How does rising atmospheric CO2 affect marine organisms?

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First Detection of Human Enteric Viruses in Coral Reefs
Lipp, E.K., Jarrell, J.L., Griffin, D.W., Lukasik, J, Jacukiewicz, J. and Rose, J.B.  2002.  Preliminary evidence for human fecal contamination in corals of the Florida Keys, USA.  Marine Pollution Bulletin 44: 666-670.

In the words of the authors, "corals and reef environments are under increased stress from anthropogenic activities, particularly those in the vicinity of heavily populated areas such as the Florida Keys," where "researchers have noted a loss of diversity in corals and an increase in diseased or damaged corals."  Hence, they set about looking for "microbial indicators of waste and human viruses" that could provide "direct evidence for human impacts on reef environments," concentrating on the area between Long Key and Marathon in the Florida Keys National Marine Sanctuary.

What was done
One-liter samples of surface ocean water were collected from four sites along the transect the scientists studied, while coral surface microlayer (CSM) samples of mucus were obtained from fifteen corals that included Montastraea annularis, Siderastraea radians, Siderastraea sideraea and Solenastraea bournouni.  Several laboratory analyses and tests were then performed on the water and mucus samples in an attempt to find the elusive evidence sought by the scientists.

What was learned
The authors report that "enteroviruses, which specifically indicate contamination with human waste, were detected frequently throughout the CSM samples, while only one water column sample was positive."  Similarly, they note that "Clostridium perfringens was the most prevalent fecal indicator in CSM samples but was never [our italics] recovered from the water column."

What it means
The authors were able to demonstrate that waters showing very little evidence - or even none at all - of human waste contamination may nevertheless be conveying a variety of related noxious substances to the coral reefs that lie beneath their waves.  We hypothesize that the ever-growing stresses these ever-more-prevalent contaminants inflict upon earth's coral reefs make them increasingly more susceptible to increases in maximum water temperature, with the result that they now bleach considerably more readily during periods of unusual warmth than they did in the past, when the more pristine waters that bathed them were less burdened by these contaminants.

Reviewed 24 September 2003