Geometry, fractal dimension and settling velocity of flocs during flooding conditions in the Rhône ROFI

Many, Gaël; Madron, Xavier Durrieu de; Verney, Romaric; Bourrin, François; Renosh, Pannimpullath Remanan; Jourdin, Frédéric; Gangloff, Aurélien

doi:10.1016/j.ecss.2019.01.017

Cited by 28 publications

(22 citation statements)

References 57 publications

(75 reference statements)

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“…We apply statistical discrimination of marine snow into morphotypes and study the linkages between their composition in relation to the dynamics of plankton communities on the example of two comparable study areas within the Arctic marginal ice zones (the Baffin Bay and Fram Strait, Fig. 1 ) which are characterized by high productivity 20 , 31 , 32 and distinct phytoplankton bloom phases 19 , 33 , 34 . We hypothesized that our method could be used to investigate how the concentration of different categories of marine snow and their vertical distribution change during sequential phases of the phytoplankton bloom and how this could be linked to the carbon export.…”

Section: Introductionmentioning

confidence: 99%

Marine snow morphology illuminates the evolution of phytoplankton blooms and determines their subsequent vertical export

et al. 2021

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The organic carbon produced in the ocean’s surface by phytoplankton is either passed through the food web or exported to the ocean interior as marine snow. The rate and efficiency of such vertical export strongly depend on the size, structure and shape of individual particles, but apart from size, other morphological properties are still not quantitatively monitored. With the growing number of in situ imaging technologies, there is now a great possibility to analyze the morphology of individual marine snow. Thus, automated methods for their classification are urgently needed. Consequently, here we present a simple, objective categorization method of marine snow into a few ecologically meaningful functional morphotypes using field data from successive phases of the Arctic phytoplankton bloom. The proposed approach is a promising tool for future studies aiming to integrate the diversity, composition and morphology of marine snow into our understanding of the biological carbon pump.

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Section: Introductionmentioning

confidence: 99%

Marine snow morphology illuminates the evolution of phytoplankton blooms and determines their subsequent vertical export

et al. 2021

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“…"fines" or "fine sediment") and sand are different: sand particles are individual quasi-spherical grains (with typical density ρ s = 2, 650kg/m 3 for quartz particles), between 63 and 2, 000µm in diameter, d. Muddy sediments, especially clay particles (d < 2µm), have the ability to flocculate and often bond with organic matter. The resulting flocs vary widely in diameter (from 10 to 1, 000µm) and have relatively low densities (ρ f loc = O(1, 100 − 2, 000kg/m 3 )) with irregular shapes and lower settling velocities than sand [McCave, 1984;Eisma, 1993;Milligan and Hill , 1998;Hill et al, 2000;Fugate and Friedrichs, 2002;Khelifa and Hill , 2006;Manning et al, 2006;Dankers and Winterwerp, 2007;Chapalain et al, 2019;Many et al, 2019]. The spatial distribution of these different types of sediment is a function of morphology, supply, and hydrodynamic conditions.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the Composition of Sand and Mud Suspensions in Coastal and Estuarine Environments Using Combined Optical and Acoustic Measurements

et al. 2021

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Quantifying and characterizing suspended sediment is essential to successful monitoring and management of estuaries and coastal environments. To quantify suspended sediment, optical and acoustic backscatter instruments are often used. Optical backscatter systems are more sensitive to mud particles (< 63µm) and flocs, whereas acoustic Accepted ArticleThis article is protected by copyright. All rights reserved.Confidential manuscript submitted to JGR-Oceans allows us to estimate whether there are more sand or mud particles floating through the water. The relationship between "seeing" and "hearing" can be described in a single number, the sediment composition index (SCI). We successfully tested this approach in laboratory experiments and then applied it to a site on the coast of the Netherlands. This approach gives us a new way to understand environments that are both sandy and muddy.

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“…Thus, an iDAS design could be easily adapted to the LISST‐200X using the associated calibration chamber. However, there is no reason why the iDAS approach could not be applied to other particle imaging approaches, including laser sheet (Davies et al 2017; Markussen et al 2020) and holographic (Many et al 2019) approaches.…”

Section: Discussionmentioning

confidence: 99%

A method to measure marine particle aggregate disruption in situ

Ackleson

Rau

2020

Limnology & Ocean Methods

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Particle aggregation within aquatic environments is a primary factor controlling the vertical flux of suspended matter. The aggregation process is controlled by the rate of particle interaction, enhanced by turbulent motions and differential settling, and the probability that particles making contact will stick together. The larger the particle aggregate, the faster it will sink. We describe a new and novel method to measure the state of particle aggregation in situ as a function of turbulent energy using an inexpensive attachment, the in situ dis-aggregation system (iDAS), to a commercially available particle size instrument, a Sequoia Scientific LISST-100X. A small chamber is attached to the instrument tand sample is drawn into the chamber using an inexpensive, variable speed thruster designed for remotely operated underwater vehicles. Ambient water drawn into the sample chamber passes through a flexible tube of defined diameter and length. The flow velocity through the tube and tube dimensions are used to estimate the turbulent energy that particles experience. As turbulence increases, particle aggregations disrupt, shifting the size distribution towards smaller particles. The method was tested under controlled laboratory conditions using standard test clay material and within several coastal environments along the East Coast of the United States. In all instances, particle aggregations are shown to disrupt as turbulence increases, causing the particle size distribution to shift toward smaller fractured aggregates and component particles. The iDAS can be used to directly measure the aggregation state of suspended material and potentially to estimate the bonding strength between aggregated particles of different type.

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Geometry, fractal dimension and settling velocity of flocs during flooding conditions in the Rhône ROFI

Cited by 28 publications

References 57 publications

Marine snow morphology illuminates the evolution of phytoplankton blooms and determines their subsequent vertical export

Marine snow morphology illuminates the evolution of phytoplankton blooms and determines their subsequent vertical export

Characterizing the Composition of Sand and Mud Suspensions in Coastal and Estuarine Environments Using Combined Optical and Acoustic Measurements

A method to measure marine particle aggregate disruption in situ

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