). We estimate that riverine DOM export from northern ecosystems increased by 27% during the study period. Increased summer precipitation strengthened upward dissolved organic carbon trends while warming apparently damped browning. Our results suggest strong but changing influences of air quality and climate on the terrestrial carbon cycle, and on the magnitude of carbon export from land to water.
Collapse
Affiliation(s)
- Heleen A de Wit
- Norwegian Institute for Water Research, N-0349 Oslo, Norway
- Centre for Biogeochemistry in the Anthropocene, University of Oslo, N-0315 Oslo, Norway
| | | | - Donald T Monteith
- UK Centre for Ecology and Hydrology, Lancaster Environment Centre, LA1 4AP Bailrigg, Lancaster, United Kingdom
| | - James E Sample
- Norwegian Institute for Water Research, N-0349 Oslo, Norway
| | - Kari Austnes
- Norwegian Institute for Water Research, N-0349 Oslo, Norway
| | - Suzanne Couture
- Environment and Climate Change Canada (ECCC), Montreal, QC H2Y 2E7, Canada
| | - Jens Fölster
- Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | | | - Daniel Houle
- Environment and Climate Change Canada (ECCC), Montreal, QC H2Y 2E7, Canada
| | - Jakub Hruška
- Czech Geological Survey, 152 00 Prague, Czech Republic
- Global Change Research Institute, CAS, 603 00 Brno, Czech Republic
| | - Pavel Krám
- Czech Geological Survey, 152 00 Prague, Czech Republic
- Global Change Research Institute, CAS, 603 00 Brno, Czech Republic
| | - Jiří Kopacek
- Biology Centre, CAS, Institute of Hydrobiology, 37005 Ceske Budejovice, Czech Republic
| | - Andrew M Paterson
- Dorset Environmental Science Centre, Ontario Ministry of the Environment, Conservation and Parks, Dorset, ON, Canada
| | - Salar Valinia
- Norwegian Institute for Water Research, N-0349 Oslo, Norway
- Swedish Environmental Protection Agency, 106 42 Stockholm, Sweden
| | - Herman Van Dam
- Consultancy for Water and Nature, NL-1034 WR, Amsterdam, The Netherlands
| | | | - Chris D Evans
- Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
- UK Centre for Ecology and Hydrology, LL57 2UW Bangor, United Kingdom
| |
Collapse
|
7
|
Redden D, Trueman BF, Dunnington DW, Anderson LE, Gagnon GA. Chemical recovery and browning of Nova Scotia surface waters in response to declining acid deposition. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:446-456. [PMID: 33565526 DOI: 10.1039/d0em00425a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Declining emissions of sulfur and nitrogen have curtailed acid deposition across large areas of North America and Europe. This has allowed many lakes to recover from acidification, with decreases in sulfate, increases in pH, and increases in alkalinity. But reduced acid deposition has not always coincided with chemical lake recovery. Surface waters in Nova Scotia did not exhibit clear evidence of recovery as recently as 2007, due in part to increasing organic acidity and slow replenishment of base cations. In an updated assessment with data collected as recently as 2019, we analyze water chemistry representing 81 lakes and rivers and two precipitation monitoring stations over up to 41 years. We find that Nova Scotia surface waters are now exhibiting signs of chemical recovery. We estimated the linear decrease in precipitation sulfate and nitrate yield at up to 0.31 and 0.18 kg ha-1 year-2, respectively, and the linear increase in precipitation pH at up to 0.014 year-1. Sulfate decreased in 60 of 62 lakes and 14 of 17 rivers (-0.0051 to -0.23 mg L-1 year-1), while pH increased in 55 of 64 lakes and 11 of 17 rivers (0.0015-0.072 year-1). Apparent colour increased in 54 of 62 lakes and 13 of 17 rivers (0.0026-3.9 Pt-Co year-1). We identified increasing aluminum trends in 46 of 61 lakes, and we show using size-exclusion chromatography that binding to organic and iron-based colloids may help to explain these trends. To the extent that increases in apparent colour are explained by chromophoric dissolved organic matter (DOM), they imply greater binding capacity for metals in surface waters, and greater capacity for DOM to stabilize metal (oxyhydr)oxide colloids.
Collapse
Affiliation(s)
- D Redden
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia B3H 4R2, Canada.
| | | | | | | | | |
Collapse
|
8
|
Wasswa J, Driscoll CT, Zeng T. Photochemical Characterization of Surface Waters from Lakes in the Adirondack Region of New York. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10654-10667. [PMID: 32786602 DOI: 10.1021/acs.est.0c02811] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The Adirondack Mountain region of New York, a historical hotspot for atmospheric sulfur and nitrogen deposition, features abundant lakes that are experiencing browning associated with recovery from acidification. Yet, much remains unknown about the photoreactivity of Adirondack lake waters. We quantified the apparent quantum yields (Φapp,RI) of photochemically produced reactive intermediates (RIs), such as excited triplet states of dissolved organic matter (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH), for surface waters collected from 16 representative Adirondack lakes. Φapp,3DOM* and Φapp,1O2 for native Adirondack lake waters fell within ranges reported for whole waters and DOM isolates from various sources, while Φapp,•OH were substantially lower than those measured for other aquatic samples. Orthogonal partial least squares and multiple linear regression analyses identified the spectral slope coefficient from 290 to 400 nm (S290-400) as the most effective predictor of Φapp,RI among measured water chemistry parameters and bulk DOM properties. Φapp,RI also exhibited divergent responses to controlled pH adjustment and aluminum or iron addition simulating hypothetical scenarios relevant to past and future water chemistry conditions of Adirondack lakes. This study highlights the need for continued research on changes in photoreactivity of acid-impacted aquatic ecosystems in response to browning and subsequent impacts on photochemical processes.
