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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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| Schulien, Jennifer A.; Della Penna, Alice; Gaube, Peter; Chase, Alison P.; Haëntjens, Nils; Graff, Jason R.; Hair, Johnathan W.; Hostetler, Chris A.; Scarino, Amy Jo; Boss, Emmanuel S.; Karp-boss, Lee; Behrenfeld, Michael J.. |
| Changes in airborne high spectral resolution lidar (HSRL) measurements of scattering, depolarization, and attenuation coincided with a shift in phytoplankton community composition across an anticyclonic eddy in the North Atlantic. We normalized the total depolarization ratio (δ) by the particulate backscattering coefficient (bbp) to account for the covariance in δ and bbp that has been attributed to multiple scattering. A 15% increase in δ/bbp inside the eddy coincided with decreased phytoplankton biomass and a shift to smaller and more elongated phytoplankton cells. Taxonomic changes (reduced dinoflagellate relative abundance inside the eddy) were also observed. The δ signal is thus potentially most sensitive to changes in phytoplankton shape because... |
| Tipo: Text |
Palavras-chave: HSRL; Depolarization; Backscatter; Phytoplankton community composition; Eddy. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75313/75809.pdf |
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| Freney, Evelyn; Sellegri, Karine; Nicosia, Alessia; Trueblood, Jonathan T; Rinaldi, Matteo; Williams, Leah R; Prévôt, André Sh; Thyssen, Melilotus; Gregori, Gerald; Haëntjens, Nils; Dinasquet, Julie; Obernosterer, Ingrid; Van Wambeke, France; Engel, Anja; Zancker, Birthe; Desboeufs, Karine; Asmi, Eija; Timmonen, Hilka; Guieu, Cécile. |
| The organic mass fraction from sea spray aerosol (SSA) is currently a subject of intense research. The majority of this research is dedicated to measurements in ambient air, although recently a small number of studies have additionally focused on nascent sea spray aerosol. This work presents measurements collected during a five-week cruise in May and June 2017 in the central and western Mediterranean Sea, an oligotrophic marine region with low phytoplankton biomass. Surface seawater was continuously pumped into a bubble bursting apparatus to generate nascent sea spray aerosol. Size distributions were measured with a differential mobility particle sizer (DMPS). Chemical characterization of the submicron aerosol was performed with a time of flight aerosol... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00688/80017/82995.pdf |
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| Sellegri, Karine; Nicosia, Alessia; Freney, Evelyn; Uitz, Julia; Thyssen, Melilotus; Grégori, Gérald; Engel, Anja; Zäncker, Birthe; Haëntjens, Nils; Mas, Sébastien; Picard, David; Saint-macary, Alexia; Peltola, Maija; Rose, Clémence; Trueblood, Jonathan; Lefevre, Dominique; D’anna, Barbara; Desboeufs, Karine; Meskhidze, Nicholas; Guieu, Cécile; Law, Cliff S.. |
| One pathway by which the oceans influence climate is via the emission of sea spray that may subsequently influence cloud properties. Sea spray emissions are known to be dependent on atmospheric and oceanic physicochemical parameters, but the potential role of ocean biology on sea spray fluxes remains poorly characterized. Here we show a consistent significant relationship between seawater nanophytoplankton cell abundances and sea-spray derived Cloud Condensation Nuclei (CCN) number fluxes, generated using water from three different oceanic regions. This sensitivity of CCN number fluxes to ocean biology is currently unaccounted for in climate models yet our measurements indicate that it influences fluxes by more than one order of magnitude over the range of... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00669/78077/80312.pdf |
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