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  • Wiley  (43)
  • Frontiers Media  (19)
  • ZBW - Deutsche Zentralbibliothek für Wirtschaftswissenschaften, Leibniz-Informationszentrum Wirtschaft Kiel, Hamburg
  • 2015-2019  (43)
  • 2010-2014  (19)
  • 1
  • 2
  • 3
    Publication Date: 2022-05-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lombard, F., Boss, E., Waite, A. M., Vogt, M., Uitz, J., Stemmann, L., Sosik, H. M., Schulz, J., Romagnan, J., Picheral, M., Pearlman, J., Ohman, M. D., Niehoff, B., Moeller, K. M., Miloslavich, P., Lara-Lpez, A., Kudela, R., Lopes, R. M., Kiko, R., Karp-Boss, L., Jaffe, J. S., Iversen, M. H., Frisson, J., Fennel, K., Hauss, H., Guidi, L., Gorsky, G., Giering, S. L. C., Gaube, P., Gallager, S., Dubelaar, G., Cowen, R. K., Carlotti, F., Briseno-Avena, C., Berline, L., Benoit-Bird, K., Bax, N., Batten, S., Ayata, S. D., Artigas, L. F., & Appeltans, W. Globally consistent quantitative observations of planktonic ecosystems. Frontiers in Marine Science, 6, (2019):196, doi:10.3389/fmars.2019.00196.
    Description: In this paper we review the technologies available to make globally quantitative observations of particles in general—and plankton in particular—in the world oceans, and for sizes varying from sub-microns to centimeters. Some of these technologies have been available for years while others have only recently emerged. Use of these technologies is critical to improve understanding of the processes that control abundances, distributions and composition of plankton, provide data necessary to constrain and improve ecosystem and biogeochemical models, and forecast changes in marine ecosystems in light of climate change. In this paper we begin by providing the motivation for plankton observations, quantification and diversity qualification on a global scale. We then expand on the state-of-the-art, detailing a variety of relevant and (mostly) mature technologies and measurements, including bulk measurements of plankton, pigment composition, uses of genomic, optical and acoustical methods as well as analysis using particle counters, flow cytometers and quantitative imaging devices. We follow by highlighting the requirements necessary for a plankton observing system, the approach to achieve it and associated challenges. We conclude with ranked action-item recommendations for the next 10 years to move toward our vision of a holistic ocean-wide plankton observing system. Particularly, we suggest to begin with a demonstration project on a GO-SHIP line and/or a long-term observation site and expand from there, ensuring that issues associated with methods, observation tools, data analysis, quality assessment and curation are addressed early in the implementation. Global coordination is key for the success of this vision and will bring new insights on processes associated with nutrient regeneration, ocean production, fisheries and carbon sequestration.
    Description: Much of this manuscript flows from discussions of the authors with the members of SCOR working groups 150 (TOMCAT) and 154 (P-OBS) as well as discussions with the greater community in various GOOS workshops. We also thank Mike Sieracki, Cabell Davis, Daniele Iudicone, Eric Karsenti, Sebastien Colin, Colomban de Vargas, Ulf Riebesell, Fabrice Not, David Checkley, George Jackson, Cédric Guigand, Ed Urban, Frank Muller-Karger, Sanae Chiba and Daniel Dunn, who contributed to the initial abstracts to OceanObs'19. FL is supported by the Institut Universitaire de France. EB is supported by the NASA biology and biogeochemistry program. RKi and HH were supported by the German Science Foundation through the Collaborative Research Center 754 ‘Climate-Biogeochemistry Interactions in the Tropical Ocean’. SDA acknowledges the CNRS for her sabbatical year as visiting researcher at ISYEB on the use of genomics and next generation sequencing for plankton studies. HS acknowledges support from the Simons Foundation, the U.S. National Science Foundation, and the U.S. National Oceanic and Atmospheric Administration through the Cooperative Institute for the North Atlantic Region. FL and EB contribution was also inspired by their years of work within the Tara Expeditions initiative.
