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Summary. The distribution of diatoms around the subAntarctic Prince Edward Island archipelago, as affected by the island mass effect is examined. Collections were made by continuous flow filtration of surface waters interrupted arbitrarily to give individual integrated samples. These were analyzed and the number of each species per cubic meter determined. Chlorophyll a was measured spectrophotometrically. Potential Primary Productivity was measured by the carbon-14 method. The major inorganic nutrients were analyzed by on-board use of an autoanalyzer. In May 1987 a massive bloom of Chaetoceros radicans was encountered in the island waters. The distribution was found to be closely correlated with high Chl a and potential primary productivity values. Of the major inorganic nutrients analyzed silicate was found to be inversely correlated with phytoplankton standing stock. Nitrate and phosphate showed a complex patchiness which was, however, obviously correlated directly with the phytoplankton bloom. The nitrate/phosphate ratio is shown to be variable with time and this may be attributed to the high phosphate content of the island leachate or differential phosphate depletion at time of bloom. A situation is described where, in 1983, the temperate diatom C. radicans and the Antarctic silicoflagellate Dictyocha speculum occurred in bloom stage in adjacent, separate communities. This suggests that separate watermasses of different origin were present at the time.

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The strong coupling constant, s , has been determined in hadronic decays of the Z 0 resonance, using measurements of seven observables relating to global event shapes, energy correlations and jet rates. The data have been compared with resummed QCD calculations, which are combined with the O(2 s) theory. The seven measurements agree to about 10%, and the nal result, based on a weighted average, is: s (M Z 0) = 0 : 120 0:006 ; where the error includes both experimental and theoretical uncertainties. This value corresponds to renormalization scale = M Z 0 and the error includes the uncertainty in this choice of scale. The present measurement complements previous determinations using the O(2 s) QCD matrix elements alone, and yields a compatible result, with comparable errors.

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