Bio-optical properties of the cyanobacterium <i>Nodularia spumigena</i>

In the last century, an increasing number of extreme weather events have been experienced across the globe. These events have also been linked to changes in water quality, especially due to heavy rains, flooding, or droughts. In terms of blue economic activities, harmful algal bloom events can pose a major threat, especially when they become widespread and last for several days. We present and discuss advanced measurements of a bloom dominated by the cyanobacterium Nodularia spumigena conducted by hyperspectral optical technologies via experiments of opportunity. Absorption coefficients, absorbance and fluorescence were measured in the laboratory, and these data are available at https://doi.org/10.4121/21610995.v1 (Wollschläger et al., 2022), https://doi.org/10.4121/21822051.v1 (Miranda et al., 2023) and https://doi.org/10.4121/21904632.v1 (Miranda and Garaba, 2023). Data used to derive the above-water reflectance are available from https://doi.org/10.4121/21814977.v1 (Garaba, 2023) and https://doi.org/10.4121/21814773.v1 (Garaba and Albinus, 2023). Additionally, hyperspectral fluorescence measurements of the dissolved compounds in the water were carried out. These hyperspectral measurements were conducted over a wide spectrum (200–2500 nm). Diagnostic optical features were determined using robust statistical techniques. Water clarity was inferred from Secchi disc measurements (https://doi.org/10.1594/PANGAEA.951239, Garaba and Albinus, 2022). Identification of the cyanobacterium was completed via visual analysis under a microscope. Full sequences of the 16S rRNA and rbcL genes were obtained, revealing a very strong match to N. spumigena; these data are available via GenBank: https://www.ncbi.nlm.nih.gov/nuccore/OP918142/ (Garaba and Bonthond, 2022b) and https://www.ncbi.nlm.nih.gov/nuccore/OP925098 (Garaba and Bonthond, 2022a). The chlorophyll-a and phycocyanin levels determined are available from https://doi.org/10.4121/21792665.v1 (Rohde et al., 2023). Our experiments of opportunity echo the importance of sustainable, simplified, coordinated and continuous water quality monitoring as a way to thrive with respect to the targets set in the United Nations Sustainable Development Goals (e.g. 6, 11, 12 and 14) or the European Union Framework Directives (e.g. the Water Framework Directive and Marine Strategy Framework Directive).</p

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this paper we describe nonlinear Galerkin methods for evolution problems with nonlinear strongly monotone Lipschitz continuous operators. It will be shown that the solution of the Cauchy problem for the original operator can be approximated this way, but, in general, we can not prove the strong convergence in L 2 ([0; T ]; V ) as it holds for the usual Galerkin approximations in this case. Concerning monotone operators we refer to [1], but the reader is briefly remembered to some definitions or facts on monotone operators. Let (V; k:k) be a real separable reflexive Banach space continuously embedded into a Hilbert space H such that V ae H is a dense set. The scalar product and the norm in H are denoted by (:; :) and j:j, respectively. The natural duality pairing o

Fluorescence measurements of dissolved matter during RV METEOR cruise M148/2 in the Benguela Upwelling System and Angola Gyre

Water samples were taken from surface, deep chlorophyll maximum (DCM), oxygen depleted zone underneath the DCM and at depth layers aboard the RV Meteor during the cruise M148-2 in July 2018. The cruise was conducted in the Atlantic Ocean covering the Angola Gyre as well as the Benguela Upwelling System off the coast of Namibia. Here we report the measurements of fluorescent dissolved organic matter (FDOM) and chlorophyll-a fluorescence properties that were completed immediately after sample collection from the CTD rosette on board RV Meteor. 250 ml of water sample was poured into Schott glasses covered in aluminum foil to create a dark container and was left to reach room temperature for about 30 to 60 minutes. Filtration for the FDOM samples was completed using a 25 mm Nuclepore with pore size of 0.2 µm filter syringe and the filtrate was poured directly into a 1 cm quartz cuvette that had been pre-rinsed with Milli-Q water. This cuvette was again pre-rinsed three times with the filtrate water before measurement as recommended (Garaba et al., 2014). For the chlorophyll measurements the unfiltered sample was filled directly into the 1 cm quartz cuvette, again pre-rinsing was done three times with the unfiltered sample water. Here, we used Milli-Q as a reference blank sample. Fluorescence was determined using a Perkin Elmer LS55 fluorometer. During the FDOM measurements, the excitation spectrum was set from 220 nm to 450 nm at a 5 nm resolution whilst the emission wavelength range was from 240 nm to 560 nm at 0.5 nm resolutions. As for the chlorophyll-a observations, the excitation wavelengths ranged from 440 nm to 480 nm at 5 nm intervals and the emission spectrum ranged from 460 nm to 800 nm in 0.5 nm steps. The provided dataset contains the raw intensity units for each measurement

A thermodynamically motivated formulation of the energy model of semiconductor devices

SIGLEAvailable from TIB Hannover: RR 5549(210)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

On stationary Schroedinger-Poisson equations

We regard the Schroedinger-Poisson system arising from the modelling of an electron gas with reduced dimension in a bounded up to three-dimensional domain and establish the method of steepest descent. The electrostatic potentials of the iteration scheme will converge uniformly on the spatial domain. To get this result we investigate the Schroedinger operator, the Fermi level and the quantum mechanical electron density operator for square integrable electrostatic potentials. On bounded sets of potentials the Fermi level is continuous and bounded, and the electron density operator is monotone and Lipschitz continuous. As a tool we develop a Riesz-Dunford functional calculus for semibounded self-adjoint operators using paths of integration which enclose a real half axis. (orig.)Available from TIB Hannover: RR 5549(66)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Convex analysis of the energy model of semiconductor devices

SIGLEAvailable from TIB Hannover: RR 5549(285)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman