Molecular insights into the niche of harmful brown tides
Wurch, Louie L.
MetadataShow full item record
Recurrent brown tide blooms caused by the harmful alga Aureococcus anophagefferens have decimated coastal ecosystems and shellfisheries along the Eastern U.S. and South Africa. The exact mechanisms controlling bloom formation, sustenance, and decline are unclear, however bottom-up factors such as nutrient type and supply are thought to be critical. Traditional assays for studying algal nutrient physiology require bulk community measurements or in situ nutrient perturbations. Although useful, these techniques lack the ability to target individual species in complex, mixed microbial assemblages. The motivation for this thesis is to examine the metabolic strategies utilized by A. anophagefferens for meeting its nitrogen (N) and phosphorus (P) demand at the cellular level using molecular tools that, even in the presence of complex microbial assemblages, can be used to track how nutrients influence the bloom dynamics of A. anophagefferens in the environment. Chapter two examines the global transcriptional responses of A. anophagefferens to N and P deficiency. Results demonstrate that A. anophagefferens has the capacity to utilize multiple forms of organic N and P when inorganic forms become unavailable. Chapter three analyzed the global protein changes in response to P deficiency and P re-supply. Consistent with transcript patterns, A. anophagefferens increases protein abundance for a number of genes involved in inorganic and organic P metabolism when inorganic P is deficient. Furthermore, increases in a sulfolipid biosynthesis protein combined with lipid data suggest A. anophagefferens can adjust its P requirement by switching from phospholipids to sulfolipids when inorganic P is unavailable. Analysis of protein abundances from P-deficient cells that were re-fed inorganic P demonstrates variations in the timing of turnover among various proteins upon release from phosphate deficiency. Chapter four tests the expression patterns of candidate gene markers of nutrient physiology under controlled culture experiments. Results show that expression patterns of a phosphate transporter and xanthine/uracil/vitamin C permease are indicators of P and N deficiency, respectively. Taken together, these findings provide insight into the fundamental and ecological niche space of this harmful algal species with respect to N and P and provide a platform for assaying nutrient controls on natural brown tide blooms.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2011
Showing items related by title, author, creator and subject.
Brown, Ellen Dunning (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1984-08)This thesis addresses several aspects of the problem of determining the effect of the low-frequency eddy variability on the mean circulation of the Western North Atlantic. A framework for this study is first established ...
Millard, Robert C.; Lake, B. J.; Brown, Neil L.; Toole, John M.; Schaaf, D.; Yang, K.; Yu, H.; Zhao, L. (Woods Hole Oceanographic Institution, 1990-12)A series of laboratory intercalibrations of a CTD system were undertaken between 1986 and 1990 as part of cooperative research program between the United States (US) and People's Republic of China (PRC). A comparison of ...
Brown, Neil L.; Frye, Daniel E.; Proakis, John (Woods Hole Oceanographic Institution, 1993-01)The feasibility of using inductive coupling with existing submarine telephone cables for telemetry of data from ocean sensors was investigated. The submarine telephone cable was simulated with a computer model and the ...