Award: OCE-2050129

This collaborative project (together with NSF grants: 2050273 and 2050345) examined how dense aggregations of marine mussels—important ecosystem engineers on rocky shores—create unique chemical environments within their beds, and how these “microclimates” affect the mussels themselves and the broader ecological communities they support. Our work focused on understanding how mussel beds modify their surrounding water chemistry through respiration, and how those effects vary depending on environmental conditions like water flow and temperature.

Intellectual Merit. To understand the dynamics inside mussel beds, we developed custom experimental systems to measure how respiration rates in mussels change with water temperature and flow speed. These physiological response curves were generated for four species of mussels—including native and invasive species—as well as their hybrids. This allowed us to explore species-specific differences and how mussels perform under stress.

We also designed a novel 3D-printed flow sensor capable of measuring water velocity within the tight spaces between mussels—an area notoriously difficult to study with conventional tools. Field deployments of this sensor in shallow and deep mussel beds revealed that water flow inside dense beds can be reduced by up to 70%, creating conditions that can lead to oxygen depletion and low pH.

In parallel, we showed that commonly used lab temperature regimes can misrepresent the real-world conditions mussels experience. By using real field temperature data from mussel beds in the Pacific Northwest, we designed laboratory experiments that mimicked natural thermal fluctuations. Mussels exposed to these realistic temperature regimes showed broader and more accurate performance responses than those tested under simplified alternating high/low tempertures conditions. This work highlights the importance of using ecologically relevant conditions when predicting species responses to environmental stress.

All datasets—including respiration rates, gene expression, and mussel bed temperature profiles—have been archived in public repositories (e.g., BCO-DMO, Dryad) for use by other scientists.

Broader Impacts. This project provided hands-on research experiences for over 30 undergraduate students, including six REU students and two full-time research technicians. Students participated in all aspects of the research—from fieldwork and lab experiments to data analysis and scientific communication. Several students presented posters at national conferences, and many have gone on to graduate and professional schools. 

In terms of outreach, we launched a large science communication effort to raise public awareness about the ecological value of mussel beds. An undergraduate student (double majoring in biology and art) created an illustrated poster and sticker series titled “Mussel Bed Diversity in the Pacific Northwest.” Over 200 posters and 1,000 stickers were printed in both english and spanish and distributed to aquariums, museums, high school/univesity students, and marine labs across the U.S., Canada, the UK, Spain, Australia, and New Zealand. The materials include a QR code linking to a website with more information and a request form for free poster copies. 

Additionally, students participated in public outreach events at a local shellfish farm, where they shared mussel research with visitors and engaged them in marine science education. These events helped connect the community with current environmental science and demonstrated the direct relevance of scientific research to coastal ecosystems.

Conclusion. This project has deepened our understanding of the dynamic microenvironments formed within mussel beds and the complex ways that mussels respond to multiple environmental stressors. It also fostered extensive student training, public engagement, and cross-disciplinary innovation in sensor design. By combining ecological physiology, engineering, and education, the project contributes valuable insights into how foundation species—and the communities they support—may fare under environmental stress.

 

Last Modified: 06/30/2025
Modified by: Michael T Nishizaki