The re-eutrophication of Lake Erie: Harmful algal blooms and hypoxia

Watson, Susan B.; Miller, Carol J.; Arhonditsis, George B.; Boyer, Gregory L.; Carmichael, Wayne W.; Charlton, Murray N.; Confesor, Remegio; Depew, David C.; Höök, Tomas O.; Ludsin, Stuart A.; Matisoff, Gerald; McElmurry, Shawn P.; Murray, Mary Ellen; Richards, R. Peter; Rao, Yerubandi R.; Steffen, Morgan M.; Wilhelm, Steven W.

doi:10.1016/j.hal.2016.04.010

Cited by 418 publications

(212 citation statements)

References 238 publications

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“…Since the mid 1990s, cyanobacteria blooms have re-occurred annually after a period of general algal decline starting in the mid 1970s as a response to water management mitigation efforts (Conroy et al, 2005;Kane et al, 2014;Watson et al, 2016). This fundamental shift in the plankton community to cyanobacteria has been linked to several causes, fueled by increased nutrient enrichment from changes in land use practices, introduction of dressinid mussels and changing weather patterns (Paerl, 2009;Paerl et al, 2011;Michalak et al, 2013).…”

Section: Study Sitementioning

confidence: 99%

Bio-optical Properties of Cyanobacteria Blooms in Western Lake Erie

et al. 2017

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There is a growing use of remote sensing observations for detecting and quantifying freshwater cyanobacteria populations, yet the inherent optical properties of these communities in natural settings, fundamental to bio-optical algorithms, are not well known. Toward bridging this knowledge gap, we measured a full complement of optical properties in western Lake Erie during cyanobacteria blooms in the summers of 2013 and 2014. Our measurements focus attention on the optical uniqueness of cyanobacteria blooms, which have consequences for remote sensing and bio-optical modeling. We found the cyanobacteria blooms in the western basin during our field work were dominated by Microcystis, while the waters in the adjacent central basin were dominated by Planktothrix. Chlorophyll concentrations ranged from 1 to over 135 µg/L across the study area with the highest concentrations associated with Microcystis in the western basin. We observed large, amorphous colonial Microcystis structures in the bloom area characterized by high phytoplankton absorption and high scattering coefficients with a mean particle backscatter ratio at 443 nm > 0.03, which is higher than other plankton types and more comparable to suspended inorganic sediments. While our samples contained mixtures of both, our analysis suggests high contributions to the measured scatter and backscatter coefficients from cyanobacteria. Our measurements provide new insights into the optical properties of cyanobacteria blooms, and indicate that current semi-analytic models are likely to have problems resolving a closed solution in these types of waters as many of our observations are beyond the range of existing model components. We believe that different algorithm or model approaches are needed for these conditions, specifically for phytoplankton absorption and particle backscatter components. From a remote sensing perspective, this presents a challenge not only in terms of a need for new algorithms, but also for determining when to apply the best Moore et al. Lake Erie IOPs algorithm for a given situation. These results are new in the sense that they represent a complete description of the optical properties of freshwater cyanobacteria blooms, and are likely to be representative of bloom conditions for other systems containing Microcystis cells and colonies.

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Section: Study Sitementioning

confidence: 99%

Bio-optical Properties of Cyanobacteria Blooms in Western Lake Erie

et al. 2017

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“…The Great Lakes receive nutrients from many tributaries draining areas ranging from pristine forests to intensively farmed areas and large urban centers, which results in nutrient input from these tributaries being extremely variable (Robertson and Saad ). Excessive nutrient inputs have caused eutrophication problems to various degrees and at scales ranging from bays around the Great Lakes (e.g., Green Bay in Lake Michigan, Maccoux et al , and Bay of Quinte in Lake Ontario, Minns et al ) to most of Lake Erie (Watson et al ). Because of the degradation in water quality, several national and binational efforts have been conducted to reduce nutrient loading to the Great Lakes, such as the binational Great Lakes Water Quality Agreement (GLWQA), the Great Lakes Restoration Initiative led by the U.S. Environmental Protection Agency (USEPA ), and the Great Lakes Nutrient Initiative led by Environment and Climate Change Canada (ECCC ).…”

Section: Introductionmentioning

confidence: 99%

Phosphorus and Nitrogen Transport in the Binational Great Lakes Basin Estimated Using SPARROW Watershed Models

Robertson

Saad

Benoy

et al. 2019

J American Water Resour Assoc

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Eutrophication problems in the Great Lakes are caused by excessive nutrient inputs (primarily phosphorus, P, and nitrogen, N) from various sources throughout its basin. In developing protection and restoration plans, it is important to know where and from what sources the nutrients originate. As part of a binational effort, Midcontinent SPARROW (SPAtially Referenced Regression On Watershed attributes) models were developed and used to estimate P and N loading from throughout the entire basin based on nutrient inputs similar to 2002; previous SPARROW models only estimated U.S. contributions. The new models have a higher resolution (~2‐km2 catchments) enabling improved descriptions of where nutrients originate and the sources at various spatial scales. The models were developed using harmonized geospatial datasets describing the stream network, nutrient sources, and environmental characteristics affecting P and N delivery. The models were calibrated using loads from sites estimated with ratio estimator and regression techniques and additional statistical approaches to reduce spatial correlation in the residuals and have all monitoring sites equally influence model development. SPARROW results, along with interlake transfers and direct atmospheric inputs, were used to quantify the entire P and N input to each lake and describe the importance of each nutrient source. Model results can be used to compare loading and yields from various tributaries and jurisdictions.

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“…17). An additional threat posed by cyanobacteria was found to come from Anabaena and Microcystis, which are toxigenic cyanobacteria (Watson et al, 2016). Cyanobacteria growth is promoted by changes of internal and external nutrient loadings and increased temperature (Conroy et al, 2005;McCormick and Fahnenstiel, 1999).…”

Section: Discussionmentioning

confidence: 99%

Effect of Diurnal Variation of Dissolved Oxygen in a Eutrophic Polymictic Reservoir

Balangoda¹

2017

American Journal of Environmental Sciences

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Abstract:To evaluate the diurnal and seasonal Dissolved Oxygen (DO) variations and their effects on water quality, a comprehensive study was conducted in a eutrophic polymictic reservoir under artificially aerated and non-aerated conditions. The effect of aeration among sampling locations and along the water column of DO and DO saturation and diurnal variation of DO, water temperature, pH and conductivity was evaluated under aerated and non-aerated conditions. Dissolved oxygen and water temperature exhibited diurnal variations under aerated and non-aerated conditions; however, no notable diurnal variation was observed in conductivity and pH. The anoxic condition was observed in near-bottom waters at night under non-aerated conditions. The diurnal DO concentration at the surface level was higher under non-aerated conditions than aerated conditions. The diurnal DO variation implies that excessive algae and weed growth cause a major impact on DO production and consumption during the day and night, respectively. The DO concentration at different sampling locations revealed that artificial aeration increased DO concentration in the deep portion of the reservoir. However, results showed that the existing aeration system was inadequate to increase the DO concentration in the entire reservoir.

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The re-eutrophication of Lake Erie: Harmful algal blooms and hypoxia

Cited by 418 publications

References 238 publications

Bio-optical Properties of Cyanobacteria Blooms in Western Lake Erie

Bio-optical Properties of Cyanobacteria Blooms in Western Lake Erie

Phosphorus and Nitrogen Transport in the Binational Great Lakes Basin Estimated Using SPARROW Watershed Models

Effect of Diurnal Variation of Dissolved Oxygen in a Eutrophic Polymictic Reservoir

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