Julian Sprung's email.

Ove Hoegh-Guldberg oveh at uq.edu.au
Sat Sep 16 18:27:30 EDT 2000


Hi Robyn,

I will be very interested to here as to what you find.
Regarding the greater recovery in the upper portions.  I
take it these are colonies bleached but recovering their
symbiotic dinoflagellates.  I wonder if that is due to the
higher light levels driving a more rapid expansion of
dinoflagellate populations in those areas.

Cheers,

Ove

-----Original Message-----
From: Robyn Cumming [mailto:cumming_r at usp.ac.fj]
Sent: Friday, 15 September 2000 12:08 PM
To: oveh at uq.edu.au; carlson at soest.hawaii.edu;
Billy.Causey at noaa.gov
Cc: coral-list at coral.aoml.noaa.gov
Subject: Re: Julian Sprung's email.


Hi Ove
Your observations on the Stylophoras and Pocilloporas
interest me.  I'm
monitoring recovery of tagged colonies of these and other
species after the
2000 bleaching event in Fiji.  The Stylophoras were the
worst hit - almost
100% mortality. Since I have the dead colonies still tagged
I shall check
them for any living tissue at the bases or undersides of
branches.

I have also noticed that recovery was more rapid on the tops
of colonies,
i.e. some of the Pocillopora verrucosa colonies which
returned to normal
colour on top were in fact still bright white underneath.

Robyn

**************************************************
Robyn Cumming
Lecturer in Ecology
School of Pure and Applied Sciences
The University of the South Pacific
PO Box 1168
Suva
Fiji Islands

ph:   +679 21 2455
fax:  +679 31 5601 or 30 2548

email:  robyn.cumming at usp.ac.fj
web:  http://www.usp.ac.fj/~cumming_r

Visit the Biology web page at:
http://www.usp.ac.fj/biology
****************************************************

----- Original Message -----
From: Ove Hoegh-Guldberg <oveh at uq.edu.au>
To: Bruce Carlson <carlson at soest.hawaii.edu>; Billy Causey
<Billy.Causey at noaa.gov>
Cc: Bernard A. Thomassin <thomassi at com.univ-mrs.fr>;
<coral-list at coral.aoml.noaa.gov>
Sent: Friday, September 15, 2000 11:11 AM
Subject: RE: Julian Sprung's email.


