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Lei S, Xu J, Li Y, Li L, Lyu H, Liu G, Chen Y, Lu C, Tian C, Jiao W. A semi-analytical algorithm for deriving the particle size distribution slope of turbid inland water based on OLCI data: A case study in Lake Hongze. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 270:116288. [PMID: 33352484 DOI: 10.1016/j.envpol.2020.116288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
The particle size distribution (PSD) slope (ξ) can indicate the predominant particle size, material composition, and inherent optical properties (IOPs) of inland waters. However, few semi-analytical methods have been proposed for deriving ξ from the surface remote sensing reflectance due to the variable optical state of inland waters. A semi-analytical algorithm was developed for inland waters having a wide range of turbidity and ξ in this study. Application of the proposed model to Ocean and Land Color Instrument (OLCI) imagery of the water body resulted in several important observations: (1) the proposed algorithm (754 nm and 779 nm combination) was capable of retrieving ξ with R2 being 0.72 (p < 0.01, n = 60), and MAPE and RMSE being 4.37% and 0.22 (n = 30) respectively; (2) the ξ in HZL was lower in summer than other seasons during the period considered, this variation was driven by the phenological cycle of algae and the runoff caused by rainfall; (3) the band optimization proposed in this study is important for calculating the particle backscattering slope (η) and deriving ξ because it is feasible for both algae dominant and sediment governed turbid inland lakes. These observations help improve our understanding of the relationship between IOPs and ξ, which are affected by different bio-optic processes and algal phenology in the lake environment.
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Affiliation(s)
- Shaohua Lei
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Key Laboratory of Virtual Geographical Environment of Ministry of Education, School of Geography, Nanjing Normal University, Nanjing, 210023, China; Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), IN, 46202, USA
| | - Jie Xu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Key Laboratory of Virtual Geographical Environment of Ministry of Education, School of Geography, Nanjing Normal University, Nanjing, 210023, China
| | - Yunmei Li
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Key Laboratory of Virtual Geographical Environment of Ministry of Education, School of Geography, Nanjing Normal University, Nanjing, 210023, China.
| | - Lin Li
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), IN, 46202, USA
| | - Heng Lyu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Key Laboratory of Virtual Geographical Environment of Ministry of Education, School of Geography, Nanjing Normal University, Nanjing, 210023, China
| | - Ge Liu
- Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Yu Chen
- Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing, 100094, China
| | - Chunyan Lu
- College of Computer and Information Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Chao Tian
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), IN, 46202, USA
| | - Wenzhe Jiao
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), IN, 46202, USA
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2
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Zhai S, Twardowski M, Hedley JD, McFarland M, Nayak AR, Moore T. Optical backscattering and linear polarization properties of the colony forming cyanobacterium Microcystis. OPTICS EXPRESS 2020; 28:37149-37166. [PMID: 33379554 PMCID: PMC7771895 DOI: 10.1364/oe.405871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/02/2020] [Accepted: 10/25/2020] [Indexed: 06/12/2023]
Abstract
Light scattering characteristics of the cyanobacterium Microcystis are investigated with numerical models for sphere aggregates. During summer bloom seasons, Microcystis is prevalent in many inland waters across the globe. Monitoring concentrations with remote sensing techniques requires knowledge of the inherent optical properties (IOPs), especially the backscattering properties of Microcystis cells and colonies in natural settings. In situ measurements in waters dominated by Microcystis blooms have previously detected extremely high backscattering ratios, i.e., bb/b>0.043 at 443 nm [1], the highest to our knowledge in the natural environment. These highbb/bvalues could hold promise as a diagnostic tool in identifying and monitoring Microcystis using optical approaches. However, it has been unclear how this type of optically 'soft' organic particle can generate such highbb/bvalues. In this study, the Multiple Sphere T-matrix (MSTM) model is used to calculate the IOPs of model colonies, including bb/b. Colony sizes in the model ranged from several cells to several hundred and both colony packing density and cell gas vacuole content were varied. Results are compared with model results for equivalent-volume spheres (EVS) and direct in situ measurements. Colony formation was required in the modeling to reproduce the high bb/bconsistent with in situ measurements. The combination of moderate to very dense colony (packing density >30%) and high gas vacuole content in individual cells (volume percentage >20%) was the most favorable condition leading to rapid increases in bb/bwith increasing number of cells Ncell of the colony. Significant linear correlations were observed betweenbb/b and Ncell1/3 for these colonies, wherebb/b increased beyond 0.04 once cell number reached about 1000 cells in the case with the most densely packed cells and highest gas vacuole content. Within commonly