Seasonal variation in stable oxygen and carbon isotope values recovered from modern lacustrine freshwater mollusks: paleoclimatological implications for sub-weekly temperature records

• Published in: Journal of paleolimnology Vol. 26; no. 2; pp. 205 - 218
• Main Authors: Wurster, Christopher M, Patterson, William P
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.08.2001
• Subjects: Carbon isotopes; Climate change; Dreissena polymorpha; Fractionation; Freshwater; Freshwater mollusks; Lakes; Mollusca; Mollusks; Paleoclimate; Seasonal variations; Sphaerium simile; USA, New York, Keuka L; USA, New York, Science L; Watersheds
• ISSN: 0921-2728; 1573-0417
• DOI: 10.1023/A:1011194011250

A fingernail clam (Sphaerium simile, Sphaeriidae) from Science Lake, a small watershed located in Allegany State Park, New York, USA and a zebra mussel (Dreissena polymorpha, Dreissenidae) from Keuka Lake, New York, the third largest Finger Lake of central New York, were selected to evaluate the applicability of using δ^sup 18^O^sub (CaCO3)^ and δ^sup 13^O^sub (CaCO3)^ values for sub-weekly climate records. Seasonal variation in δ^sup 18^O^sub (CaCO3)^ values was compared with predicted equilibrium values to test the hypothesis that lacustrine molluscs produce shell aragonite according to environmental variables. For the purpose of comparison, aragonite temperature-fractionation equations determined by Grossman& Ku (1986) and Patterson et al. (1993) were used. Sphaerium simile appears to produce δ^sup 18^O^sub (CaCO3)^ values predicted by Patterson et al. (1993), while Dreissena polymorpha produces δ^sup 18^O^sub (CaCO3)^ values in agreement with Grossman & Ku (1986). We attribute the difference to family-specific temperature-fractionation relationships. Because both types of mollusc record climate variables with a high degree of integrity, they should each serve as excellent paleoclimate proxies. The fingernail clam collected from a small watershed exhibits higher variation about the seasonal pattern than did the zebra mussel collected from a large watershed. This is attributed to the increased sensitivity of the small watershed to storm perturbation. Analysis of fossil molluscs from such watersheds might be useful in discerning paleo-storminess.[PUBLICATION ABSTRACT]