After some initial technical glitches, we have finally set sail. We left Fremantle on Wednesday, November 7, at 1600 hrs (local time). Since then we have stopped at three stations to collect seawater and mud from the ocean bottom. We arrived at our first sampling station in the middle of the night. Starry sky, cold air and sloshing waves were all there to welcome us. Before I tell you all about how we collect samples in the middle of this huge blue, let me quickly describe the mission of this cruise.
The main objective of this cruise is to collect mud from the ocean bottom. This mud, or sediment as we call them, can be as old as millions of years; although the mud that we intend to collect on this cruise will not be that old. Scientists look for single cell organisms called foraminifera in this mud among many other things. Foraminifera shells are made up of calcium carbonate (chalk), and have a unique ability of storing past climate information in their shells. While I do work with these organisms, I am interested in studying ocean chemistry for this particular project. So besides collecting mud, we will also be collecting seawater at different depths.
Ocean can be as deep as 5000 meter (~3.1 miles) at places; so how do we collect water that deep? Scientists use an instrument called Conductivity, Temperature, Depth (CTD), which sends us information about the water properties (such as temperature, salinity) as it goes down to the ocean bottom. Also attached to this instrument is a set of bottles that can be closed from the ship's control room at specific depths. The moment we close a bottle, it captures the water at that particular depth. Where and why we want to close a bottle is something we determine based on the information that CTD sends us while going down to the bottom. Once up on deck, we collect water samples from these bottles 'fired' at the depths of our interest.
Yingzhe Wu, a postdoctoral researcher from Columbia University's Lamont-Doherty Earth Observatory (LDEO) is one of the participating scientists on this cruise, and we are working together on the ocean chemistry component of this project. We both had been a bit seasick since we left the port, but I think we are over it now (or I want to believe so). Since samples are coming up at a very fast pace, we are up for 18-20 hrs at a stretch so that we can process these samples and get ready for the next set of samples to be collected. I have already lost track of what day of the week it is. But we are ready for more samples in the coming days and weeks. May the Ocean Goddess/God be with us!!