A new study suggests that some coral reefs could be protected from bleaching by a natural ‘ocean thermostat’ that regulates sea surface temperatures in the western pacific warm pool.
The paper was published in GRL on 9th February:
GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L03613, doi:10.1029/2007GL032257, 2008
Joan A. Kleypas, National Center for Atmospheric Research, Boulder, Colorado, USA
Gokhan Danabasoglu, National Center for Atmospheric Research, Boulder, Colorado, USA
Janice M. Lough, Australian Institute of Marine Science, Townsville, Queensland, Australia
Several negative feedback mechanisms have been proposed by others to explain the stability of maximum sea surface temperature (SST) in the western Pacific warm pool (WPWP). If these “ocean thermostat” mechanisms effectively suppress warming in the future, then coral reefs in this region should be less exposed to conditions that favor coral reef bleaching. In this study we look for regional differences in reef exposure and sensitivity to increasing SSTs by comparing reported coral reef bleaching events with observed and modeled SSTs of the last fifty years. Coral reefs within or near the WPWP have had fewer reported bleaching events relative to reefs in other regions. Analysis of SST data indicate that the warmest parts of the WPWP have warmed less than elsewhere in the tropical oceans, which supports the existence of thermostat mechanisms that act to depress warming beyond certain temperature thresholds.
The study is also reported on the BBC website: ‘Ocean thermostat can save coral’
Jen reminded me about the OLO article by Peter Ridd: ‘The Great Great Barrier Reef Swindle’
“The scientific evidence about the effect of rising water temperatures on corals is very encouraging. In the GBR, growth rates of corals have been shown to be increasing over the last 100 years, at a time when water temperatures have risen. This is not surprising as the highest growth rates for corals are found in warmer waters. Further, all the species of corals we have in the GBR are also found in the islands, such as PNG, to our north where the water temperatures are considerably hotter than in the GBR. Despite the bleaching events of 1998 and 2002, most of the corals of the GBR did not bleach and of those that did, most have fully recovered.
Of course, some corals on the Queensland coast are regularly stressed from heat, viz. the remarkable corals of Moreton Bay near Brisbane which are stressed by lack of heat in winter. A couple of degrees of global warming
would make them grow much better.”