Anthropogenic changes to nutrient cycling have dramatically altered ecosystems across the globe, particularly in coastal estuaries such as Narragansett Bay, RI where nitrogen (N) limits primary production. Atmospheric deposition of N into the Bay (through precipitation, direct diffusion, and the settling of particulates) remains poorly quantified, and recent work has found a relationship between precipitation amount and hypoxic events that implies N cycling in the Bay is not fully understood.

To better understand the biological implications of this uncertain flux, I first analyzed high time resolution buoy data collected by the Narragansett Bay Commission and precipitation records to identify multi-day correlations between precipitation events and chlorophyll abundance. I then sampled macroalgae (Ulva spp.) in the Providence River and northern Narragansett Bay at ~48 hour time resolution to investigate if the d15N and C:N ratio of macroalgae changes in response to precipitation.

Finally, I am collaborating on a project to quantify the flux of gaseous NH3 and particulate NH4+ between Narragansett Bay and the atmosphere through the use of acid-coated filters and a Relaxed Eddy Accumulation system.

Gaps in the canopies of tropical rainforests present interesting ecological dynamics by altering light levels, soil humidity, and a number of other biotic and abiotic factors. These temporary gaps, often created by disturbances such as storms, contribute to the heterogeneity of tropical rainforests, and understanding nutrient cycling in these gaps is crucial to understanding the biogeochemical dynamics of a forest as a whole.

My project, advised by Dr. Stephen Porder, is part of a larger manipulated field experiment being conducted by IBES PhD. candidate Lindsay McCulloch. I will examine mycorrhizal fungi (a symbiont of most vascular plant species that exchanges soil nutrients for plant-produced carbon) under different light and soil-nutrient conditions. Light may be a limiting factor in this exchange, as light limits how much carbon a plant can fix through photosynthesis and invest in nutrient-acquiring symbioses.

Understanding if, how, and to what degree light affects this relationship may have implications for our understanding of the carbon and phosphorus cycles in tropical canopy gaps, and observing if/how this relationship interacts with other symbioses, such as symbiotic nitrogen fixation, could enhance our understanding of nutrient cycling more generally.

Humans have unintentionally facilitated a number of species becoming established outside of their native ranges, a phenomenon termed “unmanaged relocation.” Although typically viewed as a negative anthropogenic impact, this unmanaged relocation could prove vital to species’ ability to shift their ranges in response to climate change. To assess the importance of the relationship between unmanaged relocation and climate, Morgan is collecting dendrochronological data and building climate niche models for a sample group of ten species of trees that are native to the southeastern United States but have naturalized populations north of their native range.

Maya is researching how damselfish, a family of territorial fish that cultivate algal gardens, impact primary productivity in the Galapagos Marine Reserve. These territories are algal oases in a community characterized by high grazing pressure and support a suite of higher trophic levels. Her study has demonstrated niche differentiation across damselfish species through resource partitioning, highlighting the importance of a diverse guild of damselfishes for ecosystem functioning in the Galapagos Archipelago. 

Due to various anthropogenic factors including shoreline hardening and coastal development, the diamondback terrapin (Malaclemys terrapin) is known to have declined throughout its range, but questions remain as to how diamondback terrapin populations interact across geographic distances and perceived barriers such as urban areas and roads under current levels of habitat fragmentation.  Moreover, our knowledge of populations within individual geographic sites is limited due to terrapins’ idiosyncratic life history, as male terrapins do not leave the marsh to nest and must therefore be sampled in the water via trapping, which provides imperfect snapshots of population composition.  With the help of the Kartzinel Lab, the Rhode Island Department of Environmental Management, The Wetlands Institute, and several other collaborators, I am attempting to address these gaps in our knowledge by conducting two genetic analyses: an analysis of genetic relatedness among terrapin populations from locations in MA, RI, CT, NY, and NJ, and an indirect quantification of male biodiversity in a putatively stable NJ population.  Both parts of this study are unique in that they utilize novel molecular tools which have not yet been applied to diamondback terrapin population genetics and may prove to be broadly applicable across the range of this ecologically important species.  The analysis of relatedness will employ restriction site-associated DNA sequencing (RADseq), sampling thousands of loci across the terrapin genome to obtain a robust understanding of variation among and between populations, while the paternity analysis will attempt to quantify the number of unique male genotypes within a population by comparing maternal DNA and offspring DNA sampled noninvasively from eggshells after hatching.

In the face of the disproportionate effects of climate change, forming effective frameworks for discussing the vulnerabilities of small island developing states (SIDS) is more pertinent than ever. However, international development organizations have often used overly generic and ahistorical frameworks for understanding vulnerability, which advocate for increased tourism and coastal development as prescriptions for islands’ development. These ‘solutions’ instead exacerbate local experiences of vulnerability, which alternatively emphasize local epistemologies and histories of inequality and exploitation. This research focuses on community experiences across two resort-town destinations in the Dominican Republic: Bayahibe and Punta Cana. It asks: How is “vulnerability” experienced and understood by coastal communities in the eastern Dominican Republic? By employing ethnographic methods, this study reveals nuanced, in-depth perspectives on vulnerability while foregrounding local knowledges. This research is crucial to understanding the intersecting political, economic, and environmental conditions that SIDS face in the 21st century and how they have been reproduced throughout history, in the hopes of opening doors to imagining alternative development futures in SIDS, where patterns of environmental, economic, and socio-political exploitation are mended.