Earth Changes

Pieces of debris collected by cleanup crews that are cleaning up the Padre Island National Seashore, Tuesday, Sept. 30, 2008, on South Padre Island, Texas. Debris from Hurricane Ike litters more than 60 miles of the national seashore.
Tons of debris swept up by Hurricane Ike last month were carried by Gulf of Mexico currents hundreds of miles from the upper Texas coast to this ordinarily pristine landscape just north of the Mexican border.
Sections of roofs, refrigerators, loveseats, beds, TVs, hot tubs and holiday decorations litter the more than 60 miles of gently arcing sand in the national park.
Some of the junk is good for a laugh, like the lifejacket-clad snowman someone placed next to a plastic pumpkin, a small but real palm tree and an acoustic guitar. But it's no joke to wildlife workers who are worried the trash will harm birds and other animals, including an endangered turtle that nests here in the spring.
The findings, based on a review of 872 published studies of 206 ocean-floor dwelling species, also suggest that a much greater area than we thought is dangerously low on oxygen.
In marine dead zones - also known as hypoxic zones - the amount of dissolved oxygen in the water becomes too low for organisms to survive.
They are usually caused by synthetic fertilisers, which are carried from fields, down rivers, and out to sea, where algal blooms gorge on the extra nutrients. When these phytoplankton die, they fall to the bottom where they are eaten by bacteria that consume all the local oxygen in the process.
Marine biologists generally hold that any area that has less than 2 milligrams of dissolved oxygen per litre of seawater is hypoxic - "dead". The threshold was set by a study in 1983 in the Gulf of Mexico, when marine biologists found that fish and shrimp had deserted bottom waters that had 2 mg/l of oxygen or less.
The findings could have implications for the management of what were once thought to be entirely distinct populations.
David Secor of the University of Maryland and colleagues looked at chemical signatures in the fish's inner ear to determine where each of the highly endangered fish came from.
Specifically, the team looked at a bone-like structure called the otolith, a calcium-carbonate deposit that is laid down after a fish hatches. These carry different concentrations of oxygen isotopes depending on whether the fish developed in cool Mediterranean waters - eastern bluefin - or warmer Gulf waters, which spawn western bluefin.

Pundamilia nyererei fish. Nuptial coloration in males of the cichlid species Pundamilia nyererei and Pundamilia pundamilia is adapted to the red or blue ambient light of their respective habitats and to the corresponding visual sensitivity of the females.
A study of brightly coloured fish has now demonstrated that this has less to do with aesthetics than with the sensitivity of female eyes, which varies as a result of adaptation to the environment. Females more attuned to blue will choose a metallic blue mate, while those better able to see red will prefer a bright red male. These mating preferences can be strong enough to drive the formation of new species - provided that habitat diversity is not reduced by human activities.

Small red cottage by a green summer meadow in Sweden. Researchers found much more plutonium in Swedish soil at a depth that corresponded with the Chernobyl nuclear explosion than that of Poland.
More than 20 years later, researchers from Case Western Reserve University traveled to Sweden and Poland to gain insight into the downward migration of Chernobyl-derived radionuclides in the soil. Among the team's findings was the fact that much more plutonium was found in the Swedish soil at a depth that corresponded with the nuclear explosion than that of Poland.
Radionuclides occur in soil both from natural processes and as fallout from nuclear testing.
Gerald Matisoff, chair of the department of geological sciences at Case Western Reserve University, Lauren Vitko, field assistant from Case Western Reserve, and others took soil samples in various locations in the two countries, measuring the presence and location of cesium (137Cs), plutonium (239, 240Pu), and lead (210Pbxs).
Until now, nobody knew how many oily compounds were being devoured by the microscopic creatures, but new research led by David Valentine of UC Santa Barbara and Chris Reddy of Woods Hole Oceanographic Institution in Massachusetts has shed new light on just how extensive their diet can be.
In a report to be published in the Oct. 1 edition of the journal Environmental Science & Technology, Valentine, Reddy, lead author George Wardlaw of UCSB, and three other co-authors detail how the microbes are dining on thousands of compounds that make up the oil seeping from the sea floor.
"It takes a special organism to live half a mile deep in the Earth and eat oil for a living," said Valentine, an associate professor of earth science at UCSB. "There's this incredibly complex diet for organisms down there eating the oil. It's like a buffet."

Tadpole in a pond. Routine pesticide use suggests that malathion -— the most popular insecticide in the United States —- can decimate tadpole populations by altering their food chain.
The results build on a nine-year effort by study author Rick Relyea, an associate professor of biological sciences in Pitt's School of Arts and Sciences, to investigate whether there is a link between pesticides and the global decline in amphibians, which are considered an environmental indicator species because of their sensitivity to pollutants. Their deaths may foreshadow the poisoning of other, less environmentally sensitive species - including humans. Relyea published papers in 2005 in Ecological Applications suggesting that the popular weed-killer Roundup® is "extremely lethal" to amphibians in concentrations found in the environment.
A second study by researchers at Florida Atlantic University recommends that the state of Florida adopt a series of policy programs aimed at adapting to these large coastal and other impacts as a result of climate change. Key findings of the FAU report were included just this week by Florida Gov. Charlie Crist's Climate and Energy Action Team when it adopted the "Adaptation" section of its final report.
"The impacts of climate change on Florida's coasts and on our economy will be substantial, persistent and long-term, even under our conservative estimates," said Julie Harrington, director of the Center for Economic Forecasting and Analysis at FSU. "Should, as many models predict, sea level rise, and hurricane strength and other factors become more extreme, much greater economic impacts will occur along many parts of Florida's coast in this century."
The second new study, by researchers at FAU, focused on state adaptation policies needed as Florida faces the impacts of climate change.
"The goal of our study is to help the state of Florida adapt, in the most effective way possible, to climate change impacts that are now inevitable," said Jim Murley, director of Florida Atlantic University's Center for Urban and Environmental Solutions and leader of the study. "These approaches must be comprehensive and strategic, not piecemeal and episodic. Governor Crist and other leaders have rightly identified adapting to climate change as one of the state's greatest challenges -- we look forward to working with the state to protect our people, natural splendor, and economic livelihood. There is real work to be done."