Month: September 2015

We’re approaching the final day of our trip. I’ve spent countless hours in the Main Lab proctoring communications with the Bridge and our Science team, logging events, and keeping our monitoring systems somewhat in check. We’ve deployed and recovered OBEM’s almost 25 times over the past two weeks, along with having taken our antenna’s in and out several times due to some hazardous water encounters. We actually lost all activity from our porpoise array on their final tow due to fishing gear and long lines in the water. 3 out of the 4 had their electrodes destroyed. You can see where each one was lost when you go back through their incomplete data sets.

Today specifically, we will haul in our remaining Scripps OBEM’s from south of Martha’s Vineyard. As each is brought aboard, it gets somewhat disassembled, removing electrodes and data loggers and then the data is collected from the compact flash cards that the data loggers recorded to. We have left 5 OBEM’s at the bottom of the ocean that will remain for the next year. They were created by WHOI, they sit off the edge of the continental slope in deep water. They will monitor electromagnetic activity they encounter for use upon their collection in the following year.

I’ve learned about launching XBT’s and how the WinMK21 software works. I have played with the different phases, gain, and shadow reduction to get accurate depths on the Knudsen 3.5 Hz Sub-bottom Profiler. I also got some time into the Spectra Robtrack Interface, getting time estimates and seeing our plotted course. Furthermore, I’ve met a great group of people who will continue to contribute knowledge and ability in the future of the marine science industry.

Tomorrow, we will wait for our Pilot boat to bring us to our dock in the morning, probably right before breakfast time. We will begin our demobilization of the ship, collecting our equipment and things all together, and transport them off boat via cranes. 

All I can say is.. what a great experience I’ve had the pleasure of partaking in. I can’t wait to pursue my future opportunities!

~Kate

This post is certainly later than intended, but we’ve been in open-ocean since Thursday morning. Our first two days on shore were spend drilling new holes in the mounting plates for our winch. We used two methods, one of which was a magnetic drill, the other was using a drill press. We were tossed around quite a bit Friday night due to an on shore storm sending some wind our way. At first you don’t think you’ll do so well with the waves and boat motion but your body adapts and you get there. 

The goal of our trip is to use electromagnetic waves to detect freshwater reserves that may be under the oceans crust. We will cover two main plots, one of which has been drilled and fresh water already found. The other is thought likely to have fresh water present. The main steps for detection are to launch Ocean Bottom ElectroMagnetometer (OBEM) stations that will receive data from a long and short towed antenna (called a source) rigged to the aft of the vessel. We will also tow an array of 4 receivers off the aft as well. This way we can identify the most efficient way to detect fresh water reserves under the ocean crust. We are currently off the coast of New Jersey where we have already deployed the OBEM’s and are towing antenna’s above them

The main steps: 

1.) Deploy OBEM’s

2.) Deploy towed array

3.)Deploy the long antenna

4.)Deploy the short antenna

5.)Drive back over the OBEM’s with the vessel at a slow rate to send out signals that can be captured by data loggers.

6.) Retract the antennas, and the array

7.) Retrieve the OBEM’s from the ocean bottom.

After all this is done, we will then travel back north to south of Martha’s Vineyard and repeat.

The crew (Science and Technical) works in rotating shifts, 12 hours each, to make sure data is being sent and any significant occurrences are logged in a daily agenda. They have been a pleasure and quite kind and certainly make such a new experience easier for a new comer such as myself. There’s certainly more to come, and pictures as well when we get closer to shore with a good data connection.

Signing out,

Kate

 It has been such an incredible opportunity to work with scientists from Woods Hole and Scripps Institute in sending down instruments which have never been used for our purpose in mapping freshwater deposits under the seafloor. Working in 12 hour shifts from midnight to noon I have helped to assemble the Ocean Bottom Electromagnetic instruments and outfit them with batteries, hydrophones, and fluxgate magnetometers along with other instruments that will be recording the changes in frequency of electromagnetic waves as they travel through the ocean floor. We deployed those at specific intervals on the ocean bottom off the coast of NJ and then towed a dipole behind the boat that sent current through the water and generated a complex wave form which was then recorded by the OBEMs and also recievers also towed behind the boat. I have also participated in logging every deployment and recovery including Latitude and Longitude, boat and wind speed, course, depth, and have taken readings from echosounders, GPS recievers, Direct Positioning systems, and other complex multibeam sonar. The geophysics is a little over my head, but I get mini lectures from the enthusiastic scientists on board while we sit and tow our array for days, monitoring all systems on computer screens. I’ve also had tours of the bridge and engine room by the excellent crew. I’m loving it so far. We have now picked up the OBEMs after towing for a few days and are now en route to the continental shelf below Martha’s Vineyard, where we will deploy another kind of Ocean Bottom System which will sit below for 8 weeks and again deploy the OBEMs and tow our array before picking them up and heading back to Woods Hole on the 14th.