Recently, I’ve been lucky enough to take part in Dr. Nancy Rabalais’ annual mapping of the hypoxic zone in the Gulf of Mexico. Dr. Rabalais has led this cruise for the past 31 years, and has graciously allowed me onboard the R/V Pelican for my first research cruise. This cruise set out July 31st and returned on August 1st.
My primary role was to collect surface water at each site that will be used by the Rabalais Lab for water nutrient and suspended sediment data. This consisted of throwing the infamous bucket overboard:
While onboard, I also was able to collect some samples for the Thrash Lab. I sampled from stations nearshore on transects that extended outward from our Board of Regents coastal sites that we have been visiting for the past few years (check out Henson et al. 2016 for more info). I collected surface water via the CTD from sites of interest and used a peristaltic pump to size fraction the water through 2.7um and 0.2um filters. These filters will be used to study the community composition of sites offshore in relation to the three year data that we already have from our coastal sites.
The first day of the cruise was a bumpy ride, and I was a little seasick despite the motion sickness medicine. Gladly, the waves soon settled, and the rest of the cruise was smooth sailing! I was on the night shift (7pm-7am), which meant that we got to see all of the cool fauna! The floodlight that followed the CTD into the water was a beacon for sealife, and we saw jellyfish, eels, squid, dolphins, crabs, and fish off all kinds. The fauna actually became an indicator of the dissolved oxygen in the bottom waters. Often when we found crabs and eels swimming on the surface, the bottom waters had very low oxygen levels or were virtually anoxic. While we waited for the CTD to come back onboard, we sometimes netted some Sargassum to see what kind of critters were living there.
One of my favorite parts about the trip was the spectacular views of the sky. At night on the shelf, the only lights come from oil rigs. Sometimes we were quite close to these rigs…