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Calcimator

Coral Growth Rate Calculator

Model coral colony linear extension rate based on species growth baseline, water temperature, light (PAR), and aragonite saturation state.

Inputs

Results

Effective growth rate (cm/yr)

0.85

Projected diameter (cm)13.51
Temperature factor0.95
Light factor0.6
Projected volume (cm³)646.1
Bleaching risk (%)0
Initial Volume Cm332.72
How to Use This Calculator
  1. Enter the coral colony extension rate in mm per year from annual density band counts.
  2. Input sea surface temperature (°C), salinity (ppt), and light intensity (mol photons/m²/day).
  3. Set the species to apply species-specific growth constants.
  4. Review the projected skeletal density and calcification rate in g/cm²/year.
  5. Compare current growth rates to historical baselines to quantify climate-driven declines.

How the result changes with Water temperature (°C)

Water temperature (°C)Effective growth rate (cm/yr)
130
210.12
300.55
370

What each input means

Species base growth (cm/yr)
Baseline linear extension rate for the species (e.g., 1-2 cm/yr for massive corals, 5-15 cm/yr for branching Acropora).
Water temperature (°C)
Mean annual water temperature. Optimal coral growth occurs at 25-29°C.
PAR (µmol/m²/s)
Photosynthetically active radiation reaching the coral. Higher light boosts zooxanthellae photosynthesis.
Aragonite saturation (Ω)
Seawater aragonite saturation state. Tropical surface waters typically 3.5-4.0; below 3.0 calcification slows.
Initial colony diameter (cm)
Current diameter of the coral colony.
Projection period (years)
Number of years to project coral growth.

What each result means

Effective growth rate (cm/yr)
Adjusted annual linear extension rate accounting for temperature, light, and calcification conditions.
Projected diameter (cm)
Estimated colony diameter after the projection period.
Temperature factor
Growth multiplier from temperature (1.0 = optimal, lower = suboptimal).
Light factor
Growth multiplier from PAR level (0-1 scale, saturating curve).
Projected volume (cm³)
Estimated colony volume assuming hemispherical growth form.
Bleaching risk (%)
Estimated bleaching probability if temperature exceeds 30°C.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Species base growth (cm/yr) = 1.5, Water temperature (°C) = 26, PAR (µmol/m²/s) = 300, Aragonite saturation (Ω) = 3.5 = 6 input(s) provided
  2. Calculate Effective growth rate
    Effective growth rate = baseGrowthRate * tempFactor * lightFactor * calcFactorClamped
    0.851 = 0.851
  3. Calculate Projected diameter
    Projected diameter = initialSizeCm + effectiveGrowthRate * yearsToProject
    13.51 = 13.51
  4. Calculate Temperature factor
    0.946 = 0.946

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