Micronutrient Distributions in the East Siberian and Laptev Seas during summer 1963

Abstract

Discusses phosphate, silicate, nitrate, temperature and salinity (T/S) data collected at 140 oceanographic stations occupied by the USCGC Northwind in these seas 7 Aug - 10 Sept 1963, cf No. 92559. These shallow seas deepen gradually toward the shelf edge, the East Siberian toward the E. Precipitation in the excess of evaporation should add ~50 km³/yr of fresh-water to the area; runoff from the seven rivers is ~250 km³/yr for the E Siberian and ~700 km³/yr for the Laptev Sea. Ice ~2 m thick forms in winter, summer melt is ~1 m, the difference compensated by net ice drift out of the area. Surface currents reduce the ice cover near shore in summer, but there is close-pack ice adjacent to Taymyr Peninsula. Annual and seasonal variations in air temperature, wind regime and river runoff obviate steady-state currents and T/S in the region. Silicate concentrations in the surface layer were almost always 5ug-at/liter, those of phosphate or nitrate or both were often so low as to suggest nutrient limitation of phytoplankton production. The nutrients in both seas are compared and discussed in relation to the intense stratification and turbidity of the waters, ice cover, and river discharge. The micronutrient distributions appear to be influenced mainly by summer phytoplankton bloom, respiratory processes, outflow of the Lena, and the different origins of the high-salinity waters found in the two seas.