PDA

View Full Version : Caribbean coral bleaching threat



wgt
07-27-2009, 12:24
2005 revisited?

NOAA - NOAA: Coral Bleaching Likely in Caribbean (http://www.noaanews.noaa.gov/stories2009/20090722_coralbleaching.html)

wwdiver
07-27-2009, 14:28
Well, that sucks. I often wonder how much longer the reefs will be around, or maybe I'm just being cynical?

wgt
07-27-2009, 14:59
I think that you have asked a fair question and do not believe that you are being cynical.

Should climatic trends (of whatever source) continue, then we should perhaps expect to see a global redistribution of species, with traditionally more temperate waters beginning to express corals, at least in shallows penetrable by sufficient sunlight year-round (remember that the algae that partner with corals contribute photsynthesized sugar). If frank regional decimation of coral indeed occurs consequent to the interaction of increased global temperatures and other stressors, then I would expect increased expression of sponges in these decimated zones. This is a sad substitute, however, as we would also see the loss of species that depend on hard corals (e.g., butterfly fish).

Certainly, corals have regionally come and gone throughout geological history as environmental conditions changed. If this predicted bout of bleaching (2009) and perhaps the devastating Caribbean bleaching of 2005 simply reflect the historically precedented course of climatic change on earth, then a sad "oh well" is warranted, I guess. On the other hand, if such devastation is anthropogenic (i.e., caused by humans) and hence avoidable through some responsible economic and social remodeling, then this regional tragedy may be a warning sign of an lamentable global disaster.

I wish I knew the answers. Not knowing all the facts, however, ought not to excuse environmental irresponsibility.


Well, that sucks. I often wonder how much longer the reefs will be around, or maybe I'm just being cynical?

fire diver
07-27-2009, 16:13
I also think we should keep in mind that millions of years ago the earth was much hotter than it is today. The coral's seemed to do just fine then, as evidenced by the billions of cubic yards of limestone throughout the world that was laid down by ancient corral reefs.

I agree that "losing" the reefs we have right now will really suck, but they won't disappear all together.

wwdiver
07-27-2009, 17:58
I appreciate both of your replies. WGT, I think you stated your position both factually and tactfully. Fire Diver, I think there is probably truth to your statement but I am rather selfish: I think we, at this time in history, have been given a gift of nature that has indeed taken millions of years to come to fruition and it pains me that we are $%##!&! it up. I remember 20 years ago trying to explain to people that human behavior and population growth would almost certainly have a detrimental impact upon our environment and that it could be almost exponential as other countries around the world began building their own economies if they based that growth upon the model of our own industrial revolution. I know most people thought I was nuts to think that man could have a measurable impact upon something as big as the planet. I think the scientific community has fully substantiated my beliefs. When I talk to my non diving friends and family, I tell them to go see the reefs NOW 'cause who knows what we'll all be left with in 100 years.

wgt
07-28-2009, 07:14
During the last half-billion years, global temperatures have peaked roughly each hundred thousand years. We are about right on schedule for one of these peaks, and current mean global temperature is within about 3 degrees of its highest points during that 500,000-yr period.

Where we are now truly deviant relates to atmospheric CO2 accumulation. During that same 500,000-yr period, global changes in temperature and concentrations of atmospheric CO2 closely followed each other. During the last century (plus a few years), we have sculpted global culture based on the rapid incineration of energy stores that required millions of years to accumulate. To put this rate of incineration into perspective, a single liter of gasoline is the product of almost almost 25 tonnes of aquatic organic material. The annual global consumption of fossil fuels is therefore equal to the burning of all of the plant matter grown on land and on the surfaces of the ancient oceans over 400 - 500 years. Now that is a forest fire!!!!

The apparent consequence is that CO2 levels and global temperature have become uncoupled since the advent of the industrial revolution. Atmospheric CO2 concentrations are now about 25% higher than at any other point during the above-noted 500,000-yr period. We are clearly entering period of uncertain energy dynamics. Since we do not seem to be curbing the accumulation of CO2, a reasonable (but unconfirmed) prediction is that global temperatures will escalate to unprecedented levels with potentially catastrophic consequences.

In the immediate term, I would simply be saddened to see a repeat of 2005, when vast stretches of Caribbean sea floor looked like the remains of a giant snowball fight that heralded the mass death of the colonies, irrespective of whether industrial practices are to blame.

Thanks for chiming in, wwdiver and fire diver.


I also think we should keep in mind that millions of years ago the earth was much hotter than it is today. The coral's seemed to do just fine then, as evidenced by the billions of cubic yards of limestone throughout the world that was laid down by ancient corral reefs.

I agree that "losing" the reefs we have right now will really suck, but they won't disappear all together.