Variation in δ15N from shell-associated organic matter in bivalves: Implications for studies of modern and fossil ecosystems

Nitrogen stable isotopes (δ15N) of organic matter can aid in the reconstruction food webs and, when applied to fossil systems, may help resolve uncertainty about trophic position and provide tests for hypotheses developed using traditional paleoecological techniques. However, order use those values reconstruct relationships ecosystems assess changes their dynamics, an understanding variability isotopic signatures within individuals across populations is critical. The purpose this study develop a methodology by which characterize nitrogen isotope bivalve shells propose approach effective paleoceanographic studies such data. Here we present high-resolution sclerochronological whole-shell δ15N shell-associated derived from modern Spisula solidissima bivalves three different localities. High-resolution vary 4‰ over sampled life history, reflects interplay factors as diet, physiological change ontogeny, background dissolved nutrient nitrogen. A significant correlation temporally aligned with δ18O at lags suggests that has seasonal control. Furthermore, enrichment following peak primary productivity region turnover nutrients driver variability. Unfortunately, record does not always yield well-preserved whole shells, working limited shell fragments unlikely capture full range variation exhibited shell. To end, also analyzed field-collected sub-fossil set δ15N. sample demonstrates 5‰ among individual similar observed serially-sampled shells. This likely might expect see population collected single horizon record. Studies involving paleo setting should analyze numerous specimens stratigraphic unit population. Moreover, it important compare multiple coeval taxa each taxa.