observed colony sizes (Ncell <106), colonies with high gas vacuole content exhibited bb/bvalues up to 0.055, consistent with direct measurements from Lake Erie. Polarized scattering was also of interest as a diagnostic tool, particularly with future Earth-orbiting polarimeters being deployed for the NASA Plankton, Aerosols, Cloud, ocean Ecosystem (PACE) mission. The Degree of Linear Polarization (DoLP), expressed by the ratio of two Mueller matrix elements-P12/P11, decreased with increasing colony cell number for Microcystis. Another ratio of two Mueller matrix elementsP22/P11, an index for nonsphericity, also decreased with increasing colony size. In addition to higher relative backscattering, greater colony packing density and larger gas vacuole sizes both led to lower DoLP peak magnitude and lowerP22/P11. An optical opposition feature due to constructive phase interference that was observed previously for cosmic dusts is also present for these modeled colonies, manifested by a narrow intensity peak and negative polarization dip near exact backscattering direction, gradually forming as colony size increases.
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Affiliation(s)
- Siyao Zhai
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA
| | - Michael Twardowski
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - John D. Hedley
- Numerical Optics Ltd., 19 West Street, Witheridge, Tiverton, Devon EX16 8AA, UK
| | - Malcolm McFarland
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA
| | - Aditya R. Nayak
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Timothy Moore
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL 34946, USA
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Organelli E, Dall'Olmo G, Brewin RJW, Tarran GA, Boss E, Bricaud A. The open-ocean missing backscattering is in the structural complexity of particles. Nat Commun 2018; 9:5439. [PMID: 30575718 PMCID: PMC6303329 DOI: 10.1038/s41467-018-07814-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 11/15/2018] [Indexed: 11/16/2022] Open
Abstract
Marine microscopic particles profoundly impact global biogeochemical cycles, but our understanding of their dynamics is hindered by lack of observations. To fill this gap, optical backscattering measured by satellite sensors and in-situ autonomous platforms can be exploited. Unfortunately, these observations remain critically limited by an incomplete mechanistic understanding of what particles generate the backscattering signal. To achieve this understanding, optical models are employed. The simplest of these models—the homogeneous sphere—severely underestimates the measured backscattering and the missing signal has been attributed to submicron particles. This issue is known as the missing backscattering enigma. Here we show that a slightly more complex optical model—the coated sphere—can predict the measured backscattering and suggests that most of the signal comes from particles >1 µm. These findings were confirmed by independent size-fractionation experiments. Our results demonstrate that the structural complexity of particles is critical to understand open-ocean backscattering and contribute to solving the enigma. Particulate optical backscattering is key to studying the oceanic carbon pump though it remains unclear what particles are detected. Here the authors show that complex particles larger than 1 µm help reproduce all the measured backscattering across the Atlantic Ocean and explain the majority of the signal.
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Affiliation(s)
- Emanuele Organelli
- Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH, Plymouth, UK. .,Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France.
| | - Giorgio Dall'Olmo
- Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH, Plymouth, UK.,National Centre for Earth Observation, Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH, Plymouth, UK
| | - Robert J W Brewin
- Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH, Plymouth, UK.,National Centre for Earth Observation, Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH, Plymouth, UK
| | - Glen A Tarran
- Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH, Plymouth, UK
| | - Emmanuel Boss
- School of Marine Sciences, University of Maine, Orono, 04469, ME, USA
| | - Annick Bricaud
- Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France
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4
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Advantages and Limitations to the Use of Optical Measurements to Study Sediment Properties. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8122692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Measurements of optical properties have been used for decades to study particle distributions in the ocean. They are useful for estimating suspended mass concentration as well as particle-related properties such as size, composition, packing (particle porosity or density), and settling velocity. Measurements of optical properties are, however, biased, as certain particles, because of their size, composition, shape, or packing, contribute to a specific property more than others. Here, we study this issue both theoretically and practically, and we examine different optical properties collected simultaneously in a bottom boundary layer to highlight the utility of such measurements. We show that the biases we are likely to encounter using different optical properties can aid our studies of suspended sediment. In particular, we investigate inferences of settling velocity from vertical profiles of optical measurements, finding that the effects of aggregation dynamics can seldom be ignored.
