Transcript Ecosystems
Ecosystems A division of the biome through which energy flows and materials cycle Biogeochemical Cycles The pattern of movement of the elements through living organisms Dependent upon the characteristics of the element and the need of the organism for the element SPONCH elements Sulfur Phosphorous Oxygen Nitrogen Carbon Hydrogen Carbon Carbon is taken in as CO2 in the gaseous form or As Bicarbonate ion in water( HCO3-1) Atmospheric CO2 has increased in the past 100 years due to the burning of fossil fuels Greenhouse gases are CH4 – methane and CO( carbon monoxide) as well as CO2 Levels of Carbon Dioxide Carbon Dioxide levels Oceans and CO2 levels The CO2 in the ocean is related to the amount of photosynthesis in the plankton in the surface waters of the ocean Carbonates are stored in the shells of the ocean CO2 is dispersed throughout the ocean by a conveyer like belt that distributes water from the top to the bottom Carbon Levels Photoautotrophs Organism that convert light energy to chemical energy and utilize CO2 to build the basic molecules of life( molecular skeletons) The organisms are classified as producers Cyanobacteria Primary consumers Small larvae and invertebrates eat the plankton and algaes and pass the energy along These are organoheterotrophs Zooplankton Secondary Consumers Eat primary consumers . Energy transferred from one organism to another Secondary Consumers Higher level consumers Predatory fish eyes Swordfishes, which hunt in water as cold as 3°C (about 37°F), can maintain their brain and eye temperatures 10°C15°C (18°F 27°F) above ambient temperatures by using a specially adapted heating organ in muscle next to their eyes. The biological significance of this has been a mystery. Now, however, innovative research has shown that warm eyes allow swordfishes to process visual information more than 10 times more quickly than eyes cooled to Trophic level The level for the capture of energy Producer, primary consumer, secondary consumer, tertiary consumer, decomposers Basic food chain Food web Shows all of the organisms at each trophic level Connects the organisms to each other on the basis of nutritional dependency Food webs show relationships between trophic level Energy Sunlight is absorbed by pigments in producers Chlorophyll a, chlorophyll b, carotene, xanthophyll, Sunlight Transformation of light energy to chemical energy Light dependent reaction Light absorbed by pigments to generate Pigments arranged in photosystems Photosystem II produces ATP Photosystem I produced NADPH Wavelengths of light Antenna Complex Chlorophyll molecule http://www.uphs.upenn.edu/biocbiop/local_pages/dutton_ Chlorophylls and the absorption of light Carotenoids compared to chlorophylls Arrangement of light capturing structures in chloroplasts Thylakoids Photosystem II on the thylakoids Photosystems Photosystem II http://www.bio.ic.ac.uk/research/barbe r/psIIimages/PSII.html Stomates on leavesuptake CO2 Stomates Carbon fixation http://www.science.smith.edu/departments/Biolog y/Bio231/calvin.html Calvin cycle Decomposers Bacteria and fungi Recycle carbon from dead and decaying organisms Carbon stored in the earth in the form of hydrocarbons Coal - Carbon The Sulfur Cycle Sulfur is apparently always abundant enough to meet the needs of living organisms. Volcanoes and fumaroles emit sulfur dioxide (SO2) and hydrogen sulfide (H2S). These are the natural nonbiological fluxes of sulfur, but they are rare events. Certain marine algae produce dimethyl sulfide (CH3SCH3), which accounts for half of the biotic component of the sulfur cycle. Sulfur plays an important role in global climate. Dimethyl sulfide is the major component of particles in the air, which allow clouds to form. The Sulfur Cycle Humans have altered the sulfur cycle by burning fossil fuels. Acid precipitation is caused by sulfuric and nitric acids derived largely from the burning of fossil fuels. Acidification of lakes in the Adirondack region of New York has reduced fish species richness there. The Clean Air Act Amendments of 1990 have helped reduce acid precipitation in the Eastern United States. Canadian ecologists have shown that lakes can recover from acid conditions if the amount of sulfuric acid is reduced. Figure 58.11 Acidification of Lakes Exterminates Fish Species Figure 58.12 Acid Precipitation Is Decreasing in the Eastern United States The Phosphorus Cycle Phosphorus, a key component of DNA and ATP, is essential for life. Phosphorus does not have a gaseous phase like the other elements. The global phosphorus cycle is very slow (taking millions of years to complete) because the processes of rock formation on the ocean bottom, subsequent uplifting, and weathering of rock into soil all occur slowly. Figure 58.13 The Phosphorus Cycle The Phosphorus Cycle Human activity has affected the phosphorus cycle. About 90 percent of the phosphorus that is mined is used to produce fertilizers and animal feeds. Phosphorus is accumulating in soils at a rapid rate due to fertilizer use. Eutrophication of lakes with phosphorus allows algae and bacteria to multiply, forming blooms. Decomposition of the dead cells occurs after the bloom consumes all oxygen in the lake and anaerobic bacteria take over. Figure 58.14 Phosphorus Is Accumulating in Agricultural Soils The Phosphorus Cycle Lake Erie is a eutrophic lake today, although improved municipal waste handling has reduced the phosphorus level in the lake by 80% from its maximum level. The potential for recovery and recycling of phosphorus is high. The amount of phosphorus contained in sewage and animal wastes could supply major industrial needs. Careful application of fertilizers on agricultural lands can reduce the rate of phosphorus accumulation without reducing crop yields. Interactions among Biogeochemical Cycles Biogeochemical cycles are strongly interrelated. Humans have altered biogeochemical cycles on Earth. Winter typically kills 99 percent of pathogenic organisms. However, global warming is causing warmer winter conditions, which can lead to increased outbreaks of disease. The 1996 assessment report of the Intergovernmental Panel on Climate Change expressed concern about the effects of climate change on human health.