Primary signal: Ecological and environmental factors - Report from WorkingGroup 2

Alkenone-based proxies are routinely used for paleoceanographic and climato logic reconstructions despite the fact that their calibration to environmen tal parameters is still a matter of debate. Significant differences are obs erved among culture calibration using different strains of alkenone produce rs, between regional field calibrations within the euphotic zone, and betwe en water column- and core top-base calibrations. The reasons for these disc repancies are not well understood and call for further evaluation. The poss ibility is raised that several aspects of genetics, physiology, and ecology of alkenone-producing haptophytes may be responsible, and suggestions of f uture research are proposed.