The life cycle of Stephos longipes - an example for cryopelagic coupling in the Weddell Sea (Antarctica)

Abstract

The calanoid copepod Stephos longipes was the predominant calanoid copepod at most stations throughout the continental shelf area within the upper 50m of the water column. Generally, abundances inside the pack ice floes exceeded those in the under-ice water layer (UIWL) by one to three orders and the water column below by three to five orders of magnitude respectively. The mean population stage was lowest inside the ice floes followed by the UIWL and the water column. Also, nauplii and young copepodite stages (CI and CII) often outnumbered all other metazoan groups within and beneath the ice. Highest densities of S. longipes (>90 000 m-3) were observed in ice floes and UIWL samples where platelet ice was particularly frequent, probably as a result of the extreme stickiness of S. longipes eggs and their attachment to floating ice crystals. Fecal pellets of S. longipes, collected in the UIWL, were in most cases filled with sea ice algae. The life cycle of S. longipes is closely associated with the sea ice, especially platelet ice layers, where a high algal standing crop can sustain a sufficiently high secondary production in an otherwise food limited habitat. -from Authors