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A nested hydrodynamic model of the North Sea, using the COAWST framework, is described. A MatLab toolbox for computing and evaluating Lagrangian trajectories via data for surface currents, winds and waves is presented. Stokes Drift, wind drag, tidal currents and numerical handling of landpoints are found significantly impacting distribution and beaching of surface drifting objects in high resolution modeling. Theoretical wind drag estimates for GPS-drifters are compared to numerical estimates based on hydrodynamic, wind and wave data. Derived and theoretical drag parameters significantly differ and vary between three different drag models. Stokes Drift is found not satisfyingly representable by wind data in nearshore areas. Results recommend individual drag parameter estimations for different models, datasets and regions. Measured drifter paths and beaching locations in nearshore areas are qualitatively represented on short time scales but are lacking on longer time scales due to highly dynamical features.

Die Auswirkungen der zunehmenden Bodenversiegelung durch Schottergärten führt zu massiven Belastungen des Bodens. Um die Funktionen des Bodens zu erhalten, besteht Handlungsbedarf. Dabei ist die Verbreitung der bodenversiegelten Vorgärten ebenso zu beachten, wie die Beeinträchtigungen der Bodenfunktion und die daraus resultierenden Einflüsse für das Ökosystem. In diesem Zusammenhang werden in dieser Ausarbeitung die Bodenfunktion definiert, sowie diverse Einflussfaktoren dargelegt. Außerdem wird die Verbreitung von Schottergärten und anderen Gärten, die eine Bodenversiegelung darstellen, mit der Hilfe einer Geländekartierung untersucht. Schottergärten beeinflussen die Bodenfunktionen hinsichtlich des Lebensraumes für Flora und Fauna, des Wasserhaushalts, des Gasaustausches, der Bodenfruchtbarkeit und der Wiederherstellung der Ausgangszustandes. In den drei untersuchten Ortsteilen bestehen 10% der untersuchten Gärten aus Schotterflächen und 6,35% stellen eine Bodenversiegelung dar. Um die Bodenfunktion nachhaltig zu erhalten, muss die Verbreitung von bodenversiegelnden Gärten zukünftig gestoppt werden, da aktuell schon eine starke Verbreitung von Schottergärten vorliegt.

By now, microplastics are present in every environmental compartment of which sediments are considered one major sink. As a result, several approaches for their enrichment from sediments have been established in microplastic analysis. At the same time, the smaller microplastics gained increasing attention regarding their ecotoxicological relevance. A customized sediment separator was evaluated with trace amounts of small microplastic particles (150–300 mm) of the nine most common polymers. Separation was performed with sodium bromide (r ¼ 1.5 g cmE-3). The experimental recovery comprises pristine as well as incubated polymers to include early biofouling effects. Polymer quantification was achieved exclusively using pyrolysis-gas chromatography-mass spectrometry. The results reflected an overall mean recovery of 65%. Interestingly, the observed behaviour seems to be density related. While polymers of higher densities revealed higher average extraction efficiencies (74–97%), those of less dense polymers are reduced and span between 34 and 65%. These observations hypothesize possible polarity related surface interactions as a relevant factor for microplastic particle extraction. In contrast, the density of the separation fluid seemed to be of subordinate relevance, if small microplastic particles were extracted in trace amounts. Early biofouling enhanced recoveries of some polar polymers, whereas the effect on apolar polymers was even negative in some cases. In a comparative synopsis with other published density separation approaches, a limited number of comparable experimental setups concerning particle size, polymer density range and polymer concentration were revealed. Nonetheless, some related experiments point to similar density/polarity driven extraction behaviour. In conclusion, the presented study suggests a re-evaluation of current separation approaches for extraction of low number/mass concentrations of small microplastics from sediments to enable a more comp

