Ecosystem Ecology Ecosystem • One-way flow of energy through the trophic levels • A cycling of materials from abiotic to biotic and back Biotic Energy Heat/Motion Abiotic Primary Production Community Net PP Total Area World NPP (g/m^2) (mill. Km^2) (bill. tons/yr) • Initial capture of Desert 90 18 1.6 energy into the Temperate 1240 12 14.8 ecosystem Forest Trop.Rain 2200 17 37.8 • Photosynthesis Forest • Two types of PP Lakes/ 250 2 0.5 Streams – Gross Open 125 332 41.5 – Net Ocean Reefs/ 2500 0.6 1.6 Algal Beds What limits primary production in Bottom-up Model ecosystems? Increased Productivity: • increased trophic levels supported • Marine: light and nutrients • higher biomass at all • Freshwater: light, nutrients, trophic levels pollution • Terrestrial: light, water 1 Secondary Production • Energy flow •Rate • Ecological efficiency Three hundred trout are needed to support one person for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971) 2 Where does this energy/biomass go? Energy pyramid For example: CATERPILLAR Digest/Absorb: 1/2 of what they eat. Of this: • 2/3 absorbed goes to cellular respiration (CO2,H2O, heat) • 1/3 absorbed is added BIOMASS at that level Energy pyramid Energy lost 3 Biogeochemical cycles • Water, nitrogen, carbon, phosphorous, etc… • Involve geological (atmosphere, lithosphere, hydrosphere) and biological (trophic levels) components Carbon Water cycle Nitrogen cycle 4 Direct values • Private goods or commodity values • Harvested – Meat – Fuelwood/timber – Edible/medicinal plants • Consumptive and productive use Indirect values Example: River vegetation • Public goods, nonconsumptive use value • Benefits from biodiversity not involving harvesting or destroying – Ecosystem productivity – Water quality – Soil protection – Climate – Flood control – Waste treatment and nutrient retention Ecosystem productivity Soil and water resources • Primary productivity- • Buffering ecosystems energy –Flood • Terrestrial and – Drought aquatic – Water quality • Diversity-productivity • Logging, farming, development affect soil relationship erosion – Useless for farming – Kill aquatic life – Water undrinkable – Loss of electrical output 5 Climate regulation Waste treatment/nutrient retention • Local: shade, water • Aquatic communities transpiration, (fungi and bacteria) windbreaks • Break down/immobilize pollutants (2.4 trill) • Regional: • Store sewage and deforestation -> lower nutrient runoff for rainfall, lower uptake photosynthetic organisms of CO2 (global & nitrogen fixing warming) • New York Bight Species relationships Recreation and ecotourism • Predation (bottom-up • Enjoyment! and top-down) • Hiking, fishing, camping, rock climbing, • Pollination bird watching • Microorganisms • Ecotourism- to experience unusual communities Option value Existence value • Future potential to provide an economic • Value attached to preventing extinction of benefit to human society species, habitat destruction, genetic • Genetic improvement to crops- disease degredation resistance, harvest increase… • Use of flagship species (charismatic • Biological control megafauna) • Medicinal 6.