Tag Archives: marine chemistry

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.

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Molecular-level relationships key to deciphering ocean carbon

by Alan Flurry

From beach shallows to the ocean depths, vast numbers of chemical compounds work together to reduce and store atmospheric carbon in the world’s oceans.

In the past, studying the connections between ocean-borne compounds and microbes has been impractical because of the sheer complexity of each. Three University of Georgia faculty members—along with an international team of scientists—bring to the forefront technological developments that are providing scientists with the analytical tools needed to understand these molecular-level relationships.

Their perspective article appears March 7 in the Proceedings of the National Academy of Sciences. It focuses on dissolved organic matter, or DOM, in the world’s oceans as a central carbon reservoir in the current and future global carbon cycle.

“Dissolved organic carbon is an amazing and confounding molecular soup,” said Aron Stubbins, co-author and associate professor of marine sciences at UGA housed at the Skidaway Institute of Oceanography in Savannah. “It sits at the center of the ocean carbon cycle, directing the energy flow from the tiny plants of the sea, phytoplankton, to ocean bacteria. Though around a quarter of all the sunlight trapped by plants each year passes through dissolved organic carbon, we know very little about the chemistry of the molecules or the biology of the bacterial players involved.”

The carbon the microbes process is stored in seawater in the form of tens of thousands of different dissolved organic compounds.

Researchers thought they had a handle on how some aspects of the process works, but “a number of new studies have now fundamentally changed our understanding of the ocean carbon cycle,” said the paper’s lead author Mary Ann Moran, Distinguished Research Professor at UGA.

In the context of methodological and technological innovations, the researchers examine several questions that illustrate how new tools—particularly innovations in analytical chemistry, microbiology and informatics—are transforming the field.

From how different major elements have cycles linked though marine dissolved organic matter to how and why refractory organic matter persists for thousands of years in the deep ocean to the number of metabolic pathways necessary for microbial transformation, the article infers a scale of enhanced and expanded understanding of complex processes that was previously impractical.

The perspective article, “Deciphering Ocean Carbon in a Changing World,” was shaped in discussions at a 2014 workshop supported by the Gordon and Betty Moore Foundation and Microsoft Research Corporation. Moran’s research has been supported by the Gordon and Betty Moore Foundation’s Marine Microbiology Initiative.

Co-authors on the paper include UGA’s Patricia Medeiros, assistant professor in the department of marine sciences. Others involved are with the Woods Hole Oceanographic Institute; the Scripps Institute of Oceanography and the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego; University of Tennessee, Knoxville; Oregon State University; Columbia University; The Pacific Northwest National Laboratory, Richland Washington; the University of Washington; University of Oldenburg, Germany; Sorbonne Universités; and the University of Chicago.