Sue Oltman: Salinity and Seamount Sleuths, May 24, 2012

NOAA Teacher at Sea
Sue Oltman
Aboard R/V Melville
May 22 – June 6, 2012

Mission: STRATUS Mooring Maintenance
Geographical Area: Southeastern Pacific Ocean, off the coast of Chile and Ecuador
Date: May 24, 2012

Weather Data from the Bridge:
Air temperature: 18.3 C / 64.9 F
Humidity: 70.3%
Precipitation: 0
Barometric pressure: 1011 mB
Wind speed: 2.3 NNW
Sea temperature: 19.16 C

Personal Log

The weather has been terrific – clear, in the 60’s with a little wind, nice sailing with the current helping us along. We are in the trade winds region. The view from the bridge (Captain’s pilot house) is excellent.  Everyone is terrific and very patient in showing us the ropes. There’s plenty of time to get to know people.  I’m getting to practice my Spanish a bit with our 2 students from the University of Concepcion (Chile) and two more Spanish speakers, from Chile and Ecuador. The two others on watch with me are Seb Bigorre (WHOI) and Ursula Cifuentes, a grad student from Chile, so we speak some Spanish during the watches. Life on a ship is different, but some of the comforts of home are here, too. Thank goodness there is a laundry, otherwise I would have had to bring 3 weeks worth of clothes! The food has really been fantastic!

Mark serving up some great food
Mark is one of our friendly cooks who keeps everyone on the ship happy!
Mess deck
The mess deck is where we eat our meals, grab a snack, or sit to read or chat at off times.

The dinner tonight is carne asada (fajitas) and you can smell it cooking. Bob and Mark, our cooks, have also served us white bean chili, salads, cheeseburger sliders, roasted chicken, fish, pork roast and vegetables, seasoned hash browns, bacon and eggs, all kinds of fresh fruit, not to mention the desserts like blueberry cobbler and cinnamon rolls. 

With all this great food, I was thankful to find that the crew makes places on the ship to work out! Some do “laps” by walking the ship a few dozen times around. There is an exercise room with weights and bikes and more equipment can be found in other places around the ship.

Science and Technology Log

The Woods Hole UOP (Upper Ocean Processes group) and rest of the team is now in a rhythm of deploying probes and gathering data. Like super sleuths, we are tracking a cold, relatively fresh water mass which originates inValparaiso and moves northwest. This water mass lies under the warm, salty surface layer.  At 50 meters depth, there is a clear distinction in the water masses since we began deploying the UCTDs. Just like a detective matches fingerprints, we have a “fingerprint” of the cold, fresh water.  A seasonal thermocline has been identified! Nan Galbraith, a programmer from WHOI, is processing all of the numerical data into useful images.  The surface water layer (graph) has a temperature about 20º C and salinity > 35 ppt (parts per thousand). At 50 meters depth, the temperature abruptly drops to 17º C and falls to 7.5º C at 400 m which is the bottom depth we are testing; similarly the salinity drops to 34.1 ppt. Although we are traveling through water about 4,000 m deep, we are interested in tracking this water mass. I’m still having trouble remembering approximate Celsius to Fahrenheit conversions: here’s a link to help.

http://www.wbuf.noaa.gov/tempfc.htm

However, another factor has come into play which we must consider. We are nearing a tectonically active area – the Nazca Ridge, a fracture zone. There are many seamounts, some of which have not been previously mapped. Whoever is on watch must look at the ever-changing multi-beam sonar display to look for seamounts – we don’t want the instrument to slam into an underwater volcanic mountain! The closer we get to the Nazca Ridge, the higher the likelihood of seamounts.

Seamounts
We constantly monitor the multi beam sonar display for bathymetry and sea floor features. The red or yellow circular areas are seamounts.

All in all, we will cover about 2,268 miles until we reach the Galapagos, so the multibeam sonar is a critical piece of navigation equipment.

On the watches, as we deploy the UCTD probe, which looks like a 2 foot long bullet, weighing about 10 lbs., and good teamwork is the hallmark of a successful launch and recovery. Sometimes we are working in the dark with only the ship’s lights and a flashlight. I have learned how to make a splice in the line – the cord is only about 1 mm in diameter! This line and any splice must be strong enough to hold onto a 10 pound instrument being dragged though 400 m of water at 12 knots. Picture 3 people at 4 a.m. on a moving ship, using tiny instruments to sew a splice in a 1mm line, all while the line is attached to the winch. Like a surgical team, we are all focused and know what tool the splicer needs next. Sometimes quick thinking and a problem solving mindset is needed. There was a foam “bumper” that we had been attaching to the line to cover the probe when it got close to the boat. The probe is expensive and this was protection from it slamming into the steel fantail. When it was lost in the water, the team on watch used a nearby mop to protect the probe while reeling it in. On the next watch, Seb figured out a different solution.

Why does it smell like diapers in here?