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Moutier W, Duforêt-Gaurier L, Thyssen M, Loisel H, Mériaux X, Courcot L, Dessailly D, Rêve AH, Grégori G, Alvain S, Barani A, Brutier L, Dugenne M. Evolution of the scattering properties of phytoplankton cells from flow cytometry measurements. PLoS One 2017; 12:e0181180. [PMID: 28708882 PMCID: PMC5510878 DOI: 10.1371/journal.pone.0181180] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/27/2017] [Indexed: 11/19/2022] Open
Abstract
After the exponential growth phase, variability in the scattering efficiency of phytoplankton cells over their complete life cycle is not well characterised. Bulk measurements are impacted by senescent cells and detritrus. Thus the analysis of the evolution of the optical properties thanks to their morphological and/or intra-cellular variations remains poorly studied. Using the Cytosense flow cytometer (CytoBuoy b.v., NL), the temporal course of the forward and sideward efficiencies of two phytoplankton species (Thalassiosira pseudonana and Chlamydomonas concordia) were analyzed during a complete life-cycle. These two species differ considerably from a morphological point of view. Over the whole experiment, the forward and sideward efficiencies of Thalassiosira pseudonana were, on average, respectively 2.2 and 1.6 times higher than the efficiencies of Chlamydomonas concordia. Large intra-species variability of the efficiencies were observed over the life cycle of the considered species. It highlights the importance of considering the optical properties of phytoplankton cells as a function of the population growth stage of the considered species. Furthermore, flow cytometry measurements were combined with radiative transfer simulations and biogeochemical and optical measurements. Results showed that the real refractive index of the chloroplast is a key parameter driving the sideward signal and that a simplistic two-layered model (cytoplasm-chloroplast) seems particularly appropriate to represent the phytoplankton cells.
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Affiliation(s)
- William Moutier
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
- * E-mail:
| | - Lucile Duforêt-Gaurier
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
| | - Mélilotus Thyssen
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, 13288 Marseille, France
| | - Hubert Loisel
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
| | - Xavier Mériaux
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
| | - Lucie Courcot
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
| | - David Dessailly
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
| | - Anne-Hélène Rêve
- Univ. Lille, UMR CNRS 8187 - LOG - Laboratoire d’Océanologie et de Géosciences, 62930 Wimereux, France
| | - Gérald Grégori
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, 13288 Marseille, France
| | - Séverine Alvain
- Centre National de la Recherche Scientifique, UMR CNRS 8187 - LOG - Laboratoire d’Océanologie et de Géosciences, 62930 Wimereux, France
| | - Aude Barani
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, 13288 Marseille, France
| | - Laurent Brutier
- Univ. Littoral Côte d’Opale, Univ. Lille, CNRS, UMR 8187, LOG, Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France
| | - Mathilde Dugenne
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, 13288 Marseille, France
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6
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Ramírez-Pérez M, Gonçalves-Araujo R, Wiegmann S, Torrecilla E, Bardaji R, Röttgers R, Bracher A, Piera J. Towards Cost-Effective Operational Monitoring Systems for Complex Waters: Analyzing Small-Scale Coastal Processes with Optical Transmissometry. PLoS One 2017; 12:e0170706. [PMID: 28107539 PMCID: PMC5249177 DOI: 10.1371/journal.pone.0170706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/09/2017] [Indexed: 11/30/2022] Open
Abstract
The detection and prediction of changes in coastal ecosystems require a better understanding of the complex physical, chemical and biological interactions, which involves that observations should be performed continuously. For this reason, there is an increasing demand for small, simple and cost-effective in situ sensors to analyze complex coastal waters at a broad range of scales. In this context, this study seeks to explore the potential of beam attenuation spectra, c(λ), measured in situ with an advanced-technology optical transmissometer, for assessing temporal and spatial patterns in the complex estuarine waters of Alfacs Bay (NW Mediterranean) as a test site. In particular, the information contained in the spectral beam attenuation coefficient was assessed and linked with different biogeochemical variables. The attenuation at λ = 710 nm was used as a proxy for particle concentration, TSM, whereas a novel parameter was adopted as an optical indicator for chlorophyll a (Chl-a) concentration, based on the local maximum of c(λ) observed at the long-wavelength side of the red band Chl-a absorption peak. In addition, since coloured dissolved organic matter (CDOM) has an important influence on the beam attenuation spectral shape and complementary measurements of particle size distribution were available, the beam attenuation spectral slope was used to analyze the CDOM content. Results were successfully compared with optical and biogeochemical variables from laboratory analysis of collocated water samples, and statistically significant correlations were found between the attenuation proxies and the biogeochemical variables TSM, Chl-a and CDOM. This outcome depicted the potential of high-frequency beam attenuation measurements as a simple, continuous and cost-effective approach for rapid detection of changes and patterns in biogeochemical properties in complex coastal environments.
