Posts Tagged ‘florida state university’

Warming climate may release vast amounts of carbon from long-frozen Arctic soils

April 24, 2015

While climatologists are carefully watching carbon dioxide levels in the atmosphere, another group of scientists is exploring a massive storehouse of carbon that has the potential to significantly affect the climate change picture.

Aron Stubbins

Aron Stubbins

University of Georgia Skidaway Institute of Oceanography researcher Aron Stubbins is part of a team investigating how ancient carbon, locked away in Arctic permafrost for thousands of years, is now being transformed into carbon dioxide and released into the atmosphere. The results of the study were published in Geophysical Research Letters.

The Arctic contains a massive amount of carbon in the form of frozen soil—the remnants of plants and animals that died more than 20,000 years ago. Because this organic material was permanently frozen year-round, it did not undergo decomposition by bacteria the way organic material does in a warmer climate. Just like food in a home freezer, it has been locked away from the bacteria that would otherwise cause it to decay and be converted to carbon dioxide.

“However, if you allow your food to defrost, eventually bacteria will eat away at it, causing it to decompose and release carbon dioxide,” Stubbins said. “The same thing happens to permafrost when it thaws.”

Scientists estimate there is more than 10 times the amount of carbon in the Arctic soil than has been put into the atmosphere by burning fossil fuels since the start of the Industrial Revolution. To look at it another way, scientists estimate there is two and a half times more carbon locked away in the Arctic deep freezer than there is in the atmosphere today. Now, with a warming climate, that deep freezer is beginning to thaw and that long-frozen carbon is beginning to be released into the environment.

“The study we did was to look at what happens to that organic carbon when it is released,” Stubbins said. “Does it get converted to carbon dioxide or is it still going to be preserved in some other form?”

Stubbins and his colleagues conducted their fieldwork at Duvanni Yar in Siberia. There, the Kolyma River carves into a bank of permafrost, exposing the frozen organic material. This worked well for the scientists, as they were able to find streams that consisted of 100 percent thawed permafrost. The researchers measured the carbon concentration, how old the carbon was and what forms of carbon were present in the water. They bottled it with a sample of the local microbes. After two weeks, they measured the changes in the carbon concentration and composition and the amount of carbon dioxide that had been produced.

A bank of permafrost thaws near the Kolyma River in Siberia.

“We found that decomposition converted 60 percent of the carbon in the thawed permafrost to carbon dioxide in two weeks,” Stubbins said. “This shows the permafrost carbon is definitely in a form that can be used by the microbes.”

Lead author Robert Spencer of Florida State University added, “Interestingly, we also found that the unique composition of thawed permafrost carbon is what makes the material so attractive to microbes.”

The study also confirmed what the scientists had suspected: The carbon being used by the bacteria is at least 20,000 years old. This is significant because it means that carbon has not been a part of the global carbon cycle in the recent past.

“If you cut down a tree and burn it, you are simply returning the carbon in that tree to the atmosphere where the tree originally got it,” Stubbins said. “However, this is carbon that has been locked away in a deep-freeze storage for a long time.

“This is carbon that has been out of the active, natural system for tens of thousands of years. To reintroduce it into the contemporary system will have an effect.”

The carbon release has the potential to create what scientists call a positive feedback loop. This means as more carbon is released into the atmosphere, it would amplify climate warming. That, in turn, would cause more permafrost to thaw and release more carbon, causing the cycle to continue.

“Currently, this is not a process that shows up in future (Intergovernmental Panel on Climate Change) climate projections; in fact, permafrost is not even accounted for,” Spencer said.

“Moving forward, we need to find out how consistent our findings are and to work with a broader range of scientists to better predict how fast this process will happen,” Stubbins said.

In addition to Stubbins and Spencer, the research team included Paul Mann from Northumbria University, United Kingdom; Thorsten Dittmar from the University of Oldenburg, Germany; Timothy Eglinton and Cameron McIntyre from the Geological Institute, Zurich, Switzerland; Max Holmes from Woods Hole Research Center; and Nikita Zimov from the Far-Eastern Branch of the Russian Academy of Science.

