Values and units of parameters used in the model
| Symbol . | Value . | Unit . | Description . | ||
|---|---|---|---|---|---|
| Key (primary) parameters | |||||
| V | 1.12 | mm3 | Body volume (haemolymph and tissue compartments) | ||
| h0 | 2.5 | mm | Height of the cylindrical model | ||
| AM | 0.4 | mm2 | Flow cross-sectional area of the medium flow | ||
| Δx | 0.02 | mm | Thickness of the carapace lacuna | ||
| Φ | 0.4 | Tissue fraction of body volume | |||
| ζ | 0.25 | Fraction of total tissue in the central tissue cylinder | |||
| a0 | 0.0058 | nmol s-1 mm-3 | Volume-specific O2 consumption rate (whole body) | ||
| V̇M | 0.8333 | mm3 s-1 | Medium flow rate | ||
| Q̇H | 0.0311 | mm3 s-1 | Perfusion rate | ||
| αM | 0.0137 | nmol mm-3 kPa-1 | Solubility coefficient for O2 in water | ||
| αH | 0.0123 | nmol mm-3 kPa-1 | Solubility coefficient for O2 in haemolymph | ||
| αT | 0.0147 | nmol mm-3 kPa-1 | Solubility coefficient for O2 in tissue | ||
| DM | 0.0020 | mm2 s-1 | Diffusion coefficient for O2 in water | ||
| DH | 0.0015 | mm2 s-1 | Diffusion coefficient for O2 in haemolymph | ||
| DT | 0.0010 | mm2 s-1 | Diffusion coefficient for O2 in tissue | ||
| g | 0.0010 | nmol s-1 mm-2 kPa-1 | Permeability of the cuticular diffusion barrier | ||
| Δr | 0.005 | mm | Radial distance between two grid points | ||
| Δh | 0.1 | mm | Axial distance between two grid points | ||
| Δt | ≤0.005 | s | Time interval for numerical calculation | ||
| Derived (secondary) parameters | |||||
| 0.120 | mm | Radius of the central tissue cylinder | |||
| 0.280 | mm | Outer radius of the truncal haemolymph space | |||
| 0.350 | mm | Outer radius of the peripheral tissue layer | |||
| 0.500 | mm | Outer radius of the medium lacuna | |||
| r0 | 0.520 | mm | Outer radius of the carapace lacuna | ||
| a | 0.015 | nmol s-1 mm-3 | Volume-specific O2 consumption rate (pure tissue) | ||
| νM | 2.09 | mm s-1 | Flow velocity of the medium in the medium lacuna | ||
| νHC | 0.13 | mm s-1 | Flow velocity of the haemolymph in the carapace lacuna | ||
| νHT | 0.96 | mm s-1 | Flow velocity of the haemolymph in the trunk lacuna | ||
| Symbol . | Value . | Unit . | Description . | ||
|---|---|---|---|---|---|
| Key (primary) parameters | |||||
| V | 1.12 | mm3 | Body volume (haemolymph and tissue compartments) | ||
| h0 | 2.5 | mm | Height of the cylindrical model | ||
| AM | 0.4 | mm2 | Flow cross-sectional area of the medium flow | ||
| Δx | 0.02 | mm | Thickness of the carapace lacuna | ||
| Φ | 0.4 | Tissue fraction of body volume | |||
| ζ | 0.25 | Fraction of total tissue in the central tissue cylinder | |||
| a0 | 0.0058 | nmol s-1 mm-3 | Volume-specific O2 consumption rate (whole body) | ||
| V̇M | 0.8333 | mm3 s-1 | Medium flow rate | ||
| Q̇H | 0.0311 | mm3 s-1 | Perfusion rate | ||
| αM | 0.0137 | nmol mm-3 kPa-1 | Solubility coefficient for O2 in water | ||
| αH | 0.0123 | nmol mm-3 kPa-1 | Solubility coefficient for O2 in haemolymph | ||
| αT | 0.0147 | nmol mm-3 kPa-1 | Solubility coefficient for O2 in tissue | ||
| DM | 0.0020 | mm2 s-1 | Diffusion coefficient for O2 in water | ||
| DH | 0.0015 | mm2 s-1 | Diffusion coefficient for O2 in haemolymph | ||
| DT | 0.0010 | mm2 s-1 | Diffusion coefficient for O2 in tissue | ||
| g | 0.0010 | nmol s-1 mm-2 kPa-1 | Permeability of the cuticular diffusion barrier | ||
| Δr | 0.005 | mm | Radial distance between two grid points | ||
| Δh | 0.1 | mm | Axial distance between two grid points | ||
| Δt | ≤0.005 | s | Time interval for numerical calculation | ||
| Derived (secondary) parameters | |||||
| 0.120 | mm | Radius of the central tissue cylinder | |||
| 0.280 | mm | Outer radius of the truncal haemolymph space | |||
| 0.350 | mm | Outer radius of the peripheral tissue layer | |||
| 0.500 | mm | Outer radius of the medium lacuna | |||
| r0 | 0.520 | mm | Outer radius of the carapace lacuna | ||
| a | 0.015 | nmol s-1 mm-3 | Volume-specific O2 consumption rate (pure tissue) | ||
| νM | 2.09 | mm s-1 | Flow velocity of the medium in the medium lacuna | ||
| νHC | 0.13 | mm s-1 | Flow velocity of the haemolymph in the carapace lacuna | ||
| νHT | 0.96 | mm s-1 | Flow velocity of the haemolymph in the trunk lacuna | ||
Data refer to a 2.5 mm-long, fasting D. magna without embryos in the brood chamber at food-free, normoxic conditions and to 20°C.