Wintertime organic carbon export provides a potential food source for zooplankton in the High Arctic

Abstract

Abstract Pulsed particulate organic carbon export plays a vital role in sustaining Arctic marine ecosystems and the biological pump. Wintertime particulate organic carbon export in ice-covered Arctic waters is generally considered negligible due to light-limited local primary production. However, using time-series sediment-trap samples, we observe a high wintertime particulate organic carbon flux lasting over three months at the ice-covered Northwind Abyssal Plain in the High Arctic. We examine its drivers and implications for zooplankton. Here, we show that elevated particulate organic carbon fluxes during winter coincide with increased fecal-pellet carbon and zooplankton swimmer fluxes. Fecal-pellet evidence and nitrogen isotope values indicate that the wintertime carbon export represents a potential food source for zooplankton during the dark season. This wintertime carbon flux is consistent with lateral input, plausibly sourced from shelf and slope regions. Our results demonstrate that such wintertime carbon export provides an important food source for overwintering zooplankton, highlighting its ecological role in ice-covered Arctic ecosystems.