Project: RUI: Collaborative Research: Understanding bioerosion from individuals to ecosystems: the impacts of biotic and abiotic stressors on sponge erosion of oyster reefs.

NSF Award Abstract:

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

Oyster reefs, historically one of the most important economic and ecological habitats in the U.S., have suffered major losses due to declining water quality, overharvesting, and diseases. In estuaries across the country, many large-scale conservation, restoration, and research efforts have been implemented to help reestablish oyster reefs. To better understand and protect these ecosystems, this project focuses on understanding the breakdown (erosion) processes that are occurring in areas where oysters are found. Erosion facilitated by living organisms (called bioerosion), such as boring sponges, is problematic for oyster aquaculture and restoration efforts, yet little is known about the processes that influence the rates of sponge bioerosion on oyster reefs. To address this knowledge gap, this research is evaluating two factors thought to affect sponge bioerosion rates: the presence of nudibranchs that prey on boring sponges and ocean acidification. The project uses manipulative experiments and collects sequence data to 1) determine the ways that Atlantic and Pacific boring sponge species respond to predators under different ocean acidification conditions, and 2) compare the short- and long-term effects of predator presence and acidification on sponge bioerosion rates of oyster reefs. The experimental data collected will be used to model bioerosion on simulated oyster reefs to better understand how these two factors influence overall oyster reef carbonate changes. This research informs better management practices for controlling sponge bioerosion for oyster growers, aquaculturists, and restoration programs and improve our understanding of how biotic and abiotic stressors act individually and together to alter sponge bioerosion behavior. This project strategically links undergraduate students at a small liberal arts college (Occidental College) with collaborators at an R1 institution (Louisiana State University), an R2 Hispanic-Serving Institution (University of California Merced), and will incorporate over 40 undergraduate students in various aspects of the project, including intensive field and lab experiences, bioinformatics workshops, and classroom-based projects. Students will also help create open-access materials (both written and video-based) that detail the research methods, protocols, and analyses and all data and code will be made publicly available to promote transparency and reproducibility in science. Results and open-access materials will be broadly disseminated via scientific conferences, peer-reviewed journals, industry meetings with shellfish growers and aquaculturists, and social media outlets.

Organism-mediated substrate removal, or bioerosion, has a negative effect on oyster reef growth and resilience; bioeroding sponges are considered one of the most destructive bioeroding taxa in these ecosystems. While many abiotic stressors have been found to influence sponge bioerosion (e.g. acidification, temperature, etc.), the ability of bioeroding sponges to react to biotic stressors, such as predation, remains unexplored. This project uses experimental investigations, transcriptome sequencing, and mathematical modelling of a nudibranch-sponge predator-prey model to evaluate the responses of bioeroding sponges to biotic and abiotic stressors. The research determines how sponges modify their relative investment in chemical and mechanical bioerosion in response to predation pressure and seawater acidification at the phenotypic and transcriptomic levels. The project: (i) explores whether predator presence directly elicits bioerosion as an inducible defense in boring sponges, (ii) quantitatively assesses the phenotypic and transcriptomic response of boring sponges to predation and acidification over different temporal scales, and (iii) determines whether sponge response to these abiotic and biotic factors are similar across phylogenetic and geographic scales. The research advances the scientific understanding of sponge bioerosion in non-tropical, non-coral carbonate ecosystems and examines the ubiquity of these processes across heterogeneous geographic regions. This project has the capacity to transform our understanding of the biotic and abiotic interactions between boring sponges and the ecosystems where they reside.

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.