🔋 GPP = NPP + Respiration — plants use roughly half of the energy they capture in photosynthesis (GPP) for their own cellular respiration. Only what remains (NPP) becomes new biomass available to consumers.
🌿 NPP is the energy base for all other life — every herbivore, predator, and decomposer ultimately depends on the net production of plants. NPP sets the upper limit on ecosystem biomass and biodiversity.
🌎 Climate drives NPP across biomes — warm, wet biomes (tropical forests, estuaries) produce the most NPP. Deserts and tundra produce the least. Temperature, precipitation, and sunlight are the key controls.
🧮 The respiration fraction matters — plants in harsh environments (cold, dry) spend a higher percentage of GPP on respiration, leaving less NPP. This is why identical GPP can yield very different NPP across biomes.