Size matters: Effects of propagule size on dispersal in rivers
Data files
Jul 30, 2025 version files 69.04 KB
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Data-from-Farrow-et-al-SizeMatters.xlsx
57.79 KB
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README.md
11.25 KB
Abstract
Biological particles (e.g., bacteria, eggs, fruit/seeds, and larvae) of a wide range of sizes (i.e., 10-6 – 10-1 m) are transported over various distances (i.e., 100 - 104 m) downstream in rivers. We examined the effects of propagule size on downstream dispersal by releasing biodegradable microbeads (density ~ 1200 kg m-3) of three size classes (~150, 250, 350 µm) at the Speed River, Guelph, ON. Hitting distance estimates and longitudinal dispersion coefficients declined with particle size and were significantly different between 150 and 350 µm microbeads. The magnitude of these differences was relatively small (~ 5 m) because of the slow velocity (9.5 ± 0.01 cm s-1) and low turbulence (shear velocity = 1.9 ± 0.13 cm s-1) in the river. We examined the dispersion of larval and juvenile unionid mussels (size range = 56 – 415 µm, 247.54 ± 60.38 [mean ± SD] µm, N = 174) across a broader range of flow conditions by applying laminar and turbulent flow models in three river reaches of increasing velocity and turbulence. Model results indicated that the dispersal of smaller larvae increased disproportionately with increasing water column turbulence. Given that the peak in the size frequency distribution of larvae and juveniles corresponded to Rouse numbers (ratio of gravitational settling to water column turbulence) P < 1, we suggest a trade-off in propagule size in the taxon, whereby the increased dispersal of smaller juveniles may come at the cost of reduced settlement success in turbulent environments.
Dataset DOI: 10.5061/dryad.5tb2rbpgj
Description of the data and file structure
Particle release trials were undertaken at the Speed River reach on 29 September and 6, 13, and 24 October 2022. Alginate microbeads of three size classes (150, 250, and 350 µm) and types (calcium carbonate-, mica-, and riboflavin-loaded) were released into the stream and recaptured in drift nets (2.25 m length) positioned on the river bottom with their opening (0.45 m width × 0.30 m height) on the riverbed 2, 6, 10, 18, and 34-m downstream of the mid-stream release point.
Microbead capture data were used to calculate hitting distances and dispersion coefficients based on a 1D and 3D advection dispersion model. Parameters provided in the Data-from-Farrow-et-al-SizeMatters.xlsx file correspond to the raw microbead capture data, as well as the derived hitting distances and dispersion coefficients.
All data needed to calculate the derived parameters (e.g., microbead settling velocity, depth, shear velocity) following the procedures described in the original article are also included. Variables and units are provided in column headers and the metadata provided below. Missing data (NA) are indicated for trials that were removed because of failure to meet the criteria for analysis (See section 2.3 in the original article). All missing data represented as NA.
Worksheet/Tab 1: Farrow-et-al-SizeMatters-Data
Column name | Description | Units | Data format | Missing data code |
---|---|---|---|---|
Date | The date of the particle release trial, provided in the format (year-month-day). | - | Category | - |
Distance (m) | The distance downstream of the release point. | m | Number | - |
Count | The number of microbeads captured in the drift net. | - | Number | NA |
PercentCapture | The number of microbeads captured in the drift net, converted into a percentage of the total number released. | - | Number | NA |
Count per m^2 | The number of microbeads captured in the drift net, divided by the cross-sectional area of the drift net opening. | m^-2 | Number | NA |
Size (µm) | The size class of the captured microbeads. | µm | Number | - |
w_s (m/s) | The microbead settling velocity. | m/s | Number | - |
z_r (m) | The height above the riverbed that microbeads were released from. | m | Number | - |
Type | The type of microbead released. | - | Category | - |
Depth (m) | The depth of the river at the location. | m | Number | - |
TKE (m2/s2) | The turbulent kinetic energy measured at the location. | m2/s2 | Number | - |
u*est (m/s) | The shear velocity, estimated from the turbulent kinetic energy measured at the location. | m/s | Number | - |
U (m/s) | The velocity at the location. | m/s | Number | - |
24h-Q (m^3/s) | The 24-h discharge measured at determined at the Speed River monitoring station. | m^3/s | Number | - |
T (s) | The time estimated for microbeads to pass the drift net. | s | Number | - |
Microbead Flux (particles/m^2/s) | The microbead flux at a drift net. | particles/m^2/s | Number | NA |
Worksheet/Tab 2: Longitudinal dispersion_3D_for
Column name | Description | Units | Data format | Missing data code |
---|---|---|---|---|
River | The name of the river that microbeads were released in. | - | Category | - |
Date | The date of the particle release trial, provided in the format (year-month-day). | - | Category | - |
Size (µm) | The size class of the captured microbeads. | µm | Number | - |
Type | The type of microbead released. | - | Category | - |
Dx (m^2/s) | The longitudinal dispersion coefficient determined from the 3D advection dispersion model. | m^2/s | Number | - |
Worksheet/Tab 3: Longitudinal dispersion_1D_for
Column name | Description | Units | Data format | Missing data code |
---|---|---|---|---|
River | The name of the river that microbeads were released in. | - | Category | - |
Date | The date of the particle release trial, provided in the format (year-month-day). | - | Category | |
Size (µm) | The size class of the captured microbeads. | µm | Number | - |
Type | The type of microbead released. | - | Category | - |
Dx (m^2/s) | The longitudinal dispersion coefficient determined from the 1D advection dispersion model. | m^2/s | Number | - |
Worksheet/Tab 4: HittingDistancePreds-size corre
Column name | Description | Units | Data format | Missing data code |
---|---|---|---|---|
Type | The type of microbead. | - | Category | - |
Size (µm) | The average size of the microbead. | µm | Number | - |
Size/Sizemax | The ratio of microbead size to the largest microbead size. | - | Number | - |
Density (kg/m^3) | The calculated density of the microbead. | kg/m^3 | Number | - |
w_s corrected (m/s) | The size-corrected settling velocity. | m/s | Number | - |
Laminar model_hitting distance_corrected (m) | The predicted hitting distance based on the laminar model, corrected for microbead size. | m | Number | - |
Turbulent model_hitting distance_corrected (m) | The predicted hitting distance based on the turbulent model, corrected for microbead size. | m | Number | - |
Empirical_hitting distance (m) | The hitting distance derived from the empirical particle capture data. | m | Number | - |
SEx_empirical (m) | The standard error for the empirical hitting distance. | m | Number | - |
Resid_laminar (m) | The residual for the laminar model prediction. | m | Number | - |
Resid_turb (m) | The residual for the turbulent model prediction. | m | Number | - |
resid2_lam (m2) | The squared residual for the laminar model. | m^2 | Number | - |
resid2_turb (m2) | The squared residual for the turbulent model. | m^2 | Number | - |
RMSE_lam (m) | The root mean square error for the laminar model. | m | Number | - |
RMSE_turb (m) | The root mean square error for the turbulent model. | m | Number | - |