Scientists discover carbonate rocks are unrecognized methane sink

Since the first undersea methane seep was discovered 30 years ago, scientists have meticulously analyzed and measured how microbes in the seafloor sediments consume the greenhouse gas methane as part of understanding how the Earth works.

The sediment-based microbes form an important methane “sink,” preventing much of the chemical from reaching the atmosphere and contributing to greenhouse gas accumulation. As a byproduct of this process, the microbes create a type of rock known as authigenic carbonate, which while interesting to scientists was not thought to be involved in the processing of methane.

That is no longer the case. A team of scientists has discovered that these authigenic carbonate rocks also contain vast amounts of active microbes that take up methane. The results of their study, which was funded by the National Science Foundation, were reported today in the journal Nature Communications.

“No one had really examined these rocks as living habitats before,” noted Andrew Thurber, an Oregon State University marine ecologist and co-author on the paper. “It was just assumed that they were inactive. In previous studies, we had seen remnants of microbes in the rocks – DNA and lipids – but we thought they were relics of past activity. We didn’t know they were active.

“This goes to show how the global methane process is still rather poorly understood,” Thurber added.

Lead author Jeffrey Marlow of the California Institute of Technology and his colleagues studied samples from authigenic compounds off the coasts of the Pacific Northwest (Hydrate Ridge), northern California (Eel River Basin) and central America (the Costa Rica margin). The rocks range in size and distribution from small pebbles to carbonate “pavement” stretching dozens of square miles.

“Methane-derived carbonates represent a large volume within many seep systems and finding active methane-consuming archaea and bacteria in the interior of these carbonate rocks extends the known habitat for methane-consuming microorganisms beyond the relatively thin layer of sediment that may overlay a carbonate mound,” said Marlow, a geobiology graduate student in the lab of Victoria Orphan of Caltech.

These assemblages are also found in the Gulf of Mexico as well as off Chile, New Zealand, Africa, Europe – “and pretty much every ocean basin in the world,” noted Thurber, an assistant professor (senior research) in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

The study is important, scientists say, because the rock-based microbes potentially may consume a huge amount of methane. The microbes were less active than those found in the sediment, but were more abundant – and the areas they inhabit are extensive, making their importance potential enormous. Studies have found that approximately 3-6 percent of the methane in the atmosphere is from marine sources – and this number is so low due to microbes in the ocean sediments consuming some 60-90 percent of the methane that would otherwise escape.

Now those ratios will have to be re-examined to determine how much of the methane sink can be attributed to microbes in rocks versus those in sediments. The distinction is important, the researchers say, because it is an unrecognized sink for a potentially very important greenhouse gas.

“We found that these carbonate rocks located in areas of active methane seeps are themselves more active,” Thurber said. “Rocks located in comparatively inactive regions had little microbial activity. However, they can quickly activate when methane becomes available.

“In some ways, these rocks are like armies waiting in the wings to be called upon when needed to absorb methane.”

The ocean contains vast amounts of methane, which has long been a concern to scientists. Marine reservoirs of methane are estimated to total more than 455 gigatons and may be as much as 10,000 gigatons carbon in methane. A gigaton is approximate 1.1 billion tons.

By contrast, all of the planet’s gas and oil deposits are thought to total about 200-300 gigatons of carbon.

Lessons learned from oil rig disaster

The Deepwater Horizon oil rig explosion in the Gulf of Mexico on April 20 triggered one of history’s biggest oil spills at sea. Eleven people lost their lives in the accident. Here the beaches are being cleared. (Photo: BP)
The Deepwater Horizon oil rig explosion in the Gulf of Mexico on April 20 triggered one of history’s biggest oil spills at sea. Eleven people lost their lives in the accident. Here the beaches are being cleared. (Photo: BP)

When interviewed by the BBC, the now retired BP boss Tony Hayward admitted to his company’s insufficient response to the Deepwater Horizon rig accident in the Gulf of Mexico. Could the company have been better prepared for what turned out to be one of the biggest oil disasters in history?

“We were making it up day to day,” Hayward said of BP’s rescue plan. Together with chairman of the board, Carl-Henrik Svenberg, he was held responsible for 11 dead and 17 injured workers. According to the New York Times, five million barrels of oil leaked into the ocean outside the coast of Louisiana between April and August 2010.

