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764 results on '"Leavitt, Peter R."'

151. A 500-year context for the recent surge in sockeye salmon (Oncorhynchus nerka) abundance in the Alagnak River, Alaska

Author

Schindler, Daniel E., Leavitt, Peter R., Johnson, Susan P., and Brock, Curtis S.

Subjects
Alaska -- Natural resources, Sockeye salmon -- Research, Sockeye salmon -- Demographic aspects, Earth sciences
Abstract

Abstract: Returns of sockeye salmon (Oncorhynchus nerka) to the Alagnak River in Bristol Bay, Alaska, during the last 3 years were unprecedented in the last five decades. Enumerated run sizes [...]

Published
2006

153. Abrupt changes in the physical and biological structure of endorheic upland lakes due to 8‐m lake‐level variation during the 20th century.

Author

Bjorndahl, Judith A., Gushulak, Cale A.C., Mezzini, Stefano, Simpson, Gavin L., Haig, Heather A., Leavitt, Peter R., and Finlay, Kerri

Subjects
ENDORHEIC lakes, MORPHOLOGY, ANOXIC zones, SULFUR bacteria, EUPHOTIC zone
Abstract

Climate‐induced variation in lake level can affect physicochemical properties of endorheic lakes, but its consequences for phototrophic production and regime shifts are not well understood. Here, we quantified changes in the abundance and community composition of phototrophs in Kenosee and White Bear lakes, two endorheic basins in the parkland Moose Mountain uplands of southeastern Saskatchewan, Canada, which have experienced > 8 m declines in water level since ~ 1900. We hypothesized that lower water levels and warmer temperatures should manifest as increased abundance of phytoplankton, particularly cyanobacteria, and possibly trigger a regime shift to turbid conditions due to evaporative concentration of nutrients and solutes. High‐resolution analysis of sedimentary pigments revealed an increase in total phototrophic abundance (as β‐carotene) concurrent with lake‐level decline beginning ~ 1930, but demonstrated little directional change in cyanobacteria. Instead, significant increases in obligately anaerobic purple sulfur bacteria (as okenone) occurred in both lakes during ~ 1930–1950, coeval with alterations to light environments and declines in lake level. The presence of okenone suggests that climate‐induced increases in solute concentrations may have favored the formation of novel bacterial habitats where photic and anoxic zones overlapped. Generalized additive models showed that establishment of this unique habitat was likely preceded by increased temporal variance of sulfur bacteria, but not phytoplankton or cyanobacteria, suggesting that this abrupt change to physical lake structure was unique to deep‐water environments. Such climate‐induced shifts may become more frequent in the region due to hydrological stress on lake levels due to warming temperatures across the Northern Great Plains. [ABSTRACT FROM AUTHOR]

Published
2022
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155. Ecological dynamics of a peri-urban lake: a multi-proxy paleolimnological study of Cultus Lake (British Columbia) over the past ~ 200 years

Author

Gauthier, Joanna, primary, Gregory-Eaves, Irene, additional, Bunting, Lynda, additional, Leavitt, Peter R., additional, Tran, Tanya, additional, Godbout, Lyse, additional, Finney, Bruce P., additional, Schindler, Daniel E., additional, Chen, Guangjie, additional, Holtgrieve, Gordon, additional, Shapley, Mark, additional, and Selbie, Daniel T., additional

Published
2020
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162. Contributors

Author

BAIRD, DONALD J., primary, BATES, DAVID J., additional, BAXTER, COLDEN V., additional, BENFIELD, E.F., additional, BENKE, ARTHUR C., additional, BERNOT, MELODY J., additional, BISSON, PETER A., additional, BOTT, THOMAS L., additional, BOWDEN, WILLIAM B., additional, BUFFINGTON, JOHN M., additional, CARTER, JAMES L., additional, CRENSHAW, CHELSEA L., additional, CULP, JOSEPH M., additional, CUMMINS, KENNETH W., additional, DAHM, CLIFFORD N., additional, FEMINELLA, JACK W., additional, FINDLAY, STUART, additional, FORTINO, KENNETH, additional, GELWICK, FRANCES P., additional, GLIME, JANICE M., additional, GORE, JAMES A., additional, GREGORY, STANLEY V., additional, GRIMM, NANCY B., additional, GRUBAUGH, JACK W., additional, GULIS, VLADISLAV, additional, HANNAFORD, MORGAN J., additional, HAUER, F. RICHARD, additional, HERSHEY, ANNE E., additional, HILL, WALTER R., additional, HURYN, ALEXANDER D., additional, HUTCHENS, JOHN J., additional, LALIBERTE, GINA D., additional, LAMBERTI, GARY A., additional, LEAVITT, PETER R., additional, LI, HIRAM W., additional, LI, JUDITH L., additional, LORANG, MARK S., additional, LOWE, REX L., additional, MATTHEWS, WILLIAM J., additional, MERRITT, RICHARD W., additional, MINSHALL, G. WAYNE, additional, MONTGOMERY, DAVID R., additional, MULHOLLAND, PATRICK J., additional, MYERS, MARILYN J., additional, NEWBURY, ROBERT W., additional, PALMER, MARGARET A., additional, PECKARSKY, BARBARA L., additional, PETERSON, BRUCE J., additional, PRINGLE, CATHERINE M., additional, RESH, VINCENT H., additional, RIIS, TENNA, additional, ROLLINS, SCOTT L., additional, ROSI-MARSHALL, EMMA J., additional, RUGENSKI, AMANDA, additional, RUNDLE, SIMON D., additional, SMOCK, LEONARD A., additional, STANFORD, JACK A., additional, STEINMAN, ALAN D., additional, STEVENSON, R. JAN, additional, STRAYER, DAVID L., additional, SUBERKROPP, KELLER F., additional, TANK, JENNIFER L., additional, TRISKA, FRANK J., additional, ULSETH, AMBER J., additional, VALETT, H. MAURICE, additional, WALLACE, J. BRUCE, additional, WARD, AMELIA K., additional, WEBSTER, JACKSON R., additional, and WOESSNER, WILLIAM W., additional

Published
2007
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163. Marked blue discoloration of late winter ice and water due to autumn blooms of cyanobacteria.

