Particulate protein-nitrogen in North Atlantic surface waters

• Published in: Marine Biology
• Main Authors: Packard, T. T., Dortch, Q.
• Other Authors: 7004249480, 6701785246
• Format: Article in Journal/Newspaper
• Language: English
• Published: 0025-3162 1975
• Subjects: 251001 Oceanografía biológica; North Atlantic
• Online Access: http://hdl.handle.net/10553/50901; https://doi.org/10.1007/BF00390573

Depth profiles of particulate protein-nitrogen at 4 oceanic and 2 upwelling stations in the North Atlantic Ocean were measured by a new fluorometric method. The protein-nitrogen in the upper 20 m ranged from 0.19 to 1.61 μg-at N/1 at the oceanic stations and from 0.43 to 3.54 μg-at/1 at the upwelling stations. The mean values in the euphotic zone were 0.54 μg-at N/1 for the oceanic stations and 1.70 μg-at N/1 for the upwelling stations. The ratio of protein-nitrogen to chlorophyll at the two sets of stations was 2.83 and 0.54 μg-at N/μg chlorophyll, respectively. Regression analysis of the pooled data yielded a detritus and zooplankton-free ratio of 0.38 μg-at N:μg chlorophyll. Calculations of the phytoplankton protein-nitrogen, based on this ratio, suggest that in the oceanic water only 20% of the sestonic protein-nitrogen is associated with the phytoplankton. In the upwelling waters, the phytoplankton may account for 65% of the sestonic proteinnitrogen.