Chemical Signaling by Marine Plants
On land, plants, herbivores, and predators use chemicals released by plants to obtain information about that plant and its interactions with its environment. For example, some plants can detect chemicals in the air that have been released by other plants that are being eaten. The detection of these compounds causes the receiving plant to upregulate genes that lead to or increase the production of chemical defenses against the herbivores that are consuming their neighbor. Some plants can also release airborne chemicals that signal predators or parasitoids of the herbivores that are consuming them. These chemicals are known as “infochemicals” because they convey information to the plants and animals that are able to detect them.
The importance of infochemicals in the marine environment is less well known and is mostly limited to chemicals that are transmitted directly between organisms or are carried by water. However, many intertidal plants produce small volatile compounds that are released into the air at low tide and may be capable of conveying information to other plants and algae, herbivores, and predators of the herbivores. My lab is currently studying the production and release on one of these compounds, a small sulfur-containing molecule called dimethyl sulfide (DMS). We are conducting studies to determine when DMS is released, how much is produced, and its effects on other intertidal plants and animals.
Harmful Algal Blooms
"Green tides" are excessive growths of green algae that are occuring more frequently throughout the world and in Puget Sound. These seaweed blooms cause a variety of environmental problems by overgrowing other marine plants and reducing oxygen supplies. They also produce noxious odors when they accumulate on beaches. In collaboration with researchers at Seattle Pacific University, my lab has been studying the occurence of algae that form green tides and has been looking at factors that promote algal growth. We have also been studying the biology and ecology of the algae that produce green tides, with an emphasis on the production of natural products by the algae.
Seaweed Chemical Ecology
An important focus of research conducted by my lab is the productive of biologically active compounds by seaweeds. Current studies focus on the production and use of several classes of bioactive metabolites that include catecholamines, reactive oxygen species (ROS), phlorotannins, and sulfur metabolites. Our research addresses questions regarding why seaweeds produce these chemicals, the effects of environmental factors on the amounts that are produced, the release of these chemicals into the environment, and the effects of these chemicals on other plants and animals.
Chemical Ecology of DMS(P) in Seaweeds and Symbionts
Dimethylsulfoniopropionate (DMSP) and its breakdown products dimethyl sulfide (DMS), acrylic acid, and acrylate are produced by many seaweeds and by the algal symbionts of many marine animals. Dr. Van Alstyne's lab has been studying the production of these compounds in seaweeds and in the microalgal symbionts of anemones and corals. Many of these studies focus on the functions of the compounds, which include osmotic acclimation and protection from herbivory and oxidative stresses, the use of these compounds as signaling molecules, and the release of these compounds into the environment.