PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Oxygen-free early oceans likely delayed rise of life on planet

New findings from UC Riverside-led team alter traditional ideas about ancient ocean chemistry

Oxygen-free early oceans likely delayed rise of life on planet
2011-01-11
(Press-News.org) RIVERSIDE, Calif. – Geologists at the University of California, Riverside have found chemical evidence in 2.6-billion-year-old rocks that indicates that Earth's ancient oceans were oxygen-free and, surprisingly, contained abundant hydrogen sulfide in some areas.

"We are the first to show that ample hydrogen sulfide in the ocean was possible this early in Earth's history," said Timothy Lyons, a professor of biogeochemistry and the senior investigator in the study, which appears in the February issue of Geology. "This surprising finding adds to growing evidence showing that ancient ocean chemistry was far more complex than previously imagined and likely influenced life's evolution on Earth in unexpected ways – such as, by delaying the appearance and proliferation of some key groups of organisms."

Ordinarily, hydrogen sulfide in the ocean is tied to the presence of oxygen in the atmosphere. Even small amounts of oxygen favor continental weathering of rocks, resulting in sulfate, which in turn gets transported to the ocean by rivers. Bacteria then convert this sulfate into hydrogen sulfide.

How then did the ancient oceans contain hydrogen sulfide in the near absence of oxygen, as the 2.6-million-year-old rocks indicate? The UC Riverside-led team explains that sulfate delivery in an oxygen-free environment can also occur in sufficient amounts via volcanic sources, with bacteria processing the sulfate into hydrogen sulfide.

Specifically, Lyons and colleagues examined rocks rich in pyrite – an iron sulfide mineral commonly known as fool's gold – that date back to the Archean eon of geologic history (3.9 to 2.5 billion years ago) and typify very low-oxygen environments. Found in Western Australia, these rocks have preserved chemical signatures that constitute some of the best records of the very early evolutionary history of life on the planet.

The rocks formed 200 million years before oxygen amounts spiked during the so-called "Great Oxidation Event" – an event 2.4 billion years ago that helped set the stage for life's proliferation on Earth.

"Our previous work showed evidence for hydrogen sulfide in the ocean more than 100 million years before the first appreciable accumulation of oxygen in the atmosphere at the Great Oxidation Event," Lyons said. "The data pointing to this 2.5 billion-year-old hydrogen sulfide are fingerprints of incipient atmospheric oxygenation. Now, in contrast, our evidence for abundant 2.6 billion-year-old hydrogen sulfide in the ocean – that is, another 100 million years earlier – shows that oxygen wasn't a prerequisite. The important implication is that hydrogen sulfide was potentially common for a billion or more years before the Great Oxidation Event, and that kind of ocean chemistry has key implications for the evolution of early life."

Clint Scott, the first author of the research paper and a former graduate student in Lyons's lab, said the team was also surprised to find that the Archean rocks recorded no enrichments of the trace element molybdenum, a key micronutrient for life that serves as a proxy for oceanic and atmospheric oxygen amounts.

The absence of molybdenum, Scott explained, indicates the absence of oxidative weathering of the continental rocks at this time (continents are the primary source of molybdenum in the oceans). Moreover, the development of early life, such as cyanobacteria, is determined by the amount of molybdenum in the ocean; without this life-affirming micronutrient, cyanobacteria could not become abundant enough to produce large quantities of oxygen.

"Molybdenum is enriched in our previously studied 2.5 billion-year-old Archean rocks, which ties to the earliest hints of atmospheric oxygenation as a harbinger of the Great Oxidation Event," Scott said. "The scarcity of molybdenum in rocks deposited 100 million years earlier, however, reflects its scarcity also in the overlying water column. Such metal deficiencies suggest that cyanobacteria were probably struggling to produce oxygen when these rocks formed.

"Our research has important implications for the evolutionary history of life on Earth," Scott added, "because biological evolution both initiated and responded to changes in ocean chemistry. We are trying to piece together the cause-and-effect relationships that resulted, billions of years later, in the evolution of animals and, ultimately, humans. This is really the story of how we got here."

The first animals do not appear in the fossil record until around 600 million years ago – almost two billion years after the rocks studied by Scott and his team formed. The steady build-up of oxygen, which began towards the end of the Archean, played a key role in the evolution of new life forms.

