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Title: Acidic Oceans Ahead. Plan Wisely.
Source:
ONEarth.org
URL Source: http://www.onearth.org/node/1823
Published: Jan 19, 2010
Author: Emily Gertz
Post Date: 2010-01-23 16:58:58 by buckeroo
Keywords: None
Views: 156
Comments: 5
The sharp increase in atmospheric carbon dioxide over the past two centuries years is transforming the chemistry of the world's oceans: As they have soaked up excess CO2, the pH balance of seawater -- the extent to which it is "acid" versus "basic" -- has shifted toward the more acidic. "Climate change and ocean acidification are two sides of the same coin," says Sarah Cooley, a postdoc in marine chemistry and geochemistry at the Woods Hole Oceanographic Institution. "Ocean acidification comes from the rising carbon dioxide levels in the atmosphere, and so does climate change, but at that point they diverge" into very different patterns of cause-and-effect. As the ocean's carbon dioxide load is increasing, the amount of carbonate minerals in the water is decreasing, with the potential to render the marine environment a lot less hospitable to many animals. Over the next 90 years, this may well cause enormous economic losses worldwide, with the impacts reverberating very strongly through coastal communities. Community leaders have tended not recognize the potential for ocean acidification to disrupt both economies and quality of life. In the December 2009 issue of the journal Oceanography, Cooley and colleagues offer the beginnings of a framework for thinking through such challenges. "One thing that we hope that we're contributing is a look at what ocean acidification could do from a communities perspective," she says, to help planners and policymakers think about a complex scientific issue in terms they're most familiar with: dollars and cents. "Assuming you could track a dollar through the economy, it could go all these different routes," says Cooley. "It might pay for a shellfish ornament" at a tourist gift shop, "but it might also pay for a dentist or a lawyer or a teacher." A failing shellfish fishery doesn't just mean fewer scallops for dinner at a fine restaurant. It may lead to closing schools, reducing public services, and an exodus of population to find work. "When you pose things in these terms, people stop and think, 'I didn't think about the possible effects on schools. I didn't consider that not just tourists, but also the service industries might be influenced...that could be me, that could be my neighbor.' Cooley says her work borrows a great deal from the work ecological economists are doing in anticipating the economic and social costs of global warming. "We're borrowing a page from their playbook and doing the same in terms of ocean acidification." The economic impacts of ocean acidification may well be in the billions and trillions of dollars. Corals need carbonate minerals to build their hard branching shells. If changing marine pH levels affect coral reefs, they will be less able to protect shorelines from tides and storms, or provide fish habitat. These ecosystem services add up to an estimated $30 billion annually. Vanishing corals would also weaken the tourist economies of many nations. Cooley profiles the potential costs to Tobago, where coral reef tourism directly and indirectly generates about 30 percent of the island's gross domestic product. Fisheries, the main source of protein for around one billion people worldwide, will also be harmed by a more acidic ocean. Since myriad organisms up and down the food chain depend upon carbonate minerals to build their protective shells -- ranging from tiny foraminifera, which are at the base of the marine food chain, to species like scallops, oysters, clams, and mussels -- both shellfish and finfish species will both be at risk. The UN Food and Agriculture Organization estimates that the combined value of wild and farmed fisheries worldwide is around $170 billion a year. Despite the bleak scenarios intrinsic in her study -- disappearing fish, fewer jobs, and unraveling communities (not to mention a shortage of seashell-covered ashtrays) -- Cooley emphasizes that her work is meant to inspire pragmatism, not despair. "We need to be thinking ahead toward changes, not necessarily extinctions or catastrophic events," she says. "The point is not that 'All ocean life isn't gong to disappear.' It's like defensive driving-- you take precautions now so you won't have an accident later." Image: "Calculated saturation states of aragonite, a form of calcium carbonate often used by calcifying organisms. Shades of red indicate areas where levels are so low that organisms may be unable to make new shells or skeletons, and where most unprotected aragonite structures will dissolve. By the end of this century, polar and temperate oceans may no longer contain enough aragonite to support the growth of calcifying organisms such as some mollusks, crustaceans, and corals.
Poster Comment:
Expect the price of a nice fish dinner to go up NOT by the huge population demands BUT also the diminushing capabilities of the fisheries, themselves.
