glaciology

washingtonpost.com
Scientists confirm that warm ocean water is melting the biggest glacier in East Antarctica
Scientists have now put together all the pieces to confirm that the enormous Totten glacier is losing mass rapidly, and the ocean is responsible.
By https://www.facebook.com/chriscmooney

These waters, the paper asserts, are causing the ice shelf to lose between 63 and 80 billion tons of its mass to the ocean per year, and to lose about 10 meters (32 feet) of thickness annually, a reduction that has been previously noted based on satellite measurements.

This matters because more of East Antarctica flows out towards the sea through the Totten glacier region than for any other glacier in the entirety of the East Antarctic ice sheet. Its entire “catchment,” or the region of ice that slowly flows outward through Totten glacier and its ice shelf, is larger than California. If all of this ice were to end up in the ocean somehow, seas would raise by about 11.5 feet.

“This ice shelf is thinning, and it’s thinning because the ocean is delivering warm water to the ice shelf, just like in West Antarctica,” said Don Blankenship, a glaciologist at the University of Texas at Austin and one of the study’s co-authors. Blankenship was not on the research vessel, but he and his colleagues helped the Australia-based researchers with understanding the contours of the seafloor so they could plan their field investigations into where warm and deep waters could penetrate.

medium.com
Meet 12 Badass Scientists…Who Also Happen to be Women — TED Fellows
What do you see when you picture a scientist? Is it a white man in a lab coat? This portrait will smash that stereotype …
By Karen Eng

“This week, a cab driver asked me, ‘What do men say when you tell them you’re a scientist? Because you don’t look like a scientist,’” marine biologist Kristen Marhaver says. “In this picture, I see a twinkle in each of our eyes, saying, ‘No, that’s the thing, sir. I do look like a scientist.’”

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It’s raining today ♡ But I’m glad because I finished my projects ! All of them ! Now I have a week and a half to write my report, so I made a list to have a little work everyday. I wanted to start writing but I have to write in french and the keyboard is qwerty, and I don’t have any “accents” ahah 😂 Work well, study well, relax whatever, I hope you’ll have a nice day :) ♡

Aeolian loess drift, Alaska.

Loess

* when Glaciers run across land they drag lots of underground material with them, such as rocks and soil

* over time they erode that material into smaller, finer pieces, even finer than sand: silt. 

* parts of the glaciers melt: through the glacier mouth ‘milky’ melt water flows out with the suspended load 

* once the glacier oscillates the aera becomes a periglacial zone

* due to extrem coldness no vegetation is around and the dryness prevents the silt particals from sticking together

-> through aeolian deflation the silt travels and is then called Loess.

* Properties: makes the ground really fertile, is very susceptible to hyrdo-erosion

Photo: NASA / Jeff Schmaltz / MODIS / Goddard Space Flight Center 

Everything, It Appears, Is Not Everywhere

What lies beneath? The rules governing microbial diversity in the world’s oceans are still largely unknown. (Photo credit: Flickr/Rita Willaert)

The world’s oceans are biological soups, repositories of unseen, single-celled organisms that dominate the planet’s nutrient cycles and dictate its atmospheric composition. But given how important these microbes are to a functioning planet-wide ecosystem – and the rapid rate of environmental changes currently being inflicted upon such ecosystems – we know dangerously little about how community structure works. Why are certain organisms where they are, and what are the consequences of their distributions?

These are the guiding questions for microbial ecologists as they attempt to understand how single-celled organisms are distributed across our planet. It’s a daunting task, and with an estimated 3.6 x 1030 cells in the ocean to catalog, it would be helpful if more generalized rules of diversity could be developed. That way, you could collect basic data from your environment of interest – temperature, chemical concentrations, or ocean current speeds, for example – toss them into your unified theory of diversity, and produce a reliable description of numbers, types, and behaviors of likely microbial constituents.

Of course, it’s never going to be quite that easy; many of the fundamental tenets of microbial diversity are still very much up for debate. A recent study by Woo Jun Sul and his colleagues at the Marine Biological Laboratory represents a key result in the continued refinement of these generalized rules.

One of the most enduring principles of microbial ecology over the years has been Dutch scientist Lourens Baas Becking’s oft-cited (and oft-mistranslated) pronouncement that “everything is everywhere, but the environment selects.” It’s a pretty self-explanatory hypothesis, reflecting the notion that microbial species are not limited by dispersion, and that a site’s species profile results from winnowing down a comprehensive list of organisms based on environmental parameters. In other words, the reason we don’t see psychrophilic (cold-loving) microbes inside hydrothermal vent chimneys isn’t because they can’t get there, but rather because they can’t handle the heat.

Sul examined the Bass Becking hypothesis by comparing a null model in which there were no checks on dispersal with actual data gleaned from the International Census of Marine Microbes project. 4.23 million microbial gene sequences from 277 sites across the world’s oceans clustered into 65,545 distinct bins of diversity, forming the basis for one of the few rigorous looks at large-scale diversity gradients.

Next, the researchers examined the overlap in microbial community structure at increasingly distant, increasingly selective habitats. If Bass Becking holds, they contend, then organisms well suited to a demanding environment would have the same universal access to it regardless of its distance from a similar, already-colonized site. Instead, they found that the communities diverged as the distance between the sites increased, suggesting that something is inhibiting global dispersal forces.

Among other findings, the report also shows that the diversity of marine waters decreases as you move pole-ward from the equator. But, Sul writes, the trend of this decrease is more severe in the southern hemisphere than in the north, “suggesting that the tropics may serve as a barrier to bacterial dispersal.”

The team concludes that, in addition to environmental factors, dispersion limiting factors like constrained ocean currents and “physical barriers such as the landlocked nature of the Arctic Ocean” play key roles in governing microbial diversity.

Sul’s revised proclamation: “everything is not everywhere, and the environment selects.”

果然读书时间过得快,只是大一时电脑中的存档多已不在,不然还可多爬梳一些资料。

想起两年前,跟同学聚餐时,说起未来想去研究Glaciology。两年过后,诸事不由己,我也不清楚自己终身志业是什么。

random cool science fact of the day!!!!!

THIS:

External image

IS A TUYAits a volcano that exists under a glacier!!!!!!!!!! its distinctively flat-topped, pretty isolated shape makes it very recognizable and very cool!!!!!!

its formed when a volcano erupts under a glacier and the eruption either melts all the ice or it punches right through it. the basalt flows on top of the hill, causing the distinctive flatness. they’re pretty rare, but are really useful in constructing histories of glaciations over millions of years!!!!