BIOL 230 Lecture Notes - Lecture 16: Primary Production, Unit
Document Summary
The majority of biomass in terrestrial areas of the earth is composed of plants not animals. Aquatic areas of the earth have much lower standing stocks of plants. Why do we care: green biomass stores carbon, reducing the greenhouse effect. Without this much green biomass we would all be roasted: amount of plant biomass strongly controlled by number of trophic levels, but we have lost the top trophic levels of many food webs. Ans: terrestrial plants less nutritious than aquatic plants, many land plants inedible. Terrestrial food webs are bottom heavy (green) and aquatic top heavy (blue). A: need to know rate of grass growth vs. mowing loss. Collect grass, dry it, weigh it to find carbon. Measure biomass at different time intervals and look at the difference. This suggests that herbivory rates differ because terrestrial plants have defense mechanisms. (toxic chemicals, spines). Primary production does not differ between terrestrial and aquatic systems, but herbivory rates do.
