Sue Oltman: Approaching Latitude Zero, June 1, 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: June 1, 2012

Weather Data from the Bridge:
Air temperature: 23.7. C / 74.6 F
Humidity: 73.1%
Precipitation: 0.3 mm
Barometric pressure: 1013.15 mB
Wind speed: 4.7 kt SE
Sea temperature: 24.77 C

We are almost at the equator!  The coordinates of the Galapagos Islands, where Puerto Ayora is, are 0, 90W.  The weather has been warm but a nice pleasant breeze is going all the time – the trade winds, a constant wind out of the southeast. It’s helpful as the ship is heading in the same direction as the wind!  When out on deck, it feels like perfect weather, it’s easy to forget how direct the sun is so close to the equator. Sunscreen is a necessity!  We are approaching the place where every day is an equinox.

It’s neat to think I will be staying at a hotel on the equator (equalizer of day and night.) Students, when I get to my hotel I will check and see whether water goes down the drain clockwise or counterclockwise, as we discussed in science class!

Most of the crew will take the ship to its home port in San Diego after dropping the science team off in the Galapagos. A new team of scientists will be waiting to board. The Stratus Team is crunching away at data gathering and wrapping up our reports.  Thoughts are starting to drift towards scenery of volcanic islands, beaches, giant tortoises and exotic birds which we look forward to seeing very soon!  So the science continues, no matter where you go…but we have a few more days left as sailors!

The crew tries to arrange some fun on occasional nights as we have to make our own entertainment…there is no TV and very limited internet (quite slow when it works!) and of course, no leisurely phone calls or text conversations from out here in the deep blue.  Sometimes it’s a movie – North by Northwest (a theme – our direction of travel), City of God, and a North Korean movie none of us had ever seen, as well as a poker game.  Most of us have books we are reading, but it was a big surprise that there is a fantastic library here! It has a few dozen shelves of books, mostly fiction, something for everyone’s taste. I’ve already read two books and have started a third.

Melville's library
There are about twice as many books than are shown in this picture! The library also has a TV and DVD player for watching a movie.

There are few books on the Galapagos Islands floating around and we have all been skimming them to decide how we will spend our time when we arrive in port. Many of us like to listen to our iPods and I have mentioned before, spend some time exercising.  Photography is a shared hobby, too, and now that our cruise is nearing an end, there is a lot of photo sharing going on. A few crew members find some spare time to fish from the side as we move forward. The ones that have been caught were shared at mealtimes. I especially enjoyed the yellowtail!

Being on a ship for a couple of weeks has also given me a look behind the scenes for every shipment of imports that comes across the seas to ports in theUnited States, such as Brunswick, Georgia. Each cargo ship has a crew of people bringing the goods over safely, loading and unloading, and doing it again. We have traversed over 2,000 miles and done it in excellent weather. The shipping industry and the goods my family and I use is something I had not given a second thought to before.  I have a new appreciation for the maritime industry.

Science and Technology Log

Since deploying the moored buoy, we have put quite a few drifters in the water including the one I personalized for our school!

Launching a drifter
Elsie and Jamie launch a drifter, one of many data gathering instruments that will drift with the current and report ocean temperature, and its location is tracked online.

Since we are getting closer to land, there is a higher likelihood of finding fishing gear in the water, so we have to be on alert for that at all times. We don’t want our instruments to get tangled up in the long lines fishermen leave in the water hoping for a catch to come along.  One day, the ship did run into some long lines and had to stop and make sure it wasn’t in the propellers. Another very cool instrument we’ve been deploying are ARGO drifter floats http://argo.whoi.edu/argo.whoi_about.html – Think of a scientific instrument that will measure temperature, conductivity (salinity)  and depth and that can be programmed to move around at different depths, GPS keeping track of its location for several months or even years.  They have computer processors in them and a little motor that “drives” it deeper or shallower as the need for data at certain coordinates dictates. Here is a diagram of the ARGO drifters we have been launching. http://argo.whoi.edu/argo.whoi_components.html

As the data from last year’s Stratus 11 deployment is analyzed, plus the hourly data from our UCTD profiles, several trends have become evident. I have also been able to get a look inside some of the instruments. Can you imagine sending a tablet computer hundreds of meters into the ocean? That is exactly what has been done. In the photo, you can see an example of an instrument that measured ocean currents for a year at great depth and pressure.

Gathering data from the mooring
Sean Whelan downloads the data from instruments and then prepares the instruments to be shipped back to Woods Hole.
Seaguard Current meter picture
Collecting data from a current meter using the touch screen and stylus, this instrument has withstood a year of underwater conditions on a card like you keep in a digital camera.

There is also redundancy of instruments (more than one) in case one fails or the battery dies, which sometimes does happen. Regarding the trends – the science team has anticipated this, having seen it similarly each year, these are their hypotheses as the Stratus experiment continues.  As we near the equator, the salinity is rising – there is more evaporation when the sun is more direct. As some of the ocean water becomes humidity in the atmosphere, the salt is left behind in the ocean, as salt does not change to a vapor in our atmosphere – it is left dissolved in the ocean and thus increases the ocean’s salinity. A “big” increase in salinity would be 1 part per thousand in a small area, for example, so we are tracking the trend of small changes. In the hourly UCDT deployments we have been conducting, we have measured between 34.08 and 37.7 parts per thousand.

Checking data in the main lab
Bob Weller and Sebastien Bigorre check the monitors for the status of the multi beam sonar display.

Oxygen content is important for all life as well as for many practical applications.  The absence of oxygen (or lower amounts) allows other chemical reactions to take place in the water.  The formation of certain acids becomes possible, which is deadly for some organisms, and favorable for others. An example we saw of this was a piece of hardware that was on the mooring cable had a very low oxygen levels, had sulfuric corrosion on it.

Another measure important to scientists is fluorescence which detects the amount of phytoplankton in the ocean – small organisms at the base of the ocean food web which use the CO2 to reproduce.

Society has great dependence on the ocean to absorb the right amount of carbon dioxide in the atmosphere, but at a certain point, the ocean chemistry will change and affect this balance of life. Climate prediction allows us to keep the pulse of the stability of this balance and all of this data we have gathered is part of the scientific puzzle of climate prediction.


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