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Casas-Ruiz JP, Bodmer P, Bona KA, Butman D, Couturier M, Emilson EJS, Finlay K, Genet H, Hayes D, Karlsson J, Paré D, Peng C, Striegl R, Webb J, Wei X, Ziegler SE, Del Giorgio PA. Integrating terrestrial and aquatic ecosystems to constrain estimates of land-atmosphere carbon exchange. Nat Commun 2023; 14:1571. [PMID: 36944700 PMCID: PMC10030657 DOI: 10.1038/s41467-023-37232-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 03/01/2023] [Indexed: 03/23/2023] Open
Abstract
In this Perspective, we put forward an integrative framework to improve estimates of land-atmosphere carbon exchange based on the accumulation of carbon in the landscape as constrained by its lateral export through rivers. The framework uses the watershed as the fundamental spatial unit and integrates all terrestrial and aquatic ecosystems as well as their hydrologic carbon exchanges. Application of the framework should help bridge the existing gap between land and atmosphere-based approaches and offers a platform to increase communication and synergy among the terrestrial, aquatic, and atmospheric research communities that is paramount to advance landscape carbon budget assessments.
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Affiliation(s)
- Joan P Casas-Ruiz
- Research Group on Ecology of Inland Waters (GRECO), Institute of Aquatic Ecology, University of Girona, Girona, Spain.
| | - Pascal Bodmer
- Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Kelly Ann Bona
- Environment and Climate Change Canada, Gatineau, QC, Canada
| | - David Butman
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Mathilde Couturier
- Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | | | | | - Hélène Genet
- University of Alaska Fairbanks, Fairbanks, AK, USA
| | | | | | - David Paré
- Natural Resources Canada, Québec, QC, Canada
| | - Changhui Peng
- Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Rob Striegl
- United States Geological Survey, Boulder, CO, USA
| | - Jackie Webb
- Centre for Regional and Rural Futures (CeRRF), Faculty of Science, Engineering and Built Environment, Deakin University, Griffith, NSW, Australia
| | | | - Susan E Ziegler
- Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Paul A Del Giorgio
- Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
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Matthias BG, Hrabik TR, Hoffman JC, Gorman OT, Seider MJ, Sierszen ME, Vinson MR, Yule DL, Yurista PM. Trophic transfer efficiency in the Lake Superior food web: assessing the impacts of non-native species. JOURNAL OF GREAT LAKES RESEARCH 2021; 47:1146-1158. [PMID: 35520458 PMCID: PMC9067395 DOI: 10.1016/j.jglr.2021.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ecosystem-based management relies on understanding how perturbations influence ecosystem structure and function (e.g., invasive species, exploitation, abiotic changes). However, data on unimpacted systems are scarce, therefore, we often rely on impacted systems to make inferences about 'natural states.' Among the Laurentian Great Lakes, Lake Superior provides a unique case study to address non-native species impacts because the food web is dominated by native species. Additionally, Lake Superior is both vertically (benthic versus pelagic) and horizontally (nearshore versus offshore) structured by depth, providing an opportunity to compare the function of these sub-food webs. We developed an updated Lake Superior EcoPath model using data from the 2005/2006 lake-wide multi-agency surveys covering multiple trophic levels. We then compared trophic transfer efficiency (TTE) to previously published EcoPath models. Finally, we compared ecosystem function of the 2005/2006 ecosystem to that with non-native linkages removed and compared native versus non-native species-specific approximations of TTE and trophic flow. Lake Superior was relatively efficient (TTE = 0.14) compared to systems reported in a global review (average TTE = 0.09) and the microbial loop was highly efficient (TTE > 0.20). Non-native species represented a very small proportion (<0.01%) of total biomass and were generally more efficient and had higher trophic flow compared to native species. Our results provide valuable insight into the importance of the microbial loop and represent a baseline estimate of non-native species impacts on Lake Superior. Finally, this work is a starting point for further model development to predict future changes in the Lake Superior ecosystem.