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Affiliation(s)
- Marta Ramírez-Pérez
- Department of Physical and Technological Oceanography, Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
| | - Rafael Gonçalves-Araujo
- Phytooptics Group, Physical Oceanography of Polar Seas, Climate Sciences Division, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Sonja Wiegmann
- Phytooptics Group, Physical Oceanography of Polar Seas, Climate Sciences Division, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Elena Torrecilla
- Department of Physical and Technological Oceanography, Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
| | - Raul Bardaji
- Department of Physical and Technological Oceanography, Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
| | - Rüdiger Röttgers
- Remote Sensing Department, Institute for Coastal Research, Centre for Materials and Coastal Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
| | - Astrid Bracher
- Phytooptics Group, Physical Oceanography of Polar Seas, Climate Sciences Division, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.,Institute of Environmental Physics, University of Bremen, Bremen, Germany
| | - Jaume Piera
- Department of Physical and Technological Oceanography, Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
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7
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Remote Sensing of Particle Cross-Sectional Area in the Bohai Sea and Yellow Sea: Algorithm Development and Application Implications. REMOTE SENSING 2016. [DOI: 10.3390/rs8100841] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Cetinić I, Poulton N, Slade WH. Characterizing the phytoplankton soup: pump and plumbing effects on the particle assemblage in underway optical seawater systems. OPTICS EXPRESS 2016; 24:20703-20715. [PMID: 27607674 DOI: 10.1364/oe.24.020703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Many optical and biogeochemical data sets, crucial for algorithm development and satellite data validation, are collected using underway seawater systems over the course of research cruises. Phytoplankton and particle size distribution (PSD) in the ocean is a key measurement, required in oceanographic research and ocean optics. Using a data set collected in the North Atlantic, spanning different oceanic water types, we outline the differences observed in concurrent samples collected from two different flow-through systems: a permanently plumbed science seawater supply with an impeller pump, and an independent system with shorter, clean tubing runs and a diaphragm pump. We observed an average of 40% decrease in phytoplankton counts, and significant changes to the PSD in 10-45 µm range, when comparing impeller and diaphragm pump systems. Change in PSD seems to be more dependent on the type of the phytoplankton, than the size, with photosynthetic ciliates displaying the largest decreases in cell counts (78%). Comparison of chlorophyll concentrations across the two systems demonstrated lower sensitivity to sampling system type. Observed changes in several measured biogeochemical parameters (associated with phytoplankton size distribution) using the two sampling systems, should be used as a guide towards building best practices when it comes to the deployment of flow-through systems in the field for examining optics and biogeochemistry. Using optical models, we evaluated potential impact of the observed change in measured phytoplankton size spectra onto scattering measurements, resulting in significant differences between modeled optical properties across systems (~40%). Researchers should be aware of the methods used with previously collected data sets, and take into consideration the potentially significant and highly variable ecosystem-dependent biases in designing field studies in the future.
