New Study Uncovers Key Role of Bacteria in the Formation of 'Red Tide' Algal
Blooms
Implications for Climate Modeling
November 16, 2009

Red tide.
High resolution
<http://www.noaanews.noaa.gov/stories2008/images/redtide.jpg>  (credit: NOAA
)
According to a new study <http://www.pnas.org/content/106/40/17071.abstract>
published in Proceedings of the National Academy of Sciences, NOAA and
NOAA-funded university scientists are closer to understanding why "red
tides," called harmful algal blooms form. These toxic harmful algal blooms
threaten marine ecosystems, human health, and cost local and regional
economies millions of dollars annually through fishery closures, recreation
and tourism losses.

The study looked at the impact that the cooperative interactions between
marine microalgae and bacteria have on the growth of harmful algal blooms

Scientists have long recognized that certain species of bacteria are closely
associated with the microalgae that form the harmful algal blooms, but
didn't understand why the blooms formed or what role the bacteria play.
The researchers found that certain species of bacteria form a
mutually-beneficial relationship with the algae that promotes the growth of
each. The bacteria release a chemical which helps the algae absorb iron, a
critical nutrient for photosynthesis. The algae, in turn, release organic
compounds to support the growth of the bacteria.
The potential impacts of the study are extensive, and could result in
improved modeling and forecasting of harmful algal blooms to potential
strategies for prevention, according to William Sunda, Ph.D., of NOAA's
Beaufort Laboratory <http://www.ccfhr.noaa.gov/about/beaufort.html> , a
co-author of the report.
 "The results of the research have global implications," said Sunda. "If we
can find a way to inhibit the bacteria we should be able to help communities
around the world deal with problematic and costly algal blooms."
The study also offers new insight for climate change models, since
dimethylsulfide, a gas produced by the bloom-forming algae, plays a critical
role in the process of cloud formation and the ability of clouds to reflect
sunlight back into space. The degree to which light is reflected in turn
influences solar heating of the Earth, affecting global climate.