Deep-Sea Research II 48 (2001) 4127–4153 Nitrogen uptake kinetics in the Ross Sea, Antarctica

• Main Authors: William P. Cochlana, Deborah A. Bronkb
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2001
• Subjects: Austral; Ross Sea; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.521.2304; http://online.sfsu.edu/cochlan/Publications_files/Cochlan %26 Bronk 2001 DSR.pdf

The first estimates of uptake kinetic parameters for NH4 NO3 , and urea in the Ross Sea, Antarctica were measured on three cruises during austral late winter–early spring 1996 (pre-bloom), late spring 1997 (bloom development), and summer 1997 (bloom decline). Nitrogen (N) uptake experiments were conducted with water collected at the 50 % light penetration depth using trace-metal clean protocols and 15N tracer techniques. At all sites, ambient NO3 concentrations ranged from 5.8 to 30.5 mg-at N l1 and silicic acid concentrations were greater than 62.0 mg-at Si l1. The following trends were observed. First, based on maximum uptake rates (Vmax), apparent N utilization followed the order NO3 >NH4 +>urea during the pre-bloom and bloom development cruises. During the summer cruise, as the bloom was declining, the apparent order of utilization was NH4