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Abstract: The Kattegat forms the outer part of the Baltic estuary. It is characterized by a stable two-layer stratification maintained by approximately equal supplies of low saline water from the Baltic and high saline oceanic water from the Skagerrak. The nutrient supply to these waters increased rapidly during the past decades and oxygen deficits have been reported from different parts of the estuary. In this paper, we have calculated trends in nutrient and oxygen concentrations within the surface and deep waters of the Kattegat and adjacent waters. This has been done with available data for the past decades, with reference to nutrient supply and phytoplankton production.Oxygen concentrations within the deep water decreased from 4·58 to 4·08 ml l−1 between 1971 and 1982, indicating a 50% increase in oxygen consumption. Concentrations of Tot-N, Tot-P and inorganic nitrogen increased simultaneously, both in the surface water during the winter and in the deep-water during the summer. Changes in Tot-N and Tot-P were dominated by the Baltic water, while local supply to the Kattegat dominated the changes in inorganic nitrogen. Increases in Tot-N and Tot-P suggest a successively increasing biomass. The importance of local nutrient supply to the Kattegat was studied by comparing expected nutrient concentrations within the surface water (due to exchange with adjacent waters) with actually observed concentrations. 12. Barmawidjaja, D. M., G. J. van der Zwaan, F. J. Jorissen and S. Puskaric. 1995. 150 years of eutrophication in the northern Adriatic Sea: evidence from a benthic foraminiferal record. Mar. Geol., 122, 367-384. Abstract: The vertical distribution of benthic foraminifera in a sediment core in front of the Po delta has been studied in detail. According to our age model, based on Pb-210 and Cs-137 analyses of another core from exactly the same locality, the studied core spans the past 160 years. The radio-isotope profiles further show that sediment mixing is largely restricted to the top centimeter, suggesting that the core should provide an extremely detailed record of the youngest history of the northern Adriatic Sea. Benthic foraminiferal patterns and grain-size analyses indicate a number of substantial changes in sedimentation rate and food/oxygen availability in the benthic ecosystem. Changes occurring at about 1840 and 1880 can be attributed to man-induced changes in the main outflow canals of the Po river. The first one led to an important reduction of the marine vegetation cover which probably was present up to that date. The second change resulted in the present-day situation in which the Po outflow is passing the studied core locality close by. The local benthic foraminiferal associations indicate a steadily increasing nutrient load from 1900 AD onwards. This trend is interpreted as the effect of anthropogenic eutrophication due to agriculture and waste water disposal, although the faunal record as discussed here only gives a limited impression of the basin-wide development. A marked faunal transition around 1930 indicates intensification of the eutrophication; around 1960 the first signs of an increasing importance of anoxic events can be recognized. The faunal changes in the last decade, which are ascribed to changes in preservation potential, indicate that more intense or more prolonged anoxia started about 10 years ago, and that the ecological health of this part of the northern Adriatic probably is still in decline. 19. Bianchi TS, Lambert CD, Santschi PH, Guo LD. 1997. Sources and transport of land-derived particulate and dissolved organic matter in the Gulf of Mexico (Texas shelf/slope): The use of lignin-phenols and loliolides as biomarkers. Organic Geochemistry 27 (1-2): 65-78. Abstract: The fate and transport of terrestrial organic matter across the continental margin in the Gulf of Mexico was studied in 1992 and 1993 using chemical biomarkers. Lignin-phenols were utilized as biomarkers for terrestrial inputs and indicated that much of the terrestrial organic matter inputs were deposited on the shelf/break and slope. The lignin-phenol concentrations (normalized to carbon) in POC, HMW DOC, and sediments in slope waters were considerably higher than at other open ocean sites studied previously. The dominant mechanism for transport of terrestrially-derived POC and HMW DOC across the shelf and slope was hypothesized to be advection of riverine and: estuarine discharges through benthic nepheloid layers. Based on loliolide concentrations in the water column, we believe that lateral transport of these materials at the shelf/break (through extensions of benthic nepheloid layers) may have been an important mechanism for the injection of terrestrially-derived organic matter into deep slope waters. 21. Bierman, VJ Jr, Hinz SC, Zhu D, Wiseman WJ Jr, Rabalais NN, Turner RE (1994) A preliminary mass balance model of primary productivity and dissolved oxygen in the Mississippi River plume/inner Gulf Shelf region. Estuaries 17:886-899 Abstract: A deterministic, mass balance model for phytoplankton, nutrients, and dissolved oxygen was applied to the Mississippi River Plume/Inner Gulf Shelf (MRP/IGS) region. The model was calibrated to a comprehensive set of field data collected during July 1990 at over 200 sampling stations in the northern Gulf of Mexico. The spatial domain of the model is represented by a three-dimensional, 21-segment water-column grid extending from the Mississippi River Delta west to the Louisiana-Texas border, and from the shoreline seaward to the 30-60 m bathymetric contours. Diagnostic analyses and numerical experiments were conducted with the calibrated model to better understand the environmental processes controlling primary productivity and dissolved oxygen dynamics in the MRP/IGS region. Under water light attenuation appears relatively more important than nutrient limitation in controlling rates of primary productivity. Chemical-biological processes appear relatively more important than advective-dispersive transport processes in controlling bottom-water dissolved oxygen dynamics. Oxidation of carbonaceous material in the water column, phytoplankton respiration, and sediment oxygen demand all appear to contribute significantly to total oxygen depletion rates in bottom waters. The estimated contribution of sediment oxygen demand to total oxygen-depletion rates in bottom waters ranges from 22% to 30%. Primary productivity appears to be an important source of dissolved oxygen to bottom waters in the region of the Atchafalaya River discharge and further west along the Louisiana inner Shelf. Dissolved oxygen concentrations appear very sensitive to changes in under water light attenuation due to strong coupling between dissolved oxygen and primary productivity in bottom waters. The Louisiana Inner Shelf in the area of the Atchafalaya River discharge and further west to the Texas border appears to be characterized by significantly different light attenuation-depth-primary productivity relationships than the area immediately west of the Mississippi Delta. Nutrient remineralization in the water column appears to contribute significantly to maintaining chlorophyll concentrations on the Louisiana Inner Shelf. 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