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9
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Davies EJ, McKee D, Bowers D, Graham GW, Nimmo-Smith WAM. Optically significant particle sizes in seawater. APPLIED OPTICS 2014; 53:1067-1074. [PMID: 24663303 DOI: 10.1364/ao.53.001067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/15/2014] [Indexed: 06/03/2023]
Abstract
Small particles (<10 μm) are often considered to play the dominant role in controlling scattering and absorption due to their relatively large numbers, which are typically found in the ocean. Here we present an approach for quantifying the size range of particles that contribute significantly to bulk inherent optical properties. We present a numerical assessment of the variability in optically significant particle sizes for simplistic populations that conform to the assumptions of homogeneous, spherical particles, and power-law size distributions. We use numerical predictions from Mie theory to suggest minimum and maximum particle sizes required for accurate predictions and observations of ocean optics for different particle size distributions (PSDs). When considering observed ranges of PSDs, our predictions suggest the need for measurements of optical properties and particles to capture information from particle sizes between diameters of 0.05-2000 μm in order to properly constrain relationships between particles and their associated optical properties. Natural particle populations in the ocean may present more complex PSDs that could be analyzed using the method presented here to establish optically significant size classes.
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10
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Smith BT, Davis RH. Sedimentation of algae flocculated using naturally-available, magnesium-based flocculants. ALGAL RES 2012. [DOI: 10.1016/j.algal.2011.12.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Peng F, Effler SW. Mass-specific scattering coefficient for natural minerogenic particle populations: particle size distribution effect and closure analyses. APPLIED OPTICS 2012; 51:2236-2249. [PMID: 22614397 DOI: 10.1364/ao.51.002236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/17/2012] [Indexed: 06/01/2023]
Abstract
The relationship between the particulate scattering coefficient (b(p)) and the concentration of suspended particulate matter (SPM), as represented by the mass-specific scattering coefficient of particulates (b(p)*=b(p)/SPM), depends on particle size distribution (PSD). This dependence is quantified for minerogenic particle populations in this paper through calculations of b(p)* for common minerals as idealized populations (monodispersed spheres); contemporaneous measurements of b(p), SPM, and light-scattering attributes of mineral particles with scanning electron microscopy interfaced with automated image and x-ray analyses (SAX), for a connected stream-reservoir system where minerogenic particles dominate b(p); and estimates of b(p) and its size dependency (through SAX results-driven Mie theory calculations), particle volume concentration, and b(p)*. Modest changes in minerogenic PSDs are shown to result in substantial variations in b(p)*. Good closure of the SAX-based estimates of b(p) and particle volume concentration with bulk measurements is demonstrated. Converging relationships between b(p)* and particle size, developed from three approaches, were well described by power law expressions.
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Affiliation(s)
- Feng Peng
- Upstate Freshwater Institute, Syracuse, New York 13214, USA.
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12
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Twardowski M, Zhang X, Vagle S, Sullivan J, Freeman S, Czerski H, You Y, Bi L, Kattawar G. The optical volume scattering function in a surf zone inverted to derive sediment and bubble particle subpopulations. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jc007347] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Stavn RH. Mass-specific scattering cross sections of suspended sediments and aggregates: theoretical limits and applications. OPTICS EXPRESS 2012; 20:201-219. [PMID: 22274344 DOI: 10.1364/oe.20.000201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The spectral mass-specific scattering cross section σ[PIM](λ) is most important for the remote sensing inversion of the concentration of suspended mineral matter in the coastal ocean. This optical parameter is also important in optical theory and therefore the theoretical limits of this parameter are important. There are differing reports in the literature on the magnitude of σ[PIM](λ) and its spectral slope in different coastal ocean systems. To account for and predict these differences, I have applied a model of the size distribution of primary suspended mineral particles and aggregates of these particles to theoretical calculations of σ[PIM](λ). I utilized a model of mineral particle aggregates by Khelifa and Hill [Khelifa, A. and P.S. Hill, J. Hydraul. Res. 44, 390 (2006)] and Latimer's optical model of aggregates [Latimer, P., Appl. Opt. 24, 3231, (1985)]. I have been able to account for the variations in magnitude and spectral slope of σ[PIM](λ). This analysis will apply to not only inverting the concentration of suspended mineral matter but also provides the basis for inverting the processes of coagulation and aggregation of primary mineral particles in determining sedimentation rates, budgets, etc.
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Affiliation(s)
- Robert H Stavn
- Department of Biology, P.O. Box 26174, University of North Carolina, Greensboro, NC 27402, USA.
