Coral Reefs dying rapidly

Discussion in 'Diving, Collecting and Environmental Discussions' started by seank, 15 Oct 2008.

  1. seank

    seank

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    Found this interesting read. But I suppose we all knew it was inevitable- well hopefully not:

    Too late to save reefs, says study | Practical Fishkeeping magazine

    Too late to save reefs, says study

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    Picture by John Hanson, Creative Commons.
    It is already too late to save most of the world's coral reefs from ocean acidification, warns a recent study.

    The research by chemical oceanographers Long Cao and Ken Caldeira studied computer simulations of ocean chemistry at different atmospheric levels of carbon dioxide, ranging from 280 parts per million (pre-industrial levels) to 2000 ppm [current levels are at 380 ppm and rapidly increasing].

    The authors found that many of the world's coral reefs would be devastated even if carbon dioxide levels stabilize at 450 ppm, a level well below many climate change forecasts.

    According to Cao, “...even if atmospheric CO2 stabilizes at the current level of 380 ppm, fewer than half of existing coral reef will remain in such an environment. If the levels stabilize at 450 ppm, fewer than 10% of reefs would be in waters with the kind of chemistry that has sustained coral reefs in the past.”

    “If current trends in CO2 emissions continue unabated in the next few decades, we will produce chemical conditions in the oceans that have not been seen for tens of millions of years. We are doing something very profound to our oceans. Ecosystems like coral reefs that have been around for many millions of years just won't be able to cope with the change.” adds Caldeira.

    This study was initiated as a result of Caldeira's testimony before a subcommittee on Fisheries, Wildlife and Oceans of the US Congress in April 2007.

    When asked what stabilization level would be needed to preserve the marine environment, he answered that no such study had yet addressed that question. Cao and Caldeira's study, to be published in the journal Geophysical Research Letters, addresses the gap.
     
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  3. seank

    seank Thread Starter

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    Reef-building corals face extinction

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    Turbinaria mesenterina (Richard Ling, Creative Commons).
    Scientists from 11 countries have conducted the first comprehensive global assessment of reef-building corals and have found that a third of them are threatened with extinction.

    The results of the assessment are published in a recent issue of the journal Science by a team of 39 coral experts led by Kent Carpenter, which applied International Union for Conservation of Nature Red List Criteria and Categories to 845 coral species worldwide.

    The authors found that of the 704 coral species that could be assigned conservation status, 32.8% (231 species) are in categories with elevated risk of extinction (141 species has insufficient data to complete a Red List assessment).

    In the study, the main threats to corals were identified as rising sea temperatures and ocean acidification resulting from climate change and localized anthropogenic stresses resulting from increased coastal development, sedimentation resulting from poor land-use and watershed management, sewage discharges, nutrient loading and eutrophication from agro-chemicals, coral mining, and overfishing.

    The Acroporidae (staghorn coral), Euphylliidae (hammer, torch, frogspawn, bubble, elegance and fox corals) and Dendrophylliidae (sun, cup and pagoda corals) were found to be the most extinction-prone, with about half the species listed in the threatened category; the Meandrinidae (maze corals) and the Oculinidae (galaxy corals) are similarly threatened with about 40% of the species listed as vulnerable.

    The scientists conclude: “[o]ur analysis indicates that the extinction risk for many corals is now much greater than it was before recent massive bleaching events. Whether corals actually go extinct this century will depend on the continued severity of climate change, the extent of other environmental disturbances, and the ability of corals to adapt.

    “If bleaching events become very frequent, many species may be unable to reestablish breeding populations before subsequent bleaching causes potentially irreversible declines, perhaps mimicking conditions that led to previous coral extinctions.

    “If corals cannot adapt, the cascading effects of the functional loss of reef ecosystems will threaten the geologic structure of reefs and their coastal protection function and have huge economic effects on food security for hundreds of millions of people dependent on reef fish.

    “Our consensus view is that the loss of reef ecosystems would lead to large-scale loss of global biodiversity.”
     
  4. ziyaadb

    ziyaadb

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    i think nature will adapt but only time will tell
     
  5. jacquesb

    jacquesb Retired Moderator

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    I agree Ziyaad - BUT - ONLY to a certain degree.... The coral reefs have ALWAYS adapted - IF / WHEN the change was slow....

