SEMINAR: MBF 602 Seminar-Kok Yen Chan January 29th, 2010- S/A seminar room 4pm

[Cary Rios <crios@rsmas.miami.edu>]

Comparative study of copper effects on fish and blue crab across different salinities

 

Abstract

 

The osmoregulatory and ionoregulatory processes of aquatic animals are influence by ambient salinity. Estuarine species are challenged to alter their physiology constantly depending on ambient salinity changes. Salinity not only greatly influences ionic exchange and diffusive water movement but also the sensitivity of aquatic organisms to trace metals such as zinc, cadmium or copper. Metal concentrations in estuaries are often elevated as a result of anthropogenic activities creating a complex environmental problem of interactions between osmoregulation and metal toxicity. The interactions between salinities and acute toxic of metals in fish have received some attention, but limited information is available regarding interactions between intermediate salinities and cute toxicity in both euryhaline fish and invertebrates. Therefore, the main objective of this study is to investigate the mechanisms of interactions between ambient salinity and acute copper toxicity in the killifish and the blue crab. Copper is an essential micro-nutrient but acts as  a potent toxicant at elevated concentrations. Copper targets mainly the osmoregulatory processes and are thus expected to impact osmoregulators (killifish) and osmoconformers (blue crabs) differently at different salinities. The electrochemical gradients for Na+ across epithelia of fish and crabs at different salinities will be investigated by measuring the electrical potential and ionic gradients before and during exposure to copper.  Furthermore, sensitivity to copper is expected to be influenced by fluctuating rather than constant salinities and copper toxicity will therefore be determined under constant as well as tidal salinity changes. Finally, a salinity choice system established to measure the ‘preferred’ salinity for both fish and crabs will be employed to investigate possible behavioral responses mitigating physiological impairment arising from copper exposure. 

 

Kok Yeng Chan

 

B.S. Zoology, Universiti Sains Malaysia (2002)

M.Sc Aquatic, Universiti Sains Malaysia (2006)

Entered Ph.D. program in fall of 2008

Cary Rios 
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