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The effects of zinc on the structure and functioning of a freshwater community: A microcosm experiment
Author(s) -
Van de Perre Dimitri,
Roessink Ivo,
Janssen Colin R.,
Smolders Erik,
Van Regenmortel Tina,
Van Wichelen Jeroen,
Vyverman Wim,
Van den Brink Paul J.,
De Schamphelaere Karel A.C.
Publication year - 2016
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.3435
Subject(s) - plankton , microcosm , phytoplankton , mesocosm , biology , environmental chemistry , ecology , context (archaeology) , dominance (genetics) , chemistry , ecosystem , nutrient , biochemistry , paleontology , gene
A major problem with risk assessment of chemicals is the extrapolation of laboratory single‐species toxicity tests, which oversimplify the actual field situation by ignoring species interactions, to natural communities. The authors tested if the bioavailability‐normalized 5% hazardous concentration (HC5) estimated from chronic planktonic single‐species toxicity data (HC5 plankton ) for zinc (Zn) is protective for a plankton community and investigated the direct and indirect effects of Zn (at HC5 and HC50) on a freshwater community's structure and function. Microcosms were exposed to 3 different Zn concentrations (background, HC5 plankton = 75 μg Zn/L and HC50 plankton = 300 μg Zn/L) for 5 wk. The planktonic groups revealed a consistent no‐observed‐effect concentration for the community of 75 μg Zn/L, similar to or higher than the HC5 plankton , thus suggesting its protectiveness in the present study. At 300 μg Zn/L a significant reduction in cladocerans resulted in increases of rotifer, ciliate, and phytoplankton abundance. In addition, the phytoplankton community shifted in dominance from grazing‐resistant to edible species. Contrary to the species sensitivity distribution (SSD) prediction, which identified phytoplankton as the most sensitive group, only the total chlorophyll and the abundance of 2 phytoplankton species were adversely affected at 300 μg Zn/L. Thus, although the HC5 estimated from the bioavailability‐normalized SSD was overall protective for the plankton community, the SSD was not able to correctly predict the species sensitivity ranking within their community context at the HC50. Environ Toxicol Chem 2016;35:2698–2712. © 2016 SETAC