[Coral-List] Preparing for Bleaching in the Caribbean
Esther Peters
estherpeters at verizon.net
Mon Sep 27 13:00:24 EDT 2010
Thank you, Doug and Judy, for noting that yes, both
bleaching-associated disease outbreaks and mortalities of bleached
organisms can occur.
It is important to remember that for the tropical reef organisms having
symbioses with unicellular dinoflagellates or other algae, the sign of
bleaching (loss of the algae or the algal pigments) means that the
host's health is compromised in some way. This is because the algae are
unable to provide the nutritional and waste removal functions that
enable to animal to thrive when they are present and able to
photosynthesize.
Microscopical examinations of bleached tissues indicate the loss of the
algae may have occurred not only by exocytosis of the algae (so that few
or none remain in intact host cells), but by mortality of the algae
within the cell, by replacement of the algae with a parasite (as in the
case of coccidia), or by complete sloughing of the gastrodermal cells
from intact mesoglea and epidermis (in corals). These different modes
can mean different outcomes for the coral host. Intact coral host cells
may be recolonized by the algae, but in other cases (particularly
gastrodermal cell sloughing) the host tissue will eventually be lost
from the skeleton and noticed as mortality. This tissue loss may or may
not conform to a pattern of tissue loss that has been recognized as a
"coral disease" (e.g., white plague, white patch disease, white band
disease).
While the zooxanthellae are absent from the cells, the host may be able
to survive quite well through other nutritional resources. However, the
functioning of the host's defense/immune mechanisms (e.g., mucus
production, phagocytosis, production of lysozymes) may be suboptimal,
and could result in cellular lysis or necrosis, perhaps the result of
infection by a pathogenic microorganism or microbial consortium, such as
black band disease. But, perhaps not, as not all cases of mortality are
due to infectious agents! Preparation of tissue samples for
histopathological examination with light or electron microscopy is
really necessary to help determine the actual cause of bleaching and
whether the host's cells have reversible or irreversible injuries that
may result in different outcomes. And the state of the host's health can
change over time, too, meaning that multiple samples might need to be
examined while the host is bleached to know whether it might recover or not.
But, as Judy points out, gross observations made through standardized
protocols by trained surveyors are very necessary, too, and are always
our first step in recognizing adverse changes occurring on our reefs!
Esther Peters
George Mason University
On 9/25/2010 1:31 PM, Judith Lang wrote:
> Hi Doug,
> Thank you for reminding us of the importance of bleaching-associated
> disease outbreaks. Given what happened after the 1998 and 2005 mass-
> bleaching events (e.g., Kramer, 2003; Miller et al., 2009), the
> possibility that this could occur again in the wider Caribbean is a
> major concern. But corals here have also died after having been
> severely bleached without showing any visible signs of disease
> (Oxenford, H.A. et al., 2009).
>
> If responses to the 2005 severe bleaching event are any guide to the
> future, researchers in the affected areas will either intensify their
> own monitoring efforts or initiate BLAGGRA Belt Transect surveys. Rest
> assured they will describe any subsequent outbreaks of disease or
> other kinds of post-bleaching mortality. As you know, surveys like
> these are labour-intensive and, to be credible, must be carried out by
> experienced surveyors–which unfortunately limits how many sites can be
> assessed and, hence, the generality of any findings.
>
> The BLAGRRA Line Transect protocol complements detailed monitoring
> efforts with quickly obtained data on the cumulative effects of all
> causes of death in all species of corals. We hope it would be used to
> capture the spatial extent of bleaching (and any direct bleaching
> mortality) at representative sites in addition to those of local
> strategic importance (like MPAs); facilitate the continuation of
> surveys after the initial excitement induced by the bleaching event
> has passed but corals are in danger of succumbing to some form of post-
> bleaching mortality; and simplify subsequent regional comparisons
> (e.g., Eakin et al., in press).
