scholarly journals On predicting particle capture rates in aquatic ecosystems

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261400
Author(s):  
Alexis Espinosa-Gayosso ◽  
Marco Ghisalberti ◽  
Jeff Shimeta ◽  
Gregory N. Ivey
Keyword(s):  
Particle Size ◽  
Parameter Space ◽  
Aquatic Ecosystems ◽  
Larval Settlement ◽  
Suspended Particles ◽  
Relevant Parameter ◽  
Particle Capture ◽  
Diverse Range ◽  
Functional Relationships ◽  
Contact Rates

Recent advances in understanding the capture of moving suspended particles in aquatic ecosystems have opened up new possibilities for predicting rates of suspension feeding, larval settlement, seagrass pollination and sediment removal. Drawing on results from both highly-resolved computational fluid dynamics (CFD) simulations and existing experimental data, we quantify the controlling influence of flow velocity, particle size and collector size on rates of contact between suspended particles and biological collectors over the parameter space characterising a diverse range of aquatic ecosystems. As distinct from assumptions in previous modeling studies, the functional relationships describing capture are highly variable. Contact rates can vary in opposing directions in response to changes in collector size, an organism’s size, the size of particles being intercepted (related to diet in the case of suspension feeders), and the flow strength. Contact rates shift from decreasing to increasing with collector diameter when particles become relatively large and there is vortex shedding in the collector wake. And in some ranges of the ecologically relevant parameter space, contact rates do not increase strongly with velocity or particle size. The understanding of these complex dependencies allows us to reformulate some hypotheses of selection pressure on the physiology and ecology of aquatic organisms. We discuss the benefits and limitations of CFD tools in predicting rates of particle capture in aquatic ecosystems. Finally, across the complete parameter space relevant to real aquatic ecosystems, all quantitative estimates of particle capture from our model are provided here.

Particle capture and low-Reynolds-number flow around a circular cylinder

2012 ◽  
Vol 710 ◽  
pp. 362-378 ◽  
Author(s):  
Alexis Espinosa-Gayosso ◽  
Marco Ghisalberti ◽  
Gregory N. Ivey ◽  
Nicole L. Jones
Keyword(s):  
Particle Size ◽  
Reynolds Number ◽  
Larval Settlement ◽  
Capture Rate ◽  
Reynolds Numbers ◽  
Particle Capture ◽  
Particle Size Range ◽  
Reynolds Number Flow ◽  
Number Flow ◽  
First Time

AbstractParticle capture, whereby suspended particles contact and adhere to a solid surface (a ‘collector’), is an important mechanism in a range of environmental processes. In aquatic systems, typically characterized by low collector Reynolds numbers ($\mathit{Re}$), the rate of particle capture determines the efficiencies of a range of processes such as seagrass pollination, suspension feeding by corals and larval settlement. In this paper, we use direct numerical simulation (DNS) of a two-dimensional laminar flow to accurately quantify the rate of capture of low-inertia particles by a cylindrical collector for $\mathit{Re}\leq 47$ (i.e. a range where there is no vortex shedding). We investigate the dependence of both the capture rate and maximum capture angle on both the collector Reynolds number and the ratio of particle size to collector size. The inner asymptotic expansion of Skinner (Q. J. Mech. Appl. Maths, vol. 28, 1975, pp. 333–340) for flow around a cylinder is extended and shown to provide an excellent framework for the prediction of particle capture and flow close to the leading face of a cylinder up to $\mathit{Re}= 10$. Our results fill a gap between theory and experiment by providing, for the first time, predictive capability for particle capture by aquatic collectors in a wide (and relevant) Reynolds number and particle size range.

scholarly journals A Numerical Study of the Effect of Particle Size on Particle Deposition on Turbine Vanes and Blades

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110178
Author(s):  
Zhengang Liu ◽  
Weinan Diao ◽  
Zhenxia Liu ◽  
Fei Zhang
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Numerical Study ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Particle Capture ◽  
Factors Affecting ◽  
Pressure Surface ◽  
Deposition Area ◽  
Turbine Vanes

