FINDING NEO

Ocean Record of Ancient Climate Foraminifera (“Forams”) One-celled organisms Widespread through the oceans “Tests” = shells Approximately the size of sand grains Made of CaCO3 or sediment particles Fossil tests preserved in ocean sediment layers Many modern species have existed for millions of years – scientists can study these “proxies” today! Some forams make their tests from sediment particles; a great percentage of forams have CaCO3 tests.

Living Forams The living organism’s projections - Rhizopodia – for locomotion or gathering food. The tests are the dark objects in the center, and the radiating white features are the Rhizopodia. Video credit: from A Foram’s Tale, SCOR – International Council for Science, Scientific Committee on Ocean Research – ScienceMediaNL http://www.youtube.com/watch?v=xfZ_9UWcAB8 Photos: Howard Spero, UC-Davis Photo Credits: Dr. Howard Spero, University of California – Davis Video: International Council for Science, Scientific Committee on Ocean Research - ScienceMediaNL

Photo Credits: Michael Hesemann, Foraminifera EU Fossil Foram Tests The many holes in the tests are where the rhizopodia used to stick out. Fossil foram photo credit: Foraminifera.eu, Michael Hesemann, http://www.foraminifera.eu/ Creative Commons Attribution-Noncommercial-NoDeriv 3.0 Germany, http://creativecommons.org/licenses/by-nc-nd/3.0/de/deed.en Photo Credits: Michael Hesemann, Foraminifera EU

Neogloboquadrina pachyderma aka “N. pachy” or “Neo” HOW TO DETERMINE COILING DIRECTION: The “coil” direction can be determined in this orientation of the test. With the test oriented so that the largest “blob”, i.e., chamber is at the top of the field of view, a curved line is drawn to connect all the chambers from largest to smallest, as shown. For a Neo that coils to the right, the curved line appears to make the letter C. If the curved line makes a “backward C”, the coiling is to the left. Students commonly ask “what happens if you flip the test over” - on the “opposite side” of an actual Neo test, it has a very different appearance, with a large aperture visible, and the coiling direction would be traced differently in that orientation. right coil = warm ocean water left coil = cold ocean water

We can use fossil “Neo” tests (shells) to find ancient ocean temperatures OLDER High Percent Right Coil = Warm Ocean YOUNGER Low Percent Right Coil (Mostly Left Coil) = Cold Ocean The forams can be analyzed from samples of ocean floor sediment layers, recovered in a core. The oldest layer is on the bottom, and the layers are progressively younger upward (Principle of Superposition). If the forams are separated from each sediment layer in the core, they can be analyzed for their relative proportions of left and right coiling Neos. The higher the percentage of right-coiling Neos, the warmer the ocean temperature at the time that sediment layer was deposited.

These photos illustrate the coring from shipboard: Upper left: coring device for 6 piston cores in lowered by cable to the ocean floor, and a lever or button release triigers the piston to push the corers into the ocean floor sediment; upper right: scientists carrying a recovered core from the coring device to the shipboard lab; bottom: labelling the core in the lab. Photos: Texas A & M University, College Station (Ocean Drilling Program); http://www-odp.tamu.edu/publications/copyright.html Photo Credits: Texas A & M University, College Station (Ocean Drilling Program)

Finding “Neo” Ocean sediment core

USE “NEO” TO FIND THE CLIMATE HISTORY OCEAN SEDIMENT CORE SOUTHEAST OF NEW ZEALAND Layer 1 10,000 ybp Layer 2 15,000 ybp Layer 3 20,000 ybp Students will be analyzing Neogloboquadrina forams from three sediment layers in the core from the ocean floor.. Each person in a 3-person team will analyze the “Neos” from one layer, and then the team will combine all their results and analyze the climate trend over the time interval from 20,000 to 10,000 years ago. If you have constructed a model of the sediment core, show it to the students at this point. ybp = years before present

Neogloboquadrina R L right coil = warm ocean water Directions to students: you will have a sheet with a “microscope view of the forams from your sample. Using the overhead marker pens, remember to orient each foram so that the largest chamber is “up”, and draw a line connecting the largest chamber to progressively smaller & smaller chambers. To help keep track of the coiling when you count the forams, as soon as you determine the coiling direction MARK AN “R” OR AN “L” NEXT TO THE FORAM. right coil = warm ocean water left coil = cold ocean water

Unless you are good at upside down visualizations, you will need to turn the paper (“rotate the microscope stage”) so that you always orient a foram with the large chamber at “up”. The two forams shown are in the correct orientation to determine coiling, but … (next slide) R L

L R R R … but you’ll need to rotate the paper to determine coiling for these 4 forams.