scholarly journals Open Lake Phosphorus Forcing of Cladophora Growth: Modeling the Dual Challenge in Great Lakes Trophic State Management

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2680
Author(s):  
Xing Zhou ◽  
Martin T. Auer ◽  
Pengfei Xue
Keyword(s):  
Great Lakes ◽  
Food Web ◽  
Algal Growth ◽  
Biophysical Model ◽  
Phosphorus Loading ◽  
Source Control ◽  
Local Source ◽  
Phosphorus Transport ◽  
State Management ◽  
Local Sources

Stimulated by excess levels of phosphorus, the attached, filamentous green alga Cladophora grows to nuisance proportions in Lake Michigan, one of the Laurentian Great Lakes. While nearshore waters impacted by local sources of the nutrient continue to support nuisance conditions, offshore waters have undergone oligotrophication in response to reductions in phosphorus loading and benthification of phosphorus cycling by invasive dreissenid mussels. A concept termed the Dual Challenge recognizes that implementation of more stringent phosphorus-loading objectives (to control Cladophora in the nearshore) stands in conflict with a foreseen need to mitigate oligotrophication in the offshore (to sustain a healthy fishery). Attention to this nearshore–offshore dynamic calls into play the role of cross-margin phosphorus transport in mediating both endmembers of the conflict. We applied a biophysical model simulating soluble reactive (SRP) and particulate (PP) phosphorus, mussel biokinetics, and cross-margin mass transport in addressing the Dual Challenge. Pre- and post-dreissenid monitoring results suggest that a reduction in offshore PP levels (food web nutrition) in excess of 40% (2.4 to 1.4 mgP×m−3) has driven oligotrophication and attendant food web dysfunction. Yet, in the absence of local sources, model-predicted nearshore SRP levels remain at or below those required to prevent nuisance growth. These findings indicate that there is a margin of ~1 mgP×m−3 over which offshore PP levels could be increased (to the benefit of the food web and the fishery) without hindering efforts to reduce nuisance algal growth through local source control.

The Contribution of Agricultural Loading to Eutrophication in Finnish Lakes

1985 ◽  
Vol 17 (6-7) ◽  
pp. 1133-1140 ◽  
Author(s):  
L. Kauppi
Keyword(s):  
Algal Growth ◽  
Industrial Effluents ◽  
Agricultural Runoff ◽  
Total Surface Area ◽  
Ionic Concentration ◽  
Phosphorus Loading ◽  
Available Phosphorus ◽  
Agricultural Activity ◽  
Nineteen Seventies ◽  
Spring Maximum

Agriculture accounts for 9 per cent of the total surface area of Finland and generates the greatest single nutrient input to Finnish watercourses. Since agricultural activity is scattered throughout the whole country its effects in lakes are less pronounced than those of domestic and industrial effluents. On the other hand, point source phosphorus loading of lakes and rivers decreased significantly during the nineteen-seventies. Phosphorus is the nutrient which primarily limits production in most Finnish lakes. The availability of phosphorus in agricultural runoff waters is therefore a crucial question in the evaluation of the eutrophicating effects of agriculture. Our results indicated that in runoff waters available phosphorus can be 60-70 per cent of the total phosphorus. However, the concentrations of available P were so low that they could be achieved in Finnish lakes of low ionic concentration through simple chemical desorption without the assistance of the algal uptake. The utilization of the spring maximum of runoff phosphorus in lakes would thus not depend on the concurrence of the maxima of loading and algal growth.

Assessment of mercury bioaccumulation within the pelagic food web of lakes in the western Great Lakes region

Ecotoxicology ◽  
2011 ◽  
Vol 20 (7) ◽  
pp. 1520-1529 ◽  
Author(s):  
Kristofer R. Rolfhus ◽  
Britt D. Hall ◽  
Bruce A. Monson ◽  
Michael J. Paterson ◽  
Jeffrey D. Jeremiason
Keyword(s):  
Great Lakes ◽  
Food Web ◽  
Great Lakes Region ◽  
Pelagic Food Web ◽  
Western Great Lakes ◽  
Mercury Bioaccumulation

Relative Importance of Phosphorus Supply to Phytoplankton Production: Fish Excretion versus External Loading

1990 ◽  
Vol 47 (2) ◽  
pp. 364-372 ◽  
Author(s):  
Åge Brabrand ◽  
Bjørn Andreas Faafeng ◽  
Jens Petter Moritz Nilssen
Keyword(s):  
Algal Growth ◽  
Perca Fluviatilis ◽  
Rutilus Rutilus ◽  
Phosphorus Release ◽  
Selenastrum Capricornutum ◽  
Phosphorus Loading ◽  
External Loading ◽  
Phytoplankton Production ◽  
Roach Rutilus Rutilus ◽  
Order Of Magnitude

