Coastal upwelling fisheries
This graphic shows how displaced surface waters are replaced by cold, nutrient-rich water that “wells up” from below.
Winds blowing across the ocean surface push water away. Water then rises up from beneath the surface to replace the water that was pushed away. This process is known as “upwelling.”
Upwelling occurs in the open ocean and along coastlines. The reverse process, called “downwelling, ” also occurs when wind causes surface water to build up along a coastline and the surface water eventually sinks toward the bottom.
Water that rises to the surface as a result of upwelling is typically colder and is rich in nutrients. These nutrients “fertilize” surface waters, meaning that these surface waters often have high biological productivity. Therefore, good fishing grounds typically are found where upwelling is common.
For more information: Pacific Fisheries Environmental Laboratory
Over-fishing spell disaster for oceans2008-04-10 23:46:07 by badspellernocaps
The future food security of millions of people is at risk because over-fishing, climate change and pollution are inflicting massive damage on the world's oceans, marine scientists warned this week.
The two-thirds of the planet covered by seas provide one fifth of the world's protein -- but 75 percent of fish stocks are now fully exploited or depleted, a Hanoi conference that ended Friday was told.
Warming seas are bleaching corals, feeding algal blooms and changing ocean currents that impact the weather, and rising sea levels could in future threaten coastal areas from Bangladesh to New York, experts said
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