This is the third and final part of Sev’s documentation of the daily process of a foram paleontologist on board the JR. In this blog you can see a little of what he sees as we begin to understand what the cores can tell us.
We completed the first Site, Umnak Plateau, a little over two weeks ago. When we finished coring all drilling equipment was packed away and we started our transit to Bowers Ridge. The 2 day trip was welcome, but did not consist of rest as it was to culminate in presentations from all groups on our results. Serious analysis and synthesis was now a priority, as there would be no time for further work when we hit Bowers Ridge and started all over again.
Several Excel spreadsheets of data needed to be understood and, with the overwhelming number of species, obvious patterns were not forthcoming. All of us spent many hours plotting graphs and grouping and re-plotting, trying to gain some kind of understanding about overall trends in our data. As no one had ever drilled this deep here before, nothing was easy. To make it worse, the data we had collected was not as meticulous as it would have been on land with no time constraints, so there was always something in the back of my mind suspecting there might be no pattern.
The key to the foram data was to be found in a study of the Sea of Okhotsk.
As mentioned before, foram data can give an idea of oxygen and nutrient levels in the deep sea. A great study by Natalia Bubenshchikova and co-workers of living forams in the Sea of Okhotsk clearly showed that certain species liked lower oxygen than others, and most of the species living in the Okhotsk Sea were present in our samples. After grouping the species based on this characteristic, it was possible to get an overall estimation of how oxygen had changed over the last 800 thousand years. But what could have caused these fluctuations?
To find the answer we needed to pair our results with those of the other scientists. Without going into specifics, since that will all come out when the results of our expedition are published, we plotted the foram data on top of the other scientists’ data, and eureka, the match was pretty much perfect and the last few weeks of hard work were worth it. It was a little like walking on air. We were thrilled with our results and seeing something for the first time was pretty special.
The new discovery may shed new light on the last few interglacials, even though it appears that the pattern eventually breaks down as we go back in time. This in and of itself shows us that significant changes to the Bering Sea oceanography must have taken place many hundreds of thousands of years ago.
It is hard to not get really excited about seeing these things come together out here. Unfortunately to see the big picture we’ll have to wait until all of the scientists have a chance to give their input. But thanks to the IODP, it is coming together. Fascinating! – Doug LaVigne, Teacher at Sea