Testing Water Samples

Mark fills the eggs with water drained from the Niskin bottles

Climate Variability on the East Coast (CLiVEC) researchers aboard are also examining the relationship between oxygen and primary production.  Mark (University of Washington) measures oxygen in the ocean waters both onboard and back in the lab using water collected with a Rosette sampler.   He drains water from the Niskin bottles into fragile 500 cc glass containers nicknamed “eggs.”  To avoid contaminating the water samples with oxygen from the air, he purges the transfer tube with carbon dioxide gas.  The eggs filled with ocean water are stored in cases that will be shipped back to the lab.

Eggs filled with water samples to be shipped back to the lab for analysis.

These eggs will be analyzed for stable oxygen isotope ratio (17O/16O relative to air) to determine primary production.

Mark performes the Winkler Titration in the lab onboard the Delaware II.

On board Mark measures the amount of dissolved oxygen in the ocean water with a chemistry process called the Winkler Titration (see picture of Mark in titrating in the lab).  The values he determines using Winkler Titration can then be used to calibrate dissolved oxygen concentrations collected with the Conductivity, Temperature, and Depth (CTD), which can be used to collect data more quickly than by taking water samples alone.  In addition, Mark is also collecting water samples to determine the dissolved inorganic carbon concentration.

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