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Davis MJ, Woo I, De La Cruz SEW, Ellings CS, Hodgson S, Nakai G. Allochthonous marsh subsidies enhances food web productivity in an estuary and its surrounding ecosystem mosaic. PLoS One 2024; 19:e0296836. [PMID: 38421974 PMCID: PMC10903911 DOI: 10.1371/journal.pone.0296836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 12/20/2023] [Indexed: 03/02/2024] Open
Abstract
Terrestrial organic matter is believed to play an important role in promoting resilient estuarine food webs, but the inherent interconnectivity of estuarine systems often obscures the origins and importance of these terrestrial inputs. To determine the relative contributions of terrestrial (allochthonous) and aquatic (autochthonous) organic matter to the estuarine food web, we analyzed carbon, nitrogen, and sulfur stable isotopes from multiple trophic levels, environmental strata, and habitats throughout the estuarine habitat mosaic. We used a Bayesian stable isotope mixing model (SIMM) to parse out relationships among primary producers, invertebrates, and a pelagic and demersal fish species (juvenile Chinook salmon and sculpin, respectively). The study was carried out in the Nisqually River Delta (NRD), Washington, USA, a recently-restored, macrotidal estuary with a diverse habitat mosaic. Plant groupings of macroalgae, eelgrass, and tidal marsh plants served as the primary base components of the NRD food web. About 90% of demersal sculpin diets were comprised of benthic and pelagic crustaceans that were fed by autochthonous organic matter contributions from aquatic vegetation. Juvenile salmon, on the other hand, derived their energy from a mix of terrestrial, pelagic, and benthic prey, including insects, dipterans, and crustaceans. Consequently, allochthonous terrestrial contributions of organic matter were much greater for salmon, ranging between 26 and 43%. These findings demonstrate how connectivity among estuarine habitat types and environmental strata facilitates organic matter subsidies. This suggests that management actions that improve or restore lateral habitat connectivity as well as terrestrial-aquatic linkages may enhance allochthonous subsidies, promoting increased prey resources and ecosystem benefits in estuaries.
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Affiliation(s)
- Melanie J. Davis
- U.S. Geological Survey, Western Ecological Research Center, Olympia Substation, Olympia, Washington, United States of America
| | - Isa Woo
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, Moffett Field, California, United States of America
| | - Susan E. W. De La Cruz
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, Moffett Field, California, United States of America
| | - Christopher S. Ellings
- Nisqually Indian Tribe, Department of Natural Resources, Olympia, Washington, United States of America
| | - Sayre Hodgson
- Nisqually Indian Tribe, Department of Natural Resources, Olympia, Washington, United States of America
| | - Glynnis Nakai
- U.S. Fish and Wildlife Service, Billy Frank Jr. Nisqually National Wildlife Refuge, Olympia, Washington, United States of America
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2
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Carrasco N, McGovern M, Evenset A, Søreide JE, Arts MT, Jonsson S, Poste AE. Seasonal riverine inputs may affect diet and mercury bioaccumulation in Arctic coastal zooplankton. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167643. [PMID: 37806586 DOI: 10.1016/j.scitotenv.2023.167643] [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: 07/26/2023] [Revised: 09/17/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
Climate change driven increases in permafrost thaw and terrestrial runoff are expected to facilitate the mobilization and transport of mercury (Hg) from catchment soils to coastal areas in the Arctic, potentially increasing Hg exposure of marine food webs. The main aim of this study was to determine the impacts of seasonal riverine inputs on land-ocean Hg transport, zooplankton diet and Hg bioaccumulation in an Arctic estuary (Adventfjorden, Svalbard). The Adventelva River was a source of dissolved and particulate Hg to Adventfjorden, especially in June and July during the river's main discharge period. Stable isotope and fatty acid analyses suggest that zooplankton diet varied seasonally with diatoms dominating during the spring phytoplankton bloom in May and with increasing contributions of dinoflagellates in the summer months. In addition, there was evidence of increased terrestrial carbon utilization by zooplankton in June and July, when terrestrial particles contributed substantially to the particulate organic matter pool. Total (TotHg) and methyl Hg (MeHg) concentrations in zooplankton increased from April to August related to increased exposure to riverine inputs, and to shifts in zooplankton diet and community structure. Longer and warmer summer seasons will probably increase riverine runoff and thus Hg exposure to Arctic zooplankton.
