[Climate History from Deep Sea

Sediments]

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?

What is PETM?After the great comet [K-T Boundry] there was PETM…Paleocene–Eocene Thermal Maximum

Occurred roughly 56 myaAssociated with rapid global warmingMajor changes in the amount of green-house gassesProfound changes in ecosystems Eocene Optimum

Holocene (Anthropocene)

= 12,000 y.a. to present

PETM55.8 m.y.a

Climate ChangeOcean Temperatures rise between 6 to 9°C in

20,000 years.EvaporationSea level riseChange in the oceanic circulation Patterns

Point of Interest

Increasing Carbon

ResearchUsed

Virtual Ocean‘CHRONOS’ data portalIntegrated Ocean Drilling Project (IODP)

database

TaskExamine 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.

HypothesisThere will be a broader distribution of the

foraminifera after the recorded PETM period, when compared to the time period before PETM.

ANTARCTICA

LEGEND

ADP vs. AVS

Line of interest

Jump inAVS

ADP

Foraminifera

ConsequencesProfound changes in the environment (esp. deep

sea)Acidification (“souring”) of the oceansAnoxia

= 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.

AfterwordThe 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?

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?