Julian Sprung's email.

[Don McAllister]

Hi Bill,

Your comments on high temperatures and low oxygen are interesting.  Sounds like it would be worth following
up.  It would seem we know so little of basic biology of coral colonies and their inhabitants.

The high respiration rates are interesting too. Tropical fishes are supposed to be more stenothermal - have
a more limited range of optimal temperatures than boreal fishes. That might combine with low oxygen levels
It would be interesting to see if there will be direct stresses on coral reef fishes as well as through the
loss of habitat.

don
Don McAllister

Billy Causey wrote:

> Ove and others,
>
> I am interested in your comments about the role of oxygen.  For years I have sounded like a broken
> record, exclaiming that while hot water is one of the stressors leading to coral bleaching, that I
> suspect the slick-calm, doldrum weather patterns lead to a drop in dissolved oxygen levels in the coral
> reef environment, especially at night.  I sometimes think we take the level of dissolved oxygen on
> coral reefs for granted .... and tend to not believe there could be a significant enough change to
> affect corals for example.
>
> During years when we have had severe bleaching in the Florida Keys, I have observed reef fish respiring
> very heavily .... in the middle of the day.  So I have often suspected the oxygen levels as being low
> .... during "hot water" events ... even during daylight hours.
>
> Is it possible that the zooxanethellae, existing inside the coral polyp tissue starts competing with