Temperate Corals & Microbial Ecology

Headed by Dr. Koty Sharp, the research group investigates the microbial ecology of corals, with the ultimate goal of determining how interactions with microbes, both beneficial and pathogenic, impact the fitness and survival of benthic marine invertebrates. Our student-led research team has the opportunity to get hands-on experience with laboratory and field research during the academic year and throughout the summer months.

This work is especially important as marine species, communities, and ecosystems face the emerging threats of climate change. Much of our work is focused on the temperate coral Astrangia poculata, an emerging model for studying coral-microbe symbiosis and physiology. 

The Sharp Lab

Learn more about the Sharp Lab for Temperate Coral and Microbial Ecology Research

Research in the Sharp Lab is centered on the diversity, dynamics, and distribution of microorganisms associated with corals and coral reef organisms. Like most animals on the planet, corals harbor diverse but specific communities of microorganisms (their "microbiome") that have direct influence on their health and fitness. Based in New England, we focus our efforts primarily on the curious, temperate, local coral, Astrangia poculata, and its microbiome, in order to learn more about how the microbial community composition and activity is regulated by the host, by other symbiotic partners, and by environmental factors.  It is especially critical to understand how microbes respond to environmental change and mediate the health and fitness of animals in marine ecosystems, especially in the face of changing oceans, changing coastlines, and changing climate. Below are some of our current Astrangia projects.

Microbial Ecology and Multipartner Symbioses

​Using the facultatively symbiotic coral Astrangia poculata as our study organism, we are exploring the principles of microbiome assembly in corals, and teasing apart how microbiome composition and activity is regulated and maintained.  Astrangia poculata is unlike most tropical corals - it occurs with variable levels of Symbiodinium in its tissues,and it can withstand extreme temperature fluctuations. Therefore, A. poculata offers us the unique ability to test the influence of facultative photosynthetic symbiosis and seasonal temperatures on microbiome structure. Using microscopy and next-generation DNA sequencing technologies, we have found that season, not symbiont state, influences the microbiome structure in A. poculata in Rhode Island.  Further, in laboratory experiments, we found evidence that photosymbionts exert some influence over the microbiome’s recovery from disturbance. Current collaborative work in our lab describes a high-resolution time series of the A. poculata microbiome response to cold winter temperatures. Our hope is to translate our findings in A. poculata to informed management solutions for tropical coral species, which currently are in massive decline due to human-induced ocean warming events.

Astrangia poculata Husbandry and Reproduction

As part of our goal to establish Astrangia poculata as a useful model system for studying various aspects of symbiosis in cnidarians, we coordinate a multi-institutional collaboration that uses the RWU facilities to develops methods for scalable A. poculata husbandry, spawning, fertilization, and larval settlement.

Astrangia poculata and Microplastics Pollution

Current research suggests that there are hundreds of millions of tons of plastics in our oceans. Millions of tons of plastic continue to enter the oceans each year. The macroplastics that enter the ocean often get weathered down into microplastics, which have been found in oceans all across the world, even in the most remote regions and at the deepest depths. Microplastics are consumed by a variety of marine organisms, especially filter feeders and suspension feeders.  In our lab, we are working to learn more about the microbial ecology of microplastics pollution in Narragansett Bay, and how that impacts marine invertebrate-bacterial interactions. Using Astrangia poculata, a local heterotrophic coral species, we are learning more about the microbial aspect of microplastics pollution. This ongoing research is funded by the Rhode Island IDeA Network of Biomedical Research Excellence (RI-INBRE SURF), the Rhode Island NSF Established Program to Stimulate Competitive Research (EPSCoR SURF) programs, and the RWU Fund to Promote Scholarship and Teaching. Read our publication on Astrangia, plastics, feeding behavior, and microbes.

​Antibacterial Compounds and the Astrangia Microbiome

Our lab created and is maintaining a library of bacterial strains (The Astrangia Culture Collection) that we have isolated from Astrangia poculata, to learn more about bacterial production of antimicrobial compounds and their potential ecological roles, and to explore their potential use for aquaculture, clinical, and biotechnology applications.

Click here to learn more about student-led applied research in the Sharp Lab, and the national Temperate Coral Research Conference, which we co-host annually.