Author

Haig, Heather A., Chegoonian, Amir M., Davies, John-Mark, Bateson, Deirdre, and Leavitt, Peter R.

Abstract

Haig HA, Chegoonian AM, Davies J-M, Bateson D, Leavitt PR. 2021. Marked blue discoloration of late winter ice and water due to autumn blooms of cyanobacteria. Lake Reserv Manage. 38:1–15. Continued eutrophication of inland waters by nutrient pollution can combine with unprecedented atmospheric and lake warming to create emergent environmental surprises. Here we report the first known occurrence of marked blue discoloration of ice and water in highly eutrophic prairie lakes during late winter 2021. Intense blue staining was reported first to governmental agencies by ice fishers in early March 2021, then communicated widely through social media, resulting in First Nations and public concern over potential septic field release, toxic spills, urban pollution, and agricultural mismanagement. Analysis of water from stained and reference sites using ultraviolet (UV)–visible spectrophotometry and high-performance liquid chromatography demonstrated that the blue color arose from high concentrations (∼14 mg/L) of the cyanobacterial pigment C-phycocyanin that was released after an unexpected bloom of Aphanizomenon flos-aquae in late October 2020 was frozen into littoral ice. Remote sensing using the Sentinel 3 A/B OLCI and Sentinel 2 A/B MSI satellite platforms suggested that blue staining encompassed 0.68 ± 0.24 km2 (4.25 ± 1.5% of lake surface area), persisted over 4 weeks, and was located within 50 m of the lakeshore in regions where fall blooms of cyanobacteria had been particularly dense. Although toxin levels were low (∼0.2 μg microcystin/L), high concentrations of C-phycocyanin raised public concern over eutrophication, pollution, and climate change, and resulted in rapid governmental and academic response. Given that climate change and nutrient pollution are increasing the magnitude and duration of cyanobacterial blooms, blue staining of lake ice may become widespread in eutrophic lakes subject to ice cover. [ABSTRACT FROM AUTHOR]

Published
2022
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165. Next generation sequencing to identify lacustrine haptophytes in the Canadian Prairies: significance for temperature proxy applications

Author

Plancq, Julien, Couto, Jillian, Ijaz, Umer Zeeshan, Leavitt, Peter R., and Toney, Jaime

Abstract

The Great Plains of North America often experience prolonged droughts that have major economic and environmental impacts. Temperature reconstructions are thus crucial to help decipher the mechanisms responsible for drought occurrences. Long-chain alkenones (LCAs), lipids produced by three major phylogenetic groups (Group I, II and III) of haptophyte algae within the order Isochrysidales, are increasingly used for temperature reconstructions in lacustrine settings. However, to select the most appropriate calibration of the LCA-based temperature proxy, it is first essential to identify the LCA-producing haptophyte species present. Here we used next generation sequencing to target the 18S rRNA haptophyte gene from sediments with distinct LCA profiles to identify the LCA-producer(s) from five Canadian prairie lakes. In total, 374 operational taxonomic units (OTUs) were identified across the studied samples, of which 234 fell within the Phylum Haptophyta. Among the most abundant OTUs, three were characterized as LCA-producers, one falling within the Group I haptophytes and two within the Group II haptophytes. The OTU from Group I haptophytes was associated with a single, highly-specific LCA profile, whereas Group II OTUs showed higher variability in LCA distributions. Our study revealed that most of the LCA-producing OTUs thriving in the Canadian lakes are included within the genus Isochrysis, which helps guide selection of the most appropriate calibration for down-core temperature reconstructions. Our findings also suggest that the temperature dependency is likely consistent within different taxa from Group I and Group II haptophytes, but that other environmental parameters may influence the accuracy of the calibration.

