The Southern Ocean Iron RElease Experiment (SOIREE) - introduction and summary

This volume is dedicated to the Southern Ocean Iron RElease Experiment (SOI REE), the first in situ iron fertilisation experiment performed in the pola r waters of the Southern Ocean. SOIREE was an interdisciplinary study invol ving participants from six countries, and took place in February 1999 south of the Polar Front in the Australasian-Pacific sector of the Southern Ocea n. Approximately 3800 kg of acidified FeSO4. 7H(2)O and 165 g of the tracer sulphur hexafluoride (SF,) were added to a 65-m deep surface mixed layer o ver an area of similar to 50 km(2). Initially, mean dissolved iron concentr ations were similar to 2.7 nM, but decreased to ambient levels within days, requiring subsequent additions of 1550-1750 kg of acidified FeSO4. 7H(2)O on days 3, 5 and 7 of the experiment. During the 13-day site occupation the re were iron-mediated increases in phytoplankton growth rates, with marked increases in chlorophyll a (up to 2 mu gl(-1)) and production rates (up to 1.3 g Cm-2 d(-1)). These resulted in subsequent changes in the pelagic ecos ystem structure, and in the cycling of carbon, silica and sulphur, such as a 10% drawdown of surface CO2. The SOIREE bloom persisted for > 40 days fol lowing our departure from the site, as observed via SeaWiFS remotely sensed observations of Ocean Colour. Papers in this volume report in detail on as pects of this study, from the oceanographic setting of the experiment to a modelling simulation of the SOIREE bloom. A CD-ROM accompanies this volume and contains the main SOIREE datasets and ancillary information including t he pre-experiment 'desktop' database study for site-selection, and satellit e images of the SOIREE bloom. (C) 2001 Elsevier Science Ltd. All rights res erved.