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This is the membrane inlet mass spectrometer used for continuous at-sea measurements of Ar and O2.
(Rachel Stanley)
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Towards a Mechanistic Understanding of Carbon Cycling in the Equatorial Pacific
Collaborators:
Prof Michael Bender (Princeton University)
John Kirkpatrick (University of Washington)
Dr. Nicolas Cassar (Princeton University)
Bruce Barnett (Princeton University)
Prof Jim Murray (University of Washington)
The ocean plays a fundamental role in the natural cycle of
CO2. Changes in the amount of marine net community production (NCP)
influence atmospheric CO2 levels. Understanding the controls on NCP
may therefore help us identify possible causes and effects of past climate
variability and improve future climate projections. The equatorial Pacific, the
largest natural oceanic source of CO2 to the atmosphere, is an ideal
testing ground for theories of the controls of NCP in the ocean because many of
the factors that have been proposed to control biological production (i.e. Fe,
Si, major nutrients, physical instabilities) vary spatially and temporally
throughout the region, making it a natural laboratory. Additionally, the
equatorial Pacific is a high nutrient, low chlorophyll (HNLC) region, and
processes there are representative of other such regions, including the
Subarctic Pacific and the Southern Ocean. In the stratified mixed layer, the
geochemical tracer O2/Ar reflects the balance between new community production
(NCP) and gas exchange whereas the tracer D17O reflects the balance between
gross primary production and gas exchange. We are using continuous measurements of
O2/Ar from an underway membrane inlet mass spectrometer (MIMS), discrete
measurements of D17O, and estimates of gas exchange in order to constrain NCP
and gross production throughout a wide region in the Equatorial Pacific. The
biological production rates estimated in this study are considered in relation
to iron measurements and other factors that might be controlling biological
production in this climatically important region.
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