Estimating Biogenic Silica Production of Rhizaria in the Global Ocean

LLOPIS MONFERRER, NATALIA; BOLTOVSKOY, DEMETRIO; TREGUER, P.; MENDEZ SANDIN, M.; NOT, F.; LEYNAERT, A.

GLOBAL BIOGEOCHEMICAL CYCLES

AMER GEOPHYSICAL UNION

Año: 2020 vol. 34 p. 1 - 13

0886-6236

Siliceous polycystines and phaeodarians are open‐ocean planktonic protists found throughoutthe water column and characterized by complex siliceous skeletons that are formed, at least partly,through the uptake of silicic acid. These protists contribute to the marine organic carbon (C) and biogenicsilica (bSi) pools, but little is known about their contribution to the silica (Si) biogeochemical cycle. Herewe report the first measurements of the Si uptake rate of polycystine and phaeodarian cells from samplescollected in the Mediterranean Sea using the 32Si‐based method. The elementary composition (bSi,particulate organic carbon and nitrogen) of these organisms was also measured. Combining our results withpublished data on the distribution and abundance of Polycystina and Phaeodaria in the global ocean, weconclude that these organisms could contribute from 0.2 to 2.2 mmol Si m−2 of the marine standing stock ofbSi and from 2 to 58 Tmol Si yr−1 (1% to 19%) of the global oceanic biogenic silica production. Theimplications for the global marine Si cycle are discussed.