> Dear Bruce,
>
> Very interesting - I am extremely interested in tracking
microclimate
variability as you know.  One
> thing has struck me (and I have a field observation to
back it up) is that
these less stressful
> microclimates may represent reservoirs of coral and
dinoflagellate tissue
for regrowth following
> bleaching events.  After the 1998 bleaching event, we lost
many corals -
Stylophora and Pocillpora
> were hit so hard at One tree Island that students who were
working on
these species had to find
> alternative species to work on.  I was convinced that this
was akin to a
"local extinction event".
> To my surprise, almost the same abundance of large
colonies of these two
species could be found in
> surveys done in 2000 as prior to 1998.  The size of the
heads made it seem
impossible for these
> individuals to be the result of settlement and growth over
18 months.
Where did these coral
> colonies come from? I suspect that the internal areas of
the Stylophora
and Pocillopora coral heads
> survived (lower light) and that the coral heads that I
thought were
completely dead in fact
> regenerated from these living internal regions.  Could the
internal
shading provided by coral heads
> act as a defence against thermal stress?  Interesting
area.
>
> Cheers,
>
> Ove
>
> -----Original Message-----
> From: owner-coral-list at coral.aoml.noaa.gov
> [mailto:owner-coral-list at coral.aoml.noaa.gov]On Behalf Of
Bruce Carlson
> Sent: Monday, 28 August 2000 8:15 AM
> To: oveh at uq.edu.au; Billy Causey
> Cc: Bernard A. Thomassin; coral-list at coral.aoml.noaa.gov
> Subject: Re: Julian Sprung's email.
>
>
> Ove,
>
> Just to add some anecdotal observations I made in Fiji and
Palau that seem
> to be consistent with your hypothesis:  very small
acroporids (better
> surface to volume ratio?), and those in the shade under
larger colonies
were
> the few survivors, and on the Suva barrier reef (where the
water flow is
> strong), one patch of Acropora muricata that I have
monitored since 1972
was
> bleached in April -- or so it appeared on first
inspection.  However, the
> undersides of every branch were brown -- apparently a
shading effect (by
> brown, I mean "normal" in appearance presumably with
zooxanthellae present
> in large numbers).  Temperature, sunlight and water flow
must all have an
> effect.  I recorded this on video tape.  I did not notice
this on any of
the
> bleached corals on the outer barrier reef where mortality
among acroporids
> approached 100%. I will check this colony again in
November to see if it
has
> recovered.
>
> Unrelated to bleaching, the Suva barrier reef has been
overgrown by
> Sargassum since 1972.  I first noticed it growing around
the corals in
1995,
> but this year it has taken over on top of the reef (I have
photos showing
> the progression over the years).  It snags on the Porites
cylindrica and
has
> killed those large old colonies.  The only coral colony
free of the
> Sargassum was "my" old A. muricata colony.  Presumably the
large Stegastes
> sp. damsels in that patch are keeping it clean = a small
oasis in a "sea
of
> Sargassum".  Why is the Sargassum taking over?  My first
guess would be
> increased nutrients over the years from farming, coming
down the nearby
Rewa
> river delta, but over fishing of herbivores may also be a
factor.
>
> Bruce
>
> ----- Original Message -----
> From: Ove Hoegh-Guldberg <oveh at uq.edu.au>
> To: Billy Causey <Billy.Causey at noaa.gov>
> Cc: Bruce Carlson <carlson at soest.hawaii.edu>; Bernard A.
Thomassin
> <thomassi at com.univ-mrs.fr>;
<coral-list at coral.aoml.noaa.gov>
> Sent: Sunday, August 27, 2000 11:13 AM
> Subject: RE: Julian Sprung's email.
>
>
> > Dear Bill,
> >
> > Interesting comments.  My feeling is that oxygen is
involved (either as
an
> promoter of the
> > photoinhibitory production and build-up of active oxygen
within the
> zooxanthellae - that is, as a
> > secondary variable).  We know that thermal stress
collapses oxygen
> production and increases
> > respiration (see papers by Coles and Jokiel: Marine
Biology. 1977;
> 43:209-216, Hoegh-Guldberg and
> > Smith - J. Exp. Mar. Biol. Ecol. 1989; 129:279-303 and
others). If the
> photosynthetic production of
> > oxygen is down and respiration is up (and probably,
bacterial
consumption
> up due to decaying
> > tissue), then oxygen at night over reefs under low flow
(especially on
> reefs where corals dominate)
> > would be expected to decrease, perhaps to critical
levels.  While not a
> primary factor, I would see
> > this as an important follow on effect.  It may actually
be an important
> determinant of mortality.
> >
> > I am interested in following up the aggravating effect
of oxygen - it
> would be useful if oxygen was
> > monitored during the next set of bleaching events.
Perhaps water motion
> (over small patches of
> > reef) might help ameliorate the ultimate impact of a
thermal event.
Just
> a thought.  That and
> > shading a reef might be useful for managers of small
show pieces of
reefs.
> But - just for those
> > journalists our there - this would not be useful for
anything more than
a
> few hundred square metres!
> >
> > Cheers to all,
> >
> > Ove
> >
> > -----Original Message-----
> > From: owner-coral-list at coral.aoml.noaa.gov
> > [mailto:owner-coral-list at coral.aoml.noaa.gov]On Behalf
Of Billy Causey
> > Sent: Monday, 28 August 2000 1:25 AM
> > To: oveh at uq.edu.au
> > Cc: Bruce Carlson; Bernard A. Thomassin;
coral-list at coral.aoml.noaa.gov
> > Subject: Re: Julian Sprung's email.
> >
> >
> > 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
> > the coral polyp for oxygen at night ... when dissolved
oxygen levels are
> low anyway .... and
> > something
> > has to give?  Imagine ... day after day and night after
night, during
> periods of low mixing and
> > natural
> > aeration of surface waters, the oxygen level drops below
a threshold and
> the coral polyp is in a
> > state