Collapse
Affiliation(s)
- Joseph Wasswa
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| | - Teng Zeng
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| |
Collapse
|
9
|
Lei L, Thompson JA, McDonald LM. Assessment of dissolved organic carbon and iron effects on water color between a forest and pasture-dominated fine-scale catchment in a Central Appalachian region, West Virginia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:29464-29474. [PMID: 32440881 DOI: 10.1007/s11356-020-09251-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Dissolved organic carbon (DOC) and iron (Fe) have been observed to be the important contributors to surface water brownification. Additionally, the DOC quality influences water color by forming Fe-DOC complexes that provide additive effects and is influenced by dominant land use type within watersheds. However, the influence of quantity and quality of DOC on Fe and water color is poorly understood in headwater streams. The aim of this study was to investigate the effects of DOC and Fe on water color in forest (FC) and pasture (GFC) fine-scale watersheds to remove the confounding effects of climate and soil parent material. Significant differences of DOC, Fe, and water absorbance at 420 nm (a420) between FC and GFC were found (p < 0.05). A dominant contribution to water color was from DOC (95.5 - 63.7%) with a decreasing trend when Fe increased from 0.011 to 0.258 mg L-1. There were no significant interactions between FC and GFC and Fe on either a420/DOC (p = 0.06) or specific ultraviolet absorbance at 254 nm (SUVA254) (p = 0.30). Increasing values of a420/DOC and SUVA254 were significantly associated with increasing Fe concentration (p < 0.01). Significant interactions were found between FC and GFC and Fe on spectral slope ratio (S ratio) (p < 0.01). The response rate of S ratio with increasing Fe per unit was 0.235 for GFC while it was - 11.043 for FC. These differences indicate that land use may change the quality of DOC, influence Fe-DOC interactions, and thus affect water color. Linking the effects of soil Fe and DOC and headwater Fe and DOC may help identify optimal management practice to mitigate surface water brownification.
Collapse
Affiliation(s)
- Lili Lei
- Division of Plant and Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, WV, 26505, USA
| | - James A Thompson
- Division of Plant and Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, WV, 26505, USA
| | - Louis M McDonald
- Division of Plant and Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, WV, 26505, USA.
| |
Collapse
|
10
|
Jokinen SA, Jilbert T, Tiihonen-Filppula R, Koho K. Terrestrial organic matter input drives sedimentary trace metal sequestration in a human-impacted boreal estuary. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 717:137047. [PMID: 32084679 DOI: 10.1016/j.scitotenv.2020.137047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
Coastal sediments play a fundamental role in processing anthropogenic trace metal inputs. Previous studies have shown that terrestrial organic matter (OM) is a significant vector for trace metal transport across the land-to-sea continuum, but little is known about the fate of land-derived metal-OM complexes in coastal sediments. Here, we use a comprehensive set of sediment pore water and solid-phase analyses to investigate how variations in terrestrial OM delivery since the 1950s have influenced trace metal accumulation and diagenesis in a human-impacted boreal estuary in the northern Baltic Sea. A key feature of our dataset is a strong correlation between terrestrial OM deposition and accumulation of metal-OM complexes in the sediments. Based on this strong coupling, we infer that the riverine input of terrestrial metal-OM complexes from the hinterland, followed by flocculation-induced settling in the estuary, effectively modulates sedimentary trace metal sequestration. While part of the trace metal pool associated with these complexes is efficiently recycled in the surface sediments during diagenesis, a substantial fraction is permanently buried as refractory metal-OM complexes or through incorporation into insoluble sulfides, thereby escaping further biological processing. These findings suggest that terrestrial OM input could play a more pivotal role in trace metal processing in coastal environments than hitherto acknowledged.
Collapse
Affiliation(s)
- Sami A Jokinen
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland; Lake and Marine Sediment Research Group, Department of Geography and Geology, University of Turku, FI-20014 Turku, Finland.
| | - Tom Jilbert
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland; Tvärminne Zoological Station, University of Helsinki, J.A. Palménintie 260, 10900 Hanko, Finland
| | - Rosa Tiihonen-Filppula
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
| | - Karoliina Koho
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
| |
Collapse
|
11
|
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.
Collapse
Affiliation(s)
| | | | - Anna‐Lena Axelsson
- Department of Forest Resource ManagementSwedish University of Agricultural SciencesUmeåSweden
| | | |
Collapse
|
12
|
Pschenyckyj CM, Clark JM, Shaw LJ, Griffiths RI, Evans CD. Effects of acidity on dissolved organic carbon in organic soil extracts, pore water and surface litters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:135585. [PMID: 31767326 DOI: 10.1016/j.scitotenv.2019.135585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/15/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
Over the past 30-40 years, dissolved organic carbon (DOC) concentrations have increased in soil solutions and surface waters in many acid-sensitive areas of Europe and North America. This has been linked to recovery from acidification in response to decreasing levels of atmospheric pollution. Evidence from radiocarbon dating suggests that DOC in surface waters is typically derived from recently photosynthesised organic matter such as plant litter and exudates, yet there is little information on the pH-sensitivity of organic matter solubility, or its decomposition, in litter layers and in different organic soils. Therefore the purpose of this study was to determine a) the sensitivity of DOC to acidity in different surface layers and soil types, in order to b) improve understanding of the key sources contributing to the increasing DOC trend. Such information is vital for understanding site specific characteristics contributing to inconsistencies in DOC release between catchments, and for improving predictions of carbon fluxes and budgets. Based on data collected at four established field pH-manipulation experiments in upland areas of the United Kingdom, we examined the sources, composition and acid-sensitivity of DOC export from the litter and organic soils. We found that litter generated nearly three times more DOC than the organic soils, consistent with radiocarbon evidence that recent plant inputs are a major source of DOC. Furthermore, litter derived DOC had lower specific ultraviolet light absorbance (SUVA) than organic soil DOC, suggesting greater biodegradability, and was not acid sensitive. In contrast, organic soil DOC concentrations were more strongly related to experimentally manipulated pH, implying that the mobility of this DOC may be subject to physicochemical rather than biotic controls. Our results suggest that physicochemically mediated controls on organic matter solubility may be a key driver behind the widely observed increases in surface water DOC in areas undergoing recovery from acidification.
