Coral Bleaching Revisited

Discussion in 'Environment' started by westwall, Apr 12, 2011.

  1. westwall
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    westwall USMB Mod Staff Member Gold Supporting Member Supporting Member

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    Just wanted to get your attention. Florida just had the first coral bleaching event in 30 years...due to cold! Bet you never knew corals could die from the cold did you?

    NOAA and partners from 12 organizations surveyed sites in the Florida Keys to determine the extent of coral bleaching, and death, in the wake of record low-water temperatures. Scientists assessed coral health at more than 78 sites from January 25 to February 12 to determine the severity of coral bleaching and reefs most affected.

    During the first two weeks of January 2010, water temperatures in some parts of the Keys dropped into the upper 40s and lower 50s, which is about
    20 degrees Fahrenheit lower than the typical temperatures of the upper 60s and lower 70s. The lethal lower limit for corals is 60 degrees Fahrenheit.


    First Florida Cold-water Bleaching Event in 30 Years
     
  2. Old Rocks
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    Old Rocks Diamond Member

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    I think a comparison of the scope of warm water induced bleaching, and that created by the influx of cold water experiance by some corals this winter. According to your article, most corals were not affected.

    » 80 Percent of Caribbean Corals Suffer Bleaching Due to Heat Stress Ecology Today: Ecology News, Information & Commentary Blog

    Coral reefs suffered record losses as a consequence of high ocean temperatures in the tropical Atlantic and Caribbean in 2005 according to the most comprehensive documentation of basin-scale bleaching to date. Collaborators from 22 countries report that more than 80 percent of surveyed corals bleached and over 40 percent of the total surveyed died, making this the most severe bleaching event ever recorded in the basin. The study appears in PLoS ONE, an international, peer-reviewed, open-access, online publication.

    “Heat stress during the 2005 event exceeded any observed in the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in at least 150 years,” said C. Mark Eakin, Ph.D., coordinator of NOAA’s Coral Reef Watch Program. “This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems, and events like this are likely to become more common as the climate warms.”

    First Florida Cold-water Bleaching Event in 30 Years

    This survey data will support greater understanding about coral reefs and guide efforts to protect these critical habitats. Researchers are still exploring whether this cold-stress event will make corals more susceptible to disease. Following warm-water stress events, the bacterial makeup of corals changes, increasing the prevalence of coral disease. This winter’s event allows scientists to collect data to compare and contrast coral health following both cold- and warm-water events.
    Florida Keys National Marine Sanctuary, the manager of most Florida Keys coral reef resources, is working with the science community and limiting certain consumptive activities in the hardest hit areas until stressful conditions subside. The Sanctuary is also asking SCUBA divers to enjoy the many reefs not affected by January’s cold weather
     
  3. wirebender
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    wirebender Senior Member

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    Back in 1997, alarmists told us that by 2010 40% of the worlds coral would be gone.

    ABC News Watch: Past Alarm. World's Coral: 40% gone by 2010

    Back then, the world's coral was estimated to be something like two hundred and fifty five thousand square kilometers.

    SpringerLink - Coral Reefs, Volume 16, Number 4

    Today, the world's coral is estimated to be over 249,700 square kilometers.

    http://pdf.wri.org/factsheets/factsheet_reefs_main.pdf

    How long do you think it will be before alarmists try to flush that failed prediction down the same hole they tried to flush the 50 million climate refugees?

    It simply amazes me that anyone still places creedence in the alarmist side of the argument considering that nothing they predict ever seems to materialize.
     
  4. Old Rocks
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    Old Rocks Diamond Member

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    http://www.princeton.edu/step/people/faculty/michael-oppenheimer/research/Donner2.pdf

    Abstract
    Elevated ocean temperatures can cause coral bleaching, the loss of colour from reefbuilding
    corals because of a breakdown of the symbiosis with the dinoflagellate
    Symbiodinium. Recent studies have warned that global climate change could increase
    the frequency of coral bleaching and threaten the long-term viability of coral reefs. These
    assertions are based on projecting the coarse output from atmosphere–ocean general
    circulation models (GCMs) to the local conditions around representative coral reefs.
    Here, we conduct the first comprehensive global assessment of coral bleaching under
    climate change by adapting the NOAA Coral ReefWatch bleaching prediction method to
    the output of a low- and high-climate sensitivity GCM. First, we develop and test
    algorithms for predicting mass coral bleaching with GCM-resolution sea surface temperatures
    for thousands of coral reefs, using a global coral reef map and 1985–2002
    bleaching prediction data. We then use the algorithms to determine the frequency of
    coral bleaching and required thermal adaptation by corals and their endosymbionts
    under two different emissions scenarios.
    The results indicate that bleaching could become an annual or biannual event for the
    vast majority of the world’s coral reefs in the next 30–50 years without an increase in
    thermal tolerance of 0.2–1.0 1C per decade. The geographic variability in required thermal
    adaptation found in each model and emissions scenario suggests that coral reefs in some
    regions, like Micronesia and western Polynesia, may be particularly vulnerable to
    climate change. Advances in modelling and monitoring will refine the forecast for
    individual reefs, but this assessment concludes that the global prognosis is unlikely to
    change without an accelerated effort to stabilize atmospheric greenhouse gas concentrations.
     
