High-resolution trends of nutrients, DOM and nitrogen uptake in the annual sea ice at Terra Nova Bay, Ross Sea

Stefano Cozzi
2008 Antarctic Science  
High-resolution trends of nutrients and DOM are analysed, with respect to nitrate and ammonium uptakes, in two coastal stations placed on the annual land-fast ice at Terra Nova Bay. The highest accumulations of dissolved inorganic nitrogen (87.2 lmol N dm -3 ), reactive phosphorus (14.1 lmol P dm -3 ) and reactive silicon (22.9 lmol Si dm -3 ) were observed in the bottom ice, although this process was preceded by a nutrient decrease in an interior sea ice layer. In the upper layer of sea ice,
more » ... M was rather constant in concentration and P-deficient (C:N:P ¼ 377:34:1 -579:53:1). In the bottom and platelet ice, the accumulation of DOM (1277 lmol C dm -3 ; 108.2 lmol N dm -3 ; 7.67 lmol P dm -3 ) occurred with lower C:N:P ratios (123:14:1 -59:7:1), because of a major contribution of fresher organic matter. Nitrate (, 7.33 lmol N dm -3 d -1 ) and ammonium (, 2.85 lmol N dm -3 d -1 ) uptakes in the bottom ice were higher than in the platelet ice. The comparison between the data of N-uptake and the concomitant release of total dissolved nitrogen in the bottom ice indicated that the microbial community may be subjected to low growths in situ and high releases of dissolved nitrogen, when it accumulates in this sea ice habitat.
doi:10.1017/s0954102008001247 fatcat:otrea3flibbsdnndcnipf3uud4