Marine Bivalve Feeding Strategies and Radiocarbon Ages in Northeast Atlantic Coastal Waters

Abstract

Marine mollusk shells have been extensively used to provide radiocarbon (14C)-based chronologies in paleoenvironmental and archaeological studies, however uncertainties in age measurements are introduced because secondary factors such as vital effects and diet may influence 14C incorporation into these shells. Deep burrowing and deposit feeding mollusks, in particular, may incorporate “old” carbon resulting in apparently older ages than their contemporary environment. In this study, we present paired 14C and stable isotope (δ13C and δ18O) measurements for nine species of known-age bivalves having different feeding strategies and collected in six localities around the NE Atlantic. We exclude potential “old” carbon contamination in these known-age mollusk shells, acquire a better understanding of local ecology and provide an improved context for the environmental interpretation of 14C ages. Our results indicate that, in the NE Atlantic, marine mollusk-derived 14C ages provide a reliable basis for environmental and archaeological investigation, independently of vital effects and differences in microhabitats, feeding strategies and sample location—all of which are apparent from stable isotopes.

Palaeoenvironmental reconstruction of Loch Duart (NW Scotland, UK) since the Last Glacial Maximum: implications from a multiproxy approach

“…A Δ R of −126 ± 58 years (previously 24 ± 58 years using Marine13) (Harkness 1983) was deemed appropriate considering the proximity to core location. This Δ R is comparable with the averaged Δ R from the five nearest data points (Harkness 1983; Cappelli & Austin 2020) in the CALIB marine reservoir correction database (Reimer and Reimer, 2001). Therefore, a local Δ R of −126 ± 58 was used when calibrating with the Marine20 curve.…”

Identification of Atlantic water inflow on the north Svalbard shelf during the Holocene

“…The uppermost ∼10 cm of the core dates to 194 cal yrs BP. It should be noted that it is possible that cold water molluscs may produce somewhat older marine reservoir values compared with other species due to the inclusion of old carbon or the vital effect as suggested by Forman and Polyak (1997) and Lo Giudice Cappelli and Austin (2019).…”

On the varied impact of the Storegga tsunami in northwest Scotland

“…14 C ages are recalibrated using INTCAL20 or MARINE20 (*) in CALIB 8.2 (Stuiver & Reimer, 1993;Heaton et al, 2020;Reimer et al, 2020). The marine date is calibrated using a ΔR of −111 ± 50 calculated from the mean of the six nearest marine reservoir ages (within 42 km of Dubh Lochan) taken from the Marine Reservoir Correction database (Harkness, 1983;Reimer & Reimer, 2001;Cappelli & Austin, 2020). [Color figure can be viewed at wileyonlinelibrary.com] would raise the tsunami-predicted heights by the same amount, and potentially allow multiple waves into the basin.…”