We Blogged It!
Lat/Long: 06.09N 050.57W
Air Temp:28.5C 83.3F
Surface Temp: 29.62C 85.32F
PITS calling home!
Around noon yesterday everyone was out on deck to see the deployment of three sediment traps( Particle Interceptor Traps-PITS). The sediment traps are one of three projects being conducted by Dr. Will Berelson and his team from USC (in Los Angeles). The traps are made up of 12 cylindrical tubes with funnels inside of them that capture particles in a cup attached to the bottom of the funnel. They are cast into the sea and connected to a buoy with a radio transmitter and floats that keep them at 150m below the ocean surface. They’ll stay in the water for about 2 days and then we’ll return to retrieve them. Will explains that they will give us a “snapshot” of what’s falling between the surface and the bottom of the ocean. When they’re retrieved, they will collect the particles and measure the flux (amount per unit area per time) of C, N, Si and provide samples for colleagues on board. They will also measure the Thorium content of the trap material. There is uranium in the sea, and through radioactive decay it changes to thorium, which sticks to the particles (detritus) that sink to the bottom of the ocean. Will is measuring how much thorium is missing from the surface water and how much has fallen into his traps. They should equal each other! At this writing, satellite buoys attached to the traps are sending signals back to the lab here on the ship, and we can track their location and movement.
However, Will’s primary project is sediment coring-capturing 30-50 cm of mud and extracting the pore water (water trapped in between the grains of mud). This process gives him a record of what has falling through the water column in the last 2-3 years, and the amount of carbon that has made it to the bottom of the ocean which subsequently degrades. He can also get a measurement of the amount of opal that falls to the seafloor. Opal is a glass (SlO2) that diatoms use to make their shells and is a common constituent in marine mud. The sediment cores provide a record of thousands of years, so if the Amazon and this region of ocean was different long ago, he would see a record of it!
This USC team is also looking at the amount of oxygen made in the sea and how much gets into the water from the atmosphere. Air from the atmosphere contains argon; oxygen produced by plants (phytoplankton) has no argon. In order to make these measurements, Will and his team must carefully collect samples and preserve them for analysis with colleagues back in LA (Ed Young, UCLA; Laurence Yueng, USC and Masha Prokopenko, USC).
Dr. Berelson’s team includes 2nd year Grad student Laurie Chong who is extracting and analyzing pore water; Research professional Nick Rollins who assembles the traps and helps with all aspects of the research, John Fleming (grad student, who will join the cruise midway), and WHOI Tech Ellen Roosen who helps with the mechanics of the sediment corer.
Enjoy photos of the sunset from last night as well as clouds- so many great sky photo ops!. I’m trying to post some of the videos I’ve taken but it has proved to be more challenging- stay tuned!
Question of the Day
- Do the bacteria in the water make us sick?
Only a few of them. Bacteria are in every habitat on Earth, growing in soil, hot springs, radioactive waste, water, as well as in organic matter and the live bodies of plants and animals. Bacteria recycle nutrients, with many steps in nutrient cycles depending on these organisms, such as nitrogen fixation.