Alkenone and alkenoate distributions within the euphotic zone of the eastern North Atlantic: correlation with production temperature

This paper reports the concentrations and within-class distributions of long-chain alkenones and alkyl alkenoates in the surface waters (0–50 m) of the eastern North Atlantic, and correlates their abundance and distribution with those of source organisms and with water temperature and other environmental variables. We collected these samples of >0.8 μm particulate material from the euphotic zone along the JGOFS 20°W longitude transect, from 61°N to 24°N, during seven cruises of the UK-JGOFS Biogeochemical Ocean Flux Study (BOFS) in 1989–1991; the biogeographical range of our 53 samples extends from the cold (25°C) oligotrophic subtropical waters off Africa. Surface water concentrations of total alkenone and alkenoates ranged from 0.96) and had identical slopes (0.057) that were 50% higher than the slope (0.034) of the temperature calibration of U 37 k reported by Prahl and Wakeham ( Nature, 330, 367–369, 1987) over the same temperature range. These observations suggest either a physiological adjustment in biochemical response to growth temperature above a 16–17°C thresh