Environmental Engineering Reference
In-Depth Information
such as
Palmaria decipiens
,
Palmaria palmata, Phycodrys austrogeorgica
and
Bangia atropurpurea,
thylakoids form abnormal vesicles upon exposure
to artifi cial UV radiation (Poppe et al. 2002, 2003). UV-induced changes
in the membrane structure of mitochondria were observed in
Palmaria
decipiens
and
Palmaria palmata
. Protein crystals occurring in the cytoplasm
of
Phycodrys
austrogeorgica
showed degradation after UV radiation. These
fi ndings gave fi rst insight into the fi ne structural changes during and after
UV exposure and confi rmed the results on inhibition of the photosynthesis
performance by UV (Poppe et al. 2002, 2003).
Other negative effects of UV radiation especially on macroalgal spores
concern the cytoskeleton. Nuclear division and the activity of the fl agellar
apparatus depend on a functional microtubular system, which might be
damaged by UV. No polarization has been observed in UV exposed zygotes,
they remained spherical and there was no further development. In zygotes
of two species of
Fucus,
actin inhibitors prevented polarization, cross wall
formation and vesicle movement after UV treatment (Schoenwaelder and
Clayton 1999).
Sea level rise
Changes in sea-level are natural phenomena that periodically occur in
geological time of Earth as a consequence of geological and oceanographic
process such as melting of glaciers and ice caps (Church et al. 2001). These
processes have been molding marine and coastal ecosystems as well as the
communities that live in them over thousands of years. There is a general
consensus that this process is today increasing at a signifi cantly faster rate
compared to earlier centuries (Hekstra 1989, Church et al. 2001). The possible
effect of the increase in sea-level on seaweed communities has not been
deeply studied, however it can vary according to the environment they
inhabit and largely depends on the species. The expected consequences of
the increase in sea-level on seaweeds range from changes in the substrate
available for propagules to changes in the distribution limits of entire
communities. While the effect of rising sea level on seaweed begins at
individual and species level, it is expected that the ultimate long-term
consequence would be the change in the spatial distribution and species
composition of assemblages.
Many authors have correlated the vertical distribution of seaweed
with tide levels. In this regard, the sea-level rise is a direct infl uence on the
distribution of seaweeds in the intertidal and subtidal habitat. Predictions
suggest that the increase in sea-level could permanently submerge some
intertidal areas while others could be created, thus changing the mosaic
of seaweed communities along the coast. On the other hand, in shallow
coastal regions, the fl ood of new substrates would increase the availability of