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Affiliation(s)
- Nathalie Carrasco
- Department of Arctic Marine Biology, UiT, The Arctic University of Norway, 9019 Tromsø, Norway; Oceanographic Institute - Prince Albert I Foundation, 98000, Monaco; Norwegian Institute for Water Research, 9007 Tromsø, Norway.
| | - Maeve McGovern
- Norwegian Institute for Water Research, 9007 Tromsø, Norway
| | | | | | - Michael T Arts
- Toronto Metropolitan University, Toronto M5B 2K3, Canada
| | - Sofi Jonsson
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Amanda E Poste
- Department of Arctic Marine Biology, UiT, The Arctic University of Norway, 9019 Tromsø, Norway; Norwegian Institute for Water Research, 9007 Tromsø, Norway; Norwegian Institute for Nature Research, 9296 Tromsø, Norway.
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3
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Kokarev V, Zalota AK, Zuev A, Tiunov A, Kuznetsov P, Konovalova O, Rimskaya-Korsakova N. Opportunistic consumption of marine pelagic, terrestrial, and chemosynthetic organic matter by macrofauna on the Arctic shelf: a stable isotope approach. PeerJ 2023; 11:e15595. [PMID: 37404477 PMCID: PMC10315133 DOI: 10.7717/peerj.15595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/29/2023] [Indexed: 07/06/2023] Open
Abstract
Macrofauna can contribute substantially to the organic matter cycling on the seafloor, yet the role of terrestrial and chemosynthetic organic matter in the diets of microphagous (deposit and suspension) feeders is poorly understood. In the present study, we used stable isotopes of carbon and nitrogen to test the hypothesis that the terrestrial organic matter supplied with river runoff and local chemosynthetic production at methane seeps might be important organic matter sources for macrofaunal consumers on the Laptev Sea shelf. We sampled locations from three habitats with the presumed differences in organic matter supply: "Delta" with terrestrial inputs from the Lena River, "Background" on the northern part of the shelf with pelagic production as the main organic matter source, and "Seep" in the areas with detected methane seepage, where chemosynthetic production might be available. Macrobenthic communities inhabiting each of the habitats were characterized by a distinct isotopic niche, mostly in terms of δ13C values, directly reflecting differences in the origin of organic matter supply, while δ15N values mostly reflected the feeding group (surface deposit/suspension feeders, subsurface deposit feeders, and carnivores). We conclude that both terrestrial and chemosynthetic organic matter sources might be substitutes for pelagic primary production in the benthic food webs on the largely oligotrophic Laptev Sea shelf. Furthermore, species-specific differences in the isotopic niches of species belonging to the same feeding group are discussed, as well as the isotopic niches of the symbiotrophic tubeworm Oligobrachia sp. and the rissoid gastropod Frigidoalvania sp., which are exclusively associated with methane seeps.
