Research Projects

Organic matter transport and transformations in large Arctic Rivers

We are interested in the chemical composition, processing and transport of organic matter in large Arctic rivers to better understand the link between the organic matter trapped in permafrost and peat soils and the river channels. We combine microbiological studies with the chemical analysis of bulk, isotopic, and molecular level analyses of organic matter. Our group was involved in the original PARTNERS program to study the discharge of dissolved organic matter by the six largest Arctic rivers. We are now working with collaborators in Russia and Germany to do a more detailed study along an upstream-downstream transect in the Yenisey River, Russia.

Key collaborators:

Dr. Anatoly Prokushkin, V.N. Sukachev Institute of Forest SB RAS, Akademgorodok, Krasnoyarsk, Russia
Dr. Georg Guggenberger, Institut fuer Bodenkunde, Leibniz-Universitaet Hannover, Hannover, Germany
Dr. Karl Kaiser, TAMUG
Dr. Patrick Louchouarn, TAMUG

Relevant publications:

Amon RMW, A.J. Rinehart, S. Duan, P. Louchouarn, P. Raymond, R.M. Holmes, J.W. McClelland, BJ Peterson, G. Guggenberger, A. Prokushkin, C. Stedmon, S.A.Walker. (2012). Dissolved organic matter sources in large Arctic rivers. GCA 94: 217-237: doi: 10.1016/j.gca.2012.07.015

Prokushkin, A.S., O.S. Pokrovsky, L.S. Shirokova, M.A. Korets, J. Viers, S.G. Prokushkin, R.M.W. Amon, G. Guggenberger and W.H. McDowell (2011). Sources and the flux pattern of dissolved carbon in rivers of the Yenisey basin draining the Central Siberian Plateau. Environ. Res. Lett. 6 (2011) 045212 (14pp) doi:10.1088/1748-9326/6/4/045212.

Dissolved organic matter in the Arctic Ocean - Biogeochemical and Physical Controls

This research depends on large research ice breakers as sampling platform and we were involved in 6 major sampling campaigns in the past 8 years. Through our international collaborations we were able to cover the Eurasian Basin using Swedish, German, and Russian ships as well as the Canada Basin using Swedish, US, and Canadian ice breakers. During those expeditions we measured in situ CDOM fluorescence and analyzed discrete water samples for bulk, optical, and molecular properties of DOM. Together with the hydrographic measurements during those cruises we are able to develop a better understanding of DOM biogeochemistry and surface ventilation processes in a rapidly changing Arctic Ocean.

Another aspect of this project are specific laboratory experiments to investigate the role of sea ice dynamics for the distribution of dissolved solids in the Arctic Ocean and how that might change with increasing summertime losses of sea ice.

Key collaborators:
Marcel Babin, De´partement de Biologie and Que´bec-Oce´an, Universite´ Laval, G1V 0A6, Canada
Dorothea Bauch, Leibniz Institute of Marine Sciences, University of Kiel, Germany
Ron Benner, Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, 29208, USA
Bob Newton, Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, New York, USA
Bert Rudels, Finnish Institute of Marine Research, P.O. Box 2, 00561 Helsinki, Finland
Ursula Schauer, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
Colin Stedmon, National Institute for Aquatic Research, Technical University of Denmark, Charlottenlund, Denmark
Jim Swift, Scripps Institution of Oceanography, La Jolla, CA, USA

Relevant publications:

Fichot, C. G., K. Kaiser, S. B. Hooker, R. M. W. Amon, M. Babin, S. Bélanger, S. A. Walker, and Ronald Benner (2013). Pan-Arctic distributions of continental runoff in the Arctic Ocean. Sci. Rep. Scientific Reports 3, Article number: 1053 doi:10.1038/srep01053

Granskog, M. A., C. A. Stedmon, P. A. Dodd, R. M. W. Amon, A. K. Pavlov, L. de Steur, and E. Hansen (2012), Characteristics of colored dissolved organic matter (CDOM) in the Arctic outflow in the Fram Strait: Assessing the changes and fate of terrigenous CDOM in the Arctic Ocean, J. Geophys. Res., 117, C12021, doi:10.1029/2012JC008075

Stedmon C.A, R.M.W. Amon, A.J. *Rhinehart, S.A. *Walker (2011). The supply and characteristics of colored dissolved organic matter (CDOM) in the Arctic Ocean. (2011). Marine Chemistry 124: 108–118

*Walker, S. A., R. M. W. Amon, et al. (2009). "The use of PARAFAC modeling to trace terrestrial dissolved organic matter and fingerprint water masses in coastal Canadian Arctic surface waters." J. Geophys. Res. 114: doi:10.1029/2009jg000990.

Amon, R.M.W, G. Budeus &  B. Meon. 2003. Dissolved organic carbon (DOC) distribution and origin in the Nordic Seas: Exchanges with the Arctic Ocean and the North Atlantic. J. Geophys. Res.-Oceans: Vol. 108, No. C7,3221,doi:10.1029/2002JC001594.

Potential substrate sources for E. coli in the urban watershed of Houston

We use a combination of elemental and isotopic analyses of organic matter and nitrate to determine the potential sources of organic substrates that could sustain the observed contamination of Houston Bayous with fecal coliforms. The chemical composition of organic matter is related to optical properties of the bayou water in order to investigate the potential for using optical in situ sensors to trace the sources leading to the contamination.

Key collaborators:

Dr. Robin Brinkmeyer, TAMUG

Combining in situ sensors and a Slocum glider for studying the interaction of biogeochemical and physical-mixing processes in the Gulf of Mexico.

This is a new and exciting analytical window for TAMUG to do large spatial scale investigations in the Gulf of Mexico and other ocean basins. At the moment the glider is equipped with sensors for conductivity, temperature, pressure, dissolved oxygen, Chlorophyll fluorescence, turbidity, CDOM fluorescence, and micro turbulence. We are also working on the development of new sensors more specific for our applications.

Key collaborators:

Dr. Ayal Anis, TAMUG