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Affiliation(s)
- B G Matthias
- Biology Department, University of Minnesota Duluth, 1035 Kirby Drive, 207 Swenson Science Building, Duluth, MN 55812, USA
| | - T R Hrabik
- Biology Department, University of Minnesota Duluth, 1035 Kirby Drive, 207 Swenson Science Building, Duluth, MN 55812, USA
| | - J C Hoffman
- US Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Boulevard, Duluth, MN 55804, USA
| | - O T Gorman
- US Geological Survey, Great Lakes Science Center, Lake Superior Biological Station, 2800 Lake Shore Dr. East, Ashland, WI 54806, USA
| | - M J Seider
- US Fish and Wildlife Service, Ashland Fish and Wildlife Office, 2800 Lake Shore Dr. East, Ashland, WI 54806, USA
| | - M E Sierszen
- US Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Boulevard, Duluth, MN 55804, USA
| | - M R Vinson
- US Geological Survey, Great Lakes Science Center, Lake Superior Biological Station, 2800 Lake Shore Dr. East, Ashland, WI 54806, USA
| | - D L Yule
- US Geological Survey, Great Lakes Science Center, Lake Superior Biological Station, 2800 Lake Shore Dr. East, Ashland, WI 54806, USA
| | - P M Yurista
- US Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Boulevard, Duluth, MN 55804, USA
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Chen J, Yang H, Zeng Y, Guo J, Song Y, Ding W. Combined use of radiocarbon and stable carbon isotope to constrain the sources and cycling of particulate organic carbon in a large freshwater lake, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:27-38. [PMID: 29287210 DOI: 10.1016/j.scitotenv.2017.12.275] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/09/2017] [Accepted: 12/23/2017] [Indexed: 06/07/2023]
Abstract
The concentrations and isotopic compositions of dissolved inorganic carbon (DIC) and particulate organic carbon (POC) were measured in order to better constrain the sources and cycling of POC in Lake Fuxian, the largest deep freshwater lake in China. Model results based on the combined δ13C and Δ14C, showed that the average lake-wide contributions of autochthonous POC, terrestrial POC, and resuspended sediment POC to the bulk POC in Lake Fuxian were 61%, 22%, and 17%, respectively. This indicated autochthonous POC might play a dominant role in sustaining large oligotrophic lake ecosystem. A mean 17% contribution of resuspended sediment POC to the bulk POC implied that sediment might have more significant influence on aquatic environment and ecosystem than previously recognized in large deep lakes. The contributions of different sources POC to the water-column POC were a function of the initial composition of the source materials, photosynthesis, physical regime of the lake, sediment resuspension, respiration and degradation of organic matter, and were affected indirectly by environmental factors such as light, temperature, DO, wind speed, turbidity, and nutrient concentration. This study is not only the first systematic investigation on the radiocarbon and stable isotope compositions of POC in large deep freshwater lake in China, but also one of the most extensive radiocarbon studies on the ecosystem of any great lakes in the world. The unique data constrain relative influences of autochthonous POC, terrestrial POC, and resuspended sediment POC, and deepen the understanding of the POC cycling in large freshwater lakes. This study is far from comprehensive, but it serves to highlight the potential of combined radiocarbon and stable carbon isotope for constraining the sources and cycling of POC in large lake system. More radiocarbon investigations on the water-column POC and the aquatic food webs are necessary to illuminate further the fate of autochthonous POC, terrestrial POC, and resuspended sediment POC, and their eco-environmental effects.
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Affiliation(s)
- Jingan Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China.
| | - Haiquan Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Yan Zeng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Jianyang Guo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Yilong Song
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Wei Ding
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
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Cooney EM, McKinney P, Sterner R, Small GE, Minor EC. Tale of Two Storms: Impact of Extreme Rain Events on the Biogeochemistry of Lake Superior. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES 2018; 123:1719-1731. [PMID: 30800557 PMCID: PMC6381994 DOI: 10.1029/2017jg004216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 04/22/2018] [Indexed: 06/09/2023]
Abstract
Climate change is expected to profoundly affect the Great Lakes region of North America. An increase in intensity and frequency of rain events is anticipated to deliver more runoff and to increase riverine inputs to Lake Superior's ecosystem. The effects of these changes on key biogeochemical parameters were analyzed by coupling satellite data, water column sensor profiles, and discrete surface-water sampling after two "500-year" flood events in the Lake Superior basin. This study provides both a spatial and a temporal sense of how plumes interacted within the ecosystem. We also determined the significant differences in water quality parameters for plume versus non-plume waters. These two plumes were important for delivery of nutrients, with variable transport of sediments and colored dissolved organic matter (CDOM). Data from the 2012 storm event showed a significant input of total nitrogen (TN), total phosphorous (TP) and CDOM to the system. In the 2016 storm event, carbon cycling parameters (acidity, total inorganic carbon (TIC), and dissolved organic carbon (DOC), and ammonia levels were elevated within the plume. In neither storm event was there a significant difference in chlorophyll a between plume and non-plume waters during our sampling cruises. These two plume events were similar in amount of precipitation, but their effect on the biogeochemistry of Lake Superior varied due to differences in the watersheds where the rain fell. The studied plume events were dynamic, changing with currents, winds and the settling of suspended sediments.
