Publisher :
Place of publication :
Publication year : 0
Thematic : Coral Reef
Language : English
Note
Coral growth rate can be affected by environmental
parameters such as seawater temperature, depth,
and light intensity. The natural reef environment is also
disturbed by human influences such as anthropogenic
pollutants, which in Barbados are released close to the
reefs. Here we describe a relatively new method of
assessing the history of pollution and explain how these
effects have influenced the coral communities off the
west coast of Barbados. We evaluate the relative impact
of both anthropogenic pollutants and natural stresses.
Sclerochronology documents framework and skeletal
growth rate and records pollution history (recorded as
reduced growth) for a suite of sampled Montastraea
annularis coral cores. X-radiography shows annual
growth band patterns of the corals extending back over
several decades and indicates significantly lower growth
rate in polluted sites. Results using laser-ablation
inductively coupled plasma mass spectrometry
(LA-ICP-MS) on the whole sample (aragonite, organic
matter, trapped particulate matter, etc.), have shown
contrasting concentrations of the trace elements (Cu, Sn,
Zn, and Pb) between corals at different locations and
within a single coral. Deepwater corals 7 km apart,
record different levels of Pb and Sn, suggesting that a
current transported the metal pollution in the water. In
addition, the 1995 hurricanes are associated with
anomalous values for Sn and Cu from most sites. These
are believed to result from dispersion of nearshore polluted
water. We compared the concentrations of trace
elements in the coral growth of particular years to those
in the relevant contemporaneous seawater. Mean values
for the concentration factor in the coral, relative to the
water, ranged from 10 for Cu and Ni to 2.4 and 0.7 for
Cd and Zn, respectively. Although the uncertainties are
large (60–80%), the coral record enabled us to demonstrate
the possibility of calculating a history of seawater
pollution for these elements from the 1940s to 1997. Our
values were much higher than those obtained from
analysis of carefully cleaned coral aragonite; they demonstrate
the incorporation of more contamination
including that from particulate material as well as
dissolved metals.
Go to source
Keywords : Hipposideros grandis
Encoded by : Pauline Carmel Joy Eje
