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Effects of the Distribution of a Toxic Microcystis Bloom on the Small Scale Patchiness of Zooplankton.

Reichwaldt ES, Song H, Ghadouani A - PLoS ONE (2013)

Bottom Line: However, little is known about how the patchy occurrence of blooms within systems affects the spatial distribution of zooplankton communities.While toxic Microcystis was present at all sites, there were large spatial differences in the level of cyanobacterial biomass and in the zooplankton communities; sites with persistently low cyanobacterial biomass displayed a higher biomass of adult Daphnia and higher zooplankton diversity than sites with persistently high cyanobacterial biomass.Overall, our study suggests that even in small systems with extensive blooms 'refuge sites' exist that allow large grazers to persist, which can be an important mechanism for a successful re-establishment of the biodiversity in an ecosystem after periods of cyanobacterial blooms.

View Article: PubMed Central - PubMed

Affiliation: Aquatic Ecology and Ecosystem Studies, School of Environmental Systems Engineering, The University of Western Australia, Crawley, Western Australia, Australia.

ABSTRACT
Toxic cyanobacterial blooms can strongly affect freshwater food web structures. However, little is known about how the patchy occurrence of blooms within systems affects the spatial distribution of zooplankton communities. We studied this by analysing zooplankton community structures in comparison with the spatially distinct distribution of a toxic Microcystis bloom in a small, shallow, eutrophic lake. While toxic Microcystis was present at all sites, there were large spatial differences in the level of cyanobacterial biomass and in the zooplankton communities; sites with persistently low cyanobacterial biomass displayed a higher biomass of adult Daphnia and higher zooplankton diversity than sites with persistently high cyanobacterial biomass. While wind was the most likely reason for the spatially distinct occurrence of the bloom, our data indicate that it was the differences in cyanobacterial biomass that caused spatial differences in the zooplankton community structures. Overall, our study suggests that even in small systems with extensive blooms 'refuge sites' exist that allow large grazers to persist, which can be an important mechanism for a successful re-establishment of the biodiversity in an ecosystem after periods of cyanobacterial blooms.

No MeSH data available.


Related in: MedlinePlus

Biomass of phytoplankton and zooplankton groups averaged over time for each site.Dashed line indicates 50%. Bosmina biomass was omitted as it was <1% at all dates.
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pone-0066674-g004: Biomass of phytoplankton and zooplankton groups averaged over time for each site.Dashed line indicates 50%. Bosmina biomass was omitted as it was <1% at all dates.

Mentions: Using the biomass of phytoplankton and zooplankton groups at each site averaged over time as a descriptor of the sites’ community structures, cyanobacteria were dominant (i.e. >50%) at sites 4 and 5 while their mean biomass was lowest at sites 6 and 7 (Fig. 4). At the same time, Daphnia biomass was dominant, with a large fraction of adult Daphnia, at sites 6 (27.3%) and 7 (27.2%), while calanoid copepods were dominant at all other sites.


Effects of the Distribution of a Toxic Microcystis Bloom on the Small Scale Patchiness of Zooplankton.

Reichwaldt ES, Song H, Ghadouani A - PLoS ONE (2013)

Biomass of phytoplankton and zooplankton groups averaged over time for each site.Dashed line indicates 50%. Bosmina biomass was omitted as it was <1% at all dates.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3686710&req=5

pone-0066674-g004: Biomass of phytoplankton and zooplankton groups averaged over time for each site.Dashed line indicates 50%. Bosmina biomass was omitted as it was <1% at all dates.
Mentions: Using the biomass of phytoplankton and zooplankton groups at each site averaged over time as a descriptor of the sites’ community structures, cyanobacteria were dominant (i.e. >50%) at sites 4 and 5 while their mean biomass was lowest at sites 6 and 7 (Fig. 4). At the same time, Daphnia biomass was dominant, with a large fraction of adult Daphnia, at sites 6 (27.3%) and 7 (27.2%), while calanoid copepods were dominant at all other sites.

Bottom Line: However, little is known about how the patchy occurrence of blooms within systems affects the spatial distribution of zooplankton communities.While toxic Microcystis was present at all sites, there were large spatial differences in the level of cyanobacterial biomass and in the zooplankton communities; sites with persistently low cyanobacterial biomass displayed a higher biomass of adult Daphnia and higher zooplankton diversity than sites with persistently high cyanobacterial biomass.Overall, our study suggests that even in small systems with extensive blooms 'refuge sites' exist that allow large grazers to persist, which can be an important mechanism for a successful re-establishment of the biodiversity in an ecosystem after periods of cyanobacterial blooms.

View Article: PubMed Central - PubMed

Affiliation: Aquatic Ecology and Ecosystem Studies, School of Environmental Systems Engineering, The University of Western Australia, Crawley, Western Australia, Australia.

ABSTRACT
Toxic cyanobacterial blooms can strongly affect freshwater food web structures. However, little is known about how the patchy occurrence of blooms within systems affects the spatial distribution of zooplankton communities. We studied this by analysing zooplankton community structures in comparison with the spatially distinct distribution of a toxic Microcystis bloom in a small, shallow, eutrophic lake. While toxic Microcystis was present at all sites, there were large spatial differences in the level of cyanobacterial biomass and in the zooplankton communities; sites with persistently low cyanobacterial biomass displayed a higher biomass of adult Daphnia and higher zooplankton diversity than sites with persistently high cyanobacterial biomass. While wind was the most likely reason for the spatially distinct occurrence of the bloom, our data indicate that it was the differences in cyanobacterial biomass that caused spatial differences in the zooplankton community structures. Overall, our study suggests that even in small systems with extensive blooms 'refuge sites' exist that allow large grazers to persist, which can be an important mechanism for a successful re-establishment of the biodiversity in an ecosystem after periods of cyanobacterial blooms.

No MeSH data available.


Related in: MedlinePlus