A new approach to model oxygen dependent benthic phosphate fluxes in the Baltic Sea

Highlights • A new description of sediment phosphorus dynamics was implemented in a 3D-model. • Oxygen consumption affects oxygen penetration in coastal sediments. • Low oxygen concentrations determine the oxygen penetration in deeper water sediments. • More than 80% of the phosphorus loads (1980–2008) are retained in the Baltic Sea. • Phosphorus is released from anoxic sediments and retained in oxic sediments. Abstract The new approach to model the oxygen dependent phosphate release by implementing formulations of the oxygen penetration depths (OPD) and mineral bound inorganic phosphorus pools to the Swedish Coastal and Ocean Biogeochemical model (SCOBI) is described. The phosphorus dynamics and the oxygen concentrations in the Baltic proper sediment are studied during the period 1980–2008 using SCOBI coupled to the 3D-Rossby Centre Ocean model. Model data are compared to observations from monitoring stations and experiments. The impact from oxygen consumption on the determination of the OPD is found to be largest in the coastal zones where also the largest OPD are found. In the deep water the low oxygen concentrations mainly determine the OPD. Highest modelled release rate of phosphate from the sediment is about 59 × 103 t P year− 1 and is found on anoxic sediment at depths between 60–150 m, corresponding to 17% of the Baltic proper total area. The deposition of organic and inorganic phosphorus on sediments with oxic bottom water is larger than the release of phosphorus, about 43 × 103 t P year− 1. For anoxic bottoms the release of total phosphorus during the investigated period is larger than the deposition, about 19 × 103 t P year− 1. In total the net Baltic proper sediment sink is about 23.7 × 103 t P year− 1. The estimated phosphorus sink efficiency of the entire Baltic Sea is on average about 83% during the period

Linking process rates with modelling data and ecosystem characteristics

This report is related to the BONUS project “Nutrient Cocktails in COAstal zones of the Baltic Sea” alias COCOA. The aim of BONUS COCOA is to investigate physical, biogeochemical and biological processes in a combined and coordinated fashion to improve the understanding of the interaction of these processes on the removal of nutrients along the land-sea interface. The report is especially related to BONUS COCOA WP 6 in which the main objective is extrapolation of results from the BONUS COCOA learning sites to coastal sites around the Baltic Sea in general. Specific objectives of this deliverable (D6.4) were to connect observed process rates with modelling data and ecosystem characteristics. In the report we made statistical analyses of observations from BONUS COCOA study sites together with results from the Swedish Coastal zone Model (SCM). Eight structural variables (water depth, temperature, salinity, bottom water concentrations of oxygen, ammonium, nitrate and phosphate, as well as nitrogen content in sediment) were found common to both the experimentally determined and the model data sets. The observed process rate evaluated in this report was denitrification. In addition regressions were tested between observed denitrification rates and several structural variables (latitude, longitude, depth, light, temperature, salinity, grain class, porosity, loss of ignition, sediment organic carbon, total nitrogen content in the sediment,  sediment carbon/nitrogen-ratio, sediment chlorphyll-a as well as bottom water concentrations of oxygen, ammonium, nitrate, and dissolved inorganic  phosphorus and silicate) for pooled data from all learning sites. The statistical results showed that experimentally determined multivariate data set from the shallow, illuminated stations was mainly found to be similar to the multivariate data set produced by the SCM model. Generally, no strong correlations of simple relations between observed denitrification and available structural variables were found for data collected from all the learning sites. We found some non-significant correlation between denitrification rates and bottom water dissolved inorganic phosphorous and dissolved silica but the reason behind the correlations is not clear. We also developed and evaluated a theory to relate process rates to monitoring data and nutrient retention. The theoretical analysis included nutrient retention due to denitrification as well as burial of phosphorus and nitrogen. The theory of nutrient retention showed good correlations with model results. It was found that area-specific nitrogen and phosphorus retention capacity in a sub-basin depend much on mean water depth, water residence time, basin area and the mean nutrient concentrations in the active sediment layer and in the water column

