After record, mind-numbing coral bleaching, what would it take to “Save the Reef”? #Auspol

Global warming impacts right now are beyond some of the worst scientific predictions, so what does that mean for aspirations to save the Great Barrier Reef?
On 6 July 2009, Australian Dr Charlie Veron — who has discovered, described and identified about a third of all known coral species — addressed the Royal Society in London and asked: “Is the Great Barrier Reef on death row?” His response: “The answer must be yes… a close look at this question from any rational perspective arrives at the same bottom line: the Great Barrier Reef can indeed be utterly destroyed, and this could easily happen in the lifetime of my children.”
It is a devastating answer because corals have been around for almost 500 million years and have formed more fossils than any other species, they are home to one-quarter of marine fish species, and tens of millions of people depend on reef ecosystems for protein and other services. The Great Barrier Reef (GBR) is home to 600 different types of corals, and is more biodiverse that any other UNESCO World Heritage site.
Now, in 2016, we have seen why Charlie Veron was so worried, with mass coral bleaching unprecedented in scale and severity occurring across the Reef in March. It was driven by a 1°C rise in sea temperatures compared to the recent average (2002-2011). Worryingly, there’s little sign that those sea temperatures are returning to normal in the short run, so more damage may still be occurring.
Of 911 reefs surveyed by scientists since the bleaching, 500 were severely bleached. Of the 522 reefs surveyed in the more pristine and isolated northern sector (stretching 1000 kms from Port Douglas north to Torres Strait), 81% were severely bleached. Scientists report that: “North of Port Douglas, we’re already measuring an average of close to 50% mortality of bleached corals. At some reefs, the final death toll is likely to exceed 90%. When bleaching is this severe it affects almost all coral species, including old, slow-growing corals that once lost will take decades or longer to return.”


 The bleaching exhibits a gradient of decreasing severity from north to south along the Reef.

Coral bleaching
Coral polyps are invertebrates similar to minute jelly fish, which build limestone (calcium carbonate) structures, and live in a symbiotic relationship with algae-like unicellular zooxanthellae that reside within the coral structure, and give it colour.
The coral provides the algae with a protected environment and compounds they need for photosynthesis. In return, the algae produce oxygen and help the coral to remove wastes. Most importantly, zooxanthellae supply the coral with glucose, glycerol, and amino acids, which are the products of photosynthesis.

Corals survive within a narrow water temperature band, and suffer heat stress and expel zooxanthellae if the ocean temperature get too high. Bleaching events vary intensity. In the extreme case, all zooxanthellae are expelled and the living colony will appear totally white (hence “bleaching”). As elevated sea temperatures persist, coral mortality rates increase. 
Charlie Veron explains:

Coral mortality means the corals have expelled all zooxanthellae, and starve to death, which may take months. Corals may recover, if there are any zooxanthellae left in their tissues, but if not death appears to be inevitable.

Put bluntly, more than half the corals north from Port Douglas have already been identified as dead, and as observations continue over the next few months that figure is likely to rise sharply. Climate change has just killed most corals in the Great Barrier Reef’s highest-value section. 
Coral expert Prof. Ove Hoegh-Guldberg says that “An increase of as little as 1-2°C on top of regular summer temperatures can mean the difference between life and death for coral reefs.”
Previously, the most widespread bleaching events on the GBR occurred in the summers of 1998 and 2002, with 42% and 54% respectively of reefs bleached to some extent, and 18% strongly bleached. However coral losses on the Reef between 1995 and 2009 were largely offset by growth of new corals.

Press link for more: Climate Code Red

Advertisements

4 comments

  1. The effects of climate disruption are an on-going tragedy brought on by human hubris, greed, and stupidity. Mom, as I call Mother Nature, is angry, and she has already begun extracting her revenge upon us. WHEN will humanity rise up and say “NO MORE!” to the destroyers of life on Earth as we know it? Will it happen in time? And do humans even deserve a second chance? We have, for the most part, been terrible stewards of our planet and of each other. We seem to be a promising experiment gone terribly bad. Maybe it’s a chance for a wiser life form to take hold and succeed where we have so miserably failed. Just so you know, should there form a global movement of ALL peoples demanding an end to the burning of carbon-based fuel, my pitchfork and torch are at the ready to storm “the Bastille.”

  2. Saludos. Me ha agradado leer su reseña. Me ha semejado una enseñanza muy cautivadora, aún, en determinados puntos difiero un poco de tu parecer.
    He advertido que tiene más manifestaciones, propongo atrapar un lapso para adivinarlas.
    Ten por fiable que seguiré todas tus informaciones.
    Te congratulo por tu portal web. Un devoto saludo.

Appreciate your comments John

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s