Wednesday, July 1, 2009

Middle of 4th day update.

Here we are at about the midpoint of the research cruise. The weather has been incredible with mostly calm seas and almost no rain. Even on the one day it got a little breezy, everyone had their sea legs already and there were no reports of mal de mer.

As usual, we are taking lots and lots of water samples to characterize the continental shelf waters off the coast of Louisiana. This trip is particularly interesting because it has timed to coincide with the occurrence of a "dead zone" in this area almost every summer. The dead zone develops from a combination of processes; the strongest include 1) a thin layer of fresh water from the rivers which floats on top of the sea water and prevents oxygen from mixing in; 2) decreased mixing because of low winds this time of year, and 3) a process called "eutrophication" which occurs when plankton grow very rapidly when they have an abundance of food/nutrients. The growing plankton aren't the problem, themselves. The real problem is that they only live for a few days, so even as the plankton population is increasing, more and more of them are dying as well. When they die, they sink, and as they sink, other organisms (especially bacteria) break them down, recycling the nutrients. As they do so, they use up oxygen from the water column. And if the conditions are right, the dissolved oxygen concentration can drop low enough that fish and other critters can't get enough oxygen, and they either die or leave the area. On several stations, now, we have seen very low oxygen concentrations in the bottom water, meaning that we should be in for a pretty strong dead zone off the Mississippi River this summer.

This trip, I brought along three helpers from USF St. Petersburg. Alanna Lecher (who participated in the 1st cruise), Iuri Herzfeld (who participated in the second cruise) and Lisa Vlaming. Lisa is new to the lab, and I'm glad she could come along to get some experience. Check out their profiles on the USF website: MAG-Mix home

We have a busy schedule this trip. In addition to the water samples, we have an ambitious plan to get lots of mud samples to analyze the sediments and the pore water. We've done a few cores on the past trips, but we're hoping to get really good coverage of the study area.

I'm having trouble uploading images (sorry), but may be able to post some on facebook

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Tuesday, June 30, 2009

Well into the third and final cruise of the MAG - Mix study

PHEW! Here we are, just finishing up the third day of the research cruise. I thought it would be an easy one, having two trips already under our belts, but we all need a little excitement, don't we?

For my group from the University of South Florida St. Petersburg, we got more than we bargained for before we even got to the boat. We started our drive to southern Louisiana last Friday, planning to stop in Mobile, Alabama, after 8 or 9 hours of travel. Just about an hour or so up the highway, though, we had a tire blowout on our trailer full of gear. No real harm done, but we could have skipped changing a tire in the Hot Florida sunshine, slapping away the fire ants. We limped into Gainesville, replaced the blown out tire, replaced the other one that looked a bit dry-rotted, and replaced the odd-sized rim. For good measure we got the oil changed (it was a bit overdue) and refueled at Sonny's Bar-B-Que.

The rest of the trip looked like it was going to be uneventful, but then the AC compresor seized up just past Pensacola. After it (and the belt) cooled down a bit, it seemed to have settled itself out, but we limped into Mobile a bit on edge, 12 hours after we started. At some point we realized a fuse had blown for the dash lights (and the running lights for the trailer), and when we stopped to refuel and get some fuses, the AC compressor made some very bad noises.

It was too late to get much done, but Iuri made some contacts at the restaurant which eventually led him to a mechanic who was kind enough to chat with us on the phone at 11:15 pm on a Friday night. Essentially, he advised us to get the car checked out in the morning before trying to continue. Fortunately we were able to get the car looked at Friday morning at 7:00 am. The mechanics bent over backwards to replace most of the AC system and got us back on the road by 11:00 am. We finally got to the Pelican about 4:30 in the afternoon and spent the rest of the evening getting everything loaded, organized and secured for a midnight departure. Yikes! Not how I like to start a trip, but everyone arrived safe and sound.

Many thanks go out to my wife, Robin, for tracking down lots of people on Saturday morning apprise them of the situation and to get authorization for the repair. Many thanks also go to Bob Wang, our laboratory manager, who came in on Saturday to make sure we could pay for the repairs.

I'll try to get more people to post on this blog soon. Our chief scientist, Alan Shiller, is maintaining a separate blog on his facebook page. Feel free to send him a friend request if you would like to read it.

Jim Krest
USF St. Petersburg