2003 Marley B. Bice
Outstanding Marine Science Project Falmouth High School Science Fair
National Ocean Science Bowl (NOSB)
6th Annual Blue Lobster Bowl
March 7-8, 2003
Falmouth High School Science Fair, Falmouth, MA
Outstanding Project in the Marine Sciences Recipient Marley B. Bice
Do the Oxygen Isotopes of Foraminifera Record Temperature?
The objective of this project was to examine how well the temperatures
inferred from the oxygen isotope ratios (d18O) in the skeletons
of different species of planktonic foraminifera record the temperature
of the water in which the forams grew. Scientists studying future climate
change use d18O in forams from sea floor
sediments to understand past climate change. But the isotopic temperature
record and month of bloom of different planktonic species is not well
The study area is in the North Atlantic Ocean, near 40°N, 70°W.
The samples were collected in 1981-82 and were stored in buffered solutions.
I sieved the solutions and extractedcarbonate skeletons of several different
species of planktonic foraminifera. d18O
was measured on a mass spectrometer at Woods Hole Oceanographic Institution.
Based on salinity, I estimated the d18O
value of the water for this area and calculated temperatures using a published
equilibrium equation. I compared the resulting temperatures to oceanographic
measurements made by others in this area of the Atlantic. The results
show that the species Globigerina ruber pink and G. sacculifer
are generally good recorders of sea surface temperature. On the other
hand, G. inflata records winter surface temperature but then
tends to live in deeper, colder water during the summer months. I found
that some samples had been poorly buffered while in storage so that the
low pH in these samples dissolved forams. This meant that I was not able
to reconstruct a full year’s temperature cycle. The data I did get
show that the foram d18O records temperature
and that G. ruber pink and G. sacculifer would be the
best to use in reconstructing past sea surface temperatures.
Last updated: March 4, 2010