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 Arctic rivers are the major way black carbon is transported to the ocean.

University of Georgia Skidaway Institute of Oceanography scientist Aron Stubbins led a team of researchers to determine the levels of black carbon in Arctic rivers and found that the input of black carbon to the Arctic Ocean is likely to increase with global warming. The results of their study were recently published in the journal Frontiers in Earth Science.

Black carbon, or biochar, is formed when vegetation and other organic matter burns. Today black carbon is a massive store of carbon in global soils, where it is thought to be very stable -- so stable, that researchers have previously suggested that adding black carbon to soils might be a good way to lock away carbon dioxide and reduce climate change. This new research reveals that the black carbon stored in Arctic soils is being exported to the oceans.

The Arctic is warming faster than other regions of the planet due to climate change. The scientists report that, as the planet warms, the amount of black carbon transported to the Arctic Ocean will likely increase. Once dissolved in the ocean and exposed to sunlight, black carbon may be rapidly converted back to the greenhouse gas carbon dioxide.

In ongoing work at UGA and partner universities, Stubbins and his colleagues are trying to determine just how much black carbon will be exported to the Arctic Ocean as the Arctic continues to warm, and once it reaches the oceans, what percentage will reach the atmosphere as carbon dioxide.

The article is titled “Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers.” In addition to Stubbins, the co-authors include Robert Spencer from Florida State University; Jutta Niggemann and Thorsten Dittmar from the University of Oldenburg, Germany; Paul Mann from Northumbria University; Max R. Holmes from Woods Hole Research Center; and James McClelland from University of Texas Marine Science Institute. 

The entire article can be viewed online at:

Stubbins has a website detailing this and other work on black carbon at:


Marine biogeochemist Julia Diaz has joined the faculty of the University of Georgia Skidaway Institute of Oceanography as an assistant professor.

Diaz graduated summa cum laude from the University of Georgia with a Bachelor of Science in biology and went on to earn her doctorate in earth and atmospheric sciences from Georgia Tech. She conducted postdoctoral research at Harvard University and the Woods Hole Oceanographic Institution. 

Diaz’s research examines how the chemistry and microbiology of the oceans shape each other and ultimately how this interaction affects ecosystem health from local to global scales.



  Photo credit: NOAA Okeanos Explorer Program, INDEX-SATAL 2010

Savannah, Ga. – University of Georgia Skidaway Institute of Oceanography scientist Aron Stubbins joined a team of researchers to determine how hydrothermal vents influence ocean carbon storage. The results of their study were recently published in the journal Nature Geoscience.

Hydrothermal vents are hotspots of activity on the otherwise dark, cold ocean floor. Since their discovery, scientists have been intrigued by these deep ocean ecosystems, studying their potential role in the evolution of life and their influence upon today’s ocean.

Stubbins and his colleagues were most interested in the way the vents’ extremely high temperatures and pressure affect dissolved organic carbon. Oceanic dissolved organic carbon is a massive carbon store that helps regulate the level of carbon dioxide in the atmosphere—and the global climate.

Originally, the researchers thought the vents might be a source of the dissolved organic carbon. However, their research showed just the opposite.

Lead scientist Jeffrey Hawkes, currently a post-doctoral fellow at Uppsala University in Sweden, directed an experiment in which the researchers heated water in a laboratory to 380 degrees Celsius, 716 degrees Fahrenheit, in a scientific pressure cooker to mimic the effect of ocean water passing through hydrothermal vents.

The results revealed that dissolved organic carbon is efficiently removed from ocean water when heated. The organic molecules are broken down and the carbon converted to carbon dioxide.

The entire ocean volume circulates through hydrothermal vents about every 40 million years. This is a very long time, much longer than the timeframes over which current climate change is occurring, Stubbins explained. It is also much longer than the average lifetime of dissolved organic molecules in the ocean, which generally circulate for thousands of years, not millions.

“However, there may be extreme survivor molecules that persist and store carbon in the oceans for millions of years,” Stubbins said. “Eventually, even these hardiest of survivor molecules will meet a fiery end as they circulate through vent systems.”

Hawkes conducted the work while at the Research Group for Marine Geochemistry, University of Oldenburg, Germany. The study’s co-authors also included Pamela Rossel and Thorsten Dittmar, University of Oldenburg; David Butterfield, University of Washington; Douglas Connelly and Eric Achterberg, University of Southampton, United Kingdom; Andrea Koschinsky, Jacobs University, Germany; Valerie Chavagnac, Université de Toulouse, France; and Christian Hansen and Wolfgang Bach, University of Bremen, Germany.

The study on “Efficient removal of recalcitrant deep-ocean dissolved organic matter during hydrothermal circulation” is available at


University of Georgia Skidaway Institute of Oceanography researcher Chris Marsay is on top of the world—literally.

