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This field study examines the differences in phyto- and zooplankton in different depths in the water body of the Gullmarfjord. The Fjord is located at the west coast of Sweden and is fed by the waters of the Skagerrak, the Kattegat and the Baltic Sea. These waters create three layers of defined and different salinity (Vergara- Soto et al., 2010). This work focuses on the different types of plankton in the neritic layer and the first layer beneath the discontinuity layer and endeavours to count the amount of species and individuals in a sample volume of 10 l each. Many different species could be found, identified and photographed. It emerged that the amount of plankton in the surface water was considerably higher than beneath the halocline, but not of huge difference concerning the species found. The only species that could be found exclusively in the deep layer were larvae of Terebratulina retusa. Due to the common plankton blooms in autumn it was neither surprising to find high amounts of phytoplankton, such as Asterionellopsis glacialis or Chaetocerus deci- piens and Coscinodiscus sp. nor to find accordingly high amounts of first consumers, such as copepods and other crustaceans. An unexpectedly high amount of plastic fibres was found in the deep layer, which was presumably led into the fjord from the Baltic Sea and could pose a threat to invertebrates. Diese Feldstudie untersucht die Unterschiede von Phyto- und Zooplankton in verschiedenen Tiefen im Wasserkörper des Gullmarfjords. Der Fjord liegt an der Westküste Schwedens und wird von den Gewässern des Skagerrak, des Kattegat und der Ostsee gespeist. Dieses Wasser erzeugt drei Schichten mit definiertem und unterschiedlichem Salzgehalt (Vergara-Soto et al., 2010). Diese Arbeit konzentriert sich auf die verschiedenen Planktonarten in der neritischen Schicht und der ersten Schicht unter der Diskontinuitätsschicht und versucht, die Anzahl der Arten und Individuen in einem Probenvolumen von jeweils 10 l zu zählen. Viele verschiedene Arten konnten gefunden, identifiziert und fotografiert werden. Es stellte sich heraus, dass die Planktonmenge im Oberflächenwasser deutlich höher war als unter der Halokline, aber hinsichtlich der gefundenen Arten nicht sehr unterschiedlich. Die einzigen Arten, die ausschließlich in der tiefen Schicht gefunden werden konnten, waren Larven von Terebratulina retusa. Aufgrund der häufigen Planktonblüte im Herbst war es auch nicht überraschend, hohe Mengen an Phytoplankton wie Asterionellopsis glacialis oder Chaetocerus decipiens und Coscinodiscus sp. noch entsprechend hohe Mengen an Erstkonsumenten wie Copepoden und anderen Krebstieren zu finden. In der Tiefenschicht wurden unerwartet viele Plastikfasern gefunden, die vermutlich von der Ostsee in den Fjord geleitet wurden und eine Gefahr für Wirbellose darstellen könnten.

