Wednesday, January 16, 2013

Antarctica Expedition: Studying the sea while at sea

Aquarium senior educator Jo Blasi is on expedition to Antarctica to help study the impact of climate change in these areas and changes in the marine ecosystem. She will be live blogging frequently about the expedition, research technologies and marine life encountered during the trip.

The Palmer LTER has very specific areas that they study. This is to make sure that the data that is collected aligns with a grid system year after year. This helps making the data analysis more consistent and meaningful over time. This grid system starts at Palmer Station and works south along the Western Antarctic Peninsula (WAP). Palmer LTER scientists take all kinds of samples along a predetermined set of the yellow stations as shown in the grid. We started at Palmer (green dot at the top of the grid), but we have since traveled to about the 200 line which is about half way down near the second green dot.  Can you find it?

LTER Grid system. Palmer Station is close to the top, near the 600.040 green dot (Photo credit: Palmer LTER)

The LMG is outfitted with instruments that collect information on air and water temperatures, salinity, and depth while we sail. Those are combined with the latitude and longitude of the ship. Together those generate a profile or picture of the water that we are traveling over at that particular time.

The XBT probe inside its protective covering. (Photo credit: Jo Blasi/Palmer LTER)

We have also been deploying XBT (eXpendable BathyThermograph) probes as seen in the photograph above. These instruments are released overboard and measure the ocean temperature as a probe drifts through the water. They consist of a dispensable probe, a data processing/recording system and a launcher. It's really cool looking

Copper wire used to transmit data back to the ship. (Photo credit Jo Blasi/Palmer LTER)

A thin copper wire connects the probe to a recording system that transmits the data in real time back to the ship the moment the probe hits the water. When the probe reaches its rated depth (which is a function of how fast the ship is traveling and the amount of wire contained within the spool) the profile is complete and the system is ready for another launch.

Launching these XBTs helps scientists generate better profiles of the ocean currents and how they combine over a particular area. They also track how temperatures change over parts of the ocean.  On this particular shift I was assigned to launch these while we were crossing the Drake.

Launching XBT probe overboard. (Photo credit Jo Blasi/Palmer LTER)

Over the course of crossing the Passage, we deployed 70 XBT probes around the clock for two days. Everyone on the ship took a shift. We worked in four-hour shifts to make sure the probes were dropped in the water every 30-35 minutes. That meant some people were up in the middle of the night! Luckily, my shift was from 8am to noon.  So, I got to sleep at a normal hour.  Thank goodness because we've put in some pretty crazy hours these last few days.

Still smiling! (Photo credit: Jo Blasi/Palmer LTER)

Data from the XBT. Temperature is on the x-axis and depth of water is on the y-axis.
 (Photo credit: Jo Blasi/Palmer LTER)

Here is a water profile on the computer screen on-board the ship after the XBT probe is finished with its descent.  Can you see what depth it stopped taking measurements?

All of Jo's entries are cross posted on the Palmer Long Term Ecological Research Station site here. Track her progress on the R/V Gould, and learn more about the Palmer Long Term Ecological Research Station.

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