FW: Dust and Disease on the Great Barrier reef

Wed Oct 30 11:29:02 EST 2002

Hi Julian and others:

We have come across a small flatworm in our aquaria that we suspect of
having eaten many of our juvenile corals.  They are only a mm or so in
length and would not be noticeable to the un-aided eye of a diver.  We found
them with high quality dissecting scopes.  They are full of zooxanthellae,
and we found them crawling over our settlement plates with empty coral spat
calices.  We've also seem nematodes feeding on coral tissues.  There are a
lot of microscopic things out there killing corals, it appears!   If any of
you know what some of these tiny critters are, I'd appreciate help in IDing
them.  I do have some photographs.

Alina Szmant

At 08:38 AM 10/30/02 -0500, Julian Sprung wrote:

> Thanks for the article and links Gene. For what its worth, white
> syndrome-like outbreaks in Acropora in aquariums are often associated with
> pathogenic bacteria, and their occurrence and rate of damage is affected
> by
> temperature (high temps promote them).
>
> Slow-progressing bottom-up tissue loss is sometimes not caused by disease
> but by predators instead. Reasearchers who study Caribbean Acropora are
> familiar with the coral eating snails Coralliophila, whose affect on the
> corals is often mistaken by casual observers for disease. In aquariums
> with
> Indo-Pacific Acropora there are occasionally similar snails such as
> Drupella, which fortunately don't reproduce and can be removed fairly
> easily. There are also nudibranchs such as Cuthona that leave dead white
> patches on coral, but these affect mainly Montipora and Porites.
>
> There is one predator of Indo-Pacific corals in aquariums (and presumably
> in
> the wild too) that often goes unnoticed, though its affect can be
> dramatic.
> The beast is Scutus cf. unguis, a black limpet that I'm sure occurs on the
> Great Barrier Reef. These limpets are active at night only and do not stay
> near the coral during the day, so researchers diving during the day
> wouldn't
> ever associate it with the dying coral. In aquariums Scutus has the
> unfortunate habit of reproducing prolifically, so its effect can blossom,
> and result in the loss of all small polyped corals.
>
> I mention this here because the comment in the article, "it takes months
> to
> kill a large colony" sounds like it may be a predator. It may also be a
> disease, but the researchers involved should check the corals at night
> just
> to rule out Scutus.
>
> Sincerely,
>
> Julian Sprung
> ----------
> >From: Gene Shinn <eshinn at usgs.gov>
> >To: coral-list at aoml.noaa.gov
> >Subject: Dust and Disease on the Great Barrier reef
> >Date: Fri, Oct 25, 2002, 9:09 AM
> >
>
> > Is everyone watching what is happening in Australia as we speak? Check
> > out
> > these images and read the press releases. Note the statement, "White
> > Syndrome outbreaks are happening in pristine areas of the Great Barrier
> > Reef, the AIMS teams says, on outer reefs untouched by coastal
> > development
> > and tourism. This means the reef diseases are not linked to pollution,
> > as
> > are other coral diseases around the world."
> >
> > Gene
> >
> >
> h
> tp://www.nrlmry.navy.mil/aerosol/satellite/seawifs/australia/200210/200210
> 2300_aust
> > ralia.jpg
> >
> >
> h
> tp://rapidfire.sci.gsfc.nasa.gov/gallery/?2002296-1023/Australia2.A2002296
> .2355.1km
> > .jpgIs
> >
> >
> h
> tp://rapidfire.sci.gsfc.nasa.gov/gallery/?2002296-1023/Australia2.A2002296
> .2355.1km
> > .jpg
> >
> > http://www.news.com.au/common/story_page/0,4057,5357841%255E1702,00.html
> >
> > http://news.com.au/common/story_page/0,4057,5357418%255E1702,00.html
> >
> >>CORAL REEF KILLS, UNKNOWN ETIOLOGY - AUSTRALIA
> >
> >>------------------
> >>Scientists at the Australian Institute of Marine Science (AIMS) have
> >>confirmed the existence of coral disease on the world's longest reef,
> >>the Great Barrier Reef, which stretches along Australia's east coast.
> >>
> >>Researchers at the government institute do not have to travel far to
> >>see the giant reef (they just glance out their front door) but they
> >>have searched the world for a clue to the cause of the disease they
> >>have observed.  AIMS scientists working in the long-term monitoring
