Rüdiger Röttgers

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Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is the major hub of oceanic nutrient distribution, selective(More)
Determination of particulate absorption in natural waters is often made by measuring the transmittance of samples on glass-fiber filters with the so-called quantitative filter technique (QFT). The accuracy of this technique is limited due to variations in the optical properties of the sample/filter composite, and due to uncertainties in the path-length(More)
Continuous pulse amplitude–modulated (PAM) fluorescence measurements were performed in situ under natural irradiances for colonies of the coral Stylophora pistillata growing in shallow (2 m) and deeper (11 m) waters of the Red Sea. The effective quantum yield (DF/F ) showed a diurnal pattern inversely related to that of the incident 9 m downwelling(More)
Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncertain. Here(More)
The extent of light absorption in the near-infrared spectral region (NIR; 700–900 nm) of natural suspended particles was investigated by determining the absorption and mass-specific absorption coefficients of samples from different environments: river, coastal waters, tropical lagoon, and oceanic waters. Large amounts of sample were collected onto(More)
T. Dickey, M. L. Banner, P. Bhandari, T. Boyd, L. Carvalho, G. Chang, Y. Chao, H. Czerski, M. Darecki, C. Dong, D. Farmer, S. Freeman, J. Gemmrich, P. Gernez, N. Hall-Patch, B. Holt, S. Jiang, C. Jones, G. Kattawar, D. LeBel, L. Lenain, M. Lewis, Y. Liu, L. Logan, D. Manov, W. K. Melville, M. A. Moline, R. Morison, F. Nencioli, W. S. Pegau, B. Reineman, I.(More)
The emergence of hyperspectral optical satellite sensors for ocean observation provides potential for more detailed information from aquatic ecosystems. The German hyperspectral satellite mission EnMAP (enmap.org) currently in the production phase is supported by a project to explore the capability of using EnMAP data and other future hyperspectral data(More)
The light absorption coefficient of water is dependent on temperature and concentration of ions, i.e. the salinity in seawater. Accurate knowledge of the water absorption coefficient, a, and/or its temperature and salinity correction coefficients, Ψ(T) and Ψ(S), respectively, is essential for a wide range of optical applications. Values are available from(More)
The recent development of inexpensive, compact hyperspectral transmissometers broadens the research capabilities of oceanographic applications. These developments have been achieved by incorporating technologies such as micro-spectrometers as detectors as well as light emitting diodes (LEDs) as light sources. In this study, we evaluate the performance of(More)