Research Projects    

1. Compilation of dissolved organic matter (DOM) data obtained from global ocean observations from 1994 to 2020

This compilation consists of measurements of dissolved organic matter (DOM) and other chemical and hydrographic parameters obtained during the global ocean observations from 1994-01-01 to 2019-12-31. Measurements of dissolved organic matter (DOM) in the open ocean have increased greatly since the late 1980's, spurred by the growth in scientific interest directed at the ocean carbon cycle. DOM data generated by many laboratories around the world are typically made available in diverse, regional data archives, making them less available than necessary for the data value to be maximized. The effort here was to make ship-collected bottle data accessible more directly and in uniform format. The emphasis was on spatial coverage of the global ocean, so the well-known and ongoing time-series data (such as the Bermuda Atlantic Time-series Study and Hawaiian Ocean Time-series) are not included; nor are coastal waters well represented in this first version. While the focus of this compilation is largely on dissolved organic carbon (DOC) and total dissolved nitrogen (TDN), we extended coverage to include the less frequently determined DOM isotopes (13C, 14C), select wavelengths and a single spectral slope of colored dissolved organic matter (CDOM), and DOM composition (i.e., dissolved combined neutral sugars). To the extent possible, the DOM data have been complemented with hydrographic data (e.g., temperature and salinity), other biogeochemical variables (e.g., oxygen, nutrients), the inorganic carbon system [e.g., dissolved inorganic carbon (with isotopes when available), pH, and total alkalinity], and anthropogenic (chlorofluorocarbons, sulfur hexafluoride, carbon tetrachloride) and natural tracers (neon, helium, tritium). A very few data are included for biological variables such as bacterial abundance and chlorophyll a concentrations. These data, from approximately 14000 stations (map below), are from taken from 230 cruises, providing 94324 measures of DOC (full water column where available) and 29113 measures of TDN (limited to the surface 250 m).

DOM Gompilation Hansell etal 2021

Data access:

NCEI data and metadata:

ODV collection:

ODV online analysis:

CITE AS: Hansell, Dennis A.; Carlson, Craig A.; Amon, Rainer M. W.; Álvarez-Salgado, X. Antón; Yamashita, Youhei; Romera-Castillo, Cristina; Bif, Mariana B. (2021). Compilation of dissolved organic matter (DOM) data obtained from the global ocean surveys from 1994 to 2020 (NCEI Accession 0227166). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. Accessed [date].

2. Dissolved Organic Matter (DOM) in the Arctic Ocean

This research depends on large research ice breakers as sampling platforms and we were involved in >10 major sampling campaigns in the past 10 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 measure in situ CDOM fluorescence and determine the bulk, optical, and molecular properties of DOM in discrete water samples. Together with the hydrographic measurements during those cruises we are able to develop a better understanding with respect to 3 major questions in the Arctic Ocean.

  • How useful is DOM as a hydrographic tracer and indicator for environmental change
  • What is the role of DOM for the carbon cycle in the Arctic Ocean
  • How important is DOM for the solubility and transport of trace elements in the Arctic Ocean

US National Science Foundation Logo

We are currently funded by the US National Science Foundation to continue our research addressing these questions.

Key collaborators:

  • University of South Carolina, USA
  • AWI, Germany
  • GEOMAR, Germany
  • University of Gothenburg, Sweden
  • NIOZ, Netherlands
  • Technical University of Denmark



Arctic Night

3. CIGOM: Consorcio de Investigacion del Golfo de Mexico – Hydrographic and biogeochemical aspects of the Natural and Anthropogenic Carbon Cycle in the Gulf of Mexico

The CIGOM project was funded by CONACYT and SENER, the Mexican Science Foundation and Ministry of Energy, respectively. It represents a multidisciplinary and international program involving 20+ Mexican Institutions along with collaborating institutions from France, Germany, Spain and the US. At the heart of the project lies the development of a profound understanding of the interactions of physical, biological, and chemical processes with large-scale oil spills in the Gulf of Mexico. The scope of the project includes observations from satellites, HF radar, moorings, AUVs’, and ships as well as modeling approaches. The Texas A&M group investigates biogeochemical aspects of the natural and anthropogenic carbon cycle by using a combination of classical water column sampling with new glider based sensors to investigate the distribution and relationship of hydrocarbons and the natural pools of organic and inorganic carbon in the open and coastal GoM.


Key collaborators:

  • CICESE - Center for Scientific Research and Higher Education at Ensenada, Mexico (lead institution)
  • Universidad Autonoma de Baja California, Ensenada, Mexico
  • Geochemical and Environmental Research Group (GERG), TAMU, USA

Yenisey Barochka


4. Carbon Fluxes and Transformations in Siberian Watersheds and Rivers

Since 2014 we are involved in the Russian research project “Sensitivity of carbon fluxes to climate variability in the land-atmosphere-hydrosphere system of the Yenisey River catchment”. This project focuses on a number of watersheds in the Central Siberian Plateau that are distinct in critical watershed characteristics. We are interested to identify the most important factors that control the lateral export of carbon species from the vast Siberian watersheds that contain significant amounts of organic matter relevant to global climate change feedbacks. I was involved in the original PARTNERS program that investigated 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 gradient in the Yenisey River drainage basin, Russia. This project is currently funded by the US National Science Foundation and the Russian Science Foundation.

Key collaborators:

  • Sukachev Institute of Forest (lead institution), Russia
  • Leibniz-Universitaet Hannover, Germany
  • Max Planck Institute for Biogeochemistry Jena, Germany


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5. Improve analytical sensitivity for biomarkers

Together with Dr. Karl Kaiser (lead PI) we were recently funded by NSF for the “Development of a high sensitivity, low sample volume method to quantify lignin phenols as geochemical and water mass tracer in the open ocean”. This project involves the modification of existing GC/MS methods to push the limits of sensitivity taking advantage of new technological developments in Mass Spectrometry as well as fundamental modifications to the sample preparation procedure. At the end of this project we plan a inter-laboratory comparison with colleagues involved in biomarker analysis of open ocean water samples. 

6. Contamination in Urban Watersheds of Houston

The urban streams in Houston have struggled with bacterial contamination for decades. In this project we use a combination of microbiology and biogeochemistry to investigate potential causes for the contamination. My lab uses a combination of elemental and isotopic analyses of organic matter and nitrate along with optical characterization of DOM to determine the potential sources of organic substrates that could sustain the observed contamination of Houston Bayous with fecal coliforms. This multiyear project was funded by the Texas Commission for Environmental Quality and is in its final stage of publishing the results of the study.

Glider 2

CTD Wave

Rainer at Pole