Limnology Tools

Browse all available limnology tools.

Available tools

Alum Dosing Phosphorus Inactivation Calculate candidate stoichiometric reagent mass for supplied water/sediment labile phosphorus and calibrated Al:P ratio; not dosing advice, and alkalinity, pH, toxicity, reagent hydration and delivery constraints need specialist assessment.
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.
Anoxic Phosphorus Release Checker Screen actual sediment-interface low-oxygen and caller labile-P evidence jointly; candidates are not measured release, universal redox mechanism, inferred missing oxygen or remediation advice.
Area At Stage Hypsograph Calculator Qualified piecewise-linear calibration for Area At Stage Hypsograph Calculator. Actualincreasinglakelevel/area hypsographiccalibration,nonnegative independentlyqualifiedareas,not stage/storagevolumeor extrapolation. Increasingmatchedknots,noextrapolation,no universalcurve or fit. Examplesillustrative,actualsource independently verified;no safe-use approval or validated forecast.
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.
Areal Phosphorus Loading GM2 Calculator Normalize actual matched external-source phosphorus ledger to areal loading and explicit 365-day annualization; not loading-limit inversion or measured internal release.
Benthic Macroinvertebrate Biomass Area Calculator Pool actual blank-corrected benthic dry mass by summed sampled area, not mean of unequal-area densities; negative corrections retained, no habitat-wide extrapolation or taxonomic index.
Birgean Work Mixing Energy Calculator DiscreteidealBirgeanpotentialenergychangehomogeneousmixingusingactuallayerdepthcenters/volumes/massdensity,not turbulent energy efficiency or normalized lake stability. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Brunt Vaisala Frequency Thermocline Calculator ActualstablewaterfinitegradientBrunt–VäisäläN√(g/ρref×Δρ/Δz),positive-downwaterdensitynot atmosphericθgradient. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Cesium 137 Peak Year Marker Lookup Locate actual unique core Cs137 activity maximum and annotate explicit externally justified marker year; not universally assigning 1963/1986, hemispheric fallout timing or asserting unmixed sediment chronology.
Chloride Conservative Mass Balance Checker Audit conservative dissolved chloride inventory with trapezoidal sampled mass-flux integration and independent final inventory; this tracer is not chlorine disinfectant, and groundwater/deposition inputs must be included externally.
Chlorophyll A Extraction Concentration Convert blank-corrected multiwavelength extract absorbances with caller method coefficients and path/dilution/sample-volume correction; negative estimates are retained and solvent-specific calibration is external.
Chlorophyll Phosphorus Regression Prediction Fit a log-power chlorophyll/phosphorus relation to caller observations with within-range median prediction; no mutable published regression or uncorrected arithmetic-mean claim.
Chlorophyll Target Load Back Calculation Tool Compose inversion of a supplied chlorophyll/P power calibration with a steady Vollenweider-form loading model; excludes internal loads and does not guarantee a management outcome.
CO2 Flux Atmosphere Lake Combine a caller Henry equilibrium with measured dissolved CO2 and piston velocity into signed atmosphere–lake flux; positive is emission, negative uptake, and carbonate speciation is external.
Compensation Depth Light Level Invert constant optical extinction for a supplied compensation light threshold; a deeper-than-bottom model value is flagged, not silently clipped or declared biologically valid.
Conductivity Salinity Freshwater Approximation Converter Use explicit local freshwater conductivity/salinity calibration after caller linear temperature normalization; not universal seawater practical salinity, ionic composition inference or chemistry certification.
Density Current Plunge Depth Interpolate neutral-buoyancy depth for an inflow in a strictly stable measured density profile; unbracketed underflow/overflow remains censored, and entrainment, slope and momentum are not modeled.
Density Gradient Stratification Strength Compute signed N² from observed density gradients with depth positive down; negative values remain instability indicators rather than an invented real Brunt–Väisälä frequency.
Dilution Capacity Low Flow Invert ideal complete mixing for an effluent flow capacity when receiving concentration < target < effluent; not a legal discharge allowance, mixing-zone model or ecological guarantee.
Dissolved Oxygen Saturation Altitude Temp Calculator Approximate pure-freshwater oxygen saturation using bounded temperature cubic and dry-air station-pressure ratio; caller supplies actual pressure already altitude-resolved, not geodesy, exact standard solubility, salinity correction or observed deficit.
Effective Fetch Length Calculate the specified effective-fetch convention sum(F·cos²theta)/sum(cos theta) from measured radial fetches; no shoreline GIS or prevailing-wind inference.
Epilimnion Hypolimnion Volume Split Integrate a supplied piecewise-linear area-depth curve across thermal-layer boundaries including split contour intervals; geometry is supplied, not reconstructed from map coordinates.
