Gulf of Mexico Research Initiative (GoMRI), “Role of microbial exopolymers in aggregation and degradation of oil and dispersants”, Santschi, P.H. (Deputy Director and PI), with Quigg, A. (Consortium Director), and Knapp, T., Wade, T.L., Chin, W.-C., Passow, U., Hatcher, P.G., Silvan, J., and Finkel, Z. (co-PIs), Jan. 1, 2015 – Dec. 31, 2017 ($7,245,432 total, $3,209,495 to TAMUG).

Vision and Mission: The explosion of the Deepwater Horizon (DwH) drilling rig in the northern Gulf of Mexico on April 20, 2010 released ~ 4.1 million barrels of oil over 84 days with an estimated 60% of this reaching the sea surface. While it is known that weathering and hydrodynamic forces affect both the distribution and properties of the oil released, and that opportunistic microbes play an important role in its degradation, there are few studies examining the interactions between oil, microbes (phytoplankton, bacteria) and their exudates. This proposal brings together a group uniquely qualified to study the molecular-level chemistry of sparingly-soluble substances in complex systems and the associated microbial communities.

The Vision of the Consortium is to understand how the presence of hydrocarbons trigger production of exopolymeric substances (EPS) that may protect organisms from the oil, emulsify the oil, or both, therefore altering its degradation. The interaction among EPS, oils and the local environmental factors plays a critical role in determining the fate of oil (e.g., degradation, dispersion or sedimentation) from oil spills. The Mission of this proposal is to develop a process-based understanding of the role that EPS, micro-gels, and transparent exopolymer particles (TEP) play in the fate of oil (e.g., degradation, dispersion or sedimentation) and, in addition, how the dispersant Corexit affects these processes.

Our approach: By examining the microbial response to oil-contamination at three levels:
(Tier 1) small (0.01-1 L) scale laboratory experiments (microchip and batch cultures) on bacterial and phytoplankton isolates to test the impact of oil and/or Corexit in concert with multiple stressors on growth rate and EPS production; (Tier 2) medium sized (6 L) roller table experiments with cultured isolates as well as native microbial populations (from field collected samples) to study the interaction of EPS produced by different oil degrading bacterial and phytoplankton with oil and/or Corexit under a few selected conditions (following findings in Tier1); and (Tier 3) large (100 L) mesocosm experiments to study the interactions between natural microbial communities, EPS and oil/and or Corexit. Naturally produced particles from the Gulf of Mexico will be collected to seed experiments in Tier 2 and 3.

Research Themes: The objective of the Consortium is to establish a mechanistic understanding for the interactions among oil and the dispersant (Corexit), and EPS, micro-gels, and TEP under various environmental conditions. The expected outcomes correspond to GRI Theme 2 (70%) Chemical evolution and biological degradation of the petroleum/dispersant system and GRI Theme 3 (30%) Environmental effects of the petroleum/dispersant system on the water column in coastal waters and organisms, in order to address the science of ecosystem recovery.

Objectives: This project aims to test the following central hypothesis and sub-hypotheses:
Microbes (bacteria, phytoplankton) respond to oil and dispersant (Corexit), by producing exopolymeric substances which interact with minerals, organic particles and organisms, and therewith determine the fate, distribution and potential effects of these hydrocarbon pollutants.
(H1): In response to oil and/or Corexit, the microbial community modifies its output of EPS, which critically determines the fate of oil and Corexit in terms of dispersion, aggregation, chemical bonding, and degradation.
(H2): The physicochemical characteristics of EPS (e.g. portion and type of charged functional groups, amphiphilicity, relative hydrophobicity) depend on the strain/species of microbes, the type of disturbance (e.g. oil, Corexit, or both), and the environmental conditions.
(H3): The physicochemical characteristics of different types of EPS and its aggregates, including micro-gels, nano-gels or TEP, determine the role of aggregation vs. dispersion potential of a particle assemblage, and thus the fate of particles and oil/ dispersant.

Integration of Consortium Activities: The proposed consortium activities are tightly integrated in sequences of experimental tiers, with the findings in each tier constraining activities at the next tier level. Small scale lab microchip and batch culture experiments will allow us to test a large number of concentrations and factors driving the oil-microbe interactions, which then determine which combinations are used at the roller table and mesocosm tiers. In turn, the interpretation of complex interactions at the higher tiers (mesocosms) will be guided by the outcomes of the simpler microchip/batch culture and roller table experiments. The outreach coordinator and data manager will participate at each step both by conducting science and in their respective tasks.