Marsay arrived at the North Pole in early September. He is taking part in the US GEOTRACES Arctic Expedition on board the U.S. Coast Guard Cutter Healy, a polar icebreaker.

The project is part of an international, multiple icebreaker effort to conduct geochemical sampling of the Arctic Ocean. The cruise arrived at 90 degrees north on Sept. 5 in what is the first occupation of the North Pole by an unaccompanied U.S. surface ship—submarines usually follow ships below the ice. While at the pole, the Healy rendezvoused with the German ship conducting the German leg of the GEOTRACES Arctic program.

Marsay is working with UGA Skidaway Institute professor Cliff Buck and scientists from Florida State University and Rutgers University. The research team has been funded by the National Science Foundation to collect samples from the atmosphere, precipitation and surface water from melt ponds during the cruise.

“Our research goals are to describe the chemistry of atmospheric deposition to the region and quantify flux rates,” Buck said. “These data will then be shared with the scientific community to better understand biogeochemical cycling of trace elements and isotopes in the Arctic Ocean.”


Upcoming Event
Seminar: Sometimes it takes a hurricane: Establishment of a long-term monitoring network Currituck Sound, Albemarle-Pamlico Estuarine System, North Carolina
Dr. Heidi Wadman, U.S. Army Research Oceanographer
12/2/2015 2:00 pm
MCSRIC Conference Room

Great progress has been made towards understanding circulation dynamics in estuarine environments. However, research efforts in coastal lagoons, common features along the United States' East and Gulf coasts which represent ~13% of the world’s coastlines, have only recently seen similar success. Part of the challenge arises in that extensive, real-time monitoring of baseline conditions in many of these regions is lacking. The largest such system in the lower 48 states is the Albemarle-Pamlico Estuarine System (APES), located along the Outer Banks of North Carolina. The APES comprises over 4000 miles of ecologically diverse shoreline and is home to extensive economic activities. The passage through the estuary by Hurricane Irene in 2011 highlighted the lack of a cohesive monitoring network in the region. Subsequent attempts to hindcast the storm surge generated by the event met with limited success, largely due to a lack of during-storm measurements within, and detailed bathymetry of, the overall region. Although recent efforts have sought to establish a monitoring network in the greater APES region to establish baseline conditions from which to evaluate estuarine models and understand lagoonal response to storm events and climate change, current real-time measurements reflect short-term, discretely funded efforts at best. As a result, available environmental data are greatly limited both in the actual measurements being made as well as in the spatial distribution of short-lived monitoring stations. The U.S. Army Corps of Engineers is launching an extensive baseline monitoring network in the Currituck Sound, the northern-most member of APES, in the summer of 2015. Available data suggest that, despite assumptions that the shallow, wind-driven Currituck Sound should be very well-mixed, it also consistently represents the most eutrophic region of the greater APES, further highlighting the need for extensive measurements in this region. A system of five platforms will provide a complete cross-shore and alongshore profile of a variety of measurements in this shallow, wind-driven system, including winds, waves, currents, water level, salinity, turbidity, light attenuation, and seabed elevation. This presentation will provide a first look at the on-going installation of this network, as well as an opportunity to discuss potential expansion of the new network both in terms of measurements as well as locations outside of the Currituck’s boundaries. 


Harvey, E., S. Menden-Deuer, and T. A. Rynearson. 2015. Persistent intra-specific variation in genetic and behavioral traits in the raphidophyte, Heterosigma akashiwo. Frontiers in Microbiology 6:1277. doi: 10.3389/fmicb.2015.01277
Repeta, D. J., L. Aluwihare, C. Carlson, Z. Liu, C. Nelson, and A. Stubbins. 2015. Introduction to the special issue on the Biogeochemistry of Dissolved Organic Matter. Marine Chemistry 177, Part 2: 203-204. doi: 10.1016/j.marchem.2015.10.002
Wagner, S., R. Jaffe, K. Cawley, T. Dittmar, and A. Stubbins. 2015. Associations between the molecular and optical properties of dissolved organic matter in the Florida Everglades, a model coastal wetland system. Frontiers in Chemistry 3: 66. doi: 10.3389/fchem.2015.00066
Buck, C. S., C. R. Hammerschmidt, K. L. Bowman, G. A. Gill, and W. M. Landing. 2015. Flux of total mercury and methylmercury to the northern Gulf of Mexico from U. S. estuaries. Environmental Science & Technology (pagination pending). doi: 10.1021/acs.est.5b03538
Logvinova, C. L., K. E. Frey, P. J. Mann, A. Stubbins, and R. G. M. Spencer. 2015. Assessing the potential impacts of declining arctic sea ice cover on the photochemical degradation of dissolved organic matter in the Chukchi and Beaufort seas. Journal of Geophysical Research: Biogeosciences (pagination pending) doi: 10.1002/2015jg003052/full
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