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

Publication date: November 2019Source: Harmful Algae, Volume 89Author(s): Helen Agasild, Kristel Panksep, Ilmar Tõnno, Kätlin Blank, Toomas Kõiv, René Freiberg, Reet Laugaste, Roger I. Jones, Peeter Nõges, Tiina NõgesAbstractThe coexistence of potentially toxic bloom-forming cyanobacteria (CY) and generally smaller-sized grazer communities has raised the question of zooplankton (ZP) ability to control harmful cyanobacterial blooms and highlighted the need for species-specific research on ZP-CY trophic interactions in naturally occurring communities. A combination of HPLC, molecular and stable isotope analyses was used to assess in situ the importance of CY as a food source for dominant crustacean ZP species and to quantify the grazing on potentially toxic strains of Microcystis during bloom formation in large eutrophic Lake Peipsi (Estonia). Aphanizomenon, Dolichospermum, Gloeotrichia and Microcystis dominated bloom-forming CY, while Microcystis was the major genus producing cyanotoxins all over the lake. Grazing studies showed that CY, and especially colonial CY, formed a significant, and also preferred component of algae ingested by the cladocerans Bosmina spp. and Daphnia spp. while this was not the case for the more selective calanoid copepod Eudiaptomus gracilis. Molecular analyses confirmed the presence of CY, including Microcystis, in ZP guts. Further analyses using qPCR targeting cyanobacterial genus-specific mcyE synthase genes indicated that potentially toxic ...

Source: Harmful Algae - October 16, 2019 Category: Environmental Health Source Type: research