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Aqdam MM, Baltzer JL, Branfireun BA, Low G, Low M, Swanson HK. Can remotely sensed catchment to lake area ratios predict mercury levels in subarctic fishes? ENVIRONMENTAL RESEARCH 2024; 260:119545. [PMID: 38986798 DOI: 10.1016/j.envres.2024.119545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/28/2024] [Accepted: 07/01/2024] [Indexed: 07/12/2024]
Abstract
Mercury concentrations ([Hg]) in fish reflect a complex array of interacting biogeochemical and ecological variables. In northern regions where fish are a critical subsistence food, understanding and predicting fish [Hg] can be particularly difficult, largely due to a paucity of comprehensive data associated with the logistical challenges of field sampling. Building on previous work where we elucidated causal relationships between fish [Hg] and a variety of catchment, water quality, and ecological variables in subarctic lakes, we investigated whether using only ratios of catchment area to lake area (CA:LA) can predict [Hg] in northern freshwater fish species. As CA:LA can be sensed remotely, they may be more feasible and practical to obtain than field data in far northern regions. Our study included thirteen remote lakes that represent a CA:LA gradient of 6.2-423.5 within an ∼66,000 km2 subarctic region of Northwest Territories, Canada. We found that size-standardized [Hg] in three widespread fish species, including Lake Whitefish (Coregonus clupeaformis), Walleye (Sander vitreus), and Northern Pike (Esox lucius), were significantly and positively related to CA:LA (p < 0.007, r2 = 67-80%), indicating higher fish [Hg] in smaller lakes surrounded by relatively larger catchments. Our findings provide compelling evidence that remotely sensed CA:LA can be used to predict [Hg] in northern fishes and aid in prioritizing understudied and subsistence fishing lakes of the Canadian subarctic for [Hg] monitoring programs.
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Affiliation(s)
- Mehdi M Aqdam
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada; Azimuth Consulting Group Inc., Vancouver, BC, Canada.
| | | | | | - George Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Mike Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Heidi K Swanson
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada.
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2
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Baldwin AK, Janssen SE, Tate MT, Poulin BA, Yoder AM, Naymik J, Larsen C, Hoovestol C, Krabbenhoft DP. Mercury sources and budget for the Snake River above a hydroelectric reservoir complex. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167961. [PMID: 37865255 DOI: 10.1016/j.scitotenv.2023.167961] [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: 08/16/2023] [Revised: 10/13/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Understanding sources of mercury (Hg) and methylmercury (MeHg) to a water body is critical for management but is often complicated by poorly characterized Hg inputs and in situ processes, such as inorganic Hg methylation. In this study, we determined inorganic Hg and MeHg concentrations and loads (filter-passing and particulate fractions) for a semi-arid 164-kilometer stretch of the Snake River above the Hells Canyon Complex, a Hg-impaired hydroelectric reservoir complex on the Idaho-Oregon border, and used water quality measurements and Hg stable isotope ratios to create a comprehensive Hg source budget for the river. Results show that whereas most of the streamflow to the study reach comes from the main branch of the Snake River (i.e., the upstream watershed), major tributaries within the study reach contribute a greater proportion of inorganic Hg and MeHg loads. Mercury stable-isotope analyses highlight that Hg within the tributaries is predominantly associated with geologic deposits and snowmelt sources, the latter reflecting wet deposition. Surprisingly, irrigation return drains contribute 40-50 % of particulate inorganic Hg loads despite being ≤4.3 % of the overall water budget. Together, tributaries and irrigation return drains account for 97-100 % of the inorganic Hg and streamflow to the study reach, but ~65 % of the MeHg, indicating in-stream and riparian methylation may be an important and previously unrecognized source of MeHg. Streamflow, total suspended solids, dissolved organic carbon, and agricultural land cover were found to be important controls on the mobilization and transport of different Hg species and fractions. This study represents the first fluvial budget for Hg in the Snake River that accounts for particulate and filter-passing Hg species from both major tributaries and irrigation return drains, and expands our understanding of Hg sources and methylation processes within semi-arid environments. This information is critical to inform management decisions related to elevated Hg burdens in biota.
