Oxygen and carbon isotopic composition of living planktonic foraminifera from the northeast Pacific Ocean
| Autor: | Michael I. Kahn, Douglas F. Williams |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Calcite
biology Paleontology Globigerina bulloides Plankton Oceanography medicine.disease biology.organism_classification Pachyderma Foraminifera chemistry.chemical_compound chemistry Standing crop medicine Seawater Hydrography Ecology Evolution Behavior and Systematics Geology Earth-Surface Processes |
| Zdroj: | Palaeogeography, Palaeoclimatology, Palaeoecology. 33:47-69 |
| ISSN: | 0031-0182 |
| DOI: | 10.1016/0031-0182(81)90032-8 |
| Popis: | Stable isotopic analyses were performed on the tests of five species of living planktonic foraminifera which are important in paleoclimatic studies of high-latitude Late Cenozoic sequences. All but two of the samples used are from horizontal plankton tows of known depths between 0–500 m in the northeastern Pacific Ocean (50°N, 145°W). In situ hydrographic, seawater stable isotopic, and quantitative species-distribution data are used in the interpretation of the results. All of the species show depletions in both 18 O and 13 C in their calcite tests relative to calcite precipitated in isotopic equilibrium with ambient seawater. Estimates of the departures from isotopic equilibrium range from −0.35‰ in Globigerinita glutinata to −2.24‰ in Neogloboquadrina pachyderma (sinistral) with respect to δ 18 O, and from −0.5‰ in Orbulina universa to −4.34‰ Globigerina bulloides with respect to δ 13 C. The δ 18 O data suggest that primary test growth for individual species is not restricted to the depth interval where highest total standing crop values occur. Oxygen and carbon isotopic depth rankings for G. bulloides, N. pachyderma and G. glutinata reflect the relative magnitude of the vital effect in these species and not necessarily different depth habitats. The vital effect for δ 18 O in these species remains approximately constant with changing temperature/water depth, while the vital effect for δ 13 C strongly decreases with increasing depth. Temperature also does not appear to directly affect the coiling ratios of G. bulloides , but a significant negative correlation exists between the percentage of sinistrally coiled G. glutinata and water temperature. |
| Databáze: | OpenAIRE |
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