Friday, July 17, 2015

Burkolator on the Brown: Our First OA Measurements

The first OA measurements we made once in U.S. waters (sadly there was no sampling in Canadian waters on the transit up to Alaska from Seattle due to a lack of clearance) are from a CO2 system known as a “Burkolator” (after designer Dr. Burke Hales, Oregon State University; Photo 1). This system will continuously sample surface seawater flowing through the ship during this cruise in the coastal Gulf of Alaska and the following cruise in the Bering Sea. The data from this system will provide a highly resolved snapshot of surface CO2 conditions along nearly half of the state of Alaska’s extensive coastline. We’re specifically interested in the saturation index of calcium carbonate; the mineral used by shelled marine organisms. The Burkolator is integrated with a series of ancillary sensors, such that the core CO2 system measurements we’re making are CO2 partial pressure (pCO2), total CO2 (TCO2), and pH (SeaFET). The system also tracks dissolved oxygen concentrations (SBE63), chlorophyll fluorescence (WETStar) and beam transmission related to the particle loads (C-Star). The combination of these measurements allows us to assess the physical and biological processes that shape the CO2 conditions in the surface water. An example of the data being collected and displayed in real-time is shown in Photo 2.

- Wiley Evans

Photo 1: The Burkolator installed on the NOAA Ship Ronald H. Brown. The various components are labeled and include: the control computer, electronics box, wet chemistry bench, liquid and gas standards, a bubble-typed equilibrator, SeaFET pH sensor, SBE63 dissolved oxygen sensor, C-Star beam transmissometer, and a WETStar chlorophyll fluorometer. Also shown is the Atlantic Oceanographic and Meteorological Laboratory (AOML) CO2 system that is permanently installed on the R. H. Brown and will provide a comparison dataset for the Burkolator. Photo taken by Wiley Evans

Photo 2: Example of the real-time data displayed by the Burkolator. This is a 4.5-hour window from July 17 showing pCO2 (white), saturation index for calcium carbonate (aragonite, blue), surface seawater temperature (red), salinity (green), and pH (purple). Photo taken by Wiley Evans

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