Tag Archives: marine

Ancient sharks reared young in prehistoric river-delta nursery

ANN ARBOR — Like salmon in reverse, long-snouted Bandringa sharks migrated downstream from freshwater swamps to a tropical coastline to spawn 310 million years ago, leaving behind fossil evidence of one of the earliest known shark nurseries.

That’s the surprising conclusion of University of Michigan paleontologist Lauren Sallan and a University of Chicago colleague, who reanalyzed all known specimens of Bandringa, a bottom-feeding predator that lived in an ancient river delta system that spanned what is today the Upper Midwest. (more…)

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UA Scientists Help Discover Most Abundant Ocean Virus

Researchers have discovered four previously unknown viruses that infect the Earth’s most abundant organism, the marine bacterium SAR11. Because of their huge numbers, these tiny players have critical roles in the global cycle of carbon and other nutrients.

The greatest battle in Earth’s history has been going on for hundreds of millions of years, isn’t over yet, and until now no one knew it existed, scientists reported today in the journal Nature.

In one corner is the Earth’s most abundant organism: SAR11, an ocean-living bacterium that survives where most other cells would die and plays a major role in the planet’s carbon cycle. It had been theorized that SAR11 was so small and widespread that it must be invulnerable to attack. (more…)

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NASA Radar Penetrates Thick, Thin of Gulf Oil Spill

PASADENA, Calif. – Researchers at NASA’s Jet Propulsion Laboratory and the California Institute of Technology in Pasadena have developed a method to use a specialized NASA 3-D imaging radar to characterize the oil in oil spills, such as the 2010 BP Deepwater Horizon spill in the Gulf of Mexico. The research can be used to improve response operations during future marine oil spills.

Caltech graduate student Brent Minchew and JPL researchers Cathleen Jones and Ben Holt analyzed NASA radar imagery collected over the main slick of the BP Deepwater Horizon oil spill on June 22 and June 23, 2010. The data were acquired by the JPL-developed Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) during the first of its three deployments over the spill area between June 2010 and July 2012. The UAVSAR was carried in a pod mounted beneath a NASA C-20A piloted aircraft, a version of the Gulfstream III business jet, based at NASA’s Dryden Aircraft Operations Facility in Palmdale, Calif. The researchers demonstrated, for the first time, that a radar system like UAVSAR can be used to characterize the oil within a slick, distinguishing very thin films like oil sheen from more damaging thick oil emulsions. (more…)

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Scientists Uncover Vast Differences in Earth’s Polar Ocean Microbial Communities

ANN ARBOR— An international team of scientists, including a University of Michigan graduate student, has demonstrated that a clear difference exists between the marine microbial communities in the Southern and Arctic oceans, contributing to a better understanding of the biodiversity of marine life at the poles.

The most comprehensive comparison of microbial diversity at both of Earth’s polar oceans showed that about 75 percent of the organisms at each pole are different. This insight sheds light on newly recognized biodiversity patterns and reinforces the importance of studying Earth’s polar regions in the face of a changing climate. And it highlights the need for further research on the impacts of sea ice, seasonal shifts and freshwater input in both regions. (more…)

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Scientists Explore Changing Arctic Ocean

Scientists are setting sail on August 25 to study ocean acidification in the Arctic and what this means for the future survival of marine and terrestrial organisms.

The Arctic Ocean is one of the most vulnerable places on the planet for acidification, yet it is the least-explored ocean. Acidification can disturb the balance of marine life in the world’s oceans, and consequently affect humans and animals that rely on those food resources.

Ocean acidification is particularly harmful to organisms such as corals, oysters, crabs, shrimp and plankton, as well as those up and down the food chain. Higher acidity decreases an organism’s calcification rate, meaning they lose their ability to build shells or skeletons. (more…)

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Ancient Alteration of Seawater Chemistry Linked With Past Climate Change

Dissolution or creation of huge gypsum deposits changed sulfate content of the oceans

Scientists have discovered a potential cause of Earth’s “icehouse climate” cooling trend of the past 45 million years. It has everything to do with the chemistry of the world’s oceans.

“Seawater chemistry is characterized by long phases of stability, which are interrupted by short intervals of rapid change,” says geoscientist Ulrich Wortmann of the University of Toronto, lead author of a paper reporting the results and published this week in the journal Science.

“We’ve established a new framework that helps us better interpret evolutionary trends and climate change over long periods of time. The study focuses on the past 130 million years, but similar interactions have likely occurred through the past 500 million years.” (more…)

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Slow Snails, Fast Genes: Predatory Snails Refine Venoms Through Continuous Gene Duplication

ANN ARBOR, Mich.— When tropical marine cone snails sink their harpoon-like teeth into their prey, they inject paralyzing venoms made from a potent mix of more than 100 different neurotoxins.

Biologists have known for more than a decade that the genes which provide the recipes for cone snail toxins are among the fastest-evolving genes in the animal kingdom, enabling these predatory gastropods to constantly refine their venoms to more precisely target the neuromuscular systems of their prey. (more…)

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High-Tech Software and Unmanned Planes Allow Scientists to Keep Tabs on Arctic Seals

A novel project using cameras mounted on unmanned aircraft flying over the Arctic is serving double duty by assessing the characteristics of declining sea ice and using the same aerial photos to pinpoint seals that have hauled up on ice floes.

The project is the first to use aircraft to monitor ice and seals in remote areas without putting pilots and observers at risk, said Elizabeth Weatherhead of the University of Colorado at Boulder, who is leading the study team. Weatherhead is a senior scientist at the Cooperative Institute for Research in Environmental Sciences, a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration. (more…)

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