2011-present Assistant Professor, Biology, Long Island University-Post (Brookville, NY)
2011-present Research Associate, Smithsonian Environmental Research Center (SERC) (Edgewater, MD)
2009-2011 Postdoctoral Fellow, Marine Science Network, Smithsonian Institution
2010-2011 Adjunct Faculty, Miami University (Miami, OH)
2010-2011 Managing Guest Editor, Biological Invasions Special Issue, Environmental Research
2009-2011 NSF Postdoctoral Scholar, Faculty Institutes for Reforming Science Teaching
2009 Instructor, Goucher College (Towson, MD)
2007-2009 Postdoctoral Fellow, Marine Invasions Lab, SERC
2007-2008 Guest Editor, Marine Bioinvasions Issue, ICES Journal for Marine Science
SELECT RESEARCH ACTIVITIES:
Figure 2. North Atlantic Littorina sp. snails.
RECENT RESEARCH ACTIVITIES:
WORK WITH INTERNS:
This past summer (2013), I had a summer intern, Zack Holmes, who helped me re-investigate research performed by my former advisor, Dr. Jeb Byers, myself, and colleagues (Byers et. al., 2008), on the common periwinkle snail (L. littorea’s) North American distribution and parasite ecology (10 years later) to explore temporal effects of trematode prevalence in snails and correlation with definitive host abundance. We traveled from Long Island to eastern Nova Scotia, collecting samples in the low and high intertidal zone from 25 different locations along the coast. We are currently analyzing the vast amount of data we collected during the summer related to the project.
Zack in the field collecting snails!
Last summer (2012), I supervised a summer intern on a project related to the effects of parasitism on behavior and physiology in the globally invasive European green crab (Carcinus maenas) on the east coast of the US (see pictures from that endeavor below). For this project, I collaborated with Dr. Blaine Griffen, University of South Carolina, on an NSF ROA award related to his NSF-funded project. In particular, this project explores the physiological and behavioral impacts of trematode parasitism on C. maenas. It involved experimental work to create infected and uninfected treatments of the crab along an infection gradient; we then video-taped for behavior, and finally dissected all crabs (n=70) for parasite infection intensity and physiological indices. The analyses of these data are ongoing, but with this important baseline data completed, we would like to later explore possible effects of both predation (e.g., shorebirds) and competition (specifically with Hemigrapsus sanguineus) on infected versus uninfected green crabs.
These are pictures from summer 2012 research at the Isles of Shoals, where I spent about 3 weeks doing research with colleagues on the European green crab (Carcinus maenas), pictured in flow through in the last picture!
WORK WITH GRADUATE STUDENTS:
With my graduate student, Leidy Leon, I am currently working on a new project related to L. saxatilis, involving locally-adapted phenotypes (‘ecotypes’) of the crab, which depend on the environment. These ecotypes are well-studied in Europe, but little is known about them in N. America. We are examining two ecotypes in particular (‘barnacle’ and ‘typical’) in populations from Nova Scotia to Long Island (encompassing a large portion of the species’ western Atlantic range), collecting morphological/phenotypic, life history (specifically reproduction), ecological, parasite, and genetic data for each ecotype. In a long-term laboratory experiment, I am also currently examining growth in each ecotype because the two ecotypes appear to demonstrate significantly different maximal and average sizes in natural populations.
Possible 'ecotypes' of L. saxatilis in eastern North America. The first is the barnacle ecotype, which is found associated with barnacles and is typically smaller and demonstrates characteristic patterning on its shell, and the second is the 'typical' ecotype which is generally larger, shows a wide variety of colors, and is associated with rocks, cobbles, and boulders in the upper intertidal zone.
OTHER SELECT RESEARCH ACTIVITIES:
I have been involved in several different projects related to marine parasites, aquatic invasions, benthic ecology, and population genetics, which are described below. These represent select descriptions of projects I have been involved with over the past several years.
Littorina saxatilis phylogeography:
I have studied the global distribution of the rough periwinkle, L. saxatilis, including native, introduced, and cryptogenic populations in North Atlantic, South Atlantic and Pacific regions. In particular, I am involved in three collaborative efforts exploring: A) North Atlantic phylogeography of L. saxatilis (Panova et al., 2011, PLOS One) and comparative phylogeography of congener, L. littorea, with colleagues in Sweden. B) The introduced population of L. saxatilis in San Francisco Bay on the Pacific coast to verify source, vector, and timing of introduction. C) a cryptogenic population in South Africa with colleagues at the University of Cape Town. The later two efforts are still in progress. In all of these populations, we have also collected data on parasitism to compare across regions (native, definitively introduced, and cryptogenic). See Figure 3 below.
Figure 3. This demonstrates the regions we have collected data for the global distribution of Littorina saxatilis.
Carcinus maenas population genetics:
In a project funded by the Census of Marine Life, I collaborated with colleagues on population genetics of the European green crab, Carcinus maenas, and the spread of new genotypes from Nova Scotia into the US. The manuscript for that project was published in PNAS. We have also investigated the recent introduction of the crab to Newfoundland and have used genetics, species demography, and coastal shipping records to help piece together the source, vector and timing of the introduction. Inference of source populations was possible due to an admixture zone in Nova Scotia comprised of southern and northern genotypes corresponding with the crab’s two historical introductions (Figure 4), which were also represented in Newfoundland. These data further highlight the importance of population genetics studies of invasive species as they can reveal likely sources of introduction, helping managers pinpoint populations on which to focus management efforts (Blakeslee et al. 2010, Diversity and Distributions).
Figure 4. This figure presents Northwest Atlantic and Newfoundland haplotype frequency diagrams (pie charts) for populations include in the Blakeslee et al. (2010) study. Our investigation demonstrates the division of the crab's introduced northwest Atlantic range into three areas dominated by different haplotypes: 1) eastern Nova Scotia, representing haplotypes (blue, white, black) from the crab's secondary cryptic introduction from northern Europe; 2) central/western Nova Scotian and Canadian Bay of Fundy, representing an admixture of haplotypes from both introduction events; 3) US populations, representing haplotypes (red, pink) from the original introduction from southern Europe to mid-Atlantic and southern New England in the US (From: Blakeslee et al. 2010).
FIGURE 5A FIGURE 5B
Figure 5a. This figure shows maps of sampling locations for two west coast invasive snails, Ilyanassa obsoleta (eastern mudsnail) and Littorina saxatilis (rough periwinkle), compared to their overlapping native range on the east coast of North America.
Figure 5b. The two snails show significantly different parasite richness and prevalence, which probably relates to their differing invasion histories and timing.