Tuesday, May 6, 2008

Busy, busy, busy

It seems like we try to do a little more science every day. Recently, we started taking grab samples of the sediments at each station, using a Ponar sampler. This is a very quick and easy way to get a sample of the bottom sediments, but it does not go very deep, and the sediments can get mixed up because of the way the sampler works.
The Ponar goes down on a cable , and when it hits the bottom, it releases a pin. Then, when the cable pulls back up, the jaws of the Ponar close and scoop up the mud. We will do some analyses of the sediments when we get back to the lab. Here's a quick video of the Ponar coming back on deck, just before we open it up to check the sediments. At this station, the sediments were very thick, about the same consistency as modeling clay. Leslie loves to dig into the mud to see what we got!



There was a question about how we get our food. We rely on Randy, the ship's cook! He's awesome! Randy trained as a chef at a culinary institute in New Orleans, and he used to work on private yachts. Randy has worked on the Pelican for a little over a year. We are all curious to know what kind of magic he could do if his stove, oven, and grill did not roll all over the place! Here he is, grilling some food for dinner on one of our calmer days.

Sam is one of the crew on the Pelican. His title is the Assistant Engineer, but he does a little of everything out here. He works from 6pm to 6am, and during his "watch" he is responsible for making sure everyone is safe. He runs the winches to deploy all the gear, and he helps out all around the boat. Here he is, getting ready to fillet some of the fish that have been caught over the last few nights. During the night, the Pelican often travels long distances between sampling stations while the scientists take a break to get some rest. If we get to the next station early, we often tie up the Pelican to old oil rigs, and if anyone has the energy they can fish for a little while.

5 comments:

Anonymous said...

Is it correct that you collected sediment samples only from the surface of the sediment layer?

Yummy red fish to grill...

Bob

Jim Krest said...

Bob,

The Ponar sampler only goes down about 4 to 5 inches into the sediment, so yes, just the surface of the sediment layer is sampled. We can deploy and retrieve it in 5 to 10 minutes for a quick look at the topmost sediments.

The box core sampler penetrates up to about 2 feet (1.5 meters), but it is more cumbersome, and we need to interrupt the trace-metal water sampling to deploy it, so we don't use it as often.

All of the fish in the picture are Red Snapper. On some of the oil rigs, we can catch them almost as fast as we can get the bait to the bottom. Really fun fishing. We had some last night for dinner, and they were, indeed, quite yummy.

Jim Krest said...

Tom Krest (Jim's older brother) sent us some question by email:

Hey This looks so cool with the ponar sampling that you are doing. How deep's the water, how many samples are you taking? How large a sample do you need? Good luck.
Tom Krest

Blog: Mississippi-Atchafalaya-Gulf Mixing Cruise
Post: Busy, busy, busy
Link: http://mag-mix.blogspot.com/2008/05/busy-busy-busy.html


Hi Tom! It's great to hear from you.

(I'm really not used to having email while out at sea, so it's nice to be able to chat with family. In the past, I've gone up to 6 weeks on research trips with little to no communication, so this is pretty cool!)

To answer your questions, we've been staying in relatively shallow water. Our deepest station was in about 100 meters of water (a little over 300 feet). This is the edge of the continental shelf, and the water depths drop off very quickly if we go past this depth, as deep as 1000 meters or more in some of the underwater canyons.

So far, we have over 100 water samples, 4 box cores and 10 sediment grab samples with the ponar.

For the water samples, we take anywhere from 20 liters (5 gallons) to 440 liters (~110 gallons), and we process them on board so that we don't have to bring the water back (for more detail, check out our main website: http://www.stpt.usf.edu/coas/espg/magmix/home.asp )

Say Hi to Janet and the kids!

-Jim Krest

Tom said...

Hey you all it looks pretty interesting out there. How many samples do you need to take at each site you stop at? How deep is the water usually when you are taking your samples. Do you get anything other than (crabs) such as garbage or debree from storms? Sent this blog page to Pal-Mac Middle School in NY to the science teachers also. Good luck with your testing!!!!!

Anonymous said...

What a great catch! Looks like you folks are eating well!
I'm really enjoying the videos. They really do a nice job of showing how samples are collected.
I'm glad to hear that you've been able to collect so many water and sediment samples - sounds like you all are having productive field season!
- Melanie