Inferring the Functions of Microbial Communities
Single celled prokaryotic microbes, such as bacteria and archaea, control almost every aspect of our daily lives, from our individual health to the elemental cycles that maintain the global biosphere. A major challenge for microbial ecologists is cataloging the vast diversity of prokaryotic life on Earth and connecting this diversity with specific functions, such as the production of an essential nutrient or a key biogeochemical transformation. While modern gene sequencing techniques make it possible to evaluate the diversity of prokaryotic communities at a high level of detail, the extension of this technology to sequencing complete community genomes, termed metagenomes, is costly and data intensive. Working with Hugh Ducklow in the Biology and Paleo Environment Division of the Lamont-Doherty Earth Observatory at Columbia University, BMSIS researcher Jeff Bowman recently published a new method for inferring community function from the diversity of a prokaryotic community. Although conceptually similar to existing tools for metabolic…
Ice ages in the Southern Hemisphere are influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit
A new international study casts doubt on the leading theory of what causes ice ages around the world — changes in the way the Earth orbits the sun. The researchers found that glacier movement in the Southern Hemisphere is influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit, which are thought to drive the advance and retreat of ice sheets in the Northern Hemisphere. The findings appear in the journal Geology. The study raises questions about the Milankovitch theory of climate, which says the expansion and contraction of Northern Hemisphere continental ice sheets are influenced by cyclic fluctuations in solar radiation intensity due to wobbles in the Earth’s orbit; those orbital fluctuations should have an opposite effect on Southern Hemisphere glaciers. “Records of past climatic changes are the only reason scientists are able to predict how the world will change in the…
Convergent evolution in land to sea transitions in marine predators across major mass extinctions
For more than 250 million years, four-limbed land animals known as tetrapods have repeatedly conquered the Earth’s oceans. These creatures–such as plesiosaurs, penguins and sea turtles–descended from separate groups of terrestrial vertebrates that convergently evolved to thrive in aquatic environments. In a new scientific review, a team of Smithsonian scientists synthesized decades of scientific discoveries to illuminate the common and unique patterns driving the extraordinary transitions that whales, dolphins, seals and other species underwent as they moved from land to sea. Drawing on recent breakthroughs in diverse fields such as paleontology, molecular biology and conservation ecology, their findings offer a comprehensive look at how life in the ocean has responded to environmental change over time. The paper also highlights how evolutionary history informs an understanding of the impact of human activities on marine species today. More information is available in the April 17 issue of Science. Marine tetrapods represent a…
New meltwater is not likely to further lubricate the Greenland Ice Sheet waterslide
Surface meltwater regularly travels to the bottom of the Greenland Ice Sheet and lubricates the flow of the ice into the ocean, but new research indicates that future increasing volumes of this meltwater are unlikely to speed the flow of the ice sheet. How is the Greenland Ice Sheet like an oil drill site? They both host the process of fracking, which is the use of high-pressure fluid to enhance existing cracks. In an oil field, high-pressure drilling fluid widens and deepens cracks in oil-bearing rocks, opening access to more deeply buried fossil fuels. On the Greenland Ice Sheet surface, meltwater fills cracks in the ice. Water is more dense than ice, which creates pressure that pries the cracks open. If there is enough water, a crack can reach the bottom of the ice sheet, opening a path for surface water to flow down to the bottom of the ice…
Abnormally high plume observed above surface of Mars
Plumes seen reaching high above the surface of Mars are causing a stir among scientists studying the atmosphere on the Red Planet On two separate occasions in March and April 2012, amateur astronomers reported definite plume-like features developing on the planet. The plumes were seen rising to altitudes of over 250 km above the same region of Mars on both occasions. By comparison, similar features seen in the past have not exceeded 100 km. “At about 250 km, the division between the atmosphere and outer space is very thin, so the reported plumes are extremely unexpected,” says Agustin Sanchez-Lavega of the Universidad del País Vasco in Spain, lead author of the paper reporting the results in the journal Nature. The features developed in less than 10 hours, covering an area of up to 1000 x 500 km, and remained visible for around 10 days, changing their structure from day to…
Is the mind algorithmic? Confusing science speak with layman language
“Evolution is just a theory.” This claim, often made by creationists, is clearly based on a confusion of the scientific meaning of the word “theory” with its meaning in common language. We can forgive confused creationists, though, as most of them unfortunately know very little about science (all the more important it is for us to explain our research in a clear way). However, when scientists themselves make such mistakes, perhaps we should be less forgiving. In science, a theory is a well-established body of knowledge about a certain subject, supported by observable facts, repeatable experiments, and logical reasoning. However, in common language the word “theory” is often used to mean “hypothesis”, “proposition”, or even “speculation” (indeed, these synonyms are all listed in the dictionary). Darwin’s theory of evolution is scientifically well-established (it has been so for more than a century), and is definitely more than “just a hypothesis.” It…
Can cold-loving bacteria help to clean up oil spills?
