Autumn phytoplankton blooms represent key periods of production in temperate and high-latitude seas. Biogenic silica (bSiO2) production, dissolution and standing stocks were determined in the Celtic Sea (United Kingdom) during November 2014. Dissolution rates were in excess of bSiO2 production, indicating a net loss of bSiO2. Estimated diatom bSiO2 contributed ≤10% to total bSiO2, with detrital bSiO2 supporting rapid Si-cycling. Based on the average biomass-specific dissolution rate (0.2 d-1), 3 weeks would be needed to dissolve 99% of the bSiO2 present. Negative net bSiO2 production was associated with low-light conditions (<4 E m-2 d-1). Our observations imply that dissolution dominates Si-cycling during autumn, with low-light conditions also likely to influence Si-cycling during winter and early spring.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)