Science Briefs

Forest elephants decimated

New data from the field in Central Africa shows that between 2002 and 2013, 65 percent of forest elephants were killed. They are being poached, for their ivory, at a shocking 9 percent per year.

The new data marks an update to an earlier paper in the online journal PLOS ONE on the status of forest elephants across Central Africa, published by the same scientists. Many organizations collaborated in the study, which covered 80 sites, in five countries, over the 12 years of data collection.

The earlier paper, published in 2013, already had shown a decline of 62 percent of the population between 2002 and 2011 – to less than 10 percent of its potential historical size, and that elephants occupied only a quarter of the forests where they once roamed.

The update, adding new data from 2012 and 2013, was released at the United for Wildlife symposium last week in London. Wildlife Conservation Society

Barley virus is 2,000 years old

Scientists have for the first time sequenced an ancient RNA genome – of a barley virus once believed to be only 150 years old – pushing its origin back at least 2,000 years and revealing how intense farming at the time of the Crusades contributed to its spread.

Researchers at Britain’s University of Warwick detected and sequenced the RNA genome of Barley Stripe Mosaic Virus (BSMV) in a 750-year-old barley grain found near the River Nile in modern-day Egypt. Their study, published in the journal Scientific Reports, challenges current beliefs about the age of the BSMV virus, which was first discovered in 1950 with the earliest record of symptoms just 100 years ago.

Although ancient DNA genomes have been sequenced before, ancient RNA genomes have not: RNA generally breaks down about 50 times as fast. But in extremely dry conditions, such as those at the site where the barley was found, RNA can be better preserved.

Using the new medieval RNA to calibrate estimates of the rate of mutations, the researchers were able to trace the evolution of this virus to a probable origin of about 2,000 years ago, but potentially much further.

Zebra mussels fuels algae blooms

Researchers at Michigan’s Grand Valley State University are learning more about the impact invasive zebra mussels and native aquatic insect larvae have on the risk of algae blooms. The results of the research will be published in the journal Oikos.

The study involved the impact that invasive zebra mussels and native chironomid larvae have on nutrient releases in two Michigan lakes. Researchers Geraldine Nogaro and Alan Steinman noted that filter feeding and excretion activity by invasive mussels stimulated nutrient releases in the water column. The other subject of their research was the impact of native chironomids, insect larvae that live in sediment on the lake bottoms.

“When nutrient levels increase, so does the risk of stimulated algae blooms,” Nogaro said. “The blooms are problematic because you can’t enjoy the lakes, and because certain blooms of cyanobacteria can release toxins into the water, which impacts fish and other wildlife.”

Nogaro also said bacteria growing on decomposing algae blooms can suck up valuable dissolved oxygen in the lake, which can result in large fish kills in the affected areas.

Identification ... by earwax?

Scientists from Philadelphia’s Monell Chemical Senses Center have used analytical organic chemistry to identify the presence of odor-producing chemical compounds in human earwax. They also found that the amounts of these compounds differ between individuals of East Asian origin and Caucasians.

The findings suggest that human earwax, an easily obtained bodily secretion, could be an overlooked source of personal information.

“Our previous research has shown that underarm odors can convey a great deal of information about an individual, including personal identity, gender, sexual orientation, and health status,” said study lead author George Preti, an organic chemist at Monell. “We think it possible that earwax may contain similar information.”

Earwax, scientifically known as cerumen, is a mixture of secretions from specialized sweat glands with fatty materials secreted from sebaceous glands. It can have one of two physical types: a wet yellow-brown wax or a dry white wax.