Impact of Deepwater Horizon Oil Spill on Coral Communities Is Deeper and Broader than Predicted

Credit: Fisher lab, Penn State UniversityA new discovery of two additional coral communities showing signs of damage from the Deepwater Horizon oil spill expands the impact footprint of the 2010 spill in the Gulf of Mexico. The discovery was made by a team led by Charles Fisher, professor of biology at Penn State University. A paper describing this work and additional impacts of human activity on corals in the Gulf of Mexico will be published during the last week of July 2014 in the online Early Edition of the journal Proceedings of the National Academy of Sciences.

"The footprint of the impact of the spill on coral communities is both deeper and wider than previous data indicated," said Fisher. "This study very clearly shows that multiple coral communities, up to 22 kilometres from the spill site and at depths over 1800 meters, were impacted by the spill."

Sea ice decline driving changes in arctic air pollutants

Drastic reductions in Arctic sea ice in the last decade may be intensifying the chemical release of bromine into the atmosphere, resulting in ground-level ozone depletion and the deposit of toxic mercury in the Arctic, according to a new NASA-led study.

The connection between changes in the Arctic Ocean's ice cover and bromine chemical processes is determined by the interaction between the salt in sea ice, frigid temperatures and sunlight. When these mix, the salty ice releases bromine into the air and starts a cascade of chemical reactions called a "bromine explosion." These reactions rapidly create more molecules of bromine monoxide in the atmosphere. Bromine then reacts with a gaseous form of mercury, turning it into a pollutant that falls to Earth's surface.

Current rates of ocean acidification are unparalleled in Earth's history

The study, based on an expert workshop led by Columbia University's Lamont-Doherty Earth Observatory and the University of Bristol, assessed in detail a number of climate change events in the planet's history, including the asteroid impact that made the dinosaurs go extinct and the Permian mass-extinction which wiped out around 95 per cent of all life on Earth. The findings are reported this week in Science.

Oceans are currently absorbing about a quarter of the CO2 released into the atmosphere, lowering the pH of the surface ocean. As atmospheric CO2 increases, so does the rate at which it will dissolve in seawater, forcing surface ocean pH lower and lower – a process called ocean acidification.

CO2-chomping microbes battling for ocean iron

Australian, Belgian and New Zealand scientists have expanded our understanding of the way phyoplankton take up scarce iron in the ocean – a process that regulates ocean food chains from the bottom up and helps remove up to 40 per cent of carbon dioxide (CO2) from the atmosphere.

Research published recently in the Proceedings of the National Academy of Science explores the relationship between iron, which limits primary productivity in vast regions of the ocean, and its uptake by phytoplankton species.

Dolphins' health shed light on human and ocean health

The Georgia Dolphin Health Assessment capture-release study provides information on the health of the wild dolphin population that inhabits estuaries along the Georgia coast.
Credit: Brian Balmer, Sarasota Dolphin Research ProgramnScientists discover clues into human diseases by studying dolphins in a changing ocean

A panel of governmental, academic and non-profit scientists speaking today at the annual meeting of the American Association for the Advancement of Science (AAAS) unveiled research suggesting that diseases found in dolphins are similar to human diseases and can provide clues into how human health might be affected by exposure to contaminated coastal water or seafood.

"Dolphins and humans are both mammals, and their diet includes much of the same seafood that we consume. Unlike us, however, they are exposed to potential ocean health threats such as toxic algae or poor water quality 24 hours a day," said Carolyn Sotka of the NOAA Oceans and Human Health Initiative and lead organizer of the session. "Our ecological and physiological similarities make dolphins an important 'sentinel species' to not only warn us of health risks, but also provide insight into how our health can benefit from new medical discoveries."

Measuring carbon dioxide over the ocean

Reliable measurements of the air-sea flux of carbon dioxide – an important greenhouse gas – are needed for a better understanding of the impact of ocean-atmosphere interactions on climate. A new method developed by researchers at the National Oceanography Centre, Southampton (NOCS) working in collaboration with colleagues at the Bjerknes Center for Climate Research (Bergen, Norway) promises to make this task considerably easier.

Infrared gas sensors measure carbon dioxide based on its characteristic absorption spectra and are used to evaluate the air-sea flux of the gas. So-called closed-path sensors precondition air before measurements are made, while open-path sensors can be used to measure the air in situ.

