In Situ Oxygen Sensor Calibration

点击翻译按钮获取中文摘要

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."The cycles of organic carbon and oxygen are linked by the stoichiometry of photosynthesis and respiration, the mass balance of oxygen in the upper ocean is an important tracer for determining the marine ?biological carbon pump?. The utility of this method has been demonstrated repeatedly at ocean time-series sites by monthly shipboard measurements of oxygen and inert gases. Recently it has been shown that it is possible to determine the net biological oxygen production using in situ sensors that measure oxygen and total dissolved gas pressure remotely on moorings. This approach is very sensitive to accurate O2 measurements that are presently possible only if oxygen sensors can be calibrated several times during the year, because they drift after several months in the euphotic zone because of biofouling. The only thing preventing oceanographers from using present and future open-ocean surface moorings to derive a global coverage of the net annual biological oxygen production is the change in accuracy of oxygen sensors over time. The PI?s request funding to develop a method of calibrating oxygen sensors in situ by periodically exposing the oxygen sensor deployed at several meters depth in the ocean to the atmosphere. Temperature and atmospheric pressure will be measured along with the atmospheric pO2 during the calibrations.Broader ImpactsThis work will foster international cooperation with Aanderaa scientists, and likely spur improvements in data processing and calibration approaches for these sensors on many types of platforms. The value of mooring data sets will be increased, and understanding gained on the marine biological pump. A student will be trained by in an area of chemical oceanography that is certain to need future leaders. If successful, moorings can be outfitted with the design, allowing carbon export to be estimated in many parts of the ocean. Further, if the technology can be applied to drifters, the accuracy of O2 measurements can be greatly increased worldwide.