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PH08 Metals in the Environment: Aquatic Biological Perspectives
(PH091) The effects of copper, silver, nickel, and selenium exposure on the sea urchin, Diadema antillarum.
Bielmyer, G1, 2, Brix, K2, Capo, T1, Grosell, M1, 1 RSMAS, University of Miami, Miami, Fl., USA2 ECOTOX, Key Biscayne, Fl, USA
ABSTRACT- Since the massive population decline of the long-spined sea urchin, Diadema antillarum, in the early 1980's the dynamics of coral reef ecosystems in the Caribbean have changed tremendously. The absence of D. antillarum, once a keystone herbivore, has led to macroalgal dominance in many of these reef communities. The recovery of sea urchin populations in recent years has begun to shift these communities back toward predominantly coral reef coverage. D. antillarum is not only important ecologically, but may also be a sensitive bioindicator species for toxicant exposure. Adult sea urchins were exposed to aqueous copper (total Cu concentrations = 0, 1, 2, 4, 6, 13, 25, 48 ug Cu/L) under flow through conditions for 96-h. Mortality occurred in the two highest Cu treatments (96-h LC50 =24.87 ug/L dissolved Cu; 95% C.I.= 20.98, 29.49) and behavioral as well as physiological disturbance was observed. The physiological response included both acid-base disturbance, presumably due to respiratory impairment, and apparent ionoregulatory effects. Additionally, echinoderm larval development tests were conducted with D. antillarum exposed to elevated levels of aqueous copper, silver, nickel, or selenium. All metals significantly affected larval development, based on normal development to the pluteus stage. The EC50s were 11 ug/L dissolved Cu, 6 ug/L dissolved Ag, 113 ug/L nominal Ni, and 26 ug/L. dissolved Se. Sea urchin larva exposed to low levels of these metals had abnormal development to the pluteus stage and at higher concentrations did not develop past the blastula/gastrula stage. The sensitivity of both adult and larval Diadema to these metals supports the use of this organism as an important biological indicator for metal exposure in marine environments.
Key words: metal, Urchin, exposure
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