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| Haëntjens, Nils; Della Penna, Alice; Briggs, Nathan; Karp‐boss, Lee; Gaube, Peter; Claustre, Hervé; Boss, Emmanuel. |
| During the North Atlantic Aerosols and Ecosystems Study (NAAMES) in the western North Atlantic (NAAMES), float‐based profiles of fluorescent dissolved organic matter (FDOM) and backscattering exhibited distinct spike layers at ~300 m. The locations of the spikes were at depths similar or shallower to where a ship‐based scientific echo sounder identified layers of acoustic backscatter, an Underwater Vision Profiler (UVP) detected elevated concentration of zooplankton, and mesopelagic fish were sampled by a mesopelagic net tow. The collocation of spike layers in bio‐optical properties with mesopelagic organisms suggests that some can be detected with float‐based bio‐optical sensors. This opens the door to the investigation of such aggregations/layers in... |
| Tipo: Text |
Palavras-chave: BGC-Argo; Diel vertical migration; Mesopelagic organism; Scattering layers. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72121/70869.pdf |
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| Xing, Xiaogang; Briggs, Nathan; Boss, Emmanuel; Claustre, Herve. |
| In situ chlorophyll fluorometers have been used to quantify the distribution of chlorophyll concentration in natural waters for decades. However, chlorophyll fluorescence is depressed during daylight hours due to non-photochemical quenching (NPQ). Corrections attempted to date have provided improvement but still remain unsatisfactory, often over-estimating the expected value. In this study. we examine the relationship between NPQ and instantaneous Photosynthetically Active Radiation (iPAR) using field data from BGC-Argo floats equipped with Chlorophyll-alpha fluorometers and radiometers. This analysis leads to an improved NPQ correction that incorporates both iPAR and mixed layer depth (MLD) and is validated against data collected at sunrise or sunset. The... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00640/75204/75335.pdf |
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| Roesler, Collin; Uitz, Julia; Claustre, Herve; Boss, Emmanuel; Xing, Xiaogang; Organelli, Emanuele; Briggs, Nathan; Bricaud, Annick; Schmechtig, Catherine; Poteau, Antoine; D'Ortenzio, Fabrizio; Ras, Josephine; Drapeau, Susan; Haentjens, Nils; Barbieux, Marie. |
| Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease of use, size, power consumption, and relatively low price. While in situ chlorophyll a (Chl) fluorescence is proxy for Chl a concentration, and hence phytoplankton biomass, there exist large natural variations in the relationship between in situ fluorescence and extracted Chl a concentration. Despite this large natural variability, we present here a global validation data set for the WET Labs Environmental Characterization Optics (ECO) series chlorophyll fluorometers that suggests a factor of 2 overestimation in the factory calibrated Chl a estimates for this specific manufacturer and series of sensors. We base these results on... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00384/49552/50046.pdf |
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| Organelli, Emanuele; Barbieux, Marie; Claustre, Herve; Schmechtig, Catherine; Poteau, Antoine; Bricaud, Annick; Boss, Emmanuel; Briggs, Nathan; Dall'Olmo, Giorgio; D'Ortenzio, Fabrizio; Leymarie, Edouard; Mangin, Antoine; Obolensky, Grigor; Penkerc'H, Christophe; Prieur, Louis; Roesler, Collin; Serra, Romain; Uitz, Julia; Xing, Xiaogang. |
| Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world's oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradiance at three wavelengths, and photosynthetically available radiation) variables are collected in the upper 1000 m every 1 to 10 days. The database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically developed procedures and its time series is quality-assessed to identify issues... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00662/77389/79010.pdf |
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