Magnitudes of sea-level lowstands of the past 500,000 years
Article Abstract:
Techniques to estimate natural fluctuations in seal-level and global ice-volumes use fossil coral-reef terraces or oxygen-isotope records from benthic foraminifera. Significant values for minima, or lowstands, before the Last Glacial Maximum (LGM) are not produced by fossil reefs. However improved lowstand estimates, extending back to 500,000 years before present, are presented, based on evidence of extreme high-salinity conditions in the glacial Red Sea, combined with a simple hydraulic control model of water flow through the Strait of Bab-el-Mandab.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
User Contributions:
Comment about this article or add new information about this topic:
Foraminiferal boron isotope ratio as a proxy for surface ocean pH over the past 21 Myr
Article Abstract:
Data on foraminiferal boron isotopes can be used to determine past ocean pH for the past 21 Myr. Analysis of samples from a deep-sea sediment core shows that seawater boron concentrations and isotopic composition were both constant for the past 21 Myr. Based on foraminiferal isotope data, ocean pH was found to be 7.4 +/- 0.2. This value increased to 8. 2 +/- 0.2 about 7.5 Myr ago, and is almost the same today.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
User Contributions:
Comment about this article or add new information about this topic:
Past temperature and delta-18O of surface ocean waters inferred from foraminiferal Mg/Ca ratios
Article Abstract:
It has been established that, in a field-based calibration experiment, the variation of MG/Ca ratios with temperature is similar for eight species of planktonic foraminifera. Past temperatures reconstructed from Mg/Ca ratios followed faunal abundance and alkenone saturation.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2000
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Modelled atmospheric temperatures and global sea levels over the past million years. The twentieth century was the wettest period in northern Pakistan over the past millennium
- Abstracts: Attractiveness of scents varies with protein content of the diet in meadow voles. The response of native Australian rodents to predator odours varies seasonally: a by-product of life history variation?
- Abstracts: Estimating age of sea otters with cementum layers in the first premolar. Using cementum annuli to estimate Cantabrian chamois age
- Abstracts: Patterns of natal dispersal, turnover and dispersal costs in eastern bluebirds. Multiple mating by females selects for males that stay: another hypothesis for social monogamy in passerine birds
- Abstracts: Elastic properties of DNA revealed. Reading the minor groove