An objective of the Southern Ocean GLOBEC program is to understand physical and biological processes contributing to the overwintering success of larval krill (furcilia) along the Western Antarctic peninsula. On two cruises to the Western Antarctic peninsula, May-June (austral fall) and July-September (austral winter), the under ice distribution of furcilia and water column microplankton populations were assessed. In addition, on the winter cruise, feeding experiments were conducted to assess the potential utilization of microplankton as a food resource by furcilia. Under ice furcilia populations were quantified using stereo video cameras mounted on a Remotely Controlled Vehicle (ROV). Microplankton were enumerated microscopically after Lugols and DAPI staining, in addition to observing motion characteristics on live samples taken with Niskin bottles across a 200 nm square grid. Diver-collected furcilia were exposed to natural assemblages of microplankton collected from various depths in time-course particle depletion experiments. During the fall cruise, ice cover was sparse and furcilia were found in dense layers within the pycnocline. The ciliate Mesodinium sp. was a prominent member of the microplankton community in the surface mixed layer particularly where salinity was relatively low. Large centric diatoms, tintinnids and oligotrichous ciliates were abundant at the top of the pycnocline, while heterotrophic dinoflagellates dominated at depth. During the winter cruise, ice cover was heavy and reasonably continuous both in and off shore. Furcilia were found scattered throughout the grid in direct association with the under ice surface. Extremely dense patches were common where under ice surface roughness was great, but no inshore-offshore gradient or other spatial pattern was detected. Compared with the fall cruise, microplankton in the water column during the winter were sparse with greatest concentrations at both the ice/water interface and immediately above the pycnocline. Microplankton were also found in diver-collected under-ice material. Particle depletion feeding experiments showed furcilia were capable of clearing up to 98% of available particles between 50 and 150 um. Ingestion of microplankton by furcilia was confirmed by both DAPI and AO staining of gut contents and by conducting feeding experiments with fluorescently labeled prey. Together these results suggest furcilia spend the winter months associated with the under ice surface feeding on microplankton, a strategy which may play a major role in the overwintering of larval krill.