Analyze bottle tests, biomass shifts, and carbon uptake. See corrected rates, areal outputs, and summaries. Use structured inputs to study ecosystem energy transfer confidently.
Use one method at a time. The page layout stays stacked, while the input grid expands from one column to three columns by screen size.
| Method | Key Inputs | Example Output |
|---|---|---|
| Oxygen bottle | Initial 8.4, light 9.1, dark 7.8, 4 hours, 2 L, 0.05 m² | Daily gross ≈ 585 mg C/m²/day |
| Biomass change | 120 to 145 g dry mass/m², 10 days, carbon fraction 0.45 | Gross ≈ 2.53 g C/m²/day |
| Carbon uptake | 185 mg fixed carbon, 5 hours, 0.12 m², respiration 8 | Gross ≈ 466 mg C/m²/day |
Oxygen light and dark bottle: Net rate = (Light − Initial) ÷ Time. Respiration rate = (Initial − Dark) ÷ Time. Gross rate = (Light − Dark) ÷ Time. Carbon conversion uses O₂ × 12 ÷ (32 × PQ) for fixation and O₂ × 12 × RQ ÷ 32 for respiration.
Biomass accumulation: Observed biomass change = [(Final biomass × Carbon fraction) − (Initial biomass × Carbon fraction)] ÷ Days. Corrected NPP = Observed change + Herbivory loss + Litter loss. GPP = Corrected NPP + Autotroph respiration.
Carbon uptake: Base rate = Fixed carbon ÷ Time ÷ Area × Scaling factor. If the measurement is net, GPP = NPP + Respiration correction. If the measurement is gross, NPP = GPP − Respiration correction.
Primary productivity measures how quickly autotrophs convert inorganic carbon into organic matter. It helps describe ecosystem energy capture, carbon flow, and biological growth over time.
Gross productivity is total carbon fixed by photosynthesis. Net productivity is what remains after autotroph respiration is subtracted from that total.
Use the oxygen bottle method for aquatic samples when dissolved oxygen change is measured during light and dark incubations. It is common in limnology and plankton studies.
PQ and RQ help convert oxygen-based measurements into carbon-based estimates. They adjust for the stoichiometric link between oxygen exchange and carbon fixation or release.
A negative net community value means respiration exceeds gross carbon fixation over the scaled day. This can occur in shaded, nutrient-stressed, or heterotrophic systems.
Yes. Grazing, litter export, tissue loss, or unmeasured turnover can hide true production. That is why the biomass method includes optional correction terms.
Choose units that match your study design. Aquatic work often uses mg C/m²/day, while terrestrial work commonly uses g C/m²/day or annualized values.
No. It supports structured calculations, but site context, incubation design, nutrient status, light climate, and methodological bias still matter when interpreting productivity.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.