Vertical niche definition of test‐bearing protists (Rhizaria) into the twilight zone revealed by in situ imaging

摘要: Author(s): Biard, T; Ohman, MD | Abstract: © 2020 Association for the Sciences of Limnology and Oceanography The Rhizaria is a super-group amoeboid protists with ubiquitous distributions, from euphotic zone to twilight beyond. While rhizarians have been recently described as important contributors both biogenic silica carbon fluxes, we lack most basic information about their ecological habitats preferences. Here, using in situ imaging (Underwater Vision Profiler 5), characterize vertical niches different test-bearing pelagic rhizarian taxa southern California Current Ecosystem. We define three layers between 0 500 m occupied, respectively, by (1) surface dwelling mostly symbiont-bearing (Acantharia Collodaria), (2) flux-feeding phaeodarians lower epipelagic (100–200 m), (3) Foraminifera Phaeodaria populations adjacent oxygen minimum zone. then use Generalized Additive Models analyze response each category suite environmental variables. models explain 9% 93% total variance observed groups. temperature depth deep chlorophyll maximum appear main abiotic factors influencing upper 200 m, dissolved silicon concentration related abundance mesopelagic phaeodarians, though it explains only portion variance. importance biotic interactions (e.g., prey availability, predation, parasitism, symbiosis) still be considered, order fully incorporate dynamics biogeochemical models.