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| Dissard, Delphine; Reichart, Gert Jan; Menkes, Christophe; Mangeas, Morgan; Frickenhaus, Stephan; Bijma, Jelle. |
| Over the last decades, sea surface temperature (SST) reconstructions based on the Mg∕Ca of foraminiferal calcite have frequently been used in combination with the δ18O signal from the same material to provide estimates of the δ18O of water (δ18Ow), a proxy for global ice volume and sea surface salinity (SSS). However, because of error propagation from one step to the next, better calibrations are required to increase the accuracy and robustness of existing isotope and element to temperature proxy relationships. Towards that goal, we determined Mg∕Ca, Sr∕Ca and the oxygen isotopic composition of Trilobatus sacculifer (previously referenced as Globigerinoides sacculifer) collected from surface waters (0–10 m) along a north–south transect in the eastern basin... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78884/81200.pdf |
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| Wattelez, Guillaume; Dupouy, Cecile; Mangeas, Morgan; Lefevre, Jerome; Touraivane,; Frouin, Robert. |
| Spatial and temporal dynamics of phytoplankton biomass and water turbidity can provide crucial information about the function, health and vulnerability of lagoon ecosystems (coral reefs, sea grasses, etc.). A statistical algorithm is proposed to estimate chlorophyll-a concentration ([chl-a]) in optically complex waters of the New Caledonian lagoon from MODIS-derived remote-sensing reflectance (R-rs). The algorithm is developed via supervised learning on match-ups gathered from 2002 to 2010. The best performance is obtained by combining two models, selected according to the ratio of R-rs in spectral bands centered on 488 and 555 nm: a log-linear model for low [chl-a] (AFLC) and a support vector machine (SVM) model or a classic model (OC3) for high [chl-a].... |
| Tipo: Text |
Palavras-chave: Chlorophyll-a concentration; MODerate resolution Imaging Spectroradiometer (MODIS); Ocean color; Remote sensing; Statistical algorithm; Oligotrophic waters; New Caledonia; Coral lagoon. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00481/59309/62060.pdf |
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| Receveur, Aurore; Kestenare, Elodie; Allain, Valerie; Ménard, Frédéric; Cravatte, Sophie; Lebourges-dhaussy, Anne; Lehodey, Patrick; Mangeas, Morgan; Smith, Neville; Radenac, Marie-hélène; Menkes, Christophe. |
| Acoustic data are invaluable information sources for characterizing the distribution and abundance of mid-trophic-level organisms (micronekton). These organisms play a pivotal role in the ecosystem as prey of top predators and as predators of low-trophic-level organisms. Although shipboard-ADCP (acoustic Doppler current profiler) acoustic backscatter signal intensity cannot provide an absolute biomass estimate, it may be a useful proxy to investigate variability in the distribution and relative density of micronekton. This study used acoustic recordings data spread across 19 years (1999–2017) from 54 ADCP cruises in New Caledonia’s subtropical EEZ (exclusive economic zone) to assess seasonal and interannual variabilities and spatial distribution of... |
| Tipo: Text |
Palavras-chave: Micronekton; Southwest Pacific ocean; SEAPODYM; Acoustic; Ecosystem. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72078/70794.pdf |
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