Environmental Engineering Reference
In-Depth Information
Fig. 3. Schematic diagram of the possible consequences of climate change on seaweed benthic
communities.
is causing serious concern for permanent changes in habitat structure
and loss of seaweed habitats. Moreover, not only the biodiversity of
the algae themselves is under threat, they are foundation species which
provide and modify resources available to other organisms both in terms
of environmental conditions, habitat structure and food. Because of their
central role, changes in seaweed population are likely to affect associated
species populations and the ecological function of the entire ecosystem.
UV radiation is usually known to harm physiological process in
macroalgae. During their long history of evolution, seaweeds have
developed protective strategies against harmful UV irradiances, such as
synthesizing and accumulating UVAC and the repair of DNA damage.
Different life stages of seaweeds show different sensitivity to solar UV
radiation, with less-differentiated forms being more sensitive. Species
distributed at different depths in the intertidal zone also show different
responses to solar UVR; upper species, that are usually exposed to higher
levels of solar radiation and accumulate higher contents of UVAC (such as
MAAs) are more tolerant of UVR.
Ocean acidifi cation as a consequence of high levels of CO 2 in seawater
could affect seaweed populations and communities in different aspects, and
seaweed responses are highly variable. The main effects at organismic level
would include increased photosynthesis and growth rates and disruption
of the calcifi cation processes in calcifi ed seaweeds. Among the effects of
ocean acidifi cation at community level, the most important include changes
in interaction processes between corals and seaweeds leading to states of
seaweed dominance. It is expected that the responses of seaweeds to reduced
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