Factors regulating the coastal nutrient filter in the Baltic Sea

The coastal zone of the Baltic Sea is diverse with strong regional differences in the physico-chemical setting. This diversity is also reflected in the importance of different biogeochemical processes altering nutrient and organic matter fluxes on the passage from land to sea. This review investigates the most important processes for removal of nutrients and organic matter, and the factors that regulate the efficiency of the coastal filter. Nitrogen removal through denitrification is high in lagoons receiving large inputs of nitrate and organic matter. Phosphorus burial is high in archipelagos with substantial sedimentation, but the stability of different burial forms varies across the Baltic Sea. Organic matter processes are tightly linked to the nitrogen and phosphorus cycles. Moreover, these processes are strongly modulated depending on composition of vegetation and fauna. Managing coastal ecosystems to improve the effectiveness of the coastal filter can reduce eutrophication in the open Baltic Sea.peerReviewe

Report on the nature and types of driver interactions including their potential future

The Baltic Sea is a dynamic environment responding to various drivers operating at different temporal and spatial scales. In response to climate change, the Baltic Sea is warming and the frequency of extreme climatic events is increasing (Lima & Wethey 2012, BACC 2008, Poloczanska et al. 2007). Coastal development, human population growth and globalization intensify stressors associated with human activities, such as nutrient loading, fisheries and proliferation of invasive and bloom-forming species. Such abrupt changes have unforeseen consequences for the biodiversity and the function of food webs and may result in loss of ecological key species, alteration and fragmentation of habitats. To mitigate undesired effects on the Baltic ecosystem, an efficient marine management will depend on the understanding of historical and current drivers, i.e. physical and chemical environmental conditions and human activities that precipitate pressures on the natural environment. This task examined a set of key interactions of selected natural and anthropogenic drivers in space and time, identified in Task 3.1 as well as WP1 and WP2 (e.g. physico-chemical features vs climate forcing; eutrophication vs oxygen deficiency vs bio-invasions; fisheries vs climate change impacts) by using overlay-mapping and sensitivity analyses. The benthic ecosystem models developed under Task 2.1 were used to investigate interactions between sea temperature and eutrophication for various depth strata in coastal (P9) and offshore areas (P1) of the Baltic Sea. This also included investigation on how the frequency and magnitude of deep-water inflow events determines volume and variance of salinity and temperature under the halocline, deep-water oxygen levels and sediment fluxes of nutrients, using observations and model results from 1850 to present (P1, P2, P6, P9, P12). The resulting synthesis on the nature and magnitude of different driver interactions will feed into all other tasks of this WP3 and WP2/WP4. Moreover, the results presented in this report improve the process-based and mechanistic understanding of environmental change in the Baltic Sea ecosystem, thereby fostering the implementation of the Marine Strategy Framework Directive

Modelling marine sediment biogeochemistry: Current knowledge gaps, challenges, and some methodological advice for advancement

The benthic environment is a crucial component of marine systems in the provision of ecosystem services, sustaining biodiversity and in climate regulation, and therefore important to human society. With the contemporary increase in computational power, model resolution and technological improvements in quality and quantity of benthic data, it is necessary to ensure that benthic systems are appropriately represented in coupled benthic-pelagic biogeochemical and ecological modelling studies. In this paper we focus on five topical challenges related to various aspects of modelling benthic environments: organic matter reactivity, dynamics of benthic-pelagic boundary layer, microphytobenthos, biological transport and small-scale heterogeneity, and impacts of episodic events. We discuss current gaps in their understanding and indicate plausible ways ahead. Further, we propose a three-pronged approach for the advancement of benthic and benthic-pelagic modelling, essential for improved understanding, management and prediction of the marine environment. This includes: (A) development of a traceable and hierarchical framework for benthic-pelagic models, which will facilitate integration among models, reduce risk of bias, and clarify model limitations; (B) extended cross-disciplinary approach to promote effective collaboration between modelling and empirical scientists of various backgrounds and better involvement of stakeholders and end-users; (C) a common vocabulary for terminology used in benthic modelling, to promote model development and integration, and also to enhance mutual understanding