For several decades scientists have been interested in the ability of psychrophilic (cold- loving) microbial communities to degrade the various components of crude oil, which is a process known as bioremediation. Because temperature has a direct impact on enzyme activity there is a concern that, at very low temperatures, the microbial community might be inhibited in its ability to undertake bioremediation. The benefits of bioremediation were seen in the response of the microbial community during the infamous Deepwater Horizon event in the Gulf of Mexico. Indigenous bacteria deep in the water column consumed much of the escaping oil before it had the opportunity to reach the surface, lowering (but not eliminating) the ecological impact of that disaster. Despite the subtropical location of the Deepwater Horizon, the water temperature where much of this bioremediation took place is only 5 degrees Celsius. This is not much warmer than summertime Arctic surface waters…
Stray stars between galaxies add to the cosmic light in the universe
Using an experiment carried into space on a NASA suborbital rocket, astronomers at Caltech and their colleagues have detected a diffuse cosmic glow that appears to represent more light than that produced by known galaxies in the universe. The researchers, including Caltech Professor of Physics Jamie Bock and Caltech Senior Postdoctoral Fellow Michael Zemcov, say that the best explanation is that the cosmic light — described in a paper published November 7 in the journal Science — originates from stars that were stripped away from their parent galaxies and flung out into space as those galaxies collided and merged with other galaxies. The discovery suggests that many such previously undetected stars permeate what had been thought to be dark spaces between galaxies, forming an interconnected sea of stars. “Measuring such large fluctuations surprised us, but we carried out many tests to show the results are reliable,” says Zemcov, who led…
Combining fields of sustainability and astrobiology to probe human civilization longevity
Human-caused climate change, ocean acidification and species extinctions may eventually threaten the collapse of civilization, according to some scientists, while other people argue that for political or economic reasons we should allow industrial development to continue without restrictions. In a new paper, two astrophysicists argue that these questions may soon be resolvable scientifically, thanks to new data about the Earth and about other planets in our galaxy, and by combining the earth-based science of sustainability with the space-oriented field of astrobiology. “We have no idea how long a technological civilization like our own can last,” says University of Rochester astrophysicist Adam Frank. “Is it 200 years, 500 years or 50,000 years? Answering this question is at the root of all our concerns about the sustainability of human society.” “Are we the first and only technologically-intensive civilization in the entire history of the universe?” asks Frank. “If not, shouldn’t we stand…
Winter birds are more diverse thanks to warming climate
Climate change alters cast of winter birds MADISON — Over the past two decades, the resident communities of birds that attend eastern North America’s backyard bird feeders in winter have quietly been remade, most likely as a result of a warming climate. Writing this week in the journal Global Change Biology, University of Wisconsin-Madison wildlife biologists Benjamin Zuckerberg and Karine Princé document that once rare wintering bird species are now commonplace in the American Northeast. Using more than two decades of data on 38 species of birds gathered by thousands of “citizen scientists” through the Cornell University Laboratory of Ornithology’s Project FeederWatch, the Wisconsin researchers show that birds typically found in more southerly regions are gradually pushing north, restructuring the communities of birds that spend their winters in northern latitudes. To the causal observer of backyard birds, the list of species becoming more common includes the readily familiar: cardinals, chipping…
When the Bangladesh people think the monsoon starts
