Comparing contemporary biogeochemical archives from Mercenaria mercenaria and Crassostrea virginica: Insights on paleoenvironmental reconstructions

Reconstruction of past environmental conditions from modern and fossil organisms is predicated on predictable biological responses to variation. Thus, understanding how different species record commonly experienced critical. This particularly important in settings where multiple biogeochemical archives are available for study (e.g., a rich assemblage). Previous work has documented species-specific thermal tolerances growth rates, which suggests proxy-based reconstructions may reflect combination controls To investigate this potential complication, we compared oxygen isotope (δ18O) profiles shells two contemporary marine bivalve mollusks (Mercenaria mercenaria Crassostrea virginica) growing the same locality (Cape Lookout region, North Carolina, USA). Carbonate samples (δ18Oc) were collected shell material deposited between August 2016 April 2019. These data calibrated with predicted δ18Oc (aragonite calcite) calculated high resolution records (hourly temperature weekly water samples). M. specimens periodically stained calcein during interval, facilitating transformation into time domain. C. virginica fit directly profile. Our results suggest that living Cape region capable depositing throughout year. Shell both slows significantly, or halts altogether, short term large magnitude freshwater input events. examined show strong preference warmest hours day. observation optimal temperatures lie close upper limit recorded at site. does not warm cold major conclusion place aspects conditions. Nevertheless, our findings contain more detailed than previously thought. Future studies should focus high-resolution, short-duration calibrations time, location, resolution.