A lack of safety procedures was identified by the oil spill investigation commission, set up by President Barack Obama, as a determining factor behind the disaster. The three companies involved in the accident – BP, Transocean and Halliburton – were all accused of having cut corners in order to complete the well. At the time of the blow-out, this job was five weeks behind schedule. Five survivors talked to CNN about a corporate culture in which safety warnings were routinely ignored.

“Major accidents such as the Deepwater Horizon disaster in the Gulf of Mexico could also happen in the North Sea,” says Preben Lindøe, professor of societal safety and security at the University of Stavanger, Norway.

“But strong, organizational barriers between the oil industry, trade unions and the Petroleum Safety Authority Norway reduce the risk,” he adds.

Together with his colleague, associate professor Ole Andreas Engen, he is part of the Robust Regulation in the Petroleum Sector team. The four-year research project, funded by the Norwegian Research Council, also involve the independent research group Sintef and the University of Oslo, in addition to legal expertise affiliated with Boston university.

Different practice

The researchers compare oil industry regulation in the USA, Great Britain and Norway.

“There are hardly any unions in the Gulf of Mexico. Tripartite collaboration, as it is practiced on the Norwegian continental shelf, is therefore impossible,” says Lindøe.

The US regulator, Minerals Management Service, carries out inspections based on a fairly meticulous body of rules. Inspectors are transported to offshore installations, equipped with long and detailed check lists.

By comparison, Norwegian regulation is based on internal control. The authorities thereby rely on the companies administering their safety work themselves. While the Norwegian model is based on trust – built up over time – and the sharing of experience and information, the situation in the US is almost the opposite, according to Lindøe.

“The reason this model has succeeded in Norway, is because the parties have been able to fill the concept of internal control with substance. Both employers and unions are involved in developing industrial standards and good practice which can be adhered to,” he says.

Close shave in the North Sea

But recent near-accidents in Norway may potentially have become disasters. In May 2010, Norwegian oil major Statoil had problems during drilling operations at its Gullfaks field in the North Sea. While drilling a well from the Gullfaks C installation, gas entered the well and reached the platform deck. According to the company’s investigation report, only luck prevented the incident from becoming a much more complicated subsea blowout.

The Petroleum Safety Authority shared this conclusion, and pointed out that the incident could easily have evolved into a disaster. It issued four enforcement notices to Statoil, and the company was reported to the police by environmental group Bellona. International media compared the Gullfaks incident to the Deepwater Horizon accident.

“The public’s attention is triggered by such incidents, and we are made aware of society’s unpredictability. When perceived threats are referred to by the media, societal safety is pushed up on the agenda. The attention paid to this subject varies, which lies in its nature. When safety work succeeds, its success is proved by the non-occurrence of serious incidents. When nothing happens, we may become less attentive and sloppier in adhering to routines and procedures,” says Ole Andreas Engen.

“When attention fades, accidents happen more easily, and are followed by increased awareness. Societal safety is thus a perpetual Sisyphus effort. It is a big challenge for all organizations to maintain a high level of safety awareness over time,” he says.

Robust regulation

The researchers point to another example: A gas leak at the North Sea field Snorre in 2004, when an accident equivalent to Deepwater Horizon was only a spark away. But in spite of a number of near-accidents, Norwegian regulation is still more robust than the US’.

The petroleum industry in Norway has gone through several critical phases in its history. Gradually, the parties involved have learned to trust each other. A robust system like this is able to withstand a blow. This is not the case in the USA, where the authorities have a much more difficult task in monitoring regulations. There are strict requirements for new regulations to undergo cost-benefit analyses, which must be submitted to the President’s office, the researchers explain.

Moreover, the regulation of safety and the work environment is divided between two governmental agencies. The US Coast Guard is the controlling authority of personnel safety on offshore platforms, says Lindøe.

“Workers don’t enjoy the same legitimacy with regard to their role in safety work as they do in Norway,” he adds.

According to Lindøe and Engen, it is common practice in the US to look for scapegoats, and pin the blame for accidents on them, instead of changing the systems. In Norway, the parties are more likely to come together to find out how systems and routines may have contributed to an employee making a mistake. The researcher sum up the lessons learned after the Gulf of Mexico disaster:

“The Deepwater Horizon accident has uncovered some evident weaknesses within US safety regulation. The Government being restrained from intervening directly with the industry is one of them. To the Norwegian industry, this accident and the near-accident on Gullfaks C, should serve as reminders of the importance of maintaining the foundation pillars of the Norwegian safety management system: Effective and well qualified authorities, and clear guidelines for cooperation and trust between the parties,” Lindøe concludes.

