Archive for May, 2013

The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments

Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive 35S targeting SR in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~40–75°C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~26°C, pH ~8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity.

Continue reading ‘The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments’

Rock magnetic record of the Triassic-Jurassic transition in pelagic bedded chert of the Inuyama section, Japan

The end-Triassic mass extinction event is regarded as one of the five largest extinction events of the Phanerozoic. The emerging consensus points to volcanic activity at the Central Atlantic Magmatic Province (CAMP) as the ultimate cause of the extinction, yet the underlying mechanisms and the nature of global environmental changes that accompanied the biotic turnover remain elusive. We present a rock magnetic study of the extinction interval found within a continuous chert sequence that provides an uninterrupted record of pelagic sedimentation in the Panthalassa Ocean. The variations in the relative abundances and characteristics of authigenic magnetic phases indicate that the Triassic-Jurassic transition progressed in two stages. The initial stage, characterized by a disappearance of the previously ubiquitous magneto­fossils, started a few tens of thousands of years to 100 k.y. prior to the formal Triassic-Jurassic boundary as identified by the diagnostic radiolarian species. The second stage, defined by significant changes in optical and magnetic properties of hematite pigment, lasted a few tens of thousands of years. The stepwise change in magnetic properties is suggestive of the protracted environmental deterioration, likely prompted by the early episodes of the CAMP volcanism, which was followed by a sudden ocean acidification event, perhaps triggered by a catastrophic release of gas hydrates.

Continue reading ‘Rock magnetic record of the Triassic-Jurassic transition in pelagic bedded chert of the Inuyama section, Japan’

Small-scale U.S. lab experiment removes CO2 from atmosphere at relatively low cost

Scientists say they have found a cheaper and more efficient way to capture carbon dioxide from the atmosphere.

The researchers from Lawrence Livermore National Laboratory also say that their tested process has added benefits — it may be able to reduce ocean acidification and, at the same time, produce hydrogen for use as a fuel or an industrial feedstock.

“It is much less energy-intensive and much less costly than some of the other air capture ideas that have been proposed,” said Greg Rau, a visiting scientist at the national lab and lead author of the research, which was published this week in the Proceedings of the National Academy of Sciences.

Continue reading ‘Small-scale U.S. lab experiment removes CO2 from atmosphere at relatively low cost’

Scientists invent super clean hydrogen fuel technique that could save us all

Could researchers possibly have stumbled upon the solution to our acidified oceans?

Question: What happens when you put together salty water, silicate minerals and some electrical current?

Answer: If a new technique pans out, a potential solution to some of our most vexing energy problems.

A new study, published this week in the journal Proceedings of the National Academy of Sciences, outlines a way to produce hydrogen while also capturing carbon dioxide and producing a base that could be used to offset or neutralize ocean acidification. Hydrogen is an ideal fuel source since its only byproduct is water.

Continue reading ‘Scientists invent super clean hydrogen fuel technique that could save us all’

Scientists develop “Alka Seltzer” for the ocean in order to combat growing acidification

Scientists have discovered a new method that may save the world’s marine ecosystems by offsetting ocean acidification.

The researchers, which include a group from Lawrence Livermore National Laboratory (LLNL), has mastered on a laboratory scale a system that uses the acidity normally produced in saline water electrolysis to accelerate silicate mineral dissolution while producing hydrogen fuel and other gases.

Continue reading ‘Scientists develop “Alka Seltzer” for the ocean in order to combat growing acidification’

Scientists develop CO2 sequestration technique that produces ‘supergreen’ hydrogen fuel

Lawrence Livermore scientists have discovered and demonstrated a new technique to remove and store atmospheric carbon dioxide while generating carbon-negative hydrogen and producing alkalinity, which can be used to offset ocean acidification.

The team demonstrated, at a laboratory scale, a system that uses the acidity normally produced in electrolysis to accelerate silicate mineral dissolution while producing and other gases. The resulting was shown to be significantly elevated in hydroxide concentration that in turn proved strongly absorptive and retentive of atmospheric CO2.

Continue reading ‘Scientists develop CO2 sequestration technique that produces ‘supergreen’ hydrogen fuel’

Carbon capture technique produces hydrogen fuel, offsets ocean acidification

LIVERMORE, Calif. — Lawrence Livermore scientists have discovered and demonstrated a new technique to remove and store atmospheric carbon dioxide while generating carbon-negative hydrogen and producing alkalinity, which can be used to offset ocean acidification.

The team demonstrated, at a laboratory scale, a system that uses the acidity normally produced in saline water electrolysis to accelerate silicate mineral dissolution while producing hydrogen fuel and other gases. The resulting electrolyte solution was shown to be significantly elevated in hydroxide concentration that in turn proved strongly absorptive and retentive of atmospheric CO2.

Continue reading ‘Carbon capture technique produces hydrogen fuel, offsets ocean acidification’

Rep. DeFazio points to reports of ocean acidification, oceans at high risk from climate change (video)

WASHINGTON, DC— Today, Congresswoman Peter DeFazio (OR-04), member of the Safe Climate Caucus, spoke on the House floor to address a number of reports on increasing ocean acidification, finding that increased CO2 levels in the water are resulting in threats to many species of fish and the whole ocean food chain.  He highlighted two studies from Oregon State University, finding evidence of rapidly increasing global temperatures and exploring potential future implications of ocean acidification for the shellfish industry.

Continue reading ‘Rep. DeFazio points to reports of ocean acidification, oceans at high risk from climate change (video)’

EPA takes unprecedented step toward new water-quality standards for ocean acidification

SAN FRANCISCO— In response to a petition from the Center for Biological Diversity, the U.S. Environmental Protection Agency is beginning an in-depth study about combating ocean acidification and reducing pollution that’s having a dramatic impact on corals, shellfish and other sea life. The decision marks the first time the EPA has launched a formal workgroup to identify national water quality standards that can be used to detect the effects of ocean acidification marine life. The agency has announced that within the next six months it will convene a panel of scientists and policy makers to discuss the Center’s petition.

“We’re happy to see the EPA taking this first step toward protecting fisheries and coastal ecosystems before it’s too late,” said Miyoko Sakashita, oceans director at the Center. “Our oceans are in the midst of a dangerous transformation that, left unchecked, will make sea waters inhospitable for many, many animals. It’s not too late, though, and this working group will be tasked with deciding where the tipping points are, so we can act now to prevent the worst effects.”

Continue reading ‘EPA takes unprecedented step toward new water-quality standards for ocean acidification’

Zeitmaschine in den Ozean der Zukunft (in German)

Kieler Meeresforscher untersuchen in einem schwedischen Fjord, wie Ozeanbewohner mit einem stark erhöhten CO2-Gehalt zurechtkommen.

Kiel/Kristineberg. Im Grunde hat Ulf Riebesell zwölf Kinder. Zwei leben in Kiel, die anderen zehn in einem schwedischen Fjord nördlich von Göteborg. Zwar tragen sie die eher lieblos anmutenden Namen 1 bis 10 und bestehen aus viel Kunststoff, Metall und Seilen. Doch wenn der Kieler Meeresbiologe über seine Mesokosmen spricht, dann schwingt so viel Begeisterung und Fürsorge mit, dass man meinen könnte, ein Vater spricht voller Stolz über seinen Nachwuchs, dessen Entwicklung er im Detail beobachtet – und den er kaum einen Tag allein lassen mag. “Da hängt mein Herz dran”, sagt er.

Continue reading ‘Zeitmaschine in den Ozean der Zukunft (in German)’


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