Paleocene-Eocene Thermal Maximum (PETM)

1. Paleocene-Eocene Thermal Maximum (PETM)  [Climate History from Deep Sea Sediments]

2. How can we use deep sea sediment samples to determine the effects of climate change, and how can we use that data to draw conclusions about the present?

3. What is PETM? Holocene (Anthropocene) = 12,000 y.a. to present • After the great comet [K-T Boundry] there was PETM… • Paleocene–Eocene Thermal Maximum • Occurred roughly 56 mya • Associated with rapid global warming • Major changes in the amount of  green-house gasses • Profound changes in ecosystems • Eocene Optimum PETM 55.8 m.y.a

4. Climate Change • Ocean Temperatures rise between 6 to 9°C in 20,000 years. • Evaporation • Sea level rise • Change in the oceanic circulation Patterns Point of Interest

5. Increasing Carbon • Entire exogenic carbon cycle (i.e. the carbon contained within the oceans and atmosphere) increased • Causes? • Volcanic Activity • Comets • Burning of Peat • Orbital Forcing • Methane Release • So, how do we know PETM happened?

6. Research • Used • Virtual Ocean • ‘CHRONOS’ data portal • Integrated Ocean Drilling Project (IODP) database

7. Task • Examine ocean core records from that time period for changes in planktonic foraminifera: Acarinina p. and Morozovella v. • These planktonic species continuously fall to the ocean floor, and are preserved as fossils in the accumulating sediment. • These species of planktonic foraminifera favor a warmer, more saline ocean. Thus, if the changes experienced at the PETM were global, you should find them distributed more broadly than in the tropics.

8. Hypothesis There will be a broader distribution of the foraminifera after the recorded PETM period, when compared to the time period before PETM.

9. ANTARCTICA LEGEND

10. ADP vs. AVS Jump in AVS Line of interest ADP

11. Foraminifera • Morozovella v. (blue dots), are farther south than the sub tropical regions, their usual habitat. The divergence of the foraminifera shows the divergence of warm waters from the equator. • Acarinina p. (red dots) are present in the the Southern Ocean (off of Anarctica), a region that mostly remains cold. This change proves that Antarctica at one point was hot enough to allow these foraminifera to exist.

12. Consequences • Profound changes in the environment (esp. deep sea) • Acidification (“souring”) of the oceans • Anoxia = mass extinction of 35-50% of benthic foraminifera over the course of ~1,000 years - the group suffering more than during the dinosaur-slaying K-T extinction + planktonic organisms diversified + numerous modern mammalian orders emerged due to amiable conditions.

13. Afterword • The most likely method of recovery invokes an increase in biological productivity, transporting carbon to the deep ocean. This would be assisted by higher global temperatures and CO2 levels, as well as an increased nutrient supply (which would result from higher continental weathering due to higher temperatures and rainfall; volcanics may have provided further nutrients). • Diversifications suggest that productivity increased in near-shore environments, which would have been warm and fertilized by run-off - outweighing the reduction in productivity in the deep oceans. • As humankind continues to add CO2 and other greenhouse gases to the atmosphere, we are contributing to the possibility of tipping the climate to one that is dramatically different from anything our species has ever experienced. Many ask: What changes will this new climate state trigger and how will the Earth systems respond?

14. Conclusion As humankind continues to add CO2 and other greenhouse gases to the atmosphere, we are contributing to the possibility of tipping the climate to one that is dramatically different from anything our species has ever experienced. Many ask: Are we close to reaching the point of no return? What changes will this new climate state trigger on human existence and how will the Earth systems respond?