Antarctic Environment and Southern Ocean Process Study (AESOP)
The Antarctic Environment and Southern Ocean Process Study (AESOP), also known as the U.S. Southern Ocean Joint Global Ocean Flux Study (JGOFS), is an oceanic data collection endeavor aimed at quantifying ocean carbon fluxes.
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AESOP involved studies of two different and distinct regions. The first was the Antarctic Circumpolar Current (ACC) at 170 degrees W, where data were collected during five cruises (on the vessel R.V. Roger Revelle) from September 1996 through March 1998, as well as during selected transits between New Zealand and the Ross Sea. The objectives of the project were to:
- Better constrain the fluxes of carbon in the Southern Ocean,
- Identify the factorss and processes regulating the magnitude and variability of primary productivity, and
- Gain a sufficient understanding of the Southern Ocean to model past and present carbon fluxes with sufficient accuracy to predict its response to future global changes.
The chief findings of AESOP include:
- The Ross Sea continental shelf is among the most productive of all Antarctic systems, with a significant seasonal cycle;
- A seasonal bloom occurs in the region of the Polar Front;
- The annual production of the Ross Sea can be quantified by measuring deficits of nutrients and dissolved carbon dioxide;
- The phytoplankton blooms in the Ross Sea have essentially no losses due to microzooplankton herbivores;
- While iron did not stimulate phytoplankton growth in low silica waters north of the silica gradient, it substantially stimulated diatom growth in waters south of the gradient;
- The Polar Front region exhibits extreme mesoscale variability; and
- Dissolved organic carbon concentrations increase seasonally by less than a third as much as particulate organic carbon levels.