Oceans absorbing carbon dioxide more slowly

Photo:Yale UniversityThe world’s oceans are absorbing less carbon dioxide (CO₂), a Yale geophysicist has found after pooling data taken over the past 50 years. With the oceans currently absorbing over 40 per cent of the CO₂ emitted by human activity, this could quicken the pace of climate change, according to the study, which appears in the November 25 issue of Geophysical Research Letters.

Jeffrey Park, professor of geology and geophysics and director of the Yale Institute for Biospheric Studies, used data collected from atmospheric observing stations in Hawaii, Alaska and Antarctica to study the relationship between fluctuations in global temperatures and the global abundance of atmospheric CO₂ on interannual (one to 10 years) time scales.

Oceanic crust formation is dynamic after all

Imagine the Earth's crust as the planet's skin: Some areas are old and wrinkled while others have a fresher, more youthful sheen, as if they had been regularly lathered with lotion.

Carry the metaphor a little further and a good picture emerges of the geological processes leading to the creation of the planet's crust. On land, continental crust, once created, can remain more or less unaltered for billions of years. But the oldest oceanic crust is only about 200 million years old, as new crust is continually forming at mid-ocean ridge spreading centres.

Extinction rates higher in open oceans during mass extinctions

Arnie Miller. Photo: Dottie StoverEnvironmental selectivity during three of the 'Big Five' mass extinction events focus of two paleontologists' latest research.

Arnie Miller, University of Cincinnati professor of paleontology in the McMicken College of Arts & Sciences, and co-author Michael Foote of the University of Chicago publish their research in the Nov. 20 issue of Science with their paper, "Epicontinental Seas Versus Open-Ocean Settings: The Kinetics of Mass Extinction and Origination."

Optical properties of the Antarctic system and new radiation information

The system has an important part in the global climate due to its size, its high latitude location and the negative radiation balance of its large ice sheets. Antarctica has also been in focus for several decades due to increased ultraviolet (UV) levels caused by stratospheric ozone depletion, and the disintegration of its ice shelves.

During the summer of 1997-1998, measurements of beam absorption and beam attenuation coefficients, and downwelling and upwelling irradiance were made in the Southern Ocean along a S-N transect at 6 degrees E.

Earth's early ocean cooled more than a billion years earlier than thought

The scalding-hot sea that supposedly covered the early Earth may in fact never have existed, according to a new study by Stanford University researchers who analyzed isotope ratios in 3.4 billion-year-old ocean floor rocks. Their findings suggest that the early ocean was much more temperate and that, as a result, life likely diversified and spread across the globe much sooner in Earth's history than has been generally theorised.

It also means that the chemical composition of the ancient ocean was significantly different from today's ocean, which in turn may change interpretations of how the early atmosphere evolved, said Page Chamberlain, professor of environmental earth system science.

When rocks form on the ocean floor, they form in chemical equilibrium with the ocean water, incorporating similar proportions of different isotopes into the rock as are in the water. Isotopes are atoms of the same element that have different numbers of neutrons in the nucleus, giving them different masses. However, because the exact proportion of different isotopes that go into the rock is partly temperature dependent, the ratios in the rock provide critical clues into how warm the ocean was when the rock formed.

Previous studies of similarly aged rocks had looked only at oxygen isotope ratios, which suggested that in the Archean era (about 3.5 billion years ago), the ocean temperature was at least 55 degrees Celsius and may have been as high as 85 C, or 185 F. At a water temperature so perilously close to the boiling point, the only organisms that could have thrived would have been extremophiles – life forms adapted to extreme environments – such as the microbes that live in the intense heat of deep-sea hydrothermal vents or in hot springs such as at Yellowstone National Park.

But isotope ratios recorded in rocks on the ocean floor are also dependent on the chemical composition of the seawater in which those rocks formed, and the past studies assumed the composition of the ancient ocean was essentially what it is today, which the Stanford study did not.

Using a relatively new approach, Michael Hren and Mike Tice, both Stanford graduate students at the time, analyzed hydrogen isotopes as well as oxygen isotopes in chert, a type of fine-grained sedimentary rock consisting primarily of quartz. The chert they studied was from an ancient deposit, formerly underwater but now on dry land in South Africa.

From a cauldron to a nice warm bath

"By looking at both oxygen and hydrogen in these ancient rocks we were able to put some constraints on how different the ancient ocean composition may have been from today, and then use that composition to try to determine how hot the ancient ocean was," said Hren, who is the lead author of a paper describing the work being published online Nov. 12 by Nature. Tice and Chamberlain are coauthors.

