Nitrogen uptake rates in phytoplankton and ice algae in the Barents Sea

• Published in: Polar Research
• Main Authors: Kristiansen, Svein, Farbrot, Tove
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norwegian Polar Institute 1991
• Subjects: Barents Sea; ice algae; Polar Research
• Online Access: https://polarresearch.net/index.php/polar/article/view/2308; https://doi.org/10.3402/polar.v10i1.6737

Uptake rates of NH4+, NO3? and dissolved organic nitrogen (urea) were measured in phytoplankton and in ice algae in the Barents Sea using a 15N-technique. NO3? was the most important nitrogen source for the ice algae (f-ratio = 0.92). The in situ irradiances in the subsurface chlorophyll maximum and in the ice algal communities were low. The in situ NO3? uptake rate in the ice algal communities was light-limited The in situ NO3? and NH4? uptake rates in the subsurface chlorophyll maximum were at times light-limited. It is hypothesised that NH4+ may accumulate in low light in the bottom of the euphotic zone and inhibit the in situ NO3? uptake rate.