Published
2019

166. Science Advances

Author

Tiegs, Scott D., Costello, David M., Isken, Mark W., Woodward, Guy, McIntyre, Peter B., Gessner, Mark O., Chauvet, Eric, Griffiths, Natalie A., Flecker, Alex S., Acuña, Vicenç, Albariño, Ricardo, Allen, Daniel C., Alonso, Cecilia, Andino, Patricio, Arango, Clay, Aroviita, Jukka, Barbosa, Marcus V. M., Barmuta, Leon A., Baxter, Colden V., Bell, Thomas D. C., Bellinger, Brent, Boyero, Luz, Brown, Lee E., Bruder, Andreas, Bruesewitz, Denise A., Burdon, Francis J., Callisto, Marcos, Canhoto, Cristina, Capps, Krista A., Castillo, María M., Clapcott, Joanne, Colas, Fanny, Colón-Gaud, Checo, Cornut, Julien, Crespo-Pérez, Verónica, Cross, Wyatt F., Culp, Joseph M., Danger, Michael, Dangles, Olivier, de Eyto, Elvira, Derry, Alison M., Villanueva, Veronica Díaz, Douglas, Michael M., Elosegi, Arturo, Encalada, Andrea C., Entrekin, Sally, Espinosa, Rodrigo, Ethaiya, Diana, Ferreira, Verónica, Ferriol, Carmen, Flanagan, Kyla M., Fleituch, Tadeusz, Follstad Shah, Jennifer J., Frainer, André, Friberg, Nikolai, Frost, Paul C., Garcia, Erica A., García Lago, Liliana, García Soto, Pavel Ernesto, Ghate, Sudeep, Giling, Darren P., Gilmer, Alan, Gonçalves, José Francisco, Gonzales, Rosario Karina, Graça, Manuel A. S., Grace, Mike, Grossart, Hans-Peter, Guérold, François, Gulis, Vlad, Hepp, Luiz U., Higgins, Scott, Hishi, Takuo, Huddart, Joseph, Hudson, John, Imberger, Samantha, Iñiguez-Armijos, Carlos, Iwata, Tomoya, Janetski, David J., Jennings, Eleanor, Kirkwood, Andrea E., Koning, Aaron A., Kosten, Sarian, Kuehn, Kevin A., Laudon, Hjalmar, Leavitt, Peter R., Lemes da Silva, Aurea L., Leroux, Shawn J., LeRoy, Carri J., Lisi, Peter J., MacKenzie, Richard, Marcarelli, Amy M., Masese, Frank O., McKie, Brendan G., Oliveira Medeiros, Adriana, Meissner, Kristian, Miliša, Marko, Mishra, Shailendra, Miyake, Yo, Moerke, Ashley, Mombrikotb, Shorok, Mooney, Rob, Moulton, Tim, Muotka, Timo, Negishi, Junjiro N., Neres-Lima, Vinicius, Nieminen, Mika L., Nimptsch, Jorge, Ondruch, Jakub, Paavola, Riku, Pardo, Isabel, Patrick, Christopher J., Peeters, Edwin T. H. M., Pozo, Jesus, Pringle, Catherine, Prussian, Aaron, Quenta, Estefania, Quesada, Antonio, Reid, Brian, Richardson, John S., Rigosi, Anna, Rincón, José, Rîşnoveanu, Geta, Robinson, Christopher T., Rodríguez-Gallego, Lorena, Royer, Todd V., Rusak, James A., Santamans, Anna C., Selmeczy, Géza B., Simiyu, Gelas, Skuja, Agnija, Smykla, Jerzy, Sridhar, Kandikere R., Sponseller, Ryan, Stoler, Aaron, Swan, Christopher M., Szlag, David, Teixeira-de Mello, Franco, Tonkin, Jonathan D., Uusheimo, Sari, Veach, Allison M., Vilbaste, Sirje, Vought, Lena B. M., Wang, Chiao-Ping, Webster, Jackson R., Wilson, Paul B., Woelfl, Stefan, Xenopoulos, Marguerite A., Yates, Adam G., Yoshimura, Chihiro, Yule, Catherine M., Zhang, Yixin X., Zwart, Jacob A., School of Biological and Chemical Sciences, Queen Mary University of London (QMUL), Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB), Leibniz Association, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, ICRA, Catalan Institute for Water Research, ICRA, Pontificia Universidad Catolica del Ecuador, Wetland ecology department (Seville, Espagne), Doñana biological station - CSIC (SPAIN), Swiss Federal Institute of Aquatic Science and Technology - EAWAG (SWITZERLAND), Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences – Uppsala, Sweden, Burdon, Universidade Federal de Minas Gerais [Belo Horizonte] (UFMG), Marine and environmental research centre - IMAR-CMA (Coimbra, Portugal), University of Coimbra [Portugal] (UC), GRET, Sécurité et Qualité des Produits d'Origine Végétale (SQPOV), Institut National de la Recherche Agronomique (INRA)-Avignon Université (AU), Laboratorio de Limnología [Bariloche], Instituto Nacional de Investigaciones en Biodiversidad y Medioambiente [Bariloche] (INIBIOMA-CONICET), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional del Comahue [Neuquén] (UNCOMA)-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional del Comahue [Neuquén] (UNCOMA), Faculty of Science and Technology, University of the Basque Country, Polska Akademia Nauk (PAN), Norwegian Institute for Water Research (NIVA), Limnology of Stratified Lakes, IGB-Neuglobsow, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Faculty of Agriculture, Kyushu University, University of Bath [Bath], Yamanashi University, Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), University of Vienna [Vienna], University of Zagreb, VTT Information technology, Technical Research Centre of Finland, Instituto de Ciencias Marinas y Limnológicas, Universidate de Vigo, Hospital Universitario La Paz, Department of Biology, Universidad Autonoma de Madrid (UAM), Universidad del Zulia (LUZ), Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen, Germany, University of Southampton, Research Institute of New-Type Urbanization, Avignon Université (AU)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Oakland University (USA), Kent State University, Imperial College London, Cornell University, Department of Ecology and Evolutionary Biology, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Climate Change Science Institute [Oak Ridge] (CCSI), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Instituto Catalán de Investigación del Agua - ICRA (SPAIN) (ICRA), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional del Comahue [Neuquén] (UNCOMA), DEPARTMENT OF BIOLOGY UNIVERSITY OF OKLAHOMA NORMAN USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), University of the Republic of Uruguay, Central Washington University, Finnish Environment Institute (SYKE), Federal University of Tocantins, University of Tasmania [Hobart, Australia] (UTAS), Idaho State University, Watershed Protection Department, Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), School of Geography, University of Leeds, Leeds, UK, Swiss Federal Insitute of Aquatic Science and Technology [Dübendorf] (EAWAG), Colby College, Department of Aquatic Sciences and Assessment, University of Georgia [USA], EI Colegio de la Frontera Sur (ECOSUR), Consejo Nacional de Ciencia y Tecnología [Mexico] (CONACYT), Cawthron Institute, Risques, Ecosystèmes, Vulnérabilité, Environnement, Résilience (RECOVER), Aix Marseille Université (AMU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Georgia Southern University, University System of Georgia (USG), Pontifical Catholic University of Ecuador, Montana State University (MSU), Wilfrid Laurier University (WLU), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Universidade de Vigo, Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Department of Ecology and Evolutionary Biology [CALS], College of Agriculture and Life Sciences [Cornell University] (CALS), Cornell University [New York]-Cornell University [New York], Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Pontificia Universidad Católica del Ecuador, Universidade Federal do Tocantins (UFT), University of Leeds, Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Universidad Autónoma de Madrid (UAM), and Entomology

Subjects
Aquatic Ecology and Water Quality Management, riparian zones, ORGANIC-MATTER DECOMPOSITION, Biodiversité et Ecologie, Oceanografi, hydrologi och vattenresurser, Carbon Cycle, CARBON, ekosysteemit, Oceanography, Hydrology and Water Resources, biomes, biomit, ddc:570, carbon cycle, Humans, STREAMS, Life Science, Human Activities, Riparian zones, TEMPERATURE, Institut für Biochemie und Biologie, Ecosystem, ComputingMilieux_MISCELLANEOUS, SDG 15 - Life on Land, aquatic ecosystems, Science & Technology, WIMEK, hiilen kierto, vesiekosysteemit, Aquatic Ecology, Aquatische Ecologie en Waterkwaliteitsbeheer, rivers, Multidisciplinary Sciences, ekosysteemit (ekologia), Biomonitoring, articles, Science & Technology - Other Topics, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ecosystems, joet, Environmental Monitoring
Abstract

