The geographic expansion of hypoxia along our westward transit continues. We had to go all the way to the most southern station of the I line, I9, before reaching a zone without bottom hypoxia. Today we are transiting back north along the J line and will reach K. In keeping with Nancy’s commitment to science communication, particularly with the lay public, she and Leslie are creating and maintaining a real-time map of bottom DO concentrations here. It’s fascinating to watch this develop. The vertical profiles that come off the CTD are the most exciting parts of the day, and we frequently make bets now as to how low the O2 will be and at what depth. Gene Turner usually wins the bets. He and Nancy have developed a sixth sense for the distribution of hypoxia after this many years of study.
It’s generally been a beautiful cruise. The full moon a few nights ago was breathtaking as it peaked in and out of the clouds. At night the oil platforms dot the horizon line like low-lying stars. The night shift has seen crabs at the surface, particularly in the areas of bottom hypoxia. There’s also a lot of Sargassum sea weed in the Gulf. I’m used to seeing it in the Sargasso Sea, but I had no idea it grew here. Of course a quick search shows that it grows all over the world and there are many different species. We’ve also seen dolphins, birds, fish and I noticed a giant comb jelly near some Sargassum yesterday afternoon.
A little down time for an update. We are in transit to the I line after finishing H this morning. We are continuing to find expanding bottom hypoxia as we move westward. Nancy and Leslie are creating maps of the hypoxia as we go. Lauren and I are sampling both inside and outside the hypoxic zones. We’re tag teaming on opposite shifts and doing between 6-8 stations per day.
No cruise goes off without a hitch. Crises overcome thus far: winch needing to be re-spooled, CTD switched off the original winch and then back, hydraulic line break (they use vegetable-based biodegradable hydraulic fluid on the Pelican- very cool), main floor drain clogging. But onward we go. The crew has done a great job responding to these issues.
Three more full sampling days to go. Seas are staying calm, 10-15 kt winds, it’s cloudy this morning. Looks like we’ll be back before Tropical Storm Dorian (the storm formerly known as tropical depression four) gets to the area, which is nice.
Oil platform at night.
The sound of a fiddle makes it feel like a proper ship
Watching the CTD feed
Finished the E line during the night. Still have calm seas and good weather. Keeping our eye on newly formed tropical depression four. Sampling the F line this morning. Noticing increased bottom hypoxia as we move west.
Made it through the C and D’ transects last night. Started on D this morning when the day shift came on. I’m on the 7am-7pm shift, which is nice. Crew had to re-tap our CTD and then re-spool an entire winch, at sea, yesterday. Unbelievably hard work. Good on ’em. The sea state has stayed mellow, and we’ve got nice sun today. Full moon last night was a sight. So are all the platforms everywhere. Sampling in the Gulf is a trip because of the ubiquitous oil platforms in our general area. Some of our stations are right next to them. And Nancy’s group even has real-time oxygen sensors mounted on a few at depth.
Every one of those little black dots on the bottom half of the screen is an oil platform.
We cruised through the night to the mouth of the Mississippi River, where we went up the southwest pass for a bit yesterday. The point was to get a salinity/nutrient profile so that we can accurately judge which phenomena we see in on the shelf are biological vs. due to dilution effects from the river plume. Then we proceeded to the A’ and A transects, which we finished during the night. Starting the B transect this morning. I’m on the 7am-7pm shift, which is nice. Sea state is very mellow. Overcast the last couple days with scattered showers, 2-4 ft swell. The Pelican is a nice ship. Good stability, good food! Not great internet. Check out the official shelf wide cruise blog, which also has a map of our sampling stations. I’ll try to give updates whenever we’re close enough to land for cellular data.
Today I leave on my first cruise as a new faculty at LSU. I’m joining Nancy Rabalais and collaborators of hers from the Louisiana Universities Marine Consortium (LUMCON), as well as a graduate student from Olivia Mason‘s lab at Florida State University (@OUMasonLab) to participate on this year’s shelfwide hypoxia investigation in the “dead zone” of the Northern Gulf of Mexico. Nancy and her colleagues have been studying this phenomenon for almost 30 years. I’ll post updates as we go (and hopefully add to the rest of this new site).