STABLE ISOTOPE DATA FROM DEEP-WATER ANTIPATHARIANS: 400-YEAR RECORDS FROM THE SOUTHEASTERN COAST OF THE UNITED STATES OF AMERICA

摘要

In this study, time-series stable isotope results (δ~(13)C and δ~(15)N) from three deep-water Leiopathes glaberrima (Esper, 1788) specimens collected off the southeastern coast of the United States of America and one specimen from the Gulf of Mexico are presented. The specimens were collected live in 2004 and are estimated to be 200-500 yrs old based on ~(210)Pb measurements and band counts. The δ~(13)C and δ~(15)N long-term trends are reproducible within and among specimens from a similar location, suggesting a common environmental influence. Three western Atlantic specimens have average δ~(13)C values of -15.7‰, -16.3‰, and -16.1‰, with the most depleted values from the oldest specimen. The oldest specimen records an enrichment in ~(13)C of 0.5‰ corresponding to the Little Ice Age. All three specimens show a depletion of ~(13)C over the past 150 yrs corresponding to the δ~(13)C Suess Effect. The fourth specimen from the Gulf of Mexico has an average δ~(13)C value of -16.4‰ and shows no trend in ~(13)C value with time. All four specimens contain an enrichment in ~(15)N over the most recent 75 yrs, with the largest enrichment (3‰) in the Gulf of Mexico specimen. This enrichment is likely a result of increased terrestrial effluent (sewage and manure) reaching the offshore specimens.