Nutrient depletions in the Ross Sea and their relation with pigment stocks

The present article depicts a first attempt to relate the governing nutrient uptake regime and phytopigment signature of the Ross Sea. Based on nutrient and phytopigment data obtained during two cruises in the Ross Sea, two distinct groups were recognised. The first one was characterised by moderate nutrient (nitrate and silicic acid) depletions in combination with relatively high diatom and Phaeocystis abundance. The second group showed very low nutrient depletions and very poor diatom abundance. Average depth specific nitrate depletions were 8.1 and 1.1 ¼M and average silicic acid depletions were 21.5 and 1.3 ¼M, respectively. The nutrient consumption patterns did not match the conditions of silicic acid excess (SEA) or nitrate excess areas (NEA), a clear trend being probably obscured by very poor seasonal maturity of several sampling stations.