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New Sea Otter Scourge Found

                          July 01, 2004, Adapted by Megan Mansell Williams and Kathleen M. Wong,
                                                    California Academy of Sciences

Southern sea otters are dying from diseases carried by opossums as well as cats. The discovery, part of an ongoing study of sea otter mortality, may help scientists figure out how to stem the marine mammal's alarming decline. Last year was particularly rough on Southern California otters. In April 2003, sixty-two washed ashore dead, beating the one-month record of 42 deaths set the year before.

Wildlife veterinarian Melissa Miller of the Univeristy of California, Davis, determined each animal's cause of death. She found 11 were infected with Sarcocystis neurona, a parasite spread through opossum feces. Previously, Miller and colleagues had found otters dying of Toxoplasma gondii, a parasite found in cat feces. Both organisms attack the brain and nervous system.

Miller says the otter likely caught Sarcocystis neurona by eating contaminated shellfish. Runoff after rainstorms can carry infected feces into the ocean. The opossum parasite may be particularly lethal to sea otters because it is unfamiliar; opossums were introduced to California from Virginia in the 1900s.

Alaskan Earthquake Touches Yellow Geysers

An earthquake that rocked Alaska replumbed geysers as far away as Yellowstone National Park. The magnitude 7.9 quake, centered in Alaska's Denali National Park in November 2002, sparked a flurry of smaller earthquakes and erratic geyser behavior at Yellowstone, nearly 2, 000 miles away. The seismic rumbles set off eruptions in some geysers and quieted others.

This is the first time such a distant quake has been observed to cause major changes at geothermal hot spots, report park geologist Hank Heasler and colleagues in the journal Geology. The seismic ripples changed water pressures in the conduits beneath the geysers, causing some pipes to clog and others to gush. These pressure changes triggered  nearly 1, 000 small earthquakes at Yellowstone within a week of the Denali shaker.

Of the 22 geysers observed during that time, eight showed changes in their eruption behavior, but most resumed their usual behavior in the days and months after the quake.

Antarctic Snow Casts Doubt on a Coming Ice Age

Forget what you saw in the movie The Day After Tomorrow - a new ice age isn't dawning anytime soon. Currently, Earth in the midst of a warming period that began about 12, 000 years ago.

Because the three warming periods preceding this one lasted only about 10, 000 years, some have speculated that another ice age is long overdue. But according to a new study published in the journal Nature, Earth might be only midway through its current temperature phase.

After five years of drilling, scientists with the European Project for the Ice Coring were able to obtain Antarctic snow layers 10, 000 feet deep. The cores contain a record of climate conditions dating back 740, 000 years. By analyzing the hydrogen in the ice cores, the scientists determined that a warm period that peaked 430, 000 years ago endured for a whopping 28, 000 years. Climate data from that time is particularly relevant because Earth's orbital position, which influences the amount of sunlight it receives, was very similar to today's.

Only the Strongest New Galaxies Survive

The Milky Way is orbited by a dozen smaller galaxies - far fewer than current theories would predict. Now a new computer simulation run by Andrey Kravtsov and colleagues at the University of Chicago may explain why.

According to conventional theories, slow-moving dark matter, which makes up a good portion of the universe, slowly aggregates into clumps. Overtime, these clumps grow large enough to contain the normal matter needed to make stars and then galaxies. Kravtsov' team ran simulations of the formation of our galaxy in slow motion using small time increments.

This fine-grained analysis revealed that as gravity exerts its pull, the largest dark matter clusters actually pull mass away from the smaller ones, limiting their growth and shutting down star formation in these wimpy clumps. As  a result, the number of orbiting galaxies in Kravsov's model matches what actually exists. The team reposts its results in the The Astrophysical Journal.

Saturn's Moon Phoebe Unmasked

The Cassini space robe has obtained the closest look yet at Saturn's strange moon Phoebe. Images of the moon's battle-scarred surface should help astronomers pin down the rock satellite's origins.

A joint project on its way to a four-year orbit around Saturn. Images sent back over the weekend reveal deep craters, thin fissures, and chains of pits on Phoebe's surface, probably caused by many cosmic collisions. NASA scientists suspect that ice-rich Phoebe, which circles Saturn in the opposite direction of its 31 sister moons, formed in the outer solar system and was captured by Saturn early on.

Continuing data analysis of the Cassini images should reveal more in the coming weeks. The last time a craft was in the neighborhood was in 1981, when Voyager 2 passed within 1.4 million miles of the moon. Source.
 

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