The American Museum of Natural History researchers discovered that the porosity in mussel shells along the East Coast of the United States has increased over the past 120 years, possibly because of rising water temperatures. The study compared modern mussel shells with specimens from the Museum’s historic collection.
The study, which focused on specimens in the Museum’s historic collection, has been published in the journal PLOS ONE.
Leanne Melbourne, a Kathryn W. Davis postdoctoral fellow in the Museum’s Master of Arts in Teaching program and the lead author on the study, emphasized the importance of mussels. She stated, “Mussels are important on so many levels: they provide habitats on reefs, they filter water, they protect coasts during storms, and they are important commercially as well — I love mussels and I know many other people do, too.” Melbourne also highlighted the threat of human-caused environmental changes on the ability of mussels and other mollusks to form their shells, stating the need for a better understanding of this issue.
Understanding the potential future risks is crucial in addressing how ocean warming and acidification will impact the blue mussel (Mytilus edulis). Previous research has primarily relied on laboratory experiments to study the effects of these environmental changes on the structure and function of these marine organisms. In contrast, Melbourne utilized the Museum’s extensive bivalve collection, dating back to the late 1800s, to track natural environmental changes.
The use of museum collections is advantageous in demonstrating long-term changes. Organisms in natural habitats undergo gradual exposure to changing conditions, allowing for more time to adapt and observe the effects.The stressor,” said co-author Nathalie Goodkin, a curator in the Museum’s Department of Earth and Planetary Sciences. “Laboratory experiments are excellent for isolating individual factors, but that’s not how things operate in the real world.”
Melbourne focused on shells collected in the early 1900s and the 1960s from five sites: Nahant Bay in Massachusetts, the southern end of Cape Cod, the tip of the Long Island Sound, western Long Island Sound, and New York Harbor. She then paired these historic specimens with modern samples from the same sites and conducted a series of comparisons including the thickness of the shells, their surface area.
The research discovered that modern shells have a higher level of porosity compared to shells from the 1960s and early 1900s. This suggests that the rise in temperature over the years has led to an increase in shell porosity. The North Atlantic region has seen seasonal temperature increases of up to 3 degrees Celsius (5.4 degrees Fahrenheit) since 1902, but this warming has not been consistent, which could explain the differences in porosity seen in older shells. The North Atlantic Oscillation, a weather phenomenon that brought colder-than- usual temperatures, may also have had an impact on these variations in porosity.
The anticipated water temperatures from the 1960s also play a role. Porosity can impact the strength of mollusk shells, resulting in weaker shells that are more susceptible to damage. Further research is necessary to understand the potential impact of temperature changes on mussel populations. According to Melbourne, the formation of robust shells is crucial for mussel and mussel reef ecosystem services. If weaker shells are formed, the organisms may be at risk of breakage, leading to potential loss. However, a more in-depth analysis at a materials science level is needed to fully comprehend the situation.
Journal Reference:
- Leanne A. Melbourne, Nathalie F. Goodkin. Using Museum collections to assess the impact of industrialization on mussel (Mytilus edulis) calcification. PLOS ONE, 2024; 19 (4): e0301874 DOI: 10.1371/journal.pone.0301874