Billy Causey's email on dissolved oxygen
David Blakeway
blakeway at cyllene.uwa.edu.au
Mon Aug 28 02:38:57 EDT 2000
Hello coral-listers,
I believe Billy could be right in considering dissolved oxygen depletion to be a
cause of some coral bleaching and mortality. I attributed bleaching and
mortality of Acropora and Montipora spp. at some of my PhD sites in the Houtman
Abrolhos Islands, Western Australia to oxygen depletion. The sites are deep (10
to 30m) depressions in the reef. DO concentrations below 1 mg/L in some
instances. Transplanted Acropora branches bleached and died within a week at
DO's of 2 to 4 mg. Handling controls suffered no (visible) ill effects. I can't
be sure that oxygen depletion was responsible, as other variables were
uncontrolled. Water temperature was only 24 deg C though. Is anybody doing any
controlled field or lab experiments?
I still feel that temperature is critical in many cases. I have a Hydnophora
pilosa colony in an aquarium that bleaches as soon as water temperature exceeds
28 deg C, but recovers at lower temperatures. The aquarium has strong
circulation, so the colony ?should be getting plenty of oxygen.
Dave
David Blakeway
Institute for Regional Development
University of Western Australia
Nedlands WA 6907
Australia
More information about the Coral-list-old
mailing list