    BUT - this what is currently happening MIGHT be happening just too quick........
     
  6. Jaak

    Jaak

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    Interesting read Sean, Thanks!
     
  7. Warr7207

    Warr7207

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    Totally horrible :(
     
  8. Andreas

    Andreas

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    Really sad, imagine the damage that will be done in the next 100 years:(Things cant keep on going on like this forever??????
     
  9. seank

    seank Thread Starter

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    Humans have always had a way to overcome, adapt, and eventually fix what they stuffed up. So, hopefully they"ll fix what they did in time
     
  10. seank

    seank Thread Starter

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    Some newish news that is also very interesting:

    ScienceDaily (Apr. 5, 2008) — Coral reefs could be dying out because of changes to the microbes that live in them just as much as from the direct rise in temperature caused by global warming, according to scientists speaking April 2, 2008 at the Society for General Microbiology's 162nd meeting.

    Tropical ecosystems are currently balanced on a climate change knife edge. Corals in coral reefs, which are made up of animals called polyps that secrete hard external skeletons of calcium carbonate, are living perilously close to their upper temperature limits. This makes them very vulnerable to even small temperature rises of 1-2 degree Celsius above the normal summer maximum.

    "Many of the deaths we see in the coral reefs, which occur following coral bleaching events, when huge areas of reef die off like in 1998 when 17% of the world's reefs were killed, can be put down to changes in the microbes which live in and around the reefs," says Dr John Bythell, a biologist from Newcastle University. "These microbes can be thought of as being similar to the bacteria that normally live in our guts and help us digest our food."

    Changes in sea temperature caused by climate change and global warming affect corals, but they also affect the types of bacteria and other microflora that live with them. When the water warms up, some disease-causing bacteria are more successful and can attack the corals. The corals themselves suffer from heat, which reduces their defences. Also, some of the friendly bacteria that normally live in the corals' guts become weakened, allowing other harmful bacteria to multiply and cause diseases or other problems.

    For many communities in developing countries, which rely on coral reefs for their fisheries and tourism income, the loss of coral reefs has major impacts on their economies. They also lose valuable coastal defences and land to coastal erosion, affecting human welfare in the communities.

    "We need a better understanding of the processes and mechanisms that impact on corals and the reefs when sea temperatures rise to confirm the ultimate causes of their decline," says Dr Bythell. "Although local actions to reverse the overall decline in reef health are probably not feasible, we need this better understanding to try to reduce or eliminate contributing causes. Some of the changes in the microbes' environment could be locally managed, for example by reducing general pollution, cutting soil erosion into the sea which chokes the reefs, and avoiding harmful run-off from farming practices."

    A key factor newly identified by the Newcastle team is the role of surface mucus secreted by corals. This seems to act as a shield, preventing disease-causing pathogens such as bacteria and some viruses from penetrating their tissues.

    "The reefs' defensive mucus or slime is also at risk from stresses brought on by climate change. This seems to happen just at a time when some of the key functional microbe groups are changing, reducing the corals' other defences and boosting some disease-causing bacteria, making them more virulent," says Dr Bythell.
    "If we want to protect and conserve these reefs for the future, we need to start acting now. And before we can do that we need a better understanding of the processes," says Dr John Bythell. "The mass mortality of two of the dominant coral species in the Caribbean due to disease has been unprecedented in the last 3,000 years, which suggests a strong link to man-made activities."

    The Newcastle scientists are concerned that despite the clear relationship to underlying factors affecting the reefs which cause the diseases and bleaching, and the important role played by the microbes, microbiology and coral cellular biology are investigated largely independently by different groups of researchers using different approaches. According to Dr Bythell, scientists' attempts to identify the underlying problems would be improved by combining molecular microbial techniques with coral cell and molecular approaches.
     