Collapse
Affiliation(s)
- Catharine M Pschenyckyj
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, UK.
| | - Joanna M Clark
- Soil Research Centre, Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, The University of Reading, Whiteknights, PO Box 227, Reading RG6 6AB, UK
| | - Liz J Shaw
- Soil Research Centre, Department of Geography and Environmental Science, School of Archaeology, Geography and Environmental Science, The University of Reading, Whiteknights, PO Box 227, Reading RG6 6AB, UK
| | | | - Chris D Evans
- Centre for Ecology and Hydrology, Deiniol Rd, Bangor LL57 2UP, UK
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Parr TB, Inamdar SP, Miller MJ. Overlapping anthropogenic effects on hydrologic and seasonal trends in DOC in a surface water dependent water utility. WATER RESEARCH 2019; 148:407-415. [PMID: 30399555 DOI: 10.1016/j.watres.2018.10.065] [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: 06/26/2018] [Revised: 10/19/2018] [Accepted: 10/23/2018] [Indexed: 06/08/2023]
Abstract
Drinking water supplies are increasingly affected by overlapping anthropogenic global change processes. As a key currency of ecosystem function in aquatic ecosystems, dissolved organic carbon (DOC) concentration and composition is sensitive to many global change processes. However, DOC must also be removed to avoid the production of harmful disinfection byproducts as water is processed. Thus, understanding the effects of global change processes on the seasonal and long-term dynamics of DOC composition and concentration is critical for ensuring the sustainability of drinking water supplies. To understand these dynamics, we analyzed a novel 11-year time series of stream water DOC concentration and composition using Weighted Regressions on Time Discharge and Season (WRTDS) to understand the influences of co-occurring changes in climate and atmospheric deposition. We also discuss the implications for water supply provision and management. We found that, during our study period, overlapping global change processes in the watershed had the net effect of increasing the DOC aromaticity, as measured by SUVA254, at moderate to high discharge levels during the late spring and early summer and the autumn and early winter. However, changes in DOC concentration were more dynamic and we observed both increasing and decreasing trends depending on season and hydrologic state. During summer, at low to moderate flow levels we observed a significant (p < 0.05) increase in DOC concentration. During autumn, at moderate to high flow levels we observed a significant (p < 0.05) decrease in DOC concentration and an increase in SUVA254. For drinking water providers, our results suggest that close monitoring of source waters must be coupled with the development of plans accounting for season- and hydrology-specific long-term changes.
Collapse
Affiliation(s)
- Thomas B Parr
- University of Delaware, Department of Plant and Soil Science, Newark, DE, 19716, United States.
| | - Shreeram P Inamdar
- University of Delaware, Department of Plant and Soil Science, Newark, DE, 19716, United States
| | - Matthew J Miller
- City of Wilmington, Department of Public Works, Wilmington, DE, 19801, United States
| |
Collapse
|
16
|
Tesson SVM, Šantl-Temkiv T. Ice Nucleation Activity and Aeolian Dispersal Success in Airborne and Aquatic Microalgae. Front Microbiol 2018; 9:2681. [PMID: 30483227 PMCID: PMC6240693 DOI: 10.3389/fmicb.2018.02681] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 10/19/2018] [Indexed: 01/22/2023] Open
Abstract
Microalgae are common members of the atmospheric microbial assemblages. Diverse airborne microorganisms are known to produce ice nucleation active (INA) compounds, which catalyze cloud and rain formation, and thus alter cloud properties and their own deposition patterns. While the role of INA bacteria and fungi in atmospheric processes receives considerable attention, the numerical abundance and the capacity for ice nucleation in atmospheric microalgae are understudied. We isolated 81 strains of airborne microalgae from snow samples and determined their taxonomy by sequencing their ITS markers, 18S rRNA genes or 23S rRNA genes. We studied ice nucleation activity of airborne isolates, using droplet freezing assays, and their ability to withstand freezing. For comparison, we investigated 32 strains of microalgae from a culture collection, which were isolated from polar and temperate aqueous habitats. We show that ∼17% of airborne isolates, which belonged to taxa Trebouxiphyceae, Chlorophyceae and Stramenopiles, were INA. A large fraction of INA strains (over 40%) had ice nucleation activity at temperatures ≥-6°C. We found that 50% of aquatic microalgae were INA, but the majority were active at temperatures <-12°C. Most INA compounds produced by microalgae were proteinaceous and associated with the cells. While there were no deleterious effects of freezing on the viability of airborne microalgae, some of the aquatic strains were killed by freezing. In addition, the effect of desiccation was investigated for the aquatic strains and was found to constitute a limiting factor for their atmospheric dispersal. In conclusion, airborne microalgae possess adaptations to atmospheric dispersal, in contrast to microalgae isolated from aquatic habitats. We found that widespread taxa of both airborne and aquatic microalgae were INA at warm, sub-zero temperatures (>-15°C) and may thus participate in cloud and precipitation formation.
Collapse
Affiliation(s)
- Sylvie V. M. Tesson
- Aquatic Ecology, Department of Biology, Faculty of Science, Lund University, Lund, Sweden
| | - Tina Šantl-Temkiv
- Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
- Department of Physics and Astronomy, Stellar Astrophysics Centre, Aarhus University, Aarhus, Denmark
- Department of Bioscience, Arctic Research Centre, Aarhus University, Aarhus, Denmark
| |
Collapse
|
17
|
Marinos RE, Bernhardt ES. Soil carbon losses due to higher pH offset vegetation gains due to calcium enrichment in an acid mitigation experiment. Ecology 2018; 99:2363-2373. [DOI: 10.1002/ecy.2478] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 06/15/2018] [Accepted: 07/13/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Richard E. Marinos
- Nicholas School of the Environment Duke University Durham North Carolina 27708 USA
| | | |
Collapse
|
18
|
Creed IF, Bergström AK, Trick CG, Grimm NB, Hessen DO, Karlsson J, Kidd KA, Kritzberg E, McKnight DM, Freeman EC, Senar OE, Andersson A, Ask J, Berggren M, Cherif M, Giesler R, Hotchkiss ER, Kortelainen P, Palta MM, Vrede T, Weyhenmeyer GA. Global change-driven effects on dissolved organic matter composition: Implications for food webs of northern lakes. GLOBAL CHANGE BIOLOGY 2018; 24:3692-3714. [PMID: 29543363 DOI: 10.1111/gcb.14129] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/05/2018] [Indexed: 05/21/2023]
Abstract
Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial-aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)-the messenger between terrestrial and lake ecosystems-with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change-driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice-out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans.
