Geoscience Reference
In-Depth Information
[CAM 11] reported the development of a technique for modifying the
pH in submerged coastal benthic communities by using open-top
transparent chambers. Other systems have been developed, initially for
deep-sea environments [KIR 09]. They have recently been adapted
and used on a coral reef (Figure 5.11, [KLI 12]) and on marine plant
communities [ARN 12]. Other systems are in development, which will
allow, in the short term, for the studying of a significant number of
marine communities and regions.
Another major obstacle for predicting the effects of future
environmental changes, including ocean acidification, is the lack of
knowledge on the potential for acclimation and adaptation. The vast
majority of experiments carried out to date have never exceeded a few
months in length. Yet, organisms such as mollusks and sea urchins
can live for several years, and have lifecycles comprising planktonic
larval stages and benthic adults. A very limited number of studies
have involved the links between these life stages as well as the links
existing between two successive generations. The study by Parker
et al.
[PAR 12] is very interesting as it is one of the few which shows
that breeders are capable of bestowing a certain plasticity to their
descendants, even if they have themselves been raised in suboptimal
environmental conditions. It is crucial that similar studies are
performed, and that the use of molecular tools (e.g. [HAM 12])
becomes more widespread.
Finally, as mentioned above, very few studies have focused on the
effects of multiple simultaneous perturbations. The ocean will
be subject to at least three global perturbations, all linked to the
increase in greenhouse gases, such as CO
2
. Like ocean acidification,
the warming of seawater (0.7°C over the last 100 years and 3°C or
more between now and 2100) is an unavoidable reality. The ocean's
deoxygenation corresponds to the loss of dissolved oxygen resulting
directly and indirectly from global warming, as well as the massive
delivery of organic matter that has led to local eutrophication. By
2100, the ocean could lose 1-7% of its global supply of oxygen
[KEE 10]. Unfortunately, very few studies have involved the combined
effects of these environmental modifications. Yet, as we saw earlier,
the effects of acidification can be exacerbated at high temperatures
