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Burlington, Canada

Munawar M.,Canadian Department of Fisheries and Oceans | Munawar I.F.,Plankton Canada | Fitzpatrick M.,Canadian Department of Fisheries and Oceans
Aquatic Ecosystem Health and Management | Year: 2013

A structural and functional assessment of the microbial foodweb of Lakes Superior, Huron, Erie and Ontario was undertaken during late summer (August) between 2001 and 2004. One lake was sampled in each year. Our analysis included microscopic enumerations of bacteria, autotrophic picoplankton, phytoplankton, heterotrophic nanoflagellates and ciliates coupled with radioisotope tracer measurements of primary productivity (14C) and bacterial growth (3H). Phytoplankton biomass was highest on average in Lake Erie (≈1.9 g m-3) and lowest in Lake Ontario (≈0.2 g m-3), whereas microbial loop biomass was highest in Lake Ontario (≈2.4 g m-3) and lowest in Lake Huron (≈0.1 g m-3). The organic carbon pool was found to be predominantly autotrophic (>80%) in Lakes Superior (≈280 mg C m-3), Huron (≈195 mg C m-3) and Erie (≈660 mg C m-3) and smaller picoplankton had the highest carbon turnover rates (≈0.4-1.5 d-1). However, in Lake Ontario (≈335 mg C m-3) the carbon pool was about 75% heterotrophic and larger net plankton had the highest carbon turnover rates (≈6.8 d-1). Despite differences in trophic state, the microbial foodwebs of Lakes Superior, Huron and Erie appeared to function in a similar and efficient manner. In contrast, the microbial foodweb of Lake Ontario appeared to be unhealthy with autochthonous production being sequestered by heterotrophic nanoflagellates. More detailed work is needed to understand the foodweb linkages both within the Great Lakes and among them. © 2013 Copyright Taylor and Francis Group, LLC. Source


Munawar M.,Canadian Department of Fisheries and Oceans | Fitzpatrick M.,Canadian Department of Fisheries and Oceans | Munawar I.F.,Plankton Canada | Niblock H.,Canadian Department of Fisheries and Oceans | Kane D.,Defiance College
Aquatic Ecosystem Health and Management | Year: 2012

Large freshwater and marine ecosystems suffer from a variety of anthropogenic stressors which include eutrophication, chemical contamination, coastal degradation and overexploitation of fisheries to name only a few. Attempts at remediation are often confounded by the multitude of local, regional, national and international governments and agencies that exercise jurisdiction over smaller parts of these ecosystems. In the North American Great Lakes, there exists a (nearly) 40 year track record for international cooperation in managing anthropogenic stressors that emphasizes sound ecosystem based science. Among these efforts was the designation of 42 severely polluted coastal regions as Areas of Concern (AoCs) which were deemed to have at least 1 of 14 possible Beneficial Use Impairments. The Bay of Quinte, Lake Ontario, is one AoC with 10 listed impairments. We used a "battery of tests" strategy to assess the health of the bay with respect to the impairments of "eutrophication or undesirable algae" and "degradation of phytoplankton and zooplankton communities" in the bay. This strategy integrates structural, functional and chemical parameters into established ecosystem health models. The results of the battery of tests showed continued eutrophication of the bay and not coincidentally, continued degradation of the phytoplankton community. We also found that point sources of phosphorous do not account for all of the (pelagic) primary production observed in the bay and suggest that non-point sources of phosphorous contribute significantly to eutrophication. Our results further suggest that the battery of tests strategy is a sensitive science-based tool for assessing ecosystem health. These tests could also be applied to the evaluation of ecosystem health in other Great Lakes AoCs as well as large lakes and marine environments where cultural eutrophication is a problem. © 2012 Copyright Taylor and Francis Group, LLC. Source


Munawar M.,Canadian Department of Fisheries and Oceans | Munawar I.F.,Plankton Canada | Fitzpatrick M.,Canadian Department of Fisheries and Oceans | Niblock H.,Canadian Department of Fisheries and Oceans | Lorimer J.,Aquatic Ecosystem Health and Management Society
Aquatic Ecosystem Health and Management | Year: 2014

A unique science and management strategy has been developed for the Laurentian Great Lakes due to their enormous size, geographic-ecological diversity, political and economic importance. This article is a documentary of more than 40 years of research conducted at the base of the foodweb by Fisheries and Oceans Canada, which has contributed significantly to the management of the Great Lakes. In the 1960s, the governments of Canada and the United States responded to the threat of cultural eutrophication which eventually resulted in the signing of the binational Great Lakes Water Quality Agreement. Dr. R. A. Vollenweider and Dr. J. R. Vallentyne were instrumental in developing a phosphorus abatement program, as well as the adoption of the “ecosystem approach” resulting in an holistic and integrated protocol for managing multiple environmental stressors. By showcasing some selected examples (Lake Ontario, Bay of Quinte, current research activities), an attempt is made to chronicle the evolution of phytoplankton, primary productivity and microbial foodweb research in the Great Lakes. Some of the research programs, techniques, models, policies and international cooperation are highlighted, in addition to the strong European influences on Great Lakes research. The lessons learned from the long-term Great Lakes research experience could be extrapolated and applied to enhance understanding of the ecology and management of other large lake ecosystems throughout the world. © 2014, Copyright © AEHMS. Source


Munawar M.,Canadian Department of Fisheries and Oceans | Munawar I.F.,Plankton Canada | Fitzpatrick M.,Canadian Department of Fisheries and Oceans | Niblock H.,Canadian Department of Fisheries and Oceans | Lorimer J.,Canadian Department of Fisheries and Oceans
Aquatic Ecosystem Health and Management | Year: 2015

The phytoplankton community of Lake Ontario was assessed during April, July and September 2008 as part of the Cooperative Science and Monitoring Initiative (CSMI) framework. Results were also compared with historic surveys that began in 1970. A total of 320 unique species were identified during 2008, the vast majority being considered ‘rare’ or ‘less common’. The biomass was found to be, on average, 1.6 g m−3 in spring, 3.0 g m−3 in early summer and 2.4 g m−3 in late summer with rare and less common species accounting for 60–80% of the total. Analysis of the size structure of the phytoplankton community combined with size fractionated primary productivity experiments revealed that one picoplankton (<2 μm) species, Chroococcus dispersus var. minor, accounted for up to half of the observed primary productivity, despite contributing 1% or less to total biomass. Our results also showed that the lake was mesotrophic during the summer of 2008 (July and September) and that trophic state has fluctuated between hyper-eutrophic and ultra-oligotrophic since monitoring began in 1970. These findings demonstrate that the Lake Ontario ecosystem is continually changing and more frequent sampling is needed. A high level of taxonomic expertise is required for even the most basic assessments of the phytoplankton community structure and improved taxonomic training and implementation of standardized techniques are necessary. © 2015, Copyright © 2015 Crown copyright. Source

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