| Autor: |
Michael J. S. Tevesz, John P. Coakley, Jodie E. Smith, Michael J. Risk |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Journal of Great Lakes Research. 23:307-316 |
| ISSN: |
0380-1330 |
| DOI: |
10.1016/s0380-1330(97)70914-6 |
| Popis: |
We present the first δ18O and δ13C data from mollusc aragonite from Lake Erie for the 4.6–0.2 ka (4600 BP to 200 BP 14C yrs) time interval and describe single and composite species isotope trends. Composite species δ18O data show an almost 2.0%o increase from 3.3 to 3.0 ka followed by a nearly 2.5%o decrease at 2.8 ka. Oxygen isotope values then fluctuate by < l‰ until 0.2 ka. This trend in oxygen values is also evident in single species analyses of Sphaerium striatinurn. The most dramatic changes in isotope values, which occur from 3.3–2.8 ka, may reflect a pattern of water level changes in Lake Erie which occurred during the Nipissing flood and its lower water aftermath. Carbon isotope data show progressively more 13C enriched values from 4.6 ka (averaging–6.5‰ PDB) to the present (–0.57‰). This trend may reflect the dilution of isotopically light CO2 from the oxidation of organic matter due to rising lake levels. The short-term increase in δ18O values is coupled with a corresponding decrease in δ13C values. A similar pattern for Lake Erie prior to 10.5 ka was also associated with a lowering of water levels in the lake. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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