Using biomass accumulation to estimate Antarctic sea-ice primary production

• Main Authors: Deman, Florian, Roukaerts, A., Vancoppenolle, M., Tison, J.-L., Delille, Bruno, Dehairs, F., Fripiat, François
• Other Authors: FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
• Format: Conference Object
• Language: English
• Published: 2019
• Subjects: Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Antarc*; Antarctic; Sea ice; Southern Ocean
• Online Access: https://orbi.uliege.be/handle/2268/244524

With an extent varying between a maximum of 19 × 106 km2 in late winter and a minimum of 3 × 106 km2 in late summer, Antarctic sea ice is one of the largest ecosystems on Earth, most of which consists of annual pack ice. Primary production in-situ measurements in Antarctic sea ice, using either oxygen-based or tracer incubation methods, are relatively tricky to achieve and remain scarce. Thus, to estimate large-scale Antarctic sea-ice primary productivity, two approaches have been used. First, the use of sea-ice biogeochemical models suggest that Antarctic pack ice contributes to a small but significant fraction (10–28%) of the primary production in the ice-covered area of the Southern Ocean. Second, accumulation of organic matter trapped within sea ice during the growth season is likely to be representative of the net community production. More than 20 years ago, Legendre et al. (1992) used the few available observations to infer Antarctic sea-ice primary productivity. We believe that it is time to revisit this estimation by accounting from a much larger compilation of data (historical to present). Here, we present the first results using an updated dataset of historical ice cores sampled between 1989 and 2017 (± 400 pack-ice cores). These allow us to provide an updated estimation of the sea-ice primary production based on in-situ data, and its contribution to the SIZ and Southern Ocean. A comparison between pack and fast ice (± 110 fast- ice cores) will be also briefly discussed.