BIO 262 Lecture Notes - Lecture 6: Parent Material, Photic Zone, Eutrophication
28 Apr 2019
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Document Summary
Nutrients, atoms, ions, molecules needed by organisms. Continuously cycled between nonliving environment (air, rocks, soil, water) & organisms. Driven directly/indirectly by solar energy and gravity. Must be replaced by recycling (not continuously lost like energy) Productivity of ecosystems limited by recycling of nutrients. Production limited by regeneration of nutrients from soil. Some nutrients are added to soil through weathering of parent material. Only 10% of required nutrients supplied by weathering. At equilibrium, net losses must = replenishment from weathering. Weathering insufficient to supply plants with essential elements (ca, mg, k, na, n, p, s, etc. ) at the rates required. Falls 90% short of supplying needed nutrients rest from detritus. Most of nutrients in ecosystems supplied from regeneration of nutrients from detritus (organic material) Detritus is essential for ecosystem function (nutrients from biological sources rather than weathering) More than 90% of plant biomass enters detritus pool and excreta, etc. recycled to ecosystem. Breakdown of leaf litter is a complex process.
