Thursday, August 03, 2006

Altered Oceans

A chemical imbalance, creating higher levels of acidity in our oceans, threatens to wipe out coral, fish and other crucial species worldwide.

Marine biologist Victoria Fabray has been conducting an experiment with cold-water snails called pteropods. She had them in plastic jars filled with seawater, little microcosms of the world's oceans. These snails are found in the coldest waters; in her experiment, she put them into sealed jars. The snails expend carbon dioxide, which in turn makes the water more acidic. Within 36 hours, their shells were disolving from the acidity.

As industrial activity pumps massive amounts of carbon dioxide into the environment, more of the gas is being absorbed by the oceans. As a result, seawater is becoming more acidic, and a variety of sea creatures await the same dismal fate as Fabry's pteropods.

The greenhouse gas, best known for accumulating in the atmosphere and heating the planet, is entering the ocean at a rate of nearly 1 million tons per hour — 10 times the natural rate.

I'm a scuba diver - not a great one, but I love to dive. I've seen evidence of coral bleaching, another result of chemical imbalance and greater than normal ocean temperatures. Coral bleaching has many potential harmful impacts. Corals die faster after bleaching starts. Coral death is proportional to how long water temperature has been higher than normal. The greater the amount of bleaching, the more likely the coral will die. However, if corals survive bleaching, their reproductive capacity is greatly reduced and reef productivity and growth is diminished. Without the nutrients produced by coral, fish die. It goes on, and on.

Scientists report that the seas are more acidic today than they have been in at least 650,000 years. At the current rate of increase, ocean acidity is expected, by the end of this century, to be 2 1/2 times what it was before the Industrial Revolution began 200 years ago. Such a change would devastate many species of fish and other animals that have thrived in chemically stable seawater for millions of years.

Primitive life forms will likely survive, to the detriment of higher forms of sea life. Corals and shells will be come too fragile to withstand the pounding of waves.

Oceans have been a protective barrier against carbon dioxide when increases are gradual. Were it not for our oceans, the average temperature increase over the last several years would be higher; glaciers would be gone by now. When carbon dioxide is added to the ocean gradually, it does little harm.

Today, however, the addition of carbon dioxide to the seas is anything but gradual.

Scientists estimate that nearly 500 billion tons of the gas have been absorbed by the oceans since the start of the Industrial Revolution. That is more than a fourth of all the CO2 that humanity has emitted into the atmosphere. Eventually, 80% of all human-generated carbon dioxide is expected to find its way into the sea.

The increase of CO2 in the oceans creates carbonic acid, which can cause heart attacks in some fish. Geological records show that there has not been a change in the oceans PH levels in 650,000 years, til recently. The current changes, if they continue at their current pace, will change by 150% by the end of the century.

The last time ocean chemistry underwent such a radical transformation, Ken Caldeira, an expert on ocean chemistry and carbon dioxide at the Carnegie Institution's department of global ecology, said, "was when the dinosaurs went extinct."

Scientists say the acidification of the oceans won't be arrested unless the output of CO2 from factories, power plants and automobiles is substantially reduced. Even now, the problem may be irreversible.


robin andrea said...

It amazes me that people will kill and die to defend a little piece of land, a made-up boundary, but not lose any sleep over the suffering planet. What we do to the seas is truly horrible, and we will be repaid in kind, of that I am certain.

DivaJood said...

Robin, if we don't reverse global warming, we won't have a planet at all. But, that's a minor technicality to Bushco.

Helen Wheels said...

It's so galling I can't get my mind around it. At least SOME folks are trying to do something. This country is mainly responsible, as well, being by far the biggest polluter. Sigh. If Iceland can go fossil-fuel-free by 2050, why can't everyone???

DivaJood said...

Helen, everyone can. But when a country's administration is all about big oil, it's going to be tough. Can't wait to see "Who killed the electric car."