Collapse
Affiliation(s)
- Irena F Creed
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada
| | | | - Charles G Trick
- Interfaculty Program on Public Health & Department of Biology, Western University, London, ON, Canada
| | - Nancy B Grimm
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Dag O Hessen
- Section for Aquatic Biology and Toxicology, University of Oslo, Oslo, Norway
| | - Jan Karlsson
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Karen A Kidd
- Department of Biology and Canadian Rivers Institute, University of New Brunswick, Saint John, NB, Canada
| | | | | | - Erika C Freeman
- Department of Geography, Western University, London, ON, Canada
| | - Oscar E Senar
- Department of Geography, Western University, London, ON, Canada
| | - Agneta Andersson
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Jenny Ask
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Martin Berggren
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Mehdi Cherif
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Reiner Giesler
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Erin R Hotchkiss
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | | | - Monica M Palta
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Tobias Vrede
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gesa A Weyhenmeyer
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
| |
Collapse
|
19
|
Oulehle F, Tahovská K, Chuman T, Evans CD, Hruška J, Růžek M, Bárta J. Comparison of the impacts of acid and nitrogen additions on carbon fluxes in European conifer and broadleaf forests. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 238:884-893. [PMID: 29631233 DOI: 10.1016/j.envpol.2018.03.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
Increased reactive nitrogen (N) loadings to terrestrial ecosystems are believed to have positive effects on ecosystem carbon (C) sequestration. Global "hot spots" of N deposition are often associated with currently or formerly high deposition of sulphur (S); C fluxes in these regions might therefore not be responding solely to N loading, and could be undergoing transient change as S inputs change. In a four-year, two-forest stand (mature Norway spruce and European beech) replicated field experiment involving acidity manipulation (sulphuric acid addition), N addition (NH4NO3) and combined treatments, we tested the extent to which altered soil solution acidity or/and soil N availability affected the concentration of soil dissolved organic carbon (DOC), soil respiration (Rs), microbial community characteristics (respiration, biomass, fungi and bacteria abundances) and enzyme activity. We demonstrated a large and consistent suppression of soil water DOC concentration driven by chemical changes associated with increased hydrogen ion concentrations under acid treatments, independent of forest type. Soil respiration was suppressed by sulphuric acid addition in the spruce forest, accompanied by reduced microbial biomass, increased fungal:bacterial ratios and increased C to N enzyme ratios. We did not observe equivalent effects of sulphuric acid treatments on Rs in the beech forest, where microbial activity appeared to be more tightly linked to N acquisition. The only changes in C cycling following N addition were increased C to N enzyme ratios, with no impact on C fluxes (either Rs or DOC). We conclude that C accumulation previously attributed solely to N deposition could be partly attributable to their simultaneous acidification.
Collapse
Affiliation(s)
- Filip Oulehle
- Czech Geological Survey, Klárov 3, 118 21 Prague, Czech Republic; Global Change Research Institute, AS CR, Bělidla 986/4a, 60300 Brno, Czech Republic.
| | - Karolina Tahovská
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - Tomáš Chuman
- Czech Geological Survey, Klárov 3, 118 21 Prague, Czech Republic; Department of Physical Geography, Faculty of Science, Charles University, Albertov 6, 128 43 Prague, Czech Republic
| | - Chris D Evans
- Centre for Ecology and Hydrology, Environmental Centre Wales, Deiniol Road, Bangor, LL57 2UW, UK
| | - Jakub Hruška
- Czech Geological Survey, Klárov 3, 118 21 Prague, Czech Republic; Global Change Research Institute, AS CR, Bělidla 986/4a, 60300 Brno, Czech Republic
| | - Michal Růžek
- Czech Geological Survey, Klárov 3, 118 21 Prague, Czech Republic; Department of Physical Geography, Faculty of Science, Charles University, Albertov 6, 128 43 Prague, Czech Republic
| | - Jiří Bárta
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
| |
Collapse
|
20
|
SanClements MD, Fernandez IJ, Lee RH, Roberti JA, Adams MB, Rue GA, McKnight DM. Long-Term Experimental Acidification Drives Watershed Scale Shift in Dissolved Organic Matter Composition and Flux. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2649-2657. [PMID: 29430920 DOI: 10.1021/acs.est.7b04499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Over the last several decades dissolved organic carbon concentrations (DOC) in surface waters have increased throughout much of the northern hemisphere. Several hypotheses have been proposed regarding the drivers of this phenomenon including decreased sulfur (S) deposition working via an acidity- change mechanism. Using fluorescence spectroscopy and data from two long-term (24+ years at completion of this study) whole watershed acidification experiments, that is, the Bear Brook Watershed in Maine (BBWM) and Fernow Experimental Forest in West Virginia (FEF) allowed us to control for factors other than the acidity-change mechanism (e.g., differing vegetation, shifting climate), resulting in the first study we are aware of where the acidity change mechanism could be experimentally isolated at the whole ecosystem and decadal scales as the driver of shifts in DOM dynamics. The multidecadal record of stream chemistry at BBWM demonstrates a significantly lower DOC concentration in the treated compared to the reference watershed. Additionally, at both BBWM and FEF we found significant and sustained differences in stream fluorescence index (FI) between the treated and reference watersheds, with the reference watersheds demonstrating a stronger terrestrial DOM signature. These data, coupled with evidence of pH shifts in upper soil horizons support the hypotheses that declines in S deposition are driving changes in the solubility of soil organic matter and increased flux of terrestrial DOC to water bodies.
