Wednesday, March 12th, 2008
Is it important that global warming turns fish deaf? Yes. For coral reef fish, sound is vital for them to judge where to settle down and live.
After hatching, reef fish larvae are dispersed by ocean currents for a few weeks. The larval fish must then find their way back to a suitable reef to make their home.
It's thought that the young fish home in on high-frequency noises. Coral reefs are extremely noisy environments, with the crackle of snapping shrimps and the chatter of fish set against a backdrop of wind, rain and surf. Sound carries well underwater, and most fish have great hearing.
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Monday, March 10th, 2008
The skin of sea cucumbers was the inspiration for a new material that can change dramatically from rigid to floppy when soaked in water. Sea cucumbers' skin is usually supple, allowing them to slide through narrow spaces between rocks and corals. But when touched a defensive reaction makes their skin go rigid in seconds, thanks to enzymes that binds protein fibres together. A second set of enzymes can break those bonds to make the skin soft again.
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Friday, March 7th, 2008
Going deaf is not a problem that most of us would automatically associate with global warming. For coral reef fish, however, hotter seas could pose a real threat.
Young coral reef fish with misshapen ear bones are more likely to get lost and die, and exposure to warmer waters makes the problem worse, according to a study of fish living around Lizard Island on the Great Barrier Reef, Australia.
After hatching, most reef fish spend a few weeks out in the open ocean before returning to the reef to settle down. And it seems that sound is a key factor in guiding them to the right habitat.
The young fish have to home in on the high-frequency noises made by invertebrates like shrimp and sea urchins, and avoid the low-frequency noises made by crashing waves and adult fish.
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Thursday, March 6th, 2008
Here's another reason for retailers to charge for plastic bags. The swirling debris of plastic trash in the Pacific Ocean has now grown to a size that is twice as large as the continental US, according to the Alguita Marine Research team.
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Wednesday, March 5th, 2008
More than 40 percent of the world's oceans are heavily affected by human activities, and few if any areas remain untouched, according to the first global-scale study of human influence on marine ecosystems.
By overlaying maps of 17 different activities such as fishing, climate change and pollution, the researchers have produced a composite map of the toll that humans have exacted on the seas.
The study reports that the most heavily affected waters in the world include the Caribbean Sea, the Mediterranean Sea, the Red Sea and several regions in the western Pacific. The least affected areas are largely near the poles.
Human influence on the ocean varies dramatically across various ecosystems. The most heavily affected areas include coral reefs, rocky reefs and seamounts. The least impacted ecosystems are soft-bottom areas and open-ocean surface waters.
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Tuesday, March 4th, 2008
The same chemicals that keep food from sticking to our frying pans and stains from setting in our carpets are damaging the livers and impairing the immune systems of loggerhead turtles - an environmental health impact that also may signal a danger for humans.
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