Euphotic Zone Depth From Secchi Calculator Estimate euphotic depth from actual Secchi and explicit locally calibrated multiplier, retaining beyond-bottom model value; not Beer–Lambert threshold inversion or a universal biological light depth.
Evaporation Pan To Lake Coefficient Infer a pan-to-lake coefficient from a matched fixed-area observed lake water budget; negative inferred evaporation/coefficient exposes condensation or missing fluxes rather than being forced to an empirical default.
Evaporative Cooling Flux Lake Calculator Convert actual measured mass evaporation flux to signed latent heat flux; negative condensation retained, distinct from energy-budget inversion estimating evaporation.
Fall Turnover Density Inversion Trigger Screen resolved down-column density inversions against caller measurement tolerance; inversion is a mixing trigger screen, not proof of complete fall turnover.
Fetch Limited Wave Height Evaluate a supplied deep-water fetch-limited bulk wave-growth correlation; wind reference height, duration, shallow-water limits and calibration applicability are external.
Freezing Degree Days Ice Growth Calculator QualifiedcleariceStefanH²=H0²+C×FDD growthonly,independentC,no snow/whiteice/current/cracksor safeice travel prediction. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Freshwater Density From Temperature Evaluate the standard empirical pure-freshwater density approximation near atmospheric pressure for 0–40°C; excludes salinity, compression and dissolved-solids effects.
Gran Titration Alkalinity Fit the post-equivalence acid Gran function (Vs+Va)·10^(−pH) and extrapolate a nonnegative endpoint for monovalent acid alkalinity; activity corrections and endpoint validity require laboratory assessment.
Hardness Carbonate Noncarbonate Split Calculator Split actual hardness by matched alkalinity expressed as CaCO3 equivalents; no treating alkalinity as calcium concentration, individual ion speciation or titration analysis.
Heat Content Per Area Compute lake sensible heat relative to caller temperature from layer volumes and constant supplied density/heat capacity; reference changes alter absolute content, not heat differences.
Hypolimnetic Aeration Air Requirement Convert hypolimnetic oxygen demand to supplied-condition air volume/operating flow using air oxygen mass content and field transfer; unlike rated oxygen-transfer capacity, this sizes gas flow, not aeration equipment or mixing effects.
Hypolimnetic Oxygen Demand Rate Calculator Infer matched two-time hypolimnetic demand after independent net advected oxygen correction; distinct from OLS areal depletion fit, signed net replenishment retained and missing processes not uniquely diagnosed.
Hypsographic Curve Integration Integrate observed hypsographic area-depth contours into a cumulative volume curve with trapezoids; contour geometry is supplied and only the measured depth range is represented.
Ice Free Period Days Count Calculator ActualUTCcivil-date [iceout,nextfreeze)elapsedwhole days acrossyears/leapdates,not forecastfreezestability. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Ice Out Date Trend Slope Fit ice-out trend after fixed-reference circular phase unwrapping on a supplied standardized annual cycle; dates must be leap-normalized and anomalies must be interpretable within a half cycle.
Ice Thickness Stefan Law Integrate a Stefan conductive growth model with fixed snow thermal resistance and initial ice; excludes melting, flowing water, radiation and evolving snowpack.
Inflow Outflow Storage Residual Checker SignedstorageledgerresidualobservedΔS−(I−O),periodscopescomplete/external,no automaticallyinvent unmeasuredgroundwater. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Internal Load Release Areal Rate Infer signed internal phosphorus release as the residual of observed water inventory and external exchange, normalized by active sediment area/time; other missing processes can contribute to the residual.
Internal Rossby Radius Deformation Calculate two-layer internal Rossby radius c/|f| using supplied reduced gravity and signed Coriolis parameter; no latitude or coordinate transformation.
Internal Seiche Period Rectangular Estimate the fundamental rectangular nonrotating two-layer internal seiche period 2L/c; higher harmonics are excluded as duplicated scaling variants.
Inverse Stratification Under Ice Checker Screen actual under-ice 0–4°C warming-with-depth profile using caller measurement tolerance; candidate temperature evidence only, not salinity-aware stability or confirmation of whole-lake stratification.
Kelvin Wave Speed Thermocline Calculator Idealnonrotatinglonginternaltwo-layerKelvinwavespeed√(g′h1h2/(h1+h2)),rigidlid/sharpthermocline,not seicheperiod. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Lake Evaporation Energy Balance Method Estimate signed evaporation by a caller Bowen-ratio available-energy budget including storage/advected heat; negative results indicate condensation-model potential and missing fluxes are not diagnosed.
Lake Number Inertial Evaluate a Lake Number convention using Schmidt stability already in J/m² and water-side friction velocity; no extra gravity factor, wind-to-water conversion or universal mixing threshold.
Lead 210 Sediment Dating Evaluate unsupported Pb-210 constant-rate-of-supply inventory chronology and covariance-aware first-order age uncertainty; supply decay constant, supported-activity correction and complete inventory externally.
