We examined the long-term effects of near-future changes in temperature and acidification on skeletal mineralogy, thickness, and strength in the sea urchin Tripneustes gratilla reared in all combinations of three pH (pH 8.1, 7.8, 7.6) and three temperatures (22 °C, 25 °C, 28 °C) from the early juvenile to adult, over 146 days. As the high-magnesium calcite of the echinoderm skeleton is a biomineral form highly sensitive to acidification, and influenced by temperature, we documented the MgCO3 content of the spines, test plates, and teeth. The percentage of MgCO3 varied systematically, with more Mg2+ in the test and spines. The percentage of MgCO3 in the test and teeth, but not the spines increased with temperature. Acidification did not change the percentage MgCO3. Test thickness increased with warming and decreased at pH 7.6, with no interaction between these factors. In crushing tests live urchins mostly ruptured at sutures between the plates. The force required to crush a live urchin was reduced in animals reared in low pH conditions but increased in those reared in warm conditions, a result driven by differences in urchin size. It appears that the interactive effects of warming and acidification on the Mg2+ content and protective function of the sea urchin skeleton will play out in a complex way as global climatic change unfolds.

The relative abundance of the isotopes of carbon has been measured in samples of oil and gas from 32 wells in the Silica and Ellinwood Fields of Barton and Rice Counties, Kansas, and 3 wells in Oklahoma, Texas and Wyoming, as well as in surface vegetation, hydrocarbons from well cuttings, and carbon dioxide desorbed from soil. For the samples from Silica and Ellinwood Fields, [Formula: see text]. Relative abundance appears to be independent of the source of petroleum, but is about 1.6% lower for vegetation. It is concluded that this quantity cannot be used to distinguish sources of petroleum and that its use to determine the origin of soil hydrocarbons requires an accuracy of measurement not hitherto attainable.