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(单词翻译:双击或拖选)
Every spring, the Mississippi River dumps tens of thousands of tons of nutrient1 runoff into the Gulf2 of Mexico. Add temperature, current and wind to that pollution, and you have the Western Hemisphere's largest stretch of oxygen-poor waters—a so-called "dead zone."
That dead zone hits the Gulf's famed—and financially important—brown shrimp3 fisheries. And it does two things: first, the low oxygen slows down the shrimps’ growth.
"The other thing that occurs is what I like to call the burning building effect." Martin Smith, an environmental economist4 at Duke University. "The shrimp try to avoid the low oxygen so they swim out of these areas of depleted5 oxygen. As a result they end up kind of aggregating6 on the edges. They kind of line up outside the deoxygenated waters. And that's why I call it the burning building effect. If you're in a burning building you're running to get out of the fire, you don't keep running when you get outside, you stop and you take a breath."
Fishermen flock to where those shrimp "take a breath." And shrimp get caught earlier in the season. So combine these two effects—slower growth and earlier catches—and the result is a haul of more small shrimp, and fewer large and jumbo shrimp. Meaning the price on big shrimp temporarily goes up. Supply and demand, right?
Smith and his team studied that link—between the dead zone and a spike7 in large shrimp prices—using 20 years of shrimp pricing data. Their analysis is in the Proceedings8 of the National Academy of Sciences. [Martin D. Smith, Seafood9 prices reveal impacts of a major ecological10 disturbance]
The brown shrimp fishery in the Gulf was once the most valuable in the U.S. Now, Smith says, we can measure the true cost of that nutrient runoff. "We can start to ask questions like, how much does the shrimp industry lose as a result of this problem, and how does that compare to what it would cost to control nutrient flows coming from food prediction upstream in the Mississippi watershed11?" In other words—whether there might be some net economic benefit to keeping the water environmentally protected.
—Christopher Intagliata
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1
nutrient
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adj.营养的,滋养的;n.营养物,营养品 | |
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2
gulf
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n.海湾;深渊,鸿沟;分歧,隔阂 | |
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3
shrimp
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n.虾,小虾;矮小的人 | |
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4
economist
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n.经济学家,经济专家,节俭的人 | |
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5
depleted
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adj. 枯竭的, 废弃的 动词deplete的过去式和过去分词 | |
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6
aggregating
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总计达…( aggregate的现在分词 ); 聚集,集合; (使)聚集 | |
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7
spike
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n.长钉,钉鞋;v.以大钉钉牢,使...失效 | |
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8
proceedings
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n.进程,过程,议程;诉讼(程序);公报 | |
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9
seafood
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n.海产食品,海味,海鲜 | |
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10
ecological
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adj.生态的,生态学的 | |
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11
watershed
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n.转折点,分水岭,分界线 | |
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