Premium
Geoducks ( Panopea abrupta ) as isotopic bioarchives of seasonality in the climate of British Columbia
Author(s) -
Nielsen Jan Kresten,
Nielsen Jesper Kresten
Publication year - 2009
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-008-0571-4
Subject(s) - oceanography , δ13c , stable isotope ratio , sea surface temperature , pacific decadal oscillation , isotopes of carbon , isotopes of oxygen , shell (structure) , environmental science , physical geography , geology , geography , ecology , biology , total organic carbon , physics , materials science , geochemistry , quantum mechanics , composite material
Geochemical analyses of geoduck shells ( Panopea abrupta ) have yielded new high‐resolution isotope records of individual growth increments. The geoducks, which were collected from Parry Passage at Langara Island, British Columbia, are the most northern specimens that have yet been analyzed for stable oxygen and carbon isotopes. The isotope records represent the entire shell growth during the calendar years 1918, 1987, and 1991. The analyses showed that values of δ 18 O shell and δ 13 C shell vary within their growth increments. Temperature derived from δ 18 O shell is consistent with modern instrumental data of sea‐surface temperature. High‐resolution δ 18 O records from individual growth increments substantiate the assumption that they are formed annually. The instrumental data indicate that the growth season was from May through October/November. The sea temperature became gradually warmer during the beginning of the growth season, and decreased steeply during autumn. Similar subannual trends can be recognized in shells growing almost a century ago. Correlation between δ 18 O shell and δ 13 C shell is negative for 1917–1919 and 1986–1988, whereas the correlation is positive for 1990–1992. Differences in correlation may be related to the composition of available food particles, i.e., algal blooms and plant debris. The food composition is partially affected by the Pacific Decadal Oscillation (PDO). These findings have major implications for the understanding of the interpretation of carbon isotopes in marine bivalves. Because of their spatial and temporal distribution, the geoduck shells are highly suitable for oceanographic reconstructions using stable‐isotope analysis and sclerochronology. Furthermore, the large shell size and thickness and their deeply buried life position suggest a high preservation potential in ancient deposits. It is well known that the genus Panopea has a long‐range fossil record.