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale. This research was supported by awards to S.D.T. from the Ecuadorian Ministry of Science [Secretaría de Educación Superior Ciencia, Tecnología e Innovación (SENESCYT)] through the PROMETEO scholar exchange program, the Oakland University Research Development Grant program, and a Huron Mountain Wildlife Foundation research grant. N.A.G. was supported by the U.S. Department of Energy’s Office of Science, Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. We are grateful for open-access-publishing funds from Kresge Library at Oakland University and Queen’s University Belfast. This research was supported by awards to S.D.T. from the Ecuadorian Ministry of Science [Secretaría de Educación Superior Ciencia, Tecnología e Innovación (SENESCYT)] through the PROMETEO scholar exchange program, the Oakland University Research Development Grant program, and a Huron Mountain Wildlife Foundation research grant. N.A.G. was supported by the U.S. Department of Energy’s Office of Science, Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. We are grateful for open-access-publishing funds from Kresge Library at Oakland University and Queen’s University Belfast.

Published
2019
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167. SFigure_3_Pollen_Concentration – Supplemental material for Complex responses of phototrophic communities to climate warming during the Holocene of northeastern Ontario, Canada

Author

Elmslie, Brett G, Gushulak, Cale AC, Boreux, Maxime P, Lamoureux, Scott F, Leavitt, Peter R, and Cumming, Brian F

Subjects
History, Geography
Abstract

Supplemental material, SFigure_3_Pollen_Concentration for Complex responses of phototrophic communities to climate warming during the Holocene of northeastern Ontario, Canada by Brett G Elmslie, Cale AC Gushulak, Maxime P Boreux, Scott F Lamoureux, Peter R Leavitt and Brian F Cumming in The Holocene

Published
2019
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168. Global patterns and drivers of ecosystem functioning in rivers and riparian zones

Author

Tiegs, Scott D., Costello, David M., Isken, Mark W., Woodward, Guy, McIntyre, Peter B., Gessner, Mark O., Chauvet, Eric, Flecker, Alex S., Acuña, Vicenç, Albariño, Ricardo J., Allen, Daniel C., Alonso, Cecilia, Andino, Patricio, Arango, Clay P., Aroviita, Jukka, Barbosa, Marcus V. M., Barmuta, Leon A., Baxter, Colden V., Bell, Thomas D. C., Bellinger, Brent J., Boyero, Luz, Brown, Lee E., Bruder, Andreas, Bruesewitz, Denise A., Burdon, Francis J., Callisto, Marcos, Canhoto, Cristina, Capps, Krista A., Castillo, María M., Clapcott, Joanne, Colas, Fanny, Colón-Gaud, Checo, Cornut, Julien, Crespo-Pérez, Verónica, Cross, Wyatt F., Culp, Joseph M., Danger, Michael, Dangles, Olivier, de Eyto, Elvira, Derry, Alison M., Díaz Villanueva, Veronica, Douglas, Michael M., Elosegi, Arturo, Encalada, Andrea C., Entrekin, Sally, Espinosa, Rodrigo, Ethaiya, Diana, Ferreira, Verónica, Ferriol, Carmen, Flanagan, Kyla M., Fleituch, Tadeusz, Shah, Jennifer J. Follstad, Frainer, André, Friberg, Nikolai, Frost, Paul C., Garcia, Erica A., García Lago, Liliana, García Soto, Pavel Ernesto, Ghate, sudeep, Giling, Darren P., Gilmer, Alan, Gonçalves Jr., José Francisco, Gonzales, Rosario Karina, Graça, Manuel A. S., Grace, Mike, Grossart, Hans-Peter, Guérold, François, Gulis, Vlad, Hepp, Luiz U., Higgins, Scott, Hishi, Takuo, Huddart, Joseph, Hudson, John, Imberger, Samantha, Iñiguez-Armijos, Carlos, Iwata, Tomoya, Janetski, David J., Jennings, Eleanor, Kirkwood, Andrea E., Koning, Aaron A., Kosten, Sarian, Kuehn, Kevin A., Laudon, Hjalmar, Leavitt, Peter R., da Silva, Lemes, Leroux, Shawn J., LeRoy, Peter J. Lisi, MacKenzie, Richard, Marcarelli, Amy M., Masese, Frank O., McKie, Brendan G., Medeiros, Adriana Oliveira, Meissner, Kristian, Miliša, Marko, Mishra, Shailendra, Miyake, Yo, Moerke, Ashley, Mombrikotb, Shorok, mooney, Rob, Moulton, Tim, Muotka, Timo, Negishi, Junjiro N., Neres-Lima, Vinicius, Nieminen, Mika L., Nimptsch, Jorge, Ondruch, Jakub, Paavola, Riku, Pardo, Isabel, Patrick, Christopher J., Peeters, Edwin T.H.M., Pozo, Jesus, Pringle, Catherine, Prussian, Aaron, Quenta, Estefania, Quesada, Antonio, Reid, Brian, Richardson, John S., Rigosi, Anna, Rincón, José, Rîşnoveanu, Geta, Robinson, Christopher T., Rodríguez-Gallego, Lorena, Royer, Todd V., Rusak, James A., Santamans, Anna C., Selmeczy, Géza B., Simiyu, Gelas, Skuja, Agnija, Smykla, Jerzy, Sridar, Kandikere R., Sponseller, Ryan, Stoler, Aaron, Swan, Christopher M., Szlag, David, Teixeira-de Mello, Franco, Tonkin, Jonathan D., Uusheimo, Sari, Veach, Allison M., Vilbaste, Sirje, Vought, Lena B.M., Wang, Chiao-Ping, Webster, Jackson R., Wilson, Paul B., Woelfl, Stefan, Xenopoulos, Marguerite A., Yates, Adam G., Yoshimura, Chihiro, Yule, Catherine M., Zhang, Yixin X., and Zwart, Jacob A.