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Affiliation(s)
- Austin K Baldwin
- U.S. Geological Survey, Idaho Water Science Center, United States of America.
| | - Sarah E Janssen
- U.S. Geological Survey, Upper Midwest Water Science Center, United States of America
| | - Michael T Tate
- U.S. Geological Survey, Upper Midwest Water Science Center, United States of America
| | - Brett A Poulin
- Department of Environmental Toxicology, University of California at Davis, United States of America
| | - Alysa M Yoder
- U.S. Geological Survey, Idaho Water Science Center, United States of America
| | | | | | | | - David P Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, United States of America
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3
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Moslemi-Aqdam M, Low G, Low M, Laird BD, Branfireun BA, Swanson HK. Estimates, spatial variability, and environmental drivers of mercury biomagnification rates through lake food webs in the Canadian subarctic. ENVIRONMENTAL RESEARCH 2023; 217:114835. [PMID: 36400218 DOI: 10.1016/j.envres.2022.114835] [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: 08/12/2022] [Revised: 10/27/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
Biomagnification of mercury (Hg) through lake food webs is understudied in rapidly changing northern regions, where wild-caught subsistence fish are critical to food security. We investigated estimates and among-lake variability of Hg biomagnification rates (BMR), relationships between Hg BMR and Hg levels in subsistence fish, and environmental drivers of Hg BMR in ten remote subarctic lakes in Northwest Territories, Canada. Lake-specific linear regressions between Hg concentrations (total Hg ([THg]) in fish and methyl Hg ([MeHg]) in primary consumers) and baseline-adjusted δ15N ratios were significant (p < 0.001, r2 = 0.58-0.88), indicating biomagnification of Hg through food webs of all studied lakes. Quantified using the slope of Hg-δ15N regressions, Hg BMR ranged from 0.16 to 0.25, with mean ± standard deviation of 0.20 ± 0.03). Using fish [MeHg] rather than [THg] lowered estimates of Hg BMR by ∼10%, suggesting that the use of [THg] as a proxy for [MeHg] in fish can influence estimates of Hg BMR. Among-lake variability of size-standardized [THg] in resident fish species from different trophic guilds, namely Lake Whitefish (Coregonus clupeaformis) and Northern Pike (Esox lucius), was not significantly explained by among-lake variability in Hg BMR. Stepwise multiple regressions indicated that among-lake variability of Hg BMR was best explained by a positive relationship with catchment forest cover (p = 0.009, r2 = 0.59), likely reflecting effects of forest cover on water chemistry of downstream lakes and ultimately, concentrations of biomagnifying MeHg (and percent MeHg of total Hg) in resident biota. These findings improve our understanding of Hg biomagnification in remote subarctic lakes.
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Affiliation(s)
| | - George Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Mike Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Brian D Laird
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | | | - Heidi K Swanson
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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Li P, Wang R, Kainz MJ, Yin D. Algal Density Controls the Spatial Variations in Hg Bioconcentration and Bioaccumulation at the Base of the Pelagic Food Web of Lake Taihu, China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14528-14538. [PMID: 36194456 DOI: 10.1021/acs.est.2c05625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Algal density can significantly impact mercury (Hg) bioaccumulation and biomagnification in aquatic food webs, but the underlying mechanisms remain controversial especially in subtropical and tropical regions. We conducted a comprehensive field study on Hg bioconcentration in phytoplankton and bioaccumulation in size-fractionated zooplankton across 17 sampling sites in Lake Taihu, a large shallow lake in eastern China with large spatial differences in algal density. The higher algal density in the northern sites is highly associated with the lower THg bioconcentration factor (BCF) in phytoplankton and lower THg bioaccumulation factor (BAF) in zooplankton. The low Hg BCFs or BAFs at productive sites could not be explained by algal bloom dilution but attributed to the low Hg bioavailability, which is highly associated with the elevated pH levels at productive sites. The smaller body size of the dominant zooplankton species at higher algal density sites also contributed to their lower Hg bioaccumulation. Importantly, we provide evidence that high algal density is associated with a low proportion of methylmercury (MeHg) in total Hg (% MeHg) in phytoplankton, which is further transferred to zooplankton. Such a low THg BCF or BAF and low % MeHg in plankton at high algal density sites hamper the entry of Hg into the pelagic food webs, which are important but yet underestimated driving forces for the low Hg contents in pelagic fish that are commonly observed in anthropogenic-impacted eutrophic lakes in subtropical regions.