>
> Providing they know what healthy corals should look like in their
> area, rangers, marine biology students, recreational divers, etc., can
> easily be taught to use the line transect protocol because it isn't
> necessary to be proficient at identifying species or in distinguishing
> the signs of diverse coral diseases versus predators and other sources
> of mortality. (However, space is available on the data sheets for more
> knowledgeable surveyors to name the corals which are most affected, or
> any coral diseases, along with other kinds of bleached or diseased
> organisms, such as zoanthids, soft corals and sponges.)
>
> In my original posting I forgot to remind all those who are worried
> about the likelihood of bleaching on their reefs to examine NOAA's
> most recent degree heating week chart for their specific geographic
> area (these are available at www.osdpd.noaa.gov/ml/ocean/cb/dhw.html).
>
> Note also that the line transect protocol should be adaptable for use
> on Indo-Pacific reefs.
>
> Best regards,
> Judy
>
> References
> Eakin, M. and 66 others. In press. Caribbean corals in crisis: record
> thermal stress, bleaching, and mortality in 2005. PLoS ONE.
>
> Kramer, P.A. 2003. Synthesis of coral reef health indicators for the
> western Atlantic: results of the AGRRA program (1997-2000). Atoll Res.
> Bull. 496:1-55.
>
> Miller, J., E. Muller, C. Rogers, R. Warra, A. Atkinson, K.R.T.
> Whelan, M. Patterson, B. Witcher. 2009. Coral disease following
> massive bleaching in 2005 casues 60% decline in coral cover on reefs
> in the US Virgin Islands. Coral Reefs 28:925-937.
>
> Oxenford, H.A., R. Roach and A. Braithwaite. 2009. Large scale coral
> mortality in Barbados: a delayed response to the 2005 bleaching
> episode. Proc. 11th Int. Coral Reef Symp. 505-509.
>
> ******************************************
> On Sep 24, 2010, at 11:57 PM, Douglas Fenner wrote:
>
>> Since coral disease outbreaks have been reported following some
>> bleaching events, I'd suggest people keep disease in mind for
>> monitoring as well, if a bleaching event develops in their area.
>> The diseases can cause a significant proportion of the total
>> mortality. Doug
>>
>> News from “Science Now”: “Record Hot Summer Wrecks Havoc.”
>>
>> Science Now reports that NASA says this year so far is the hottest
>> on record in the 131 years of record keeping. Nearly 0.7 C hotter
>> than the average from 1951 to 1980, and NOAA has found essentially
>> the same thing using different data. Nightime temperatures hit
>> record highs in 37 states of the US this summer. The National Snow
>> and Ice Data Center in Boulder, Colorado, has found near-record ice
>> area loss so far this year in the Arctic Ocean, and expects the area
>> to hit a record low this year. Ice volume is at a record low,
>> 10,000 cubic kilometers lower than the average of the last 30
>> years. Ice volume is being lost at 17% per decade. The open sea
>> surface absorbs much more light energy than the white ice, trapping
>> more heat.
>>
>> http://news.sciencemag.org/sciencenow/2010/09/record-hot-summer-wreaks-havoc.html?etoc=&sms_ss=email
>> ----- Original Message ----- From: "Judith Lang"<jlang at riposi.net>
>> To:<coral-list at coral.aoml.noaa.gov>
>> Sent: Tuesday, September 21, 2010 12:37 AM
>> Subject: [Coral-List] Preparing for Bleaching in the Caribbean
>>
>>
>> Fellow Coral Reef Enthusiasts,
>>
>> We certainly hope not, but should current predictions for parts of the
>> Caribbean come to pass, the vital signs of affected corals should be
>> followed like those of heart attack victims because the long-term
>> impacts of having been severely bleached can be of greater
>> significance than the initial trauma.
>>
>> We invite regional divers to join us in monitoring simple, ecosystem-
>> level pigmentation changes in live corals and any associated changes
>> in live coral cover using the newly updated BLAGGRA Line Transects
>> protocol (www.agrra.org/BLAGRRA). Sites can be very quickly and
>> repeatedly surveyed by small teams of 1-2 experienced divers. A
>> representative assessment can be made of reefs in the area affected by
>> bleaching, and/or sampling can be focused on special-interest sites
>> (such as within and outside of MPAs).
