Investigating potential effects of zooplankton grazing on diatom-inferred drought reconstructions

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• 作者：Courtney R. Wigdahl-Perry ; Jasmine E. Saros ; Sherilyn C. Fritz ; C. T. Hess
• 关键词：Paleolimnology ; Cladocera ; Grazing ; Diatoms ; Salinity ; Transfer functions
• 刊名：Hydrobiologia
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：786
• 期：1
• 页码：149-165
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Freshwater & Marine Ecology; Ecology; Zoology;
• 出版者：Springer International Publishing
• ISSN：1573-5117
• 卷排序：786

文摘

Zooplankton may preferentially graze small, edible diatom species and therefore affect fossils relative to live assemblages by selective removal or increased sedimentation via egestion. Cladoceran zooplankton remains and diatom edibility were analyzed in sediment cores from Moon Lake and Coldwater Lake (North Dakota, USA) to assess changes in potential grazing pressure on algae and influence on diatom-inferred salinity (DIS) reconstructions. Sedimentary zooplankton in Moon Lake were dominated by littoral Cladocera, whereas Coldwater Lake assemblages were primarily small-bodied pelagic and littoral species. Relationships between cladocerans and environmental parameters over the past century varied by site and by species, with Chydorusbrevilabris related most closely to drought at Moon and Bosmina sp. related to drought at Coldwater. A higher percentage of inedible diatoms occurred in the sediments of Moon Lake as compared to Coldwater Lake. DIS correlations with drought records improved in Moon Lake when only inedible diatom taxa were used to build a transfer function, but no improvement was seen for Coldwater Lake with this approach. These data suggest grazing pressure on diatoms differed between lakes and that zooplankton–phytoplankton interactions may affect the accuracy of drought reconstructions in the Great Plains.