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Affiliation(s)
- Pengwei Li
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai200092, China
| | - Rui Wang
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai200092, China
| | - Martin J Kainz
- WasserCluster Lunz - Biologische Station, Inter-University Center for Aquatic Ecosystem Research, A-3293Lunz am See, Austria
- Department of Biomedical Research, Danube University Krems, A-3500Krems, Austria
| | - Daqiang Yin
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai200092, China
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Moslemi-Aqdam M, Baker LF, Baltzer JL, Branfireun BA, Evans MS, Laird BD, Low G, Low M, Swanson HK. Understanding among-lake variability of mercury concentrations in Northern Pike (Esox lucius): A whole-ecosystem study in subarctic lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153430. [PMID: 35090925 DOI: 10.1016/j.scitotenv.2022.153430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/04/2022] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Mercury concentrations ([Hg]) in fish reflect complex biogeochemical and ecological interactions that occur at a range of spatial and biological scales. Elucidating these interactions is crucial to understanding and predicting fish [Hg], particularly at northern latitudes, where environmental perturbations are having profound effects on land-water-animal interactions, and where fish are a critical subsistence food source. Using data from eleven subarctic lakes that span an area of ~60,000 km2 in the Dehcho Region of Northwest Territories (Canada), we investigated how trophic ecology and growth rates of fish, lake water chemistry, and catchment characteristics interact to affect [Hg] in Northern Pike (Esox lucius), a predatory fish of widespread subsistence and commercial importance. Results from linear regression and piecewise structural equation models showed that 83% of among-lake variability in Northern Pike [Hg] was explained by fish growth rates (negative) and concentrations of methyl Hg ([MeHg]) in benthic invertebrates (positive). These variables were in turn influenced by concentrations of dissolved organic carbon, MeHg (water), and total Hg (sediment) in lakes, which were ultimately driven by catchment characteristics. Lakes in relatively larger catchments and with more temperate/subpolar needleleaf and mixed forests had higher [Hg] in Northern Pike. Our results provide a plausible mechanistic understanding of how interacting processes at scales ranging from whole catchments to individual organisms influence fish [Hg], and give insight into factors that could be considered for prioritizing lakes for monitoring in subarctic regions.
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Affiliation(s)
| | - Leanne F Baker
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | | | | | - Marlene S Evans
- Water Science and Technology Directorate, Environment and Climate Change Canada, Saskatoon, SK, Canada
| | - Brian D Laird
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - George Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Mike Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Heidi K Swanson
- Department of Biology, University of Waterloo, Waterloo, ON, Canada; Water Institute, University of Waterloo, Waterloo, ON, Canada
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Jung E, Kim H, Yun D, Rahman MM, Lee JH, Kim S, Kim CK, Han S. Importance of hydraulic residence time for methylmercury accumulation in sediment and fish from artificial reservoirs. CHEMOSPHERE 2022; 293:133545. [PMID: 34998844 DOI: 10.1016/j.chemosphere.2022.133545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Excessive methylmercury (MeHg) accumulation in dietary fish is a global concern due to its harmful effects on human health, however, environmental factors affecting MeHg accumulation in reservoir ecosystems are not clearly known. In this study, we aim to identify the main sources of MeHg in the water column and the critical factors related to MeHg concentration and methylation rate constant (km) in sediment and total Hg concentration in fish using five-year (2016-2020) monitoring data of the five artificial reservoirs. The preliminary mass budgets constructed using the measurement and online data showed that sediment transport dominated over runoff in the long residence time reservoirs (400-475 days), while runoff dominated over sediment transport in the short residence time reservoirs (10 days). Whereas the sediment km showed a comparable variation with the algal biomass, the sediment MeHg concentration and the length-normalized Hg concentration in the barbel steed and bluegill increased in the longer residence time reservoirs with lower algal biomass. As MeHg accumulation in sediment and fish tends to increase in the slowly overturning reservoirs, the hydraulic residence time should be carefully managed to meet the best protection of human health from chronic Hg exposure by fish consumption.
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Affiliation(s)
- Eunji Jung
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyogyeong Kim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Daseul Yun
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Md Moklesur Rahman
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Jong-Hyeon Lee
- Environmental Human Research & Consulting (EHR&C), Incheon, 22689, Republic of Korea
| | - Suhyun Kim
- Environmental Human Research & Consulting (EHR&C), Incheon, 22689, Republic of Korea
| | - Chan-Kook Kim
- Marine Environment Research Institute, OCEANIC C&T Co., Ltd, Kangwon, 25601, Republic of Korea
| | - Seunghee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
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Twining CW, Razavi NR, Brenna JT, Dzielski SA, Gonzalez ST, Lawrence P, Cleckner LB, Flecker AS. Emergent Freshwater Insects Serve as Subsidies of Methylmercury and Beneficial Fatty Acids for Riparian Predators Across an Agricultural Gradient. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5868-5877. [PMID: 33878866 DOI: 10.1021/acs.est.0c07683] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Aquatic-to-terrestrial subsidies have the potential to provide riparian consumers with benefits in terms of physiologically important organic compounds like omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs). However, they also have a "dark side" in the form of exposure to toxicants such as mercury. Human land use intensity may also determine whether subsidies provide benefits or come at a cost for riparian predators. We sampled insects as well as Eastern Phoebe (Sayornis phoebe) chicks in 2015-2016 within the southern Finger Lakes region to understand how food quality, in terms of n-3 LCPUFAs and methylmercury (MeHg), of emergent freshwater insects compared with that of terrestrial insects and how land use affected the quality of prey, predator diet composition, and MeHg exposure. Across the landscape, freshwater insects had a significantly higher percentage of the n-3 LCPUFA eicosapentaenoic acid (EPA) compared to terrestrial insects and contained significantly more MeHg than terrestrial insects did. In spite of differences in MeHg concentrations between aquatic and terrestrial insects, chick MeHg concentrations were not related to diet composition. Instead, chick MeHg concentrations increased with several metrics of human land use intensity, including percent agriculture. Our findings suggest that freshwater subsidies provide predators with both risks and benefits, but that predator MeHg exposure can vary with human land use intensity.
