Paleoenvironmental reconstruction through geochemical analysis of long-lived bivalve shells (Mercenaria stimpsoni)

Abstract

Unlike the tropical to subtropical areas where reef-building corals are distributed, high latitude paleoenvironmental records with high temporal resolution over the past centuries are scarce. Long-living bivalve shells can be a good candidate for paleoenvironmental recorders. In such a situation, it has recently been revealed that modern cold-water bivalve Mercenaria stimpsoni (Stimpson's hard clam) living in shallow seafloors of North Japan have a lifespan of over 100 years. In this review, details of sclerochronological analysis and analytical procedures oxygen stable isotope and radiocarbon measurements of M. stimpsoni shells collected from shallow seafloors of Funakoshi Bay and Otsuchi Bay are described. Then, ecological (e.g., shell growth patterns) and paleoenvironmental (e.g., oceanic currents, tsunamis) findings that were obtained through these analyses are described.