Results from the Swedish national marine monitoring in the pelagic during 2016 are presented. The institutes who conduct the national monitoring are SMHI (Swedish meteorological and hydrological institute), SU (Stockholm University) and UMF (Umeå marine sciences centre). The presented parameters in this report are; salinity, temperature, oxygen, dissolved inorganic phosphorous, total phosphorous, dissolved inorganic nitrogen, total nitrogen, dissolved silica, chlorophyll and phytoplankton. Secchi depth, zooplankton, humus, primary production, pH and alkalinity are also measured but not presented. Seasonal plots for surface waters are presented in Appendix I. Time series for surface waters (0-10 m) and bottom waters are presented in Appendix II. The amount of nutrients in the sub-basins of the Baltic Sea is presented per season and year in Appendix III.Exceptional events 2016 A warm September due to several high pressure systems, with temperatures more than one standard deviation above mean in almost all stations from Skagerrak, Kattegat and the Baltic Proper. Low oxygen in Kattegat bottom water during autumn as can be seen in the seasonal plots for both Anholt E and Fladen. Improved oxygen condition in the East Gotland Basin, due to an increased frequency of deep water inflows in comparison to the period 1983 until the large inflow in December 2014. The inflow of 30 km3 in the beginning of the year could be tracked in the deep water in the Eastern Gotland Basin in June. Elevated levels of silicate have been observed in the Baltic Sea since 2014 and the silicate levels were also elevated this year but mainly in the central and the northern parts of the Baltic Proper. In July there were high cell numbers of the dinoflagellate Dinophysis acuminata, which caused high levels of toxins in blue mussels. During this period it was forbidden to harvest blue mussels along the Bohus coast. Unusual long period of cyanobacteria bloom in the Baltic Sea. Resultat från Sveriges nationella samlade nationella marina övervakning i den fria vattenmassan under året 2016 presenteras. De nationella utförarna är Sveriges metrorologiska och hydrologiska institut (SMHI), Stockholms Universitet (SU) och Umeå marina forskningscentrum (UMF). De parametrar som presenteras i rapporten är salthalt, temperatur, syre, löst oorganiskt fosfor, totalfosfor, löst oorganiskt kväve, totalkväve, löst kisel, klorofyll och växtplankton. Även siktdjup, djurplankton, humus, primär produktion, pH och alkalinitet provtas men de presenteras inte. Säsongsfigurer tillsammans med statistik presenteras för ytvatten i Bilaga I. Tidsserier för ytvatten (0-10 m) och bottenvatten presenteras i Bilaga II. Mängden närsalter i Östersjöns delbassänger under vintern presenteras i bilaga III.Speciella händelser 2016 Flertalet högtryckspassager orsakade en ovanligt varm septembermånad, vilket gav yttemperaturer mer än en standard avvikelse över det normala vid nästa alla stationer i Skagerrak, Kattegatt och Östersjön. I Kattegatts bottenvatten var det mycket låga syrgashalter under hösten men förhållandena återgick till det normala under vintern. Detta syns framförallt i säsongsfigurerna för Anholt E och Fladen. Syresituationen i Östra Gotlandsbassängen har förbättrats något och anledningen är att antalet inflöden har blivit fler sedan det senaste stora inflödet som skedde i december 2014. Inflödet på 30 km3 i början av året kunde senare under juni spåras i bottenvattnet i Östra Gotlandsbassängen. Nivåerna av kisel i Östersjön har under de senaste åren varit över det normala och så även detta år men främst i de centrala och norra delarna av Egentliga Östersjön. I juli noterades förhållandevis stora mängder av dinoflagellaten Dinophysis acuminata. Detta orsakade förhöjda halter av Dinophysis-toxiner i blåmusslor vilket i sin tur ledde till att Livsmedelsverket förbjöd musselskörd i vissa områden längs Bohuskusten. Ovanligt lång blomning av cyanobakterier i Östersjön.

The relative importance of nutrient inputs from streams and the open sea for the water quality is a key issue for an effective management of eutrophication problems in estuaries. In order to resolve this question we have developed a coupled 3D hydrodynamic–ecological model with numerical nitrogen tracking for Horsens estuary, which is a typical Danish estuary that is shallow and well ventilated with water from the adjacent open sea. The nitrogen tracking technique revealed that nitrogen discharges from local streams accounted for the major part (40%–90%) of the nitrogen in NO3, NH4 and detritus whereas only 15% to 50% of the nitrogen in phytoplankton originated from streams. Effects of nitrogen loading reductions were most pronounced for nutrient concentrations and Chl a concentrations whereas the light condition was only slightly improved. The impact of stream nitrogen reductions on nitrate concentrations, Chl a concentrations and light attenuation was respectively 7, 2 and 3 times higher than the impact of open sea nitrogen reductions. Hence, even in estuaries that are well ventilated with water from the adjacent sea significant environmental improvements can be expected after reduction in local nutrient discharges.

A real meteorological situation characterized by strong spatial and temporal variability of the meteorological fields in a coastal region of eastern Denmark is examined in view of the transport of a passive tracer and dry deposition. Model simulations using a full mesoscale NWP model (COAMPS TM ) at different horizontal resolutions are per- formed. A realistic simulation showed that the differences in the amount of dry deposited matter can reach one order of magnitude and larger, during the period of one afternoon, depending on the model horizontal resolution. In addition, the results of an idealized experiment with straight coastline indicate that the horizontal model resolution alone is responsible for most of the differences. This study confirms the importance of high spatial and temporal resolution modelling for environmental applications. Repeating occurrences of harmful algae blooms and their economic consequences have recently received scientific interest in the area of the Kattegat strait (1), Figure 1. The project named MEAD (Marine Effects of Atmospheric Deposition; see (2)) was organized to concentrate on this particular issue. In summer time, when the riverine input of the nutri- ents is small, the atmospheric deposition is expected to play an impor- tant role in supplying the nutrients, needed for growth of phytoplankton and, in extreme events, its blooms. The abundant sources of ammonia at Jutland (northern Denmark) combined with prevailing western winds pres- ent favourable conditions for nutrification of the Kattegat. In order to study such a particular issue one should first recognize the general coastal problem, which is high spatial and temporal variability of the atmosphere. Due to relatively fast rates of deposition of ammonia, large gradients in the local dry deposition in the vicinity of sources are known to occur

