February 06, 2019
Microplastics are being discover in the unlikeliest of places - marine mammals. This shocking discovery was made during a recent survey. Truly horrible and distressing.
Learn about this and more interesting stories from the scientific community in today's issue.
Until Next Time,
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*-- Scientists in Britain found microplastics in every marine mammal they examined --*
Researchers at the University of Exeter found microplastics in all 50 animals they studied in a recent survey of beached marine mammals, including 10 species of dolphins, seals and whales.
Synthetic fibers constituted the majority of plastic debris recovered from the animals, strands from clothes, fishing nets and toothbrushes. One quarter of the animals contained plastic fragments, likely from food packaging and plastic bottles.
"It's shocking -- but not surprising -- that every animal had ingested microplastics," lead author Sarah Nelms, researcher at Exeter and the Plymouth Marine Laboratory, said in a news release.
Because scientists found relatively low concentrations of microplastics in the marine mammals, scientists think most of the debris would have eventually passed through their intestines or been regurgitated. But that doesn't mean the pollution can't harm large animals.
"We don't yet know what effects the microplastics, or the chemicals on and in them, might have on marine mammals," Nelms said. "More research is needed to better understand the potential impacts on animal health."
Autopsies showed the beached animals died for a variety of reasons. Those that died from infectious disease hosted slightly higher concentrations microplastics, suggesting the debris could hamper the mammals' immune systems. But scientists say more research is needed to confirm such a link.
"We are at the very early stages of understanding this ubiquitous pollutant," said Brendan Godley, researcher at Exeter's Center for Ecology and Conservation. "We now have a benchmark that future studies can be compared with."
The new study -- published this week in the journal Scientific Reports -- isn't the first to reveal the ubiquity of microplastics in the guts of marine species, but it's worrisome news, nonetheless.
"Marine mammals are ideal sentinels of our impacts on the marine environment, as they are generally long lived and many feed high up in the food chain," Godley said.
*-- Scientists use rover's navigational sensors to measure Mars' gravity --*
Scientists were able to map Mars' gravity by repurposing data collected by the Curiosity rover's navigational sensors.
After realizing Curiosity's accelerometers can be used like gravimeters when the rover is at a standstill, scientists surveyed navigational data collected during the mission's first five years. Researchers were able to plot changes in the Red Planet's gravity along the path the rover took as it ascended Mount Sharp.
The new gravity data allowed scientists to estimate the density of the underlying rock along the rover's route. Gravity is weaker on the slopes of Mount Sharp than scientists expected, suggesting the sedimentary rock that forms the mountain isn't all that dense.
"The lower levels of Mount Sharp are surprisingly porous," Kevin Lewis of Johns Hopkins University said in a news release. "We know the bottom layers of the mountain were buried over time. That compacts them, making them denser. But this finding suggests they weren't buried by as much material as we thought."
Martian probes have previously mapped Mars' gravity fields, but not with the precision offered by super sensitive on-the-ground instruments. After calibrating the rover's data -- accounting for the influence of temperature and the rover's shifting axis tilt on Mount Sharp's uneven terrain -- scientists compared the improvised gravimeter observations with gravity field maps. The data was in agreement.
Mount Sharp rises 18,000 feet from the bottom of Gale Crater, an impact crater formed by a meteor that struck Mars between 3.5 billion and 3.8 billion years ago. Scientists are still unsure how exactly Mount Sharp formed, but the latest data -- published in the journal Science -- suggests at least one popular theory is flawed.
Some scientist hypothesize the crater was once completely filled with sediment. Over time, wind eroded large amounts of sediment, leaving behind Mount Sharp. But all that heavy sediment would have compacted the bottom layers of Mount Sharp.
"The low density of rocks in Gale Crater suggests that they did not undergo deep burial," said Nicholas Schmerr, an assistant professor of geology at the University of Maryland. "This could mean that Mount Sharp was not excavated by erosion, but rather was constructed by wind deposition and other processes."