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Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Terrestrial nutrient cycling / Nutrient recycling versus new inputs across ecosystem age

Nutrient recycling versus new inputs across ecosystem age

Young ecosystems live on nutrients supplied by weathering and deposition, whereas old, weathered ecosystems run mostly on tight recycling of nutrients through plants, litter and microbes, with phosphorus gradually occluded.

Boundary: where this process starts

Starts with: Young ecosystems draw nutrients from weathering and deposition

Boundary: where it ends

Ends after: Leaching and runoff export the surplus; Sorption and occlusion remove phosphorus from the cycle as the soil ages

PARTICIPANTSRESOURCESPlantsMicrobesIron oxidesParent rockAtmosphereOtherparticipantsPhosphorusNitrogenWaterMineralnutrientsPlant litterImpact +4 of 5. Click for details and evidence.70% ↻ reinforces · strong · 0.6 plant uptakeImpact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +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.20% leachingImpact -3 of 5. Click for details and evidence.10% sorptionImpact 02 of 5. Click for details and evidence.Impact 02 of 5. Click for details and evidence.Young ecosystems draw nutrients from weathering and deposition: uses up Phosphorususes upYoung ecosystems draw nutrients from weathering and deposition: uses up Mineral nutrientsuses upPlants take up nutrients and resorb part of them before leaf fall: uses up Phosphorususes upPlants take up nutrients and resorb part of them before leaf fall: uses up Nitrogenuses upLitter returns nutrients to the surface soil where fine roots concentrate: makes PhosphorusmakesLitter returns nutrients to the surface soil where fine roots concentrate: makes NitrogenmakesLitter returns nutrients to the surface soil where fine roots concentrate: uses up Plant litteruses upFate of nutrients released by decomposition: uses PhosphorusFate of nutrients released by decomposition: uses NitrogenFate of nutrients released by decomposition: uses WaterLeaching and runoff export the surplus: uses up Phosphorususes upLeaching and runoff export the surplus: uses up Nitrogenuses upLeaching and runoff export the surplus: uses Waterdrawn from weatheringPhosphorus: drawn from weatheringsupplied by weatheringand depositionMineral nutrients: supplied by weathering and depositionresorbed before leaffallPhosphorus: resorbed before leaf falltaken up and partlyresorbedNitrogen: taken up and partly resorbedconcentrated in surfacesoilPhosphorus: concentrated in surface soilconcentrated near finerootsNitrogen: concentrated near fine rootsreturns nutrients tosurface soilPlant litter: returns nutrients to surface soilcycled back into plantsPhosphorus: cycled back into plantsreleased and taken upNitrogen: released and taken upcarries dissolvednutrientsWater: carries dissolved nutrientsexported as surplusPhosphorus: exported as surplusexported as surplusNitrogen: exported as surpluscarries surplusnutrients awayWater: carries surplus nutrients awayStart: Nutrientrecycling versus newinputs across ecosyst…STARTStart: Nutrient recycling versus new inputs across ecosystem ageEnd: Nutrient recyclingversus new inputsacross ecosystem ageENDEnd: Nutrient recycling versus new inputs across ecosystem ageYoung ecosystems drawnutrients fromweathering a…👍1📄1Young ecosystems draw nutrients from weathering and depositionPlants take upnutrients and resorbpart of them befo…📄1Plants take up nutrients and resorb part of them before leaf fallLitter returnsnutrients to thesurface soil where fi…📄1Litter returns nutrients to the surface soil where fine roots concentrateFate of nutrientsreleased bydecomposition📄1Fate of nutrients released by decompositionLeaching and runoffexport the surplus📄1 ↗1Leaching and runoff export the surplusSorption and occlusionremove phosphorus fromthe cycle as the so…📄1 ↗1Sorption and occlusion remove phosphorus from the cycle as the soil ages
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.

Young ecosystems draw nutrients from weathering and deposition
Parent rockAtmospherePhosphorusMineral nutrients
Evidence (1) · added by Loopa
  • Walker & Syers 1976, The fate of phosphorus during pedogenesis, Geoderma, doi:10.1016/0016-7061(76)90066-5: Primary apatite P dominates total P in young soils. (confidence 0.8)
Plants take up nutrients and resorb part of them before leaf fall
PlantsNitrogenPhosphorus
Evidence (1) · added by Loopa
  • Vitousek 1982, Nutrient cycling and nutrient use efficiency, American Naturalist, doi:10.1086/283931: Resorption raises nutrient use efficiency and is a plant strategy on poor soils. (confidence 0.8)
Litter returns nutrients to the surface soil where fine roots concentrate
PlantsPlant rootsPlant litterNitrogenPhosphorus
Evidence (1) · added by Loopa
  • Jackson 1996, A global analysis of root distributions for terrestrial biomes, Oecologia, doi:10.1007/bf00333714: Most fine roots lie in the upper soil layers in every biome, which positions them to intercept nutrients released from litter. (confidence 0.8)
⑂ Fate of nutrients released by decomposition
PlantsSoil waterIron oxidesNitrogenPhosphorusWater
Evidence (1) · added by Loopa
  • Vitousek & Sanford 1986, Nutrient cycling in moist tropical forest, Annual Review of Ecology and Systematics, doi:10.1146/annurev.es.17.110186.001033: Moist tropical forests on infertile soils cycle nutrients tightly with small losses. Shares are illustrative estimates for an old, infertile soil (range 55-85 / 5-30 / 5-20 percent). (confidence 0.4)
Leaching and runoff export the surplus
Drainage waterRiversNitrogenPhosphorusWater
Evidence (1) · added by Loopa
  • Vitousek & Sanford 1986, Nutrient cycling in moist tropical forest, Annual Review of Ecology and Systematics, doi:10.1146/annurev.es.17.110186.001033: Losses are small in tight systems and rise with nutrient richness. (confidence 0.8)
Sorption and occlusion remove phosphorus from the cycle as the soil ages
Iron oxidesAluminum oxidesPhosphateIron oxides
Evidence (1) · added by Loopa
  • Walker & Syers 1976, The fate of phosphorus during pedogenesis, Geoderma, doi:10.1016/0016-7061(76)90066-5: Occluded P rises as soil ages, shifting ecosystems to P limitation. (confidence 0.8)