Marine Ecosystems under Toxic Pressure - Vulnerability of Coastal Ecosystems and Adaptation - page 9

Figure 1.1. Example of the marine trophic chain
1.3. What is the biological response of organisms to contaminants?
The absorption of a contaminant by a living organism triggers a
disruption in its metabolism. This disruption leads to a biological
response, which results either in the cell returning to its non-disturbed
state or in a manifestation of toxic effects. An organism's biological
response to a toxin can be seen as the result of the interaction between
the intrinsic properties of the substance and those of the organism
exposed to it. It depends on the chemical properties of the contaminant
(structure, activity and mode of action) and the physiological,
biological and ecological properties that characterize the organism at
the moment in its life when it is exposed to this contaminant. It is also
variable within a single species and a single age group, depending on
individuals. For example, many of us are exposed to the flu virus each
winter, and only some will actually become ill. Its general
physiological state has, in effect, an impact on the reaction of an
organism in the face of a stressor. Each species, and each individual