The Evolutionary Secrets of Desert Cells
An MBL ecologist explores green algaes ability to survive and thrive in the desert
February 20, 2008
It turns out the desert isnt nearly as devoid of life as it looks. In an article published in the February 2008 issue of BioScience, MBL Ecosystems Center senior scientist Zoe Cardon provides an overview of the remarkable diversity of green algae living in desert crusts, where they and numerous other microbes help prevent wind and water erosion, control water runoff, keep the soil fertile, and sequester and process nitrogen.
This green algal underground, say Cardon and co-authors Louise Lewis and Dennis Gray, also offers important insights into the survival secrets of green plants. The authors cite genetic evidence that single-celled desert green algae were once aquatic. And though they still resemble the green algae commonly found in ponds, desert green algae have been evolving over millions of years to survive the extreme pressures of desert life.
According to Cardon and her co-authors, ongoing studies of aquatic taxa that have diversified to the desert habitat could provide interesting information about photoprotection under environmental stress and protection against the effects of extreme dehydration, a threat to all known forms of life.
Green algae are very closely related to the larger green plants we are all used to seeing around us on land. Very few of those larger plants are able to survive being dried out in deserts, or even in gardens when we forget to water, but these tiny, simple green algal cells can be dried out and wetted up and still survive. Learning about how they tolerate harsh desert conditions may provide clues to how and why more familiar larger green plants evolved to tolerate (or not tolerate) desiccation, says Cardon.
The study of microbiotic desert crusts is of increasing importance to managers of western arid and semi-arid land who are working to preserve these hard-working-yet-fragile ecosystems.
A new arrival at the MBL Ecosystems Center, Cardon is a nationally recognized terrestrial ecologist with expertise in plant physiological ecology and plant-rhizosphere interactions. She will collaborate with scientists in the MBLs Bay Paul Center for Comparative Molecular Biology and Evolution in the micro-eco interface, an initiative that bridges two of the largest MBL research centers and leverages their combined strengths in ecosystems science and molecular analysis.
Cardon is a former associate professor in the Department of Ecology and Evolution at the University of Connecticut and was associate director of the Universitys Center for Integrative GeoSciences. She holds a Ph.D. from Stanford University and undergraduate degrees in biology and Spanish from Utah State University.
The MBL is a leading international, independent, nonprofit institution dedicated to discovery and to improving the human condition through creative research and education in the biological, biomedical and environmental sciences. Founded in 1888 as the Marine Biological Laboratory, the MBL is the oldest private marine laboratory in the Western Hemisphere. For more information, visit www.MBL.edu