Tag Archives: nsf

NSF grant funds Diaz’s research

Julia Diaz

UGA Skidaway Institute researcher Julia Diaz is the lead scientist on a $852,906 three-year grant from the National Science Foundation titled “Collaborative Research: Assessing the role of compound specific phosphorus hydrolase transformations in the marine phosphorus cycle.” Diaz and her colleague, Solange Duhamel from the Lamont-Doherty Earth Observatory of Columbia University, will study how phytoplankton cope with shortages of phosphorus in the ocean, and if phytoplankton in phosphorus-rich environments also exhibit some of the same strategies. Skidaway Institute’s share of the grant is $296,831 and the funding began on Sept. 1, 2017.

Advertisements

UGA Skidaway Institute scientist to spend winter 2020 locked in Arctic ice

Cliff Buck

Spending the Christmas holidays and the better part of January and February on a ship frozen solid in the Arctic ice cap isn’t most people’s idea of a great way to spend the winter. However, University of Georgia Skidaway Institute of Oceanography scientist Cliff Buck is planning to do just that. Buck is part of a major, international research project named Multidisciplinary drifting Observatory for the Study of Arctic Climate or “MOSAiC.” The goal of the project is to sail the German ice breaker Research Vessel Polarstern into the Arctic Ocean until it becomes locked in the ice and leave it there for a year, all the while using it as a headquarters for scientists to study Arctic climate change.

Climate change is occurring at a higher rate in the Arctic than in other regions. That rate of change is not reflected well in climate change models, mostly due to the lack of year-round observations in the Arctic.

“We care about this because the Arctic is turning out to be one of the more sensitive parts of the planet when it comes to climate change,” Buck said. “It’s warming at rates much higher than other parts of the world, and as it warms, many things are happening, such as the reduction in the expanse of sea ice.”

Those changes have implications on the means and rates that materials flow into the region, which, in turn, affect plant and animal life. Buck’s role will be to monitor the atmospheric deposition of trace elements like iron. Trace elements appear in the ocean in minute concentrations — parts per billion or even parts per trillion. However, they play a key role in the growth of phytoplankton — the tiny marine plants that form the very base of the marine food web and produce approximately half the oxygen in our atmosphere. In much of the world’s ocean, it is the presence or scarcity of iron that regulates the growth of phytoplankton.

Buck and his colleagues hope to develop a better understanding of how trace elements make their way from the upper atmosphere to the ice cap. They can arrive either as little particles, floating in the atmosphere and settling like dust, or they can fall as part of a raindrop or snowflake.

“In the Artic, the composition and abundance of aerosols tend to vary seasonally which is the reason it is important to get a series of observations over a long time scale to see how deposition rates of these aerosols change over the course of a year,” Buck said. “We care about that because in areas removed from river input and other continental influences, atmospheric deposition can be the primary source of trace elements like iron for the surface ocean.”

Buck and colleagues from Florida International University and Florida State University will use a technique utilizing a radioactive isotope of beryllium, itself a trace element, to measure the rate of atmospheric deposition. Beryllium-7 is created only in the upper atmosphere by the exposure of nitrogen and oxygen to cosmic rays, and has a half-life of 53 days. By measuring the concentration of beryllium-7 in samples, Buck will be able to estimate the rate beryllium and other trace elements are being deposited on the surface.

R/V Polarstern
Photo credit: Stephanie Arndt/Alfred Wegener Institute

The research team will take turns working on the ship in shifts of two months at a time. As many as 40 to 50 scientists might be on the R/V Polarstern during each shift, collecting samples and making a wide range of observations throughout the year. Buck is tentatively scheduled to be on board from mid-December 2019 through mid-February 2020.

“I really have no one to blame but myself for being assigned a winter shift,” Buck said. “It is very difficult to make these measurements during the winter, so it is very important to us to insure those winter samples are collected properly. When I said that out loud, they said ‘so I guess you want to go in the winter.’”

Although locked in the Arctic ice cap, the R/V Polarstern will not be stationary. The area where the researchers anticipate the ship will be frozen is subject to a surface current called the Transpolar Drift which propels sea ice from the East Siberian Sea to the Fram Strait, off the east coast of Greenland. The R/V Polarstern could drift as much as 1,500 miles during its year locked in the ice cap.

“The Arctic Ocean is a very interesting place with a lot of wind and a lot of physics going on up there,” Buck said. “You may not perceive the movement, but you will be moving.”

Buck’s participation in the MOSAiC project is funded by a four-year, $350,412 grant from the National Science Foundation Arctic System Science Program.

UGA Skidaway Institute scientists study dynamic Cape Hatteras waters

Sometimes called the “graveyard of the Atlantic” because of the large number of shipwrecks there, the waters off of Cape Hatteras on the North Carolina coast are some of the least understood on the U.S. eastern seaboard. University of Georgia Skidaway Institute of Oceanography scientist Dana Savidge is leading a team, which also includes UGA Skidaway Institute scientist Catherine Edwards, to investigate the dynamic forces that characterize those waters.

The four-year project, informally called PEACH: Processes driving Exchange at Cape Hatteras, is funded by $5 million grant from the National Science Foundation. Skidaway Institute will receive $1.2 million for its part.