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Affiliation(s)
- Ellen M Cooney
- Water Resources Science Program, University of Minnesota, 2205 East 5 St, Duluth, MN 55812.
| | - Paul McKinney
- Large Lakes Observatory, University of Minnesota Duluth, 2205 East 5 St. Duluth, MN 55812.
- US EPA Mid-Continent Ecology, 6201 Congdon Blvd. Duluth MN 55804
| | - Robert Sterner
- Large Lakes Observatory and Department of Biology, University of Minnesota, 2205 East 5 St. Duluth, MN 55812.
| | - Gaston E Small
- Biology, University of St. Thomas, 2115 Summit Ave, St. Paul, MN 55105.
| | - Elizabeth C Minor
- Large Lakes Observatory and Department of Chemistry and Biochemistry University of Minnesota, 2205 East 5 St. Duluth, MN 55812.
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Pelagic barite precipitation at micromolar ambient sulfate. Nat Commun 2017; 8:1342. [PMID: 29109481 PMCID: PMC5673900 DOI: 10.1038/s41467-017-01229-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 08/31/2017] [Indexed: 11/08/2022] Open
Abstract
Geochemical analyses of sedimentary barites (barium sulfates) in the geological record have yielded fundamental insights into the chemistry of the Archean environment and evolutionary origin of microbial metabolisms. However, the question of how barites were able to precipitate from a contemporary ocean that contained only trace amounts of sulfate remains controversial. Here we report dissolved and particulate multi-element and barium-isotopic data from Lake Superior that evidence pelagic barite precipitation at micromolar ambient sulfate. These pelagic barites likely precipitate within particle-associated microenvironments supplied with additional barium and sulfate ions derived from heterotrophic remineralization of organic matter. If active during the Archean, pelagic precipitation and subsequent sedimentation may account for the genesis of enigmatic barite deposits. Indeed, barium-isotopic analyses of barites from the Paleoarchean Dresser Formation are consistent with a pelagic mechanism of precipitation, which altogether offers a new paradigm for interpreting the temporal occurrence of barites in the geological record.
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Lee Y, Lee B, Hur J, Min JO, Ha SY, Ra K, Kim KT, Shin KH. Biodegradability of algal-derived organic matter in a large artificial lake by using stable isotope tracers. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:8358-8366. [PMID: 26780057 DOI: 10.1007/s11356-016-6046-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/04/2016] [Indexed: 06/05/2023]
Abstract
In order to understand the biodegradability of algal-derived organic matter, biodegradation experiments were conducted with (13)C and (15)N-labeled natural phytoplankton and periphytic algal populations in experimental conditions for 60 days. Qualitative changes in the dissolved organic matter were also determined using parallel factor analysis and the stable carbon isotopic composition of the hydrophobic dissolved organic matter through the experimental period. Although algal-derived organic matter is considered to be easily biodegradable, the initial amounts of total organic carbon newly produced by phytoplankton and periphytic algae remained approximately 16 and 44 % after 60 days, respectively, and about 22 and 43 % of newly produced particulate nitrogen remained. Further, the dissolved organic carbon derived from both algal populations increased significantly after 60 days. Although the dissolved organic matter gradually became refractory, the contributions of the algal-derived organic matter to the dissolved organic matter and hydrophobic dissolved organic matter increased. Our laboratory experimental results suggest that algal-derived organic matter produced by phytoplankton and periphytic algae could contribute significantly to the non-biodegradable organic matter through microbial transformations.
