Ancient oceans: a saltier time

Seawater retrieved from a crater deep under Chesapeake Bay is 100 million to 145 million years old, researchers say, offering a rare glimpse of ancient ocean conditions in the North Atlantic.

The water, pumped from the 35-million-year-old meteor impact site in 2005 during a deep drilling project, has an average salinity about twice that of the modern ocean, according to a study published in the journal Nature.

That level of salinity makes sense, given the state of the North Atlantic at the time the water was trapped. During the early Cretaceous period, the North Atlantic was in transition from a closed basin to an open ocean as North America and Africa moved farther apart.

“Those are the types of conditions that actually lead to high salinity,” said Ward Sanford, a research hydrologist with the U.S. Geological Survey and an author of the study. “In places like the Dead Sea, it’s completely enclosed and you have elevated salinity.”

“Generally there’s not a lot of information on the oceans way back because we don’t have any sample of the ocean water,” Sanford said.

Sanford says there is probably more preserved water in the Chesapeake site and other deep places along the East Coast, but excavating it will be hard and costly.

Men can be such worms and vice versa

Studies have repeatedly shown that married people live longer. But not if you’re a roundworm: Having a man around can kill you. Male roundworms secrete signaling molecules that significantly reduce the life span of the opposite sex, according to a new study from Stanford University School of Medicine. The findings, published in the journal Science, confirm previous observations that the presence of male worms or flies correlates with shorter lives for their female and hermaphroditic counterparts.

Among common laboratory roundworms, or C. elegans, a species consisting of males and hermaphrodites only, the continuous presence of a young male resulted in a 20 per cent shorter life span for all nonmales, the researchers found. Even placing hermaphrodites on plates that had previously held males was enough to reduce their life span.

“We really think that it is actually linked to copulation, because the primary goal of this worm is to copulate,” said Anne Brunet, a Stanford professor of genetics and an author of the study. C. elegans typically live for about 20 days.

Eliminating his partner after reproduction may serve several evolutionary objectives for the male worm, said the researchers, such as preserving resources for the offspring and draining the mating pool for other males.

Such behaviour is unlikely to extend to mammals, the researchers said. They rely on the mother to care for the offspring.

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