Scientists find methane gas concentrations have returned to near-normal levels

UCSB graduate student Stephanie Mendes, left, and postdoctoral researcher Molly Redmond are sampling water. -  Texas A&M University and NOAA
UCSB graduate student Stephanie Mendes, left, and postdoctoral researcher Molly Redmond are sampling water. – Texas A&M University and NOAA

Calling the results “extremely surprising,” researchers from the University of California, Santa Barbara and Texas A&M University report that methane gas concentrations in the Gulf of Mexico have returned to near normal levels only months after a massive release occurred following the Deepwater Horizon oil rig explosion.

Findings from the research study, led by oceanographers John Kessler of Texas A&M and David Valentine of UCSB, were published today in Science Xpress, in advance of their publication in the journal Science. The findings show that Mother Nature quickly saw to the removal of more than 200,000 metric tons of dissolved methane through the action of bacteria blooms that completely consumed the immense gas plumes the team had identified in mid-June. At that time, the team reported finding methane gas in amounts 100,000 times above normal levels. But, about 120 days after the initial spill, they could find only normal concentrations of methane and clear evidence of complete methane respiration.

“What we observed in June was a horizon of deep water laden with methane and other hydrocarbon gases,” Valentine said. “When we returned in September and October and tracked these waters, we found the gases were gone. In their place were residual methane-eating bacteria, and a 1 million ton deficit in dissolved oxygen that we attribute to respiration of methane by these bacteria.”

Kessler added: “Based on our measurements from earlier in the summer and previous other measurements of methane respiration rates around the world, it appeared that (Deepwater Horizon) methane would be present in the Gulf for years to come. Instead, the methane respiration rates increased to levels higher than have ever been recorded, ultimately consuming it and prohibiting its release to the atmosphere.”

While the scientists’ research documents the changing conditions of the Gulf waters, it also sheds some light on how the planet functions naturally.

“This tragedy enabled an impossible experiment,” Valentine said, “one that allowed us to track the fate of a massive methane release in the deep ocean, as has occurred naturally throughout Earth’s history.”

Kessler noted: “We were glad to have the opportunity to lend our expertise to study this oil spill. But also we tried to make a little good come from this disaster and use it to learn something about how the planet functions naturally. The seafloor stores large quantities of methane, a potent greenhouse gas, which has been suspected to be released naturally, modulating global climate. What the Deepwater Horizon incident has taught us is that releases of methane with similar characteristics will not have the capacity to influence climate.”

The Deepwater Horizon offshore drilling platform exploded on April 20, 2010, about 40 miles off the Louisiana coast. The blast killed 11 workers and injured 17 others. Oil was gushing from the site at the rate of 62,000 barrels per day, eventually spilling an estimated 170 million gallons of oil into the Gulf. The leak was capped on July 15, and the well was permanently sealed on Sept. 19.

The research team collected thousands of water samples at 207 locations covering an area of about 36,000 square miles. The researchers based their conclusions on measurements of dissolved methane concentrations, dissolved oxygen concentrations, methane oxidation rates, and microbial community structure.

Florida institutions to host Gulf of Mexico oil spill conference

The University of South Florida, Florida Institute of Oceanography, Mote Marine Laboratory, and the State of Florida Oil Spill Academic Task Force will host a major oil spill research conference, February 9-11, 2011, at the Hilton St. Petersburg Bayfront in St. Petersburg, Florida.

Oral or poster presentations are invited on substantial and original research on all aspects of the Gulf Oil Spill disaster and its impact. Abstract submission deadline is October 25, 2010. Abstracts may be submitted online at http://oilspill.usf.edu/.

The Deepwater Horizon Oil Spill will forever change the Gulf of Mexico, significantly impacting its citizens, environment, economy and policy of the region-and beyond. As efforts are considered to mitigate effects of the spill, plans must also be made to prepare for a different Gulf of Mexico -5, 10 and 20 years out. This disaster is of global importance and demands new approaches and methods, as well as the shared experience and insight of those who have been engaged in such disasters world-wide (e.g., from Alaska, Brazil, India, Europe, Saudi Arabia, Mexico, Nigeria). One goal is to ensure that the tools and models are in place to deal with similar crises globally.

To deliberate these issues, the conference will bring together representatives from academia, government, NGOs and the private sector to inform each other about the state of research in relevant topical areas and to translate research into policy and management for predicting and adapting to a changed future, the extent of which is unknown.

