Global analysis of s easonality in the shell flux of extant

11 Shell fluxes of planktonic foraminifera species vary intra-annually in a pattern that appears to 12 follow the seasonal cycle. However, the variation in the timing and prominence of seasonal 13 flux maxima in space and among species remain poorly constrained. Thus, although 14 changing seasonality may result in a flux-weighted temperature offset of more than 5°C 15 within a species, this effect is often ignored in the interpretation of foraminifera-based 16 paleoceanographic records. Here we present an analysis of the intra-annual pattern of shell 17 flux variability in 37 globally distributed time series. The existence of a seasonal component 18 in flux variability was objectively characterised using periodic regression. This analysis 19 yielded estimates of the number, timing and prominence of seasonal flux maxima. Over 80% 20 of the flux series across all species showed a statistically significant periodic component, 21 indicating that a considerable part of the intra-annual flux variability is predictable. 22 Temperature appears to be a powerful predictor of flux seasonality, but its effect differs 23 among species. Three different modes of seasonality are distinguishable. Tropical and 24 subtropical species (G. ruber (white and pink varieties), N. dutertrei, G. sacculifer, O. 25 universa, G. siphonifera, P. obliquiloculata, G. menardii, G. rubescens, G. tenella and G. 26 conglobatus) appear to have a less predictable flux pattern with random peak timing in warm 27 waters. In colder waters, seasonality is more prevalent: peak fluxes occur shortly after 28 summer temperature maxima and peak prominence increases. This tendency is stronger in 29 species with a narrower temperature range, implying that warm-adapted species find it 30