Rotten ice layers are formed in the austral summer from the ice/snow interface down to 50cm (Thomas et al. 2008). Ice slush mixes with seawater, providing a high surface area and an abundance of nutrients from brine drainage of the surface layers (Ackley et al. 2008). This slowly releases algal cells over a long period of time into the water column and these species dominate the ice-edge blooms (Ligowski 1991). This is a strong feature in the Antarctic Ocean, with the community of algae species in the rotten ice being very similar to the communities within the ice pack (Papadimitriou et al. 2009). Rotten ice helps form the freeboard layers already discussed, when refreezing occurs (Ackley et al. 2008).