Browsing by Author "Lee, MR"

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    An assessment of the potential use of the nematode to copepod ratio in the monitoring of metals pollution. The Chanaral case
    (2001) Lee, MR; Correa, JA; Castilla, JC
    We discuss the use of the nematode to copepod ratio in relation to determining the extent of metals impact using the Chanaral area of northern Chile, where the dumping of copper mine tailings has taken place for many years, as an example. Data were collected from 12 beaches in the area on eight occasions between January 1997 and October 1998. We find that the ratio is not a good predictor of pollution due to the generally low densities of meiofauna on impacted beaches and the absence of harpacticoid copepods from those beaches. We suggest that in the case of metal pollution the mean number of Harpacticoida per site may be a better indicator of impact stress. We rule out the use of the nematode to copepod ratio as an indicator in biomonitoring studies where metal enrichment is thought to occur. (C) 2001 Elsevier Science Ltd. All rights reserved.
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    Copper mine tailings disposal
    (2004) Lee, MR; Correa, JA
    The hypothesis investigated in this paper is that the interstitial polychaetc Saccocirrus sonomacus is excluded from beaches impacted by tailing disposal as a result of the blocking of the interstitial space and not by a response to the toxicity of elevated copper concentrations. Field evidence suggested that abundances of S. sonomacus on beaches where they would be expected to occur under natural conditions are lower when a beach has received a significant amount of tailings. In choice experiments, S. sonomacus always preferred an open coarse sand matrix to one where the interstitial spaces had been blocked by fine sand (a tailings substitute). Using in vitro bioassays, we found that the LC50 for S. sonomacus with copper was 44 mug Cu l(-1), this being higher than the values of interstitial labile copper measured on the beaches investigated in this study. We therefore accept the hypothesis of a physically mediated exclusion rather than a toxically mediated one.