Freshwater Mussel Ecological Stoichiometry: C, N, and P Relationships.

One of the goals of ecological stoichiometry is to understand how the relative proportions of chemical elements in organisms influence ecological interactions such as foodweb dynamics and ecosystem processes. Freshwater mussels, with large biomass and long lives, have the potential to be highly influential in foodwebs and ecosystems. The objectives of our study were to investigate the species, spatial, and temporal patterns in mussel stoichiometry. Little Darby Creek mussels were significantly different across seasons and sites for C:N ratios and N:P ratios. Spring C:N were highest (5.22), while lowest in autumn (4.8) and N:P was highest in the spring (5.1) and lowest in the autumn (4.65). Site differences also were observed with C:N of 5.23 and 4.79 and N:P of 5.08 and 4.64, respectively. Meanwhile, Ouachita River mussel C:N was significantly different between species, while N:P was significantly different among seasons and between sites, but not species. Overall, C:N of Ptychobranchus occidentalis (5.52) was higher than Actinonaias ligamentina (4.95). Seasonal N:P was highest in autumn(9.92)and lowest in the spring (6.72) and site N:P differences of 8.53 and 7.39 also were observed. Variability in these ratios suggests variability in mussel stoichiometry could lead to variability in foodwebs and ecosystems.