Key topics will include:

  • Geotechnical Engineering
  • Regional Oceanography
  • Chemical Weathering – Biological Consumption
  • Dispersants
  • Ecological Consequences and Toxicity
  • Economic and Social Impacts
  • Human Health Issues
  • Stakeholders, Science and Policy

The conference co-chairs are Robert H. Weisberg, Distinguished University Professor of Physical Oceanography, University of South Florida; William T. Hogarth, Dean, USF College of Marine Science and Acting Director Florida Institute of Oceanography; and Michael P. Crosby, Senior Vice President for Research, Mote Marine Laboratory.

Oil remains below surface, will come ashore in pulses

Gregory Stone, director of LSU’s WAVCIS Program and also of the Coastal Studies Institute in the university’s School of the Coast & Environment, disagrees with published estimates that more than 75 percent of the oil from the Deepwater Horizon incident has disappeared.

Stone recently participated in a three-hour flyover of the affected area in the Gulf, where he said that subsurface oil was easily visible from overhead.

“It’s most definitely there,” said Stone. “It’s just a matter of time before it makes itself known again.”

Readings from WAVCIS indicate that the direction of the ocean currents near the middle and bottom of the water column are aimed offshore; in other words, this submerged oil will be pushed out to sea, where it will then rise higher into the water column and be washed onto land, particularly during storms.

“It is going to come on shore not consistently, but rather in pulses because it is beneath the surface,” he said. “You may get one or two, maybe even five or 10 waves coming ashore with absolutely no oil ? but eventually, it’s going to come ashore.” He also cautions that whatever oil doesn’t remain suspended in the water column may simply sit atop the seafloor, waiting to be mixed back into the currents.

“It will simply be stirred up during rough seas or changing currents and reintroduced into the water column,” he explained.

Another timely concern is hurricane season since September is generally one of the most active months of the year. “Storm surge, when combined with storm waves from a hurricane, could stir up this submerged oil and bring it – lots of it – onshore and into the wetlands,” Stone said. “Even a tropical storm could result in more oil on the shoreline. And that’s a reality we need to consider and be prepared for.”

Formally known as the Wave-Current-Surge Information System, WAVCIS is based off of a network of buoys, oil platforms sensors and ADCPs, or Acoustic Doppler Current Profilers, in the Gulf of Mexico. The ADCPs are exceptionally sensitive. Housed on the seafloor, they send acoustic signals up to the surface of the water, measuring the entire water column for everything from current direction to speed and temperature. It’s also integrated with the National Data Buoy Center, or NDBC, system, providing researchers worldwide with a comprehensive look at the Gulf environment, which is an invaluable research tool during the inevitable hurricane season, and also during disasters such as the Deepwater Horizon tragedy.

“WAVCIS is among the most sensitive ocean observing systems in the entire nation,” said Stone. “We measure a wide variety of physical parameters at the water surface, water column and on the sea bed. This information is extremely helpful in predicting or determining where the oil is – and where it’s going to go. Because our information is updated hourly and available to the public, our lab has played a primary role in providing facts about the situation surrounding the oil’s movement and location.”

Stone, whose experience with WAVCIS has spanned everything from natural to manmade disasters, knows that only time will tell the severity of the oil’s impact.

“This is a long term problem. It’s not simply going to go away. I was in Prince William Sound 10 years after the Exxon-Valdez event, and when I lifted up a rock, there was still residual oil beneath it,” he said. “Thus, the residence time of oil in the coastal environment can be substantial, although ecosystem conditions along the northern Gulf are very different and will likely recover quicker than in Alaska. We here at WAVCIS can at least track Gulf conditions to monitor the situation as closely as possible.

Study shows deepwater oil plume in Gulf degraded by microbes

In the aftermath of the explosion of BP’s Deepwater Horizon drilling rig in the Gulf of Mexico, a dispersed oil plume was formed at a depth between 3,600 and 4,000 feet and extending some 10 miles out from the wellhead. An intensive study by scientists with the Lawrence Berkeley National Laboratory (Berkeley Lab) found that microbial activity, spearheaded by a new and unclassified species, degrades oil much faster than anticipated. This degradation appears to take place without a significant level of oxygen depletion.

“Our findings show that the influx of oil profoundly altered the microbial community by significantly stimulating deep-sea psychrophilic (cold temperature) gamma-proteobacteria that are closely related to known petroleum-degrading microbes,” says Terry Hazen, a microbial ecologist with Berkeley Lab’s Earth Sciences Division and principal investigator with the Energy Biosciences Institute, who led this study. “This enrichment of psychrophilic petroleum degraders with their rapid oil biodegradation rates appears to be one of the major mechanisms behind the rapid decline of the deepwater dispersed oil plume that has been observed.”

