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11 pages, 3 figures, supporting information https://doi.org/10.1021/acs.est.0c00695, We present shipborne measurements of size-resolved concentrations of aerosol components across ocean waters next to the Antarctic Peninsula, South Orkney Islands, and South Georgia Island, evidencing aerosol features associated with distinct eco-regions. Nonmethanesulfonic acid Water-Soluble Organic Matter (WSOM) represented 6–8% and 11–22% of the aerosol PM1 mass originated in open ocean (OO) and sea ice (SI) regions, respectively. Other major components included sea salt (86–88% OO, 24–27% SI), non sea salt sulfate (3–4% OO, 35–40% SI), and MSA (1–2% OO, 11–12% SI). The chemical composition of WSOM encompasses secondary organic components with diverse behaviors: while alkylamine concentrations were higher in SI air masses, oxalic acid showed higher concentrations in the open ocean air. Our online single-particle mass spectrometry data exclude a widespread source from sea bird colonies, while the secondary production of oxalic acid and sulfur-containing organic species via cloud processing is suggested. We claim that the potential impact of the sympagic planktonic ecosystem on aerosol composition has been overlooked in past studies, and multiple eco-regions act as distinct aerosol sources around Antarctica, The study was supported by the Spanish Ministry of Economy through project BIO-NUC (CGL2013-49020-R), PI-ICE (CTM2017–89117-R) and the Ramon y Cajal fellowship (RYC-2012-11922), and by the EU though the FP7-PEOPLE-2013-IOF programme (Project number 624680, MANU – Marine Aerosol NUcleations), all to M.D., and PEGASO (CTM2012-37615) to R.S., With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Dimethyl sulfide (DMS) is emitted by phytoplankton species in the oceans and constitutes the largest source of naturally emitted sulfur to the atmosphere. The climate impact of secondary particles, formed through the oxidation of DMS by hydroxyl radicals, is still elusive. This study investigates the hygroscopicity and cloud condensation nuclei activity of such particles and discusses the results in relation to their chemical composition. We show that mean hygroscopicity parameters, κ, during an experiment for particles of 80 nm in diameter range from 0.46 to 0.52 or higher, as measured at both sub- and supersaturated water vapour conditions. Ageing of the particles leads to an increase in κ from, for example, 0.50 to 0.58 over the course of 3 h (Exp. 7). Aerosol mass spectrometer measurements from this study indicate that this change most probably stems from a change in chemical composition leading to slightly higher fractions of ammonium sulfate compared to methanesulfonic acid (MSA) within the particles with ageing time. Lowering the temperature to 258 K increases κ slightly, particularly for small particles. These κ values are well comparable to previously reported model values for MSA or mixtures between MSA and ammonium sulfate. Particle nucleation and growth rates suggest a clear temperature dependence, with slower rates at cold temperatures. Quantum chemical calculations show that gas-phase MSA clusters are predominantly not hydrated, even at high humidity conditions, indicating that their gas-phase chemistry should be independent of relative humidity.

G. E. Hutchinson raised the paradox of how a number of phytoplankton species competing for the same resources are able to coexist in a relatively isotropic environment. As a key for solving the paradox, we focused on the limiting similarity which prohibits the coexistence of similar species. We expected that the limiting similarity will be mitigated by some factors which are not represented in traditional theoretical studies but can be represented if we use a three-dimensional (3D) model. The use of a 3D model enables us to explore the limiting similarity without using the controversial assumption connecting niche overlap with the competitive exclusion in previous theoretical studies. Furthermore, while constant or no dispersion is given in theoretical studies, it is explicitly represented in a 3D model. The coexistence of similar species in 3D environments was explored by dividing a target persistent species in a quasi-equilibrium community into 80 subspecies, which were slightly different from one another at the optimum temperature for population growth. In the experiments, we found cases in which several dozens of species having nearly-overlapping niches coexist stably at a point for over 80 years. The comparison of experiments with and without dispersion by oceanic currents revealed that dispersion negates the progress of competitive exclusion or significantly delays the exclusion. The result that species having nearly-overlapping niches are able to coexist also highlights the crucial role of the specific rate in determining the number of coexisting species. If the number of coexisting species is not determined by the limiting similarity, it will be determined by the frequency of speciation events, as in the neutral theory.

19 pages, 21 figures, 1 table, Oceanic turbulent flows develop complicated patterns, with eddies, filaments and shear currents. Although usually referred as chaotic, their inner organization is strongly hierarchical: turbulent flows develop cascades, which transfer properties such as energy or scalar density from larger to smaller scales. In this work, we present a novel algorithm based on the cascade and able to fill data gaps in satellite images (particularly, chlorophyll concentration maps). The first step is to show that cascade processes for chlorophyll-a concentration images take a simple, explicit form when an appropriate wavelet (here Battle–Lemarié of order 3) representation is used. A reconstruction algorithm exploiting the cascade structure is then given with a detailed description. We discuss the validity and quality of this algorithm when applied to SeaWiFS and MODIS-Aqua ocean color images. An application to merging data from multiple satellite missions is presented together with a demonstration of the benefit of this algorithm over two other merging methods, Financial support for this work was provided by the CNES funding to LEGOS. A. T. is contracted under the Ramón y Cajal program by the Spanish Ministry of Education. C. P. was funded by a CIFRE CLS/LEGOS-CNRS PhD fellowship. This work has been performed within the context of the European Integrated Project MERSEA and as a contribution to the CSIC OCEANTECH project (PIF-2006). Ocean color data were produced by the SeaWiFS project at GSFC and obtained from the DAAC