    Keywords: plankton ; imaging ; OceanObs ; autonomous platforms ; global observing ; EOVs ; ECVs
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 4
    Publication Date: 2013-02-16
    Description: [1]  Phytoplankton are an important component of the oceanic carbon cycle. Yet, due to methodological constraints, the carbon biomass of phytoplankton is poorly characterised. To address this limitation, we have explored the bio-optical relationship between in-situ measurements of the particle backscattering coefficient at 470 nm, b bp (470), and the phytoplankton carbon concentration for cells with diameter less than 20  μ m (C f ). We found a significant relationship between b bp (470) and C f for Atlantic oceanic waters with chlorophyll-a concentrations less than 0.4 mg m -3 (or b bp (470) 〈 0.003 m -1 ). This relationship could be used to estimate C f from data collected by in-situ autonomous platforms and from remote sensing of ocean colour.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 5
    Publication Date: 2013-02-13
    Description: [1]  The Dead Sea, located in the rift valley between Jordan and Israel, is a hypersaline lake, resulting in unique biogeochemistry and optical properties. In the spring of 2004 we conducted two days of physical and optical measurements in the lake. Because of the significant effect of dissolved salts onthe optical propertiesof water,our analysis required a novel processing approach to obtain dissolved and total inherent optical properties from the measurements. In addition, we show that the lake's salinity can be estimated from measurements of hyper-spectral absorption or attenuation spectra in the red and infrared parts of the spectrum, using published values of specific absorption of dissolved NaCl, despite the fact that the lake's salt chemistry is complex. In situ observations demonstrated that the lake has a two-layer structure with a warm and more turbid layer at the top 20-30 m and a clearer colder layer below. Both the particulate and dissolved absorption are well approximated by exponentially decreasing functions with the spectral slope of the particulate absorption about half that of the dissolved fraction and consistent with other aquatic environments. Both have relatively low and similar magnitudes in the blue (O(0.15 m -1 )). Mean particle size was observed to increase with depth consistent with precipitating salt crystals (observed in past campaigns) shown here toplay a major role in the lake's optical properties.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 6
    Publication Date: 2011-11-24
    Description: A unique time series of moored bio-optical measurements documented the 2004 spring-summer bloom in the southern Labrador Sea. In situ and satellite chlorophyll data show that chlorophyll levels in the 2004 bloom were at the upper end of those typically observed in this region. Satellite chlorophyll and profiling float temperature/salinity data show that the main bloom, which typically peaks in June/July, is often preceded by ephemeral mixed layer shoaling and a lesser, short-lived bloom in May; this was the case in 2004. The particulate backscatter to beam attenuation ratio (bbp[470 nm]/Cp[660 nm]) showed peaks in the relative abundance of small particles at bloom initiation and during the decline of the bloom, while larger particles dominated during the bloom. Chlorophyll/Cp and bbp/chlorophyll were correlated with carbon export and dominated by changes in the pigment per cell associated with lower light levels due to enhanced attenuation of solar radiation during the bloom. An NPZ (nutrients, phytoplankton, zooplankton) model captured the phytoplankton bloom and an early July peak in zooplankton. Moored acoustic Doppler current profiler (ADCP) data showed an additional mid-June peak in zooplankton biomass which was attributed to egg-laying copepods. The data reported here represent one of the few moored time series of Cp, bbp and chlorophyll extending over several months in an open ocean region. Interpretation of data sets such as this will become increasingly important as these deployments become more commonplace via ocean observing systems. Moreover, these data contribute to the understanding of biological-physical coupling in a biogeochemically important, yet poorly studied region.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 7
    Publication Date: 2011-02-16
    Description: The goal of this study was to test the hypothesis that the aggregated state of natural marine particles constrains the sensitivity of optical beam attenuation to particle size. An instrumented bottom tripod was deployed at the 12-m node of the Martha's Vineyard Coastal Observatory to monitor particle size distributions, particle size-versus-settling-velocity relationships, and the beam attenuation coefficient (cp) in the bottom boundary layer in September 2007. An automated in situ filtration system on the tripod collected 24 direct estimates of suspended particulate mass (SPM) during each of five deployments. On a sampling interval of 5 min, data from a Sequoia Scientific LISST 100x Type B were merged with data from a digital floc camera to generate suspended particle volume size distributions spanning diameters from approximately 2 μm to 4 cm. Diameter-dependent densities were calculated from size-versus-settling-velocity data, allowing conversion of the volume size distributions to mass distributions, which were used to estimate SPM every 5 min. Estimated SPM and measured cp from the LISST 100x were linearly correlated throughout the experiment, despite wide variations in particle size. The slope of the line, which is the ratio of cp to SPM, was 0.22 g m−2. Individual estimates of cp:SPM were between 0.2 and 0.4 g m−2 for volumetric median particle diameters ranging from 10 to 150 μm. The wide range of values in cp:SPM in the literature likely results from three factors capable of producing factor-of-two variability in the ratio: particle size, particle composition, and the finite acceptance angle of commercial beam-transmissometers.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 8
