Istituto di Scienze Marine     
Cozzi S., Cantoni C. Stable isotope (δ13C and δ15N) composition of particulate organic matter, nutrients and dissolved organic matter during spring ice retreat at Terra Nova Bay. In: Antarctic Science, vol. 23 (1) pp. 43 - 56. Cambridge Journals, 2011.
Concentration and isotope composition of particulate organic matter were analysed in five coastal sites placed on the annual fast ice and in the underlying water column at Terra Nova Bay. The highest increases of POC (< 2767 M C) and PON (< 420 M N) were reached in bottom ice and unconsolidated platelet layer, in connection with a large accumulation of nutrients and dissolved organic matter. Isotope POM composition highly varied in ice habitats (δ13CPOC: -30.7 to -15.0, δ15NPON: 1.8 to 9.9). Constant negative δ13CPOC (down to -29.3) and positive δ15NPON (up to 9.4) values characterised the upper ice horizons, indicating the prevalence of aged detritus in these assemblages. By contrast, isotope composition (δ13CPOC: -15.0 to -29.7, δ15NPON: 1.8 to 9.6) and POC/PON ratios (6.2 to 12.6) markedly changed in bottom ice and interstitial water, even on short temporal scales, because of the combined effects of internal growth and mixing among freshly produced biomasses. Sea ice breakout caused a large settling of particulate in the water column. It changed δ13CPOC (-27.8 to -22.8) and δ15NPON (7.9 to 1.8) values in suspended particulate matter, indicating that inputs from fast ice strongly affect the isotopic signature of particulate in Antarctic coastal waters.
URL: http://journals.cambridge.org/action/displayJournal?jid=ANS
DOI: 10.1017/S0954102010000611
Subject Ross Sea
sea ice

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