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Affiliation(s)
- Valentin Kokarev
- Laboratory of Ecology of Coastal Bottom Communities, Shirshov Institute of Oceanology RAS, Moscow, Russia
| | - Anna K. Zalota
- Laboratory of Ecology of Coastal Bottom Communities, Shirshov Institute of Oceanology RAS, Moscow, Russia
| | - Andrey Zuev
- Laboratory of Soil Zoology and General Entomology, A.N. Severtsov Institute of Ecology and Evolution RAS, Moscow, Russia
| | - Alexei Tiunov
- Laboratory of Soil Zoology and General Entomology, A.N. Severtsov Institute of Ecology and Evolution RAS, Moscow, Russia
| | - Petr Kuznetsov
- Department of Invertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Olga Konovalova
- Centre of Marine Research, Lomonosov Moscow State University, Moscow, Russia
- National Research Tomsk State University, Tomsk, Russia
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4
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von Biela VR, Laske SM, Stanek AE, Brown RJ, Dunton KH. Borealization of nearshore fishes on an interior Arctic shelf over multiple decades. GLOBAL CHANGE BIOLOGY 2023; 29:1822-1838. [PMID: 36565055 DOI: 10.1111/gcb.16576] [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: 07/12/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 05/28/2023]
Abstract
Borealization is a type of community reorganization where Arctic specialists are replaced by species with more boreal distributions in response to climatic warming. The process of borealization is often exemplified by the northward range expansions and subsequent proliferation of boreal species on the Pacific and Atlantic inflow Arctic shelves (i.e., Bering/Chukchi and Barents seas, respectively). But the circumpolar nearshore distribution of Arctic-boreal fishes that predates recent warming suggests borealization is possible beyond inflow shelves. To examine this question, we revisited two nearshore lagoons in the eastern Alaska Beaufort Sea (Kaktovik and Jago lagoons, Arctic National Wildlife Refuge, Alaska, USA), a High Arctic interior shelf. We compared summer fish species assemblage, catch rate, and size distribution among three periods that spanned a 30-year record (baseline conditions, 1988-1991; moderate sea ice decline, 2003-2005; rapid sea ice decline, 2017-2019). Fish assemblages differed among periods in both lagoons, consistent with borealization. Among Arctic specialists, a clear decline in fourhorn sculpin (Myoxocephalus quadricornis, Kanayuq in Iñupiaq) occurred in both lagoons with 86%-90% lower catch rates compared with the baseline period. Among the Arctic-boreal species, a dramatic 18- to 19-fold increase in saffron cod (Eleginus gracilis, Uugaq) occurred in both lagoons. Fish size (length) distributions demonstrated increases in the proportion of larger fish for most species examined, consistent with increasing survival and addition of age-classes. These field data illustrate borealization of an Arctic nearshore fish community during a period of rapid warming. Our results agree with predictions that Arctic-boreal fishes (e.g., saffron cod) are well positioned to exploit the changing Arctic ecosystem. Another Arctic-boreal species, Dolly Varden (Salvelinus malma, Iqalukpik), appear to have already responded to warming by shifting from Arctic nearshore to shelf waters. More broadly, our findings suggest that areas of borealization could be widespread in the circumpolar nearshore.
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Affiliation(s)
| | - Sarah M Laske
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Ashley E Stanek
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Randy J Brown
- U.S. Fish and Wildlife Service, Fairbanks Field Office, Fairbanks, Alaska, USA
| | - Kenneth H Dunton
- Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, USA
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Ducklow H, Cimino M, Dunton KH, Fraser WR, Hopcroft RR, Ji R, Miller AJ, Ohman MD, Sosik HM. Marine Pelagic Ecosystem Responses to Climate Variability and Change. Bioscience 2022. [DOI: 10.1093/biosci/biac050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
abstract
The marine coastal region makes up just 10% of the total area of the global ocean but contributes nearly 20% of its total primary production and over 80% of fisheries landings. Unicellular phytoplankton dominate primary production. Climate variability has had impacts on various marine ecosystems, but most sites are just approaching the age at which ecological responses to longer term, unidirectional climate trends might be distinguished. All five marine pelagic sites in the US Long Term Ecological Research (LTER) network are experiencing warming trends in surface air temperature. The marine physical system is responding at all sites with increasing mixed layer temperatures and decreasing depth and with declining sea ice cover at the two polar sites. Their ecological responses are more varied. Some sites show multiple population or ecosystem changes, whereas, at others, changes have not been detected, either because more time is needed or because they are not being measured.
