Recruitment patterns in Antarctic Peninsula shelf sediments : evidence of decoupling from seasonal phytodetritus pulses

Summer phytoplankton blooms on the West Antarctic Peninsula (WAP) shelf result in episodic deposition of labile food material for benthic detritivores. This summer deposition is thought to enhance benthic recruitment of macro- and megafauna. To explore seasonality in benthic recruitment, juvenile invertebrates (>100 μm) were collected in a seasonal time series at three stations on the WAP continental shelf. 4,098 juveniles were collected (average densities 2,000-7,000 m^sup -2^), with polychaetes dominant (2,581 individuals). The majority of polychaetes showed evidence of enhanced recruitment prior to the summer bloom, although patterns varied across stations. Additional taxa showed recruitment peaks in summer, but again, patterns varied among stations. Based on observed patterns, polychaete taxa are classified as "seasonal", "marginally seasonal", and "non-seasonal" recruiters, with the latter two patterns predominating. The year-round presence of small juveniles in most taxa suggests that recruitment occurs continuously, with periodic enhancement. Year-round recruitment is consistent with the presence of a persistent "food bank" of labile organic material in WAP shelf sediments, allowing recruitment to be largely decoupled from seasonal bloom dynamics.[PUBLICATION ABSTRACT]