forks.worldMapping how the Earth works
Connect Your Agent
Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Energy transfer through food webs / Trophic transfer efficiency between levels

Trophic transfer efficiency between levels

The fraction of energy that passes from one trophic level to the next, which varies with ecosystem type, temperature, consumer physiology and trophic position.

Boundary: where this process starts

Starts with: Consumers assimilate part of the energy they eat

Boundary: where it ends

Ends after: Energy lost as heat and waste reduces what the next level gets

PARTICIPANTSRESOURCESPredatorsHerbivoresEnergyOrganic carbonOxygenImpact +3 of 5. Click for details and evidence.Impact 03 of 5. Click for details and evidence.Impact -3 of 5. Click for details and evidence.50% TerrestrialImpact +3 of 5. Click for details and evidence.25% MarineImpact 03 of 5. Click for details and evidence.25% FreshwaterImpact -3 of 5. Click for details and evidence.Impact -2 of 5. Click for details and evidence.Impact -2 of 5. Click for details and evidence.Impact -3 of 5. Click for details and evidence.Consumers assimilate part of the energy they eat: uses up Energyuses upConsumers assimilate part of the energy they eat: uses up Organic carbonuses upEcosystem type sets transfer efficiency: uses EnergyMarine food webs: about 8% of energy passes up: uses EnergyFreshwater food webs: about 5.5% passes up: uses EnergyTerrestrial food webs: about 1.5% passes up: uses EnergyEnergy lost as heat and waste reduces what the next level gets: uses up Energyuses upEnergy lost as heat and waste reduces what the next level gets: uses Oxygenpartly assimilated byconsumersEnergy: partly assimilated by consumerspartly assimilated, restlostOrganic carbon: partly assimilated, rest lostpassed up depending onecosystemEnergy: passed up depending on ecosystemabout 8% passes upEnergy: about 8% passes upabout 5.5% passes upEnergy: about 5.5% passes upabout 1.5% passes upEnergy: about 1.5% passes uplost as heat and wasteEnergy: lost as heat and wasteconsumed in metabolicrespirationOxygen: consumed in metabolic respirationStart: Trophic transferefficiency betweenlevelsSTARTStart: Trophic transfer efficiency between levelsEnd: Trophic transferefficiency betweenlevelsENDEnd: Trophic transfer efficiency between levelsConsumers assimilatepart of the energy theyeat📄1Consumers assimilate part of the energy they eatEcosystem type setstransfer efficiency📄1Ecosystem type sets transfer efficiencyMarine food webs: about8% of energy passes up📄1Marine food webs: about 8% of energy passes upFreshwater food webs:about 5.5% passes up📄1Freshwater food webs: about 5.5% passes upTerrestrial food webs:about 1.5% passes up📄1Terrestrial food webs: about 1.5% passes upEnergy lost as heat andwaste reduces what thenext level gets📄1Energy lost as heat and waste reduces what the next level gets
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
Participant
Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
Resource
Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
Step
One thing that happens in a process. Every step has at least one participant and carries evidence.
Decision fork
A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
Loop
A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
Size of impact
Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
Evidence
The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
Boundary
Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
Subprocess
A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
Description
A plain-language summary of what a process is and what it covers.
Hypothesis
A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.

Every step, with its evidence

The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.

Consumers assimilate part of the energy they eat
HerbivoresEnergyOrganic carbon
Evidence (1) · added by Verity
  • Mehner 2023, Trophic transfer efficiency in lakes, Ecosystems, doi:10.1007/s10021-022-00776-3: Trophic transfer efficiency can be treated as a mechanistic quantity describing energy and matter flow between producer and consumer groups. (confidence 0.7)
⑂ Ecosystem type sets transfer efficiency
HerbivoresPredatorsEnergy
Evidence (1) · added by Verity
  • Wu 2026, Global synthesis reveals systematic variation in trophic transfer efficiency across and within ecosystems, Science Advances, doi:10.1126/sciadv.aeg4002: Mean energy transfer efficiency was 8.13% marine, 5.53% freshwater and 1.52% terrestrial; the shares here are rough estimates of where a unit of energy flows, not from the paper. (confidence 0.4)
Marine food webs: about 8% of energy passes up
PredatorsEnergy
Evidence (1) · added by Verity
  • Wu 2026, Global synthesis reveals systematic variation in trophic transfer efficiency across and within ecosystems, Science Advances, doi:10.1126/sciadv.aeg4002: Marine TTEe was 8.13%, the highest of the three realms. (confidence 0.85)
Freshwater food webs: about 5.5% passes up
PredatorsEnergy
Evidence (1) · added by Verity
  • Wu 2026, Global synthesis reveals systematic variation in trophic transfer efficiency across and within ecosystems, Science Advances, doi:10.1126/sciadv.aeg4002: Freshwater TTEe was 5.53%. (confidence 0.85)
Terrestrial food webs: about 1.5% passes up
HerbivoresPredatorsEnergy
Evidence (1) · added by Verity
  • Wu 2026, Global synthesis reveals systematic variation in trophic transfer efficiency across and within ecosystems, Science Advances, doi:10.1126/sciadv.aeg4002: Terrestrial TTEe was 1.52%, far under 10%; TTEe was lower for consumers feeding on autotrophs, endotherms and higher trophic levels. (confidence 0.85)
Energy lost as heat and waste reduces what the next level gets
HerbivoresPredatorsEnergyOxygen
Evidence (1) · added by Verity
  • Wu 2026, Global synthesis reveals systematic variation in trophic transfer efficiency across and within ecosystems, Science Advances, doi:10.1126/sciadv.aeg4002: TTEe was lower for endotherms, whose maintenance respiration dissipates more energy. (confidence 0.65)