However, the way and extent to which this increased production at the base of the food web propagates up to the higher trophic levels and charismatic megafauna such as whales, seals and polar bears, is extremely uncertain and hard to predict. Other features of the habitat than sea-ice such as currents and waves, seabed topography and sediments, and land-based freshwater and nutrient inputs, also dictate patterns of production and suitability for individual species. In this project we will employ mathematics and computer science to predict the likely flows of nutrient through the marine food web, from microbes to megafauna, as the physical environment in the Atlantic Arctic changes, as it is expected to do over the coming decades. The mathematics will be incorporated into computer models which describe the complex network of interactions between living components of the food web and the dissolved and particulate, inorganic and organic nutrients. This whole complex web is driven by the seasonal fluctuations in sunlight arriving at the sea surface, and coupled to the physical circulation and three-dimensional mixing of the marine environment by winds, tides and freshwater-driven currents, which transport all the components of the food web around in space. To accomplish this we need to summarize scientific information from across the whole range biology, chemistry and physics and represent it in our models. We start the project with the legacy of two different working models of marine ecosystems developed for temperate shelf seas, which include most of the basic elements that we need to model the food webs in the Barents Sea, Fram Strait, and the wider Atlantic-Arctic in this project. We will be working with researchers in all of the already-funded Changing Arctic Ocean projects to develop the models, so as to best represent the special features that are needed to simulate high-latitude ecosystems, especially the role of sea-ice on the ecology. By the end of the project we will be able to quantify the extent to which climate change may affect the potential fishery yields of fish and invertebrates from the Atlantic Arctic, and also the trade-offs that exploiting these resources may entail with respect to the culturally important abundances of Arctic megafauna which rely on fish and invertebrates for their survival.