Researchers Dana Savidge (left) and Catherine Edwards

Researchers Dana Savidge (left) and Catherine Edwards

Two opposing deep ocean currents collide at Cape Hatteras, making the Atlantic Ocean near there highly dynamic. The warm Gulf Stream hugs the edge of the continental shelf as it flows north from the tip of Florida.  At Cape Hatteras, it opposes a colder current, the Slope Sea Gyre current, that moves southward along the mid-Atlantic coast and breaks away from the coast toward northern Europe. As in the deep ocean, the cool shelf waters of the mid-Atlantic continental shelf meet the warm salty shelf waters from the south at Cape Hatteras.

The convergence of all of these currents at one place means that, after long lifetimes in the sunlit shallow shelves, these waters may export large quantities of organic carbon—small plants and animals that have grown up on the shelf—to the open ocean. Scientists have little understanding of the details of how that happens and how it is controlled by the high-energy winds, waves and interaction the between the constantly changing Gulf Stream and Slope Sea Gyre currents.

According to Savidge, the area is very difficult to observe because the water is shallow, the sea-state can be challenging and the convergence of strong currents at one place make it hard to capture features of interest.

“It’s difficult to get enough instruments in the water because conditions change rapidly over short distances, and it’s hard to keep them there because conditions are rough,” she said. “Ships work nicely for many of these measurements, but frequently, the ships get chased to shore because of bad weather.”

To overcome the limitations of ship-based work, the research team will use a combination of both shore- and ocean-based instruments to record the movement and characteristics of the streams of water. A system of high-frequency radar stations will monitor surface currents on the continental shelf all the way out to the shoreward edge of the Gulf Stream, providing real-time maps of surface currents.

“Measuring surface currents remotely with the radars is a real advantage here,” Savidge said. “They cover regions that are too shallow for mobile vehicles like ships to operate while providing detailed information over areas where circulation can change quite dramatically over short times and distances.”

Edwards will lead a robotic observational component in which pairs of autonomous underwater vehicles called gliders will patrol the shelf to the north and south of Cape Hatteras.  Packed with instruments to measure temperature, salinity, dissolved oxygen and bio-optical properties of the ocean, both shelf- and deep-water gliders fly untethered through the submarine environment, sending their data to shore at regular intervals via satellite.

To compensate for the notoriously difficult conditions, Edwards will take advantage of a novel glider navigation system she developed with students and collaborators at Georgia Tech that automatically adjusts the glider mission based on ocean forecasts as well as data collected in real time.

“Our experiments show that we can keep the gliders where they need to be to collect the data we need,” she said. “The best part is that we get to put the maps of surface currents together with the subsurface information from the gliders, and we can make all of this information available in real time to scientists, fishermen and the general public.”

The researchers will also place a number of moorings and upward-pointing echo sounders on the sea floor. These acoustic units will track the water movement while also recording temperature and density.  PEACH will focus primarily on the physics of the ocean, but the information the researchers gather will also help scientists more fully understand the chemistry and biology, and may cast light on issues like carbon cycling and global climate change.

“Everyone is interested in the global carbon budget, and the effect of the coastal seas on that budget is not well understood,” Savidge said. “For example, many scientists consider the continental shelf to be a sink for carbon, because there is a lot of biology going on and it draws in carbon.

“However, there are indications that the shelf south of Hatteras is both a sink and a source of carbon. This project may help clarify that picture.”

The project will run through March 2020. The remaining members of the research team are Harvey Seim and John Bane of the University of North Carolina; Ruoying He of North Carolina State University; and Robert Todd, Magdalena Andres and Glen Gawarkiewicz from Woods Hole Oceanographic Institute.

UGA Skidaway Institute scientists conduct winter 26-hour sampling program

On the weekend of January 24th, a team lead by UGA Skidaway Institute scientist Aron Stubbins conducted the latest “26 Hours on the Marsh” sampling program on the bluff at Groves Creek on the Skidaway Institute campus. The project was designed to investigate how salt marshes function and interact with their surrounding environment—specifically how bacteria consume and process carbon in the marsh. The team collected water samples throughout two complete tidal cycles, during both the day and night.

The outdoor laboratory on the bluff at Groves Creek.

The outdoor laboratory on the bluff at Groves Creek.

Skidaway Institute's Zac Tait, Thais Bittar, Rob Spencer (FSU) and Aron Stubbins prepare for a sample collection.

Skidaway Institute’s Zac Tait, Thais Bittar, Rob Spencer (FSU) and Aron Stubbins prepare for a sample collection.

Zac Tait collects a water sample from a skiff tied to the bank.

Zac Tait collects a water sample from a skiff tied to the bank.

Thais Bittar and Zac Tait begin to process the water sample.

Thais Bittar and Zac Tait begin to process the water sample.

About a dozen scientists and students were involved in the project. “26 Hours on the Marsh” is supported by two grants from the National Science Foundation. The grants total $1.7 million that represent larger, three-year, multi-institutional and multi-disciplinary research projects into salt marsh activity. These projects bring together faculty, students and staff from UGA’s Skidaway Institute, the University of Tennessee, Florida State University and Woods Hole Research Center. UGA Skidaway Institute scientists include principal investigator Jay Brandes; chemical oceanographers Aron Stubbins and Bill Savidge; physical oceanographers Dana Savidge, Catherine Edwards and Jack Blanton; and geologist Clark Alexander.