Arctic Ice Algae Distribution as Function of Large Scale Sea Ice Variables

Giulia Castellani1, Hauke Flores2, Benjamin A Lange2, Carmen David2, Christian Katlein3, Ilka Peeken4, Marcel Nicolaus3, Martin J Losch3 and Jan A van Franeker5, (1)Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, (2)Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany, (3)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (4)Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Polar Biological Oceanography, Bremerhaven, Germany, (5)Wageningen-UR, IMARES, Den Burg, Netherlands
Abstract:

One of the most pronounced impacts of climate change is the declining sea ice cover in the Arctic Ocean, which has implications for sea-ice associated ecosystems that are strongly dependent on carbon produced by ice algae. In order to understand these ecosystems there is a need to understand the interaction between the physical and biological components of sea ice. Our current understanding of Arctic sea ice algae is based on observations with limited spatial coverage. Therefore, we aim to model the spatial distribution of ice-algae on a basin scale. Current sea-ice-ocean models do allow the representation of sea-ice variability on a scale of few km. Large scale characteristics of sea ice such as age, deformation, and snow cover, do affect the small scale ice properties, such as salinity, porosity, light transmission. The latter directly affect the sea ice algae content, but to what extent is not yet well understood. In this work we present a new parameterization for the sea-ice algae content developed with the aim to model the algae content and variability based on large scale sea-ice characteristics. This parameterization is tuned with data collected during a ship-based campaign to the Eastern Central Arctic in summer 2012. Sea-ice thickness and under-ice spectral surveys over different sea ice regimes were conducted with a Surface and Under Ice Trawl (SUIT) and a Remote Operated Vehicle (ROV). In addition, ice cores were extracted at several sites for chl a analysis. We use a coupled sea-ice-ocean model with a spatial scale of ~10 km and we show here the results for the temporal evolution of algae content in sea ice.