> > of competing for oxygen with the zooxanethellae.
> >
> > Folks ... be kind to me!  I am not a coral physiologist,
in fact I
wasn't
> very good in biochemistry
> > .... just a coral reef manager with thousands of hours
of observations
> that make me think the coral
> > bleaching trigger and mechanisms are simpler than we
realize.  I am
> curious about opinions on this
> > idea.
> >
> > Cheers, Billy Causey
> >
> > Ove Hoegh-Guldberg wrote:
> >
> > > Flow probably has some effect through the removal of
some of the
> feedback effects of the high
> > oxygen
> > > tensions that occur during the daylight hours.  If the
increased
> production of active oxygen after
> > > thermal stress (a'la Jones et al 1998, reviewed in
Hoegh-Guldberg
1999),
> then flow might have an
> > > ameliorating effect through the decreased boundary
layer thickness and
> hence oxygen tensions close
> > > to coral surfaces.
> > >
> > > Survival near rivers might be related to the decreased
light stress
due
> to the higher turbidity of
> > > rivers.
> > >
> > > Just some ideas ...
> > >
> > > Cheers,
> > >
> > > Ove
> > >
> > > Professor Ove Hoegh-Guldberg
> > > Director, Centre for Marine Studies
> > > University of Queensland
> > > St Lucia, 4072, QLD
> > >
> > > Director, Heron, Stradborke and Low Isles Research
Stations
> > > President, Australian Coral Reef Society
> > >
> > > Phone:  +61 07 3365 4333
> > > Fax:       +61 07 3365 4755
> > > Email:    oveh at uq.edu.au
> > > http://www.marine.uq.edu.au/ohg/index.htm
> > >
> > > -----Original Message-----
> > > From: owner-coral-list at coral.aoml.noaa.gov
> > > [mailto:owner-coral-list at coral.aoml.noaa.gov]On Behalf
Of Bruce
Carlson
> > > Sent: Saturday, 26 August 2000 4:15 AM
> > > To: Bernard A. Thomassin;
coral-list at coral.aoml.noaa.gov
> > > Subject: Re: Julian Sprung's email.
> > >
> > > Bernard,
> > >
> > > Did you also notice that corals in areas with swift
flowing water
> (usually
> > > from tides) also survived better than nearby reefs
with low flows?  I
> > > noticed this in Fiji on the shallow barrier reef of
the University of
> the
> > > South Pacific, and in Palau near the lighthouse
reef -- both are
similar
> > > reef environments with strong laminar water flow (the
water is shallow
> > > enough to stand up at mid-tide, but the current knocks
you over -- I
> don't
> > > have a more precise current measurement).  Why would
flow rate matter?
> > > Perhaps there is something related to diffusion rates
(which would
> increase
> > > in strong water flow) which offers some protection
during
bleaching????
> If
> > > Ove is right about superoxides forming during warm
water events, maybe
> this
> > > observation is relevant.
> > >
> > > Also, in Fiji, we noticed that reefs near river mouths
also showed
good
> > > survival rates.  The outer barrier reefs in Palau and
Fiji seemed to
be
> hit
> > > the hardest.
> > >
> > > Bruce
> > >
> > > ----- Original Message -----
> > > From: Bernard A. Thomassin <thomassi at com.univ-mrs.fr>
> > > To: <coral-list at coral.aoml.noaa.gov>
> > > Sent: Friday, August 25, 2000 6:30 AM
> > > Subject: Re: Julian Sprung's email.
> > >
> > > >
> > > > Jonathan.Kelsey at noaa.gov wrote :
> > > >
> > > > >-Are these generally accepted concepts?
> > > > >-Can one accurately assess coral mortality rates
associated with a
> > > bleachin
> > > > >event after "a matter of just a few days"?
> > > > >-Are there quantitative studies showing that there
is a greater
> bleaching
> > > > >survival rate among corals in polluted waters
versus those in
> > > non-polluted
> > > > >water? -Any comments and/or further discussion
would be greatly
> > > appreciated.
> > > >
> > > > We will presented a poste about the subject at bali
meeting. In
> Mayotte
> > > > Is., North Mozambique Channel, a huge bleaching
occurred in 1998
> spring
> > > > (end of summer season there) and most of 90 percent
of the shallow
> coral
> > > of
> > > > the barrier reefs died.
> > > > Those corals that surveyed the best are from the
muddy
environnements
> in
> > > > bays, on fringing reef fronts and patches, even the
harbour !why ?
> Because
> > > > the corals living in oceanic cooler waters of the
barrier reef belt
> (170
> > > km
> > > > long) are less adapted to tolerate hot waters and
high level of
light
> > > (some
> > > > got "sun burns" as table acroporas). In opposite
population of
corals
> > > (same
> > > > species) living in neritic coastal waters, in inner
areas of the
> lagoon,
> > > > are genetically more adapted to tolerate : high
temperature, turbid
> waters
> > > > after rainfalls, even falls of salinity. Today in
Mayotte, probably
> the
> > > > recovering ibn coral of the mid-lagoon patch reefs
(recruitement) is
> due
> > > to
> > > > larvae coming from these coastal coral populations.
These is one of
> the
> > > > main reasons to protect these "special" reefs in
muddy environments
> from
> > > > all the effects of coastal works (marinas,
dredgings, infilling of
> > > littoral
> > > > for roads, etc...).
> > > >
> > > > This is a good way for researches.. and from where
larvae that
recruit
> are
> > > > coming.
> > > >
> > > > Bernard A. Thomassin
> > > > Directeur de recherches au C.N.R.S.
> > > >
> > > > G.I.S. "Lag-May"
> > > > (Groupement d'Int=E9r=EAt Scientifique Environnement
marin et
littoral
> de
> > > > Mayotte")
> > > > & Centre d'Oceanologie de Marseille,
> > > > Station Marine d'Endoume,
> > > > rue de la Batterie des Lions,
> > > > 13007 Marseille
> > > > 9l. (33) 04 91 0416 17
> > > > 9l. GSM 06 63 14 91 78
> > > > fax. (33) 04 91 04 16 35 (0 l'attention de...)
> > > > e-mail : thomassi at sme.com.univ-mrs.fr
> > > >
> > > >
> > > >
> >
> > --
> > Billy D. Causey, Superintendent
> > Florida Keys National Marine Sanctuary
> > PO Box 500368
> > Marathon, FL 33050
> > Phone (305) 743.2437, Fax (305) 743.2357
> > http://www.fknms.nos.noaa.gov/
> >
> >
> >
> >
>
>




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