CONTACT: GARY GALLUZZO
300 Plaza Centre One
Iowa City IA 52242
(319) 384-0009; fax (319) 384-0024
Release: Aug. 28, 2002
Biologist Conducts Research On Origins Of 'Red Tide'
A University of Iowa researcher is studying a phenomenon that may help scientists
to better understand the cause of the ecologically and financially costly
"red tide" that periodically kills millions of fish along the U.S.
Atlantic and Gulf coasts.
Debashish Bhattacharya, assistant professor of biological sciences in the
University of Iowa College of Liberal Arts and Sciences, whose work is published
in the Aug. 9 issue of the journal Proceedings of the National Academy of
Sciences, says his goal is to explain the origin of the cell component called
a "plastid," responsible for photosynthesis in marine algae.
"The dinoflagellates, or marine plankton, are one of the most economically
important single-celled organisms because of the toxic red tides that they
cause resulting in fish and shellfish mortality. Our work lays the foundation
for understanding the basic biology of these species," he says.
Red tide is a natural phenomenon that results from massive blooms of tiny,
single-celled algae called Karenia brevis, usually found in warm salt water.
Bhattacharya notes that algae, as primary producers in the food chain, are
critical to maintaining life on Earth, and the plastid, in turn, is the cell
organelle responsible for algae photosynthesis. As a result, the question
of plastid origin is an important problem in evolutionary biology, Bhattacharya's
primary field of research.
"We show in this paper that the dinoflagellate plastid originates from
a so-called tertiary endosymbiosis in which the dinoflagellate 'host' cell
has stolen its photosynthetic ability from another algal group, the haptophytes,"
he says. "My lab is interested in how endosymbiosis has driven the origin
and diversification of the huge diversity of photosynthetic eukaryotes (single-celled
organisms) on our planet. We believe that endosymbiosis is one of the most
important evolutionary forces in the history of the Earth."
Bhattacharya says that his laboratory has the best phylogenetic resources
to unravel the evolutionary history of these algae. He adds that his group
recently was awarded a $790,000 grant from the National Science Foundation
and the U.S. Department of Agriculture to generate a genomic database for
the toxic dinoflagelate Alexandrium tamarense. He says the database will be
valuable to a large number of scientists working on the evolution and basic
biology of various algae.