Organic carbon export and burial in coastal upwelling regions is an important mechanism for oceanic uptake of atmospheric CO 2. In order to understand how these complex systems will respond to future climate forcing, further studies of nutrient input, biological production and export are needed. Using a 7 Be-based approach, we produced an 18-month record of upwelling velocity estimates at the San Pedro Ocean Time-series (SPOT), Southern California Bight. These upwelling rates and vertical nutrient distributions have been combined to make estimates of potential new production (PNP), which are compared to estimates of net community oxygen production (NOP) made using a one-dimensional, two-box non-steady state model of euphotic zone biological oxygen supersaturation. NOP agrees within uncertainty with PNP, suggesting that upwelling is the dominant mechanism for supplying the ecosystem with new nutrients in the spring season, but negligible in the fall and winter. Combining this data set with estimates of sinking particulate organic carbon (POC) flux from water column 234 Th: 238 U disequilibrium and sediment trap deployments, and an estimate of the ratio of dissolved organic carbon (DOC):POC consumption rates, we construct a simple box model of organic carbon in the upper 200m of our study site. This box model (with uncertainties of ± 50%) suggests that in spring, ~28% of net production leaves the euphotic zone as DOC, of this, ~12% as horizontal export and ~16% via downward mixing. The remaining ~72% of net organic carbon export exits as sinking POC, with only ~10% of euphotic zone export reaching 200m. We find the metabolic requirement for the local heterotrophic community below the euphotic zone, but above 200m, is ~105 ± 50 mmol C m-2 d-1 , or ~80% of net euphotic zone production in spring.

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In agriculture, a large variability of objects in a range of sizes and shapes is found, leading to problems in size grading. For example, for a low-cost product such as potatoes, the predominantly used mechanical size-determining systems have errors of up to 30% and can cause damage, but they are cheap and have a throughput up to 20 tonnes per hour. Alternatives which can guarantee an improvement in accuracy and a financial gain for the companies are required. In this paper methods for the determination of volume and axis measurements using a simple ring sensor system are described. A modified co-ordinate system and the segmentation of the area between the ring and the object are used. The volume determination is independent of the direction of presentation of the objects. For the determination of axes, the objects must be presented in the longitudinal direction to allow the use of simple 2D algorithms. The accuracy of the system depends both on the number of transmitters and receivers placed on the ring and on its diameter. A small ring sensor system was developed, which can scan 3D objects in real time (36 000 potatoes, 3.6 tonnes per hour) with an accuracy of better than 5% for a volume larger than 100 cm 3 .

The presence of gray layers, representing flood deposits, has previously been well documented in sediments obtained from Santa Barbara Basin, California. We studied geochemical aspects of these layers, in particular the carbon and sulfur contents and isotopic compositions, and found evidence of rapid pyrite formation. The data are consistent with complete (or nearly complete) sulfate consumption within the pore waters of a gray layer. This requires sulfate reduction rates (SRRs) that exceed the rate of resupply by diffusion, thus on the order of milimolar per day. The apparent rapidity of this diagenetic reaction is addressed. The net result is the precipitation of authigenic pyrite crystals enriched in 34S that become part of the sediment record. Thus, any interpretation of S isotope fluctuations in the marine sedimentary rock record obtained from pyrite must take into account the phenomena we describe and document here.

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