This award will support researchers based at the University of Washington's Friday Harbor Laboratories. The overall focus of the project is to determine how ocean acidification affects the integrity of biomaterials and how these effects in turn alter interactions among members of marine communities. The research plan emphasizes an ecomaterial approach; a team of biomaterials and ecomechanics experts will apply their unique perspective to detail how different combinations of environmental conditions affect the structural integrity and ecological performance of organisms. The study targets a diversity of ecologically important taxa, including bivalves, snails, crustaceans, and seaweeds, thereby providing insight into the range of possible biological responses to future changes in climate conditions. The proposal will enhance our understanding of the ecological consequences of climate change, a significant societal problem.
Each of the study systems has broader impacts in fields beyond ecomechanics. Engineers are particularly interested in biomaterials and in each system there are materials with commercial potential. The project will integrate research and education by supporting doctoral student dissertation research, providing undergraduate research opportunities via three training programs at FHL, and summer internships for talented high school students, recruited from the FHL Science Outreach Program. The participation of underrepresented groups will be broadened by actively recruiting URM and female students. Results will be disseminated in a variety of forums, including peer-reviewed scientific publications, undergraduate and graduate course material, service learning activities in K-8 classrooms, demonstrations at FHL's annual Open House, and columns for a popular science magazine.
The material world of ocean acidifcation The survival of many of our favorite coastal organisms depends on the integrity of their structures. Is their shell strong enough to deter predators? Is their attachment to rock secure in the face of strong currents? What happens to coastal marine communities when changing environmental conditions, such as ocean acidification (OA) or warming, alter how key biomaterials are manufactured and maintained? These questions guided our team of marine biomaterials experts based at the University of Washington’s Friday Harbor Laboratories (UW FHL). We targeted a suite of organisms (including mussels, seaweeds and other shellfish), each with a well-known biomaterial that serves a critical ecological function. Our research plan followed our unique ecomaterials approach; we use standard engineering techniques to detail how different combinations of environmental conditions affect the structural integrity of both calcified and non-calcified materials, then ask how such changes scale up to affect the performance of an organism under real-world challenges, such as crashing waves or crushing crab claws. Our ultimate goal is to provide insight into the range of possible biological responses to future changes in climate conditions. A new OAEL is bubbling with activity One of our first activities was to contribute significantly to the build-out of one of FHL’s newest facilities, the Ocean Acidification Environmental Laboratory (OAEL). Operating full swing in 2012, this state-of-the-art multi-user OA facility offers unique research and instructional opportunities for experimental manipulations with on-site monitoring of carbonate system parameters. The indoor mesocosms we developed were an essential tool for our work, allowing us to expose organisms to highly controlled environmental conditions. The mesocosms have been used widely by other researchers, from the University of Washington and several other institutions. Mussels lose their grip While the oyster has become the "poster child" for the harmful effects OA on shellfish, there is growing concern that mussels are at risk as well. OA is well known to slow growth and erode shells, but our recent work shows OA targets a non-calcified structure that is literally a mussel’s lifeline, the byssal thread. A mussel uses its foot to mold each stretchy byssal thread one at a time to form a strong tether to culture ropes, neighboring mussels and whatever else it can reach. In fact, a challenge all mussel growers face is episodic "fall-off", where water conditions cause mussels to produce weak byssus and up to 20-30% of the harvest slips off the ropes. We have observed similar mortality events in wild mussel populations as well. What exactly triggers weak mussel attachment is unknown, but our recent work has identified two likely culprits: low pH and high temperature. Using our highly controlled laboratory setting at the OAEL, we learned mussels produce weak, poor quality byssal threads if seawater pH is less than 7.6 or temperature is over 18°C. Do mussels on the culture ropes or natural shores ever experience these conditions? We are just beginning to find out, thanks to a new partnership with industry (Penn Cove Shellfish and Taylor Shellfish) and other federal and state agencies (NSF, NOAA, Washington DNR). We recently deployed in mussel rafts two sensor arrays that record temperature, pH, chl a, oxygen and salinity and post real-time to NANOOS (http://nvs.nanoos.org/Explorer, see "Penn Cove"). Our preliminary observations suggest mussels at depth (7 m) experience low pH conditions routinely, but the risk to mussels at the surface (1 m) is more likely high temperature coupled with low salinity and low food. We are now expanding our observations to other locations in the Salish Sea and the Olympic Peninsula. Calcified seaweeds in high CO2? We have also worked extensively on the effects of OA on calcified seaweeds, especially the coraline algae. These lovely pink seaweeds are an especially important component of our coastal flora; they provide key ecological functions by cementing carbonate fragments into reef structures and habitat for invertebrates seeking refuge from predation, wave exposure, and desiccation. In our OAEL mesocosms, were learned Corallina vancouveriensis fronds grew slower and produced weaker material under low pH conditions. Additionally, our field measurements show slower growth and weaker materials in the winter as compared to the summer. We are continuing to evaluate whether this seasonal change in growth and biomechanical properties is due to shift in pH or some other physical factors. In a related study, we learned OA delays and weakens the attachment of reproductive spores of both calcified and fleshy red algae. Altogether, these studies indicate OA can have negative effect on the reproduction, growth and survivorship of calcified seaweeds. The project also supported several education and outreach endeavors. One of the most substantial was Biomechanics 2012, a five week long summer course for graduate students at FHL. A major emphasis of this course was ecomaterials and the effects of OA.
