iron in deposits of Fe,,. Photosynthetic organisms remove CO, from the atmosphere, thus preventing runaway greenhouse warming of Earths surface Organisms strongly influence bodies of water, producing biomass required for life in the water and mediating oxidation-reduction reactions in the water. Organisms are strongly involved with weathering processes that break down rocks in the geosphere and convert rock matter to soil. Lichens, consisting of symbiotic (mutually advantageous)combinations of algae and fungi, attach strongly to rocks, they secrete chemical species that slowly dissolve the rock surface and retain surface moisture that promotes rock weathering The biosphere is based upon plant photosynthesis, which fixes solar energy (hv) and carbon from atmospheric CO, in the form of high-energy biomass, represented as CH,O) CO2+H,O,CH,O)+O2(g) (14.1) In so doing, plants and algae function as autotrophic organisms, those that utilize solar or chemical energy to fix elements from simple, nonliving inorganic material into complex life molecules that compose living organisms. The opposite process biodegradation, breaks down biomass either in the presence of oxygen(aerobic respiration), (CH2O1+O2(8),CO,+ H,O (14.2) or absence of oxygen(anaerobic respiration 2ICH,O)->CO,(g)+ Ch(g) (14.3) Both aerobic and anaerobic biodegradation get rid of biomass and return carbon ioxide to the atmosphere. The latter reaction is the major source of atmospheric methane. Nondegraded remains of these processes constitute organic matter in aquatic sediments and in soils, which has an important influence on the characteristics of these solids. Carbon that was originally fixed photosynthetically forms the basis of all fossil fuels in the geosphere There is a strong interconnection between the biosphere and the anthrosphere Humans depend upon the biosphere for food, fuel, and raw materials. Human influence on the biosphere continues to change it drastically. Fertilizers, pesticides, and cultivation practices have vastly increased yields of biomass, grains, and food Destruction of habitat is resulting in the extinction of vast numbers of species, in some cases even before they are discovered. Bioengineering of organisms with recombinant DNA technology and older techniques of selection and hybridization are causing great changes in the characteristics of organisms and promise to result in even more striking alterations in the future. It is the responsibility of humankind to make such changes intelligently and to protect and nurture the biosphere Ecology Ecology is the science that deals with the relationships between living organisms with their physical environment and with each other. 4 Ecology can be approached C 2000 CRC Press llciron in deposits of Fe2O3. Photosynthetic organisms remove CO2 from the atmosphere, thus preventing runaway greenhouse warming of Earth’s surface. Organisms strongly influence bodies of water, producing biomass required for life in the water and mediating oxidation-reduction reactions in the water. Organisms are strongly involved with weathering processes that break down rocks in the geosphere and convert rock matter to soil. Lichens, consisting of symbiotic (mutually advantageous) combinations of algae and fungi, attach strongly to rocks; they secrete chemical species that slowly dissolve the rock surface and retain surface moisture that promotes rock weathering. The biosphere is based upon plant photosynthesis, which fixes solar energy (hn) and carbon from atmospheric CO2 in the form of high-energy biomass, represented as {CH2O}: hn CO2 + H2O ® {CH2O} + O2(g) (1.4.1) In so doing, plants and algae function as autotrophic organisms, those that utilize solar or chemical energy to fix elements from simple, nonliving inorganic material into complex life molecules that compose living organisms. The opposite process, biodegradation, breaks down biomass either in the presence of oxygen (aerobic respiration), {CH2O} + O2(g) ® CO2 + H2O (1.4.2) or absence of oxygen (anaerobic respiration): 2{CH2O} ® CO2(g) + CH4(g) (1.4.3) Both aerobic and anaerobic biodegradation get rid of biomass and return carbon dioxide to the atmosphere. The latter reaction is the major source of atmospheric methane. Nondegraded remains of these processes constitute organic matter in aquatic sediments and in soils, which has an important influence on the characteristics of these solids. Carbon that was originally fixed photosynthetically forms the basis of all fossil fuels in the geosphere. There is a strong interconnection between the biosphere and the anthrosphere. Humans depend upon the biosphere for food, fuel, and raw materials. Human influence on the biosphere continues to change it drastically. Fertilizers, pesticides, and cultivation practices have vastly increased yields of biomass, grains, and food. Destruction of habitat is resulting in the extinction of vast numbers of species, in some cases even before they are discovered. Bioengineering of organisms with recombinant DNA technology and older techniques of selection and hybridization are causing great changes in the characteristics of organisms and promise to result in even more striking alterations in the future. It is the responsibility of humankind to make such changes intelligently and to protect and nurture the biosphere. Ecology Ecology is the science that deals with the relationships between living organisms with their physical environment and with each other.4 Ecology can be approached © 2000 CRC Press LLC