Particle deposition could decrease the aerodynamic performance and cooling efficiency of turbine vanes and blades. The particle motion in the flow and its temperature are two important factors affecting its deposition. The size of the particle influences both its motion and temperature. In this study, the motion of particles with the sizes from 1 to 20 μm in the first stage of a turbine are firstly numerically simulated with the steady method, then the particle deposition on the vanes and blades are numerically simulated with the unsteady method based on the critical viscosity model. It is discovered that the particle deposition on vanes mainly formed near the leading and trailing edge on the pressure surface, and the deposition area expands slowly to the whole pressure surface with the particle size increasing. For the particle deposition on blades, the deposition area moves from the entire pressure surface toward the tip with the particle size increasing due to the effect of rotation. For vanes, the particle capture efficiency increases with the particle size increasing since Stokes number and temperature of the particle both increase with its size. For blades, the particle capture efficiency increases firstly and then decreases with the particle size increasing.

scholarly journals Effects of CO<sub>2</sub> on particle size distribution and phytoplankton abundance during a mesocosm bloom experiment (PeECE II)

2008 ◽  
Vol 5 (2) ◽  
pp. 509-521 ◽  
Author(s):  
A. Engel ◽  
K. G. Schulz ◽  
U. Riebesell ◽  
R. Bellerby ◽  
B. Delille ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Large Scale ◽  
Phytoplankton Community ◽  
Co2 Enrichment ◽  
Suspended Particles ◽  
Phytoplankton Abundance ◽  
General Importance ◽  
Co2 Treatment

Abstract. The influence of seawater carbon dioxide (CO2) concentration on the size distribution of suspended particles (2–60 μm) and on phytoplankton abundance was investigated during a mesocosm experiment at the large scale facility (LFS) in Bergen, Norway, in the frame of the Pelagic Ecosystem CO2 Enrichment study (PeECE II). In nine outdoor enclosures the partial pressure of CO2 in seawater was modified by an aeration system to simulate past (~190 μatm CO2), present (~370 μatm CO2) and future (~700 μatm CO2) CO2 conditions in triplicates. Due to the initial addition of inorganic nutrients, phytoplankton blooms developed in all mesocosms and were monitored over a period of 19 days. Seawater samples were collected daily for analysing the abundance of suspended particles and phytoplankton with the Coulter Counter and with Flow Cytometry, respectively. During the bloom period, the abundance of small particles (<4 μm) significantly increased at past, and decreased at future CO2 levels. At that time, a direct relationship between the total-surface-to-total-volume ratio of suspended particles and DIC concentration was determined for all mesocosms. Significant changes with respect to the CO2 treatment were also observed in the phytoplankton community structure. While some populations such as diatoms seemed to be insensitive to the CO2 treatment, others like Micromonas spp. increased with CO2, or showed maximum abundance at present day CO2 (i.e. Emiliania huxleyi). The strongest response to CO2 was observed in the abundance of small autotrophic nano-plankton that strongly increased during the bloom in the past CO2 mesocosms. Together, changes in particle size distribution and phytoplankton community indicate a complex interplay between the ability of the cells to physiologically respond to changes in CO2 and size selection. Size of cells is of general importance for a variety of processes in marine systems such as diffusion-limited uptake of substrates, resource allocation, predator-prey interaction, and gravitational settling. The observed changes in particle size distribution are therefore discussed with respect to biogeochemical cycling and ecosystem functioning.

