Environmental Engineering Reference
In-Depth Information
Fig. 1.
Temperature infl uence on aerobic metabolism of marine fi shes. The concentration of
dissolved oxygen ([O2]) in seawater varies negatively with temperature, and both variables
determine the fate of aerobic metabolism (solid curve) of fi shes. The aerobic capacity starts
to be restricted after a threshold temperature (optimal T) is surpasses, after the onset of the
anaerobic metabolism (dashed curve). When temperature continues to grow, the concentration
of dissolved oxygen becomes limiting and after the second threshold is reached (detrimental
T) the anaerobic metabolism is activated, reducing species fi tness. Beyond the upper tolerance
limit (critical T), the aerobic capacity is null and the individuals are sustained by anaerobic
metabolism and the cells starts to be damaged. Additionally, larger animals are expected
to experience temperature-dependent aerobic metabolism earlier than smaller individuals
(body size effect).
temperature, the fi tness of the individuals starts to decrease and ultimately,
fi sh population experience enhanced mortality of larger animals (Fig. 1).
It is worth noting that critical temperature is well below the temperature
needed for the onset of anaerobic metabolism or for cell damage, thus the
consequences of slightly above normal temperature are expected to yield
low population abundance (Pörtner and Knust 2007).
Body size is another specifi c trait of ectotherms that can be shaped by
temperature (Atkinson 1994). Within a single species, body size tends to
decrease in the warmer region of its geographical distribution (James 1970),
thus, it is expected that climate warming benefi ts the smaller species in
aquatic environments. In fact, Daufresne et al. (2009) compiled data from
several fi sh species in environments that experienced signifi cant warming in
the last 14-27 years, and found that mean body size decreased with gradual
