This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2020, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. The fellow’s project will address how human input of nutrients from fertilizer, sewage, or other sources into coastal waters may affect a group of clams called lucinids. Lucinid clams live buried in sand or mud and host symbiotic bacteria inside their gills. This is a mutually beneficial relationship because the bacteria use sulfur to make other needed molecules. Lucinid clams often live among the roots of seagrasses and enhance growth and survival because the sulfur compounds they remove from sediment are toxic. Healthy seagrass beds serve important functions by reducing erosion and providing a habitat for many commercially and recreationally important fish and shellfish. This project will analyze how lucinid clams and the symbiotic bacteria respond to changes in the coastal environment and how this may scale up to impact seagrass ecosystems. Understanding the relationships will be important for conservation and restoration efforts. To enhance the reach of the research to underrepresented groups and the wider community, the fellow will develop a public exhibit on the project, contribute to public science communication programs, and participate in coastal restoration practitioner meetings.
The fellowship project will use the bacteria-lucinid-seagrass symbiosis to address three specific questions: (a) Does the nutrient status of seagrass beds alter carbon and nitrogen sourcing by lucinids and their sulfur-oxidizing, nitrogen-fixing symbionts? (b) Does the nutrient status of seagrass beds change the proportional representation of symbionts in the lucinid gill microbiome? and (c) Do these alterations to lucinid metabolism and microbiome scale up to affect seagrass growth and condition? The project will comprise a field survey across a gradient of anthropogenic nutrient enrichment in coastal seagrass beds, complemented by a nutrient enrichment experiment in mesocosms. Carbon and nitrogen stable isotope analysis, gene expression assays, gene sequencing, sediment porewater chemistry, and standard metrics of seagrass growth and condition will be used to assess the effect of low- and high-nutrient conditions on the relative contributions of chemoautotrophy and nitrogen fixation to lucinid nutrition; the diversity of symbionts and other gill-associated bacteria in lucinid microbiomes; and consequent effects of lucinids on sediment biogeochemistry and seagrass health. The fellow will receive training in molecular biology techniques and bioinformatic analyses as well as advising in project management, mentoring, and teaching. The fellow will also participate in public outreach and restoration programs that will enhance the communication of research results to the broader community.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