Size-Based Structure and Production in the Pelagia of Lakes Ontario and Michigan

1994 ◽  
Vol 51 (11) ◽  
pp. 2603-2611 ◽  
Author(s):  
W. Gary Sprules ◽  
Andy P. Goyke
Keyword(s):  
Particle Size ◽  
Analytical Solutions ◽  
Secondary Production ◽  
Aquatic Ecosystems ◽  
Lake Ontario ◽  
Quadratic Trend ◽  
Periodic Oscillations ◽  
Predator Prey ◽  
Pelagic Food Webs ◽  
Biomass Spectra

Analytical solutions to allometric models of predator–prey interactions in aquatic ecosystems indicate that normalized biomass spectra should consist of a smooth quadratic trend around which periodic oscillations occur. We confirm these assertions by showing that parabolas provide good models of normalized biomass as a function of body mass within homogeneous trophic groupings of organisms (phytoplankton, zooplankton, or fish) in the pelagic food webs of Lakes Ontario and Michigan. In addition, we show that the normalized biomass spectrum for the whole pelagic community in these lakes can be modelled by a series of parabolas of constant curvature that are aligned along a smooth quadratic base, as predicted by theory. Total secondary production in Lake Ontario is predicted from these models to be 234 kcal∙m−2∙yr−1 (1 kcal = 4.19 kJ), which compares favourably with sampling estimates of about 154 kcal∙m−2∙yr−1 for the whole community except rotifers and some hypolimnetic organisms, but both are higher than particle-size conversion efficiency estimates of 75–125 kcal∙m−2∙yr−1.

scholarly journals Effects of Water Particles in the Jinjiang River Estuary on the Physiological and Biochemical Characteristics of Microcystit Flos-Aquae

2021 ◽  
Author(s):  
Yiting Nan ◽  
Peiyong Guo ◽  
Hui Xing ◽  
Sijia Chen ◽  
Bo Hu ◽  
...  
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Protein Content ◽  
Suspended Particulate Matter ◽  
Soluble Protein ◽  
Suspended Particles ◽  
Dose Effect ◽  
Soluble Protein Content ◽  
Sod Activity ◽  
Suspended Particulate

Abstract The effects of different concentrations (100,150,200,250 mg/L) and different particle sizes (0–75µm, 75–120µm, 120–150µm, 150–500µm) on soluble protein content, SOD and CAT activity, MDA content, chlorophyll a content and photosynthetic parameters of Microcystis flos-aquae were studied, the mechanism of the effect of suspended particulate matter on the physiology and biochemistry of Microcystis flos-aquae was discussed. The results showed that the soluble protein content of Microcystis flos-aquae did not change obviously after being stressed by suspended particles of different concentration/diameter. The SOD activity of Microcystis flos-aquae increased at first and then decreased with the increase of the concentration of suspended particulate matter. The SOD activity of Microcystis flos-aquae reached 28.03 U/mL when the concentration of suspended particulate matter was 100 mg/L. The CAT activity of Microcystis flos-aquae increased with the increase of the concentration of suspended particles, and reached the maximum value of 12.45 U/mgprot in the concentration group of 250 mg/L, showing a certain dose-effect. The effect of small particle size on SOD, CAT and MDA of Microcystis flos-aquae was more significant than that of large particle size. The larger the concentration and the smaller the particle size, the stronger the attenuation of light and the lower the content of chlorophyll a. Both Fv/Fm and Fv/F0 of Microcystis flos-aquae increased at first and then decreased under different concentration/size of suspended particles. The relative electron transfer rate gradually returned to the normal level with the passage of time. There was no significant difference in α value between treatment group and control group, ETRmax and Ik decreased.

scholarly journals Crab Diets Differ Between Adjacent Estuaries and Habitats Within a Sheltered Marine Embayment

2021 ◽  
Vol 8 ◽  
Author(s):  
Theo I. Campbell ◽  
James R. Tweedley ◽  
Danielle J. Johnston ◽  
Neil R. Loneragan
Keyword(s):  
Aquatic Ecosystems ◽  
Prey Availability ◽  
Dietary Composition ◽  
Recreational Fisheries ◽  
Seasonal Differences ◽  
Diverse Range ◽  
Bivalve Shell ◽  
Marine Embayment ◽  
Macroinvertebrate Fauna ◽  
High Calorie

