Environmental Engineering Reference
In-Depth Information
and
Temora
longicornis
. This phenomenon caused lower mate encounter
rates since copepods cannot rely on female pheromone plumes (i.e., under
turbulent conditions) and also impaired the ability of males to detect females
pheromone trails, to accurately follow trails and to successfully track a
female. These results indicate that ocean acidifi cation decreases the ability
of male copepods to detect, track and capture a female, hence suggest an
overall impact on population fi tness and dynamics.
Effects on pollutants toxicity.
In addition, acidifi cation may increase the
potential effects of pollutants in marine organisms, especially in coastal
areas. For example, ocean acidifi cation will change the organic and inorganic
speciation of metals and will modify interactions of metals with marine
organisms such as zooplankton. As mentioned above, a consequence of
ocean acidifi cation is a decreased concentration of OH
-
and CO
3
2-
. These
anions form strong complexes in ocean water with divalent and trivalent
metals (Millero et al. 2009). This reduction is expected to change the
speciation of numerous metal ions in seawater (Byrne 2002). Experiments
carried out with two copepods species in laboratory experiments showed
that they were more sensitive to acidity by increasing CO
2
concentration
(Pascal et al. 2010). These authors also found that CO
2
enrichment increased
the free-ion concentration of some metals such as Cu, altering its toxicity,
since free-ion forms of metals are generally more toxic than complex forms.
In addition, the same authors found antagonistic toxicities of CO
2
with Cd,
Cu and Cu free-ion in harpacticoid copepod like
Amphiascoides atopus
and
they concluded that this interaction could be due to a competition for H
+
and metals for binding sites.
Marine zooplankton and UV radiation
The Earth's surface is protected from solar ultraviolet radiation (UV) by
the stratospheric ozone. The anthropogenic emission of chlorofl uorcarbons
(CFCs) has been recognized as the principal factor that produces the
depletion of the ozone layer (Kerr and McElroy 1993). As a consequence of
this decrease of the stratospheric ozone, UV radiation increases its incidence
on the Earth's surface (De Mora et al. 2000).
The ultraviolet spectral region is constituted by wavelengths in the
range of 100-400 nm. Wavelengths range of 280-315 nm corresponds to
UV-B whereas UV-A is defi ned by a range of 315-400 nm. Both wavelengths
ranges are absorbed by O
3
being UV-B more harmful than UV-A to Earth's
surface (Madronich et al. 1995, 1998). UV-B radiation can lead to substantial
biological effects since biological responses to UV-exposure are far greater
at shorter wavelengths (Madronich et al. 1998). Global long-term data
observations on UV-B levels established a signifi cant increase at mid and
