The IceShark , an effective method for sampling plankton under sea ice

Abstract Seasonal sea ice plays a crucial role in shaping coastal ecosystem dynamics throughout the circumpolar region. Of particular interest to oceanographers is the ice‐ocean interface which functions as a multidimensional habitat, supporting both sympagic algae and pelagic phytoplankton in the under‐ice surface waters. Varying both spatially and temporally, these primary producers support and sustain zooplankton populations, forming the foundation of the arctic and subarctic coastal food webs. Current climate‐driven shifts in sea ice extent, duration, and thickness along the coast of Nunatsiavut, the homelands of Labrador Inuit in eastern Arctic‐subarctic Canada, are expected to disrupt plankton communities, potentially triggering cascading effects across higher trophic levels. Despite these ramifications, research focusing on plankton dynamics at the ice‐ocean interface is limited, largely due to restrictions associated with access and isolation of under‐ice surface waters, as well as difficulties in undertaking work in subzero conditions. In an effort to address this gap, we introduce a new sampling methodology, using a recently designed apparatus, dubbed the IceShark. With a compact size and targeted design, the IceShark collects plankton directly below the ice, running at an average speed of 0.91 ± 0.15 m s −1 , filtering an average volume of 8.61m 3 (± 1.37) over 20‐min of operation (0.41 m 3 /min). Here we discuss the design and fabrication of the IceShark and evaluate its performance during pilot deployments along a fjord system in Nunatsiavut.