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Affiliation(s)
- Hugh Ducklow
- Columbia University , New York, New York, United States
| | - Megan Cimino
- University of California Santa Cruz , Santa Cruz, California, United States
| | - Kenneth H Dunton
- University of Texas, Port Aransas , Port Aransas, Texas, United States
| | - William R Fraser
- Polar Oceans Research Group, part of the Holtzman Wildlife Foundation , Farmington Mills, Michigan, United States
| | | | - Rubao Ji
- Woods Hole Oceanographic Institution , Woods Hole, Massachusetts, United States
| | - Arthur J Miller
- Scripps Institution of Oceanography , La Jolla, California, United States
| | - Mark D Ohman
- Scripps Institution of Oceanography , La Jolla, California, United States
| | - Heidi M Sosik
- Woods Hole Oceanographic Institution , Woods Hole, Massachusetts, United States
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6
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Skogsberg E, McGovern M, Poste A, Jonsson S, Arts MT, Varpe Ø, Borgå K. Seasonal pollutant levels in littoral high-Arctic amphipods in relation to food sources and terrestrial run-off. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 306:119361. [PMID: 35523379 DOI: 10.1016/j.envpol.2022.119361] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 03/09/2022] [Accepted: 04/23/2022] [Indexed: 06/14/2023]
Abstract
Increasing terrestrial run-off from melting glaciers and thawing permafrost to Arctic coastal areas is expected to facilitate re-mobilization of stored legacy persistent organic pollutants (POPs) and mercury (Hg), potentially increasing exposure to these contaminants for coastal benthic organisms. We quantified chlorinated POPs and Hg concentrations, lipid content and multiple dietary markers, in a littoral deposit-feeding amphipod Gammarus setosus and sediments during the melting period from April to August in Adventelva river estuary in Svalbard, a Norwegian Arctic Aarchipelago. There was an overall decrease in concentrations of ∑POPs from April to August (from 58 ± 23 to 13 ± 4 ng/g lipid weight; lw), Hg (from 5.6 ± 0.7 to 4.1 ± 0.5 ng/g dry weight; dw) and Methyl Hg (MeHg) (from 5 ± 1 to 0.8 ± 0.7 ng/g dw) in G. setosus. However, we observed a seasonal peak in penta- and hexachlorobenzene (PeCB and HCB) in May (2.44 ± 0.3 and 23.6 ± 1.7 ng/g lw). Sediment concentrations of POPs and Hg (dw) only partly correlated with the contaminant concentrations in G. setosus. Dietary markers, including fatty acids and carbon and nitrogen stable isotopes, indicated a diet of settled phytoplankton in May-July and a broader range of carbon sources after the spring bloom. Phytoplankton utilization and chlorobenzene concentrations in G. setosus exhibited similar seasonal patterns, suggesting a dietary uptake of chlorobenzenes that is delivered to the aquatic environment during spring snowmelt. The seasonal decrease in contaminant concentrations in G. setosus could be related to seasonal changes in dietary contaminant exposure and amphipod ecology. Furthermore, this decrease implies that terrestrial run-off is not a significant source of re-mobilized Hg and legacy POPs to littoral amphipods in the Adventelva river estuary during the melt season.
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Affiliation(s)
- Emelie Skogsberg
- University of Oslo, Department of Biosciences, Oslo, Norway; The University Centre in Svalbard, Department of Arctic Biology, Longyearbyen, Norway
| | - Maeve McGovern
- Norwegian Institute for Water Research, Oslo, Norway; The Arctic University of Norway, Tromsø, Norway
| | - Amanda Poste
- Norwegian Institute for Water Research, Oslo, Norway; The Arctic University of Norway, Tromsø, Norway
| | - Sofi Jonsson
- Stockholm University, Department of Environmental Science, Stockholm, Sweden
| | - Michael T Arts
- Ryerson University, Department of Chemistry and Biology, Toronto, M5B 2K3, Canada
| | - Øystein Varpe
- The University Centre in Svalbard, Department of Arctic Biology, Longyearbyen, Norway; Norwegian Institute for Nature Research, Bergen, Norway; University of Bergen, Department of Biological Sciences, Bergen, Norway
| | - Katrine Borgå
- University of Oslo, Department of Biosciences, Oslo, Norway.