Research cruising across the Pacific

November 4, 2013

UGA Skidaway Institute professor Cliff Buck is on a lengthy research cruise from Peru to Tahiti. Here is the second entry to is log of his experience.

Ahoy There!

Current Position: S 12.0449 W 77.3761

After 68 hours on location, we are finally leaving our first hydrographic station. A hydrographic station is a location that is chosen for intensive study. We will occupy 35 such stations over the course of the next two months and will use the data we collect at each to learn about the distributions of trace elements and isotopes (TEIs) in this region of the Pacific. We also measure basic parameters like temperature, conductivity/salinity, pressure, density, fluorescence and dissolved oxygen as these measurements can tell us about the movement of water masses within the ocean’s interior and help us interpret our chemical information.

We collect seawater and deploy sensors using plastic bottles mounted on a titanium frame called a rosette. The rosette is suspended from a sheathed Kevlar line which contains conducting wires that allow the transmission of signals between the surface and the rosette. In this way, we can monitor the depth of the bottles and can send them commands to close at specific depths. On this cruise, we are deploying a rosette able to hold 24 12-liter bottles, for a total of 288 liters of water on each cast

The GEOTRACES rosette being lowered over the side of the ship. The gray sampling bottles can be seen mounted on the titanium frame.

The GEOTRACES rosette being lowered over the side of the ship. The gray sampling bottles can be seen mounted on the titanium frame.

The entire package weighs approximately 1,600 pounds including the weight of the rosette, bottles, and sensors. The bottles are specially made of Teflon-lined plastic and contain no metal whatsoever to reduce the possibility that the sampling system will contaminate the seawater inside. The bottles can be detached from the rosette and carried into a clean sampling laboratory on board to reduce the possibility of contaminating the water inside. Once inside the lab, the water is filtered and stored in specially prepared plastic containers and bottles for either analysis on the ship or back on shore.

In addition to the rosette sampling system which brings seawater to the surface, a group of scientists from the Woods Hole Oceanographic Institution is deploying pumps that are able to operate to a depth of 5500 meters. These pumps are battery powered and are suspended from a wire lowered over the side. Their purpose is to filter 1200-1500 liters of seawater and to collect the microscopic particles which are present everywhere in the ocean. These particles have isotopic signatures that provide clues as to the circulation of the oceans and the rates at which particles sink from the surface ocean to the bottom. In the case of our first station, the bottom was 5500 meters (that’s 18,000 feet) beneath the ship’s keel.

My work, along with collaborators Dr. William Landing from Florida State University and Dr. Ana Aguilar-Islas of the University of Alaska – Fairbanks, is targeted on the input of TEIs to the surface of the ocean by atmospheric deposition. The atmosphere is full of small particles called aerosols which can include emissions from industrial processes as well as dust blown off of the continents. These particles can settle on the ocean’s surface by dry deposition or become incorporated into rain droplets and be scavenged from the atmosphere in wet deposition. We have installed four aerosol samplers on the highest deck of the ship which run vacuum motors pulling air through filters.

The four aerosol samplers can be seen in the foreground. The sampling filters are protected from sea spray and rain by the roof-like shrouds that give the samplers the appearance of birdhouses. The rain samplers are mounted in the background.

The four aerosol samplers can be seen in the foreground. The sampling filters are protected from sea spray and rain by the roof-like shrouds that give the samplers the appearance of birdhouses. The rain samplers are mounted in the background.

The aerosol particles are impacted onto these filters giving us a means to characterize their chemical composition and estimate deposition rates. We have also deployed two automated rain samplers which open and uncover their sampling buckets when their sensors detect rain. Any rain collected will be analyzed for a wide range of TEIs.

