Day 29 Tuesday October 25, 2011 10:56 GMT

Both scientists and crew are now getting excited about how close we are to Rio now.  There is a palpable change in the air, a mix of anxious, impatient excitement. 

Work is still going well and fast, in fact we have slowed down a little to give the samplers some time to process the water they have collected before running to take more and becoming backlogged. 

Yet more whales have been sighted and remains quite an amazing spectacle for those who can make it out of labs, or bed to see it.

Another group of scientists on board are our pH and Alkalinity team.

Way back when in our middle/high school/college chemistry classes we learned about the pH scale.  A scale ranging from 0-14 that designates the acidity (or lack thereof) level in a given substance, where 0 was extremely acidic, 14 was an extremely strong base and 7 was fairly neutral.

The pH is measured in the oceans to better study the Ocean Acidification (OA) mentioned in the previous post.  Measuring pH as well as Alkalinity gives two out of four parameters (the other two are DIC and partial CO2) and allows for the calculation of the missing parameters.  The samples collected are analyzed and a specific pH given to each one.  These sample values are then compared to ones taken on previous CLIVAR cruises along the A-10 transect line.  The differences in pH over the years of data gathered give an indication of the change in acidity of the ocean.

Alkalinity is used in much the same way, an indicator in ocean acidity, but is processed differently.  The water samples collected are transferred into closed processing system that prevents the intrusion of air or other particulates into the sample.  Hydrochloric acid is then slowly added until it reaches the same concentration as carbonic acid (Carbon derived acid responsible for ocean acidification and used in studying the carbon cycle).  The amount of acid that needs to be added to the seawater to get this concentration is an important measurement.  The less acid needed, the higher in acidity the sea water is to begin with.

Thanks for reading.
-Elizabeth

We are currently on track to Station 100.  Our position is:
30 0.001'S   and    39 53.74'W

Below are some photos of: a) The pH crew (Valentina and Tammy) -photo by Valentina, b) The Alkalinity crew (Carmen and Jen) -photo by Valentina, c) The view from the bridge