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14
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Stemmann L, Boss E. Plankton and particle size and packaging: from determining optical properties to driving the biological pump. ANNUAL REVIEW OF MARINE SCIENCE 2012; 4:263-90. [PMID: 22457976 DOI: 10.1146/annurev-marine-120710-100853] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Understanding pelagic ecology and quantifying energy fluxes through the trophic web and from the surface to the deep ocean requires the ability to detect and identify all organisms and particles in situ and in a synoptic manner. An idealized sensor should observe both the very small living or dead particles such as picoplankton and detritus, respectively, and the large particles such as aggregates and meso- to macroplankton. Such an instrument would reveal an astonishing amount and diversity of living and nonliving particles present in a parcel of water. Unfortunately such sensors do not exist. However, complex interactions constrain the space, temporal, and size distributions of these objects in such ways that general rules can be inferred from the measurement of their optical properties. Recent technological developments allow for the in situ measurement of the optical properties and size distributions of particles and plankton in a way such that synoptic surveys are possible. This review deals with particle and plankton size distributions (PSDs) as well as how particles' geometry and nature affect their optical properties. Finally, we propose the integration of the PSD into size-structured mathematical models of biogeochemical fluxes.
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Affiliation(s)
- L Stemmann
- Université Pierre et Marie Curie (UPMC), Paris 06, UMR 7093, Observatoire Océanographique (LOV), F-06234 Villefranche/Mer, France.
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15
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Gallegos CL, Werdell PJ, McClain CR. Long‐term changes in light scattering in Chesapeake Bay inferred from Secchi depth, light attenuation, and remote sensing measurements. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jc007160] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - P. Jeremy Werdell
- Ocean Ecology Branch NASA Goddard Space Flight Center Greenbelt Maryland USA
| | - Charles R. McClain
- Ocean Ecology Branch NASA Goddard Space Flight Center Greenbelt Maryland USA
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Slade WH, Boss E, Russo C. Effects of particle aggregation and disaggregation on their inherent optical properties. OPTICS EXPRESS 2011; 19:7945-7959. [PMID: 21643044 DOI: 10.1364/oe.19.007945] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In many environments a large portion of particulate material is contained in aggregated particles; however, there is no validated framework to describe how aggregates in the ocean scatter light. Here we present the results of two experiments aiming to expose the role that aggregation plays in determining particle light scattering properties, especially in sediment-dominated coastal waters. First, in situ measurements of particle size distribution (PSD) and beam-attenuation were made with two laser particle sizing instruments (one equipped with a pump to subject the sample to aggregate-breaking shear), and measurements from the two treatments were compared. Second, clays were aggregated in the laboratory using salt, and observed over time by multiple instruments in order to examine the effects of aggregation and settling on spectral beam-attenuation and backscattering. Results indicate: (1) mass normalized attenuation and backscattering are only weakly sensitive to size changes due to aggregation in contrast to theory based on solid particles, (2) the spectral slope of beam-attenuation is indicative of changes in PSD but is complicated by instrument acceptance angle, and (3) the spectral shape of backscattering did not provide as clear a relationship with PSD as spectral beam attenuation, as is predicted by theory for solid spheres.
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Affiliation(s)
- Wayne H Slade
- School of Marine Sciences, University of Maine, Orono, ME 04469, USA.
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17
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Hill PS, Boss E, Newgard JP, Law BA, Milligan TG. Observations of the sensitivity of beam attenuation to particle size in a coastal bottom boundary layer. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006539] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Reynolds RA, Stramski D, Wright VM, Woźniak SB. Measurements and characterization of particle size distributions in coastal waters. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jc005930] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Agrawal YC, Mikkelsen OA. Shaped focal plane detectors for particle concentration and mean size observations. OPTICS EXPRESS 2009; 17:23066-23077. [PMID: 20052233 DOI: 10.1364/oe.17.023066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We describe a method of designing shaped focal plane detectors for achieving a range of objectives in measurement of particles suspended in a fluid. These detectors can be designed to measure the total concentration in a wide size range (e.g. 200:1) or concentration in a size sub-range (e.g. 63<d<500 microm), and Sauter mean or volume mean diameter. The derivation of these shaped focal plane detectors is rooted in small-angle forward light scattering. The detector shapes are completely general, requiring no assumptions on underlying particle size distribution. We show the theoretical development, numerical simulations and laboratory test results.
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Affiliation(s)
- Y C Agrawal
- Sequoia Scientific, Inc., 2700 Richards Road, Bellevue, WA 98005, USA.
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