How Corals Succumb to Sedimentation Weber, M., de Beer, D.,
Lott, C., Polerecky, L., Kohls, K. Abed, R.M.M., Ferdelman, T.G.
and Fabricius, K.E. 2012. Mechanisms of damage to corals exposed
to sedimentation. Proceedings of the National Academy of
Sciences USA 109: 10.1073/pnas.1100715109. In an effort to find
the true mechanisms of death by sedimentation, Weber et al. made
numerous microsensor measurements in mesocosm experiments and in
naturally accumulated sediment on corals. And what did they
learn? The eight researchers - hailing from Australia, Germany,
Italy and Oman - found that (1) in organic-rich sediments, pH
and oxygen started to decrease as soon as the sediment
accumulated on the coral, that (2) "the combination of anoxia
and low pH led to colony death within 24 hours," and that (3)
"when hydrogen sulfide was added after 12 hours of anoxia and
low pH, colonies died after an additional three hours." And
based on these observations, they suggest that (4)
"sedimentation kills corals through microbial