> >>program say the disease they have documented is in a broad category
> >>known as White Syndrome. Soon they hope to learn exactly what White
> >>Syndrome is.
> >>
> >>Cathie Page, a deep ocean ecologist on the AIMS long term monitoring
> >>team, says, "It's more common on table corals. It starts at the base
> >>and works its way up. The disease breaks the coral tissue down,
> >>eventually killing it."
> >>
> >>"It doesn't fit the description of diseases found anywhere else in
> >>the world, so it might be specific to the Pacific," she says.  In the
> >>3 years Page has been on the monitoring team, she has logged about
> >>450 dives spanning 48 reefs.  She has seen White Syndrome kill at
> >>varying rates.
> >>
> >>"It could kill a colony of 2 metres (6.5 feet) in diameter in 2 weeks
> >>but in some other cases, it takes months to kill a large colony," she
> >>said.
> >>
> >>The first record of coral diseases came from reefs off Belize and
> >>Florida in 1973. In 1993 coral diseases were noticed on the Great
> >>Barrier Reef. When the diseases worsened in the late 1990s, the
> >>long-term monitoring team started documenting their activity.  In
> >>1999 only 7 reefs were  infected with White Syndrome; in 2002 33
> >>reefs were affected out of the 48 studied by the AIMS long-term
> >>monitoring team.
> >>
> >>The highest number of infected colonies within one reef was 101 in a
> >>1500-square-meter area. That was on Carter Reef, an outer shelf reef
> >>in the Cooktown/Lizard Island sector. The syndrome killed those
> >>colonies infected and caused a decline in hard coral cover on this
> >>reef.
> >>
> >>AIMS scientists together with researchers from James Cook University
> >>who are collaborating on the project have recorded the disease in
> >>northern waters during the winter months.  Outer-shelf reefs near
> >>Lizard Island off Cooktown in the northern Great Barrier Reef and the
> >>Capricorn Bunker reefs in the southern Great Barrier Reef are the
> >>worst affected areas.
> >>
> >>White Syndrome outbreaks are happening in pristine areas of the Great
> >>Barrier Reef, the AIMS teams says, on outer reefs untouched by
> >>coastal development and tourism. This means the reef diseases are not
> >>linked to pollution, as are other coral diseases around the world.
> >>Coral bleaching is also affecting the great reef, and scientists fear
> >>White Syndrome could be spreading more quickly in corals weakened by
> >>bleaching.
> >>
> >>Coral bleaching is the name given to an event in which coral expel
> >>their symbiotic algae due to extreme stress, such as unusually hot
> >>water, according to AIMS bleaching expert Dr. Terry Done.
> >>
> >>The bleached corals die if the stress is extreme or prolonged.  With
> >>rising water temperatures over the tropical summers, coral bleaching
> >>events are more widespread and happening more often, leaving little
> >>time for coral to recover.
> >>
> >>"Bleached coral is not healthy and potentially more susceptible to
> >>diseases," said Page. "We don't know  what's causing this disease.
> >>It's microscopic; it could be a range of things."
> >>
> >>AIMS has sent samples of corals affected by White Syndrome away for
> >>testing. When the results come back, AIMS will search for solutions
> >>that might save the corals of the Great Bar
> >
> > ------------------------------------ -----------------------------------
> >
> > http://coastal.er.usgs.gov/african_dust/
> > |
> > E. A. Shinn
> > email  eshinn at usgs.gov
> > USGS Center for Coastal Geology     |
> > 600 4th St. South                   | voice  (727) 803-8747 x3030
> > St.Petersburg, FL  33701            | fax    (727) 803-2032
> > ------------------------------------ -----------------------------------
> >
> >
> >
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*******************************************************************
Dr. Alina M. Szmant
Coral Reef Research Group
Professor of Biology
Center for Marine Science
University of North Carolina at Wilmington
5600  Marvin K. Moss Lane
Wilmington  NC  28409-5928
tel:  (910)962-2362  fax:  (910)962-2410
email:  szmanta at uncwil.edu
http://www.uncwil.edu/people/szmanta/
******************************************************************