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Affiliation(s)
- Cornelia W Twining
- Max Planck Institute of Animal Behavior 78315 Radolfzell, Germany
- Limnological Institute, University of Konstanz 78464 Konstanz, Germany
| | - N Roxanna Razavi
- Department of Environmental Biology, State University of New York College of Environmental Science and Forestry Syracuse, New York 13210, United States
| | - J Thomas Brenna
- Division of Nutritional Sciences, Cornell University Ithaca, New York 14850, United States
- University of Texas, Austin, Dell Pediatric Research Center Austin, Texas 78712, United States
| | - Sarah A Dzielski
- Department of Environmental Biology, State University of New York College of Environmental Science and Forestry Syracuse, New York 13210, United States
| | - Sara T Gonzalez
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz Santa Cruz, California 95064, United States
| | - Peter Lawrence
- Division of Nutritional Sciences, Cornell University Ithaca, New York 14850, United States
| | - Lisa B Cleckner
- Hobart and William Smith Colleges, Finger Lakes Institute Geneva, New York 14456, United States
| | - Alexander S Flecker
- Department of Ecology and Evolutionary Biology, Cornell University Ithaca, New York 14850, United States
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Evers DC, Sauer AK, Burns DA, Fisher NS, Bertok DC, Adams EM, Burton MEH, Driscoll CT. A synthesis of patterns of environmental mercury inputs, exposure and effects in New York State. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1565-1589. [PMID: 33170395 PMCID: PMC7661403 DOI: 10.1007/s10646-020-02291-4] [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] [Accepted: 10/14/2020] [Indexed: 05/15/2023]
Abstract
Mercury (Hg) pollution is an environmental problem that adversely affects human and ecosystem health at local, regional, and global scales-including within New York State. More than two-thirds of the Hg currently released to the environment originates, either directly or indirectly, from human activities. Since the early 1800s, global atmospheric Hg concentrations have increased by three- to eight-fold over natural levels. In the U.S., atmospheric emissions and point-source releases to waterways increased following industrialization into the mid-1980s. Since then, water discharges have largely been curtailed. As a result, Hg emissions, atmospheric concentrations, and deposition over the past few decades have declined across the eastern U.S. Despite these decreases, Hg pollution persists. To inform policy efforts and to advance public understanding, the New York State Energy Research and Development Authority (NYSERDA) sponsored a scientific synthesis of information on Hg in New York State. This effort includes 23 papers focused on Hg in atmospheric deposition, water, fish, and wildlife published in Ecotoxicology. New York State experiences Hg contamination largely due to atmospheric deposition. Some landscapes are inherently sensitive to Hg inputs driven by the transport of inorganic Hg to zones of methylation, the conversion of inorganic Hg to methylmercury, and the bioaccumulation and biomagnification along food webs. Mercury concentrations exceed human and ecological risk thresholds in many areas of New York State, particularly the Adirondacks, Catskills, and parts of Long Island. Mercury concentrations in some biota have declined in the Eastern Great Lakes Lowlands and the Northeastern Highlands over the last four decades, concurrent with decreases in water releases and air emissions from regional and U.S. sources. However, widespread changes have not occurred in other ecoregions of New York State. While the timing and magnitude of the response of Hg levels in biota varies, policies expected to further diminish Hg emissions should continue to decrease Hg concentrations in food webs, yielding benefits to the fish, wildlife, and people of New York State. Anticipated improvements in the Hg status of aquatic ecosystems are likely to be greatest for inland surface waters and should be roughly proportional to declines in atmospheric Hg deposition. Efforts that advance recovery from Hg pollution in recent years have yielded significant progress, but Hg remains a pollutant of concern. Indeed, due to this extensive compilation of Hg observations in biota, it appears that the extent and intensity of the contamination on the New York landscape and waterscape is greater than previously recognized. Understanding the extent of Hg contamination and recovery following decreases in atmospheric Hg deposition will require further study, underscoring the need to continue existing monitoring efforts.
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Affiliation(s)
- D C Evers
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA.
| | - A K Sauer
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA
- Syracuse University, Syracuse, NY, 13244, USA
| | - D A Burns
- U.S. Geological Survey, Troy, NY, 12180, USA
| | - N S Fisher
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794, USA
| | - D C Bertok
- New York State Energy Research and Development Authority, Albany, NY, 12203, USA
| | - E M Adams
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA
| | - M E H Burton
- Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA
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