Nutrient stress gradient in the bottom 5 cm of fast ice, McMurdo Sound, Antarctica

One-centimeter-scale vertical sampling of fast ice from McMurdo Sound, Anta rctica reveals evidence of progressive nutrient limitation with distance ab ove the ice/water interface. Over the bottom 6 cm photo-synthetically activ e radiation increases by between 1.8 and 3 times, C:N increases from 6.8 to 19.8 and delta(13)C increases from -18 to -12. Fatty acid composition also changes with a consistent decline in polyunsaturated fatty acids and a ris e in saturated fatty acids. These factors all suggest severe and progressiv e nutrient limitation with distance from the ice/water interface.