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| Launeau, Patrick; Giraud, Manuel; Robin, Marc; Baltzer, Agnes. |
| In shoreline monitoring, only topo-bathymetric light detection and ranging (LiDAR) can map large corridors from aerial dunes to sandbanks in shallow water. Increasing turbidity masking the formation of 532 nm laser beam echoes on the sea bed makes this challenging. Full-waveform recording all the laser beam damping functions, a turbid water column can be seen as an accumulation of layers forming a single continuum and a distinction can be made between signals ending at the bottom down to a depth of 10 m. In practice full-waveforms are converted by laser beam tracing an image cube with a grid of 1-m-wide pixels and a 0.15 m range resolution storing the mean intensities returned along incident angle. The first derivative of a wide Gaussian filter serves to... |
| Tipo: Text |
Palavras-chave: Full-waveform; Airborne LiDAR; Bathymetry; Shoreline monitoring; Turbidity. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00476/58745/61270.pdf |
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| Choquel, Constance; Geslin, Emmanuelle; Metzger, Edouard; Filipsson, Helena L.; Risgaard-petersen, Nils; Launeau, Patrick; Giraud, Manuel; Jauffrais, Thierry; Jesus, Bruno; Mouret, Aurélia. |
| Oxygen availability impacts the marine nitrogen cycle at a range of spatial and temporal scales. Invasive organisms have shown to sustainably affect sediment geochemistry and benthic ecology. Nonionella sp. T1 was recently described as an invasive benthic foraminifer in the North Sea region. Here, we demonstrate the impact of this denitrifying species on the foraminifera fauna and the nitrogen cycle of the Gullmar Fjord (Sweden). The foraminifera contribution to benthic denitrification was estimated by coupling living foraminifera micro-distribution, denitrification rate measurement and sedimentary nitrate 2D distribution. Nonionella sp. T1 dominated the foraminifera fauna and could denitrify up to 50–100 % of nitrate porewater in oxygenated bottom waters... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00643/75482/76327.pdf |
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| Clement, Jean-philippe; Caroff, Martial; Dudoignon, Patrick; Launeau, Patrick; Bohn, Marcel; Cotten, Joseph; Blais, Sylvain; Guille, Gérard. |
| This paper reports new field observations and new petrological, textural and geochemical data on two gabbroic intrusions and one pegmatoid dyke from the French Polynesian islands Maupiti and Bora Bora, respectively. Olivine crystals from the Faataufi and Barque de Hiro gabbros (Maupiti) include High Temperature Iddingsite (HTI), exhibiting three distinct morphological facies. Chemical and crystallographical data performed by electron microprobe, scanning microscope, X-ray diffractometry and Near InfraRed spectroscopy show that HTI results from modifications of olivine structure through intense hydroxylation and Fe-oxidation. The HTI-free 120 m-wide Cloche de Hiro dyke (Bora Bora) exhibits a textural zonation from heterogranular/intergranular gabbro... |
| Tipo: Text |
Palavras-chave: Society Islands; French Polynesia; Pegmatoid; Vapor differentiation; Olivine; Gabbros. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2999.pdf |
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