(1 image)
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#1. To: All (#0)
One of the most common negative responses Sarah Cooley gets when she speaks to community groups about ocean acidification is, “What do you mean, ocean acidification? The ocean is not acidic! Seawater is never going to get below pH 7—so you must not know what you’re talking about.” That’s partly true, said Cooley, a postdoctoral researcher at Woods Hole Oceanographic Institution. The pH of seawater is near 8, which makes it mildly alkaline, or basic; but any decrease in the pH of a liquid is considered “acidification.” “It’s a lot easier to say ‘ocean acidification’ than ‘ocean de-alkalinization,” said Cooley. pH is an index of how many protons, or hydrogen ions (H+) are dissolved and free in a solution. The pH scale goes from 0 to 14. A fluid with a pH of 7 is neutral. Below 7, it is acidic; above 7, it is alkaline. The more below or above 7 a solution is, the more acidic or alkaline it is. The scale is not linear—a drop from pH 8.2 to 8.1 indicates a 30 percent increase in acidity, or concentration of hydrogen ions; a drop from 8.1 to 7.9 indicates a 150 percent increase in acidity. Bottom line: Small-sounding changes in ocean pH are actually quite large and definitely in the direction of becoming less alkaline, which is the same as becoming more acidic. If you think about it, we use descriptive words like this all the time. A person who stands 5’5” tall and weighs 300 pounds isn’t thin. If he loses 100 pounds, he still won’t be thin, but he will be thinner than he was before he went on the diet. (And we are more likely to comment that he’s looking trimmer than to say he’s not as fat as he used to be.) It’s the same with ocean acidification. Seawater is not acidic, nor is it ever likely to be; but because of the buildup of CO2 in our atmosphere, more CO2 is absorbed by the oceans. That makes them more acidic than they used to be—and a lot more acidic than is healthy for corals, clams, oysters, and many other organisms that make their shells or skeletons out of calcium carbonate. The increased acidity doesn’t corrode the shells and skeleton, per se; rather the excess H+ ions bond with carbonate ions to make bicarbonate, leaving fewer carbonate ions available for organisms to use in shell-building and requiring a greater outlay of energy by the calcifying organisms. The origin of the term “pH” is unclear. The “H” stands for hydrogen ions; the “p” has been suggested to mean either “power” (so pH would mean “the power of hydrogen ions”) or “negative logarithm” (referring to the mathematical description of hydrogen ion concentration). “I used to think, when I was younger and didn't know any better, that surely whoever was elected the next time would be better than the current president. But I learned a long time ago that it gets worse every (s)election, not better.” -- James Deffenbach, circa Jan. 2010
I read the "p" stands for potential. High pH means it has high potential to absorb hydrogen. But... who knows??
This is significant. The acidic rise in some bodies of water has already caused coral rock to erode and some forms of sea life to leave (or vanish), while - sometimes - other forms of sea life move in. Ultimately this may make some edible fish unavailable, as least at affordable prices. And there will be a disruption of the usual food chain which could have serious long-range effects.
But... who knows?? Back in college chemistry, that is the way I understood the jargon, too; that is to say, acids are formed.
“I used to think, when I was younger and didn't know any better, that surely whoever was elected the next time would be better than the current president. But I learned a long time ago that it gets worse every (s)election, not better.” -- James Deffenbach, circa Jan. 2010
My wife and I enjoy having a plate of oysters on occasion. Those days are going away and only the super-rich are going to have the delicacy because the harvest yields shall become so small in the not too distant future.
“I used to think, when I was younger and didn't know any better, that surely whoever was elected the next time would be better than the current president. But I learned a long time ago that it gets worse every (s)election, not better.” -- James Deffenbach, circa Jan. 2010
#2. To: buckeroo (#1)
The “H” stands for hydrogen ions; the “p” has been suggested to mean either “power” (so pH would mean “the power of hydrogen ions”) or “negative logarithm” (referring to the mathematical description of hydrogen ion concentration)
#3. To: buckeroo (#0)
#4. To: Pinguinite (#2)
I read the "p" stands for potential. High pH means it has high potential to absorb hydrogen.
#5. To: Shoonra (#3)
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