| July 6, 2010 – Coral Bleaching Update, Koh Tao |
Over the last few months increasing sea temperatures and intense sunlight coupled with flat calm seas and low tides have lead to the most stark and vivid changes to our reefs on Koh Tao that any of us have ever seen.
Coral Bleaching has turned many of our corals a stark white colour with the threat lasting throughout a good part of April and May. (See our Bleaching Report in May for Full details)
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Mushroom coral showing signs of recovery |
June (especially late June) saw a huge reduction in the stress on the local reef. See temperatures dropped back to 30 degrees Celsius (from highs of 32 underwater and up to 34 on the surface, wind and cloud cover increased, visibility dropped all aiding the recovery of the coral.
What we are starting to see now is an increase in the abundance of symbiotic algae in the corals that have survived. Some corals have suffered mortality, but these thankfully seem limited to a few less robust species mostly of the family acropora. This recovery is evident in the increase in colour (from a stark white to a light brown or green and finally to a darker brown) with the hope that favourable conditions will continue, water temperatures will remain stable (or decrease) and the corals will continue to return to health. |
This branching coral is coming back to life.
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We have continued our monitoring efforts using a number of methodologies at our disposal – Reef Check’s Eco Monitoring (www.reefcheck.org), Project Aware’s Coralwatch (www.coralwatch.org) and our own tagged, numbered corals have been monitored using and photographic surveys. It is important to collect as much data as we can during this unusual phenomenon to establish the resilience of our local ecosystem.
Assuming recovery continues what we hope to determine is which corals are more robust and resilient to such events so that for future reef restoration projects we can look at protecting and preserving those species that are likely to survive. |
This branching coral has died due to the stress. |
This porites coral is starting to show signs of its broan, healthy colour. |
We still have a long way to go but the signs are encouraging. If you would like to join us for any monitoring or restorative activities email nath@ecokohtao.com or logon to www.facebook.com/ecokohtao for upcoming events.
Nathan Cook
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PADI IDC Staff Instructor #479720
Reef Check Trainer
Manager Environmental Awareness and Action
Eco Koh Tao
E: nath@ecokohtao.com, www.ecokohtao.com |
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