Monday June 24, 2013
Greetings from the middle of the Gulf of Mexico. We arrived at our first site, Station 3, midday yesterday and immediately began collecting. First up, we dropped a Z-shaped trap to collect large animal specimen from the deep-sea (depth ~1100 m). We plan to pick this trap up later tonight (after wrapping up our work at Station 1), and will find out then if we picked up any monsters from the deep.
After the trap was dropped, we deployed our 24-cannister CTD (a conductivity, temperature, and depth) sensor, which took measurements at every 100 m.
Then onto the box cores!
Box cores collect a large square portion of sediment. A group from LSU, led by Bob Carney, was sieving through these samples in hopes of finding animals, such as tube worms, sea cucumbers, and small arthropods.
What was really exciting about these box cores is that it gave us a snapshot of the surface of the seafloor.
See? It’s not just mud and oil down there!
And last, but definitely not least, the multi-core sampler, shown below.
This is the main event and why Shelby and I are here. The multicore sampler is deployed into the sediment and collects one continuous core of sediment roughly 40-50 cm deep, including water (and any critters) just above the seafloor.
One of the greatest parts of seeing these cores come up (other than seeing a giant piece of equipment deployed to the seafloor and retrieved with cores from 1100 meters below the surface) was the visual separation of the oxic and anoxic layers. The oxic one seen on top is a thin, red-brown silty layer, whereas the anoxic layer is the blue-gray bottom layer, which has a clay-like consistency. The newer layer is found ontop, but even so, sediment settles very slowly. We are most interested in the top few centimeters of sediment, for it will give a snapshot of sediment-forming activity in the Gulf over the past few years. For our core, we sliced it using aluminum sheets, packaged the sediment into glass jars, and froze them onboard for further examination.
In the early morning (around 4am), we arrived at Station 2, but both of us were asleep during that stop (although we did wake up in time to package our own core).
Shortly after that, we were making way to Station 1, home of the Macondo Well. This site is where the wellhead blew up a few years back, and the site of interest for our research.
Sarah and Shelby