Absorption spectra (250-800 nm) of yellow substance were measured in 1993 and 1994 along five onshore-offshore transects in the Southern Eight of the North Sea in different seasons. All spectra had a common shape, so the amount of yellow substance could be established using one reference wavelength as a proxy variable. The exponential slope parameter at 380 nm (S) of the absorption spectra ranged from -0.016 to -0.023 per nm when regression was based upon the 250-650 nm wavelength range; values were 25% lower when fitting was performed over the more restricted waveband 360-540 nm, partly due to a minor shoulder at 260-275 nm in all spectra. The concentration of yellow substance, expressed as the absorption coefficient at 380 nm (a(380); m(-1)), varied over an order of magnitude, from low values down to 0.17 m(-1) in the English Channel, up to 1.00-1.25 m(-1) near the Rhine and Scheldt outflow, to maxima of up to 1.75 m(-1) in the neritic-estuarine waters at the entrance to the shallow Wadden Sea. This regional distribution pattern was in agreement with the known water-mass circulation and with the location of sources of yellow substance: highest concentrations close to the shore under the influence of freshwater inflow, lower values with increasing distance from the coast, where Atlantic Ocean water is the major water-mass component. No significant seasonal variation in yellow-substance concentration was found anywhere when a correction was applied for salinity. Extrapolation to zero salinity yielded an absorption coefficient at 380 nm of 5.38 m(-1) for the freshwater input at both the Texel and Walcheren transects, but of 3.29 m(-1) at the Noordwijk transect, reflecting differences in yellow-substance concentration between the Rhine, the Meuse, and Lake IJssel, as previously noted in fluorescence measurements. Yellow-substance concentration was not only correlated with salinity but also, albeit much less, with chlorophyll concentrations; the contribution of phytoplankton to the yellow-substance pool was marginal but significant. A relation appeared to exist between yellow-substance absorbance at 380 nm and yellow-substance fluorescence intensity; fluorescence measurements in the southern North Sea can be translated to absorption (more appropriate for ocean colour detection by remote sensing) by equating I mFl unit to an absorption coefficient at 380 nm of 0.056 m(-1), and using the exponential relation a(ys)(lambda) = a(ys)(lambda(ref)) exp(-S(lambda - lambda(ref))) for extrapolation to UV-Vis spectral absorption. (C) 1999 Elsevier Science B.V. All rights reserved.

This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions. 2005 Elsevier Ltd. All rights reserved.

Spatial and temporal variations in pelagic carbon fluxes were examined by means of a large-scale and long-term monitoring data set from the Kattegat, a shallow marginal sea impacted by man-induced eutrophication. Flows of carbon, nitrogen and phosphorus in the upper mixed layer (0 to 10 m) were estimated from a simple descriptive model using measurements of primary production, temperature, and phytoplankton/zooplankton biomass as input variables. For all years combined, annual primary production at coastal stations (171 gC m -2 yr -1 ; 8 stations) was almost twice that at the deeper open-water stations (105 gC m -2 yr -1 ; 5 stations), which resulted in an annual primary production of 116 gC m -2 yr -1 for the region as a whole during the entire study period (1989 to 1997). Interannual variation in primary production was substantially smaller than the between-station variation. The phytoplankton spring bloom contributed substantially to annual production (10 to 20%), but the magnitude and timing were highly variable between years. Respiration accounted for on average 12% of the measured primary production. Annual sedimentation was estimated at 55 gC m -2 yr -1 , equivalent to 54% of net primary production. The estimated new production was significantly related to nitrogen loading from the land and atmosphere, and a regression analysis predicted declines of between 20 and 47 % in annual net primary production from a 50 % reduction in nitrogen loading. Carbon and nutrient fluxes are consistent with those of earlier studies from the Kattegat based on small-scale and short-term data sets. However, combining monitoring data with a budget model greatly improved data resolution in both time and space. Estimated C/N/P fluxes from the model can act as reliable indicators for assessing the state of eutrophication in the Kattegat and other inland seas impacted by man-induced nutrient loading.