Subjects
VDP::Matematikk og naturvitenskap: 400::Zoologiske og botaniske fag: 480, VDP::Mathematics and natural scienses: 400::Zoology and botany: 480
Abstract

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.

Published
2019

174. Global patterns and drivers of ecosystem functioning in rivers and riparian zones

Author

Entomology, Tiegs, Scott D., Costello, David M., Isken, Mark W., Woodward, Guy, McIntyre, Peter B., Gessner, Mark O., Chauvet, Eric, Griffiths, Natalie A., Flecker, Alex S., Acuna, Vicenc, Albarino, Ricardo, Allen, Daniel C., Alonso, Cecilia, Andino, Patricio, Arango, Clay, Aroviita, Jukka, Barbosa, Marcus V. M., Barmuta, Leon A., Baxter, Colden V., Bell, Thomas D. C., Bellinger, Brent, Boyero, Luz, Brown, Lee E., Bruder, Andreas, Bruesewitz, Denise A., Burdon, Francis J., Callisto, Marcos, Canhoto, Cristina, Capps, Krista A., Castillo, Maria M., Clapcott, Joanne, Colas, Fanny, Colon-Gaud, Checo, Cornut, Julien, Crespo-Perez, Veronica, Cross, Wyatt F., Culp, Joseph M., Danger, Michael, Dangles, Olivier, de Eyto, Elvira, Derry, Alison M., Diaz Villanueva, Veronica, Douglas, Michael M., Elosegi, Arturo, Encalada, Andrea C., Entrekin, Sally A., Espinosa, Rodrigo, Ethaiya, Diana, Ferreira, Veronica, Ferriol, Carmen, Flanagan, Kyla M., Fleituch, Tadeusz, Shah, Jennifer J. Follstad, Frainer, Andre, Friberg, Nikolai, Frost, Paul C., Garcia, Erica A., Lago, Liliana Garcia, Garcia Soto, Pavel Ernesto, Ghate, Sudeep, Giling, Darren P., Gilmer, Alan, Goncalves, Jose Francisco, Jr., Gonzales, Rosario Karina, Graca, Manuel A. S., Grace, Mike, Grossart, Hans-Peter, Guerold, Francois, Gulis, Vlad, Hepp, Luiz U., Higgins, Scott, Hishi, Takuo, Huddart, Joseph, Hudson, John, Imberger, Samantha, Iniguez-Armijos, Carlos, Iwata, Tomoya, Janetski, David J., Jennings, Eleanor, Kirkwood, Andrea E., Koning, Aaron A., Kosten, Sarian, Kuehn, Kevin A., Laudon, Hjalmar, Leavitt, Peter R., Lemes da Silva, Aurea L., Leroux, Shawn J., Leroy, Carri J., Lisi, Peter J., MacKenzie, Richard, Marcarelli, Amy M., Masese, Frank O., Mckie, Brendan G., Oliveira Medeiros, Adriana, Meissner, Kristian, Milisa, Marko, Mishra, Shailendra, Miyake, Yo, Moerke, Ashley, Mombrikotb, Shorok, Mooney, Rob, Moulton, Tim, Muotka, Timo, Negishi, Junjiro N., Neres-Lima, Vinicius, Nieminen, Mika L., Nimptsch, Jorge, Ondruch, Jakub, Paavola, Riku, Pardo, Isabel, Patrick, Christopher J., Peeters, Edwin T. H. M., Pozo, Jesus, Pringle, Catherine, Prussian, Aaron, Quenta, Estefania, Quesada, Antonio, Reid, Brian, Richardson, John S., Rigosi, Anna, Rincon, Jose, Risnoveanu, Geta, Robinson, Christopher T., Rodriguez-Gallego, Lorena, Royer, Todd V., Rusak, James A., Santamans, Anna C., Selmeczy, Geza B., Simiyu, Gelas, Skuja, Agnija, Smykla, Jerzy, Sridhar, Kandikere R., Sponseller, Ryan, Stoler, Aaron, Swan, Christopher M., Szlag, David, Teixeira-de Mello, Franco, Tonkin, Jonathan D., Uusheimo, Sari, Veach, Allison M., Vilbaste, Sirje, Vought, Lena B. M., Wang, Chiao-Ping, Webster, Jackson R., Wilson, Paul B., Woelfl, Stefan, Xenopoulos, Marguerite A., Yates, Adam G., Yoshimura, Chihiro, Yule, Catherine M., Zhang, Yixin X., Zwart, Jacob A., Entomology, Tiegs, Scott D., Costello, David M., Isken, Mark W., Woodward, Guy, McIntyre, Peter B., Gessner, Mark O., Chauvet, Eric, Griffiths, Natalie A., Flecker, Alex S., Acuna, Vicenc, Albarino, Ricardo, Allen, Daniel C., Alonso, Cecilia, Andino, Patricio, Arango, Clay, Aroviita, Jukka, Barbosa, Marcus V. M., Barmuta, Leon A., Baxter, Colden V., Bell, Thomas D. C., Bellinger, Brent, Boyero, Luz, Brown, Lee E., Bruder, Andreas, Bruesewitz, Denise A., Burdon, Francis J., Callisto, Marcos, Canhoto, Cristina, Capps, Krista A., Castillo, Maria M., Clapcott, Joanne, Colas, Fanny, Colon-Gaud, Checo, Cornut, Julien, Crespo-Perez, Veronica, Cross, Wyatt F., Culp, Joseph M., Danger, Michael, Dangles, Olivier, de Eyto, Elvira, Derry, Alison M., Diaz Villanueva, Veronica, Douglas, Michael M., Elosegi, Arturo, Encalada, Andrea C., Entrekin, Sally A., Espinosa, Rodrigo, Ethaiya, Diana, Ferreira, Veronica, Ferriol, Carmen, Flanagan, Kyla M., Fleituch, Tadeusz, Shah, Jennifer J. Follstad, Frainer, Andre, Friberg, Nikolai, Frost, Paul C., Garcia, Erica A., Lago, Liliana Garcia, Garcia Soto, Pavel Ernesto, Ghate, Sudeep, Giling, Darren P., Gilmer, Alan, Goncalves, Jose Francisco, Jr., Gonzales, Rosario Karina, Graca, Manuel A. S., Grace, Mike, Grossart, Hans-Peter, Guerold, Francois, Gulis, Vlad, Hepp, Luiz U., Higgins, Scott, Hishi, Takuo, Huddart, Joseph, Hudson, John, Imberger, Samantha, Iniguez-Armijos, Carlos, Iwata, Tomoya, Janetski, David J., Jennings, Eleanor, Kirkwood, Andrea E., Koning, Aaron A., Kosten, Sarian, Kuehn, Kevin A., Laudon, Hjalmar, Leavitt, Peter R., Lemes da Silva, Aurea L., Leroux, Shawn J., Leroy, Carri J., Lisi, Peter J., MacKenzie, Richard, Marcarelli, Amy M., Masese, Frank O., Mckie, Brendan G., Oliveira Medeiros, Adriana, Meissner, Kristian, Milisa, Marko, Mishra, Shailendra, Miyake, Yo, Moerke, Ashley, Mombrikotb, Shorok, Mooney, Rob, Moulton, Tim, Muotka, Timo, Negishi, Junjiro N., Neres-Lima, Vinicius, Nieminen, Mika L., Nimptsch, Jorge, Ondruch, Jakub, Paavola, Riku, Pardo, Isabel, Patrick, Christopher J., Peeters, Edwin T. H. M., Pozo, Jesus, Pringle, Catherine, Prussian, Aaron, Quenta, Estefania, Quesada, Antonio, Reid, Brian, Richardson, John S., Rigosi, Anna, Rincon, Jose, Risnoveanu, Geta, Robinson, Christopher T., Rodriguez-Gallego, Lorena, Royer, Todd V., Rusak, James A., Santamans, Anna C., Selmeczy, Geza B., Simiyu, Gelas, Skuja, Agnija, Smykla, Jerzy, Sridhar, Kandikere R., Sponseller, Ryan, Stoler, Aaron, Swan, Christopher M., Szlag, David, Teixeira-de Mello, Franco, Tonkin, Jonathan D., Uusheimo, Sari, Veach, Allison M., Vilbaste, Sirje, Vought, Lena B. M., Wang, Chiao-Ping, Webster, Jackson R., Wilson, Paul B., Woelfl, Stefan, Xenopoulos, Marguerite A., Yates, Adam G., Yoshimura, Chihiro, Yule, Catherine M., Zhang, Yixin X., and Zwart, Jacob A.