Having data from isotope ratios of two elements allowed the researchers to calculate upper and lower bounds for the range of temperature and composition that could have given rise to the observed ratios. They determined that the ocean temperature could not have been more than 40 C (104 F) – the temperature of a hot tub – and may have been lower in some parts.

"This means that by 3.4 billion years ago, there were at least some places on the surface of the Earth where organisms that could not survive in these hot hydrothermal conditions could exist and thrive," Hren said. "It also suggests that the chemical composition of the ancient ocean was probably not identical to today, as previous studies assumed. It may have been quite different."

The researchers found that the ratio of the two stable isotopes of hydrogen in the chert was tilted away from the heavier of the isotopes – called deuterium.

"The ancient ocean had a lot more hydrogen in it, relative to deuterium, than modern oceans," Chamberlain said.

If the composition of the Archean ocean was significantly different from today, then the atmosphere must have been markedly different, too, owing to the ease with which gases move across the air-water boundary as the ocean and lower atmosphere strive to stay in a rough equilibrium.

That means that sometime during the past 3.4 billion years, the ocean had to lose a lot of hydrogen to the atmosphere to bring the hydrogen isotope ratio in seawater to where it is today. And since oxygen, not hydrogen, has built up in Earth's atmosphere over that same period of time, the atmosphere must have discharged a lot of hydrogen to the only other place it could go: space.

Hren said that some recent models of the early Earth atmosphere suggest that there may have been a prolonged period of hydrogen escaping to space, which would be consistent with the Stanford team's findings.

Little land on the early Earth

The chemical composition of air and water weren't the only things different about Earth during the Archean era.

"We are talking about a time when, if you were looking at the Earth from space, you would hardly see any land mass at all," Tice said. "It would have almost been an ocean world."

The chert samples came from a formation called the Buck Reef Chert, which covered a broad area from shallow to deep marine environments. Some of the chert was probably deposited on the slopes of a volcanic island, similar to those in the Hawaiian Islands, that had gone extinct, cooled, eroded and slowly subsided under the sea, he said.

Tice collected the chert samples from South Africa several years ago while he was a graduate student with Don Lowe, professor of geological and environmental sciences. In 2004, Lowe and Tice described a fossil microbial ecosystem preserved in some of the chert that was deposited on a shallow submerged platform, which they deduced was photosynthetic. Tice said the temperature setting was probably somewhat comparable to a modern day tidal flat, where similar photosynthetic microbial mats flourish today, although the depth of the Archean setting was similar to continental shelves of today.

"At the higher temperatures that were hypothesised earlier, those organisms could have survived but they would have had a harder time," he said. "At the temperatures we are suggesting, they would have been completely comfortable. They would have been happy.

"And that is significant because photosynthetic organisms, even bacteria, form the base of essentially every modern food chain," Tice added.

Checking the chert

With major ramifications for the ocean, atmosphere and nature of life on the early Earth coming out of their study, the researchers know their work is likely to receive some scrutiny.

"Anytime you are dealing with something that has been on Earth for 3.4 billion years, it is always going to be a question of whether these are pristine or not," Chamberlain said.

But the cherts the Stanford team worked with "are particularly good rocks," he said, "because they have not been stuck deep in the Earth, crushed and heated, and so they preserve something of what the original oceans were like."

Still, to rule out any alteration of the rocks, Hren said they did calculations to see what would happen if the chert had been subjected to later hydrothermal water flowing through it, or other post-depositional processes that could potentially alter the chemistry of the samples.

"We can show some of the data has been altered by later fluids, but some of it is recording this original ocean composition and temperature data," he said. "So by looking at these two separate trends, we can see which data reflects this original formation.

"I think it is really giving us a better idea of these conditions at a very early time in the Earth's history," Hren said.

Hren is now a postdoctoral researcher in the Department of Geological Sciences at the University of Michigan at Ann Arbor. Tice is now a professor of geology and geophysics at Texas A&M University in College Station, Texas.

Author: Louis Bergeron

A glimpse at the Earth's crust deep below the Atlantic

TOBI sidescan sonar imagery draped over multibeam bathymetry provides a unique 3-D view of an active oceanic core complex at 13^°19'N, the Mid-Atlantic Ridge. The core complex is the smooth, striated dome forming the left-hand side of the image. To its right is the hummocky neovolcanic zone where recent volcanoes erupt lavas forming the the new oceanic crust. The field of view is around 30km wide. Image: NOCSLong-term variations in volcanism help explain the birth, evolution and death of striking geological features called oceanic core complexes on the ocean floor, says geologist Dr Bram Murton of the National Oceanography Centre, Southampton.

