I am a Delta Science Fellow and a Postdoctoral Investigator at the University of California, Santa Cruz working with Dr. Raphael Kudela. My work investigates the physical, chemical, and biological factors that can promote development of harmful algal blooms (HABs) in Monterey Bay and the San Francisco Bay. A key aspect of this work is use of an Imaging FlowCytobot (IFCB), an in-situ automated submersible flow cytometer that generates high-resolution images of particles in-flow taken from the aquatic environment. The optical and image data are then transmitted to shore in real time, and a machine learning classifier is used to identify particles as different species of phytoplankton (much like facial recognition). This high-temporal resolution phytoplankton time-series is paired with targeted laboratory experiments to investigate drivers of bloom development under scenarios of short- and long-term change.
Another research area is dormancy cycling in resting cysts of Alexandrium catenella, a HAB dinoflagellate that causes paralytic shellfish poisoning (PSP). These cysts use environmental temperature to sync their dormancy-cycling to ensure that germination, and therefore bloom formation, only occurs during seasons that are favorable to the formation of large blooms. I am interested in understanding the plasticity of this species' temperature response to different annual temperature regimes (e.g. temperate, polar), including those due to climate change.
"Ready, Set, Bloom! Red Tides at Cape Cod National Seashore" (2016) 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.
Fischer, A.D., McGaraghan, A., Hayashi, K., Kudela, R.M. Unusual dinoflagellate dominance detected in northern Monterey Bay with automated imaging flow cytometery. In prep.
Fischer, A.D., Kulis, D.M., Brosnahan, M.L., and Anderson, D.M. Seasonal temperature dependence of the in situ emergence flux of Alexandrium catenella: A comparison with laboratory germination measurements. In prep.
Brosnahan, M.L., Ralston, D.K., Fischer, A.D., Solow, A.R., and Anderson, D.M., 2017: Bloom termination of the toxic dinoflagellate Alexandrium catenella: vertical migration behavior, sediment infiltration, and benthic cyst yield. Limnology & Oceanography, 62: 2829-2849.
Fischer, A.D. 2017. Alexandrium catenella cyst dynamics in a coastal embayment: temperature dependence of dormancy, germination, and bloom initiation. (Doctoral dissertation).
Fischer, A.D., Moberg, E.A., Alexander, H.A., Brownlee, E.F., Hunter-Cevera, K.R., Pitz, K.J., Rosengard, S.Z., and Sosik, H.M., 2014: Sixty Years of Sverdrup: A Retrospective of Progress in the Study of Phytoplankton Blooms. Oceanography, 27: 222-235.