Areal Hypolimnetic Oxygen Depletion

Fit net hypolimnetic oxygen-inventory depletion and normalize by area; negative depletion records replenishment, and changing hypolimnetic boundaries or advective supply require separate correction.

Description

Hypolimnetic oxygen depletion describes a change in total deep-water oxygen inventory over time.

Hypolimnetic oxygen depletion describes a change in total deep-water oxygen inventory over time. Fitting inventory rather than concentration avoids treating a changing concentration alone as a mass loss.^[1]

The tool returns netInventoryDepletionKgPerDay, arealDepletionGramsPerM2Day, fitRSquared. The computation uses supplied observations and parameters rather than acquiring measurements.

When to use Areal Hypolimnetic Oxygen Depletion

Use this for the following task: Fit net hypolimnetic oxygen-inventory depletion and normalize by area; negative depletion records replenishment, and changing hypolimnetic boundaries or advective supply require separate correction. Prepare observations and calibration parameters on the same unit and reporting basis.

How to use Areal Hypolimnetic Oxygen Depletion and understand its results

Prepare the measured quantities and supplied model parameters. Match the units and align paired lists before calculating.
Enter timesDays, hypolimneticOxygenInventoriesKg, hypolimneticAreaM2 according to the field table, then run the tool.
Read netInventoryDepletionKgPerDay, arealDepletionGramsPerM2Day, fitRSquared. Use the calculation below to interpret the selected mean or the model’s signs, units and comparison flags.
Review the supplied assumptions and calibration before comparing or reporting the result.

Input field	Meaning	Value type and bounds	Requirement
timesDays	Times days	list of number	Required
hypolimneticOxygenInventoriesKg	Hypolimnetic oxygen inventories kg	list of number	Required
hypolimneticAreaM2	Hypolimnetic area m2	number	Required

Supply increasing times, aligned nonnegative oxygen inventories and positive hypolimnetic area. Fit a straight line and return signed depletion, normalized rate and R².

net depletion=−leastSquaresSlope(inventory versus days); areal g/(m²·day)=1000×depletion/area

The symbols and boundary conditions refer to the supplied fields and the implementation described above.

Output field	Meaning	Value type
netInventoryDepletionKgPerDay	Net inventory depletion kg per day	number
arealDepletionGramsPerM2Day	Areal depletion grams per m2 day	number
fitRSquared	Fit r squared	number

json

{
  "input": {
    "timesDays": [
      0,
      1,
      2
    ],
    "hypolimneticOxygenInventoriesKg": [
      100,
      90,
      80
    ],
    "hypolimneticAreaM2": 1000
  },
  "output": {
    "netInventoryDepletionKgPerDay": 10,
    "arealDepletionGramsPerM2Day": 10,
    "fitRSquared": 1
  }
}

Limitations and assumptions

Negative depletion represents replenishment. Changing deep-water boundaries and advective supply require separate correction; this does not isolate sediment oxygen demand.

Numerical inputs must be finite. Input-shape and calculation checks do not establish measurement quality or the validity of a supplied calibration.

Alternative or Complementary methods

Choose Oxygen Deficit Absolute when you need its operation: Integrate oxygen deficit against supplied layer-specific saturation references and volumes; supersaturated layers contribute negative deficits, unlike a saturation-concentration model. Choose Anoxia Risk Checker for the complementary operation: Screen finite time to a caller oxygen comparison under positive constant net depletion; negative projected balance is an unmet-demand model deficit, not physical negative oxygen or a diagnosis of anoxia.

Background reference: Least squares estimation.

References

Least squares estimation — NIST/SEMATECH

Similar or alternative tools

Oxygen Deficit Absolute
Integrate oxygen deficit against supplied layer-specific saturation references and volumes; supersaturated layers contribute negative deficits, unlike a saturation-concentration model.
Anoxia Risk Checker
Screen finite time to a caller oxygen comparison under positive constant net depletion; negative projected balance is an unmet-demand model deficit, not physical negative oxygen or a diagnosis of anoxia.