Portunid crabs contribute to significant commercial and recreational fisheries globally and are commonly fished in estuaries and/or marine embayments, which are amongst the most degraded of all aquatic ecosystems. Portunus armatus were collected seasonally between April and February from five locations across three systems in temperate south-western Australia. The dietary composition of crabs was quantified and compared between two estuaries (Peel-Harvey and Swan-Canning) and a sheltered marine embayment (Cockburn Sound) containing three distinct habitats: shallow seagrass, shallow sand and deep sand. Overall, crabs ingested large volumes of bivalves (both live organisms and dead shell), polychaetes, crustaceans (e.g., amphipods, small decapods), and smaller volumes of teleosts, echinoderms and plant material (seagrass, algae). Analysis of Similarities showed that dietary composition varied significantly among the five locations (two estuaries and three habitats within Cockburn Sound) and seasons, with greater location than seasonal differences in the two estuaries. Diets were most distinct in the Cockburn Sound seagrass due to greater volumes of decapods and teleosts and smaller volumes of bivalve shell consumed in this habitat. Crabs from both estuaries consumed greater quantities of bivalves than those from Cockburn Sound. Seasonal differences in both estuaries were greatest between summer and winter, with a more diverse range of prey and large quantities of bivalves ingested in summer, whereas small bivalves and bivalve shell in the Peel-Harvey and polychaetes and other crustaceans in the Swan-Canning, were consumed in greater quantities in winter. The summer diet in the Peel-Harvey Estuary in the current study was compared to that 20 years previous and with documented change in the benthic macroinvertebrate fauna. Currently, crabs consume smaller volumes of high-calorie prey, i.e., polychaetes, small bivalves and teleosts, and instead ingest greater proportions of calcareous material than previously. This marked shift in dietary composition parallels changes in benthic macroinvertebrates in the Peel-Harvey Estuary. Overall, prey availability appears to be the major factor influencing the spatial and temporal differences in P. armatus diets in these three coastal systems.

scholarly journals Efficient approximations for stationary single-channel Ca2+ nanodomains across length scales

2020 ◽  
Author(s):  
Y Chen ◽  
C Muratov ◽  
V Matveev
Keyword(s):  
Parameter Space ◽  
Single Channel ◽  
Asymptotic Series ◽  
Rational Functions ◽  
Great Accuracy ◽  
Model Parameters ◽  
Relevant Parameter ◽  
Buffer Concentration ◽  
Computationally Efficient ◽  
Wide Range

ABSTRACTWe consider the stationary solution for the Ca2+ concentration near a point Ca2+ source describing a single-channel Ca2+ nanodomain, in the presence of a single mobile Ca2+ buffer with one-to-one Ca2+ binding. We present computationally efficient approximants that estimate stationary single-channel Ca2+ nanodomains with great accuracy in broad regions of parameter space. The presented approximants have a functional form that combines rational and exponential functions, which is similar to that of the well-known Excess Buffer Approximation and the linear approximation, but with parameters estimated using two novel (to our knowledge) methods. One of the methods involves interpolation between the short-range Taylor series of the buffer concentration and its long-range asymptotic series in inverse powers of distance from the channel. Although this method has already been used to find Padé (rational-function) approximants to single-channel Ca2+ and buffer concentration, extending this method to interpolants combining exponential and rational functions improves accuracy in a significant fraction of the relevant parameter space. A second method is based on the variational approach, and involves a global minimization of an appropriate functional with respect to parameters of the chosen approximations. Extensive parameter sensitivity analysis is presented, comparing these two methods with previously developed approximants. Apart from increased accuracy, the strength of these approximants is that they can be extended to more realistic buffers with multiple binding sites characterized by cooperative Ca2+ binding, such as calmodulin and calretinin.STATEMENT OF SIGNIFICANCEMathematical and computational modeling plays an important role in the study of local Ca2+ signals underlying vesicle exocysosis, muscle contraction and other fundamental physiological processes. Closed-form approximations describing steady-state distribution of Ca2+ in the vicinity of an open Ca2+ channel have proved particularly useful for the qualitative modeling of local Ca2+ signals. We present simple and efficient approximants for the Ca2+ concentration in the presence of a mobile Ca2+ buffer, which achieve great accuracy over a wide range of model parameters. Such approximations provide an efficient method for estimating Ca2+ and buffer concentrations without resorting to numerical simulations, and allow to study the qualitative dependence of nanodomain Ca2+ distribution on the buffer’s Ca2+ binding properties and its diffusivity.