Abstract

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.

Published
2019

176. Breathing space: deoxygenation of aquatic environments can drive differential ecological impacts across biological invasion stages.

Author

Dickey, James W. E., Coughlan, Neil E., Dick, Jaimie T. A., Médoc, Vincent, McCard, Monica, Leavitt, Peter R., Lacroix, Gérard, Fiorini, Sarah, Millot, Alexis, and Cuthbert, Ross N.

Abstract

The influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species' impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages. [ABSTRACT FROM AUTHOR]

Published
2021
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179. Spatial and temporal variation in nitrogen fixation and its importance to phytoplankton in phosphorus-rich lakes

Author

Hayes, Nicole M., Patoine, Alain, Haig, Heather A., Simpson, Gavin L., Swarbrick, Vanessa J., Wiik, Emma, and Leavitt, Peter R.

Subjects
nutrient limitation, fungi, δN, nitrogen demand, stable isotopes, Aquatic Science, cyanobacteria
Abstract

© 2018 The Authors. Freshwater Biology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. 1. Limnological theory posits that phosphorus (P) limits primary production in freshwater lakes, in part because fixation of atmospheric nitrogen (N2) can compensate for limitations in nitrogen (N) supply to phytoplankton. However, quantitative estimates of the degree to which N2 fixation satisfies planktonic N demand are rare. 2. Here we used biweekly sampling during summer in seven lakes over 2 decades to estimate both planktonic N2 fixation and phytoplankton N demand. We further assessed the ability of biologically fixed N to satisfy N needs of primary producers in productive hardwater lakes. 3. Phytoplankton N requirements, derived from estimates of phytoplankton productivity and N content, were moderately synchronous (S = 0.41) among lakes (ca. 0.1–9.2 mg N m–3 hr–1). In contrast, rates of N2 fixation determined using isotopic natural abundance method (NAM; 0.002–3.2 mg N m–3 hr–1), or heterocyte-based calculations (0.10–1.78 mg N m–3 hr–1), varied asynchronously (SNAM = –0.03 and SHeterocyte = –0.11) among basins, accounted for a median of 3.5% (mean 11.3% ± 21.6) of phytoplankton demand, and were correlated to the abundance of Nostocales cyanobacteria when analysed using generalised additive models. 4. Overall, the total mass of fixed N accounted for a median of only 3.0% of the spring standing stock of total dissolved N in study lakes (mean 7.5 ± 12.1%), with higher relative importance of fixed N in highly productive downstream lakes. Thus, while fixed N helps sustain primary productivity, particularly in years with high rates of N2-fixation, it does not appear to eliminate N limitation of phytoplankton growth in these P-rich hardwater lakes. This work was supported by the NSERC Canada Discovery Grants program, Canada Research Chairs, Canada Foundation for Innovation, the Province of Saskatchewan, the University of Regina, and Queen's University Belfast. Faculty yes

Published
2018
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186. Taxon-specific variation in δ13C and δ15N of subfossil invertebrate remains: Insights into historical trophodynamics in lake food-webs

