Context-dependent consequences of Marenzelleria spp. (Spionidae:Polychaeta) invasion for nutrient cycling in the Northern Baltic Sea

Marenzelleria spp. are among the most successful non-native benthic species in the Baltic Sea. These burrowing polychaetes dig deeper than most native Baltic species, performing previously lacking ecosystem functions. We examine evidence from experiments, field sampling and modelling that the introduction of Marenzelleria spp. affects nutrient cycling and biogeochemical processes at the sediment water interface. Over longer time scales, bioirrigation by Marenzelleria spp. has the potential to increase phosphorus retention in bottom deposits because of deeper oxygen penetration into sediments and formation of a deeper oxidized layer. In contrast, nitrogen fluxes from the sediment increase. As a consequence of a decline of the phosphate concentration and/or rising nitrogen/phosphorus ratio, some Northern Baltic ecosystems may experience improvement of the environment because of mitigation of eutrophication and harmful cyanobacteria blooms. Although it is difficult to unambiguously estimate the ecosystem-level consequences of invasion, in many cases it could be considered as positive due to increased structural and functional diversity. The long-term interactions with the native fauna still remain unknown, however, and in this paper we highlight the major knowledge gaps. (C) 2015 Institute of Oceanology of the Polish Academy of Sciences., Production and hosting by Elsevier Sp. z o.o.Peer reviewe

Preparation, features, and efficiency of nanocomposite fertilisers based on glauconite and ammonium dihydrogen phosphate

This paper studies the chemical and mechanochemical preparation of glauconite with ammonium dihydrogen phosphate (ADP) nanocomposites with a ratio of 9:1 in the vol.% and wt.%, respectively. The methods include X-ray diffraction analysis, scanning electron microscope with energy-dispersive X-ray spectroscopy, transmission electron microscopy, infrared spectroscopy, and differential thermal analysis with a quadruple mass spectrometer. The manufactured nanocomposites keep the flaky glauconite structure. Some glauconite unit structures have been thickened due to minimal nitrogen (ammonium) intercalation into the interlayer space. The globular, granular, or pellet mineral particles of nanocomposites can be preserved via chemical techniques. Globular and micro-aggregate particles in nanocomposites comprise a thin film of adsorbed ADP. The two-step mechanochemical method makes it possible to slightly increase the proportion of adsorbed (up to 3.2%) and intercalated (up to 6.0%) nutrients versus chemical ways. Nanocomposites prepared via chemical methods consist of glauconite (90%), adsorbed (1.8–3.6%), and intercalated (3.0–3.7%) substances of ADP. Through the use of a potassium-containing clay mineral as an inhibitor, nitrogen, phosphorus, and potassium (NPK), nanocomposite fertilisers of controlled action were obtained. Targeted and controlled release of nutrients such as phosphate, ammonium, and potassium are expected due to various forms of nutrients on the surface, in the micropores, and in the interlayer space of glauconite. This is confirmed via the stepwise dynamics of the release of ammonium, nitrate, potassium, and phosphate from their created nanocomposites. These features of nanocomposites contribute to the stimulation of plant growth and development when fertilisers are applied to the soi

ROFI of the Elbe river during flood event, unstructured-mesh model study.

Regional models help to significantly improve our understanding of the global and regional cycles of, for example, carbon and nutrients. However, regional models often poorly resolve estuarine dynamics and are rather controlled by open boundary conditions. To investigate ecosystem processes in the south-eastern North Sea and Elbe estuary while avoiding the problems associated with nesting solutions we developed and applied an unstructured-mesh physical ocean model (FESOM-C). The FESOM-C model employs mixed unstructured-mesh methods and a finite - volume discretization. It is based on three-dimensional primitive equations for momentum, continuity, and density constituents. Vertically, the model uses a σ-coordinate system. The unstructured grid consists of quads and triangles zooming into the estuary, its vicinity and the coastline. Decrease in horizontal resolution provides a better numerical representation of coastal processes like asymmetries in tidal and residual flows, and periodic stratification. The lower resolution in the open sea allows conducting comparatively large regional studies. We developed a construction methodology for model setups in regions with complex coastal lines, including mixed mesh and bathymetry generation, open boundary and initial conditions and rivers distribution formation. The newly developed FESOM-C model could reproduce both barotropic and baroclinic dynamics of the coastal and estuary regions reasonably well. An Elbe summer flood event was well captured by the physical model. Investigation of flood event on ROFI of Elbe River were conducted with developed model by introduction of passive tracers in river outflow