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Affiliation(s)
- Yeonjung Lee
- Department of Marine Sciences and Convergent Technology, Hanyang University, Ansan, 15588, Republic of Korea
| | - Bomi Lee
- Department of Environment and Energy, Sejong University, Seoul, 05006, Republic of Korea
| | - Jin Hur
- Department of Environment and Energy, Sejong University, Seoul, 05006, Republic of Korea
| | - Jun-Oh Min
- Division of Polar Ocean Environment Research, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Sun-Yong Ha
- Division of Polar Ocean Environment Research, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Kongtae Ra
- Marine Environment and Conservation Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea
| | - Kyung-Tae Kim
- Marine Environment and Conservation Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea
| | - Kyung-Hoon Shin
- Department of Marine Sciences and Convergent Technology, Hanyang University, Ansan, 15588, Republic of Korea.
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7
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Li H, Minor EC. Dissolved organic matter in Lake Superior: insights into the effects of extraction methods on chemical composition. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2015; 17:1829-1840. [PMID: 26350791 DOI: 10.1039/c5em00199d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Dissolved organic matter (DOM) in aquatic systems plays many biogeochemical roles, acting as a sunscreen, a food source, a trace metal chelator, and a photosensitizer. The efficiency of DOM in these roles is, in part, a function of its composition, which is difficult to determine due to its heterogeneity and the difficulty in isolating representative portions for subsequent molecular level analyses. In this study, the performance of two major types of solid phase extraction (SPE) resins (C18 vs. polymeric SDVB) in disk format (C18 disk vs. SDB-XC disk) was studied using DOM from Lake Superior, the earth's largest lake by area. The performance of the two SPE disks and their influences on the molecular chemical composition of the extracted retentates were studied with UV-vis spectrometry and negative-ion electrospray Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). We found that SDB-XC disks outperformed C18 disks in the isolation of DOM in terms of both higher recovery and less fractionation relative to the initial DOM composition. Extracts of the same samples obtained with the different resins shared 70% of molecular formulae. Compounds exclusive to the SDB-XC extractions exhibited similar compound distributions to those of the shared formulae but were enriched in N, P, and S and more aromatic. The C18 exclusive compounds had somewhat higher H/C ratios and contained a large proportion of compounds with oxygen and nitrogen (CHON). Cluster analysis and principle component analysis confirmed that sample location was the main driver of the composition of extracted samples but showed some fractionation of the samples based upon the type of resin.
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Affiliation(s)
- Hongyu Li
- Large Lakes Observatory and Water Resources Science Program, University of Minnesota, Duluth, MN 55812, USA
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Weinke AD, Kendall ST, Kroll DJ, Strickler EA, Weinert ME, Holcomb TM, Defore AA, Dila DK, Snider MJ, Gereaux LC, Biddanda BA. Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone. JOURNAL OF PLANKTON RESEARCH 2014; 36:1528-1542. [PMID: 25954055 PMCID: PMC4226232 DOI: 10.1093/plankt/fbu066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 06/30/2014] [Indexed: 06/04/2023]
Abstract
During the summers of 2002-2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L-1 day-1, respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and -33 ± 15 µg C L-1day-1, respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles.