Oceanic core complexes are associated with faults along slow-spreading mid-ocean ridges. They are large elevated massifs with flat or gently curved upper surfaces and prominent corrugations called 'megamullions.' Uplifting during their formation causes exposure of lower crust and mantle rocks on the seafloor.

How much water does the ocean have?

Geodesy researchers observe the mass distribution of the oceans

The calculation of variations in the sea level is relatively simple. It is by far more complicated to then determine the change in the water mass. A team of geodesists and oceanographers from the University of Bonn, as well as from the GFZ German Research Centre for Geosciences and the Alfred-Wegener Institute for Polar and Marine Sciences, two centres of the Helmholtz Association, have now, for the first time succeeded in doing this. The researchers were able to observe short-term fluctuations in the spatial distribution of the ocean water masses. Their results are, amongst others, important for improved climate models.

Don’t shun the ocean – IUCN tells climate leaders

Failure to recognise the ocean in climate change discussions will have profound consequences for humanity, according to IUCN.

A month before world leaders meet in Copenhagen to strike a climate deal, IUCN releases The Ocean and Climate Change – Tools and Guidelines for Action, to help decision-makers understand the importance of the ocean in the global climate debate – and the cost of not taking action. The report provides a comprehensive view of the mitigation and adaptation strategies available, as well as a clear set of action recommendations.

"Maintaining biodiversity and restoring degraded ecosystems are cost-effective strategies for disaster risk reduction and will help poor communities adapt to climate change while ensuring the continued provision of vital services," says Dorothée Herr, lead author of the report and IUCN’s Global Marine Program Officer.

The ocean is the earth’s most significant global heat buffer, and absorbs up to one third of the CO₂ released by human activities. The ocean covers over seventy per cent of our planet’s surface yet much less than one per cent of the ocean is effectively protected. Marine ecosystems such as salt marshes, coral reefs and mangroves are among the most vulnerable to climate change, with millions of people relying on them for food, protection, tourism and development.

The report urges global leaders to significantly reduce CO₂ emissions and to set reduction targets based on the latest science on ocean acidification and marine ecosystems. The report welcomes the development of sustainable marine renewable energy sources and promotes the use of coastal ecosystems as natural carbon sinks. The report however also carries an important warning to world leaders:

"We should explore all possible ways to reduce greenhouse gas emissions," says Carl Gustaf Lundin, Head of IUCN Global Marine Programme. "But proposed actions such as ocean fertilisation to increase carbon capture and storage need to be approached with caution as the possible impacts on the atmosphere and marine biodiversity may be severe and have not been fully evaluated."

Fears over US toxic ship anchored in Indian coast

Platinum II Photo: BANThe worst fears of environmentalists and human rights activists have been confirmed as it is found that an aging American ocean liner, the SS Oceanic (formerly SS Independence), containing significant quantities of asbestos and toxic PCB chemicals, has now arrived at the infamous Alang Port in Gujarat, with a new name – Platinum II.

The ship will be scrapped in contravention of US and international law unless government action on the part of US or Indian authorities is taken as a matter of urgency.

The Oceanic made headlines in 2008 when its former owners, Global Shipping LLC (GSL) and Global Marketing Systems Inc. (GMS) (both of Maryland and part of the Anil Sharma family’s shipbreaking, cashbuying and brokerage interests), were charged by the US government with illegal export of PCBs for disposal and use in commerce under the Toxics Substances Control Act (TSCA).

The EPA acted after the Seatle-based NGO Basel Action Network (BAN) warned that the ship was likely to be carrying PCBs and was known to be headed for the scrapping beaches of South Asia. To avoid a court case to contest this charge, the former owners paid over one half million dollars as a settlement. After EPA pressed charges, the owners denied that the ship was going to be sent for breaking on the beaches of South Asia as the EPA and environmental groups feared and instead claimed it was to be reused as a ship by its new owners.

“US law exists to protect other countries from the scourge of toxic PCBs, and yet we continually fail to diligently enforce these laws,” said Jim Puckett, executive director of BAN, a member organisation of the global NGO Platform on Shipbreaking.

“It is clear now that the government made a terrible mistake in letting this ship sail away. It is now incumbent on the administration to do everything in its power to require India to repatriate the ship for proper toxic waste management as the law requires.”

Meanwhile, BAN has learned that the Maritime Administration (MARAD) aided and abetted the escape of the ship to a foreign jurisdiction by approving the sale of the vessel to a foreign buyer while the EPA was taking legal action against the owners. MARAD sent a letter to GSL in June 2008 offering support for the foreign transfer of the ship to Platinum Investment Services Corp. based in Monrovia, Liberia. Platinum Investment Services appears to be a “mailbox company”: under Liberian law, a company may register without publicly revealing an address, any principle owners, board members or spokespersons of any kind. The company has no office, no website and has no known history of ship operations. It is likely that MARAD’s authorisation of the sale of the ship hampered the EPA’s own legal efforts to demand the ship be returned for proper testing and remediation.

In India, the ship’s arrival violates the Basel Convention to which India is a Party. Under that United Nations Environment Programme (UNEP) treaty, India is not allowed to receive hazardous waste from the US. Nor can it receive hazardous waste from any foreign source without prior notification of arrival and consent from the Indian government. No such notification or consent was provided in advance of the sudden arrival of the toxic ship. Further, the ship's arrival violated the Supreme Court of India’s order of 14th October 2003 and 6th September 2007, which calls for the pre-cleaning of ships of all toxic substances prior to importation.

The incident is reminiscent of the infamous export of the French Aircraft Carrier Le Clemenceau, which in 2006 was exported to India for breaking from France. French courts finally realised the export was a violation of the Basel Convention and demanded the return of the ship.

“The Oceanic's arrival off the Gujarat beaches makes India an international crime scene, with the Maritime Administration abetting such crimes,” said Puckett. “The last time something like this happened, the authorities of the exporting country called the ship back and took responsibility. We are calling on the authorities of India and the US to do nothing less.”

The Platinum II now rests at anchorage off Gopnath point approximately 40 nautical miles from the Alang coast while Indian state authorities decide her fate. GMS denies any ownership of the vessel or of the mystery firm Platinum Investment Services Corp. However, the vessel is slated for breaking at the Leela Ship Recycling plot in Alang, which is owned by Komal Sharma, brother to Anil Sharma, owner of GMS.

African desert rift confirmed as new ocean in the making

Image: ChelysGeologists show that seafloor dynamics are at work in splitting African continent

In 2005, a gigantic, 35-mile-long rift broke open the desert ground in Ethiopia. At the time, some geologists believed the rift was the beginning of a new ocean as two parts of the African continent pulled apart, but the claim was controversial. Now, scientists from several countries have confirmed that the volcanic processes at work beneath the Ethiopian rift are nearly identical to those at the bottom of the world's oceans, and the rift is indeed likely the beginning of a new sea.

The new study, published in the latest issue of Geophysical Research Letters, suggests that the highly active volcanic boundaries along the edges of tectonic ocean plates may suddenly break apart in large sections, instead of little by little as has been predominantly believed. In addition, such sudden large-scale events on land pose a much more serious hazard to populations living near the rift than would several smaller events, says Cindy Ebinger, professor of earth and environmental sciences at the University of Rochester and co-author of the study.

"This work is a breakthrough in our understanding of continental rifting leading to the creation of new ocean basins," says Ken Macdonald, professor emeritus in the Department of Earth Science at the University of California, Santa Barbara, and who is not affiliated with the research. "For the first time they demonstrate that activity on one rift segment can trigger a major episode of magma injection and associated deformation on a neighbouring segment. Careful study of the 2005 mega-dike intrusion and its aftermath will continue to provide extraordinary opportunities for learning about continental rifts and mid-ocean ridges."

"The whole point of this study is to learn whether what is happening in Ethiopia is like what is happening at the bottom of the ocean where it's almost impossible for us to go," says Ebinger. "We knew that if we could establish that, then Ethiopia would essentially be a unique and superb ocean-ridge laboratory for us. Because of the unprecedented cross-border collaboration behind this research, we now know that the answer is yes, it is analogous."

Atalay Ayele, professor at the Addis Ababa University in Ethiopia, led the investigation, painstakingly gathering seismic data surrounding the 2005 event that led to the giant rift opening more than 20 feet in width in just days. Along with the seismic information from Ethiopia, Ayele combined data from neighbouring Eritrea with the help of Ghebrebrhan Ogubazghi, professor at the Eritrea Institute of Technology, and from Yemen with the help of Jamal Sholan of the National Yemen Seismological Observatory Centre. The map he drew of when and where earthquakes happened in the region fit tremendously well with the more detailed analyses Ebinger has conducted in more recent years.

Ayele's reconstruction of events showed that the rift did not open in a series of small earthquakes over an extended period of time, but tore open along its entire 35-mile length in just days. A volcano called Dabbahu at the northern end of the rift erupted first, then magma pushed up through the middle of the rift area and began "unzipping" the rift in both directions, says Ebinger.

Since the 2005 event, Ebinger and her colleagues have installed seismometers and measured 12 similar – though dramatically less intense – events.

"We know that seafloor ridges are created by a similar intrusion of magma into a rift, but we never knew that a huge length of the ridge could break open at once like this," says Ebinger. She explains that since the areas where the seafloor is spreading are almost always situated under miles of ocean, it's nearly impossible to monitor more than a small section of the ridge at once so there's no way for geologists to know how much of the ridge may break open and spread at any one time. "Seafloor ridges are made up of sections, each of which can be hundreds of miles long. Because of this study, we now know that each one of those segments can tear open in a just a few days."

Ebinger and her colleagues are continuing to monitor the area in Ethiopia to learn more about how the magma system beneath the rift evolves as the rift continues to grow.

Additional authors of the study include Derek Keir, Tim Wright, and Graham Stuart, professors of earth and environment at the University of Leeds, U.K.; Roger Buck, professor at the Earth Institute at Columbia University, N.Y.; and Eric Jacques, professor at the Institute de Physique du Globe de Paris, France.

Ancient ocean oxygen production began 100 million years earlier than thought

Scientists studied 2.5 billion-year-old sediments from under Australia's red-weathered hills. Photo: Ariel Anbar/ASUEven low concentrations of oxygen can have profound effects on ocean chemistry

Scientists widely accept that around 2.4 billion years ago, the Earth's atmosphere underwent a dramatic change when oxygen levels rose sharply.

Called the "Great Oxidation Event" (GOE), the oxygen spike marks an important milestone in Earth's history, the transformation from an oxygen-poor atmosphere to an oxygen-rich one, paving the way for complex life to develop.

Two questions that remain unresolved in studies of the early Earth are when oxygen production via photosynthesis got started, and when it began to alter the chemistry of Earth's ocean and atmosphere.

Now a research team led by geoscientists at the University of California at Riverside (UCR) corroborates recent evidence that oxygen production began in Earth's oceans at least 100 million years before the GOE.

"Their findings go a step farther," says Enriqueta Barrera, program director in the National Science Foundation (NSF)'s division of earth sciences, which funded the research along with NASA, "to demonstrating that even very low concentrations of oxygen can have profound effects on ocean chemistry."

Study results appear in this week's issue of the journal Science.

To arrive at their results, the researchers analysed 2.5 billion-year-old black shales from Western Australia. Fossilised pieces of the ancient seafloor, the fine layers within the rocks allowed the researchers to page through ocean chemistry's evolving history.

The shales revealed that episodes of hydrogen sulfide accumulation in the oxygen-free deep ocean occurred nearly 100 million years before the GOE, and up to 700 million years earlier than such conditions were predicted by past models.

Scientists have long believed that the early ocean, for more than half of Earth's 4.6 billion-year history, was characterised by high amounts of dissolved iron under conditions of essentially no oxygen.

"The conventional wisdom has been that appreciable atmospheric oxygen is needed for sulfidic conditions to develop in the ocean," said Chris Reinhard, an earth scientist at UCR and one of the research team members.

"We found, however, that sulfidic conditions in the ocean are possible even when there is very little oxygen, below about 1/100,000th of that in the modern atmosphere."

Even very low oxygen levels in the atmosphere, the mineral pyrite can weather on the continents, resulting in the delivery of sulfate to the ocean by rivers. Sulfate is the key ingredient in hydrogen sulfide formation in the ocean.

Timothy Lyons, a UCR biogeochemist who led the research, explained that the hydrogen sulfide in the ocean is a fingerprint of photosynthetic production of oxygen 2.5 billion years ago.

"A pre-GOE emergence for oxygenic photosynthesis is a matter of intense debate, and its resolution lies at the heart of understanding the evolution of diverse forms of life," he said. "We have found an important piece of that puzzle."

"Our data point to oxygen-producing photosynthesis long before concentrations of oxygen in the atmosphere were even a tiny fraction of what they are today, suggesting that oxygen-consuming chemical reactions were offsetting much of the production," said Reinhard.

The researchers argue that the presence of small amounts of oxygen may have stimulated the early evolution of eukaryotes--organisms whose cells bear nuclei--millions of years prior to the GOE.

"This initial oxygen production set the stage for the development of animals almost two billion years later," Lyons said. "The evolution of eukaryotes had to take place first."

The findings also have implications for the search for life on extrasolar planets.
"Our findings add to growing evidence suggesting that biological production of oxygen is a necessary but not sufficient condition for the evolution of complex life," Reinhard said.

"A planetary atmosphere with abundant oxygen would provide a very promising biosignature.

"But one of the lessons is that just because spectroscopic measurements don't detect oxygen in the atmosphere of another planet, doesn't necessarily mean that no biological oxygen production is taking place."

To analyse the shales, Reinhard first pulverised them into a fine powder in Lyons's laboratory.

Next, the powder was treated with a series of chemicals to extract different minerals. The extracts were then run on a mass-spectrometer.

"One exciting thing about our discovery of sulfidic conditions occurring before the GOE is that it might shed light on ocean chemistry during other periods in the geologic record, such as a poorly understood 400 million-year interval between the GOE and around 1.8 billion years ago," Reinhard said, "a point in time when the deep oceans stopped showing signs of high iron concentrations.

"Now perhaps we have an explanation. If sulfidic conditions could occur with very small amounts of oxygen around, then they might have been even more common and widespread after the GOE."

Said Lyons, "This is important because oxygen-poor and sulfidic conditions almost certainly impacted the availability of nutrients essential to life, such as nitrogen and trace metals. The evolution of the ocean and atmosphere were in a cause-and-effect balance with the evolution of life."

Reinhard and Lyons were joined in the research by Clint Scott of UCR; Ariel Anbar of the Arizona State University, Tempe; and Rob Raiswell of the University of Leeds, UK.

Soil moisture and ocean salinity satellite ready for launch

SMOS Credits: ESA - P. CarrilA new European Earth observation satellite will be launched in the early hours of Monday morning (2 November 2009) from the Plesetsk Cosmodrome in northern Russia.

The European Space Agency (ESA) Soil Moisture & Ocean Salinity (SMOS - pronounced SMOSS) satellite aims to measure both moisture levels in the Earth's soils and the saltiness (salinity) of the surface waters of the world's oceans from space for the very first time. British scientists and engineers have been involved in the mission from the start.

Global measurements of salinity and soil moisture will improve our understanding of how water is transported around the Earth, and how it circulates around the oceans, and lead to more accurate weather forecasts and climate simulations.

Professor Meric Srokosz from the National Oceanography Centre in Southampton – who was part of the international team that first proposed the mission in 1998 – said, "The temperature and salinity of the water in the oceans determine its density, variations in which are important in driving ocean currents. We've been making salinity measurements from ships for many years, but with SMOS we will be able to get a global picture every few days."

"The oceans play a major role in the climate system and possible future changes in currents are important as the oceans interact with the atmosphere, taking up, releasing and re-distributing heat and freshwater. These interactions are key processes affecting both weather and climate," he added.

Professor Robert Gurney from the University of Reading and the National Centre for Earth Observation, who is working on the mission, said, "SMOS will give us global measurements of soil moisture for the very first time. The mission itself is very challenging because it is the first of its type, and allows us to look at a key area of the planet's water cycle. Soil moisture is important for understanding and predicting floods and droughts, and for predicting the future climate."

Dr Phil Newton, NERC's Director of Science Delivery, said, "The great advances in understanding weather, climate and environmental change promised by a successful SMOS mission cannot be achieved by single European nations acting alone. The European Space Agency provides an essential framework for pooling our intellectual, technological and financial resources, so making possible this sort of big science."

The launch of SMOS comes during the build-up to the crucial climate change talks in Copenhagen in December. Director General of the British National Space Centre (BNSC) Dr David Williams said, "SMOS is an important mission with key UK involvement. Satellites such as SMOS are vital for predictions of how our climate is changing and British scientists and engineers are world leaders in using data from space to improve our understanding of the Earth. The recently-opened ESA research facility at Harwell in Oxfordshire will reinforce the UK's focus on climate change research."

SMOS is the second of ESA's Earth Explorer missions and follows the successful launch of the GOCE (Gravity field and steady state Ocean Circulation Explorer) satellite earlier this year.

Climate legislation must address protection of ocean ecosystems

The ocean is on the front lines of climate change, and legislative solutions must include the adaptation and protection against the devastating affects of climate change, said Vikki Spruill, President and CEO of Ocean Conservancy.