Deep Insights into the Past: Terrestrial Permafrost Drilling Campaigns

Permafrost thaw is associated with impacts on climate, land surface and coastal and river bank structures. Thermokarst and thermoerosion, for example, are thaw processes that lead to ground subsidence. Two main factors of surface subsidence vulnerability are the sedimentological composition, including ground ice content, and the temperature state of permafrost. This surface destabilization is getting relevant because of a potential positive feedback of deep thaw to the global climate system through the release of greenhouse gases trapped beneath or in the permafrost, as well as through the release of so far freeze-locked old carbon by microbial decomposition. With these facts in mind the overarching aims of our drilling campaigns were to retrieve deep (> 50m) frozen and unfrozen sediment cores including sediments, ice, and organic components

Terrestrische Permafrost-Bohrkampagnen: Tiefe Einblicke in die Vergangenheit

Permafrosttauen hat Auswirkungen auf Klima, Landoberflächen, Küsten- und Flussuferstrukturen. Die eisreichen Permafrostböden im Lenadelta laufen Gefahr sich durch das Tauen abzusenken. Zwei Hauptfaktoren der möglichen Oberflächensenkung sind die sedimentologische Zusammensetzung einschließlich des Eisgehalts und der Temperaturzustand des Permafrosts. Diese Oberflächendestabilisierung wird klimarelevant, weil eine mögliche sich selbst verstärkende Rückkopplung durch tiefes Permafrost-Tauen möglich ist. Diese Rückkoppelung funktioniert über die Freisetzung von im Permafrost eingeschlossenen Treibhausgasen, sowie durch die Freisetzung von bisher eingefrorenem altem Kohlenstoff durch mikrobielle Zersetzung. Vor diesem Hintergrund waren die Ziele unserer Bohrkampagnen tiefe (>5m) gefrorene und ungefrorene Sedimentkerne einschließlich Sedimente, Eis und organische Bestandteile zu erbohren

Mixed-valence states formation in conformationally flexible metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin

Metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin have been prepared and characterized by UV-Vis, MCD, ^1H, ^(13)C, and variable-temperature NMR, APCI- and ESI-MS, and Mössbauer spectroscopy, while their redox properties were investigated using electrochemical (cyclic voltammetry and differential pulse voltammetry), spectroelectrochemical, and chemical oxidation approaches. The electronic structure calculations at Density Functional Theory level reveal that both compounds adopt saddle conformations and the HOMOs in both complexes are predominantly metal-centered, while the LUMOs predominantly consist of porphyrin π* orbitals. In spite of the rotational freedom of ferrocenyl substituents at room temperature, both metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin are able to form mixed-valence states upon the successive ferrocene-based two- and one-electron oxidations, respectively, as confirmed by UV-Vis, MCD, Mössbauer, electro-, and spectroelectrochemical methods, and thus, the earlier suggested (Boyd et al. Chem. Commun., 1999, 637) requirements for the formation of mixed-valence states in ferrocene-containing porphyrins should be revised

Mixed-valence states formation in conformationally flexible metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin

Metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin have been prepared and characterized by UV-Vis, MCD, ^1H, ^(13)C, and variable-temperature NMR, APCI- and ESI-MS, and Mössbauer spectroscopy, while their redox properties were investigated using electrochemical (cyclic voltammetry and differential pulse voltammetry), spectroelectrochemical, and chemical oxidation approaches. The electronic structure calculations at Density Functional Theory level reveal that both compounds adopt saddle conformations and the HOMOs in both complexes are predominantly metal-centered, while the LUMOs predominantly consist of porphyrin π* orbitals. In spite of the rotational freedom of ferrocenyl substituents at room temperature, both metal-free 5,10,15,20-tetraferrocenylporphyrin and 5,10-bisferrocenyl-15,20-bisphenylporphyrin are able to form mixed-valence states upon the successive ferrocene-based two- and one-electron oxidations, respectively, as confirmed by UV-Vis, MCD, Mössbauer, electro-, and spectroelectrochemical methods, and thus, the earlier suggested (Boyd et al. Chem. Commun., 1999, 637) requirements for the formation of mixed-valence states in ferrocene-containing porphyrins should be revised

Hypoxia in the Baltic Sea: Biogeochemical cycles, benthic fauna, and management

Open Access-maksut maksettu/Tutkijan ilmoitusPeer reviewe