\"1.Figure 2 depicts the PETM as a temperature spike of several Celsius degrees
ID: 293271 • Letter: #
Question
"1.Figure 2 depicts the PETM as a temperature spike of several Celsius degrees that took place approximately ________ million years before present. [Note that in Figure 2 the most ancient time is to the right and the most recent is to the left, that is, the direction of time is from right to left.] [ ]41 [ ]50 [ ] 3.From the discussion in item 2 above, it can be inferred that the oxygen isotope ratio (18O:16O) is a proxy for ________. [ ]temperature [ ]glacial ice volume [ ]both of these 4.Examine the top graph in Figure 3. Isotopic studies of bottom-dwelling foraminifera fossils recovered from deep-sea sediment cores from sites described in the Figure 3 caption show that with the onset of PETM there was a rapid ________ in the carbon isotope ?13 value (note scale on left increases upward). This is indicative of a large increase in the concentration of the atmospheric greenhouse gases carbon dioxide (CO2) and methane (CH4). [ ]increase [ ]decrease 5.The middle panel has scales for two different measures. Note that the oxygen isotope ?18 scale on the left increases downward, while the water temperature scale on the right increases upward. The middle panel shows that a relatively rapid decrease in oxygen isotope ?18 values was associated with a dramatic ________ in seawater temperature of approximately 5 Celsius degrees. [ ]increase [ ]decrease 6.The bottom panel in Figure 3 reports the percentage of calcium carbonate (CaCO3) in solution in seawater compared to the amount if the liquid were saturated with CaCO3. The shows that during the period prior to and the period after the PETM event, ocean waters at the two depths measured (4.8 km and 2.6 km) were approximately ________ saturated with calcium carbonate (CaCO3). [ ]0% [ ]50% [ ]90% 7.Under the full impact of PETM, the ocean waters at those depths were approximately ________ saturated with CaCO3. This condition, brought on by the ocean’s absorption of carbon dioxide, lowered seawater pH (increased acidity) and caused widespread dissolution of seafloor carbonates. [ ]0% [ ]50% [ ]90%"
Explanation / Answer
Figure 2 depicts the PETM as a temperature spike of several Celsius degrees that took place approximately 56 million years before present.
From the discussion in item 2 above, it can be inferred that the oxygen isotope ratio (18O:16O) is a proxy for both temperature & glacial ice volume.
Examine the top graph in Figure 3. Isotopic studies of bottom-dwelling foraminifera fossils recovered from deep-sea sediment cores from sites described in the Figure 3 caption show that with the onset of PETM there was a rapid decrease in the carbon isotope ?13 value (note scale on left increases upward). This is indicative of a large increase in the concentration of the atmospheric greenhouse gases carbon dioxide (CO2) and methane (CH4).
5.The middle panel has scales for two different measures. Note that the oxygen isotope ?18 scale on the left increases downward, while the water temperature scale on the right increases upward. The middle panel shows that a relatively rapid decrease in oxygen isotope ?18 values was associated with a dramatic increase in seawater temperature of approximately 5 Celsius degrees.
6.The bottom panel in Figure 3 reports the percentage of calcium carbonate (CaCO3) in solution in seawater compared to the amount if the liquid were saturated with CaCO3. The shows that during the period prior to and the period after the PETM event, ocean waters at the two depths measured (4.8 km and 2.6 km) were approximately 90% saturated with calcium carbonate (CaCO3).
7.Under the full impact of PETM, the ocean waters at those depths were approximately 0% saturated with CaCO3. This condition, brought on by the ocean’s absorption of carbon dioxide, lowered seawater pH (increased acidity) and caused widespread dissolution of seafloor carbonates.
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