Showing posts with label National Science Foundation. Show all posts
Showing posts with label National Science Foundation. Show all posts

Sunday, May 4, 2014

National Science Foundation : Viruses wage war on deep-sea bacteria to essentially feed and propagate

ScienceDaily: Your source for the latest research news

 

Undersea warfare: Viruses hijack deep-sea bacteria at hydrothermal vents

Date:
May 1, 2014
Source:
National Science Foundation
Summary:
More than a mile beneath the ocean's surface, as dark clouds of mineral-rich water billow from seafloor hot springs called hydrothermal vents, unseen armies of viruses and bacteria wage war.
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Credit: NOAA
[Click to enlarge image]

More than a mile beneath the ocean's surface, as dark clouds of mineral-rich water billow from seafloor hot springs called hydrothermal vents, unseen armies of viruses and bacteria wage war.
Like pirates boarding a treasure-laden ship, the viruses infect bacterial cells to get the loot: tiny globules of elemental sulfur stored inside the bacterial cells.
Instead of absconding with their prize, the viruses force the bacteria to burn their valuable sulfur reserves, then use the unleashed energy to replicate.
"Our findings suggest that viruses in the dark oceans indirectly access vast energy sources in the form of elemental sulfur," said University of Michigan marine microbiologist and oceanographer Gregory Dick, whose team collected DNA from deep-sea microbes in seawater samples from hydrothermal vents in the Western Pacific Ocean and the Gulf of California.
"We suspect that these viruses are essentially hijacking bacterial cells and getting them to consume elemental sulfur so the viruses can propagate themselves," said Karthik Anantharaman of the University of Michigan, first author of a paper on the findings published this week in the journal Science Express.
Similar microbial interactions have been observed in shallow ocean waters between photosynthetic bacteria and the viruses that prey upon them.
But this is the first time such a relationship has been seen in a chemosynthetic system, one in which the microbes rely solely on inorganic compounds, rather than sunlight, as their energy source.
"Viruses play a cardinal role in biogeochemical processes in ocean shallows," said David Garrison, a program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research. "They may have similar importance in deep-sea thermal vent environments."

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Wednesday, March 19, 2014

Nasa-funded study: industrial civilisation headed for 'irreversible collapse'?


Friday 14 March 2014 14.28 EDT

Natural and social scientists develop new model of how 'perfect storm' of crises could unravel global system
This NASA Earth Observatory released on
This Nasa Earth Observatory image shows a storm system circling around an area of extreme low pressure in 2010, which many scientists attribute to climate change. Photograph: AFP/Getty Images
A new study sponsored by Nasa's Goddard Space Flight Center has highlighted the prospect that global industrial civilisation could collapse in coming decades due to unsustainable resource exploitation and increasingly unequal wealth distribution.
Noting that warnings of 'collapse' are often seen to be fringe or controversial, the study attempts to make sense of compelling historical data showing that "the process of rise-and-collapse is actually a recurrent cycle found throughout history." Cases of severe civilisational disruption due to "precipitous collapse - often lasting centuries - have been quite common."
The research project is based on a new cross-disciplinary 'Human And Nature DYnamical' (HANDY) model, led by applied mathematician Safa Motesharri of the US National Science Foundation-supported National Socio-Environmental Synthesis Center, in association with a team of natural and social scientists. The study based on the HANDY model has been accepted for publication in the peer-reviewed Elsevier journal, Ecological Economics.
It finds that according to the historical record even advanced, complex civilisations are susceptible to collapse, raising questions about the sustainability of modern civilisation:
"The fall of the Roman Empire, and the equally (if not more) advanced Han, Mauryan, and Gupta Empires, as well as so many advanced Mesopotamian Empires, are all testimony to the fact that advanced, sophisticated, complex, and creative civilizations can be both fragile and impermanent."
By investigating the human-nature dynamics of these past cases of collapse, the project identifies the most salient interrelated factors which explain civilisational decline, and which may help determine the risk of collapse today: namely, Population, Climate, Water, Agriculture, and Energy.
These factors can lead to collapse when they converge to generate two crucial social features: "the stretching of resources due to the strain placed on the ecological carrying capacity"; and "the economic stratification of society into Elites [rich] and Masses (or "Commoners") [poor]" These social phenomena have played "a central role in the character or in the process of the collapse," in all such cases over "the last five thousand years."
Currently, high levels of economic stratification are linked directly to overconsumption of resources, with "Elites" based largely in industrialised countries responsible for both:
"... accumulated surplus is not evenly distributed throughout society, but rather has been controlled by an elite. The mass of the population, while producing the wealth, is only allocated a small portion of it by elites, usually at or just above subsistence levels."
The study challenges those who argue that technology will resolve these challenges by increasing efficiency:
"Technological change can raise the efficiency of resource use, but it also tends to raise both per capita resource consumption and the scale of resource extraction, so that, absent policy effects, the increases in consumption often compensate for the increased efficiency of resource use."
Productivity increases in agriculture and industry over the last two centuries has come from "increased (rather than decreased) resource throughput," despite dramatic efficiency gains over the same period.


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