Biology 2483A Lecture Notes - Lecture 21: Primary Production, Herbivore, Nitrogen Cycle
14 Jan 2019
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Bio 2483 lecture 21 nutrient supply and cycling. Elemental composition of organisms (as % of dry mass) Energy comes in through sunlight, captured by plants and gets transferred through trophic system. Once nutrients obtained, can be cycled in the system. Plants and microorganisms take up nutrients in simple, soluble forms from the environment. take it through roots: animals mostly get nutrients in food as large, complex molecules. The water contains dissolved organic matter, minerals, and gases (the soil solution). The smallest are clays (< 2 m): atmospheric inputs (fixation, deposition, the atmosphere is the ultimate source of carbon (co2 by autotrophs) & nitrogen for ecosystems. Some n-fixing bacteria are free-living; others are symbionts symbionts: interact with plants in a way to form symbiotic relationship. Legumes forming nitrogen-fixing nodules fix n inside nodules nodules are where the bacteria interact with the plant look at nodules to see how rich they are in fixing nitrogen: many bac inside these nodules.