Collapse
Affiliation(s)
- Michael D SanClements
- Institute of Arctic and Alpine Research , University of Colorado Boulder , Boulder , Colorado 80303 , United States
- National Ecological Observatory Network , Boulder , Colorado 80301 , United States
| | - Ivan J Fernandez
- School of Forest Resources and Climate Change Institute , University of Maine , Orono , Maine 04469 , United States
| | - Robert H Lee
- National Ecological Observatory Network , Boulder , Colorado 80301 , United States
| | - Joshua A Roberti
- National Ecological Observatory Network , Boulder , Colorado 80301 , United States
| | - Mary Beth Adams
- USDA Forest Service, Northern Research Station , Morgantown , West Virginia 26505 , United States
| | - Garret A Rue
- Institute of Arctic and Alpine Research , University of Colorado Boulder , Boulder , Colorado 80303 , United States
| | - Diane M McKnight
- Institute of Arctic and Alpine Research , University of Colorado Boulder , Boulder , Colorado 80303 , United States
| |
Collapse
|
21
|
Sand-Jensen K, Bruun HH, Nielsen TF, Christiansen DM, Hartvig P, Schou JC, Baastrup-Spohr L. The Dangers of Being a Small, Oligotrophic and Light Demanding Freshwater Plant across a Spatial and Historical Eutrophication Gradient in Southern Scandinavia. FRONTIERS IN PLANT SCIENCE 2018; 9:66. [PMID: 29456545 PMCID: PMC5801560 DOI: 10.3389/fpls.2018.00066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/12/2018] [Indexed: 06/01/2023]
Abstract
European freshwater habitats have experienced a severe loss of plant diversity, regionally and locally, over the last century or more. One important and well-established driver of change is eutrophication, which has increased with rising population density and agricultural intensification. However, reduced disturbance of lake margins may have played an additional key role. The geographical variation in water chemistry, which has set the scene for - and interacted with - anthropogenic impact, is much less well understood. We took advantage of some recently completed regional plant distribution surveys, relying on hundreds of skilled citizen scientists, and analyzed the hydrophyte richness to environment relations in five contiguous South-Scandinavian regions. For three of the regions, we also assessed changes to the freshwater flora over the latest 50-80 years. We found a considerable variation in background total phosphorus concentrations and alkalinity, both within and between regions. The prevalence of functional groups differed between regions in accordance with the environmental conditions and the species' tolerance to turbid waters. Similarly, the historical changes within regions followed the same trend in correspondence to the altered environmental conditions over time. Small submerged species decreased relative to tall submerged and floating-leaved species along the regional and historical eutrophication gradients. These changes were accompanied by systematically greater relative abundance of species of higher phosphorus prevalence. We conclude that species traits in close correspondence with anthropogenic impacts are the main determinants of local, regional and historical changes of species distribution and occupancy, while pure biogeography plays a minor role. Conservation measures, such as re-oligotrophication and re-established disturbance regimes through grazing and water level fluctuations, may help reduce the tall reed vegetation, restore the former richness of the freshwater flora and safeguard red-listed species, although extended time delays are anticipated in nutrient-rich regions, in which species only survive at minute abundance in isolated refugia.
Collapse
Affiliation(s)
- Kaj Sand-Jensen
- Freshwater Biological Section, Department of Biology, Faculty of Natural and Life Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Henrik Bruun
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Tora Finderup Nielsen
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ditte M. Christiansen
- Freshwater Biological Section, Department of Biology, Faculty of Natural and Life Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Per Hartvig
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | | | - Lars Baastrup-Spohr
- Freshwater Biological Section, Department of Biology, Faculty of Natural and Life Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
22
|
Jiang T, Kaal J, Liang J, Zhang Y, Wei S, Wang D, Green NW. Composition of dissolved organic matter (DOM) from periodically submerged soils in the Three Gorges Reservoir areas as determined by elemental and optical analysis, infrared spectroscopy, pyrolysis-GC-MS and thermally assisted hydrolysis and methylation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017. [PMID: 28641186 DOI: 10.1016/j.scitotenv.2017.06.114] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Soil-derived dissolved organic matter (DOM) has a major influence in biogeochemical processes related to contaminant dynamics and greenhouse gas emissions, due to its reactivity and its bridging role between the soil and aquatic systems. Within the Three Gorges Reservoir (TGR, China) area, an extensive water-fluctuation zone periodically submerges the surrounding soils. Here we report a characterization study of soil-derived DOM across the TGR areas, using elemental and optical analysis, infrared spectroscopy (FTIR), pyrolysis-GC-MS (Py-GC-MS) and thermally assisted hydrolysis and methylation (THM-GC-MS). The results showed that the soil DOM from the TGR area is a mixture of "allochthonous" (i.e., plant-derived/terrigenous) and "autochthonous" (i.e., microbial) origins. The terrigenous DOM is composed primarily of phenolic and aliphatic structures from lignin and aliphatic biopolymers (i.e. cutin, suberin), respectively. Multivariate statistics differentiated between two fractions of the microbial DOM, i.e. chitin-derived, perhaps from fungi and arthropods in soil, and protein-derived, partially sourced from algal or aquatic organisms. Molecular proxies of source and degradation state were in good agreement with optical parameters such as SUVA254, the fluorescence index (FI) and the humification index (HIX). The combined use of elemental analysis, fluorescence spectroscopy, and Py-GC-MS provides rigorous and detailed DOM characterization, whereas THM-GC-MS is useful for more precise but qualitative identification of the different phenolic (cinnamyl, p-hydroxyphenyl, guaiacyl, syringyl and tannin-derived) and aliphatic materials. With the multi-methodological approach used in this study, FTIR was the least informative, in part, because of the interference of inorganic matter in the soil DOM samples. The soil DOM from the TGR's water fluctuation zone exhibited considerable compositional diversity, mainly related to the balance between DOM source (microbial- or plant-derived), local vegetation and anthropogenic activities (e.g., agriculture). Finally, the relationship between DOM composition and its potential reactivity with substances of environmental concerns in the TGR area are also discussed.
Collapse
Affiliation(s)
- Tao Jiang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden.
| | - Joeri Kaal
- Ciencia do Sistema Terra, Departamento de Edafoloxía e Química Agrícola, Universidade de Santiago de Compostela, Campus Sur s/n, Santiago de Compostela 15782, Spain; Instituto de Ciencias del Patrimonio (Incipit), Consejo Superior de Investigaciones Científicas (CSIC), Avda. de Vigo sn, 15705 Santiago de Compostela, Spain
| | - Jian Liang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Yaoling Zhang
- Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
| | - Shiqiang Wei
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Dingyong Wang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Nelson W Green
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States
| |
Collapse
|
23
|
Davies GM, Kettridge N, Stoof CR, Gray A, Ascoli D, Fernandes PM, Marrs R, Allen KA, Doerr SH, Clay GD, McMorrow J, Vandvik V. The role of fire in UK peatland and moorland management: the need for informed, unbiased debate. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0342. [PMID: 27216512 PMCID: PMC4874417 DOI: 10.1098/rstb.2015.0342] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2016] [Indexed: 11/16/2022] Open
Abstract
Fire has been used for centuries to generate and manage some of the UK's cultural landscapes. Despite its complex role in the ecology of UK peatlands and moorlands, there has been a trend of simplifying the narrative around burning to present it as an only ecologically damaging practice. That fire modifies peatland characteristics at a range of scales is clearly understood. Whether these changes are perceived as positive or negative depends upon how trade-offs are made between ecosystem services and the spatial and temporal scales of concern. Here we explore the complex interactions and trade-offs in peatland fire management, evaluating the benefits and costs of managed fire as they are currently understood. We highlight the need for (i) distinguishing between the impacts of fires occurring with differing severity and frequency, and (ii) improved characterization of ecosystem health that incorporates the response and recovery of peatlands to fire. We also explore how recent research has been contextualized within both scientific publications and the wider media and how this can influence non-specialist perceptions. We emphasize the need for an informed, unbiased debate on fire as an ecological management tool that is separated from other aspects of moorland management and from political and economic opinions. This article is part of the themed issue ‘The interaction of fire and mankind’.
