Science Sunday: Wrong Fish, Looks Still Count, and Acid Oceans


Greenback cutthroat trout. Really. Photo by Colorado Division of Wildlife
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A decades long effort to prevent the extinction of the threatened greenback cutthroat trout in Colorado are in danger because — drumroll, please — biologists have inadvertently restored the wrong species.

University of Colorado-Boulder scientists, led by biologist Jessica Metcalf, conducted sophisticated genetic testing on greenback cutthroat and a closely related species, the Colorado River cutthroat trout.

“The new study, which included sequencing and analyzing mitochondrial and nuclear DNA, showed the majority of the greenback populations had been misidentified, and that the greenback cutthroat trout range is now restricted to just 11 miles of streams in several remote areas of Colorado.”

Instead of being reestablished in several areas of the state, the greenback cutthroat trout is now restricted to only 11 miles of stream in several remote areas of the state.

Although greenback cutthroats were declared extinct in 1937 — victims of mining pollution, fishing pressure and competition from other trout species — several small populations were discovered in tributaries to the Arkansas River and South Platte River drainages in the 1950s, she said. Greenback cutthroats were added to the federal list of endangered species in 1978.”

The scientist who have been pursuing this effort are not really to blame for the confusion, however. Many fish species were delivered to local communities by the railroads in the late 1800s and early 1900s for stocking of streams. The eggs and sperm believed to be pure greenback cutthroat trout at the time the effort got under way were probably contaminated by these introduced species. “We have to remember that management decisions by federal and state fisheries biologists over the past decades were based on the best reports available by experts at the time,” Metcalf says.

The research was published in the Aug. 28 online edition of the journal Molecular Ecology.

Acid ocean

Human alteration of the nitrogen and sulfur content of the atmosphere is changing ocean water chemistry, resulting in acidification of the oceans. Although the average increase in acidification over the whole ocean is small, the impact can be substantial in coastal waters.

Work published in this week’s Proceedings of the National Academy of Sciences by a team that includes Boulder’s National Center for Atmospheric Research Meteorologist Natalie Mahowald, found:

“Although there are certainly caveats with the simulated coastal signals because the global ocean model does not fully resolve complex coastal physical and biological dynamics, the coastal amplification is clear. Ocean acidification is thought to be a significant threat to ecosystems, including coral reefs and coastal benthic and planktonic food webs dominated by calcifying organisms.

Globally, human burning of fossil fuels and biomass produce more nitrogen oxides, sulfur dioxide and ammonia than are produced by natural processes. In the atmosphere, these are are changed into nitric acid and sulfuric acid, which are then fall to earth as rain and snow. Most of the deposition is down wind from the world’s major industrial regions.

The process has been much publicized as acid rain’s impact on freshwater lakes, but less is known about the effect of this acidification on the oceans.

Me Tarzan, You Jane

Despite what they might say, mean want beauty in a mate, and women want security and commitment, according to research conducted in Germany by Indiana University scientists.

Cognitive scientist Peter Todd and colleagues found that beauty is the key ingredient in mate choice for men while women, the choosier of the two sexes (who knew?) “leverage their looks for security and commitment.”

The researchers studied a “speed dating” situation in Germany where men and women have “mini dates” lasting three to five minutes with as many as 30 different people. The researchers then had the participants answer questions.

“Not surprisingly,” Todd said, “participants stated they wanted to find someone who was like themselves — a socially acceptable answer. But once the sessions began, the men sought the more attractive women and the women were drawn to material wealth and security, setting their standards according to how attractive they viewed themselves. Furthermore, while men on average wanted to see every second woman again, the women wanted to meet only a third of the men again.”

The research appeared in the Proceedings of the National Academy of Sciences for the week of Sept. 4-7.