Sunday, August 12, 2012

Testing, testing...

Welcome aboard the main deck of the R/V New Horizon.  We’re underway on our five-day transit to our first station, and now that most of us are getting our sea legs, it’s time to make sure our equipment will be as ready as we are to get to work by conducting a test station.
Getting the MOCNESS ready

We started off with a test deployment of the Multiple Opening and Closing Nest and Environmental Sensing System (MOCNESS), a net system that allows us to open and close its nine nets in succession in order to sample separate layers in the water column.  Part of the goal of this test station is checking how well different instruments are calibrated so that when we arrive at the first real station, everything is ready to go.  In the case of the MOCNESS, that also includes the other instruments and tools attached to the frame, such as the flowmeter, which calculates how much water has passed through the nets based on the distance it travels.

Attaching the strobe lights to the frame of the MOCNESS when it is raised off of the deck.  The lights help limit avoidance so our samples more accurately represent the abundance of the animals.

Into the water it goes!

For some of the science party on this cruise, some equipment may be new or unfamiliar. John, one of the marine research technicians with us for the cruise, gave the group a tutorial on preparing the rosette system which has 25 bottles. The bottles have to be set up correctly so that they can be “fired” (closed) at specific depths to collect water samples. The whole apparatus also contains sensors for conductivity, temperature, and depth, also known as a CTD, which will measure the salinity and temperature of the water as the entire unit is lowered into the water column.

CTD tutorial

Aleck Wang, the lead scientist for the chemistry group, sets the final cable to hold open the cap of a bottle on the rosette

While the CTD is sent down to 500 meters below the surface, Katherine Hoering monitors its progress and the live temperature and salinity data being recorded by the computer.

We have various acoustic systems on board the ship, one of which is launched off the stern and can be sent down to various depths. This towed body, nicknamed the HammarHead, contains six transducers that can produce a broad range of sound (referred to as "broadband") to help us see what's below the surface.

The HammarHead towed body, named for its shape and its designer, WHOI engineer Terry Hammar

Once the sun goes down, the zooplankton come up.  Every day after sunset, the biology team will be launching a Reeve net that will go down as deep as 100 meters to sample the zooplankton that migrate upwards when it gets dark and the risk of predation lowers.

Amy Maas and Leo Blanco-Bercial drop the Reeve net over the side of the ship.
(Photo credits, R. Levine)

1 comment:

  1. There are many tests and some are more important and some are less. A general microbial test should be done annually as well as a test for nitrates.