Collapse
Affiliation(s)
- G Matt Davies
- School of Environment and Natural Resources, The Ohio State University, Kottman Hall, 2021 Coffey Road, Columbus, OH 43210, USA
| | - Nicholas Kettridge
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B31 2DX, UK
| | - Cathelijne R Stoof
- Soil Geography and Landscape Group, Wageningen University, PO Box 47, Wageningen 6700 AA, The Netherlands
| | - Alan Gray
- NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, Edinburgh EH26 0QB, UK
| | - Davide Ascoli
- Department of Agricultural, Forest and Food Sciences, University of Torino, Largo Paolo Braccini 2, Grugliasco (TO) 10095, Italy
| | - Paulo M Fernandes
- Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas, Universidade de Tras-os-Montes e Alto Douro, Vila Real, Portugal
| | - Rob Marrs
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Katherine A Allen
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Stefan H Doerr
- Department of Geography, Swansea University, Swansea, UK
| | - Gareth D Clay
- School of Environment, Education and Development, The University of Manchester, Manchester M13 9PL, UK
| | - Julia McMorrow
- School of Environment, Education and Development, The University of Manchester, Manchester M13 9PL, UK
| | - Vigdis Vandvik
- Department of Biology, University of Bergen, Postboks 7803, Bergen 5020, Norway
| |
Collapse
|
24
|
Sawicka K, Rowe EC, Evans CD, Monteith DT, Wade AJ. Modelling impacts of atmospheric deposition and temperature on long-term DOC trends. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 578:323-336. [PMID: 27838058 DOI: 10.1016/j.scitotenv.2016.10.164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/20/2016] [Accepted: 10/20/2016] [Indexed: 06/06/2023]
Abstract
It is increasingly recognised that widespread and substantial increases in Dissolved organic carbon (DOC) concentrations in remote surface, and soil, waters in recent decades are linked to declining acid deposition. Effects of rising pH and declining ionic strength on DOC solubility have been proposed as potential dominant mechanisms. However, since DOC in these systems is derived mainly from recently-fixed carbon, and since organic matter decomposition rates are considered sensitive to temperature, uncertainty persists over the extent to which other drivers that could influence DOC production. Such potential drivers include fertilisation by nitrogen (N) and global warming. We therefore ran the dynamic soil chemistry model MADOC for a range of UK soils, for which time series data are available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on soil DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to raise the "acid recovery DOC baseline" significantly. In contrast, reductions in non-marine chloride deposition and effects of long term warming appeared to have been relatively unimportant. The suggestion that future DOC concentrations might exceed preindustrial levels as a consequence of nitrogen pollution has important implications for drinking water catchment management and the setting and pursuit of appropriate restoration targets, but findings still require validation from reliable centennial-scale proxy records, such as those being developed using palaeolimnological techniques.
Collapse
Affiliation(s)
- K Sawicka
- Soil Research Centre, Department of Geography and Environmental Science, University of Reading, Reading RG6 6DW, UK; Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor LL57 2UW, UK.
| | - E C Rowe
- Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor LL57 2UW, UK
| | - C D Evans
- Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor LL57 2UW, UK
| | - D T Monteith
- Environmental Change Network, Centre for Ecology and Hydrology, Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP, UK
| | - A J Wade
- Soil Research Centre, Department of Geography and Environmental Science, University of Reading, Reading RG6 6DW, UK
| |
Collapse
|
25
|
Rasconi S, Gall A, Winter K, Kainz MJ. Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton. PLoS One 2015; 10:e0140449. [PMID: 26461029 PMCID: PMC4603799 DOI: 10.1371/journal.pone.0140449] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 09/25/2015] [Indexed: 11/24/2022] Open
Abstract
Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor (“brownification”) of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C) and brownification will, a) cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b) extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification) caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans), and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development).
Collapse
Affiliation(s)
- Serena Rasconi
- WasserCluster–Biological Station Lunz, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria
- * E-mail:
| | - Andrea Gall
- WasserCluster–Biological Station Lunz, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria
| | - Katharina Winter
- WasserCluster–Biological Station Lunz, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria
| | - Martin J. Kainz
- WasserCluster–Biological Station Lunz, Inter-university Centre for Aquatic Ecosystem Research, A-3293 Lunz am See, Austria
| |
Collapse
|
26
|
Kaňa J, Tahovská K, Kopáček J, Šantrůčková H. Excess of Organic Carbon in Mountain Spruce Forest Soils after Bark Beetle Outbreak Altered Microbial N Transformations and Mitigated N-Saturation. PLoS One 2015; 10:e0134165. [PMID: 26230678 PMCID: PMC4521819 DOI: 10.1371/journal.pone.0134165] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/06/2015] [Indexed: 11/19/2022] Open
Abstract
Mountain forests in National park Bohemian Forest (Czech Republic) were affected by bark beetle attack and windthrows in 2004-2008, followed by an extensive tree dieback. We evaluated changes in the biochemistry of the uppermost soil horizons with the emphasis on carbon (C) and nitrogen (N) cycling in a near-natural spruce (Picea abies) mountain forest after the forest dieback, and compared it with an undisturbed control plot of similar age, climate, elevation, deposition, N-saturation level, and land use history. We hypothesised that the high litter input after forest dieback at the disturbed plot and its consequent decomposition might influence the availability of C for microorganisms, and consequently, N transformations in the soil. The concentrations of dissolved organic C (DOC) and N (DON) in soil water extracts rapidly increased at the disturbed plot for 3 yeas and then continually decreased. Net ammonification exhibited a similar trend as DOC and DON, indicating elevated mineralization. Despite the high ammonium concentrations found after the forest dieback (an increase from 0.5 mmol kg-1 to 2-3 mmol kg-1), net nitrification was stable and low during these 3 years. After the DOC depletion and decrease in microbial biomass 5 years after the forest dieback, net nitrification started to rise, and nitrate concentrations increased from 0.2-1 mmol kg-1 to 2-3 mmol kg-1. Our results emphasize the key role of the availability of organic C in microbial N transformations, which probably promoted microbial heterotrophic activity at the expense of slow-growing nitrifiers.
Collapse
Affiliation(s)
- Jiří Kaňa
- Institute of Hydrobiology, Biology Centre of the CAS, v.v.i., České Budějovice, Czech Republic
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
- * E-mail:
| | - Karolina Tahovská
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| | - Jiří Kopáček
- Institute of Hydrobiology, Biology Centre of the CAS, v.v.i., České Budějovice, Czech Republic
| | - Hana Šantrůčková
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| |
Collapse
|
27
|
Peacock M, Freeman C, Gauci V, Lebron I, Evans CD. Investigations of freezing and cold storage for the analysis of peatland dissolved organic carbon (DOC) and absorbance properties. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2015; 17:1290-1301. [PMID: 26051006 DOI: 10.1039/c5em00126a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Although measured rates of biological degradation of DOC are typically low under dark conditions, it is assumed that water samples must be analysed soon after collection to provide an accurate measure of DOC concentration and UV-visible absorbance. To examine the impact of storage on DOC quality and quantity, we took water samples from an ombrotrophic peatland, and stored them in the dark at 4 °C for 138-1082 days. A median of 29% of DOC was lost during storage, but losses of absorbance at 254 nm were less. DOC loss followed a first-order exponential decay function, and was dependent on storage time. DOC half-life was calculated as 1253 days. Specific absorbance at 254 nm suggested that samples containing more aromatic DOC were more resistant to degradation, although time functioned as the primary control. Samples from two fens showed that loss of absorbance was greater at 400 nm rather than 254 nm, after 192 days storage, suggesting that non-aromatic DOC is preferentially degraded. These results suggest that samples can be stored for several months before losses of DOC become detectable, and that it is possible to back-calculate initial DOC concentrations in long-term stored samples based on known decay rates. Freeze/thaw experiments using samples from a range of peatlands suggested that DOC concentration was mostly unaffected by the process, but DOC increased 37% in one sample. Freezing had unpredictable and sometimes strong effects on absorbance, SUVA and E ratios, therefore freezing is not recommended as a method of preservation for these analyses.
Collapse
Affiliation(s)
- Mike Peacock
- Department of Environment Earth and Ecosystems, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.
| | | | | | | | | |
Collapse
|
28
|
Early land use and centennial scale changes in lake-water organic carbon prior to contemporary monitoring. Proc Natl Acad Sci U S A 2015; 112:6579-84. [PMID: 25964363 DOI: 10.1073/pnas.1501505112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Organic carbon concentrations have increased in surface waters across parts of Europe and North America during the past decades, but the main drivers causing this phenomenon are still debated. A lack of observations beyond the last few decades inhibits a better mechanistic understanding of this process and thus a reliable prediction of future changes. Here we present past lake-water organic carbon trends inferred from sediment records across central Sweden that allow us to assess the observed increase on a centennial to millennial time scale. Our data show the recent increase in lake-water carbon but also that this increase was preceded by a landscape-wide, long-term decrease beginning already A.D. 1450-1600. Geochemical and biological proxies reveal that these dynamics coincided with an intensification of human catchment disturbance that decreased over the past century. Catchment disturbance was driven by the expansion and later cessation of widespread summer forest grazing and farming across central Scandinavia. Our findings demonstrate that early land use strongly affected past organic carbon dynamics and suggest that the influence of historical landscape utilization on contemporary changes in lake-water carbon levels has thus far been underestimated. We propose that past changes in land use are also a strong contributing factor in ongoing organic carbon trends in other regions that underwent similar comprehensive changes due to early cultivation and grazing over centuries to millennia.
Collapse
|
29
|
Jimenez-Sanchez C, Wick LY, Cantos M, Ortega-Calvo JJ. Impact of dissolved organic matter on bacterial tactic motility, attachment, and transport. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4498-505. [PMID: 25734420 DOI: 10.1021/es5056484] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Bacterial dispersal is a key driver of the ecology of microbial contaminant degradation in soils. This work investigated the role of dissolved organic matter (DOM) in the motility, attachment, and transport of the soil bacterium Pseudomonas putida G7 in saturated porous media. The study is based on the hypothesis that DOM quality is critical to triggering tactic motility and, consequently, affects bacterial transport and dispersal. Sunflower root exudates, humic acids (HA), and the synthetic oleophilic fertilizer S-200 were used as representatives of fresh, weathered, and artificially processed DOM with high nitrogen and phosphorus contents, respectively. We studied DOM levels of 16-130 mg L(-1), which are representative of DOM concentrations typically found in agricultural soil pore water. In contrast to its responses to HA and S-200, strain G7 exhibited a tactic behavior toward root exudates, as quantified by chemotaxis assays and single-cell motility observations. All DOM types promoted bacterial transport through sand at high concentrations (∼ 130 mg L(-1)). At low DOM concentrations (∼ 16 mg L(-1)), the enhancement occurred only in the presence of sunflower root exudates, and this enhancement did not occur with G7 bacteria devoid of flagella. Our results suggest that tactic DOM effectors strongly influence bacterial transport and the interception probability of motile bacteria by collector surfaces.
Collapse
Affiliation(s)
- Celia Jimenez-Sanchez
- †Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Apartado 1052, E-41080-Seville, Spain
| | - Lukas Y Wick
- ‡Helmholtz Centre for Environmental Research - UFZ, Permosertraße 15, D-04318 Leipzig, Germany
| | - Manuel Cantos
- †Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Apartado 1052, E-41080-Seville, Spain
| | - José-Julio Ortega-Calvo
- †Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Apartado 1052, E-41080-Seville, Spain
| |
Collapse
|
30
|
Valinia S, Futter MN, Cosby BJ, Rosén P, Fölster J. Simple models to estimate historical and recent changes of total organic carbon concentrations in lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:386-94. [PMID: 25485992 DOI: 10.1021/es503170r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Quantifying human impacts on the natural environment requires credible reconstructions of reference conditions. Anthropogenic acidification of surface waters is strongly influenced by total organic carbon (TOC) concentrations. Because both the degree of acidification and recovery are dependent on historical TOC concentrations, simple models to estimate changes in surface water TOC between reference conditions (1860) and the present day (2012) are needed. We used visible near infrared spectroscopy (VNIRS) of lake sediments to reconstruct reference condition TOC and long-term monitoring data to predict recent changes. Two empirical models were developed to predict: (i) historical TOC trends between reference conditions (1860) and peak acidification (1980) and (ii) trends in TOC between 1988 and 2012. The models were statistically robust with adj. R(2) of (i) 0.85 and (ii) 0.71, respectively. Models were driven by lake and catchment area, wetlands, historical sulfur deposition and water chemistry. Present day TOC concentrations are similar to VNIRS-reconstructed and modeled reference condition TOC in Swedish lakes. The results are valuable for understanding drivers of TOC changes in lakes and for more credible assessments of reference conditions needed for water management in Europe and elsewhere.
Collapse
Affiliation(s)
- Salar Valinia
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences , Lennart Hjelms väg 9, SE-75007 Uppsala, Sweden
| | | | | | | | | |
Collapse
|
31
|
Peacock M, Evans CD, Fenner N, Freeman C, Gough R, Jones TG, Lebron I. UV-visible absorbance spectroscopy as a proxy for peatland dissolved organic carbon (DOC) quantity and quality: considerations on wavelength and absorbance degradation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:1445-61. [PMID: 24728590 DOI: 10.1039/c4em00108g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Absorbance in the UV or visible spectrum (UV-vis) is commonly used as a proxy for DOC concentrations in waters draining upland catchments. To determine the appropriateness of different UV-vis measurements we used surface and pore water samples from two Welsh peatlands in four different experiments: (i) an assessment of single wavelength proxies (1 nm increments between 230-800 nm) for DOC concentration demonstrated that 254 nm was more accurate than 400 nm. The highest R(2) values between absorbance and DOC concentration were generated using 263 nm for one sample set (R(2) = 0.91), and 230 nm for the other three sample sets (respective R(2) values of 0.86, 0.81, and 0.93). (ii) A comparison of different DOC concentration proxies, including single wavelength proxies, a two wavelength model, a proxy using phenolic concentration, and a proxy using the area under a UV spectrum at 250-350 nm. It was found that both a single wavelength proxy (≤263 nm) and a two wavelength model performed well for both pore water and surface water. (iii) An evaluation of the E2 : E3, E2 : E4, E4 : E6 ratios, and SUVA (absorbance at 254 nm normalised to DOC concentration) as indicators of DOC quality showed that the E4 : E6 ratio was subject to extensive variation over time, and was highly correlated between surface water and pore water, suggesting that it is a useful metric to determine temporal changes in DOC quality. (iv) A repeated weekly analysis over twelve weeks showed no consistent change in UV-vis absorbance, and therefore an inferred lack of degradation of total DOC in samples that were filtered and stored in the dark at 4 °C.
Collapse
Affiliation(s)
- Mike Peacock
- Wolfson Carbon Capture Laboratory, School of Biological Sciences, Bangor University, Deiniol Road, LL57 2UW, UK.
| | | | | | | | | | | | | |
Collapse
|
32
|
Riedel T, Biester H, Dittmar T. Molecular fractionation of dissolved organic matter with metal salts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:4419-4426. [PMID: 22414136 DOI: 10.1021/es203901u] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Coagulation of dissolved organic matter (DOM) by hydrolyzing metals is an important environmental process with particular relevance, e.g., for the cycling of organic matter in metal-rich aquatic systems or the flocculation of organic matter in wastewater treatment plants. Often, a nonremovable fraction of DOM remains in solution even at low DOM/metal ratios. Because coagulation by metals results from interactions with functional groups, we hypothesize that noncoagulating fractions have a distinct molecular composition. To test the hypothesis, we analyzed peat-derived dissolved organic matter remaining in solution after mixing with salts of Ca, Al, and Fe using 15 T Electrospray Ionization Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR-MS). Addition of metals resulted in a net removal of DOM. Also a reduction of molecular diversity was observed, as the number of peaks from the ESI-FT-ICR-MS spectra decreased. At DOM/metal ratios of ∼9 Ca did not show any preference for distinct molecular fractions, while Fe and Al removed preferentially the most oxidized compounds (O/C ratio >0.4) of the peat leachate. Lowering DOM/metal ratios to ∼1 resulted in further removal of less oxidized as well as more aromatic compounds ("black carbon"). Molecular composition in the residual solution after coagulation was more saturated, less polar, and less oxidized compared to the original peat leachate and exhibited a surprising similarity with DOM of marine origin. By identifying more than 9200 molecular formulas we can show that structural properties (saturation and aromaticity) and oxygen content of individual DOM molecules play an important role in coagulation with metals. We conclude that polyvalent cations not only alter the net mobility but also the very molecular composition of DOM in aquatic environments.
Collapse
Affiliation(s)
- Thomas Riedel
- Institut für Geoökologie, Technische Universität Braunschweig, 38106 Braunschweig, Deutschland.
| | | | | |
Collapse
|
33
|
SanClements MD, Oelsner GP, McKnight DM, Stoddard JL, Nelson SJ. New insights into the source of decadal increases of dissolved organic matter in acid-sensitive lakes of the northeastern United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3212-9. [PMID: 22369674 DOI: 10.1021/es204321x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The last several decades have seen decreases in SO(4)(2-) deposition across the northeastern United States. As a result, SO(4)(2-) concentrations in lakes and streams have also decreased and many surface water bodies have become less acidic. During the same time period, there has been a concurrent increase in dissolved organic carbon (DOC) concentrations in many lakes and streams. We used fluorescence spectroscopy to characterize the dissolved organic matter (DOM) quality of archived samples from nine acid-sensitive lakes in Maine collected between 1993 and 2009, and determined that increased DOM contributions to lakes were primarily derived from litter and soil. All five lakes with increasing DOC trends demonstrated significant decreasing (i.e., more terrestrial) trends in fluorescence index (FI) and significant positive correlations between SO(4)(2-) and FI. This study used the chemical signature of terrestrial DOM to support the hypothesis that increased DOC concentrations in lakes and streams are driven by declining acid deposition and increased solubility of soil organic matter across a large area of the landscape.
Collapse
Affiliation(s)
- Michael D SanClements
- Institute of Arctic and Alpine Research, University of Colorado Boulder, 1560 30th Street, Boulder, Colorado 80304, United States.
| | | | | | | | | |
Collapse
|