Research in the Tracy Lab addresses 5 major themes:
1. Parasite Co-infection in Marine Hosts and Ecosystems
Co-infection is the reality for organisms living in a natural environment, but many questions remain about the role of multiple parasites in the wild. Laboratory research points to important ways that parasites can interact within a host, which can lead to both ecological and evolutionary consequences. Research in the Tracy Labcontributes to the growing understanding of co-infection by evaluating the importance of environmental factors, host resources, and host immunity in marine organisms, including both oysters and sea fan octocorals.
Key words: Foundation species, seascapes, ecosystem function
Oyster reefs are important for coastal ecosystems because they provide habitat and filter water. In the Chesapeake Bay, Crassostrea virginica is also a culturally and economically important species.
One major branch of our research asks: How do the abiotic environment, management decisions, and species interactions affect habitat on oyster reefs? We use large-scale field studies, field experiments, and data synthesis to address this question. In addition to advancing the understanding of oyster ecology, our work aims to support the management of oyster reefs in Chesapeake Bay and around the world.
While oysters are economically and ecologically important organisms, they are part of a broader ecosystem that includes working landscapes and seascapes. I am collaborating with terrestrial ecologists to bridge the land-sea interface and seek a broader perspective on the impact of environmental change on the Chesapeake Bay watershed.
Collaborators: Matthew Ogburn (@OceanOgburn) & Fisheries Conservation lab members; Kim Komatsu (@drkimkomatsu); Amy Hruska (@ecologist_amy); Zofia Knorek (@zofiaknorek); Amy Johnson; Katrina Lohan; Smithsonian Working Land and Seascapes (@SmithsonianWls)
Host-parasite interactions are a normal part of healthy ecosystems, but environmental stressors can tip the balance in favor of the parasite. For example, conditions that lead to suppressed host immune function can allow a parasite to devastate a host population. In addition to the many large scale stressors that marine hosts must contend with, there are important local stressors that further influence their ability to survive, grow, and reproduce. Pollution is a local stressor that can have devastating effects on marine life, but may also be more tractable to resolve at a local scale. Relevant publications: Linking sewage pollution and water quality to spatial patterns of Porites lobata growth anomalies in Puako, Hawaii
Outbreaks of marine infectious diseases have caused widespread mass mortalities, but the lack of baseline data has precluded evaluating the hypothesis that disease is increasing in the ocean. We used a literature analysis to assess multi-decadal trends in marine disease across the recent decades of dramatic, global change.
The host immune system is central to understanding the ecology and evolution of infectious disease. In addition, studying immunity in marine systems can shed light on the evolution of immunity given the ancient immune systems at work in many marine organisms.
We are developing several projects to understand the oyster ecosystem as a combination of sanctuary reefs, wild harvest reefs, and aquaculture as these three sectors all make important contributions. This includes our work on habitat, as harvested areas contribute different but important habitat (see #2 above). We are looking for more partners at this time, so please reach out if you would like to discuss potential business/ research collaborations.
6. The Microbiome of Foundation Species
Oyster microbial communities
Bacteria in oysters are part of the host microbiome and may affect how oysters respond to changing environments and global change stressors. We are studying the spatial ecology of oyster-associated bacteria to understand their role in host health and disease.
Coral microbial communities
Microbes can play an important role in both healthy and diseased corals. In addition to the microbes that cause disease, there are also microbes that are essential for healthy function and provide critical services to the coral host. I am interested in the role the environment plays in shaping these microbial communities and my dissertation research investigates this question in G. ventalina. In the future, I hope to further pursue questions about the microbial communities in complex environments and the ensuing effects on host populations over short and long time scales. Relevant publications: Persistent shifts in Caribbean coral microbiota are linked to the 2010 warm thermal anomaly
Invasive species, local adaptation, inclusive teaching, life history trade-offs
Parguera, Puerto Rico
Parguera, PR has been the home base for our octocoral research, which required extensive disease surveys and laboratory experiments. This research was made possible by the scientists and staff at Isla Magueyes, home of the Department of Marine Sciences for the University of Puerto Rico at Mayagüez.