June 16th, 2021
Today begins the end of the cruise. After spending three and a half weeks at sea, we returned to our final site, Mississippi Canyon. We launched our final Jason dive around 8 in the morning, after scrambling to finish cups to shrink. We placed our final deployments in Jason’s basket and saluted Jason as it was picked up by the winch and released into the water. At 1074 meters deep, Mississippi Canyon represents our midwater site compared to the shallow trifecta sites, and the deep Florida Escarpment site.
When we reached the bottom, we were met with a deserted landscape. It felt like an alien planet. With mud volcanoes and small canyons, the occasional fish or patch of bacterial mat, it was an unfamiliar habitat. We trekked through this wet desert scanning for our target mussels, with this site containing two different kinds: Bathymodiolus childressi and Bathymodiolus brooksi. We want to collect both kinds to understand the differences between the species. They look fairly similar, while brooksi has a chalkier texture and a bump on the umbo (the hinge of the mussel), so we had to look carefully. While we searched for mussels, Dr. Young set up an early Father’s Day present by preparing a Zoom with his dad to livestream the main science camera we use during our dives. Deep-sea habitats are bizarre, and we try to share the exploration with those we can, like this blog attempts to.
Here’s a video that Avery Calhoun created on the last research cruise highlighting the Mississippi Canyon site:
During the dive we did struggle to find our mussels, these deep-sea sites aren’t entirely understood or predictable. Luckily, we knew of another potential location from another deep-sea cruise and headed that way after scanning our original site. We traveled northwest and eventually found a large mussel bed where we collected our specimens, finding both of the target species, and deployed our equipment. After completing those objectives, we had the task of recovering our equipment from the last cruise, which was a ways away. On the last cruise the dive was cut short due to weather and the equipment was not an optimal location. On the way back we stumbled across a natural wonder, a brine river! We’ve seen a few brine pools, and a lot of brine puddles, but this river of brine extended across our whole view from the van. After crossing the salty stream, we picked up our equipment and resurfaced. With Jason back on deck, and with heavy hearts, we began sorting our samples for the last time.
As our time comes to an end in the Gulf, it’s been interesting to see a new perspective on human activity. When we look around, we are surrounded by oil rigs. With the oil that is seeping out at our research sites, the number of rigs was not surprising. However, as we move from site to site, there’s always a few oil rigs on the horizon. At night they come alive, and the horizon is dotted with these small cities on the water. Even the open ocean is still bustling with activity.
Tonight, we deploy Sentry for the last time. As we sort through the final samples, sort the last mussels, and take our final morphotype pictures, we’re getting ready to start packing up and heading home.