Algae play key roles in the global carbon cycle, helping trap carbon emissions. But some algal species can bloom, discoloring coastal waters and reduce the amount of light and oxygen available in the ecosystem. To describe these events, the term “harmful algal blooms” (HABs) was introduced two decades ago to note that accumulation of algal biomass can sometimes disrupt an ecosystem.
|Aerial view of Great South Bay, NY during a brown tide bloom in June 2008. (Image from the Suffolk County Department of Health Services)
In a study published online February 23 in Proceedings of the National Academy of Sciences, a team of researchers, including DOE JGI scientists led by Igor Grigoriev reported the first complete and annotated genome sequence of a HAB species that causes brown tide: the marine phytoplankton Aureococcus anophagefferens.
The 56-million base pair genome was sequenced by the DOE JGI from a culture isolated sample collected from the shores of Long Island, NY, one of the areas most affected by the microalga when it first appeared 25 years ago on the east coast of the United States.
The genome sequence offers scientists a “parts list” with clues to Aureococcus‘ ability to survive in varying marine environments, and outgrow many of its competitors. “Compared to the phytoplankton inhabiting the same estuaries,” said Grigoriev, “Aureococcus, which outcompetes them, shows genome-encoded advantages to benefit from alternative nutrients, survive under variable light conditions, and encode the largest number of selenoproteins (which use the trace element selenium to perform essential cell functions) known to date.”
Watch a slideshow about the research narrated by DOE JGI collaborator and study first author Chris Gobler from Stonybrook University.