Great white sharks — one of the ocean’s most fearsome predators — thrive with toxic levels of poisons flowing in their veins, said a study by OCEARCH, a nonprofit. It said it could be one of the tricks that the species has used to survive millions of years. Samples taken from 40 white sharks off South Africa revealed “alarmingly high levels of poisonous heavy metals, like arsenic and mercury, in sharks’ blood,” the report said. “Despite levels of heavy metals that would be toxic to most other species, white sharks seem to show no ill effects.” Liza Merly of the Rosenstiel School of Marine and Atmospheric Science said the research could benefit humans, when researchers figure out the “protective mechanism” in sharks that protects them from the toxins. However, for now, the study’s co-author warned, “If the sharks have high levels of toxins in their tissues, it is likely that species they eat below them will also have toxins, including fishes that humans eat.”

Remnants of planet orbits ex-star

In a shard of galactic archaeology that offers a less-than-inviting hint at our own future, astronomers have discovered a chunk of a former planet orbiting the remains of its former star, now a smoldering cinder known as a white dwarf. The fragment, made mostly of iron, nickel and other metals, lies 410 light-years from Earth in the constellation Virgo. It could be a mile, or hundreds of miles, in diameter, but to be dense enough to have survived the explosive demise and subsequent evolution of its host star, it was most likely part of a large planet with a wider, more distant orbit. Now it circles the white dwarf so closely that it completes an orbit every 123 minutes. “The fact that we have discovered a body orbiting on a two-hour period is clear evidence that a planetary body can survive this destructive process,” said Christopher Manser, a physicist at the University of Warwick in England and leader of an international team that reported the results in Science.

How underwater beetles breathe

The tiny swimming beetles of the Australian desert live circumscribed lives. Denizens of a series of underground, water-filled chambers, they rarely, if ever, get to the surface. But how are they breathing? Other water-dwelling beetles capture an air bubble beneath their wings before they dive, which they use like a scuba tank. Or, they have special hairlike structures that let them eke out their own air supply underwater. Scientists who have taken a close look at these Australian beetles, however, reported in the Journal of Experimental Biology that the insects use neither of these approaches. Instead, they appear to siphon oxygen directly from the water, breathing, in essence, with their skin. The researchers found that these beetles have markedly thin cuticles compared with their surface-dwelling brethren, which would make it easier for oxygen to diffuse through it.

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