The element silicon (Si) is required for the growth of silicified organisms in marine environments, such as di- atoms. These organisms consume vast amounts of Si to- gether with N, P, and C, connecting the biogeochemical cy- cles of these elements. Thus, understanding the Si cycle in the ocean is critical for understanding wider issues such as carbon sequestration by the ocean’s biological pump. In this review, we show that recent advances in process studies indicate that total Si inputs and outputs, to and from the world ocean, are 57% and 37% higher, respectively, than previ- ous estimates. We also update the total ocean silicic acid in- ventory value, which is about 24% higher than previously estimated. These changes are significant, modifying factors such as the geochemical residence time of Si, which is now about 8000 years, 2 times faster than previously assumed. In addition, we present an updated value of the global annual pelagic biogenic silica production (255 Tmol Siyr−1) based on new data from 49 field studies and 18 model outputs, and we provide a first estimate of the global an- nual benthic biogenic silica production due to sponges (6 Tmol Siyr−1). Given these important modifications, we hypothesize that the modern ocean Si cycle is at approxi- mately steady state with inputs = 14.8(±2.6) Tmol Siyr−1 and outputs = 15.6(±2.4) Tmol Siyr−1. Potential impacts of global change on the marine Si cycle are discussed.

The dynamics of the particulate organic carbon (POC) pool in the ocean are central to the marine carbon cycle. POC is the link between surface primary production, the deep ocean, and sediments. The rate at which POC is degraded in the dark ocean can impact atmospheric CO2 concentration. Therefore, a central focus of marine organic geochemistry studies is to improve our understanding of POC distribution, composition, and cycling. The last few decades have seen improvements in analytical techniques that have greatly expanded what we can measure, both in terms of organic compound structural diversity and isotopic composition, and complementary molecular omics studies. Here we provide a brief overview of the autochthonous, allochthonous, and anthropogenic components comprising POC in the ocean. In addition, we highlight key needs for future research that will enable us to more effectively connect diverse data sources and link the identity and structural diversity of POC to its sources and transformation processes.

Microplastics are of major concerns for society and is currently in the focus of legislators and administrations. A small number of measures to reduce or remove primary sources of microplastics to the environment are currently coming into effect. At the moment, they have not yet tackled important topics such as food safety. However, recent developments such as the 2018 bill in California are requesting the analysis of microplastics in drinking water by standardized operational protocols. Administrations and analytical labs are facing an emerging field of methods for sampling, extraction, and analysis of microplastics, which complicate the establishment of standardized operational protocols. In this review, the state of the currently applied identification and quantification tools for microplastics are evaluated providing a harmonized guideline for future standardized operational protocols to cover these types of bills. The main focus is on the naked eye detection, general optical microscopy, the application of dye staining, flow cytometry, Fourier transform infrared spectroscopy (FT-Ir) and microscopy, Raman spectroscopy and microscopy, thermal degradation by pyrolysis–gas chromatography–mass spectrometry (py-GC-MS) as well as thermo-extraction and desorption gas chromatography–mass spectrometry (TED-GCMS). Additional techniques are highlighted as well as the combined application of the analytical techniques suggested. An outlook is given on the emerging aspect of nanoplastic analysis. In all cases, the methods were screened for limitations, field work abilities and, if possible, estimated costs and summarized into a recommendation for a workflow covering the demands of society, legislation, and administration in cost efficient but still detailed manner.

Analysis of microplastics (MP) in environmental samples is an emerging field, which is performed with various methods and instruments based either on spectroscopy or thermoanalytical methods. In general, both approaches result in two different types of data sets that are either mass or particle number related. Depending on detection limits of the respective method and instrumentation the derived polymer composition trends may vary. In this study, we compare the results of hyperspectral Fourier-transform infrared (FTIR) imaging analysis and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) analysis performed on a set of environmental samples that differ in complexity and degree of microplastic contamination. The measurements were conducted consecutively, and on exactly the same sample. First, the samples were investigated with FTIR using aluminum oxide filters; subsequently, these were crushed, transferred to glass fiber filters, in pyrolysis cups, and measured via Py-GC/MS. After a general data harmonization step, the trends inMP contamination were thoroughly investigated with regard to the respective sample set and the derived polymer compositions.While the overall trends in MP contamination were very similar, differences were observed in the polymer compositions. Furthermore, polymer masses were empirically calculated from FTIR data and compared with the Py-GC/MS results. Here, a most plausible shape-related overestimation of the alculated polymer masses was observed in samples with larger particles and increased particle numbers. Taking into account the different measurement principles of both methods, all results were examined and discussed, and future needs for harmonization of intermethodological results were identified and highlighted.