In laboratory tanks with bream (Abramis brama), perch (Perca fluviatilis), and roach (Rutilus rutilus) concentrations of phosphorus and nitrogen increased with time. Phosphorus was mainly released as soluble molybdate-reactive phosphorus (SRP); nitrogen almost exclusively as ammonium. The release increased with the species' tendency to forage on littoral sediments and with a smaller fish size. Bioassays with the test algae Selenastrum capricornutum showed that released phosphorus was readily available to algal growth. The total supply of phosphorus to the epilimnion of Lake Gjersjøen was calculated from the external supply from the tributaries and the estimated phosphorus release from total roach biomass. From May to October 1980 phosphorus release from the roach population contributed about the same order of magnitude as the total phosphorus loading from the watershed. During the period with the most serious phosphorus depletion to the phytoplankton (July, August, and September), the phosphorus supply from fish was about double that of the external phosphorus supply, confirming the important role of sediment-feeding fish populations in the eutrophication processes of lakes.

scholarly journals Biological Indicators for Fecal Pollution Detection and Source Tracking: A Review

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2058
Author(s):  
Enze Li ◽  
Faizan Saleem ◽  
Thomas A. Edge ◽  
Herb E. Schellhorn
Keyword(s):  
Health Risks ◽  
Control Point ◽  
Algal Growth ◽  
Fecal Pollution ◽  
Point Sources ◽  
Mitigation Strategies ◽  
Source Control ◽  
Source Tracking ◽  
Potential Health ◽  
Pollution Detection

Fecal pollution, commonly detected in untreated or less treated sewage, is associated with health risks (e.g., waterborne diseases and antibiotic resistance dissemination), ecological issues (e.g., release of harmful gases in fecal sludge composting, proliferative bacterial/algal growth due to high nutrient loads) and economy losses (e.g., reduced aqua farm harvesting). Therefore, the discharge of untreated domestic sewage to the environment and its agricultural reuse are growing concerns. The goals of fecal pollution detection include fecal waste source tracking and identifying the presence of pathogens, therefore assessing potential health risks. This review summarizes available biological fecal indicators focusing on host specificity, degree of association with fecal pollution, environmental persistence, and quantification methods in fecal pollution assessment. The development of practical tools is a crucial requirement for the implementation of mitigation strategies that may help confine the types of host-specific pathogens and determine the source control point, such as sourcing fecal wastes from point sources and nonpoint sources. Emerging multidisciplinary bacterial enumeration platforms are also discussed, including individual working mechanisms, applications, advantages, and limitations.

scholarly journals Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan

2019 ◽  
Vol 116 (47) ◽  
pp. 23600-23608 ◽  
Author(s):  
Ryan F. Lepak ◽  
Joel C. Hoffman ◽  
Sarah E. Janssen ◽  
David P. Krabbenhoft ◽  
Jacob M. Ogorek ◽  
...  
Keyword(s):  
Invasive Species ◽  
Great Lakes ◽  
Food Web ◽  
Lake Michigan ◽  
Lake Trout ◽  
Mitigation Strategies ◽  
Predatory Fish ◽  
Isotopic Analyses ◽  
C And N ◽  
The Impact

To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources. Additionally, dietary tracers were necessary to identify food web influences. Through combined Hg, C, and N stable isotopic analyses, we were able to differentiate between a shift in Hg sources to fish and periods when energetic transitions (from dreissenid mussels) led to the assimilation of contrasting Hg pools (2000 to present). In the late 1980s, lake trout δ202Hg increased (0.4‰) from regulatory reductions in regional Hg emissions. After 2000, C and N isotopes ratios revealed altered food web pathways, resulting in a benthic energetic shift and changes to Hg bioaccumulation. Continued increases in δ202Hg indicate fish are responding to several United States mercury emission mitigation strategies that were initiated circa 1990 and continued through the 2011 promulgation of the Mercury and Air Toxics Standards rule. Unlike archives of sediments, this fish archive tracks Hg sources susceptible to bioaccumulation in Great Lakes fisheries. Analysis reveals that trends in fish Hg concentrations can be substantially affected by shifts in trophic structure and dietary preferences initiated by invasive species in the Great Lakes. This does not diminish the benefits of declining emissions over this period, as fish Hg concentrations would have been higher without these actions.

scholarly journals Eurasian tench (Tinca tinca): the next Great Lakes invader

2018 ◽  
Vol 75 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Sunčica Avlijaš ◽  
Anthony Ricciardi ◽  
Nicholas E. Mandrak
Keyword(s):  
Great Lakes ◽  
Algal Growth ◽  
Water Clarity ◽  
Ecological Impacts ◽  
Commercial Fishing ◽  
Tinca Tinca ◽  
Benthic Fishes ◽  
Tench Tinca Tinca ◽  
Natural Dispersal ◽  
St Lawrence River