The uncontrolled oil blowout in the Gulf of Mexico from BP’s deepwater well was the deepest and one of the largest oil leaks in history. The extreme depths in the water column and the magnitude of this event posed a great many questions. In addition, to prevent large amounts of the highly flammable Gulf light crude from reaching the surface, BP deployed an unprecedented quantity of the commercial oil dispersant COREXIT 9500 at the wellhead, creating a plume of micron-sized petroleum particles. Although the environmental effects of COREXIT have been studied in surface water applications for more than a decade, its potential impact and effectiveness in the deep waters of the Gulf marine ecosystem were unknown.

Analysis by Hazen and his colleagues of microbial genes in the dispersed oil plume revealed a variety of hydrocarbon-degraders, some of which were strongly correlated with the concentration changes of various oil contaminants. Analysis of changes in the oil composition as the plume extended from the wellhead pointed to faster than expected biodegradation rates with the half-life of alkanes ranging from 1.2 to 6.1 days.

“Our findings, which provide the first data ever on microbial activity from a deepwater dispersed oil plume, suggest that a great potential for intrinsic bioremediation of oil plumes exists in the deep-sea,” Hazen says. “These findings also show that psychrophilic oil-degrading microbial populations and their associated microbial communities play a significant role in controlling the ultimate fates and consequences of deep-sea oil plumes in the Gulf of Mexico.”

The results of this research were reported in the journal Science (August 26, 2010 on-line) in a paper titled “Deep-sea oil plume enriches Indigenous oil-degrading bacteria.” Co-authoring the paper with Hazen were Eric Dubinsky, Todd DeSantis, Gary Andersen, Yvette Piceno, Navjeet Singh, Janet Jansson, Alexander Probst, Sharon Borglin, Julian Fortney, William Stringfellow, Markus Bill, Mark Conrad, Lauren Tom, Krystle Chavarria, Thana Alusi, Regina Lamendella, Dominique Joyner, Chelsea Spier, Jacob Baelum, Manfred Auer, Marcin Zemla, Romy Chakraborty, Eric Sonnenthal, Patrik D’haeseleer, Hoi-Ying Holman, Shariff Osman, Zhenmei Lu, Joy Van Nostrand, Ye Deng, Jizhong Zhou and Olivia Mason.

Hazen and his colleagues began their study on May 25, 2010.

At that time, the deep reaches of the Gulf of Mexico were a relatively unexplored microbial habitat, where temperatures hover around 5 degrees Celsius, the pressure is enormous, and there is normally little carbon present.

“We deployed on two ships to determine the physical, chemical and microbiological properties of the deepwater oil plume,” Hazen says. “The oil escaping from the damaged wellhead represented an enormous carbon input to the water column ecosystem and while we suspected that hydrocarbon components in the oil could potentially serve as a carbon substrate for deep-sea microbes, scientific data was needed for informed decisions.”

Hazen, who has studied numerous oil-spill sites in the past, is the leader of the Ecology Department and Center for Environmental Biotechnology at Berkeley Lab’s Earth Sciences Division. He conducted this research under an existing grant he holds with the Energy Biosciences Institute (EBI) to study microbial enhanced hydrocarbon recovery. EBI is a partnership led by the University of California (UC) Berkeley and including Berkeley Lab and the University of Illinois that is funded by a $500 million, 10-year grant from BP.

Results in the Science paper are based on the analysis of more than 200 samples collected from 17 deepwater sites between May 25 and June 2, 2010. Sample analysis was boosted by the use of the latest edition of the award-winning Berkeley Lab PhyloChip – a unique credit card-sized DNA-based microarray that can be used to quickly, accurately and comprehensively detect the presence of up to 50,000 different species of bacteria and archaea in a single sample from any environmental source, without the need of culturing. Use of the Phylochip enabled Hazen and his colleagues to determine that the dominant microbe in the oil plume is a new species, closely related to members of Oceanospirillales family, particularly Oleispirea antarctica and Oceaniserpentilla haliotis.