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7
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Zinkann AC, Wooller MJ, O'Brien D, Iken K. Does feeding type matter? Contribution of organic matter sources to benthic invertebrates on the Arctic Chukchi Sea shelf. FOOD WEBS 2021. [DOI: 10.1016/j.fooweb.2021.e00205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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8
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Semi-Automated Semantic Segmentation of Arctic Shorelines Using Very High-Resolution Airborne Imagery, Spectral Indices and Weakly Supervised Machine Learning Approaches. REMOTE SENSING 2021. [DOI: 10.3390/rs13224572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Precise coastal shoreline mapping is essential for monitoring changes in erosion rates, surface hydrology, and ecosystem structure and function. Monitoring water bodies in the Arctic National Wildlife Refuge (ANWR) is of high importance, especially considering the potential for oil and natural gas exploration in the region. In this work, we propose a modified variant of the Deep Neural Network based U-Net Architecture for the automated mapping of 4 Band Orthorectified NOAA Airborne Imagery using sparsely labeled training data and compare it to the performance of traditional Machine Learning (ML) based approaches—namely, random forest, xgboost—and spectral water indices—Normalized Difference Water Index (NDWI), and Normalized Difference Surface Water Index (NDSWI)—to support shoreline mapping of Arctic coastlines. We conclude that it is possible to modify the U-Net model to accept sparse labels as input and the results are comparable to other ML methods (an Intersection-over-Union (IoU) of 94.86% using U-Net vs. an IoU of 95.05% using the best performing method).
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9
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Fraley KM, Robards MD, Rogers MC, Vollenweider J, Smith B, Whiting A, Jones T. Freshwater input and ocean connectivity affect habitats and trophic ecology of fishes in Arctic coastal lagoons. Polar Biol 2021. [DOI: 10.1007/s00300-021-02895-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Baker KD, Kellogg CTE, McClelland JW, Dunton KH, Crump BC. The Genomic Capabilities of Microbial Communities Track Seasonal Variation in Environmental Conditions of Arctic Lagoons. Front Microbiol 2021; 12:601901. [PMID: 33643234 PMCID: PMC7906997 DOI: 10.3389/fmicb.2021.601901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/04/2021] [Indexed: 11/30/2022] Open
Abstract
In contrast to temperate systems, Arctic lagoons that span the Alaska Beaufort Sea coast face extreme seasonality. Nine months of ice cover up to ∼1.7 m thick is followed by a spring thaw that introduces an enormous pulse of freshwater, nutrients, and organic matter into these lagoons over a relatively brief 2–3 week period. Prokaryotic communities link these subsidies to lagoon food webs through nutrient uptake, heterotrophic production, and other biogeochemical processes, but little is known about how the genomic capabilities of these communities respond to seasonal variability. Replicate water samples from two lagoons and one coastal site near Kaktovik, AK were collected in April (full ice cover), June (ice break up), and August (open water) to represent winter, spring, and summer, respectively. Samples were size fractionated to distinguish free-living and particle-attached microbial communities. Multivariate analysis of metagenomes indicated that seasonal variability in gene abundances was greater than variability between size fractions and sites, and that June differed significantly from the other months. Spring (June) gene abundances reflected the high input of watershed-sourced nutrients and organic matter via spring thaw, featuring indicator genes for denitrification possibly linked to greater organic carbon availability, and genes for processing phytoplankton-derived organic matter associated with spring blooms. Summer featured fewer indicator genes, but had increased abundances of anoxygenic photosynthesis genes, possibly associated with elevated light availability. Winter (April) gene abundances suggested low energy inputs and autotrophic bacterial metabolism, featuring indicator genes for chemoautotrophic carbon fixation, methane metabolism, and nitrification. Winter indicator genes for nitrification belonged to Thaumarchaeota and Nitrosomonadales, suggesting these organisms play an important role in oxidizing ammonium during the under-ice period. This study shows that high latitude estuarine microbial assemblages shift metabolic capabilities as they change phylogenetic composition between these extreme seasons, providing evidence that these communities may be resilient to large hydrological events in a rapidly changing Arctic.
