Role of potentially toxic cyanobacteria in crustacean zooplankton diet in a eutrophic lake

Harmful Algae ◽  
2019 ◽  
Vol 89 ◽  
pp. 101688
Author(s):  
Helen Agasild ◽  
Kristel Panksep ◽  
Ilmar Tõnno ◽  
Kätlin Blank ◽  
Toomas Kõiv ◽  
...  
Keyword(s):  
Eutrophic Lake ◽  
Crustacean Zooplankton ◽  
Toxic Cyanobacteria

scholarly journals The Role of Nitrogen Fixation in Cyanobacterial Bloom Toxicity in a Temperate, Eutrophic Lake

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e56103 ◽  
Author(s):  
Lucas J. Beversdorf ◽  
Todd R. Miller ◽  
Katherine D. McMahon
Keyword(s):  
Nitrogen Fixation ◽  
Cyanobacterial Bloom ◽  
Eutrophic Lake

scholarly journals Periods of Extreme Shallow Depth Hinder but Do Not Stop Long-Term Improvements of Water Quality in Lake Apopka, Florida (USA)

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 538 ◽  
Author(s):  
Gaohua Ji ◽  
Karl Havens
Keyword(s):  
Water Quality ◽  
Eutrophic Lake ◽  
Water Levels ◽  
Shallow Depth ◽  
Benthivorous Fish ◽  
Chl A ◽  
Lake Apopka ◽  
Toxic Cyanobacteria ◽  
Long Term Trends

We recently documented that during times of extreme shallow depth, there are severe effects on the water quality of one of the largest shallow lakes in the southeastern USA—Lake Apopka. During those times, total phosphorus (TP), total nitrogen (TN), chlorophyll-a (Chl-a) and toxic cyanobacteria blooms increase, and Secchi transparency (SD) declines. The lake recovers when water levels rise in subsequent years. In this paper, we determined whether extreme shallow depth events, particularly when they re-occur frequently, can stop the long-term recovery of a shallow eutrophic lake undergoing nutrient reduction programs. Apopka is an ideal location for this case study because the State of Florida has spent over 200 million USD in order to reduce the inputs of P to the lake, to build large filter marshes to treat the water, and to remove large quantities of benthivorous fish that contribute to internal P loading. We obtained data from 1985 to 2018, a period that had relatively stable water levels for nearly 15 years, and then three successive periods of extreme shallow depth, and we examined the long-term trends in TP, TN, Chl-a, and SD. There were significant decreasing trends in all of these water quality variables, and even though water quality deteriorated during periods of extreme shallow depth, and reduced the slope of the long-term trends, it did not stop the recovery. However, in the future, if climate change leads to more frequent shallow depth events, which in lakes such as Apopka, result in the concentration of water and nutrients, it is unclear whether the resilience we document here will continue, vs. the lake not responding to further nutrient input reductions.

scholarly journals Complex Interactions between Fish and Zooplankton: Quantifying the Role of an Open-Water Planktivore

1992 ◽  
Vol 49 (6) ◽  
pp. 1216-1227 ◽  
Author(s):  
Dennis R. DeVries ◽  
Roy A. Stein
Keyword(s):  
Open Water ◽  
Gizzard Shad ◽  
Crustacean Zooplankton ◽  
Dorosoma Cepedianum ◽  
Exclosure Experiment ◽  
Complex Interactions ◽  
Zooplankton Density ◽  
Algal Abundance ◽  
Reduced Density

An open-water planktivore, the gizzard shad (Dorosoma cepedianum), can drive complex interactions among fish and zooplankton in Ohio reservoirs. In Kokosing Lake, crustacean zooplankton density declined to near zero immediately after larval gizzard shad abundance peaked during 1987 and 1988. This decline can be attributed to increased death rates, due to predation, and to reduced number of eggs per cladoceran. In an enclosure/exclosure experiment, young-of-year gizzard shad at lake densities significantly reduced density of crustacean zooplankton and rotifers within 2 wk. In addition, phytoplankton that were edible to zooplankton were reduced in enclosures, likely due to a combination of direct herbivory by gizzard shad and reduced nutrient availability due to uptake by the growing gizzard shad. Gizzard shad not only directly influenced zooplankton via predation, they also indirectly affected zooplankton by reducing phytoplankton abundance. Because larval bluegill (Lepomis macrochira) migrated to the limnetic zone during or shortly after the zooplankton decline, food available to these zooplanktivorous larvae, as well as their ultimate recruitment, was reduced with gizzard shad. Through direct (i.e. predation) and indirect (i.e. influencing algal abundance) pathways, gizzard shad can drive zooplankton to extinction, thereby reducing recruitment of other fishes and controlling community composition.

scholarly journals Algal Diet of Small-Bodied Crustacean Zooplankton in a Cyanobacteria-Dominated Eutrophic Lake

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0154526 ◽  
Author(s):  
Ilmar Tõnno ◽  
Helen Agasild ◽  
Toomas Kõiv ◽  
Rene Freiberg ◽  
Peeter Nõges ◽  
...  
Keyword(s):  
Eutrophic Lake ◽  
Crustacean Zooplankton ◽  
Algal Diet

scholarly journals Genotyping and functional regression trees reveals environmental preferences of toxic cyanobacteria (Microcystis aeruginosa complex) along a wide spatial gradient

2019 ◽  
Author(s):  
Gabriela Martínez de la Escalera ◽  
Angel M. Segura ◽  
Carla Kruk ◽  
Badih Ghattas ◽  
Claudia Piccini
Keyword(s):  
Microcystis Aeruginosa ◽  
Environmental Conditions ◽  
Regression Trees ◽  
Spatial Gradient ◽  
Functional Regression ◽  
Environmental Preferences ◽  
Temperature Conductivity ◽  
Toxic Cyanobacteria ◽  
Melting Analysis

AbstractAddressing ecological and evolutionary processes explaining biodiversity patterns is essential to identify the mechanisms driving community assembly. In the case of bacteria, the formation of new ecologically distinct populations or ecotypes is proposed as one of the main drivers of diversification. New ecotypes arise when mutation in key functional genes or acquisition of new metabolic pathways by horizontal gene transfer allow the population to exploit new resources, making possible their coexistence with parental population. Recently, we have reported the presence of toxic, microcystin-producing organisms from the Microcystis aeruginosa complex (MAC) through a wide environmental gradient (800 km) in South America, ranging from freshwater to estuarine-marine waters. In order to explain this finding, we hypothesize that the success of toxic organisms of MAC in such array of environmental conditions is due to the existence of ecotypes having different environmental preferences. So, we analysed the genetic diversity of microcystin-producing populations of Microcystis aeruginosa complex (MAC) by qPCR and high resolution melting analysis (HRMA) of a functional gene (mcyJ, involved in microcystin synthesis) and explored its relationship with the environmental conditions through the gradient by functional classification and regression trees (fCART). Six groups of mcyJ genotypes were distinguished and selected by different combinations of water temperature, conductivity and turbidity, determining the environmental preferences of each group. Since these groups were based on the basis of similar sequence and ecological characteristics they were defined as ecotypes of toxic MAC. Taking into account that the role of microcystins in MAC biology and ecology has not yet been elucidated, we propose that the toxin might have a role in MAC fitness that would be mainly controlled by the physical environment in a way such that the ecotypes that thrive in the riverine zone of the gradient would be more stable and less influenced by salinity fluctuations than those living at the marine limit of the estuary. These would periodically disappear or being eliminated by salinity increases, depending on the estuary dynamics. Thus, ecotypes generation would be an important mechanism allowing toxic MAC adapting to and succeed in a wide array of environmental conditions.

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