  11. seank

    seank Thread Starter

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    Bio-Rock: Shock Treatment for Coral Reefs

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    Given the level of systematic abuse coral reefs have sustained over the last few decades, helping to rehabilitate them by administering - in essence - a form of shock treatment hardly seems like a good idea. Yet that is the technique Thomas Goreau, a scientist and one of the originators of the "Bio-Rock" project, has been using to help restore the once lush coral reefs off Bali in Indonesia.
    The brainchild of Goreau and Wolf Hilbertz, the late architect, the "Bio-Rock" project consists of setting up dozens of metal structures fed by cables bringing low-voltage electricity around coral reefs. Zapping the reefs has helped restore and, in some cases, spur their growth, Goreau claims. Before Hilbertz passed away, the duo had managed to set up similar projects in close to 20 countries around the world.
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    The electricity helps jump-start the corals' healing process by facilitating the aggregation of limestone - a key building component of reefs - on the metal structures. Once enough limestone gathers in one area, divers can affix fragments of live coral from damaged reefs to the structures. The reefs in Bali have responded very well to the shock therapy - with their renewed growth once again attracting a variety of fish and other organisms.
    The main challenge Goreau has encountered so far is a severe lack of funding. Many have criticized the efforts as being too limited in scope, a problem Goreau readily acknowledges - though he is quick to point out that additional funding could give him the seed money to replicate the project on other threatened reefs. He is hoping to gain some financial backing at the UN Conference this week after he presents the results of his work.
    "Under these conditions, traditional (revival) methods fail. Our method is the only one that speeds coral growth," Goreau said.
     
  12. seank

    seank Thread Starter

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  13. sunburst

    sunburst

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    Will never adapt. The drop in sea pH will slow growth rates combined with mass bleaching events will cripple the ability for rejuvenation.

    There are no climate models that can predict what will happen in even 5 years. For instance the polar ice thaw witnessed last year were 50 years ahead of even the most pessimistic models.

    The only way is Govt. This will not happen as govt needs taxes and taxes come from industry. Industry/business needs energy.
    Great read thanks. Took this exert which mentions what we already know but important why the current trend is not ethical....

    The global sea level rise caused by climate change, severely threatening many of the world's coastal and low-lying areas from Bangladesh to East Anglia, is proceeding faster than UN scientists predicted only five years ago, Professor Chris Rapley, director of the British Antarctic Survey, said yesterday.


    Climate change is causing sea levels to rise around the world because water expands in volume as it warms, and because land-based ice, such as that contained in the Greenland and Antarctic ice sheets, adds to the volume when it melts and slips into the sea.

    Rises of this order will present a substantial threat of flooding, storm surge and even complete submersion of many of the world's populous low-lying areas,such as Bangladesh, the Nile Delta and even London.
     
  14. Nosaj

    Nosaj

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    Ya and what is worse, every single one of us on this site who has bought a coral and/or any reef organism is seriously adding to the problem...
     
  15. Warr7207

    Warr7207

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    I wouldn't worry the Earth Gaia, will correct the imbalance in her own time.
     
  16. sunburst

    sunburst

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    Inevitable. But the poor must pay
     
  17. jacquesb

    jacquesb Retired Moderator

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    I agree - mother earth with fix itself - over time.
    We might just not be around when this happens.... :(
     
  18. Falcon

    Falcon

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    theres something thats bugging me....why are the reefs all looking so brownish and not as bright as some peoples tanks?i'm sure it's not just lighting....is this because of the polution in the ocean or is not yet such a big factor with CORAL COLOUR?

    i'm not talking bout growth only talking colour here as most reef pics i seen lately only the fish seem very colourfull so surely its not lighting...
     
  19. Warr7207

    Warr7207

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    Because a "brown" is a healthier coral than an insanely coloured tank coral.

    The colour is how the coral protects it's symbiotic algae from the huge amounts of UV we pump into them.

    Also these colours come about because of the higher kelvin lights we use, compared to the sun's lower rating.
     
  20. jacquesb

    jacquesb Retired Moderator

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    Warr has it SPOT ON! You 100% correct Falcon. I SCUBA dive, and neither have I seen any corals (SPS) so colorful.....
     
  21. Alan

    Alan Admin MASA Contributor

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    IMO, i dont think its all doom and gloom for the reefs, they were here long before us and have survived catastrophic changes so i would like to think they will be around long after us.
     
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