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Affiliation(s)
- Kristina D Baker
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | | | - James W McClelland
- The University of Texas at Austin Marine Science Institute, Port Aransas, TX, United States
| | - Kenneth H Dunton
- The University of Texas at Austin Marine Science Institute, Port Aransas, TX, United States
| | - Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
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11
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Morata N, Michaud E, Poullaouec MA, Devesa J, Le Goff M, Corvaisier R, Renaud PE. Climate change and diminishing seasonality in Arctic benthic processes. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190369. [PMID: 32862805 PMCID: PMC7481667 DOI: 10.1098/rsta.2019.0369] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The iconic picture of Arctic marine ecosystems shows an intense pulse of biological productivity around the spring bloom that is sustained while fresh organic matter (OM) is available, after which ecosystem activity declines to basal levels in autumn and winter. We investigated seasonality in benthic biogeochemical cycling at three stations in a high Arctic fjord that has recently lost much of its seasonal ice-cover. Unlike observations from other Arctic locations, we find little seasonality in sediment community respiration and bioturbation rates, although different sediment reworking modes varied through the year. Nutrient fluxes did vary, suggesting that, although OM was processed at similar rates, seasonality in its quality led to spring/summer peaks in inorganic nitrogen and silicate fluxes. These patterns correspond to published information on seasonality in vertical flux at the stations. Largely ice-free Kongsfjorden has a considerable detrital pool in soft sediments which sustain benthic communities over the year. Sources of this include macroalgae and terrestrial runoff. Climate change leading to less ice cover, higher light availability and expanded benthic habitat may lead to more detrital carbon in the system, dampening the quantitative importance of seasonal pulses of phytodetritus to seafloor communities in some areas of the Arctic. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
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Affiliation(s)
- Nathalie Morata
- CNRS, Univ Brest, IRD, Ifremer, LEMAR, 29280 Plouzane, France
- Akvaplan-niva AS, Fram Centre, PO Box 6606 Langnes, 9296 Tromsø, Norway
| | - Emma Michaud
- CNRS, Univ Brest, IRD, Ifremer, LEMAR, 29280 Plouzane, France
- e-mail:
| | | | - Jérémy Devesa
- CNRS, Univ Brest, IRD, Ifremer, LEMAR, 29280 Plouzane, France
| | - Manon Le Goff
- CNRS, Univ Brest, IRD, Ifremer, LEMAR, 29280 Plouzane, France
| | | | - Paul E. Renaud
- Akvaplan-niva AS, Fram Centre, PO Box 6606 Langnes, 9296 Tromsø, Norway
- University Centre in Svalbard, 9171 Longyearbyen, Norway
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12
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Groundwater as a major source of dissolved organic matter to Arctic coastal waters. Nat Commun 2020; 11:1479. [PMID: 32198391 PMCID: PMC7083844 DOI: 10.1038/s41467-020-15250-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 02/25/2020] [Indexed: 11/21/2022] Open
Abstract
Groundwater is projected to become an increasing source of freshwater and nutrients to the Arctic Ocean as permafrost thaws, yet few studies have quantified groundwater inputs to Arctic coastal waters under contemporary conditions. New measurements along the Alaska Beaufort Sea coast show that dissolved organic carbon and nitrogen (DOC and DON) concentrations in supra-permafrost groundwater (SPGW) near the land-sea interface are up to two orders of magnitude higher than in rivers. This dissolved organic matter (DOM) is sourced from readily leachable organic matter in surface soils and deeper centuries-to millennia-old soils that extend into thawing permafrost. SPGW delivers approximately 400–2100 m3 of freshwater, 14–71 kg of DOC, and 1–4 kg of DON to the coastal ocean per km of shoreline per day during late summer. These substantial fluxes are expected to increase as massive stocks of frozen organic matter in permafrost are liberated in a warming Arctic. In this study, the authors show that water flowing through thawed soils below the tundra surface (supra-permafrost groundwater) can be a major source of dissolved organic matter (DOM) to Arctic coastal waters during the summer. This DOM contains leachates from old soil carbon stocks, including potential contributions from thawing permafrost.
