September 6, 2012
Here is what the normal ocean looks like.
Now once we got close to the mouth of the Amazon River, things changed drastically.
Above and below: We are about 100 miles from the mouth of the river.
Below: We are about 12 miles out and things got crazy! So much sediment in the water it was completely brown! The ocean was brown!!
Below: We thought it resembled coffee with some milk in it.
Below: Now you see the CTD….
…Now you don’t.
Below: People were pretty pumped
Below: This water was seriously difficult to process and work with. I don’t even know if you could call it water.
Below: The salinity was .05. That is unbelievable! In the ocean!!!!
All and all, it was pretty amazing. Hope you agree.
September 5, 2012
We were walking around Barbados at night and we came across this kebab shop and I lost it. One of the funniest business signs I have ever seen. I personally think these places are gross but I would consider going in with a name like that! What a name! And why I like twice? Probably should not question genius.
I am not always the best at cleaning up after myself in a timely fashion. On a cruise I am usually doing multiple things at once, when I finish them all, I clean it up. Not always the best way of doing things but I don’t always have a choice. Well one day when I went back to clean up the equipment I use to pick Tricho and set up my assay, the people in the area had done something with it. They had arranged it to spell out my name. It might not seem like much but at the time it was fun to come see. Not much going on on the boat.
I talk a lot about having/getting water to incubate and how we use a CTD but I thought it would be a good idea to show you what I mean.
Now the bottom 3 pictures show a big crane deploying the CTD. Its the metal thing hanging. This has 24 10 liter bottles on it that we can control when the open and close. It also has a bunch of sensors on it that can tell us things like what depth its at, temperature, salinity, how much light, etc. We can use these paramaters to decide where we want to get our water from and the just close a bottle and seal that water in. Now the CTD can come up and we have water from different discrete depths.
The top two pictures show the CTD in the water.
The top right shows a scientist and a crew member on board waiting for the CTD to come up so they can recover it. They use those hooks to get a hold of it and the rope to steady it as it is craned onto the boat.
Now as you all know, one of the main things I do on these cruises is measure nitrogen (N) fixation. I do this through the acetylene reduction assay where I add a substrate that tricks the enzymes involved in N fixation into thinking they are carrying out the process. This process is something that I can measure easily. They convert acetylene into ethylene and this change can be quantified on a gas chromatograph. I think that’s enough detail. As I have said earlier I take Tricho (if none of this seems familiar to any of you just look back at previous posts) and measure N fixation of these organisms alone. They are very abundant in the open ocean and can actually be seen with the naked eye so it is easy to isolate them for these kinds of measurements.
To the right we can see a net tow that I just finished. The net tow concentrates the things in the surface ocean and that is why it looks like this color. There are a ton of zooplankton that are mainly copepods, which are tiny animals that feed on the plankton. Below is a picture on one such copepod. From here I pick out the Tricho. Once I have them, I seal them in a bottle and the assay begins.
Once the assay is setup, I periodically take a subsample of the gas in the bottle the Tricho are in and measure an increase of ethylene gas over time. I use an equation to convert that into an amount of N fixation. On each side you can see me taking one such subsample. I am also decked out in some of my cruise gear.
Once the subsample is taken I inject the gas into the gas chromatograph and it is separate into each component of the gas.
I then sit back and wait about a minute for my results.
Finally I get a readout like this and I compare it to a standard. The first big peak is the ethylene that was converted and the second huge peak is the total acetylene I added. This can tell me how much, if any N is being fixed in real time. I got a lot of good results this cruise! Still need to process it all though. Going to take a lot of time.