Research Overview I work primarily in marine systems to experimentally examine general ecological concepts, often in an applied context. Three themes that run through my research are: (1) the paramount role of foundation species in community structure and function, (2) the influence of environmental stress on community interactions, and (3) oceanographic features as large-scale drivers of community pattern. My work consists primarily of field surveys and manipulative experiments, often coupled with laboratory experiments in which I have developed an ecophysiology perspective. Throughout my research, I have actively sought opportunities to mentor and collaborate with undergraduates. Summarized below are three lines of my current research:

Hypoxia
Hypoxia is a threat to marine systems worldwide on par with over-fishing, yet there is little known about the impacts of hypoxia aside from widely recognized mass-mortality events and dead zones. I have focused on the implications of mortality events across levels of ecological organization from the individual to ecosystem. I have also explored the sublethal effects of hypoxia on community dynamics, which often occur in a predictable way. The implication of my research is that the full impact of hypoxia has been largely underestimated.

Cobble Beaches
Beds of the cordgrass Spartina alterniflora can ameliorate solar stress and substrate
instability on cobble beaches of New England, and allow marine organisms to establish that would otherwise be excluded from the mid-intertidal. Within that community established by the primary foundation species Spartina, other interactions also play a role. An example of this hierarchical organization is the secondary facilitation of marine invertebrates by the ribbed mussel Geukensia demissa, a foundation species that is itself dependent on Spartina. Interestingly, an invasive species also benefits from this hierarchical facilitation.

Galapagos urchins
The slate-pencil urchin Eucidaris galapagensis is an abundant member of the subtidal rock wall community of the Galapagos Marine Reserve. A diverse assemblage of encrusting organisms (e.g. corals, bryozoans, ascidians) inhabits the urchin spines. Dozens of species can be found on a single urchin. The urchins clearly play an important role in the provision of substrate, and I currently have experiments underway to examine if the urchins provide a refuge from predation for the organisms encrusting their spines.

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