>>
>> Try to start the surveys before bleaching begins (if possible).
>> Resurvey whenever bleaching occurs, and at intervals during any
>> subsequent period of delayed mortality or recovery until conditions
>> return to “normal.”
>>
>> To assess coral conditions at the population level, with species- and
>> size- specific, information, see the companion BLAGGRA Belt Transects
>> protocol (www.agrra.org/BLAGRRA).
>>
>> Data submitted to the AGRRA project will be processed, summarized,
>> and speedily posted online at the AGRRA website.
>>
>> Please help us create a regionally consistent and comparable
>> database for everyone to use.
>>
>> Judy Lang
>> For the AGRRA Organizing Committee
>> _______________________________________________
>> Coral-List mailing list
>> Coral-List at coral.aoml.noaa.gov
>> http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
> On Sep 24, 2010, at 11:57 PM, Douglas Fenner wrote:
>
>> Since coral disease outbreaks have been reported following some
>> bleaching events, I'd suggest people keep disease in mind for
>> monitoring as well, if a bleaching event develops in their area.
>> The diseases can cause a significant proportion of the total
>> mortality. Doug
>>
>> News from “Science Now”: “Record Hot Summer Wrecks Havoc.”
>>
>> Science Now reports that NASA says this year so far is the hottest
>> on record in the 131 years of record keeping. Nearly 0.7 C hotter
>> than the average from 1951 to 1980, and NOAA has found essentially
>> the same thing using different data. Nightime temperatures hit
>> record highs in 37 states of the US this summer. The National Snow
>> and Ice Data Center in Boulder, Colorado, has found near-record ice
>> area loss so far this year in the Arctic Ocean, and expects the area
>> to hit a record low this year. Ice volume is at a record low,
>> 10,000 cubic kilometers lower than the average of the last 30
>> years. Ice volume is being lost at 17% per decade. The open sea
>> surface absorbs much more light energy than the white ice, trapping
>> more heat.
>>
>> http://news.sciencemag.org/sciencenow/2010/09/record-hot-summer-wreaks-havoc.html?etoc=&sms_ss=email
>>
>>
>>
>> ----- Original Message ----- From: "Judith Lang"<jlang at riposi.net>
>> To:<coral-list at coral.aoml.noaa.gov>
>> Sent: Tuesday, September 21, 2010 12:37 AM
>> Subject: [Coral-List] Preparing for Bleaching in the Caribbean
>>
>>
>> Fellow Coral Reef Enthusiasts,
>>
>> We certainly hope not, but should current predictions for parts of the
>> Caribbean come to pass, the vital signs of affected corals should be
>> followed like those of heart attack victims because the long-term
>> impacts of having been severely bleached can be of greater
>> significance than the initial trauma.
>>
>> We invite regional divers to join us in monitoring simple, ecosystem-
>> level pigmentation changes in live corals and any associated changes
>> in live coral cover using the newly updated BLAGGRA Line Transects
>> protocol (www.agrra.org/BLAGRRA). Sites can be very quickly and
>> repeatedly surveyed by small teams of 1-2 experienced divers. A
>> representative assessment can be made of reefs in the area affected by
>> bleaching, and/or sampling can be focused on special-interest sites
>> (such as within and outside of MPAs).
>>
>> Try to start the surveys before bleaching begins (if possible).
>> Resurvey whenever bleaching occurs, and at intervals during any
>> subsequent period of delayed mortality or recovery until conditions
>> return to “normal.”
>>
>> To assess coral conditions at the population level, with species- and
>> size- specific, information, see the companion BLAGGRA Belt Transects
>> protocol (www.agrra.org/BLAGRRA).
>>
>> Data submitted to the AGRRA project will be processed, summarized,
>> and speedily posted online at the AGRRA website.
>>
>> Please help us create a regionally consistent and comparable
>> database for everyone to use.
>>
>> Judy Lang
>> For the AGRRA Organizing Committee
>> _______________________________________________
>> Coral-List mailing list
>> Coral-List at coral.aoml.noaa.gov
>> http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>
>
More information about the Coral-List
mailing list