    Publication Date: 2019
    Description: Abstract Two Bio‐Argo floats measured the concentration of chlorophyll‐a, the backscattering coefficient, the fluorescence of humic‐like dissolved organic matter, dissolved oxygen, and temperature and salinity in the northern and central basins of the South China Sea for over 2 years. Temporal evolutions of bio‐optical properties were analyzed at surface, subsurface, and in the whole water column, respectively. It was found that (1) The seasonal variability of the surface chlorophyll‐a was highly controlled by photoacclimation, especially in the central basin; (2) backscattering in the upper 150 m was nearly constant, exhibiting no distinct seasonality; (3) with vertical mixing, particles from the deep chlorophyll maxima were entrained into the mixed layer resulting in enhanced surface chlorophyll during the early winter. This phenomenon may mislead a study based on satellite data which is likely to interpret it as blooming rather than a redistribution of phytoplankton within the water column; (4) analysis of a winter bloom and an anticyclonic eddy reveal that physical entrainment and biological photoacclimation modulated the vertical distributions of chlorophyll‐a and particles and potentially also changes of phytoplankton community composition; and (5) fluorescent dissolved organic matter was found to be highly coupled to phytoplankton dynamics in both basins, with a maximum (after removing the contribution of physical convective mixing) located at the depth of chlorophyll‐a subsurface maximum.
    Print ISSN: 2169-9275
    Electronic ISSN: 2169-9291
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 9
    Publication Date: 2013-11-28
    Description: [1]   Chiswell [2013] suggests that some of the conclusions drawn by Behrenfeld et al . [2013] are likely erroneous because of (1) the method used to calculate specific net biomass accumulation rates ( r ; d -1 ) over the seasonal cycle, (2) inconsistencies in the calculation of r and phytoplankton specific cell division rate, μ (d -1 ), and (3) uncertainties in the extrapolation of satellite data to the depth of the seasonal thermocline. Each of these concerns is addressed in the following subsections. We begin with a simple culture-based analogy that clarifies why switching between concentration-based and inventory-based expressions is required for calculating r when the mixed layer varies between shoaling and deepening conditions. This analogy is followed by a more specific mathematical treatment. We then explain why our previous comparisons between r and μ provide a conservative estimate of predator-prey coupling, followed by a discussion of uncertainties in satellite-based assessments of mixed layer phytoplankton biomass.
    Print ISSN: 0886-6236
    Electronic ISSN: 1944-9224
    Topics: Biology , Chemistry and Pharmacology , Geography , Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 10
    Publication Date: 2019
    Description: Abstract Biogeochemical Argo floats, profiling to 2,000‐m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM). The goal is 200 floats by 2020, to provide the first full set of annual cycles of carbon, oxygen, nitrate, and optical properties across multiple oceanographic regimes. Building from no prior coverage to a sparse array, deployments are based on prior knowledge of water mass properties, mean frontal locations, mean circulation and eddy variability, winds, air‐sea heat/freshwater/carbon exchange, prior Argo trajectories, and float simulations in the Southern Ocean State Estimate and Hybrid Coordinate Ocean Model (HYCOM). Twelve floats deployed from the 2014–2015 Polarstern cruise from South Africa to Antarctica are used as a test case to evaluate the deployment strategy adopted for SOCCOM's 20 deployment cruises and 126 floats to date. After several years, these floats continue to represent the deployment zones targeted in advance: (1) Weddell Gyre sea ice zone, observing the Antarctic Slope Front, and a decadally‐rare polynya over Maud Rise; (2) Antarctic Circumpolar Current (ACC) including the topographically steered Southern Zone chimney where upwelling carbon/nutrient‐rich deep waters produce surprisingly large carbon dioxide outgassing; (3) Subantarctic and Subtropical zones between the ACC and Africa; and (4) Cape Basin. Argo floats and eddy‐resolving HYCOM simulations were the best predictors of individual SOCCOM float pathways, with uncertainty after 2 years of order 1,000 km in the sea ice zone and more than double that in and north of the ACC.
    Print ISSN: 2169-9275
    Electronic ISSN: 2169-9291
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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