FOR305H1 Lecture 7: Lecture 7 - Ecosystem Ecology&Biogeochemistry
Document Summary
Only 16 nutrients really limiting to plants. Question: how can more than 16 species coexist if they can only specialize on one limiting nutrient: neutral theory. But really, even fewer nutrients actually limit plants: primary macronutrients are the main ones that actually limit ecosystem productivity. If add both have interaction: this is on good soil, similar dynamics to agriculture trends. If add nitrogen to old soils, there is no response: but if add phosphorus alone there is a response now, also if add nitrogen and phosphorus, it"s no better than adding just phosphorus. Answer: there isn"t nitrogen in lava, generally true in parent material, nitrogen comes from atmosphere: N is an inert gas (not very reactive) Lightening creates reactive nitrogen that can be deposited from atmosphere, but happens at low rates. Biological process: bacteria that can extract nitrogen from atmosphere. Do this in symbiosis with plants: in lava: At 300 years, there"s a bit from fixation.