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Biology Articles » Ecology » Effects of removing symbiotic green algae on the response of Hydra viridissima (Pallas 1776) to metals

Effects of removing symbiotic green algae on the response of Hydra viridissima (Pallas 1776) to metals

Effects of removing symbiotic green algae on the response of Hydra viridissima (Pallas 1776) to metals

W. Karntanut and D. Pascoe

School of Biosciences, Cardiff University, Main Building, P.O. Box 915, Cardiff CF10 3TL, UK

Hydra viridissima is distinctively green due to symbiotic algae within the endodermal cells. The current investigation was designed to see if these algae influenced the response of Hydra to pollutants, by comparing the toxicity of copper, cadmium, and zinc to both symbiotic and aposymbiotic (free of their endosymbiotic algae) H. viridissima. The results demonstrated that the toxicity of the metals was generally similar for both groups of Hydra. However, at the lowest copper concentrations there was a difference between the two group of polyps, with aposymbiotic animals dying at concentrations where symbiotic Hydra survived. The lowest observed effect concentrations were 0.0068 and 0.016 mg/L for aposymbiotic and symbiotic Hydra, respectively. It is suggested that the symbiotic Hydra derive benefits from the association that enable them to better tolerate the toxicant. This work demonstrated that experimental manipulation of symbionts can help to explain their complex interactions and the ways in which they respond to pollutants.

Keywords: Hydra viridissima; Symbiosis; Aposymbiosis; Green algae; Toxicity; Copper; Cadmium; Zinc

Source: Ecotoxicology and Environmental Safety, Volume 60, Issue 3 , March 2005, Pages 301-305. Copyright © 2004 Elsevier Inc.


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