Jochen Wollschläger

Jochen Wollschläger
Carl von Ossietzky Universität Oldenburg · Department of Chemistry and Biology of the Marine Environment (ICBM)

PhD

About

21
Publications
6,238
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243
Citations

Publications

Publications (21)
Article
Full-text available
Coastal observatories are key to improve the understanding of processes within the coastal area and their interactions with regional and global environmental changes. The land-sea transition zone is an essential area that allows research on unique scientific questions under anthropogenic and natural influences. Amid the Wadden Sea UNESCO world natu...
Article
Full-text available
Over the past two decades, robotic technology such as Argo floats have revolutionized operational autonomous measurement of the oceans. Recently, Biogeochemical Argo floats (BGC-Argo floats) have measured optical and biogeochemical quantities down to a depth of 2,000 m. Among these parameters, are measurements of the underwater light field from whi...
Article
Full-text available
As an essential parameter for all kinds of aquatic life, light influences life cycles and the behavior of various marine organisms. However, its primary role is that of a driver for photosynthesis and thus primary production, forming the basis of the marine food web. As a simplification when dealing with light, a common measure (e.g., used in bioge...
Article
Full-text available
Together with scattering, the process of absorption determines the propagation of light within the water column. It is influenced by the concentration and composition of optically active substances (phytoplankton, chromophoric-dissolved organic matter, and non-living particles). For this reason, the absorption coefficients of a water sample can pro...
Article
Full-text available
Natural organic matter (NOM) is a key parameter in aquatic biogeochemical processes. Part of the NOM pool exhibits optical properties, namely absorption and fluorescence. The latter is frequently utilized in laboratory measurements of its dissolved fraction (fluorescent dissolved organic matter, FDOM) through excitation–emission matrix spectroscopy...
Code
This is a collection of MatLab-based scripts and functions for the processing of data measured with the OSCAR (Online Hyperspectral Integrating Cavity Absorption Meter; TriOS GmbH, Germany). They are based on the procedures and equations given in Kirk, J.T., 1997. Point-source integrating-cavity absorption meter: theoretical principles and numerica...
Chapter
The term plankton describes all water-living organisms the inherent movement abilities for which are small compared to the movement of the surrounding water. Strictly speaking, this also includes comprehensively large organisms like jellyfish, but most planktonic organisms are of relatively small size (micrometers to millimeters). Phytoplankton as...
Article
Full-text available
The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as a...
Article
Full-text available
Optically active constituents (OACs) in addition to water molecules attenuate light via processes of absorption and scattering and thereby determine underwater light availability. An analysis of their optical properties helps in determining the contribution of each of these to light attenuation. With an aim to study the bio-optical variability, abs...
Article
Full-text available
Information on recent biomass distribution and biogeography of photosynthetic marine protists with adequate temporal and spatial resolution is urgently needed to better understand the consequences of environmental change for marine ecosystems. Here we introduce and review a molecular-based observation strategy for high-resolution assessment of thes...
Article
Full-text available
To meet the requirements of increasing environmental awareness in aquatic ecosystems, optical techniques offer a fast and reliable opportunity for a wide range of applications providing high-resolution measurements. In this respect, important parameters which have to be addressed include phytoplankton biomass and taxonomic composition, total suspen...
Article
Full-text available
The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example for a heavily used coastal area, and Svalbard as...
Article
In this paper, modernized shipborne procedures are presented to collect and process above-water radiometry for remote sensing applications. A setup of five radiometers and a bidirectional camera system, which provides panoramic sea surface and sky images, is proposed for the collection of high-resolution radiometric quantities. Images from the came...
Article
Full-text available
Investigation of phytoplankton biodiversity, ecology, and biogeography is crucial for understanding marine ecosystems. Research is often carried out on the basis of microscopic observations, but due to the limitations of this approach regarding detection and identification of picophytoplankton (0.2–2 μm) and nanophytoplankton (2–20 μm), these inves...
Data
In this paper, modernized shipborne procedures are presented to collect and process above-water radiometry for remote sensing applications. A setup of five radiometers and a bidirectional camera system, which provides panoramic sea surface and sky images, is proposed for the collection of high-resolution radiometric quantities. Images from the came...
Conference Paper
Full-text available
To meet the requirements of increasing environmental awareness in aquatic ecosystems, optical techniques offer a fast and reliable opportunity for a wide range of application providing spatio-temporal measurements. Within the work package 5 of NeXOS innovative, compact, and cost efficient multifunctional sensor systems for optical measurements of m...
Article
Full-text available
Phytoplankton community analysis is important with respect to natural or human-induced changes in the marine environment. Because of the efforts involved and the limitations of traditional methods, molecular sensing approaches are becoming more popular. Among others, microarray techniques targeting ribosomal 18S sequences have been successfully app...
Article
Full-text available
The concentrations of chlorophyll-a ([chl-a]) and total suspended matter ([TSM]) are important parameters in biological oceanography. [Chl-a] is a commonly used proxy for estimating phytoplankton biomass while [TSM] also includes detrital material and mineral particles and thus influences light attenuation and photosynthetic activity in the water c...
Article
Full-text available
Determination of spectral absorption coefficients in seawater is of interest for biologic oceanographers for various reasons, but faces also several problems, especially if continuous measurements are required. We introduce the flow-through point-source integrating cavity absorption meter (ft-PSICAM) as a new tool for the continuous measurement of...

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Project (1)
Project
Fjords are a type of estuaries with complex dynamic ecosystems. Remote retrieval of bio-optical parameters therefore require a sound understanding of in-situ variability in optical properties.