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13
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Hartwell SI, Lomax T, Dasher D. Characterization of sediment contaminants in Arctic lagoons and estuaries. MARINE POLLUTION BULLETIN 2020; 152:110873. [PMID: 32479272 DOI: 10.1016/j.marpolbul.2019.110873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 12/24/2019] [Accepted: 12/31/2019] [Indexed: 06/11/2023]
Abstract
Baseline characterizations of estuarine sediments in Chukchi and Beaufort Seas, were conducted. Concentrations of 194 organic and elemental chemicals were analyzed in sediment and fish, plus stable isotopes of carbon and nitrogen. The estuaries are shallow embayments, with little shoreline relief. The water columns were turbid, high salinity, and not stratified. Concentrations of arsenic and nickel were elevated throughout the region. Arsenic in fish tissue was elevated. Concentrations of PAHs were relatively high for pristine locations, but did not include petroleum hydrocarbons. Characteristics of PAHs indicate large contributions of terrestrial organic matter. With the exception of Peard Bay, all the estuaries reflected the strong influence of terrestrial plant input with low δo/oo values for carbon and nitrogen. Chlorinated pesticides and PCBs were uniformly low, but detectable in fish tissue. PCB and cyclodiene concentrations were half that seen in southeast Bristol Bay. Hexachlorobenzene was detected in all fish samples.
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Affiliation(s)
- S Ian Hartwell
- NOAA/NOS/National Centers for Coastal Ocean Science, Stressor Detection & Impacts Division Monitoring & Assessment Branch, 1305 East West Hwy. (SSMC-4, N/SCI-1), Silver Spring, MD 20910, United States of America.
| | - Terri Lomax
- Alaska Department of Environmental Conservation (ADEC), 555 Cordova St., Anchorage, AK 99501, United States of America
| | - Doug Dasher
- University of Alaska Fairbanks, Institute of Marine Science, 905 N. Koyukuk Dr. 245 O'Neill Building, Fairbanks, AK 99775-7220, United States of America
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14
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Kellogg CTE, McClelland JW, Dunton KH, Crump BC. Strong Seasonality in Arctic Estuarine Microbial Food Webs. Front Microbiol 2019; 10:2628. [PMID: 31849850 PMCID: PMC6896822 DOI: 10.3389/fmicb.2019.02628] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/29/2019] [Indexed: 11/17/2022] Open
Abstract
Microbial communities in the coastal Arctic Ocean experience extreme variability in organic matter and inorganic nutrients driven by seasonal shifts in sea ice extent and freshwater inputs. Lagoons border more than half of the Beaufort Sea coast and provide important habitats for migratory fish and seabirds; yet, little is known about the planktonic food webs supporting these higher trophic levels. To investigate seasonal changes in bacterial and protistan planktonic communities, amplicon sequences of 16S and 18S rRNA genes were generated from samples collected during periods of ice-cover (April), ice break-up (June), and open water (August) from shallow lagoons along the eastern Alaska Beaufort Sea coast from 2011 through 2013. Protist communities shifted from heterotrophic to photosynthetic taxa (mainly diatoms) during the winter–spring transition, and then back to a heterotroph-dominated summer community that included dinoflagellates and mixotrophic picophytoplankton such as Micromonas and Bathycoccus. Planktonic parasites belonging to Syndiniales were abundant under ice in winter at a time when allochthonous carbon inputs were low. Bacterial communities shifted from coastal marine taxa (Oceanospirillaceae, Alteromonadales) to estuarine taxa (Polaromonas, Bacteroidetes) during the winter-spring transition, and then to oligotrophic marine taxa (SAR86, SAR92) in summer. Chemolithoautotrophic taxa were abundant under ice, including iron-oxidizing Zetaproteobacteria. These results suggest that wintertime Arctic bacterial communities capitalize on the unique biogeochemical gradients that develop below ice near shore, potentially using chemoautotrophic metabolisms at a time when carbon inputs to the system are low. Co-occurrence networks constructed for each season showed that under-ice networks were dominated by relationships between parasitic protists and other microbial taxa, while spring networks were by far the largest and dominated by bacteria-bacteria co-occurrences. Summer networks were the smallest and least connected, suggesting a more detritus-based food web less reliant on interactions among microbial taxa. Eukaryotic and bacterial community compositions were significantly related to trends in concentrations of stable isotopes of particulate organic carbon and nitrogen, among other physiochemical variables such as dissolved oxygen, salinity, and temperature. This suggests the importance of sea ice cover and terrestrial carbon subsidies in contributing to seasonal trends in microbial communities in the coastal Beaufort Sea.
