Dr. Andrew Juhl is a Doherty Associate Research Scientist in the Marine Biology Division. He earned his Ph.D. at the Scripps Institution of Oceanography, following an M.S. from Oregon State and a B.S. from University of Wisconsin-Madison.

His field of interest include: Plankton ecology, growth and physiology; zooplankton grazing; harmful algae blooms, especially dinoflagellates; physical/biological interactions; nutrient pollution of coastal waters, and sea-ice algae.

Here is his synopsis of his research efforts:

Phytoplankton, single-celled, planktonic algae, are the base of marine food webs. Nearly all other marine organisms are directly or indirectly dependent upon phytoplankton for nutrition. Although individually small, phytoplankton are so numerous in the ocean that their cycles of growth and decay influence global geochemical processes and the earth's climate. On local scales, excessive phytoplankton growth, or accumulations of certain phytoplankton species, can be harmful to other organisms, including humans. For these reasons, I am interested in how environmental factors influence phytoplankton growth and physiology, and the interactions between phytoplankton and other planktonic organisms. From a less utilitarian perspective, planktonic organisms are remarkable, and often beautiful creatures. Observing and studying them can be inspiring and amusing. Because plankton experience a world so different from our own, they provide us with fascinating examples of how unusual life forms can be. Nevertheless, they share many similarities with other creatures and thereby provide us with insight into the general rules of life.

I use a hypothesis-driven approach to address specific questions related to the more general topics listed above. I typically combine field sampling with controlled laboratory experiments and analyses.

Currently ongoing projects include: a study of phytoplankton nutrient limitation in Pensacola Bay (with M.C. Murrell of the US EPA Gulf Ecology Division); studies of predation-deterring substances produced by toxic dinoflagellates of the genus Alexandrium (with P. J. S. Franks of Scripps Institution of Oceanography and C. Martins of Woods Hole Oceanographic Institution); development of a PCR-based method to measure copepod grazing rates on specific phytoplankton prey species (with S. Dyhrman of Woods Hole Oceanographic Institution); and a study of the effect of shear forces on cellular integrity of the toxic dinoflagellate, Karenia brevis.

More information can be found on his web site: http://webcenter.ldeo.columbia.edu:81/people.nsf/0/c3aefa1d92baeb8185256ef30064906a?OpenDocument