Pro-Oceanus Systems Incorporated (PSI) was founded in 1998 driven by the need to measure dissolved gases in situ with a high level of accuracy and reliability. Founders, Dr. Bruce D. Johnson and Dr. Craig L. McNeil, developed the technology for the first PSI GTD-Pro, at a time when measurements of dissolved gases in the ocean were made by collecting water samples for later analysis in the laboratory. Meanwhile, sampling methods in the oceanographic community had shifted to moorings, platforms, and submersibles that often involved deployments of six months to a year without the opportunity for calibrations. According to Dr. Johnson, who was then the Executive Director of the Canadian Joint Global Ocean Flux Study, "some of the most important measurements for determining carbon uptake by the oceans weren't being made because the technology just didn't exist".

With the challenge of meeting sampling needs, PSI has moved forward with the vision of providing highly stable and accurate dissolved gas sensors to the oceanographic and environmental monitoring communities. Our instruments are built to meet the complex needs of today's researchers and are currently being used at locations around the world.

Some Publications Related to PSI:

Anderson, M.L. and B.D. Johnson 1992, Gas Transfer: A gas tension method for studying equilibration across a gas-water interface. J. Geophys. Res., 97, 17899-17904

Farmer, D.M., C.L. McNeil and B.D. Johnson 1993. Enhanced air-sea gas flux due to bubbles. Nature, 361, 620-623.

McNeil, C.L., B.D. Johnson and D.M. Farmer 1995. In situ determination of nitrogen and oxygen concentrations in the ocean. Deep Sea Research, 42, 819-826.

McNeil, C., D. Farmer, M. Trevorrow and B. Johnson 1995. Development and testing of in-situ N2, O2 and gas tension sensors for oceanographic studies, in: Air-Water Gas Transfer - Selected Papers from the Third International Symposium on Air-Water Gas Transfer, Ed.'s B. Jahne and E.C. Monahan, AEON Verlag & Studio, 63454 Hanau, Germany, 891 pp. (1995)

Emerson, Steve, Charles Stump, Bruce Johnson and Dave Karl 2002. In situ determination of oxygen and nitrogen concentrations in the upper ocean. Deep Sea Research, 49, 941-952.

McNeil, C.L., D.R. Katz, R. Wanninkhof and B.D. Johnson 2006. Continuous shipboard sampling of dissolved N2, O2 and CO2, Deep-Sea Res. Let., LO1607.

McNeil, C.L., D.R. Katz, B. Ward, W.R. McGillis and B.D. Johnson, 2006. A method to estimate community metabolism from profiles of dissolved O2 and N2. Hydrobiologia, 571, 181-190.

McNeil, Craig, Eric D'Asaro, Bruce Johnson, Matthew Horn and Steve Emerson, A fast response gas tension device, In Press: Journal of Atmosphere and Ocean Technology; March 2006.