RESEARCH

The phenology of phytoplankton biomass – timing of bloom onset, peak concentration, and termination of bloom duration – is often coupled to seasonality. As a consequence of a specific geographic location, seasonal changes can induce cold-, heat-, and light- stress during a species’ annual life cycle. Therefore, many phytoplankton species have evolved specific behavioral and life cycle strategies for surviving periods of seasonally-induced stress so that they can exploit favorable periods of the year for growth and reproduction.

One such strategy is the resting cyst stage of many dinoflagellates, some of which are important harmful algal bloom (HAB) species. Cysts can survive extended periods of unfavorable environmental conditions, enabling them to germinate into pelagic swimming cells once conditions become favorable. I focus on the cysts of Alexandrium, whose toxic blooms are a serious economic and public health concern throughout the world. Blooms of Alexandrium are highly seasonal, due in part to life cycle alterations between motile, vegetative cells and resting cysts, which overwinter in bottom sediments. 

Alexandrium fundyense cysts

Alexandrium fundyense cysts

My research strives to quantify how Alexandrium cysts use seasonal environmental cues to coordinate germination for when conditions are conducive for growth in a shallow temperate estuary. I use both laboratory and field approaches to identify and model the biological and physical mechanisms regulating bloom initiation in the Nauset Marsh system on Cape Cod, MA.

This research is part of an interdisciplinary project to investigate issues of human health as it pertains to oceanographic research under the Woods Hole Center for Oceans and Human Health (WHCOHH).

Schematic of the internal and environmental factors regulating cyst germination. 

Schematic of the internal and environmental factors regulating cyst germination.