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I am a PhD candidate studying Biological Oceanography in the MIT-WHOI Joint Program

 
 

I am a PhD candidate in the MIT-WHOI Joint Program working with Dr. Don Anderson. I am interested in phytoplankton physiological ecology, phenology, and biological sensors, and in particular in predicting how harmful algal blooms will respond to a changing climate. 

As the sectors of water, food, and energy become increasingly linked in the coastal zone, the challenge of managing change becomes daunting. The pace of change in estuarine–coastal ecosystems will likely accelerate as the human population and economies continue to grow and as global climate change accelerates. Only with a continuing flow of information from observations can we measure, understand, and anticipate future changes along the world’s coastlines, and ultimately improve stewardship of the resources upon which we depend. 


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. 


Media

"Ready, Set, Bloom! Red Tides at Cape Cod National Seashore" is one of the 12-part webisode series Outside Science (inside parks) which focuses on science in the National Parks. In collaboration with Colorado State University, the National Park Service releases a new episode each month in 2016 that highlights the many ways young people are getting involved. 

Filmed and edited by Weston Dockter.


Publications

Fischer, A.D., Brosnahan, M., Anderson, D.M. Quantifying the chilling requirement for germinability of natural Alexandrium fundyense resting cysts (submitted)

Fischer, A.D., Moberg, E.A., Alexander, H.A., Brownlee, E.F., Hunter-Cevera, K.R., Pitz, K.J., Rosengard, S.Z., Sosik, H.M. (2014). Sixty Years of Sverdrup: A Retrospective of Progress in the Study of Phytoplankton Blooms. Oceanography, 27: 222-235.


 

Contact

afischer@whoi.edu