Author

Anas, M.U. Mohamed, primary, Simpson, Gavin L., additional, Leavitt, Peter R., additional, Cumming, Brian F., additional, Laird, Kathleen R., additional, Scott, Kenneth A., additional, Das, Biplob, additional, Wolfe, Jared D., additional, Hesjedal, Brittany, additional, Mushet, Graham R., additional, Walker, Alison, additional, Meegahage, Buddhine J., additional, and Wissel, Björn, additional

Published
2019
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189. Global patterns and drivers of ecosystem functioning in rivers and riparian zones

Author

Tiegs, Scott D., primary, Costello, David M., additional, Isken, Mark W., additional, Woodward, Guy, additional, McIntyre, Peter B., additional, Gessner, Mark O., additional, Chauvet, Eric, additional, Griffiths, Natalie A., additional, Flecker, Alex S., additional, Acuña, Vicenç, additional, Albariño, Ricardo, additional, Allen, Daniel C., additional, Alonso, Cecilia, additional, Andino, Patricio, additional, Arango, Clay, additional, Aroviita, Jukka, additional, Barbosa, Marcus V. M., additional, Barmuta, Leon A., additional, Baxter, Colden V., additional, Bell, Thomas D. C., additional, Bellinger, Brent, additional, Boyero, Luz, additional, Brown, Lee E., additional, Bruder, Andreas, additional, Bruesewitz, Denise A., additional, Burdon, Francis J., additional, Callisto, Marcos, additional, Canhoto, Cristina, additional, Capps, Krista A., additional, Castillo, María M., additional, Clapcott, Joanne, additional, Colas, Fanny, additional, Colón-Gaud, Checo, additional, Cornut, Julien, additional, Crespo-Pérez, Verónica, additional, Cross, Wyatt F., additional, Culp, Joseph M., additional, Danger, Michael, additional, Dangles, Olivier, additional, de Eyto, Elvira, additional, Derry, Alison M., additional, Villanueva, Veronica Díaz, additional, Douglas, Michael M., additional, Elosegi, Arturo, additional, Encalada, Andrea C., additional, Entrekin, Sally, additional, Espinosa, Rodrigo, additional, Ethaiya, Diana, additional, Ferreira, Verónica, additional, Ferriol, Carmen, additional, Flanagan, Kyla M., additional, Fleituch, Tadeusz, additional, Follstad Shah, Jennifer J., additional, Frainer, André, additional, Friberg, Nikolai, additional, Frost, Paul C., additional, Garcia, Erica A., additional, García Lago, Liliana, additional, García Soto, Pavel Ernesto, additional, Ghate, Sudeep, additional, Giling, Darren P., additional, Gilmer, Alan, additional, Gonçalves, José Francisco, additional, Gonzales, Rosario Karina, additional, Graça, Manuel A. S., additional, Grace, Mike, additional, Grossart, Hans-Peter, additional, Guérold, François, additional, Gulis, Vlad, additional, Hepp, Luiz U., additional, Higgins, Scott, additional, Hishi, Takuo, additional, Huddart, Joseph, additional, Hudson, John, additional, Imberger, Samantha, additional, Iñiguez-Armijos, Carlos, additional, Iwata, Tomoya, additional, Janetski, David J., additional, Jennings, Eleanor, additional, Kirkwood, Andrea E., additional, Koning, Aaron A., additional, Kosten, Sarian, additional, Kuehn, Kevin A., additional, Laudon, Hjalmar, additional, Leavitt, Peter R., additional, Lemes da Silva, Aurea L., additional, Leroux, Shawn J., additional, LeRoy, Carri J., additional, Lisi, Peter J., additional, MacKenzie, Richard, additional, Marcarelli, Amy M., additional, Masese, Frank O., additional, McKie, Brendan G., additional, Oliveira Medeiros, Adriana, additional, Meissner, Kristian, additional, Miliša, Marko, additional, Mishra, Shailendra, additional, Miyake, Yo, additional, Moerke, Ashley, additional, Mombrikotb, Shorok, additional, Mooney, Rob, additional, Moulton, Tim, additional, Muotka, Timo, additional, Negishi, Junjiro N., additional, Neres-Lima, Vinicius, additional, Nieminen, Mika L., additional, Nimptsch, Jorge, additional, Ondruch, Jakub, additional, Paavola, Riku, additional, Pardo, Isabel, additional, Patrick, Christopher J., additional, Peeters, Edwin T. H. M., additional, Pozo, Jesus, additional, Pringle, Catherine, additional, Prussian, Aaron, additional, Quenta, Estefania, additional, Quesada, Antonio, additional, Reid, Brian, additional, Richardson, John S., additional, Rigosi, Anna, additional, Rincón, José, additional, Rîşnoveanu, Geta, additional, Robinson, Christopher T., additional, Rodríguez-Gallego, Lorena, additional, Royer, Todd V., additional, Rusak, James A., additional, Santamans, Anna C., additional, Selmeczy, Géza B., additional, Simiyu, Gelas, additional, Skuja, Agnija, additional, Smykla, Jerzy, additional, Sridhar, Kandikere R., additional, Sponseller, Ryan, additional, Stoler, Aaron, additional, Swan, Christopher M., additional, Szlag, David, additional, Teixeira-de Mello, Franco, additional, Tonkin, Jonathan D., additional, Uusheimo, Sari, additional, Veach, Allison M., additional, Vilbaste, Sirje, additional, Vought, Lena B. M., additional, Wang, Chiao-Ping, additional, Webster, Jackson R., additional, Wilson, Paul B., additional, Woelfl, Stefan, additional, Xenopoulos, Marguerite A., additional, Yates, Adam G., additional, Yoshimura, Chihiro, additional, Yule, Catherine M., additional, Zhang, Yixin X., additional, and Zwart, Jacob A., additional

Published
2019
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195. Regional versus local drivers of water quality in the Windermere catchment, Lake District, United Kingdom:The dominant influence of wastewater pollution over the past 200 years

Author

Moorhouse, Heather Louise, McGowan, Suzanne, Taranu, Zofia, Gregory-Eaves, Irene, Leavitt, Peter R., Jones, Matthew, Barker, Philip Anthony, Brayshaw, Susan, Moorhouse, Heather Louise, McGowan, Suzanne, Taranu, Zofia, Gregory-Eaves, Irene, Leavitt, Peter R., Jones, Matthew, Barker, Philip Anthony, and Brayshaw, Susan

