courtesy: star.ticketfly
The subject of ocean acidification might be a remote concept to most people. For those who are aware of it, it might be thought of as something that will be a problem only in the future.
But a few oyster and clam lovers might get to experience first hand, and very soon, what ocean acidification really means.
And if you still don't believe in ocean acidification, you might want to travel to a locale where oysters and clams are harvested. The people in those places can tell you firsthand that the problem is real and it is real now.
The problem of oyster scarcity, which hit in the middle of the last century, seemed to have been resolved with the creation of oyster farms. But that now, is under threat too.
And the problem is not just local, it is worldwide. Oceans are turn increasingly acid, and that affects ecosystems everywhere.
It is also happening so quickly, that scientists don't know if they can find a solution fast enough to stop the disappearance of the mollusks altogether.
Ocean acidification is a phenomenon that derives from the escalation of CO2 emissions. Oceans act as a sink for the gas, and that, in turn is pickling the seas. The alkalinity of the ocean is fast changing, and has already changed from a steady 8.2 to 8.1.
That might not seem a lot to many, but it translates to a 30% increase in the acidity level. The projections are even direr: by the end of the century it is projected to be 7.8 or worse.
Although some ocean organisms can actually thrive in this harsher environment, they are not the kind that are very friendly to the ocean and to us. Those include stinging jellyfish, poisonous algae, and some seagrass.
But organisms that rely on the calcification of their shells are in trouble. It's as if an egg were placed in vinegar. Calcium carbonate, the main component of sea shells, cannot be formed if the oceans are acid. The process of calcification is dependent on alkalinity. And without their shell, oyster larvae and clam larvae die, and shellfish and corals fail to grow or thrive.
One large hatchery has already seen a decline of up to 60% of its larval growth due to acidification. One of the things that NOOA observed when it identified the problem, was that the corrosive effect of the increased acidity was worse in those days when winds brought in water from deeper regions, thereby confirming that the ocean's sink effect was indeed collecting more and more CO2 at its bottom. Hatcheries built systems that shut off the surrounding seawater intake on windy days, but this in the long run, might prove insufficient.
Some solutions are being taken into consideration, such as raising the alkalinity of the seabeds near the hatcheries, by placing considerable amounts of carbonate or other alkalinity-raising compounds to balance the waters. Also selective breeding of oysters that can tolerate higher acidity level is being studied.
But in the long run the acidification, unless CO2 production is stopped or diminished, cannot be ignored. Its effects could be catastrophic.
Another startling find on the effects of ocean acidification came last year when NOOA observed a species of sea snails called sea butterflies in the Southern Ocean. Scientists there found that shells were dissolving at much shallower depths than first expected. In fact the observers could just look into the seawall where the pteropods were attached and see their shells flake off like skin off a shedding snake. This might not kill the snails, but it will make them vulnerable to predators and other diseases. And they are an important part of the food chain. For example, a 10% drop in the pteropod population produces a 20% drop in the weight of mature pink salmon.
And that, scientists say, is just the beginning. And even if we diminish or curb our production of CO2, things would not improve for another 30-50 years, because it would take that long for whatever CO2 is already in the air to dissipate.
In effect, scientists say that what we are seeing in the ocean is the output of CO2 that has been dragged into the depths by phytoplankton in the past. What that means is that what is already there is the CO2 product of the years between 1960-1990. The worse of it, i.e., the carbon dioxide produced after 1990 has not even hit us.
source: Slate 2.19.13
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