Arctic PRoductivity in the seasonal Ice ZonE (Arctic PrIZE)

Arctic PRIZE will address the core objective of the Changing Arctic Ocean Program by seeking to understand and predict how change in sea ice and ocean properties will affect the large-scale ecosystem structure of the Arctic Ocean. We will investigate the seasonally and spatially varying relationship between sea ice, water column structure, light, nutrients and productivity and the roles they play in structuring energy transfer to pelagic zooplankton and benthic megafauna. We focus on the seasonal ice zone (SIZ) of the Barents Sea - a highly productive region that is undergoing considerable change in its sea ice distribution - and target the critically important but under-sampled seasonal transition from winter into the post-bloom summer period. Of critical importance is the need to develop the predictive tools necessary to assess how the Arctic ecosystems will respond to a reducing sea ice cover. This will be achieved through a combined experimental/modelling programme. The project is embedded within international Arctic networks based in Norway and Canada and coordinated with ongoing US projects in the Pacific Arctic. Through these international research networks our proposal will have a legacy of cooperation far beyond the lifetime of the funding. The project comprises five integrated work packages. WP1 Physical Parameters: We will measure properties of the water column (temperature, salinity, turbulent fluxes, light, fluorometry) in both open water and under sea ice by deploying animal-borne tags on seals which preferentially inhabit the marginal ice zone (MIZ). We will use ocean gliders to patrol the water around the MIZ and track it as the ice retreats northwards in summer. Measurements of underwater light fields will support development of improved regional remote sensing algorithms to extend the spatial and temporal context of the proposal beyond the immediate deployment period. WP2 Nutrient Dynamics: We will undertake an extensive program of measuring inorganic and organic nutrients, their concentrations, isotopic signatures and vertical fluxes to understand the role of vertical mixing and advection (WP1) in regulating nutrient supply to PP in the surface ocean. WP3 Phytoplankton Production: We will investigate nutrient supply (WP2) and light availability (WP1) linked to sea ice affect the magnitude, timing, and composition of phytoplankton production, and the role of seasonal physiological plasticity. Through new numerical parameterisations - cross-tuned and validated using a rich array of observations - we will develop predictive skill related to biological production and its fate; resolve longstanding questions about the competing effects of increased light and wind mixing associated with sea ice loss; and therefore contribute to the international effort to project the functioning of Pan-Arctic ecosystems. WP4 Zooplankton: Zooplankton undergo vertical migrations to graze on PP at the surface. We will use acoustic instruments on moorings and AUVs, with nets and video profiles to measure the composition and behaviours of pelagic organisms in relation in light and mixing (WP1) and phytoplankton production (WP3) over the seasonal cycle of sea ice cover. The behaviours identified will be used to improve models that capture the life-history and behavioural traits of Arctic zooplankton. These models can then be used to investigate how feeding strategies of key Arctic zooplankton species may be modified during an era of reducing sea ice cover. WP5 Benthic Community: We will use an AUV equipped with camera system to acquire imagery of the large seabed-dwelling organisms to investigate how changes in sea ice duration (WP1), timing of PP (WP3) and bentho-pelagic coupling (WP4) can modify the spatial variation in benthic community composition. We will also conduct time series-studies in an Arctic fjord using a photolander system to record the seasonally varying community response to pulses of organic matter.