Upset for Milankovitch theory
Article Abstract:
A new analysis of oxygen isotope data strengthened the case against the long-accepted Milankovitch theory for what caused the ice ages. This paleoclimatic model holds that recurrent fluctuations in the Earth's orbit triggered the growth of glaciers by reducing the solar radiation reaching the mid-to-high latitudes. However, I.J. Winograd and co-workers examined the oxygen isotope levels from the Devils Hole aquifer in southern Nevada and found that the tested samples were 145,000 years old rather than 128,000 years old as required by the Milankovitch theory.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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Evidence for a higher pH in the glacial ocean from boron isotopes in foraminifera
Article Abstract:
The variation in the ocean pH from the last Glacial to the Holocene epoch is estimated by measuring the fractionation of boron isotopes. The fractionation occurs between the precipitated carbonate minerals and sea water, and the process is dependent on the pH of the sea water. The boron isotope fractionation is measured from the shells of foraminifera obtained from different periods. The method provides an accurate result, and shows that the Atlantic and Pacific oceans have a pH of 0. 3 units larger than the pH during the previous glaciation.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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Diminishing oxygen
Article Abstract:
A new interferometric method for determining how much oxygen is in the atmosphere should help in understanding the carbon cycle and its affect on CO2 levels and greenhouse warming. The interferometric method, developed by Ralph F. Keeling and Stephen R. Shertz, employs the refractive index of dry air to gauge the ratio of oxygen to nitrogen molecules to within five parts per million. The technique is expected to help determine the extent to which anthropogenic CO2 is exacerbating global warming and reducing atmospheric oxygen.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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