The Copernicus Marine Environment Monitoring Service Ocean State Report

The Copernicus Marine Environment Monitoring Service (CMEMS) Ocean State Report (OSR) provides an annual report of the state of the global ocean and European regional seas for policy and decision-makers with the additional aim of increasing general public awareness about the status of, and changes in, the marine environment. The CMEMS OSR draws on expert analysis and provides a 3-D view (through reanalysis systems), a view from above (through remote-sensing data) and a direct view of the interior (through in situ measurements) of the global ocean and the European regional seas. The report is based on the unique CMEMS monitoring capabilities of the blue (hydrography, currents), white (sea ice) and green (e.g. Chlorophyll) marine environment. This first issue of the CMEMS OSR provides guidance on Essential Variables, large-scale changes and specific events related to the physical ocean state over the period 1993–2015. Principal findings of this first CMEMS OSR show a significant increase in global and regional sea levels, thermosteric expansion, ocean heat content, sea surface temperature and Antarctic sea ice extent and conversely a decrease in Arctic sea ice extent during the 1993–2015 period. During the year 2015 exceptionally strong large-scale changes were monitored such as, for example, a strong El Niño Southern Oscillation, a high frequency of extreme storms and sea level events in specific regions in addition to areas of high sea level and harmful algae blooms. At the same time, some areas in the Arctic Ocean experienced exceptionally low sea ice extent and temperatures below average were observed in the North Atlantic Ocean

Influence of resuspension on sediment-water solute exchange and particle transport in marine environments

Marine sediments contain a large pool of nutrients, which if released would contribute to increased eutrophication, in spite of decreased nutrient loads from land and atmosphere. Resuspension is a process, which might influence the release of nutrients from the sediment to the overlying water. The influence of resuspension on benthic fluxes of oxygen, dissolved inorganic carbon (DIC), nutrients, dissolved iron (dFe) and dissolved manganese (dMn) was therefore investigated in three different marine environments. The measurements were performed using a benthic lander with the advantage of operating in situ. The method of measuring the effects of resuspension was developed in the archipelago of Gothenburg (Paper I). This method was then further improved and used during field studies in the Gulf of Finland (GoF; Paper II) and in a Scottish sea loch (Paper III). During the latter study also the effects of massive (simulating dredging or trawling) and repeated resuspension events on the benthic fluxes were studied. Natural resuspension significantly increased the oxygen consumption in the GoF and at a station with organic rich sediment in Scotland. There were no significant effects of natural resuspension on nutrient, DIC and dMn fluxes, but the fluxes and concentrations of dFe increased at stations with low bottom water oxygen concentrations (GoF). Massive resuspension increased the oxygen consumption enormously and instantly changed the bottom water concentrations of phosphate (which decreased), DIC, silicate and ammonium (which increased). Results confirmed that the general magnitude of phosphate fluxes was dependent on the oxygen regime (GoF; Paper IV). However, results also showed a strong correlation between phosphate and DIC fluxes during anoxic conditions implying that phosphate fluxes are controlled by input and degradation of organic matter under anoxia. The internal load was calculated to be about 66 000 ton P yr-1 in the GoF. If all oxic bottoms below 40 m would turn anoxic the internal load was computed to increase with about 35 000 ton P yr-1. Results from a fully coupled high-resolution biogeochemical-physical ocean model, including an empirical wave model, showed that a large fraction of the sedimentary organic carbon has at least once been resuspended, and the largest contribution of resuspended organic matter to the total transport of particulate organic matter occurred at shallow transport and erosion bottoms (long-term average, 1979-2007) in the Baltic Sea (Paper V). The fraction of resuspended organic matter in the deepest areas of the Baltic Sea was low (< 10%) even though there was a large horizontal transport of suspended organic matter and a high sedimentary content of it. A map of different bottom types, accumulation, transport and erosion bottoms, was also created

Evaluation of open sea boundary conditions for the coastal zone. A model study in the northern part of the Baltic Proper.

