Grantee Research Project Results

A Molecular Approach to Understand Harmful Algal Blooms

EPA Grant Number: F07E20885
Title: A Molecular Approach to Understand Harmful Algal Blooms
Investigators: Wurch, Louie L.
Institution: Massachusetts Institute of Technology
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2007 through August 1, 2010
RFA: STAR Graduate Fellowships (2007) RFA Text |  Recipients Lists
Research Category: Academic Fellowships

Objective:

Harmful Algal Blooms (HABs), and their relationship to societal activities (i.e. eutrophication) are a controversial and hot topic in oceanography. HABs can affect the ecosystem in a variety of ways such as through the release of toxins (some species), the creation of hypoxic or anoxic zones, or by shading benthic sea grass communities. HABs present a global problem because of their widespread effects on public health, the coastal environment, and the economy. Understanding HAB nutrient physiology is necessary for understanding bloom formation and bloom dynamics. Applying unique molecular tools to this system has the potential to greatly increase our knowledge of nutrient physiology in HABs. I am interested in using a quantitative molecular approach on a model HAB species to help answer a number of questions such as: Which nutrient species are important in stimulating and terminating blooms? To what degree is the physiology of the cells linked to nutrient concentrations in the water? How does the nutritional physiology of a single HAB species in a mixed community change over an entire bloom event? What are the anthropogenic links (if any) to bloom formation?

Approach:

Aureococcus anophagefferens, the species responsible for “brown tide” events, provides an excellent model for studying HABs. The ability to easily culture this organism in the lab, combined with the upcoming release of its genome, makes this species an ideal candidate for study. By using a global gene expression method I can identify genes and pathways involved in nutrient metabolism and stress. The method proposed here is SAGE (Serial Analyses of Gene Expression), which makes it possible to evaluate the simultaneous expression patterns of thousands of genes quantitatively over a range of conditions. Annotation of the genes can be accomplished by mapping to the genome. A species-specific quantitative RT-PCR assay will be developed to examine the expression patterns of key genes (identified through SAGE) from field populations over an entire bloom event.

Expected Results:

With the upcoming release of a fully sequenced genome, we have an unprecedented opportunity to discover how a HAB organism responds to nutrient loading and the cellular mechanisms underlying those responses. This project will provide key regulation data to help identify transcripts involved in nutrient metabolism and stress responses. The discovery of nutrient regulated transcripts, and their putative function, will provide novel targets for tracking the nutritional physiology of field populations. Using a quantitative molecular approach will allow us to track the in situ nutritional status of an individual HAB species in a mixed community over entire seasons. This will provide enormous insight in determining the links among eutrophication, HABs, and societal activities as well as increase our ability to better predict when blooms will occur.

Supplemental Keywords:

Harmful algal blooms, eutrophication, brown tide, SAGE, transcriptome profiling, gene expression, algal physiology,

Progress and Final Reports:

2008

2009

Final