Light and dark uptake of nitrate and ammonium by large oceanic dinoflagellates: Pyrocystis noctiluca, Pyrocystis fusiformis, and Dissodinium lunula1
Abstract
In 4‑h experiments, N‑depleted cells of Pyrocystis and Dissodinium species took up NO3− and NH4+ at almost equal rates both day and night when preconditioned on 12 : 12 LD cycle at light intensities sufficient to saturate division (42–67 µEin m−2 s−1).Pyrocystis fusiformis but not Pyrocystis noctiluca took up NO3 at a high rate when grown at 3 µEin m−2 s−1. There was no increase in the concentration of NH4+ within the large vacuoles of Pyrocystis cells during uptake of NH4+, but both NO3 and NH4+ were accumulated in the vacuole when external NO3− was supplied. In contrast, inorganic N did not accumulate in Dissodinium lunula cells during either NO3− or NH4+ uptake. Nutrient‑replete cells of P. noctiluca, P. fusiformis, and D. lunula stored in their vacuoles as inorganic N ca. 30, 5, and 2% of their cellular‑N requirements.
- Publication:
-
Limnology and Oceanography
- Pub Date:
- January 1977
- DOI:
- 10.4319/lo.1977.22.1.0073
- Bibcode:
- 1977LimOc..22...73B