"Future research needs to focus on whether sulfidic and oxygen-free conditions were prevalent throughout the Archean, as our model predicts," Scott said.



INFORMATION:

Lyons and Scott were accompanied on this project by Christopher Reinhard from UCR; Andrey Bekker from the University of Manitoba, Canada; Bernhard Schnetger from Oldenburg University, Germany; Bryan Krapež from the Curtin University of Technology, Western Australia; and Douglas Rumble III from the Carnegie Institution of Washington, Washington, DC. Currently, Scott is a postdoctoral researcher at McGill University, Canada.

Funding for this work came from the National Science Foundation, the NASA Exobiology Program, the NASA Astrobiology Institute, and through a Canadian National Sciences and Engineering Research Council Discovery Grant.

The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 20,500 students. The campus will open a medical school in 2012 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Graduate Center. The campus has an annual statewide economic impact of more than $1 billion.

A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. To learn more, call (951) UCR-NEWS.


[Attachments] See images for this press release:
Oxygen-free early oceans likely delayed rise of life on planet

ELSE PRESS RELEASES FROM THIS DATE:

Does it hurt?

2011-01-11
It is well known that pain is a highly subjective experience. We each have a pain threshold, but this can vary depending on distractions and mood. A paper in the International Journal of Behavioural and Healthcare Research offers a cautionary note on measuring perceived pain in research. There are many chronic illnesses and injuries that have no well-defined symptoms other than pain, but because of the subjectivity in a patient's reporting of their experience of the illness or injury, healthcare workers have difficulty in addressing the patient's needs. Moreover, when ...

New method takes snapshots of proteins as they fold

New method takes snapshots of proteins as they fold
2011-01-11
People have only 20,000 to 30,000 genes (the number is hotly contested), but they use those genes to make more than 2 million proteins. It's the protein molecules that domost of the work in the human cell. After all, the word protein comes from the Greek prota, meaning "of primary importance." Proteins are created as chains of amino acids, and these chains of usually fold spontaneously into what is called their "native form" in milliseconds or a few seconds. A protein's function depends sensitively on its shape. For example, enzymes and the molecules they alter are ...

Universities miss chance to identify depressed students

2011-01-11
CHICAGO --- One out of every four or five students who visits a university health center for a routine cold or sore throat turns out to be depressed, but most centers miss the opportunity to identify these students because they don't screen for depression, according to new Northwestern Medicine research. About 2 to 3 percent of these depressed students have had suicidal thoughts or are considering suicide, the study found. "Depression screening is easy to do, we know it works, and it can save lives," said Michael Fleming, professor of family and community medicine ...

'Hot-bunking' bacterium recycles iron to boost ocean metabolism

2011-01-11
In the vast ocean where an essential nutrient—iron—is scarce, a marine bacterium that launches the ocean food web survives by using a remarkable biochemical trick: It recycles iron. By day, it uses iron in enzymes for photosynthesis to make carbohydrates; then by night, it appears to reuse the same iron in different enzymes to produce organic nitrogen for proteins. The bacterium, Crocosphaera watsonii, is one of the few marine microbes that can convert nitrogen gas into organic nitrogen, which (just as it does on land) acts as fertilizer to stimulate plant growth in ...

Men with macho faces attractive to fertile women, researchers find

2011-01-11
When their romantic partners are not quintessentially masculine, women in their fertile phase are more likely to fantasize about masculine-looking men than are women paired with George Clooney types. But women with masculine-looking partners do not necessarily become more attracted to their partners, a recent study co-authored by a University of Colorado at Boulder researcher concludes. Meanwhile, a man's intelligence has no effect on the extent to which fertile, female partners fantasize about others, the researchers found. They say the lack of an observed "fertility ...

GEN reports on biotech acquisition deals in 2010 that topped $1 billion

2011-01-11
New Rochelle, NY, January 10, 2011—The mega-mergers of 2009 did not continue into 2010. While the three biggest acquisitions in 2009 each had a price tag of more than $40 billion, only last year's top purchase got above that mark, according to an evaluation of reported deals conducted by Genetic Engineering & Biotechnology News (GEN) (http://www.genengnews.com/). The only other mega takeover for the year, sanofi-aventis' move to buy Genzyme, is still being worked out. A look at 2010's buyouts that crossed the $1billion mark (http://www.genengnews.com/gen-news-highlights/acquisition-deals-in-2010-that-topped-1b/81244443/) ...

