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Calcimator

Plankton Biomass Calculator

Calculate plankton cell density and carbon biomass from net tow or water sample counts using standard oceanographic methods.

Inputs

Results

Cell density (cells/L)

1,250

Cell density (cells/mL)1.25
Total cells in sample125,000
Carbon biomass (µg C/L)0.07
Carbon biomass (mg C/m³)0.07
Est. Chl-a (µg/L)0
How to Use This Calculator
  1. Enter the net tow volume filtered in cubic meters from the flowmeter reading.
  2. Input the wet weight of the plankton sample in milligrams.
  3. Set the size fraction analyzed (e.g., >200 µm for mesozooplankton).
  4. Review the biomass concentration in mg/m³ and standardized to mg dry weight/m³.
  5. Compare to seasonal baseline values to assess ecosystem productivity trends.

How the result changes with Subsample volume (mL)

Subsample volume (mL)Cell density (cells/L)
10125
3536
6519
9014

What each input means

Cells counted in subsample
Number of plankton cells counted under the microscope in the subsample aliquot.
Subsample volume (mL)
Volume of the subsample aliquot examined (e.g., Sedgwick-Rafter cell = 1 mL).
Total sample volume (mL)
Total volume of the concentrated sample after net tow or filtration.
Water volume filtered (L)
Volume of seawater that passed through the plankton net or filter.
Avg cell volume (µm³)
Average biovolume per cell in cubic micrometers. Small diatoms ~100-500, large diatoms ~1000-50000.
C conversion (pg C/µm³)
Carbon-to-biovolume conversion factor. Typical: 0.11 pg C/µm³ for diatoms, 0.22 for dinoflagellates.

What each result means

Cell density (cells/L)
Estimated plankton cell concentration per liter of seawater.
Cell density (cells/mL)
Estimated plankton cell concentration per milliliter.
Total cells in sample
Extrapolated total cell count in the concentrated sample.
Carbon biomass (µg C/L)
Estimated phytoplankton carbon biomass per liter.
Carbon biomass (mg C/m³)
Equivalent biomass in mg carbon per cubic meter (same value as µg C/L).
Est. Chl-a (µg/L)
Rough chlorophyll-a estimate assuming C:Chl ratio of 50:1.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Cells counted in subsample = 250, Subsample volume (mL) = 1, Total sample volume (mL) = 500, Water volume filtered (L) = 100 = 6 input(s) provided
  2. Calculate Cell density
    Cell density = totalCellsInSample / waterFilteredL
    1250 = 1250
  3. Calculate Cell density
    Cell density = cellsPerLiter / 1000
    1.25 = 1.25
  4. Calculate Total cells in sample
    Total cells in sample = cellsCounted * concentrationFactor
    125000 = 125000

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