  5. Old Rocks
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    Old Rocks Diamond Member

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    Two good studies with somewhat differant approaches and conclusions.

    Disturbance and the Dynamics of Coral Cover on the Great Barrier Reef (1995

    Coral reef ecosystems worldwide are under pressure from chronic and acute stressors that threaten their continued existence. Most obvious among changes to reefs is loss of hard coral cover, but a precise multi-scale estimate of coral cover dynamics for the Great Barrier Reef (GBR) is currently lacking. Monitoring data collected annually from fixed sites at 47 reefs across 1300 km of the GBR indicate that overall regional coral cover was stable (averaging 29% and ranging from 23% to 33% cover across years) with no net decline between 1995 and 2009. Subregional trends (10–100 km) in hard coral were diverse with some being very dynamic and others changing little. Coral cover increased in six subregions and decreased in seven subregions. Persistent decline of corals occurred in one subregion for hard coral and Acroporidae and in four subregions in non-Acroporidae families. Change in Acroporidae accounted for 68% of change in hard coral. Crown-of-thorns starfish (Acanthaster planci) outbreaks and storm damage were responsible for more coral loss during this period than either bleaching or disease despite two mass bleaching events and an increase in the incidence of coral disease. While the limited data for the GBR prior to the 1980's suggests that coral cover was higher than in our survey, we found no evidence of consistent, system-wide decline in coral cover since 1995. Instead, fluctuations in coral cover at subregional scales (10–100 km), driven mostly by changes in fast-growing Acroporidae, occurred as a result of localized disturbance events and subsequent recovery.
     
  6. waltky
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    waltky Wise ol' monkey Supporting Member

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    Sunscreen ingredient linked to coral damage...

    Study: Oxybenzone in Sunscreen Linked to Coral Damage
    October 20, 2015 - Using sunscreen can cut your risk of developing some of the most dangerous forms of skin cancer by 50 percent. Unfortunately, a new study suggests it also may be doing severe damage to already threatened coral reefs around the world.
     
  7. Billy_Bob
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    Billy_Bob Platinum Member

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    So which is the greater danger there old fraud? The heat that doesn't exist or the cold that does?
     
  8. waltky
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    waltky Wise ol' monkey Supporting Member

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    Great Barrier Reef suffered worst bleaching on record in 2016...

    Great Barrier Reef suffered worst bleaching on record in 2016, report finds
    Mon, 28 Nov 2016 - This year saw the worst-ever destruction of coral on the Great Barrier Reef, a new study finds.
     
  9. Old Rocks
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    Old Rocks Diamond Member

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    And once again, we see what an idiot that Mr. Westwall is.

    Bleaching Hits 93 Percent of the Great Barrier Reef
    Aerial surveys reveal that the giant coral reef is suffering under global warming

    We knew coral bleaching was a serious issue in the Great Barrier Reef, but the scope of just how widespread it was has been unclear—until now.

    Extensive aerial surveys and dives have revealed that 93 percent of the world’s largest reef has been devastated by coral bleaching. The culprit has been record-warm water driven by El Niño and climate change that has cooked the life out of corals.

    The unprecedented destruction brought leading reef scientist Terry Hughes, who runs the ARC Center of Excellence for Coral Reef Studies, to tears.

    We’ve never seen anything like this scale of bleaching before. In the northern Great Barrier Reef, it’s like 10 cyclones have come ashore all at once,” Hughes said in a press release.

    The Center conducted aerial surveys and dives at 911 sites spanning the full 1,430-mile length of the reef. They show the hardest hit areas are in the northern part of the reefs, which have also endured some of the hottest water temperatures for prolonged periods.

    More than 80 percent of reefs surveyed there showed signs of severe bleaching. The southern end of the reef fared better, but overall the bleaching represents a massive blow to biodiversity at the UNESCO World Heritage Site.

    Bleaching Hits 93 Percent of the Great Barrier Reef
     

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