> form (urea).  There have been studies in which schools of juvenile grunts
> appear to purposefully defecate near the coral heads they use as shelter
> (unlike most terrestrial aminals which usually make the effort to defecate
> as far as possible from their preferred hang-outs unless marking
> territory).  This has been interpreted as an important part of the process
> by which the zooxanthellae (endosymbiotic algae living in the coral tissue,
> for anyone who is not a coral reef person or a fan of big words) get enough
> nutrients (can't remember the ref for this).  Even if protein is
>

Meyer, J.L., E.T. Schultz and G.S. Helfman.  1983.  Fish schools: an
asset to corals.  Science 220: 1047-1049.

The research actually doesn't refer to grunts 'purposefully
defecating'.  Grunts use coral heads as shelter sites during the day,
so their excreta are naturally in the vicinity of the coral.  The
coral uptake dynamics are rapid, so that localized enrichments of
ammonia can benefit the coral tissue and zooxanthellae.  One other
small correction here: it is the soluble excreta, rather than the
solid feces, that have the effect on coral tissue.
       / ///
 _* )=>=======<<
  )    `  \\
Eric Schultz

web page:
HTTP://WWW.EEB.UCONN.EDU

fish class home page:
http://www.eeb.uconn.edu/EEB200/intropage.htm

Department of Ecology and Evolutionary Biology
75 N. Eagleville Rd.
University of Connecticut
Storrs CT 06269-3042
Phone (860) 486-4692
Fax (860) 486-6364

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