Wednesday, July 1, 2009
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
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.
USF St. Petersburg
Wednesday, November 5, 2008
Today has been a very productive day aboard the Pelican. We completed our westernmost transect today and have begun steaming east with plans to sample a few more coastal sites before making our way back to Cocodrie, LA, on Friday morning.
Many scientists onboard analyze their samples as they are collected. Now that the cruise is winding down, we are beginning to compare our data and speculate about their implications. Radium isotope data collected by Jim Krest's group from USF St. Pete has revealed that, in addition to the Radium supplied to the region by the ocean and by the rivers, there are additional sources of the isotopes being supplied to the region. The excess Radium may be a result of groundwater input, offshore oil and gas production, and/or resuspension of the sediment on the seafloor by dredging, shrimp trawling, etc. Also, Wei-Jen from the University of Georgia, has determined that dissolved inorganic carbon (DIC) concentrations from the Mississippi River are more elevated that those from the Atchafalaya River. The implications of these results are still being explored, and collaboration among the scientists will continue throughout the coming months.
The weather continues to be warm and sunny with calm seas and magnificent sunsets.
Tuesday, November 4, 2008
092° 55.87' W longitude
We are on the westernmost transect of the research cruise, and have just finished the last station for the night. We expect a fresh start early tomorrow so that we can finish this transect and move on to some other sites as we head back to the Pelican's home port in Cocodrie, LA.
In the meantime, everyone is busy processing samples from the day's efforts to free up space for tomorrow. For the radium samples, our counting equipment has been going non-stop, and we have the lab bench lined with samples waiting to be counted. Plus, we still have seven barrels processing on the back deck which will have to be counted as well. So, at least for the crew from USF, there won't be much rest tonight. With less than three days left of the cruise, we will be doing all we can to collect samples from as many stations as possible.
But, it's not all work and no play. In between stations we have had a lot of fun, enjoying the beautiful weather and getting to know each other. Joining us on this second cruise is Caroline Coker, a science teacher for the Mobile County Public School System in Mobile, Alabama.
Caroline has been a great help with sample collection, and we've even got her helping to process some of the samples for Total suspended solids (TSS) and dissolved radon. So far, Caroline has helped to collect 2 box cores, and obviously doesn't mind getting dirty.
Also joining us is Iuri Herzfeld, a PhD candidate at the University of Hawaii, Department of Oceanography. Iuri is working on finishing up his dissertation at UH, but is interested in gaining a variety of oceanographic experience along the way. Most of his research has been from small boats (and he has even taken water samples from coral reef systems in Hawaii using personal water craft), so he was excited to come along on the Pelican. He, too, has been a great help with the sample collection and processing, and he managed to learn the procedures in record time. He is also a master of disguise...
(Hold mouse over image for Iuri's quick change)
(you may have to be patient if you have a slow connection)
But this is also a time to enjoy the sea and sky. Today the weather is nearly perfect: warm and sunny with little breeze and there are low puffy clouds in the sky. We are far enough away from the coast that the water is blue, as one classically thinks of the sea. But along this coast one also finds brown water, laden with suspended sediments from the river. And, between the brown and the blue, there is green water, colored by the microscopic plants that thrive on the nutrients from the river, but which need to wait for the brown sediments to settle out and allow life-giving light to penetrate the water. It is the plant productivity of these green waters that provides organic matter (i.e., “food”) to bottom waters on the shelf, thereby increasing respiration and driving the oxygen depletion that is problem here during the spring and summer.
One thing that is in short supply aboard ship is silence, or even quiet. The ship is essentially a big diesel power plant, so it is noisy most everywhere. On the Pelican, you can find relative quiet on the bridge as well as outside on the bow or forward areas of the fo’c’sle or 01 deck (the deck above the main deck). The only time I’ve come across silence at sea was accidentally. Several of us were on a zodiac in the North Atlantic south of Greenland. We had headed away from our noisy research ship in order to collect uncontaminated water samples when the outboard motor on the zodiac quit. Suddenly we were silent, rolling on five-foot ocean swell. We were not actually in any danger, so this was a rare and sublime chance to enjoy the sea estranged from human sound.
Monday, November 3, 2008
Saturday, November 1, 2008
Ah, but the food doesn’t stop with the meals! Always on the table in the galley are containers of candy and cookies, a bowl of trail mix, and fresh fruit in case you decide you want to be healthful. Of course, if the candy and cookies aren’t enough for you, there is a freezer full of ice cream that you are always welcome to invade. In fact, you can pretty much eat anything that’s available.
Now this plethora of food might sound like paradise at sea, but it’s a problem. In the waiting time between stations, the galley is the main place aboard ship that people can gather. So, one sits there in the waiting boredom amidst temptation. The vast selection at mealtime doesn’t really provide one with choice: since the food is all good, one wants to sample it all. Many people also find that the slow rolling motion of the ship tends to make them a little tired and hence they lose what little remaining self-control they had.
The marine tech aboard ship tells me that he has gained 20 lbs on long deployments (only to lose it on spending extended time at home). The more fit looking crew tend to take one moderate plate of food and immediately leave the galley. I had a friend who once confessed to gaining 36 lbs on a 36-day cruise. And, for those of you tempted to just increase your level of exercise, remember there’s no place to jog aboard ship and no exercise room either (at least on modest sized ships like the Pelican).
So, what’s a poor boy like me (with loss of self-control) to do? One strategy (following that of the more fit crew), is to avoid the galley....but as chief scientist, I shouldn’t go into hiding. Another is to skip a meal (but then there are those ever-present snacks calling my name). You can also invent a special diet for yourself. For instance, one can readily become a quasi-vegetarian. I say quasi because, although the cook would certainly oblige a vegetarian or any other special diet, no one on this cruise has requested such a consideration. And, I don’t care to ask the cook for special food preparation on his part just because I’ve lost control.
Well, it’s almost dinner time. So, I’ll just go contemplate this problem in the galley. It’s a rough life.