The environmental conditions in the coastal zone are strongly connected with the conditions in the open sea as the transports across the boundaries are extensive. Therefore, it is of critical importance that coastal zone models have lateral boundary forcing of high quality and required parameters with good coverage in space and time. The Swedish Coastal zone Model (SCM) is developed at SMHI to calculate water quality in the coastal zone. This model is currently forced by the outcome from a one-dimensional model, assimilated to observations along the coast. However, these observations are scarce both in space, time and do usually not include all required parameters. In addition, the variability closer to the coast may be underestimated by the open sea monitoring stations used for the data assimilation. These problems are partly overcome by utilize the one-dimensional model that resolves all the variables used in the SCM. However, the method is not applicable for examine either the past period or future scenario where the latter analyze how climate change might affect the coastal zone. In the present study, we therefore evaluate the possibility to use results from a three-dimensional coupled physical and biogeochemical model of the Baltic Sea as open sea boundary conditions for the coastal zone, primarily to investigate the two periods mentioned above. Seven sensitivity experiments have been carried out in a pilot area of the coastal zone, the northern part of the Baltic proper, including the Stockholm Archipelago. The sensitivity tests were performed in order to explore methods to extract the outcome from the three-dimensional model, RCO-SCOBI, and apply as lateral boundary forcing for the SCM. RCO-SCOBI is a model for the open Baltic Sea with high horizontal and vertical resolution of the required variables. The results from the different tests were examined and evaluated against observations in the coastal zone. This was executed for both the physical and the biogeochemical variables utilizing a statistical method. The results from this study concluded that the outcome from the RCO-SCOBI is applicable as forcing files for the SCM. The best results in the tests was obtained with a method extracting depth profiles for the required variables from the RCO-SCOBI at a position 10 nautical miles to the east and 10 nautical miles to the south in the Baltic proper or north in the Gulf of Bothnia outside each of the outer basins.Miljötillståndet i Sveriges kustvatten är starkt kopplat till tillståndet i det öppna havet på grund av det stora vattenutbytet mellan dessa. Det är därför viktigt att modeller utvecklade för kustzonens vatten har drivning från utsjön av god kvalitet med bra täckning i tid och rum samt med information om de variabler som krävs. För att beräkna vattenkvalitén i kustnära vatten har SMHI utvecklat en modell kallad kustzonsmodellen (SCM). Den drivs för närvarande från öppna havet av resultatfiler från en en-dimensionell modell som med hjälp av observationer har korrigerat och förbättrat modellresultaten. Tyvärr är dessa observationer undermåliga i tid och rum, och saknar nödvändiga variabler för att få bra drivning av SCM modellen. Dessa mätstationer ligger också längre ut i öppna havet och kan därför underskatta variabiliteten närmare kusten för de olika parametrarna. Dessa problem löses delvis med den en-dimensionella modellen som beräknar alla de variabler som är nödvändiga i SCM. Dock är dessa resultat inte användbara om man vill undersöka en historisk period eller framtida klimatförändringar i kustzonen. På grund av dessa tillkortakommanden undersöker vi i denna studie om det är möjligt att istället ersätta dagens drivning från öppna havet med resultat från en tre-dimensionell, kopplad fysisk och biogeokemisk modell för Östersjön som drivning för SCM, framförallt för att undersöka de två ovan nämnda perioder. I denna studie har sju känslighetsexperiment utförts i en pilotstudie för Norra Östersjön, inklusive Stockholms skärgård. De sju känslighetsexperimenten utfördes för att utvärdera olika metoder att extrahera resultat-filer från den tre-dimensionella modellen RCO-SCOBI med avsikt att användas som drivning för SCM. RCO-SCOBI är en modell för Östersjön med hög horisontell och vertikal upplösning av de variabler som krävs. Resultaten för både de fysiska och biogeokemiska processerna från de olika testen undersöktes och utvärderades mot observationer i kustzonen med hjälp av en statistisk metod. Slutsaten från dessa test är att resultatfiler från RCO-SCOBI är tillämpbara som utsjödrivning för SCM. Den bästa metoden är att extrahera en djupprofil per variabel för varje ytterbassäng i SCM i en punkt 10 nautiska mil österut och 10 nautiska mil söderut i egentliga Östersjön eller norrut i Bottenhavet för varje ytterbassäng i SCM

Von der Shop-Stewards-Bewegung zum National Minority Movement die britische Gewerkschaftsopposition zwischen Syndikalismus und Kommunismus 1919-1924

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