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A group of dolphins came to ride the bow of the ship; they put on a show for us. They were northern right whale dolphins (Lissodelphinus borealis). They are not whales but are named after the right whale because, like that whale, they lack a dorsal fin.
Gernot’s corner. |
As I started writing this update, I mentioned it was day 3. We all thought to ourselves, "Only day 3." It seems like we have been out here much longer, working day and night. We are accumulating enough data to make analysis interesting. The plot shows vertical profiles of oxygen from the first three stations (see right below). The continuous line is from an instrument on the CTD. The dots are from samples collected from water bottles. The bottle data comes courtesy of Gernot Friederich. He is very happy to see this long stretch without stations because he will be able catch up on his samples and sleep. Oxygen is produced by phytoplankton and consumed by bacteria and animals. As a result, it is higher close to the surface, decreases with depth, but then increases again. The deep increase is related to lower temperatures (higher oxygen solubility) and lower respiration by bacteria and animals. The oxygen minimum zone is a characteristic of most of the ocean and can have profound effects on marine animals. In the warmer waters of the northeastern tropical Pacific, the rates of respiration are higher and oxygen reaches very low levels. The levels are so low that bacteria respire nitrate. Once again, our undercurrent brings interesting chemical conditions poleward from the tropics to California. We expect to see the oxygen minimum zone broaden and come closer to the surface as we move towards the tip of Baja. Our biggest worry is now time. We are several hours behind schedule, and unless we catch up, we will have to start making some trade-offs. We can either go faster, skip stations, or come in later (Shhh—don’t tell the crew!). Decisions, decisions. Can’t tell what we are having for dinner, and the cook is sleeping. Have not skipped any meals, so I better go and get on the stair master. Oxygen data from M2, undercurrent 1 |