Fw: Julian Sprung's email.

[Bruce Carlson]

----- Original Message -----
From: Bruce Carlson <carlson at soest.hawaii.edu>
To: <oveh at uq.edu.au>
Sent: Thursday, September 14, 2000 1:22 PM
Subject: Re: Julian Sprung's email.


> Ove,
>
> OK, I'll add a similar note to your observations, but different
> circumstances.  In the Solomon Islands in 1997 (which experienced some
> signficant bleaching effects that year -- a precursor of the big event in
> 1998 everywhere else!), one uninhabited island that we usually visit had
> been hit hard by a hurricane.  I had taken photos of some of the coral
> stands on that island prior to the hurricane (and bleaching -- it was a
> double-whammy).  I was shocked to see the many large Isopora palifera
> colonies all dead.  These were really huge colonies with branches several
> inches in diameter.  All of them throughout the area we visited were
dead --
> or so it seemed.  They are now regrowing quite rapidly covering over the
old
> dead branches.  Apparently little bits of tissue and polyps survive these
> events, either from inside the corallum or just in protected nooks among
the
> branches.  The new growth spreads in a sheet like fashion covering over
the
> old growth.  I suspect in another 5 years many of these colonies will look
> like nothing happened.
>
> Which makes me wonder about the huge Diploastrea and Porites corals that
> appeared to have died in Palau in 1998 and Fiji in 2000.  If they regrow
the
> same way, then they will "come back to life" (like Jokiel's "Phoenix
corals"
> in Kaneohe Bay after the freshwater die-off).  If so, it may be premature
to
> say that any of these really old corals died in 1998 and that the big
> bleaching event was thus the first such event in hundreds of years.  If
this
> has happened in the past, there ought to be markers preserved in the
growth
> rings - but how to recognize them for certain?
>
> Aloha
> Bruce
>
> ----- 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: Thursday, September 14, 2000 1:11 PM
> 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/
> > >
> > >
> > >
> > >
> >
> >
> >
>