Description: Author Posting. © Sears Foundation for Marine Research, 2007. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 65 (2007): 345–416, doi: 10.1357/002224007781567621

Description: This review provides an assessment of sediment trap accuracy issues by gathering data to address trap hydrodynamics, the problem of zooplankton "swimmers," and the solubilization of material after collection. For each topic, the problem is identified, its magnitude and causes reviewed using selected examples, and an update on methods to correct for the potential bias or minimize the problem using new technologies is presented. To minimize hydrodynamic biases due to flow over the trap mouth, the use of neutrally buoyant sediment traps is encouraged. The influence of swimmers is best minimized using traps that limit zooplankton access to the sample collection chamber. New data on the impact of different swimmer removal protocols at the US time-series sites HOT and BATS are compared and shown to be important. Recent data on solubilization are compiled and assessed suggesting selective losses from sinking particles to the trap supernatant after collection, which may alter both fluxes and ratios of elements in long term and typically deeper trap deployments. Different methods are needed to assess shallow and short- term trap solubilization effects, but thus far new incubation experiments suggest these impacts to be small for most elements. A discussion of trap calibration methods reviews independent assessments of flux, including elemental budgets, particle abundance and flux modeling, and emphasizes the utility of U-Th radionuclide calibration methods.

Description: WG meetings and production of this report was partially supported by the U.S. National Science Foundation via grants to the SCOR. Individuals and science efforts discussed herein were supported by many national science programs, including the U.S. National Science Foundation, Swedish Research Council, the International Atomic Energy Agency through its support of the Marine Environmental Laboratory that also receives support from the Government of the Principality of Monaco, and the Australian Antarctic Science Program. K.B. was supported in part by a WHOI Ocean Life Institute Fellowship.

Description: The brochure “Building Bridges in Marine Science Education” introduces the stunning spectrum of doctoral research in marine sciences in Kiel and highlights the outstanding features of the ISOS doctoral programme. A central element of the brochure are 10 doctoral candidate profiles that show the “face of the science” by giving doctoral researchers from a broad spectrum of disciplines the opportunity to introduce their work in their own words.

Description: Pelagic processes and their relation to vertical flux have been studied in the Norwegian and Greenland Seas since 1986. Results of long-term sediment trap deployments and adjoining process studies are presented, and the underlying methodological and conceptional background is discussed. Recent extension of these investigations at the Barents Sea continental slope are also presented. With similar conditions of input irradiation and nutrient conditions, the Norwegian and Greenland Seas exhibit comparable mean annual rates of new and total production. Major differences can be found between these regions, however, in the hydrographic conditions constraining primary production and in the composition and seasonal development of the plankton. This is reflected in differences in the temporal patterns of vertical particle flux in relation to new production in the euphotic zone, the composition of particles exported and in different processes leading to their modification in the mid-water layers. In the Norwegian Sea heavy grazing pressure during early spring retards the accumulation of phytoplankton stocks and thus a mass sedimentation of diatoms that is often associated with spring blooms. This, in conjunction with the further seasonal development of zooplankton populations, serves to delay the annual peak in sedimentation to summer or autumn. Carbonate sedimentation in the Norwegian Sea, however, is significantly higher than in the Greenland Sea, where physical factors exert a greater control on phytoplankton development and the sedimentation of opal is of greater importance. In addition to these comparative long-term studies a case study has been carried out at the continental slope of the Barents Sea, where an emphasis was laid on the influence of resuspension and across-slope lateral transport with an analysis of suspended and sedimented material.

Description: A decade of particle flux measurements providse the basis for a comparison of the eastern and western province s of the Nordic Seas. Ice-related physical and biological seasonality as well as pelagic settings jointly control fluxes in the western Polar Province which receive s southward flowing water of Polar origin. Sediment trap data from this realm highlight a predominantly physical flux control which leads to exports of siliceous particle s within the biological marginal ice zone as a prominent contributor. In the northward flowing waters of the eastern Atlanti c Province, feeding strategies, life histories and the succession ofdominant mesozooplankters (copepods and pteropods) are central in controlling fluxes. Furthermore, more calcareous matter is exported here with a shift in flux seasonality towards summer I autumn. Dominant pelagic processes modeled numerically as to their impact on annual organic carbon exports for both provinces confirm that interannual flux variability is related to changes in the respecti ve control mechanisms. Annual organic carbon export s are strikingly similar in the Polar and Atlantic Province s (2.4 and 2.9 g/m**2/y 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 (1.4 and 0.6 g/m**2/y) and carbonate (6.8 and 10.4 g/m**2/y). Interannual 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, 1000 m in 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 advectedlresuspended particles) are often juxtaposed to primary (pelagic) fluxes, a pattern which is most prominent in the Atlantic Province. Spatial variability within the Atlantic 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 seasonally 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 patterns may be differentiated and interannual variability can be analyzed in this manner to impro ve our ability to couple pelagic export patterns with benthic and geochemical sedimentary processes in seasonally ice-covered seas.