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Andrea Skloss's picture

What is that shinny object in the sky?

SunThe sun made a brief appearance today. What a wonderful time to be outside sampling

Lead-210

Dr. Lee Cooper team (University of Maryland) is calculating sedimentation rates in the Chukchi Sea. Sedimentation rates are the amounts of material that are deposited on the bottom of the ocean/sea in a year. They are measuring the amount of a naturally sediment occurring radioactive isotope Lead-210. Cooper's group also measures the amount of Cesium-137, which is a radioactive fallout product from nuclear bomb testing in the early 1960's (Deanna Wheeler in her August 23, 2012 PolarTREC journal has a detailed description of the chemistry of radiogenic isotopes.)

In pictures, I will describe the process of collecting and preparing the sample to be tested back in Maryland.

Gravity CoreThe gravity core is made of steel with a brass nose-piece

corer is lifted off the back deckThe corer is lifted off the back deck to be deployed into the sediments below.

Meter long sample The meter long sample is encased in a Plexiglas cylinder.

 2 cm slice sampleThe mud is pushed up the cylinder and 2 cm slice samples are placed in cans.

Can being sealedThe cans are sealed with a lid using the device in this picture.

Final product This is the final product...the sealed can.

Back in Maryland, a gamma spectrometer is used to measure the amount of Lead 210 and Cesium-137 in each sample. The cans are calibrated by counting known amounts of radioactive isotopes for that particular container size.

This investigation is particularly important to determine the rate as which a sediments are deposited. This information can be used to determine the fate of pollutants in the sediments, such as: how long it will remain in the ocean system, and how long before the contaminant is buried under new sediment.