Characteristic study of ionic species in nano, ultrafine, fine and coarse particle size mode at a traffic sampling site

2006 ◽  
Vol 22 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Guor-Cheng Fang ◽  
Yuh-Shen Wu ◽  
Shih-Yo Chang ◽  
Jui-Yeh Rau ◽  
Shih-Han Huang ◽  
...  
Keyword(s):  
Particle Size ◽  
Sampling Site ◽  
Principal Component ◽  
Ionic Species ◽  
Suspended Particles ◽  
Winter Period ◽  
Average Mass ◽  
Mass Size ◽  
Pollutant Source ◽  
Central Taiwan

A micro-orifice uniform deposit impactor (MOUDI) and a nano-MOUDI were used to measure the atmospheric coarse (PM2.5-10), fine (PM2.5), ultrafine (PM0.056 - 1) and nano (< 0.056 μm) particle concentrations at a traffic sampling site in central Taiwan during the winter period from November 2004 to January 2005. Meanwhile, concentrations of major ionic species (Cl-, NO3−, SO42−, NH4+, Na+, K+, Ca2+ and Mg2+) were also extracted from various particle size modes (nano, ultrafine, fine and coarse) and analysed by ion chromatography (DIONEX-100). The mass size distribution of ambient suspended particles exhibited two modes. The size ranges of the particles at these two particle size modes were between 1.0 and 1.8 mm and 3.2 and 5.6 mm, respectively. The average mass media aerodynamic diameter (MMAD) of suspended particles was 0.99 mm in this study. In addition, statistical methods, such as correlation coefficient and principal component analysis, were also used to identify the possible pollutant source for various particles size modes (nano, ultrafine, fine and coarse) during the winter months at a traffic sampling site in central Taiwan

Observations of the Particle Size Distribution and Concentration in a Coastal System using an In Situ Laser Analyzer

2002 ◽  
Vol 36 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Teresa Serra ◽  
Xavier Casamitjana ◽  
Jordi Colomer ◽  
Timothy C. Granata
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Water Column ◽  
Size Distribution ◽  
Posidonia Oceanica ◽  
High Energy ◽  
Suspended Particles ◽  
Energy Conditions ◽  
Coastal System

An in situ laser particle size analyzer (LISST-100, Sequoia Scientific, Inc.) has been used to study the particle size distribution and concentration of biological and non biological particles in the water column of a Mediterranean coastal system. Two field campaigns have been carried out during low and high energy conditions of the flow, caused by the passage of a storm front. For the low energy period, the water column remained stratified, whereas for the high energetic period the water column was warmer and well mixed. The first study dealt with the distribution of particles near the bottom of the coastal area. Here, two regions were taken into account. The first region was a sea-grass meadow of Posidonia oceanica and the second region was a barren sand area. The second study dealt with the determination of the vertical distribution of suspended particles in the whole water column of the system. The results showed a decrease in the vertical concentration of suspended particles in the water column with the passage of the storm front, which was associated with advection of warm water mass rather than by vertical mixing. In contrast, vertical resuspension determined the fate of suspended particles at the bottom of the water column and an increase of their concentration was found.

Deuterium retention in Be-D co-deposits formed over an ITER relevant parameter space

2020 ◽  
Vol T171 ◽  
pp. 014014 ◽  
Author(s):  
M J Baldwin ◽  
M J Simmonds ◽  
G De Temmerman ◽  
R P Doerner
Keyword(s):  
Parameter Space ◽  
Relevant Parameter ◽  
Deuterium Retention
Sign in / Sign up

Export Citation Format

Share Document