Fifth Annual Long Island Natural History Conference






















Plankton blooms, decreasing temperatures and recent fishkills:
is there a connection? 

Sixto Portilla, The Graduate Center, CUNY

A series of recent publications by the speaker record the effect of some nutritional characteristics of marine plankton on the mortality of one local marine ectotherm, the hard clam, Mercenaria mercenaria, resulting from decreasing temperature. They describe the regulation of cell membrane viscosity in ectothermic organisms in response to decreasing temperature.  More importantly, these works articulate the role of two dietary omega-3 fatty acids, EPA and DHA, abundant yet variable in our local phytoplankton, in facilitating successful acclimation of marine planktivores, like Atlantic menhaden, to decreasing temperature.  The speaker has compiled records of plummeting atmospheric temperature, water temperature and the ephemeral presence of blooming phytoplankton to assemble a theory of the primary cause of recent, nuisance fishkills in New York waters and throughout New England.

Sixto Portilla began his graduate studies in 1996 in water resources; earning a Master of Science degree in Environmental Engineering from Manhattan College.  He began studying estuarine ecology in 2007, and shortly afterwards, in 2008, began his doctoral work at the City University of New York.  It is from his work on “the influence of diet on hard clam acclimation to decreasing temperature” that his topic for today’s discussion is derived.