Mussel shells provide encapsulated information about their environment and we have used shell material to understand how ocean chemistry is changing. Both through past researchers on Tatoosh Island and in collaboration with the Makah Museum, we have archival material from several decades ago and multiple centuries ago.
Our work with modern and ancient shells has shown that the carbon isotopes of shells have shown a decline in 13C over the past decade, consistent with increasing fossil fuel uptake by the ocean. Our paper published in PLoS ONE in 2011 shows these results:
2011. Pfister, C. A., S.J. McCoy, J. T. Wootton, P. A. Martin, A. S. Colman, D. Archer. Rapid environmental change over the past decade revealed by isotopic analysis of the California mussel in the northeast Pacific.
Further, these animals had thicker shells in the past compared to modern animals (Pfister et al., in press, Proceedings of the Royal Society B).
We are grateful to the Makah Cultural and Research Center and the Makah Tribal Council, as well as the Olympic National Park for access to research materials.