Description: A decade of particle flux measurements providse the basis for a comparison of the eastem and westem provinces ofthe Nordic Seas. Ice-related physical and biological seasonality as well as pelagic settings jointly control fluxes in the westem Polar Province which receives southward flowing water of Polar origin. Sediment trap data from this realm highlight a predominantly physical flux control which leads to exports of siliceous particles within the biological marginal ice zone as a prominent contributor. In the northward flowing waters of the eastem Atlantic Province, feeding Strategie . life histories and the succession of dominant mesozooplankters (copepods and pteropods) are central in controlling fluxes. Furthermore, more calcareous matter is exported here with a shift in flux seasonality towards surnrner/autumn. Dominant pelagic processes modeled numerically as to their impact on annual organic carbon exports for both provinces confirrn that interannual flux variability is related to changes in the respective control mechanisms. Annual organic carbon exports are strikingly similar in the Polar and Atlantic Provinces (2.4 and 2.9 g m-2 y-1 at 500 m depth). despite major differences in flux control. The Polar and Atlantic Provinces. however, can be distinguished according to annual fluxes of opal ( l.4 and 0.6 g m-2 y-1) and carbonate (6.8 and 10.4 g m-2 y-1). lnterannual variability may blur this in single years. Thus. it is vital to use multi-annual data sets when including particle exports in general biogeochemical province descriptions. Vertical flux profiles (collections from 500 m, l000 min both provinces and 300-600 m above the seafloor deviate from the general vertical decline of fluxes due to particle degradation during sinking. At depths 〉 1000 m secondary fluxes (laterally advected/re uspended particles) are often juxtaposed to primary (pelagic) fluxes, a pattem which is most prominent in the Atlantic Province. Spatial variability within theAtlantic Province remains poorly understood. and the same holds true for interannual variability. No proxies are at hand for this province to quantitatively relate fluxes to physical or biological pelagic properties. For the easonally ice-covered Polar Province a robust relationship exists between particle export and ambient ice-regime (Ramseier et al. this volume; Ramseier et al. 1999). Spatial flux pattems may be differentiated and interannual variability can be analyzed in this manner to improve our ability to couple pelagic export pattems with benthic and geochemical sedimentary processes in seasonally ice-covered seas.

Description: Neritic ecosystems in the boreal zone generally maintain more plankton biomass over a longer period of the year than off-shore systems in the same latitude. Productivity is higher particularly during the summer stratification, between the spring and autumn phytoplankton blooms brought about by nutrients from sources other than pelagic remineralization. Plankton biomass levels maintained by recycling within a pelagic system tend to decrease with time if limiting nutrients bound in sedimenting particles are not replenished. In neritic environments, surface waters can receive nutrients from the land, but depending on water depth and local weather and geomorphology, replenishment can also come from nutrient-rich subthermocline water and sediments. In deeper bodies of water with a steep coastline, such as fjords, the sediment contribution will be less important (Takahashi et al. 1977) than in shallow water systems with more of their sediment surface within the euphotic zone (von Bodungen et al. 1975, Rowe et al. 1975).