Light Attenuation Vertical Profile Propagate downwelling irradiance through layered Beer–Lambert extinction; supplied coefficients include only modeled optical attenuation and no bottom reflection.
Light Dark Bottle Productivity Balance initial/light/dark bottle oxygen to net, respiration and gross production with supplied carbon stoichiometry; incubation representativeness, gas leakage and bottle effects are not corrected.
Light Extinction Coefficient Secchi Calculator Estimate optical attenuation from paired measured Secchi depths using explicit calibrated dimensionless k·Z product; not assumed measured extinction, spectral turbidity decomposition or layered light propagation.
Littoral Zone Percent Area Classify measured lake-bottom patches by a caller colonization depth and sum area; assumes each representative depth describes its patch and does not infer vegetation presence or map geometry.
Load Reduction Required Percent Calculator Audit observed load-source ledger against caller total target and independently reducible fractions; not regulatory reduction mandate or guarantee of concentration/ecological response.
Load Target Concentration Gap Calculator Reconcile actual concentration/target gap to instantaneous well-mixed inventory difference, not converting concentration gap to annual load reduction without residence/retention evidence.
Mean Depth Calculator Audit matched volume/surface area for mean lake depth with independent maximum-depth consistency; not hypsographic integration or a shape-based inferred volume.
Metalimnion Thickness Locate one contiguous sampled metalimnion using a caller absolute-gradient threshold; disjoint layers are ambiguous and are not merged into a false single thickness.
Methane Bubbling Emission Estimate Normalize trap-measured bubble methane by dry-gas ideal-law correction and summed area×time; negative blank-corrected estimates are preserved as nondetection evidence, not clamped emissions.
Morphoedaphic Index MEI Calculator Compute explicit TDS/mean-depth morphoedaphic index convention; not conductivity-based MEI, fish-yield prediction or universal productivity calibration.
Net Surface Heat Flux Balance Calculator Reconcile separately measured surface fluxes and storage residual under downward-positive radiation/upward-positive turbulent convention; signed turbulent condensation retained, unmodeled advection may contribute residual.
Nitrogen Phosphorus Ratio Limitation Checker Convert matched mass N/P concentrations to molar ratio and screen caller bounds; ratios alone cannot diagnose nutrient limitation or bioavailability.
Oxygen Deficit Absolute Integrate oxygen deficit against supplied layer-specific saturation references and volumes; supersaturated layers contribute negative deficits, unlike a saturation-concentration model.
Oxygen Solubility Salinity Correction Calculator Qualified piecewise-linear calibration for Oxygen Solubility Salinity Correction Calculator. Actual fixedtemperature/pressure dissolvedoxygen salinity-correctionmeasuredfactorcalibration,nouniversal freshwaterfactor. Increasingmatchedknots,noextrapolation,no universalcurve or fit. Examplesillustrative,actualsource independently verified;no safe-use approval or validated forecast.
Phaeophytin Absorbance Correction Apply caller acid-correction convention Chl=k(Apre−Apost), phaeo=k(R·Apost−Apre); k must include method-specific acidification factors, and negative estimates are flagged rather than clamped.
Phosphorus Retention Coefficient Close matched phosphorus inflow/outflow/storage budget to apparent retention; negative retention or ratios above one expose unmodeled exchange and are not clamped.
Photic Zone Percent Depth Calculator Distinguish modeled photic-depth/maximum-depth ratio from physically capped depth fraction; not illuminated lake volume/area or an ecological euphotic-zone judgement.
Piston Velocity Gas Exchange Scale a measured reference gas-transfer piston velocity by a supplied Schmidt-number power relation; does not infer wind dependence or gas concentration gradients.
Plankton Settling Volume Liter Calculator Normalize actual blank-corrected plankton settled volume to original water sample; negative blank estimates retained as nondetection evidence, not biomass or counted-cell density.
Reaeration Coefficient Oxygen Transfer Calculator Integrate constant first-order reaeration toward caller saturation reference with exact exponential and signed supersaturated degassing; no respiration, variable volume, field transfer-efficiency or gas-supply sizing.
Relative Thermal Resistance Mixing Calculator Compute caller RTRM density contrast normalized to explicit reference contrast, retaining unstable sign; reference may reflect caller 4–5°C convention, not work/Schmidt stability or a universal mixing threshold.
Richardson Number Water Column Compute signed bulk Richardson number for a supplied shear-layer scale and density contrast; density inversion remains negative and no critical instability diagnosis is imposed.
Schmidt Stability Index Compute signed Schmidt potential-energy stability from piecewise-constant layer areas/densities and depth-positive-down centers; negative values indicate an inverted profile, not positive mixing energy.
Seasonal Heat Budget Change Calculator Reconcile seasonal sensible-heat change on matched fixed layer volumes with independent before/after temperatures; not absolute reference heat-content calculator, latent heat or volume-change correction.