Scientific and Societal Impact: This Consortium aims to investigate the relationship between oil/dispersant (Corexit) fate and the marine microbial community under various environmental conditions. Our research program plans to show that the marine microbial community actively responds to oil/dispersant challenges by regulating its EPS release accordingly, and that the EPS released interacts with the oil/dispersant. These results will enhance the fundamental understanding of the how marine microbes (both phytoplankton and bacteria) and their exudates physically determine the fate and transport of oil and dispersants in the ocean. Although a variety of environmental factors and microbial contribution have been demonstrated to influence oil/dispersant fate and transport, the relationship whereby these contributing factors influence each other are not well known. The most important and unique impact of the proposed research is to establish the interactive mechanisms of oil/dispersants, marine microbes, EPS and various environmental factors that could critically determine the fate of oil pollutants and the associated ecological impact. This information can serve as the basis to establish improved predictive models for the risk assessment, to develop potential interventions to reduce the environmental impact and to formulate better responding/management plans for future oil spill incidents.

Consortium Members: The consortium is led by Texas A&M University and comprises 5 other collaborating institutions and Texas Sea Grant. Texas A&M University, including researchers from Marine Biology, Marine Science, Oceanography, and the Geochemical and Environmental Research Group, will be responsible for the overall project management and lead the laboratory experiments and field collections. Collaborating institutions supporting the microbe and exudate analysis include the University of California - Merced for the bacterial microfluidic chips, micro-gel aggregation, microscopy study and minority educational outreach, the University of Southern California to examine the prokaryotic microbial (bacteria and archaea) community structure and activity, Mount Allison University (Canada) to examine phytoplankton community structure and activity, the University of California Santa Barbara to investigate the role of microbial EPS production for aggregation/ degradation/ dispersion of oil/ dispersant using roller table experiments and Old Dominion University to analyze the exudates with multiple state-of-the-art instrumentation. Texas Sea Grant will provide their support for outreach activities through its well-established state-wide and national networks. Materials developed from this project will be disseminated with their extensive extension network. Consortium members have extensive experience working in the northern Gulf of Mexico and are uniquely qualified to study the molecular-level chemistry of sparingly-soluble substances in complex systems. While the work will be focused on examining biological and chemical phenomena, we will include physical dynamics in order to better understand the multi-factorial consequences of the spill on the system by using data from the TABS buoy network. Individual consortium members have collaborated with each other in different projects previously but this will be an exciting opportunity to bring our collective expertise together for this unique interdisciplinary project.

Publications:

Quigg, A., Passow, U., Chin, W.-C., Bretherton, L., Kamalanathan, M., Xu, C., Schwehr, K.A., Zhang, S., Sun, L., Wade, T.L., Finkel, Z.V., Doyle, S., Sylvan, J.B., Williams, A.K., Obeid, W., Hatcher, P.G., Knap, A.H., Santschi, P.H. 2016. Chemical and microbial Controls of Aggregation and Degradation of Oil and Dispersants by Microbial Exopolymers., L&O Letters, 1, 2016, 3–26.

Published Abstracts:

  • Passow U.; Sweet J., Schwehr K.A.; Xu C.; Zhang, S.; Lin Y.; Santschi P.H.; Quigg A. 2016. Oil, Diatom Exudation and Marine Oil Snow. The Gulf of Mexico Oil Spill and Ecosystem Science Conference, Tampa, FL, Feb. 1-4, 2016.
  • Santschi, P.H., Chin, W.-C., Chiu, J., Doyle, S., Finkel, Z., Gold, G., Hatcher, P.G., Irwin, I., Knap, T., Li, X.-X., Lin, Y.M., Obeid, W., Passow, U., Quigg, A., Schwehr, K.A., Shi, D., Sylvan, J., Wade, T., Xu, C., Zhang, S. 2016. Role of microbial exopolymers in aggregation of Oil and dispersants. The Gulf of Mexico Oil Spill and Ecosystem Science Conference, Tampa, FL, Feb. 1-4, 2016.
  • Santschi, P.H., Xu, C., Kaplan, D., Yeager, C., Zhang, S., Schwehr, K.A. 2016. Unexpected behaviour of radionuclides associated with natural organic matter in the environment. International Goldschmidt Conference in Yokohama, Japan, June 26 - July 1, 2016.
  • Xu, C., Zhang, S., Sugiyama, Y., Ohte, N., Ho, Y.-F., Fujitake, N., Kaplan, D.I., Yeager, C.M., Schwehr, K.A., Santschi, P.H. 2016. Role of natural organic matter on iodine and Pu distribution and mobility in environmental samples from the northwestern Fukushima Prefecture. International Goldschmidt Conference in Yokohama, Japan, June 26 - July 1, 2016.
  • Santschi, P.H., Xu, C., Zhang, S., Schwehr, K.A., Kaplan, D.I., and Yeager, C.M. 2016. Detection and assessment of specific natural organic compounds as carriers for radionuclides (e.g., I, Pu) in soil and water environments at ambient concentrations. International Committee for Radionuclide Metrology – Low Level Radioactivity Measurements Techniques (ICRM-LLRMT) conference, Seattle (WA, USA) September 26-30, 2016.
  • Morales-McDevitt, M.E., Wade, T.L., Knap, A., Gold-Bouchot, G., Shi, D., Sweet, S.T., Santschi, P.H., Quigg, A.. 2016. Degradation of WAF, CEWAF, and DCEWAF in biologically enriched mesocosms. Texas Bays and Estuaries Conference, University of Texas Marine Science Institute Education Center, 855 E. Cotter Street, Port Aransas, TX 78373.
  • Xu, C., Zhang, S., Beaver, M., Lin, Y., Lin, P., Sun, L., Schwehr, K.A., Wade, T.L., Kopp, K., Quigg, A., Passow, U., Chin, W.-C., Chiu, M.-H., Hatcher, P.G., Knap, A.H., Santschi, P.H. 2016. Microbially-mediated exopolymeric substances (EPS) production, composition and their role in regulating Macondo oil transport in a coastal phytoplankton-seeded mesocosm experiment. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium on “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 10-13, 2016.
  • Saijin Zhang 1ǂ, Chen Xu 1ǂ, Morgan Beaver1, Peng Lin1, Luni Sun1, Kathleen A. Schwehr1, Terry L. Wade3, Kendra Kopp1, Antonietta Quigg2,3, Uta Passow4, Wei-Chun Chin5, Patrick G. Hatcher6, Anthony H. Knap3, Peter H. Santschi, P.H. 2016. Effects of Water-Accommodated Fraction (WAF) of Macondo Oil and Corexit on Formation of Marine Snow and Their Fate in Mesocosm Experiments. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium on “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 10-13, 2016.
  • Sun, L., Xu, C., Zhang, S., Lin, P., Schwehr, K.A., Quigg, A., Chiu, M.-H., Chin, W.-C., Santschi, P.H. 2016. Light-induced aggregation of bacterial exopolymeric substances. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium on “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 10-13, 2016.
  • Chiu, M.-H, Khan, Z., Garcia, S. G., Drobenaire, H. W., Santschi, P.H., Quigg, A., Chin, W-C. 2016. Effect of Engineered Nanoparticles on Marine Phytoplankton Exopolymeric Substances Release. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Kamalanathan, M., Schwehr, K.A., Bretherton, L., Genzer, J., Hillhouse, J., Simmons, J., Santschi, P.H., Quigg, A. 2016. Prediction of marine aggregate’s exposure to chemically enhanced (COREXIT) water accommodated fraction of oil using Fourier Transform Infrared (FTIR) spectroscopy. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Bretherton, L., Genzer, J., Hillhouse, J., Santschi, P.H., Quigg, A. 2016. Multi-parameter assessment of fast repetition rate (FRR) fluorescence signals in natural phytoplankton communities exposed to surrogate Macando Oil and the dispersant Corexit using during the DwH oil spill. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Hatcher, P.G., Obeid, W., Wozniak, A.S., Xu, C., Zhang, S., Santschi, P.H., Quigg, A. 2016. Identifying oil/marine snow associations in mesocosm simulations of the Deep Water Horizon Oil Spill event using solid-state 13C NMR spectroscopy. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Wade, T.L., Knap, A., Morales-McDevitt, M.E., Gold-Bouchot, G., Shi, D., Sweet, S.T., Quigg, A., Santschi, P.H. 2016. Preparation of Water Accommodated Fraction (WAF) and Chemical Enhanced Water Accommodated Fraction (CWAF) for Dosing of ADDOMEx Mesocosms Experiments. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”,, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Beaver, M., Xu, C., Zhang, S., Lin, P., Schwehr, K.A., Wade, T.L., Quigg, A., Santschi, P.H. 2016. Production and composition of exopolymeric substances (EPS) in the presence of water accommodated fraction (WAF) and Corexit in two contrasting environments: open ocean versus coastal ocean. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”,, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Agueda,, O., Beaver, M., Xu, C., Zhang, S., Lin, P., Schwehr, K.A., Wade, T.L., Quigg, A., Santschi, P.H., Sylvan, J., Passow, U., Chin, W.-C., Hatcher. P.G. 2016. Relationships between surface tension and chemical composition of exopolymeric substances (EPS) in the presence of water accommodated fraction (WAF) and Corexit in two contrasting environments: open ocean versus coastal ocean. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”,, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Lin, P., Xu, C., Zhang, S., Sun, L., Schwehr, K.A., Bretherton, L., Quigg, A., Santschi, P.H. 2016.  Partitioning of natural radionuclide analogues for particle cycling in the ocean (234Th, 233Pa, 210Pb, 210Po and 7Be) with biopolymers associated with coccolithophores, one of the dominant phytoplankton species in the Gulf of Mexico: A case study with Emiliania huxleyi.  72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”,, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Beaver, M., Xu, C., Zhang, S., Lin, P., Schwehr, K.A., Wade, T.L., Quigg, A., Santschi, P.H. 2016. Production and composition of exopolymeric substances (EPS) in the presence of water accommodated fraction (WAF) oil and Corexit in two contrasting environments: Open ocean versus coastal ocean. 72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium “Chemical and Biological Processes Regulating Transport of Pollutants in the Gulf of Mexico and Its Estuaries”,, Galveston, TX, November 2016.72nd Annual Southwest Regional Meeting (SWRM), ACS Symposium, Galveston, TX, November 2016.
  • Morales-McDevitt, M.E., Wade, T.L. Knap, A.H., Gold-Bouchot, G., Shi, D., Sweet, S.T., Santschi, P.H., Quigg, A. 2017. Water Accommodated Fraction (WAF) and Chemical Enhanced Water Accommodated Fraction (CWAF) production using BP surrogate oil and COREXIT 9500 for Dosing of ADDOMEX  Mesocosms: Experiment 1. Gulf of Mexico Oil Spill and Ecosystem Science Conference 2017, New Orleans, LA. February 6-9, 2017.
  • Gold-Bouchot, G., Shi, D., Sweet, S.T., Morales-McDevitt, M.E., Ramirez-Miss, N., Passow, U., Quigg, A., Santschi, P.H., Knap, T.H., and Wade, T.L. 2017. Analysis of Hydrocarbons in WAF and CWAF by Fluorescence. Results of an intercalibration exercise. Gulf of Mexico Oil Spill and Ecosystem Science Conference 2017, New Orleans, LA. February 6-9, 2017.
  • Chiu, M.-H., Chin, W.-C., Santschi, P.H., Doyle, S., Finkel, Z., Gold, G., Hatcher, P.G., Irwin, I., Knap, T., Li, X.-X., Lin, Y.M., Obeid, W., Passow, U., Quigg, A., Schwehr, K.A., Shi, D., Sylvan, J., Wade, T., Xu, C., Zhang, S. 2017. Impact of Oil Spill and Corexit on Marine Microgel Formation. Gulf of Mexico Oil Spill and Ecosystem Science Conference 2017, New Orleans, LA. February 6-9, 2017.
  • Santschi, P.H., Chin, W.-C., Chiu, J., Doyle, S., Finkel, Z., Gold, G., Hatcher, P.G., Irwin, I., Knap, T.H., Li, X.-X., Lin, Y.M., Obeid, W., Passow, U., Quigg, A., Schwehr, K.A., Shi, D., Sylvan, J., Wade, T.L., Xu, C., Zhang, S. 2017. Role of Microbial Exopolymers in Aggregation of Oil and Dispersants. Gulf of Mexico Oil Spill and Ecosystem Science Conference 2017, New Orleans, LA. February 6-9, 2017.
  • Xu, C., Zhang, S., Beaver, M., Lin, P., Sun, L., Schwehr, K.A., Quigg, A., Hatcher, P.G., Wozniak, A., Santschi, P.H. 2017. Microbially-mediated exopolymeric substances production, composition and regulation of Macondo oil transport in two contrasting environments. Gulf of Mexico Oil Spill and Ecosystem Science Conference 2017, New Orleans, LA. February 6-9, 2017.>
Dr. Peter H.Santschi

Dr. Peter H.Santschi
Professor
Department of Marine Sciences
1001 Texas Clipper Rd
Bld# 3029, Office 346
Galveston, TX, 77554 USA

E-mail: santschi@tamug.edu
Phone: (409) 740-4476
Fax: (409) 740-4786