Friday, 25 May, 2012

As Asian carp approach the Great Lakes, ecologists seek to forestall a devastating invasion. Electric fish barriers on Chicago’s canals — built to dump wastewater into the Mississippi — are blocking carp from reaching Lake Michigan. Many scientists prefer closing the canals, but the shipping industry objects. Who’s right?

The ocean’s most valuable fish are caught in a vise. Areas known as dead zones are encroaching on their living zones and pinning them closer to the surface, where they are more vulnerable to becoming the day’s catch. The predicament is yet another side effect of climate change.

Fish contamination was rare after the giant oil spill in the Gulf of Mexico in 2010, with levels of dangerous hydrocarbons well below “levels of concern.” But nobody looked systematically at heavy metals, the Gulf still has a lot of oil, and the many different hydrocarbons may have unpredictable impacts.

Most of our planet is ocean, and now we have a better idea of what lives there. Marine creatures are much weirder than those on land. The Census of Marine Life looked at salmon migration, Arctic animals, and the uncountable variety of bacteria in the sea. Want to take a look?

Can we fix rivers? Dams, levees, and locks can harm rivers and wetlands. So can draining rivers dry, or encasing them in concrete. In a few places, conservationists are finding smarter ways to manage rivers and wetlands. Is a win-win solution possible for our wicked water woes?

When chemicals in the water trigger the endocrine system, male fish can start looking and acting female. What happens once chemicals from plastics, drugs and our own endocrine system are flushed down the toilet? Can we prevent them from entering our streams and harming wildlife?

Cleaner fish remove parasites from other fish. Why do males punish females who eat the wrong food from their host? A clue to the evolution of cooperation?

A new study finds a surprising number of fish, birds and mammals in the oceans 100 and 1,000 years ago. Can this information help regulators slow the decline of important marine animals?

Three giant new reserves, extend 50 miles out from shore, will protect coral reefs, fish, clams, and other life forms. But how effective are marine protected areas?

When too much fertilizer reaches the Gulf of Mexico through the Mississippi River, a vast area gets robbed of oxygen. What can be done to reduce the dead zone that appears each summer?