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From Macro to MicroAugust 14, 2012

On the helideck at 12am, we kicked off the night shift gazing deep into enveloping darkness, eyes keenly tuned to shooting stars. Yesterday morning was the Perseid meteor shower. Beyond the lighted derrick, and above a thin veneer of fog, the sky revealed a pristine clarity. While the early hours afforded us a few spectacular meteor sightings, the tireless heavy morning fog steadily settled in.

We retreated to the lab where the scientists anxiously continue preparation for the long-anticipated arrival of the first ocean sediments. For some the research has yet to begin, for me it already has. This site has been drilled once before - during the CK06-06 Shakedown Cruise in 2006. The first approximately 600 meters of ocean floor were drilled then, but only the upper 350 meters recovered - that’s what I’m looking at.

My specialty is micropaleontology. I am particularly interested in diatoms (single-celled siliceous phytoplankton) and calcareous nannofossils (single-celled calcareous phytoplankton), the biostratigraphic records of which apply precise geological ages to ocean sediments. They are both exceedingly useful for telling the story of paleoenvironmental shifts within the oceans, as well.

Thalassiosira oestrupii is a marine diatom and marker species used to date sediments up to 5.5 millions years old.

What takes hundreds of meters of drilling pipe to recover requires hundreds of times of magnification to identify. A trained eye and patience goes a long way in this sport, too! Within the upper 350 meters, I am working to refine the existing age model of oceanic sediments at this site based on particular species called “marker species”.

A polarizing microscope prepared to observe diatoms and calcareous nannofossils prepared from drilled sediments.

The first and last appearances of these so-called “marker species” must correlate across vast regions, if not globally, in order to be reliable markers of time. They tend also to be common in their occurrence and distinctive in appearance. Alongside with geologic time, I will look more closely at entire assemblages of these microfossils to articulate the paleoenvironments that supported them - after all, history repeats itself and if we know where we came from, we can see where we are headed.

The necessary "macro" for retrieving ocean sediments.

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