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Affiliation(s)
| | - James W McClelland
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX, United States
| | - Kenneth H Dunton
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX, United States
| | - Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
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Rowe AG, Iken K, Blanchard AL, O'Brien DM, Døving Osvik R, Uradnikova M, Wooller MJ. Sources of primary production to Arctic bivalves identified using amino acid stable carbon isotope fingerprinting . ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2019; 55:366-384. [PMID: 31185743 DOI: 10.1080/10256016.2019.1620742] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/02/2019] [Indexed: 06/09/2023]
Abstract
Benthic invertebrates are a crucial trophic link in Arctic marine food webs. However, estimates of the contribution of different primary production sources sustaining these organisms are not well characterised. We measured the stable carbon isotope values (δ13C) of essential amino acids (EAAs) in muscle tissue from two common bivalve genera (Macoma spp. and Astarte spp.) collected in Hanna Shoal in the northeastern Chukchi Sea. Mixing models comparing the δ13CEAA fingerprints of the bivalves to a suite of primary production endmembers revealed relatively high contributions of EAAs from phytoplankton and bacteria in both species. We also examined whether δ13CEAA fingerprints could be produced from the EAAs preserved in bivalve shells, which could allow primary production sources to be estimated from ancient bivalve shells. The δ13CEAA fingerprints from a suite of paired modern bivalve shells and muscle from Macoma calcarea from across the Chukchi Sea revealed a correspondence between the estimates of the dominant primary production source of EAAs derived from analyses of these two tissue types. Our findings indicate that δ13CEAA fingerprinting of marine bivalves can be used to examine dominant organic matter sources in the Arctic marine benthos in recent years as well as in deeper time.
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Affiliation(s)
- Audrey G Rowe
- a Department of Marine Biology, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks , Fairbanks , Alaska , USA
- b Alaska Stable Isotope Facility, Water and Environmental Research Center, University of Alaska Fairbanks , Fairbanks , Alaska , USA
| | - Katrin Iken
- a Department of Marine Biology, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks , Fairbanks , Alaska , USA
| | - Arny L Blanchard
- a Department of Marine Biology, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks , Fairbanks , Alaska , USA
| | - Diane M O'Brien
- c Institute of Arctic Biology, University of Alaska Fairbanks , Fairbanks , Alaska , USA
| | - Renate Døving Osvik
- d The Norwegian College of Fishery Science, UiT Norway's Arctic University , Tromsø , Norway
| | - Martina Uradnikova
- d The Norwegian College of Fishery Science, UiT Norway's Arctic University , Tromsø , Norway
| | - Matthew J Wooller
- a Department of Marine Biology, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks , Fairbanks , Alaska , USA
- b Alaska Stable Isotope Facility, Water and Environmental Research Center, University of Alaska Fairbanks , Fairbanks , Alaska , USA
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