Dr. Liz Perotti is a post-doctoral researcher in Dr. Michael Hadfield's lab here at Kewalo. Her work focuses on the mechanisms by which larvae of marine invertebrates recruit to their adult habitats to further understand the basis of community structure and ecology.
Dr. Perotti's research career in ecology began while she was an undergraduate at Boston University, and the molecular biology training she received while working in cancer research at Massachusetts General Hospital after graduation provided her with the tools necessary for addressing ecological and evolutionary questions at a molecular level.
While a graduate student at the University of California at Berkeley, Dr. Perotti became interested in questions about how geology and geologic history affect the ecology and evolution of marine communities.
"Working in the San Francisco Bay area was the ideal environment for my research as it is a geologically active and complex region", says Dr. Perotti. "It allowed me to study how hard substrates, like the rocks upon which intertidal organisms live, their attributes, and distribution in space and time affect the ecology of those communities."
Benthic invertebrates must contend with a variety of biotic (e.g., temperature, salinity) and abiotic (e.g., predation, competition) factors that affect their recruitment to suitable habitats, survival through adulthood, and evolution.
"Each species in these communities has its own evolutionary history and has arrived on the evolutionary scene at different times. Organisms bring unique suites of traits that were shaped by past environments to the ecological table," Dr. Perotti points out.
By understanding the relative importance of different environmental factors to these species and communities as a whole, underlying mechanisms that shape community ecology and the scales on which they operate can be identified.
"This is especially important for predicting the impacts of climate change and habitat alteration on benthic communities," notes Dr. Perotti.
Many marine communities are structured by "supply-side" processes such as recruitment of larvae to the adult habitat. The hydrodynamic environment can affect transport and behavior of marine invertebrate larvae on their voyage to and from adult habitats. The effects of hydrodynamics can be disparate for larvae that differ in size and utilize different mechanisms for swimming.
Dr. Perotti's research compares larval transport and behavior of various species of fouling organisms in different hydrodynamic regimes by filming larvae with fouling communities in flumes. One species Dr. Perotti uses in her work is Hydroides elegans, a tubeworm with planktotrophic larvae (free-swimming larvae that feed in the plankton) that use cilia to swim. Hydroides larvae appear to be affected differently by the hydrodynamic environment than species with larger larvae that use muscles for movement such as the barnacle, Balanus amphitrite.
Dr. Perotti points out that current work using fouling communities without ambient flow suggests that some organisms in fouling communities, namely solitary tunicates and sabellid worms can have large effects on the hydrodynamic environment that larvae encounter by pumping water compared to other members of the community.
Dr. Perotti is also evaluating how these larvae behave in a more dynamic environment that presents typical conditions that larvae encounter as measured in the field.
Dr. Perotti's research also addresses the question of the molecular basis of reception of environmental cues during settlement by larvae. Larvae of many types of benthic marine animals are induced to settle and metamorphose by chemical cues from conspecific organisms, prey, or biofilms on the substratum.
"Some larvae are able to detect water-borne cues whereas others need to come in direct contact with the inducer," notes Dr. Perotti.
Organisms like Hydroides elegans, the dominant fouling tubeworm found in warm water ports around the world, prefer a biofilmed surface.
"There is still a lot to be learned about how marine larvae detect cues from the environment and the molecular basis of reception." Dr. Perotti and colleagues are currently screening for genes used by H. elegans larvae that are metamorphically competent and ready to settle onto a hard substratum.
Dr. Perotti received her Ph.D. from the University of California at Berkeley and is currently a post-doctoral research fellow in Dr. Michael Hadfieldʻs Lab.
Video showing a fouling community in still seawater with cyprid larvae (Balanus amphitrite) and particles. (Video by Liz Perotti).