Sea-ice is melting, temperatures are rising, and ocean acidification is taking place as the water absorbs the excess carbon dioxide we pump into the atmosphere, she said in a statement in advance of the three-day hearing hosted by the Senate Environment and Public Works Committee.

Climate change is having serious impacts on our ocean. Ocean water is warming. On average, the ocean is a degree warmer than it was a century ago. Another two degrees will devastate many coastal communities, kill the world's coral reefs, and result in mass extinctions of marine life.

"Our ocean is also becoming more acidic. The ocean is full of tiny plants that absorb carbon dioxide and give back oxygen, but excess carbon dioxide in seawater has shifted the basic chemistry of the ocean, causing acidification. A more acidic ocean may pose a serious threat to coral reefs and might even halt the calcifying of shells of marine animals like lobster and clams," she said.

"Particularly vulnerable areas, such as the Arctic, need extra protection. The Arctic region is warming twice as fast as the rest of the planet. The Arctic is Earth’s air conditioner, and changes there affect us all. Industrial demands are growing in the region as sea ice melts due to climate change, but we must take a time out on rapid expansion of the Arctic, until we truly understand what the consequences of our actions will be. Congress has an opportunity to mitigate the damage from climate change by requiring a substantial reduction in greenhouse gases now. Congress can also help ocean ecosystems adapt to climate change, by strengthening laws on how we use the ocean, which will improve the health and resiliency of our ocean so it can withstand stress from climate change.

"Protections are critical. A healthy ocean is essential to our health and the stability of our economy. The ocean is the engine that drives our climate. It provides much of the oxygen we breathe and food we eat. Now is the time to act," concluded Spruill.

Ocean acidification may contribute to global shellfish decline

Stony Brook University researchers find elevated carbon dioxide concentrations impede growth and survival of bivalve larvae

Relatively minor increases in ocean acidity brought about by high levels of carbon dioxide have significant detrimental effects on the growth, development, and survival of hard clams, bay scallops, and Eastern oysters, according to researchers at Stony Brook University's School of Marine and Atmospheric Sciences.

In one of the first studies looking at the effect of ocean acidification on shellfish, Stephanie Talmage, PhD candidate, and Professor Chris Gobler showed that the larval stages of these shellfish species are extremely sensitive to enhanced levels of carbon dioxide in seawater. Their work will be published in the November issue of the journal Limnology and Oceanography.

"In recent decades, we have seen our oceans threatened by overfishing, harmful algal blooms, and warming. Our findings suggest ocean acidification poses an equally serious risk to our ocean resources," said Gobler.

During the past century the oceans absorbed nearly half of atmospheric carbon dioxide derived from human activities such as burning fossil fuels. As the ocean absorbs carbon dioxide it becomes more acidic and has a lower concentration of carbonate, which shell-making organisms use to produce their calcium carbonate structures, such as the shells of shellfish.

In lab experiments, Talmage and Gobler examined the growth and survivorship of larvae from three species of commercially and ecologically valuable shellfish. They raised the larvae in containers bubbled with different levels of carbon dioxide in the range of concentrations that are projected to occur in the oceans during the 21st century and beyond.

Under carbon dioxide concentrations estimated to occur later this century, clam and scallop larvae showed a more than 50 per cent decline in survival. These larvae were also smaller and took longer to develop into the juvenile stage. Oysters also grew more slowly at this level of carbon dioxide, but their survival was only diminished at carbon dioxide levels expected next century.

"The longer time spent in the larval stage is frightening on several levels," said Talmage. "Shellfish larvae are free swimming. The more time they spend in the water column, the greater their risk of being eaten by a predator. A small change in the timing of the larval development could have a large effect on the number of larvae that survive to the juvenile stage and could dramatically alter the composition of the entire population."

Although levels of carbon dioxide in marine environments will continue to rise during this century, organisms in some coastal zones are already exposed to high levels of carbon dioxide due to high levels of productivity and carbon input from sources on land.

"This could be an additional reason we see declines in local stocks of shellfish throughout history," said Talmage. "We've blamed shellfish declines on brown tide, overfishing, and local low-oxygen events. However it's likely that ocean acidification also contributes to shellfish declines."

Talmage and Gobler hope their work might help improve the success rate of shellfish restoration projects.

"On Long Island there are many aquaculturists who restock local waters by growing shellfish indoors at the youngest stages and then release them in local estuaries," said Talmage. "We might be able to advise them on ideal carbon dioxide conditions for growth while larvae are in their facilities, and offer suggestions on release times so that conditions in the local marine environment provide the young shellfish the best shot at survival."