Back in the lab a different bit of problem solving with the scientific method is going on! Often when buoys are recovered, they are fouled — covered with barnacles and all kinds of organisms, fishing line, etc. that get caught in them. Jeff Lord – mechanical whiz – has hypothesized that applying a better “anti-fouling” substance can keep these from affixing themselves to the equipment. He has liberally applied Desitin, a zinc oxide ointment, to the instruments. This is the same treatment for diaper rash on babies’ bottoms!  So therefore, the odor in the lab reminds us of diapers. It will be a year before we know if Jeff’s hypothesis is correct, because after the STRATUS 12 buoy is moored, it will be a year before it is recovered.  What do you think will happen?

Some of the science party was given a tour of the ships technical equipment behind the scenes. Bud Hale explained not only all of the monitors and ship terminology, but took us down into the equipment rooms where we encountered a gravimeter (measures gravity variations), modern gyros with optics and GPS (measures pitch, roll and heave).

Bud Hale
Bud is an expert on all things technical on the ship. He is more than happy to tell you how any of it works!

Tomorrow, we hope to see the desalination plant on the ship which gives us our fresh drinking water.

UCTD files
After each deployment of a UCTD, data is uploaded into the computer. I’m starting to get the hang of it!

Sue Oltman: Getting My Sea Legs, May 22, 2012

NOAA Teacher at Sea
Sue Oltman
Aboard R/V Melville
May 22 – June 6, 2012

Mission: STRATUS Mooring Maintenance
Geographical Area: Southeastern Pacific Ocean, off the coast of Chile and Ecuador
Date: May 22, 2012

Science and Technology Log

It’s finally the day we will leave port!  I’m awakened by the feeling of my bed shaking and a crash of something falling, this could have been an earthquake.  The science party boards the boat after breakfast and spends a lot of time fastening all equipment down and securing it to shelving; even my laptop needs to be affixed to my desk with Velcro.

My stateroom is on the 02 deck, which is one floor below the main deck. I’m in 02-50-2 with a private “head.” Everything is made of steel (even the toilet and shower) and is bolted down, too.

Stateroom
Here’s where I will sleep for the next two weeks…and take naps so I can do my 4 a.m. watch shift.

As we move out towards open  ocean, the R/V Melville – all 278 feet of it –  is moving northwest at about 11-12 knots and all seasoned hands comment on how calm the seas are. However, there are factors such as pitch, roll and heave which I am not accustomed to!  Ocean conditions affect the ship with  roll of about 3° to 5°  – swaying back and forth to the left (port) and right (starboard.)  Pitch is the hull tilting forwards or backwards and is about 1 ° or less.  Heave is vertical displacement of the ship and is a meter or less. The roll starts getting to me after dinner, despite the sea-sick medicine! Fortunately, after lying down for a while, the sickness passes.

Next, I went up to the lab where all the monitors are to see what I can learn about our course. Watching the multi-beam sonar display (from the Bathymetry XTD) as the ocean floor drops out from below us is fascinating. An array of 191 SONAR beams maps it out. The colors appear like the depth color key on classroom maps we use of the ocean floor – dark blue where deepest and yellow or even red where it is shallower.

The monitors showed the ocean floor depth as it dropped from 2500 m to about 4700 m in an hour or so. The ship was beginning to sail over the trench!

This monitor shows the bathymetry or depth of the ocean in real time as we sail.

Two safety drills were conducted – a fire drill and an abandon ship drill. There was also training on the scientific equipment we will deploy, the UCTDs  (underway conductivity, temperature and depth probes), and ARGO drifter buoys. Sean Whelan led the class on UCTD training and Jeff Lord prepped us on the drifters. These smaller buoys will be released and will float freely, carried by the currents.

The UCTDs will be deployed hourly around the clock on the aft deck (back of the ship.) Salinity and density are derived from these values. The probe is dropped into the water, will sample for about 2 minutes to 400 m or so and then be retrieved. The casting line is then rewound onto the spool to be ready for the next deployment like a sewing machine bobbin being wound.  The data is transmitted to the computer via Bluetooth when a magnetic key is inserted to activate it.

UCTD
A UCTD is taken back to the surface after gathering data. Sean Whalen, an Engineering technician, taught the class on UCTDs.

Everyone was trained how to use the winch as they will need to use it on watch. Each watch has 3 people and is 4 hours long, and then you have 8 hours off. My assigned watches are 0400 – 0800 hours and 1600-2000 hours (4 to 8) so I will need to alter my sleeping schedule! Those on watch must stay in the downstairs lab and conduct UCTD releases during those hours. The instruments inside the UCTD are very sensitive and costly and must be handled very deliberately.

There is one more session. Keith – the ship’s “res tech” or resident technician – conducts a CTD handling class. The “rosette: is the circular frame in which water sampling devices called CTDs are placed to take water sampled in international waters. These are different from the UCTDs because deep zone water is sampled for salinity and temperature. This will be done about 7 times on this cruise. It is large and the instruments are housed in a sturdier casing so it is heavier and the winch operator must lower this into the ocean with a crane.

We are looking forward to be seeing some great sunrises and sunsets from our research vessel during watches!

Sunset
Enjoying the spectacular sunset with me are Elsie Denton, volunteer translator, and Jamie Shambaugh of NOAA.