A globally invasive fish, Eurasian tench (Tinca tinca) is spreading through the St. Lawrence River and poses an imminent invasion threat to the Great Lakes. Following its illegal release into a tributary of the St. Lawrence River in 1991, tench has spread throughout the river’s main stem over the past decade, and its abundance in commercial fishing bycatch in the river has grown exponentially. The tench is a generalist benthic consumer with largely undocumented ecological impacts in North America. Reports from other invaded regions indicate that it can compete with other benthic fishes, host a diverse assemblage of parasites and pathogens, degrade water clarity in shallow lakes, limit submerged macrophyte growth, reduce gastropod populations, and promote benthic algal growth through top-down effects. Risk assessments and climate-match models indicate that the Great Lakes are vulnerable to tench invasion, and they signal the need for timely comprehensive actions, including development and implementation of monitoring and rapid-response protocols, including prevention or slowing of natural dispersal through canals.

Depth-specific patterns in benthic–planktonic food web relationships in Lake Superior

2006 ◽  
Vol 63 (7) ◽  
pp. 1496-1503 ◽  
Author(s):  
Michael E Sierszen ◽  
Gregory S Peterson ◽  
Jill V Scharold
Keyword(s):  
Great Lakes ◽  
Food Web ◽  
Food Webs ◽  
Water Column ◽  
Trophic Position ◽  
Lake Superior ◽  
Benthic Algae ◽  
Isotope Ratios ◽  
Food Sources ◽  
Large Lakes

In an investigation of the spatial characteristics of Laurentian Great Lakes food webs, we examined the trophic relationship between benthic amphipods (Diporeia) and plankton in Lake Superior. We analyzed the carbon and nitrogen stable isotope ratios of Diporeia and plankton at stations in water column depths of 4–300 m. Neither δ15N nor δ13C of plankton from the upper 50 m of the water column varied significantly with station depth. Diporeia isotope ratios exhibited depth-specific patterns reflecting changes in food sources and food web relationships with plankton. Diporeia was 13C enriched at station depths of <40 m, reflecting increased dietary importance of benthic algae. There was a systematic increase in Diporeia δ15N with depth, which appeared to result from a combination of dietary shifts in the nearshore and decompositional changes in Diporeia's principal food, sedimented plankton, in deep habitats. Diporeia δ13C and δ15N together described changes in food web isotope baseline with depth. They also discriminated three depth strata representing photic, mid-depth, and profundal zones. These findings have implications for our understanding of Great Lakes food webs and analyses of trophic position within them, the ecology of zoobenthos and plankton communities, and sampling designs for large lakes.

scholarly journals Reviewing uncertainty in bioenergetics and food web models to project invasion impacts: Four major Chinese carps in the Great Lakes

2020 ◽  
Author(s):  
Kelly F. Robinson ◽  
Peter J. Alsip ◽  
Andrew R. Drake ◽  
Yu-Chun Kao ◽  
Marten A. Koops ◽  
...  
Keyword(s):  
Great Lakes ◽  
Food Web ◽  
Invasion Impacts ◽  
Chinese Carps

Rehabilitation of Lake Ontario: the Role of Nutrient Reduction and Food Web Dynamics

1991 ◽  
Vol 48 (8) ◽  
pp. 1574-1580 ◽  
Author(s):  
John H. Hartig ◽  
James F. Kitchell ◽  
Donald Scavia ◽  
Stephen B. Brandt
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Food Web ◽  
Toxic Substance ◽  
Lake Ontario ◽  
The United States ◽  
Food Web Dynamics ◽  
Food Web Interactions ◽  
The Impact

The Laurentian Great Lakes have a complex history of changes due to eutrophication, invasion of exotic species, and fisheries and phosphorus management practices. Remedial actions have reduced nutrient loadings and enhanced the role of food web interactions in improving water quality. Workshops sponsored through the United States – Canada international Joint Commission have addressed the relative importance of nutrient abatement and/or food web manipulation in affecting water quality trends. Both controls have combined to enhance water clarity in Lake Michigan. Lake Ontario has already exhibited the effects of nutrient controls and may be on the verge of manifesting food web controls. Research and monitoring recommendations to elucidate the effects of nutrient and food web controls include the following: (1) water quality and fisheries agencies must coordinate monitoring activities, standardize techniques, and establish and maintain long-term data sets to evaluate the effects of water quality and fisheries programs separately and together; (2) controlled, mesoscale, whole-system experiments should be performed to quantify rates (e.g. growth, predation, etc.) of food web interactions; and (3) the scientific community should promote research which quantifies the impact of changes in food web dynamics on changes in toxic substance levels in Great Lakes fishes.

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