Abstract

Freshwater ecosystems are threatened by multiple anthropogenic stressors acting over different spatial and temporal scales, resulting in toxic algal blooms, reduced water quality and hypoxia. However, while catchment characteristics act as a ‘filter’ modifying lake response to disturbance, little is known of the relative importance of different drivers and possible differentiation in the response of upland remote lakes in comparison to lowland, impacted lakes. Moreover, many studies have focussed on single lakes rather than looking at responses across a set of individual, yet connected lake basins. Here we used sedimentary algal pigments as an index of changes in primary producer assemblages over the last ~200 years in a northern temperate watershed consisting of 11 upland and lowland lakes within the Lake District, United Kingdom, to test our hypotheses about landscape drivers. Specifically, we expected that the magnitude of change in phototrophic assemblages would be greatest in lowland rather than upland lakes due to more intensive human activities in the watersheds of the former (agriculture, urbanization). Regional parameters, such as climate dynamics, would be the predominant factors regulating lake primary producers in remote upland lakes and thus, synchronize the dynamic of primary producer assemblages in these basins. We found broad support for the hypotheses pertaining to lowland sites as wastewater treatment was the main predictor of changes to primary producer assemblages in lowland lakes. In contrast, upland headwaters responded weakly to variation in atmospheric temperature, and dynamics in primary producers across upland lakes were asynchronous. Collectively, these findings show that nutrient inputs from point sources overwhelm climatic controls of algae and nuisance cyanobacteria, but highlights that large‐scale stressors do not always initiate coherent regional lake response. Furthermore, a lake's position in its landscape, its connectivity and prox

Published
2018

197. Resource‐use, body condition and parasite load metrics indicate contrasting health of stocked and native game fishes in Canadian prairie lakes.

Author

Nanayakkara, Lushani, Starks, Elizabeth R., Cooper, Ryan N., Chow, Sydney, Leavitt, Peter R., and Wissel, Björn

Subjects
NATIVE fishes, FORAGE fishes, PIKE, WALLEYE (Fish), YELLOW perch
Abstract

This study evaluated the status of native and stocked fish species in 13 prairie lakes in central Canada over eight years (2007–14) using three metrics: resource‐use (benthic versus pelagic carbon via stable isotopes); body condition (relative weight index Wr); and parasite load (cestode gut enumerations). Analyses included game and non‐game fishes, like naturally occurring northern pike, Esox lucius L., and yellow perch, Perca flavescens Mitchill, but focused on stocked walleye, Sander vitreus (Mitchill) because it supports a robust recreational fishery. Walleye and northern pike were significantly more reliant on benthic carbon than yellow perch or forage fishes (p < 0.05), but this reliance was not associated with any measured environmental variables for any species. In lakes with game fishes, forage fishes exhibited higher reliance on benthic energy, possibly due to predator avoidance strategy, particularly yellow perch. Walleye body condition index was consistently lower (<95–105) than values exhibited by the other two game fishes (81–139), and parasites were only common in walleye and associated with lake‐water salinity (r2 = 0.93, p < 0.05) and sex (p < 0.05). Based on the results, the most desirable game fish, walleye, appears less resilient to environmental variability than northern pike and yellow perch, making this species more susceptible to impacts of future climate change. [ABSTRACT FROM AUTHOR]

Published
2021
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198. Ecological dynamics of a peri-urban lake: a multi-proxy paleolimnological study of Cultus Lake (British Columbia) over the past ~ 200 years.

Author

Gauthier, Joanna, Gregory-Eaves, Irene, Bunting, Lynda, Leavitt, Peter R., Tran, Tanya, Godbout, Lyse, Finney, Bruce P., Schindler, Daniel E., Chen, Guangjie, Holtgrieve, Gordon, Shapley, Mark, and Selbie, Daniel T.

Subjects
ECOSYSTEM dynamics, CULTS, EFFECT of human beings on climate change, EUTROPHICATION, SOCKEYE salmon, WATERSHED management, CARBON cycle
Abstract

Peri-urban lakes offer many valued ecosystem services, but their vulnerability to climate change and anthropogenic disturbances increases with increasing human populations the effects and interactions of multiple stressors on lakes can lead to unexpected outcomes, affecting societal and ecological values, it is necessary to evaluate ecosystem trajectories and respective drivers in peri-urban lakes. Better management practices could thus be applied to preserve ecosystem services of peri-urban lakes. We conducted a multi-proxy paleolimnological study on Cultus Lake, British Columbia, a Canadian peri-urban lake experiencing cultural eutrophication, to reconstruct a comprehensive ecological trajectory of the lake over the past ~ 200 years. We also integrated historical data as well as historical archival information to identify the potential drivers of the changes. We identified ca. 1800–1900 CE as a reference period, reflected in muted variations across most paleo-indicators. Minor increases in sedimentary δ15N ca. 1880–1940 CE coincided with the onset of anthropogenic modifications to the Cultus Lake watershed. Signs of early eutrophication were evident by ca. 1940 CE, as indicated by increases in all sedimentary pigments. By ca. 1970–1990 CE, elevated concentrations of sedimentary cyanobacterial pigments and changes in diatom species assemblages highlighted the potential interactive effects of multiple stressors, including cultural eutrophication, climate warming and declines in the endangered Cultus Lake sockeye salmon population. Recent (ca. 1990–2008 CE) declines in sedimentary pigments and increases in cladoceran fluxes suggested an increase in top-down control of the lake food web. From the collection of changes observed in the past ~ 200 years in our study, it is clear that Cultus Lake and its associated ecosystem services would benefit from abatement of nutrient loadings from terrestrial and atmospheric sources. Our study emphasizes the complexity and interactivity of drivers in peri-urban lake ecosystems and the necessity of long-term perspectives to contextualize modern ecological conditions to inform lake and watershed management. [ABSTRACT FROM AUTHOR]

Published
2021
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