You might expect that a term like “monsoon” has an agreed definition and that scientists can explain when it starts and ends. Defining the monsoon is actually quite contentious, leading to the publication of many different definitions. Some define the monsoon onset according to rainfall, wind change, cloud top temperatures, or a combination of these and other factors. Most of these different methods give results that are similar over Bangladesh. They explain that the monsoon starts in the south east part of the country and sweeps northwestward over a couple of weeks around the beginning of June. However, a couple of publications say something quite different. These publications reveal that the monsoon starts considerably –over 1 month- earlier in northeast Bangladesh. These varying results present us with a challenge. If we want to inform the people of Bangladesh about the monsoon onset, how can we decide which definition to use…
Geothermal heating increases the habitability of planets orbiting red dwarfs
Small red stars, known by astronomers as “M-dwarfs”, are the most abundant type of star in the sky and are also the most long-lived of all stars. This means there are plenty nearby of M-dwarfs to search for possible habitable planets, and many current and planned exoplanet surveys emphasize the search for potential worlds orbiting within the habitable zone of these low-mass stars. Astrobiologists often use the term “habitability” to indicate a planet’s ability to sustain liquid water on its surface, thereby providing conditions where life might be able to develop and thrive. The corresponding “habitable zone” describes the range of orbital distances that can support these clement conditions and not lose the water to a rapid runaway greenhouse (from too close an orbit) or a cool condensing atmosphere (from too far an orbit). The problem with planets orbiting M-dwarfs is that they are prone to fall into “synchronous rotation”…
First direct detection and identification of elusive dark matter particles
Cutting-edge paper by Professor George Fraser — who tragically died in March this year — and colleagues at the University of Leicester provides first potential indication of direct detection of Dark Matter — something that has been a mystery in physics for over 30 years. Space scientists at the University of Leicester have detected a curious signal in the X-ray sky — one that provides a tantalising insight into the nature of mysterious Dark Matter. The Leicester team has found what appears to be a signature of ‘axions’, predicted ‘Dark Matter’ particle candidates — something that has been a puzzle to science for years. In a study being published on Monday 20 October in the Monthly Notices of the Royal Astronomical Society, the University of Leicester scientists describe their finding of a signal which has no conventional explanation. As first author Professor George Fraser, who sadly died in March of…
Diving birds at risk due to decline in fish stocks in Puget Sound
Birds that dive for fish while wintering in the Salish Sea, located between British Columbia and Washington, are more likely to be in decline than nondiving birds with less specialized diets, according to a study led by the School of Veterinary Medicine at the University of California, Davis. Diving birds were 11 times more likely to be in decline than nondiving birds, according to the study, published in the journal Conservation Biology. Also, populations of diving birds that rely on forage fish, such as Pacific herring, are 16 times more likely to decline than those with more varied diets. The study lends credence to what scientists have long suspected: “If you want to recover birds, you need to recover the food that they’re eating,” said co-author Joe Gaydos, a UC Davis wildlife veterinarian and director of the SeaDoc Society, a program of the UC Davis Karen C. Drayer Wildlife Health…
Competition between related species of lizards can drive evolution really fast
Scientists working on islands in Florida have documented the rapid evolution of a native lizard species — in as little as 15 years — as a result of pressure from an invading lizard species, introduced from Cuba. After contact with the invasive species, the native lizards began perching higher in trees, and, generation after generation, their feet evolved to become better at gripping the thinner, smoother branches found higher up. The change occurred at an astonishing pace: Within a few months, native lizards had begun shifting to higher perches, and over the course of 15 years and 20 generations, their toe pads had become larger, with more sticky scales on their feet. “We did predict that we’d see a change, but the degree and quickness with which they evolved was surprising,” said Yoel Stuart, a postdoctoral researcher in the Department of Integrative Biology at The University of Texas at Austin…