Environmental Engineering Reference
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host-specific endolithic symbionts show turnover with the disappearance of
their host taxa.
Factors that increase bioerosion among heterotrophic endoliths include
increased inorganic nutrient supply, decreased siliciclastic input, and increased
exposure time of the carbonate substrate to the water column. Bioerosion inten-
sity increases in response to modern climate change and anthropogenic impacts,
for example, increasing temperature, alkalinity, eutrophication, rising sea level,
overfishing, intensity of storms, and changing ocean currents. As a destructive
process of the carbonate budget, rates of bioerosion exceed those of reef carbon-
ate production leading to loss of reefal framework.
Whereas fossil reefs have been subjected to changes in seawater temperature
and sea level, the elevated modern rates coupled with overfishing and eutrophi-
cation facilitate bioerosion and diminish carbonate productivity, resulting in net
contraction of reefs. This new paradigm of human influence on the carbonate
budget of reefs is not comparable to historical observations based on the fossil
record and we are entering a new phase in reefal budgets and unchartered
waters.
ACKNOWLEDGMENTS
L. T. thanks P. Copper, E. Edinger, A. A. Ekdale, and M. Wilson for their encouragement
through the years in pursuing the fossil record of endoliths. P. H. would like to thank Dirk
Knaust for an invitation to prepare this review. Michelle Yerman helped in the preparation
of
Fig. 2E
. Edinger provided bioeroded specimens from Puerto Rico.
REFERENCES
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