About My Science

         My research focuses on the role of marine microbial communities on the biogeochemical fluxes through planktonic food webs. In particular, I am interested in understanding and predicting the effects that the anthropogenic changes in matter inputs into the ocean exert on the microbial heterotrophic and autotrophic metabolisms. To this aim, I have been using a variety of experimental approaches (e.g. enzymatic techniques, lab simulated nutrient inputs) and modeling work.

    During my PhD work, I found that microbial communities responses to matter inputs are complex, being dependent on the magnitude and nature of the inputs and, probably on the type of food web affected by the inputs. Although patterns of response were found, the magnitude and direction of these changes and the associated carbon fluxes are unknown. Furthermore, interesting responses registered (e.g. unexpected phytoplankton mixotrophic responses after organic inputs) may play an important role in the microbial responses to matter inputs, and require further study.

        My current projects are focused on the study of carbon cycling at Station ALOHA. I am devoted to the study of bacterial and community respiration in epipelagic and mesopelagic waters. Additionally, I am interested in factors controlling heterotrophic bacteria functioning at Station ALOHA and the bioavailability of autochthonous dissolved organic matter.  My future research will investigate the genomic and transcriptomic responses of bacteria to organic and inorganic matter inputs and the role of community composition in these responses. We hypothesized that metabolic cascades and community succession patterns that regulate the turnover of naturally occurring DOM will be related to the initial heterotrophic bacteria populations and the ambient nutrient concentrations which will determine the extent to which DOM is utilized.


Contact information:
Sandra Martinez-Garcia
Department of Oceanography
University of Hawaii
1950 East-West road
Honolulu, HI, 96822