Hazen and his colleagues attribute the faster than expected rates of oil biodegradation at the 5 degrees Celsius temperature in part to the nature of Gulf light crude, which contains a large volatile component that is more biodegradable. The use of the COREXIT dispersant may have also accelerated biodegradation because of the small size of the oil particles and the low overall concentrations of oil in the plume. In addition, frequent episodic oil leaks from natural seeps in the Gulf seabed may have led to adaptations over long periods of time by the deep-sea microbial community that speed up hydrocarbon degradation rates.

One of the concerns raised about microbial degradation of the oil in a deepwater plume is that the microbes would also be consuming large portions of oxygen in the plume, creating so-called “dead-zones” in the water column where life cannot be sustained. In their study, the Berkeley Lab researchers found that oxygen saturation outside the plume was 67-percent while within the plume it was 59-percent.

“The low concentrations of iron in seawater may have prevented oxygen concentrations dropping more precipitously from biodegradation demand on the petroleum, since many hydrocarbon-degrading enzymes have iron as a component,” Hazen says. “There’s not enough iron to form more of these enzymes, which would degrade the carbon faster but also consume more oxygen.”

Deep plumes of oil could cause dead zones in the Gulf

A new simulation of oil and methane leaked into the Gulf of Mexico suggests that deep hypoxic zones or “dead zones” could form near the source of the pollution. The research investigates five scenarios of oil and methane plumes at different depths and incorporates an estimated rate of flow from the Deepwater Horizon spill, which released oil and methane gas into the Gulf from April to mid July of this year.

A scientific paper on the research has been accepted for publication by Geophysical Research Letters, a journal of the American Geophysical Union,

Scientists at the National Oceanic and Atmospheric Administration (NOAA) and Princeton University conducted the research. Based on their simulations, they conclude that the ocean hypoxia or toxic concentrations of dissolved oil arising from the Deepwater Horizon blowout are likely to be “locally significant but regionally confined to the northern Gulf of Mexico.”

A hypoxic or “dead” zone is a region of ocean where oxygen levels have dropped too low to support most forms of life, typically because microbes consuming a glut of nutrients in the water use up the local oxygen as they consume the material.

“According to our simulations, these hypoxic areas will be peaking in October,” says study coauthor Robert Hallberg of the NOAA Geophysical Fluid Dynamics Laboratory in Princeton, N.J.. “Oxygen drawdown will go away slowly, as the tainted water is mixed with Gulf waters that weren’t affected. We’re estimating a couple of years” before the dead zone has dissipated, he adds.

Although the Princeton-NOAA study was carried out when the flow rate from the Deepwater Horizon spill was still underestimated, the simulated leak lasted longer than did the actual spill. Consequently, says Alistair Adcroft of Princeton University and the NOAA Geophysical Fluid Dynamics Laboratory, another study coauthor, “the overall impact on oxygen turns out to be about the same” as would be expected from the Deepwater Horizon spill.

Study probes mystery of loop current in eastern Gulf of Mexico

A study released by the Minerals Management Service today examines the circulation in the Eastern Gulf of Mexico (GOM) and sheds new light on the behavior of the Loop Current (LC) and Loop Current Eddies (LCEs), the relation between the upper- and lower-layer currents, and the variability of water mass characteristics in deepwater.

When the LC and the LCE are present in the Gulf near oil and gas activities, operators may have to curtail or amend their operations due to the strength of the current or eddy.

“The observations from this study will help MMS and other scientists better understand the Loop Current and improve our forecasting of its behavior in the Gulf of Mexico,” said Dr. Alexis Lugo-Fernandez, the MMS physical oceanographer responsible for the study. “This is important because oil and gas activities in the deepwater Gulf are affected by the presence of the Loop Current and the Loop Current Eddies.”

Prepared under a cooperative agreement by Louisiana State University’s Coastal Marine Institute, Observation of the Deepwater Manifestation of the Loop Current and Loop Current Rings in the Eastern Gulf of Mexico chronicled the deployment in the Eastern Gulf of a deepwater mooring cable measuring more than 11,800 feet for two years. The study supplements information gathered from a previous three year deployment.

The mooring data suggest the LC and LCEs that dominate upper-layer circulation in the Eastern GOM also influence the deeper currents in the Eastern GOM.

Dr. Lugo-Fernandez noted that a method to transmit significant energy in the form of heat to deep water in the GOM during the 2005 hurricane season was observed during this study. As sea levels rise near the center of tropical storms, the resulting higher pressure causes a small but measurable increase in temperature at all water depths. He explained that “Simply due to the large number of storm occurrences within the GOM, these findings represent an important process for transmitting energy to the deepwater.”