Marine Ecosystems under Toxic Pressure - Vulnerability of Coastal Ecosystems and Adaptation - page 38

in the modulation sodium channels, which would lead to vulnerability
in the nervous system [NAR 00].
Species living at the limits of their homeostatic or physiological
tolerance will then be the most vulnerable to the double stress caused
by climate change and exposure to contaminants [GOR 03, HEA 94,
PAT 07]. In effect, the capacity of species and populations to tolerate
raised temperatures can be altered by toxic products. This double
exposure acts as a “co-stressor”: the toxic substances affecting the
physiological functions can diminish the capacity of organisms to
maintain homeostasy [BRO 04]. Ectoderms, like fish, are particularly
vulnerable to these temperature-contaminant interactions. The
capacity of brook trout ( Salvelinus fontinalis ) and Atlantic salmon
( Salmo salar ) to acclimatize to an increase in temperature is weakened
by sublethal doses of DDT [AND 69].
Moreover, modifications in habitat and trophic networks caused by
climate change can affect the toxicity of contaminants by modifying
the means of exposure and the sensitivity of certain populations, in
particular those that are already in a stress situation [BRE 04, BRO 02,
GAS 03, GIL 03, MAC 05].
Finally, these interactions between climate change and exposure to
contaminants will also be dependent on the life stage subject to
this exposure. In effect, the sensitive stages of life induce
responses that, in their turn, modify the physiological processes. This
process is particularly marked in contamination by endocrine
disruptors [BRI 08].
1.6. Conclusion
Marine ecotoxicology is a very recent avenue of research. Until the
1990s, the dilution capacity of the oceans appeared to be so great that
a “drop of PCB in the sea” would not have any consequences...
Indeed, it is no longer possible to ignore the harmful impact of
xenobiotic contaminants. First, it has been proved that they are present
in the confines of the ocean, in the environment as much as in the
fauna to which it is home. Second, the chronic toxicity that they cause