Taken together, these research programs will provide us with a better understanding of the chemical processes at work in the eastern Pacific Ocean.

For more information about Dr. Buck’s work, you can visit his Web page on the Skidaway Institute Web site.

Skidaway Institute scientists cruise Florida’s ‘Big Bend’

December 7, 2010

“It’s a really exciting place to do oceanography, because you can throw almost any kind of instrument over the side, and it will come up with observations that lead to new science,” said Skidaway Institute scientist Catherine Edwards. A former postdoctoral fellow at Florida State University, Edwards describes her recent research cruise to the little-studied “Big Bend” section of the northeastern Gulf of Mexico.

One of Skidaway Institute’s instrument packages is lowered into the water.

In an effort to extend FSU’s coastal ocean observatory in the Florida Big Bend, Edwards deployed two self-contained bottom-mounted sensors that measure temperature, salinity, currents, and how they vary from the seafloor to the surface. The sensor packages are moored on the outer shelf to help Edwards and FSU scientists learn more about how the Gulf wind and tidal currents transport material from the shelf edge to the shore. Edwards was assisted by Austin Todd, a graduate student in physical oceanography at Florida State University.

Catherine Edwards with FSU graduate student Austin Todd and one of the instrument packages.

Many fish are spawned at the shelf break, but spend their juvenile stages in the salt marshes and estuaries. Distances of 50 to 75 miles are too far for fish larvae to swim on their own and physical models, by themselves, do not fully explain how larvae are able make the journey.

“Whether you’re tracking fish larvae or oil, the science question is the same,” Edwards said. “We are trying to develop a clearer picture of how the physics and biology interact.”

Edwards does have an idea. Coastal sea breezes shift on- and off-shore between day and night during spawning season in the Gulf of Mexico. The winds push the surface water in one direction, while deeper waters compensate with currents in the opposite direction.

“Fish larvae don’t swim far horizontally, but they do migrate up and down the water column on day-night cycles fundamentally tied to the timing of the solar cycle and thus sea breeze,” Edwards said. “Depending on the larval migration, they may simply shift their position in the water column to ride the diurnal shifts in the current to shore.”

The cruise wasn’t easy to arrange. Edwards had access to the needed instruments, but no money for ship-time, which often runs thousands to tens of thousands of dollars a day for capable oceanographic vessels. She was able to hitch a ride on a NOAA National Marine Fisheries Service (NMFS) vessel that was conducting a twice-annual cruise to studying fish biology throughout the Gulf of Mexico.

“I’m a physicist by training, so I really enjoyed the chance to ‘play biologist’ for the two week leg of the cruise,” she said. “That interaction was really valuable for planning future work with NMFS scientists.”

Edwards set up two sets of instruments very near a NOAA weather buoy. While the weather buoy collects data on the conditions above the surface, Edwards’ instruments will do the same for the conditions in the water column. Since weather conditions often drive water movement, the ability to combine the two data sets will provide valuable information.

Edwards will return in six months to collect her instrument packages and the data they have recorded.

Catherine Edwards joins Skidaway Institute

July 26, 2010

Physical oceanographer Catherine Edwards has joined the faculty of the Skidaway Institute of Oceanography as an assistant professor.

Edwards  received both her bachelor’s degree in physics and her doctorate in physical oceanography from the University of North Carolina at Chapel Hill. She recently completed a postdoctoral fellowship at Florida State University.

Edwards is a coastal physical oceanographer with research interests in shelf-scale and nearshore processes. Her work includes modeling and observing coastal tidal, wind-forced, and density driven-dynamics, as well as coastal meteorology and air-sea interaction.

Edwards’ current projects include larval transport mechanisms for fisheries in the northeast Gulf of Mexico; the interaction of high frequency winds and currents in the South Atlantic Bight and Gulf of Mexico; tide-correlated eddies near the Gulf Stream; and the processes that transport nutrients and biomass onto the shelf of the South Atlantic Bight.