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Affiliation(s)
- Anthony D. Weinke
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
| | - Scott T. Kendall
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
| | - Daniel J. Kroll
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
- Munson Medical Center, 1105 6th Street, Traverse City, MI 49684, USA
| | - Eric A. Strickler
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
- Salish Sea Expeditions, 647 Horizon View Pl Nw, Bainbridge Isle, WA 98110, USA
| | - Maggie E. Weinert
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
| | - Thomas M. Holcomb
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
- Herman Miller, 855 East Main Street, Mail Stop 0156, Zeeland, MI 49464, USA
| | - Angela A. Defore
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
- USC Baruch Marine Field Lab, U. South Carolina, Po Box 1630, Georgetown, SC 29442, USA
| | - Deborah K. Dila
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
- School of Freshwater Sciences, U. Wisconsin-Milwaukee, 600 E. Greenfield Ave, Milwaukee, WI 53204, USA
| | - Michael J. Snider
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
| | - Leon C. Gereaux
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
| | - Bopaiah A. Biddanda
- Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI 49441, USA
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Bennington V, McKinley GA, Urban NR, McDonald CP. Can spatial heterogeneity explain the perceived imbalance in Lake Superior's carbon budget? A model study. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jg001895] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Peterson BM, McNally AM, Cory RM, Thoemke JD, Cotner JB, McNeill K. Spatial and temporal distribution of singlet oxygen in Lake Superior. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:7222-9. [PMID: 22703113 DOI: 10.1021/es301105e] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A multiyear field study was undertaken on Lake Superior to investigate singlet oxygen ((1)O(2)) photoproduction. Specifically, trends within the lake were examined, along with an assessment of whether correlations existed between chromophoric dissolved organic matter (CDOM) characteristics and (1)O(2) production rates and quantum yields. Quantum yield values were determined and used to estimate noontime surface (1)O(2) steady-state concentrations ([(1)O(2)](ss)). Samples were subdivided into three categories based on their absorbance properties (a300): riverine, river-impacted, or open lake sites. Using calculated surface [(1)O(2)](ss), photochemical half-lives under continuous summer sunlight were calculated for cimetidine, a pharmaceutical whose reaction with (1)O(2) has been established, to be on the order of hours, days, and a week for the riverine, river-impacted, and open lake waters, respectively. Of the CDOM properties investigated, it was found that dissolved organic carbon (DOC) and a300 were the best parameters for predicting production rates of [(1)O(2)](ss). For example, given the correlations found, one could predict [(1)O(2)](ss) within a factor of 4 using a300 alone. Changes in the quantum efficiency of (1)O(2) production upon dilution of river water samples with lake water samples demonstrated that the CDOM found in the open lake is not simply diluted riverine organic matter. The open lake pool was characterized by low absorption coefficient, low fluorescence, and low DOC, but more highly efficient (1)O(2) production and predominates the Lake Superior system spatially. This study establishes that parameters that reflect the quantity of CDOM (e.g., a300 and DOC) correlate with (1)O(2) production rates, while parameters that characterize the absorbance spectrum (e.g., spectral slope coefficient and E2:E3) correlate with (1)O(2) production quantum yields.
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Affiliation(s)
- Britt M Peterson
- Department of Chemistry, University of Minnesota , Minneapolis, Minnesota, United States
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12
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Bennington V, McKinley GA, Kimura N, Wu CH. General circulation of Lake Superior: Mean, variability, and trends from 1979 to 2006. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jc006261] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Kumar S, Sterner RW, Finlay JC. Nitrogen and carbon uptake dynamics in Lake Superior. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jg000720] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sanjeev Kumar
- Department of Ecology, Evolution, and Behavior; University of Minnesota; St. Paul Minnesota USA
| | - Robert W. Sterner
- Department of Ecology, Evolution, and Behavior; University of Minnesota; St. Paul Minnesota USA
| | - Jacques C. Finlay
- Department of Ecology, Evolution, and Behavior; University of Minnesota; St. Paul Minnesota USA
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Finlay JC, Sterner RW, Kumar S. Isotopic evidence for in-lake production of accumulating nitrate in Lake Superior. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2007; 17:2323-2332. [PMID: 18213972 DOI: 10.1890/07-0245.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A century-long increase in nitrate (NO3-) in the water column of Lake Superior is a classic example of recent nitrogen accumulation in ecosystems, but its cause and relationship to historical NO3- deposition is unknown. We used stable isotope ratios of oxygen and nitrogen in nitrate (delta18O-NO3 and delta15N-NO3) to examine its sources in this large lake, which represents 10% of the world's surficial liquid freshwater. The most parsimonious hypothesis to explain the rise in NO3- is that the lake is accruing NO3- deposited directly on the lake surface because it is too unproductive to completely assimilate all of it. Data for delta18O-NO3 in external sources and the water column, however, are inconsistent with this hypothesis. Instead, the isotopic evidence indicates strongly that the accumulating NO3- is almost entirely derived from nitrification occurring within the lake. While increases in atmospheric deposition of NO3- may have played a role in its buildup in the lake, other factors such as increases in NH4+ and dissolved organic nitrogen inputs from precipitation or rivers, increases in nitrogen fluxes from the sediments, and decreases in burial rates must also be considered as potential drivers of rising NO3-. The sustained accumulation of nitrogen in Lake Superior is thus more complex and incompletely understood than previously assumed.
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Affiliation(s)
- Jacques C Finlay
- Department of Ecology, Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota 55108, USA.
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