Nutrient Cycles 2023 with 100% correct questions and answers

nitrogen cycle nutrient cycle in which the ultimate source in the atmosphere (huge gas pool); proximate sources are nitrogen-fixation and lightning; oxidation potential determines which reactions in the cycle are important (via microbes); there are many forms because of many oxidation states; human additions can cause eutrophication ammonification the process of turning inorganic nitrogen into ammonia; aerobic, energy releasing oxidations assimilatory nitrogen reduction the process of turning nitrate (NO3)(most oxidized) into organic nitrogen (most reduced); requires energy denitrification process of removing oxygen (NO3-NO2- NO) and can ultimately lead to N2; may be from pseudomonas; anaerobic reduction reactions coupled to energy releasing oxidations; returns N2 to atmosphere nitrification process of adding oxygen (NO2-NO3) by nitrobacteria, nitrococcus; aerobic, energy releasing oxidations nitrogen fixation process of turning molecular nitrogen (N2) into ammonia by rhizobium, azotobacteria, and cyanobacteria; characterized as an anaerobic reduction reactions coupled to energy releasing oxidations phosphorous cycle relatively simple cycle due to fewer oxidation states, although plants primarily uptake PO4; control of availability is complex because: at low pH, P unavailable by binding to clay, Fe, Al in soil; mycorrhizae important scavengers of P from soils- important mutualists; in high O2 systems, P precipitates out of water, constituting constant rate of loss from ecosystems assimilatory processes causing carbon cycling with living things by incorporating elements into cell protoplasm dissimilatory processes causing carbon cycle that use living things as source of energy to produce ATP (e.g. heterotrophs) carbon cycle has three classes of processes that cause cycling by living things, exchange of CO2 between atmosphere, oceans; sedimentation, precipitation of carbonates in water; consumption of fossil fuels increases atmospheric CO2; global warming causes increased plant carbon uptake (from warming, greater CO2 concentrations), but even greater release of C from tundra mineralization chemical, dissimilatory reactions that convert nutrients from organic to inorganic form acid precipitation low pH of rain, snow that is caused by human activities such as combustion of fossil fuels and other industrial processes that put nitrous oxides, sulfur oxides, into the atmosphere; affects plants, animals both directly (acid burns) and indirectly (altered soil nutrient availability) regeneration processes via soil processes that decompose organic matter in terrestrial ecosystems; in water via mixing of nutrient rich sediments; diverse factors affect control and depends on ecosystem such as weathering rate of mineral soils and decomposition rate of plant/animal material hydrological cycle cycle that controls many other nutrient cycles through the movement of water (see previous lectures) turnover time pool size/flux; low movement of nitrogen causes low time due to how tightly N is held and cycled by organisms watershed used to test hypothesis that nutrients are held tightly by ecological uptake by organisms; was clear cut and harvested to disrupt biological activity; nutrient inputs and outputs measured; tight bedrock allowed all outputs to be measured in streams; found that nitrogen levels became unsafe, so important to scale back on tree cutting limiting nutrient nutrients that are limited in certain ecosystems and the atmosphere due to differing nutrient cycles that are altered by interactions by biological activities, especially humans atmospheric cycles cycles of certain nutrients in the atmosphere including carbon, nitrogen, phosphorous cycles nutrient pools may be organic or inorganic with differing sizes; a certain portion or area of a nutrient cycle in which certain processes occur nutrient fluxes the movement of certain materials between pools with certain controls and capacity for transformations; carbonate chemistry seen specifically when the uptake of CO2 pushes reaction to the left, causing calcium carbonate sedimentation; can cause formation of coral reefs; see formula in handout compartmental model generalized model that shows all nutrient cycles moving from organic - inorganic forms and more biological, faster processes to geological, slower processes sedimentary cycles cycles of the movement of nutrients through sediment; may be influenced greatly by biological organismes nutrient cycling the movement of nutrients through the atmosphere and into sediment, in which nutrients take many different forms and can be influenced by biological activity; Cycles include nitrogen, oxygen, and phosphorous