Dr. Kevin Strychar

I. Coral bleaching has become a major problem for coral reefs on a global basis. Coral bleaching is the process by which the endosymbiotic dinoflagellate alga called Symbiodinium (a zooxanthella) and/or photosynthetic pigments residing within the host and/or symbiont are reduced within the coral tissue, exposing the white skeleton beneath. The symptoms of bleaching (turning pale white in coloration), however, is not confined to corals and has been observed in many other benthic invertebrates including sea anemones, zoanthids, tridacnid (giant) clams, sponges, and foraminifera. It is a sign of stress, and, if severe, can result in death, sometimes on a massive scale. Studies indicate numerous causes of bleaching are involved including disease, elevated oxygen, increased and decreased salinity, and elevated temperature. Historically, elevated temperature appears to be the only factor that can be correlated with global bleaching of corals.

Current student projects include: (1) examining disease mechanisms that may induce bleaching in corals; (2) describing patterns of scleractinian, alcyonacean, and gorgonian corals bleaching in the Gulf of Mexico ; (3) characterizing near-shore coral patches as fishery habitat; and (4) assessing microbial assemblages commonly associated with shallow-water corals.

II. The health of coral reefs has been seriously declining since the 1970's. A decrease in coral abundance, by as much as 95% in some areas, has been associated with coral disease. One of the first diseases with a confirmed pathogen, white pox disease (WPD), was reported to affect corals off Key West , Florida , and is now considered a common threat to Caribbean corals, particularly the elkhorn coral, Acropora palmata. As many as 54 pathogens have been reported as ‘agents' in the coral marine environments, with yellow band (YB) disease affecting the coral Montastrea annularis , dark spot syndrome (DSS) affecting S iderastrea siderea and Stephanocoenia michelinii , and white-band disease (WBD) causing Acropora mortality in Florida, the Bahamas, and the Caribbean, and their incidence appears to be increasing. I t is believed that many benthic invertebrates respond to stress utilizing phagocytic-like cells called amoebocytes. In order to characterize how recognition occurs, it is necessary to describe the mechanisms of positively identifying “self” vs. “other” within corals.

Current projects are examining how coral cells identify and characterize normal vs. injured cells in scleractinian and gorgonian corals.

Globally, five major taxonomic groups of deep-water corals (DWCs) have been identified (Cimberg et al. 1981), including: Alcyonacea (soft corals), Gorgonacea (sea fans, bamboo corals, and tree corals), Scleractinia (cup corals, stony corals, or true corals), Stylasterina (hydrocorals), and Antipatharia (black corals), many which appear to be concentrated in the northern latitudes. Along the eastern coast of North America , 35 species of DWCs are believed to exist.

Current student projects include: (1) molecular analyses of deep-water coral that exist as “forests/thickets” to determine if cryptic taxa exist. Further, a comparative data set of Paragorgia and Primnoa from different localities and depth ranges are being established; (2) bioluminescence of deep-water corals is currently being examined; (3) compounds isolated from ocean invertebrates are structurally unique often showing pronounced activities. Currently we are examining metabolites from deep-water coral organisms to determine if any chemicals are used to deter predation and/or to attract prey.

In most coastal marine environments, phytoplankton plays a major role in primary production. Understanding the patterns and processes of biodiversity in relation to primary production is fundamentally important for sustainable management of ecosystems, like Laguna Madre (LM) and the Coastal Bend Estuary (CBE) , located in the Gulf of Mexico (GOM) . Coastal areas like LM and the CBE are of great economic and ecological importance. Laguna Madre, for example, is considered one of the most productive bay systems in Texas , producing more fish than Galveston Bay ( DeYoe 2003 ). Coastal areas like CBE , however, are rapidly degrading due to increasing human pressures, such as pollution, and changing land and sea use. In late 1989 a brown tide bloom made history by thriving from 1989 -1997 to what is believed to be one of the longest continual algal blooms in history ( DeYoe 2003 ).

As human populations continue to grow, increased anthropogenic loading from various sources (agricultural waste, fertilizers, sewage, etc.) exacerbate eutrophication of coastal waters. Pollution of estuaries is known to cause harmful algal blooms (HABs). These toxic species often cause extensive die-offs of fin- and shellfish, sea grasses, and other plankton. Less known are the physiological processes that decrease HAB growth and reproduction; some hypotheses indicate lysis due to viral pathogens. An alternative possibility is that mortality is caused by factors internal to the cells. Such information is vital for improving the management of estuaries and developing strategies to protect and restore its living marine resources.

Current projects include: (1) characterization of environmental factors (e.g. nitrate, phosphate, etc.) that promote growth and reproduction of phytoplankton; and (2) metabolism of bloom-forming algae in estuarine environments.