Deep skeletal refugia for zoox

[Andrew Baker]

Hi Bob

Just a quickie to follow up on your questions. I hope it is still 
appropriate to keep this discussion on the public list.

Yes, there is certainly scope for the idea that internal microhabitats 
might provide refugia for zoox taxa that are outcompeted at the surface 
under normal environmental conditions. Rob (Rowan) had some ideas related 
to this (when I first met him back in 1995) - specifically, that the outer 
tips of polyps might contain "sun-loving" zoox, while the deeper tissue 
between polyps might contain "shade tolerant" zoox - but the idea could be 
extended (literally!) into the skeleton itself, which I agree would be a 
very interesting project. As far as I know, no-one has studied this kind of 
small scale "zonation", and/or its relation to the Phoenix effect. It would 
be technically challenging - either by careful extraction from 
tissue/skeleton preparations (probably a somewhat haphazard approach), or 
by some kind of in situ hybridization protocol (a much better way of 
demonstrating spatial differentiation, and what Rob had intended to do back 
in 95). I'd love to hear from anyone who has attempted this.

I've done some survey work looking at undersides of colonies (e.g. flipping 
over fungiids to find out what they have there), but never any deep 
skeleton stuff. I didn't find any striking differences (by that I mean 
weird or unusual zoox), but I did occasionally find "low light" zoox taxa 
similar to the story from Rowan et al 1997 in Nature. My guess is a drill 
press with a masonry grinder bit to produce a homogenate of tissue and 
skeleton might be the way to go (!a trip to the hardware store!), or 
sectioning followed by in situ hybridization. I'd ask Rob if he's ever 
attempted this, although I don't think he has.

All of the protocols I'm aware of that people are using now for zoox 
extraction and ID would miss these refugia.

Yes, there are a couple of places I would like to study zoox repopulation 
following bleaching. My main project with regards to this (with Peter 
Glynn) is looking at zoox repopulation in communities of reef corals in 
Panama and the Galapagos. These communities showed quite high incidences of 
bleaching, but not as much mortality as we might have expected (contact 
Peter for more details). I have tagged colonies in both areas that we can 
re-sample to see how zoox communities changed. These tagged colonies 
include some colonies that were extremely bleached and other adjacent 
colonies (of the same species) which appeared entirely unaffected (and - 
yes - its because they appear to have contained different zoox). But we 
don't know yet how many of the tagged colonies survived, or what zoox they 
have now if they did. We'll find out in the spring, although (with the 
intervening time period) interpretation might be difficult (but it usually 
is anyway...!)

Finally - yes, you're right about collaborations between aquarists and 
researchers. The project you referred to by LeRoy Headlee is actually a 
collaboration he and I have to look at how zoox taxa change in the aquarium 
environment (small world, huh?). LeRoy has some interesting ideas on how to 
encourage rapid switching of symbionts in "captivity", and we are going to 
investigate them to see if they work. The research was funded by the 
American Zoo and Aquarium Association, with some matching support from GARF 
(LeRoy). You're right, I think it could be very interesting stuff. I will 
keep you posted, and hopefully tell you more in Bali.

Andrew


>Date: Sat, 16 Sep 2000 08:28:17 -0500
>From: "Robert W. Buddemeier" <buddrw at kgs.ukans.edu>
>
>Right -- to the extent that different taxa of zoox inhabit coral tissue,
>there could be a strong differentiation between those found in the
>internal microhabitats.  Repopulation of the skeletal structure from
>these survivors woiuld be a different/alternative mechanism -- and a
>much more reliable one -- compared to repopulating bleached but living
>corals with a different zoox strain by external infection or internal 
>competititon.
>
>Such low-light refugia might well be missed by a standard approach to
>coral tissue sampling (e.g., for zoox ID), and in any case might have
>quite low populations of zoox.
>
>Some research oriented questions --
>1. Has anybody done zoox population studies at any of the sites now
>characterized by rapid recovery after apparent mortality? (Andrew?
>Rob?)  If so, a revisit would be in order -- that could be the sort of
>thing an NSF SGER award could be sought for.
>
>2. Who can evaluate whether their (or anybody's) protocol for sampling
>zoox for ID would, might, or would not miss possible refugia (deep in
>skeleton, undersides of colonies, etc.)?
>
>3. Now that there are good indications of taxa and locations where such
>refugia might exist, a systematic search would seem to be in order.
>
>4. The aquarium and farming observations are important and
>underexploited sources of information.  For example, LeRoy Headlee's
>recent response to David Zakai said, in part, "Very low priced adult
>corals are not as hardy as domesticated corals,
>we have funded a research project to learn the best way to accomplish
>much faster the changes that happen to the corals symbiotic colonies
>as they are domesticated. After the coral strains have been in
>captivity for several semesters they become able to tolerate high
>temperatures that often kill the same strain when it is freshly
>imported."  -- Seems to me that some collaborative research on the
>mechanisms of that empirically observed change could have a very big
>pay-off.
>
>Bob Buddemeier


__________________
Andrew C. Baker, Ph.D.
Wildlife Conservation Society
Founded in 1895 as the New York Zoological Society