How does rising atmospheric CO2 affect marine organisms?

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In Search of Past El Niņos
Brook, G.A., Rafter, M.A., Railsback, L.B., Sheen, S.-W. and Lundberg, J.  1999.  A high-resolution proxy record of rainfall and ENSO since AD 1550 from layering in stalagmites from Anjohibe Cave, Madagascar.  The Holocene 9: 695-705.

What was done
The authors studied the layering of couplets of inclusion-rich calcite over inclusion-free calcite, and darker aragonite over clear aragonite, in two stalagmites from Anjohibe Cave in Madagascar; and they compared their results with historical records of El Niņo events and proxy records of El Niņo events and sea surface temperatures derived from ice core and coral records.

What was learned
The new cave-derived record of El Niņo events compared well with the historical and proxy ice core and coral records, indicating that "the period 1700-50 possibly witnessed the highest frequency of El Niņo events in the last four and a half centuries while the period 1780-1930 was the longest period of consistently high El Niņo occurrences."

What it means
A lot of claims have been made in recent years about how strong and/or frequent El Niņo events have become, as attempts have been made to link their development to global warming.  This research, however, demonstrates that earth's recent El Niņo history has not been at all unusual compared to that of the past four and a half centuries.

Reviewed 1 March 2000