Document Detail

Anomalous rise in algal production linked to lakewater calcium decline through food web interactions.
MedLine Citation:
PMID:  21957138     Owner:  NLM     Status:  MEDLINE    
Increased algal blooms are a threat to aquatic ecosystems worldwide, although the combined effects of multiple stressors make it difficult to determine the underlying causes. We explore whether changes in trophic interactions in response to declining calcium (Ca) concentrations, a water quality issue only recently recognized in Europe and North America, can be linked with unexplained bloom production. Using a palaeolimnological approach analysing the remains of Cladocera (herbivorous grazers) and visual reflectance spectroscopically inferred chlorophyll a from the sediments of a Nova Scotia (Canada) lake, we show that a keystone grazer, Daphnia, declined in the early 1990s and was replaced by a less effective grazer, Bosmina, while inferred chlorophyll a levels tripled at constant total phosphorus (TP) concentrations. The decline in Daphnia cannot be attributed to changes in pH, thermal stratification or predation, but instead is linked to declining lakewater [Ca]. The consistency in the timing of changes in Daphnia and inferred chlorophyll a suggests top-down control on algal production, providing, to our knowledge, the first evidence of a link between lakewater [Ca] decline and elevated algal production mediated through the effects of [Ca] decline on Daphnia. [Ca] decline has severe implications for whole-lake food webs, and presents yet another mechanism for potential increases in algal blooms.
Jennifer B Korosi; Samantha M Burke; Joshua R Thienpont; John P Smol
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-09-28
Journal Detail:
Title:  Proceedings. Biological sciences / The Royal Society     Volume:  279     ISSN:  1471-2954     ISO Abbreviation:  Proc. Biol. Sci.     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-02-10     Completed Date:  2012-10-02     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  101245157     Medline TA:  Proc Biol Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  1210-7     Citation Subset:  IM    
Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston Ontario, Canada.
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MeSH Terms
Calcium / analysis,  metabolism*
Chlorophyll / analysis,  metabolism
Chlorophyta / metabolism*,  physiology
Cladocera / physiology*
Daphnia / physiology
Feeding Behavior
Food Chain*
Lakes / chemistry*
Nova Scotia
Population Density
Population Dynamics
Reg. No./Substance:
1406-65-1/Chlorophyll; 7440-70-2/Calcium; YF5Q9EJC8Y/chlorophyll a

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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