Secchi Depth Transparency Recorder Record actual paired Secchi disappearance/reappearance with disagreement uncertainty, rejecting bottom-censored readings rather than calling them measured transparency.
Sedgwick Rafter Cell Density Calculator Estimate actual Sedgwick–Rafter counted-field density using measured field areas/chamber depth and dilution; no assumed full-cell volume, sampling variance or organism identification.
Sediment Accumulation Rate MM Year Calculator Compute observed dated-marker mean sediment thickness accumulation; not radionuclide age inversion, mass accumulation, compaction correction or an assumption of uniform deposition outside markers.
Sediment Focusing Factor Calculator Compare complete core inventory with explicit independently justified atmospheric reference to apparent sediment focusing; not corrected Pb210 chronology or proof deposition difference is solely focusing.
Shoreline Development Index Calculator Normalize actual same-resolution planar shoreline to equal-area circle; depends on shoreline resolution/islands and excludes GIS/geodesy measurement or ecological complexity guarantees.
Snow Load On Ice Bearing Checker Screen layered ice/snow hydrostatic freeboard for potential snow flooding; this is buoyancy only, not bearing strength or permission to walk, drive or work on ice.
Spring Turnover Trigger Temperature Checker Screen sampled near-isothermal ice-free water against explicit caller spring turnover temperature/spread tolerance; temperature similarity does not prove mixing, adequate wind or complete water-column coverage.
Stage Discharge Power Rating Evaluate a caller stage/discharge power rating with zero-flow control stage; stages at/below control are modeled dry, while backwater, hysteresis and calibration range remain external.
Stage Storage Volume Interpolation Interpolate storage for measured monotone stage/storage calibration within its observed bounds; no extrapolation, contour integration or invented lake geometry.
TDS From Conductivity Calculator Apply explicit caller local reference-temperature conductivity/TDS linear calibration including intercept; not direct gravimetric measurement or universal 0.5/0.7 factor.
Thermistor Chain Depth Interpolation Tool Interpolate each observed thermistor-chain profile to a shared depth grid only inside measured bounds; no time interpolation, sensor-gap reconstruction or profile extrapolation.
Thermocline Depth Max Gradient Identify a unique maximum absolute interval temperature gradient, reporting interval center rather than claiming sub-sample thermocline precision.
Trophic Category Classifier Map actual TSI to explicit caller upper-inclusive category scheme; no universal trophic labels, compound-index completeness or ecological endpoint diagnosis.
TSI Carlson Chlorophyll Calculator Apply Carlson chlorophyll TSI in µg/L with natural logarithm; pigment index does not uniquely classify all lake types.
TSI Carlson Secchi Calculator Apply Carlson Secchi TSI using observed meters; empirical clarity index may be confounded by nonalgal turbidity.
TSI Carlson Total Phosphorus Calculator Apply Carlson total-phosphorus TSI in µg/L; empirical nutrient index, not bioavailability, permit limit or ecological diagnosis.
TSI Composite Average Calculator Compute caller-requested diagnostic arithmetic of actual three Carlson indices with explicit weights, missing-evidence coverage and disagreement. NALMS cautions that averaging these indices is inappropriate for estimating algal biomass; prefer chlorophyll and examine index deviations. This is not a recommended ecological classifier or lake-state certification.
Vollenweider Phosphorus Load Limit Invert a caller Vollenweider-form steady retention relation for target areal external phosphorus load; not an authoritative load limit or site-specific ecological guarantee.
Volume From Bathymetric Contours Calculator Actualcontourarea-depthtrapezoidvolumecompletebottomcoverage,not stageinterpolationonly/mesh exactintegration. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Water Balance Precipitation Evaporation Calculator ActualdirectlakeP−Ewatervolumecontributiononly,not allcatchmentinflows/seepageor complete balance. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Watershed Lake Area Drainage Ratio Calculator Actualexternaldelineatedtributarywatershed/lakearea drainageratio,sameunits/not infernutrientload or delineategeodesy. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Wedderburn Number Evaluate W=g′h²/(u*²L) from caller two-layer density contrast, upper thickness, friction velocity and fetch; no universal upwelling or turnover criterion.
White Ice Black Ice Layer Split Calculator Observedtwo-layerwhite/blackicethicknessfractions,not inferbearingcapacityor safeice travel. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Wind Stress Mixing Depth Estimate Screen mixing depth by supplied useful wind work against the rho·N²·h³/12 energy of uniform linear stratification; wind-work velocity/efficiency require calibration, not universal turbulent mixing.
Zooplankton Length Weight Regression Calculator Fit caller matched zooplankton dry-mass/length log-power relation and within-range conditional median prediction; coefficients/taxon/units external, no arithmetic mean without log-residual correction or universal biomass equation.

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