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The Role of Algicidal Bacteria and
Viruses in HAB Control
The raphidophytes are a common group of microalgae found in different
aquatic environments that can form "red tide" blooms. The "red tide"
blooms of raphidophytes have been densely documented worldwide in
recent years and have caused severe damage to fisheries. Although some
ecological studies demonstrated that some bacteria have a close
relationship with the raphidophytes blooms and they may play an
important role in naturally regulating the development and termination
of HABs, the mechanisms bacteria activate to produce algicidal and
growth-promoting components are largely unclear and understudied.
While interactions between bacteria and
raphidophytes have received little attention, our recent results
indicate that a bacterial isolate from the recent Bulls Bay Bloom has
the strong potential to stimulate raphidophyte growth
rate. We also have evidence of algicidal bacteria associated with
raphidophytes in SC stormwater detention ponds and in culture. We
are currently characterizing algicidal and algal
growth-promoting bacterial diversities and isolating
both kinds of bacteria from these environments.
In addition to algicidal and algal growth-promoting
bacteria, the SCAEL has recently begun research into the
realtionship between HABs and phycoviruses. There has been
a flurry of research on algal viruses in the last ten years, much
of that in the raphidophytes. In fact, one of the most well-known
algal viruses is HaV (Heterosigma akashiwo virus). We are
studying the relationship between phytoplankton and virioplankton
population dynamics in an effort to understand any possible role
viruses might play in HAB attenuation. In addition, we will be studying
viral dynamics in both a near-pristine estuarine reserve and eutrophic
stormwater detention ponds. This comparative study will allow us
to understand the effects of eutrophication (if any) on
virioplankton population dynamics.
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Algal Ecology Labs--331 Fort Johnson
Road--Charleston,
SC 29414.
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