Collective sinking promotes selective cell pairing in planktonic pennate diatoms

• DOI: 10.1073/pnas.1904837116
• Publication Date: 2019-07-25T23:49:13Z
• Authors: Joan S. Font-Muñoz; Raphaël Jeanneret; Jorge Arrieta; Sílvia Anglès; Antoni Jordi; Idan Tuval; Gotzon Basterretxea
• Keywords: Diatoms; 0303 health sciences; Life cycle; Movement; Microfluidics; Biological Sciences; Plankton; diatoms; 03 medical and health sciences; life cycle; 14. Life underwater; Rheology; collective sinking

Significance Planktonic pennate diatoms are a ubiquitous group of microalgae playing a major role as primary producers in aquatic ecosystems. Some species are also known to produce domoic acid, a neurotoxin that causes shellfish poisoning. Their reproduction is mostly accomplished through rapid clonal cell division, but eventual sexual exchange is required for population survival. How do nonswimming organisms find their partners in the water column? We demonstrate that planktonic pennate cells need to sink from surface turbulent waters to more stable environments where encounter rates, and thus pairing for sexual reproduction, are facilitated by viscous torques and collective interactions. This mechanism is key in our understanding of pennate diatom population dynamics and could help to improve prediction of some toxicity episodes.