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18 pages, 8 figures, 1 table, 1 appendix, database is available for download from PANGAEA at https://doi.org/10.1594/PANGAEA.888182, The biological production of calcium carbonate (CaCO3), a process termed calcification, is a key term in the marine carbon cycle. A major planktonic group responsible for such pelagic CaCO3 production (CP) is the coccolithophores, single-celled haptophytes that inhabit the euphotic zone of the ocean. Satellite-based estimates of areal CP are limited to surface waters and open-ocean areas, with current algorithms utilising the unique optical properties of the cosmopolitan bloom-forming species Emiliania huxleyi, whereas little understanding of deep-water ecology, optical properties or environmental responses by species other than E. huxleyi is currently available to parameterise algorithms or models. To aid future areal estimations and validate future modelling efforts we have constructed a database of 2765CP measurements, the majority of which were measured using 12 to 24h incorporation of radioactive carbon (14C) into acid-labile inorganic carbon (CaCO3). We present data collated from over 30 studies covering the period from 1991 to 2015, sampling the Atlantic, Pacific, Indian, Arctic and Southern oceans. Globally, CP in surface waters (, The authors also recognise funding from the UK Natural Environmental Research Council (NERC), the US National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the Spanish Ministry of Science and Innovation

Uptake of the ammonium analogue methylamine hydrochloride was used to examine the mechanism of ammonium transport in several species of marine phytoplankton (mainly Skeletonema costatum, but also Thalassiosira weissflogii, Emiliania huxleyi and Gonyaulax polyedra). Ambient pH had no effect on the retention of methylamine between pH 3.6 to 9.2 HgCl2 markedly inhibited methylamine transport. Transport was temperature-dependent and the Michaelis-Menten equation described methylamine transport as a function of concentration in experiments of less then 20 to 30 min duration. Pulse-chase experiments showed that only 5 to 15% of intracellular methylamine was readily exchanged with external methylamine or ammonium, and the remaining 85 to 95% exchanged more slowly. These results suggest that methylamine transport, hence ammonium uptake, probably was an active metabolic process as it occurred against typical values of algal electrochemical gradients. The “acid-trap” model of ammonium transport was not consistent with these data. A two-compartment model where ammonium is transported into the cytoplasm and vacuole is proposed.

Vertical mixing is generally considered to be one of the most influential factors affecting phytoplankton abundance in the ocean (Sverdrup, 1953; Gran and Braarud, 1935). Changes in both phytoplankton abundance and species composition are thought to occur as a function of turbulence (Margalef, 1978). Research has therefore been directed at the sources of water column turbulence in nature and how these sources affect phytoplankton community dynamics.