Abstinence, heavy drinking, binge drinking associated with increased risk of cognitive impairment

2011-01-11
Amsterdam, The Netherlands, January 10, 2011 -- Previous research regarding the association between alcohol consumption and dementia or cognitive impairment in later life suggests that mild to moderate alcohol consumption might be protective of dementia. However, most of the research has been conducted on subjects already rather elderly at the start of the follow-up. A new study published in the December issue of the Journal of Alzheimer's Disease addresses this problem with a follow-up of more than two decades. The study, conducted at the University of Turku, University ...

Nuclear receptors reveal possible interventions for cancer, obesity

Nuclear receptors reveal possible interventions for cancer, obesity
2011-01-11
HOUSTON, Jan. 10, 2011 – Research with significant implications in the treatment and intervention of cancer and obesity has been published recently in two prestigious journals by University of Houston (UH) biochemist Dr. Jan-Åke Gustafsson. In an invited review in the Journal of Biological Chemistry, the most-cited biomedical research journal in the world, Gustafsson and his team summarize the most recent results pertaining to the function of a nuclear receptor called estrogen receptor beta, or ERbeta, the biological and medical importance of which Gustafsson and his ...

CT helps identify bullet trajectories

2011-01-11
OAK BROOK, Ill. – Multidetector computed tomography (MDCT) provides an efficient, effective way to analyze wounds from bullets and explosive devices, according to a study published online and in the March issue of Radiology. "The information provided by MDCT has the potential to improve patient care and aid in both military and civilian forensic investigations," said the study's lead author, Les R. Folio, D.O., M.P.H., from the Uniformed Services University in Bethesda, Md. U.S. troops stationed in Iraq and Afghanistan face threats from increased sniper activity and ...

Shellfish safer to eat thanks to breakthrough by Queen's scientists

2011-01-11
New technology to make shellfish safer to eat has been pioneered by scientists at Queen's University Belfast. The new test, developed at Queen's Institute for Agri-Food and Land Use, not only ensures shellfish are free of toxins before they reach the food chain but is likely to revolutionise the global fishing industry. While the current process for monitoring potentially dangerous toxins in shellfish takes up to two days, the new test slashes the testing time to just 30 minutes using new biosensor technology and provides a much more reliable result. The test detects ...

LAST 30 PRESS RELEASES:

Evolution of fast-growing fish-eating herring in the Baltic Sea

Cryptographic protocol enables secure data sharing in the floating wind energy sector

Can drinking coffee or tea help prevent head and neck cancer?

Development of a global innovative drug in eye drop form for treating dry age-related macular degeneration

Scientists unlock secrets behind flowering of the king of fruits

Texas A&M researchers illuminate the mysteries of icy ocean worlds

Prosthetic material could help reduce infections from intravenous catheters

Can the heart heal itself? New study says it can

Microscopic discovery in cancer cells could have a big impact

Rice researchers take ‘significant leap forward’ with quantum simulation of molecular electron transfer

Breakthrough new material brings affordable, sustainable future within grasp

How everyday activities inside your home can generate energy

Inequality weakens local governance and public satisfaction, study finds

Uncovering key molecular factors behind malaria’s deadliest strain

UC Davis researchers help decode the cause of aggressive breast cancer in women of color

Researchers discovered replication hubs for human norovirus

SNU researchers develop the world’s most sensitive flexible strain sensor

Tiny, wireless antennas use light to monitor cellular communication

Neutrality has played a pivotal, but under-examined, role in international relations, new research shows

Study reveals right whales live 130 years — or more

Researchers reveal how human eyelashes promote water drainage

Pollinators most vulnerable to rising global temperatures are flies, study shows

DFG to fund eight new research units

Modern AI systems have achieved Turing's vision, but not exactly how he hoped

Quantum walk computing unlocks new potential in quantum science and technology

Construction materials and household items are a part of a long-term carbon sink called the “technosphere”

First demonstration of quantum teleportation over busy Internet cables

Disparities and gaps in breast cancer screening for women ages 40 to 49

US tobacco 21 policies and potential mortality reductions by state

AI-driven approach reveals hidden hazards of chemical mixtures in rivers

[Press-News.org] Oxygen-free early oceans likely delayed rise of life on planet
New findings from UC Riverside-led team alter traditional ideas about ancient ocean chemistry