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Sustaining Life Since the Earth is a closed system, there are two key factors to sustain life on earth: 1. Energy: The Sun 2. Nutrient cycles: Nutrients have to alternate between the biotic and the abiotic components of the environment, for this to happen; there has to...

Sustaining Life Since the Earth is a closed system, there are two key factors to sustain life on earth: 1. Energy: The Sun 2. Nutrient cycles: Nutrients have to alternate between the biotic and the abiotic components of the environment, for this to happen; there has to be life and death Life Death  1.3 Describe how matter cycles among the living and nonliving parts of an ecosystem The Water Cycle Water continuously moves between the oceans, the atmosphere, and land—sometimes outside living organisms and sometimes inside them. Water molecules typically enter the atmosphere as water vapor when they evaporate from the ocean or other bodies of water. Water can also enter the atmosphere by evaporating from the leaves of plants in the process of transpiration. Some groundwater penetrates deeply enough into the ground to become part of underground reservoirs. Nutrient Cycles What is the importance of the main nutrient cycles? Every organism needs nutrients to build tissues and carry out life functions. Like water, nutrients pass through organisms and the environment through biogeochemical cycles. Nutrients pass through organisms and the environment through biogeochemical cycles. The three pathways, or cycles, that move carbon, nitrogen, and phosphorus through the biosphere are especially critical for life  1.2.3 Describe how the availability of nutrients affects the productivity of ecosystems Nutrient Limitation in Soil All nutrient cycles work together like the gears shown. If any nutrient is in short supply—if any wheel “sticks”—the whole system slows down or stops altogether. 1.2.3 Describe how the availability of nutrients affects the productivity of ecosystems Nutrient Limitation in Soil The growth of crop plants is typically limited by one or more nutrients that must be taken up by plants through their roots. Most fertilizers contain large amounts of nitrogen, phosphorus, and potassium, which help plants grow better in poor soil. Carbon is not included in chemical fertilizers because plants acquire carbon dioxide from the atmosphere. Micronutrients such as calcium, magnesium, sulfur, iron, and manganese are necessary in relatively small amounts, and are sometimes included in specialty fertilizers. 1.2.4 Build representations graphs, using data from ecological observations, about matters cycles 1.2.4 Build representations graphs, using data from ecological observations, about matters cycles  Carbon Carbon is stored on our planet in the following major pools: as organic molecules in living and dead organisms found in the biosphere; as the gas carbon dioxide in the atmosphere; as organic matter in soils; in the lithosphere as fossil fuels and sedimentary rock deposits such as limestone, dolomite and chalk; in the oceans as dissolved atmospheric carbon dioxide and as calcium carbonate shells in marine organisms. Photosynthesis versus respiration? Photosynthesis Plants are solar panels (They capture the sun light) 6H2O + 6CO2 + E (Sunlight) C6H12O6 (sugar) + 6O2 Respiration The body burns food (sugar) to get energy 6O2 + C6H12O6 (sugar) 6CO2 + 6H2O + energy  The Carbon Cycle Includes two main processes: O2 Respiration Photosynthesis CO2 The Carbon The Carbon Cycle The Carbon Cycle 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles  Nitrogen Nitrogen is an essential element for the growth of plants and animals. Like carbon, nitrogen passes along food chains and circulates between the biotic and abiotic parts of the environment. Plants can obtain nitrogen naturally or through the use of fertilizers.  N How does N atmospheric nitrogen get changed into a form that can be used by most living organisms?  N What is N “nitrogen fixation” and what does it mean to say nitrogen gets “fixed”? There are three ways that nitrogen gets “fixed”! (a) Atmospheric Fixation (b) Industrial Fixation (c) Biological Fixation Bacteria  Lightning “fixes” Nitrogen! Atmospheric Fixation (Only 5 to 8% of the Fixation Process) The enormous energy of N N O lightning breaks nitrogen Nitrogen molecules apart and enables Nitriteion combines the nitrogen atoms to combine with Oxygen with oxygen forming nitrogen Nitrogen oxides forms oxides (N2O). Nitrogen oxides (N2O) Nitrogen dissolve in rain, forming (NO3) oxides dissolve nitrates. Nitrates (NO3) are in rain and carried to the ground with the change to rain. nitrates Plants use nitrates to grow!  NN H Industrial Fixation N Under great pressure, at H3 a temperature of 600 degrees Celcius, and with the use of a Industrial Plant combines nitrogen and hydrogen catalyst, atmospheric nitrogen (N2) and Ammonia is formed (NH3) hydrogen are combined to form ammonia (NH3). Ammonia can be used as a fertilizer. Ammonia is used as a fertilizer in soil Biological Fixation (where MOST nitrogen fixing is completed) There are two types of “Nitrogen Fixing Bacteria” Free Living Bacteria (“fixes” 30% of N2) Symbiotic Relationship Bacteria (“fixes” 70% of N2) Nitrogen fixation: Is the process of pulling nitrogen from the air and bonding it to other elements to make new compounds, such as NH3 and NH4+. In nature nitrogen fixation is carried out by nitrogen fixing bacteria that live in the soil or water, the most important of these bacteria is called Rhizobia, which live in the nodules (rounded swellings) of legumes (beans, peas & clover). In oceans this is done by Cyanobacteria Nitrogen fixation could also occur naturally through lightening in limited amounts 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles Nitrogen Fixation Nodules on plant roots 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles N2O The Nitrogen Cycle 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles 1. Nitrogen Fixation: Summarize the + 15.10 main steps in N2 NH3 and NH4 nitrogen and cycles + 2. Nitrification: the oxidation of the NH4 ion + - - NH4 NO2 NO3 - 3. Denitrification: the reduction of NO3 ion Recognize the - importance of NO3 N2O N2 15.11 bacteria in the process of nitrogen fixation 4. Ammonification: Amino Acids NH3 The Phosphorus Cycle Phosphorus forms a part of vital molecules such as DNA and RNA. Although phosphorus is of great biological importance, it is not abundant in the biosphere. The Phosphorus Cycle Phosphorus in the form of inorganic phosphate remains mostly on land, in the form of phosphate rock and soil minerals, and in the ocean, as dissolved phosphate and phosphate sediments. 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles 1.2.5 Analyze data to relate the cycles of matters and homeostasis including water, carbon, nitrogen and phosphorous cycles The Phosphorus Cycle Plants bind phosphate into organic compounds when they absorb it from soil or water. Organic phosphate moves through the food web, from producers to consumers, and to the rest of the ecosystem. Other phosphate washes into rivers and streams, where it dissolves. This phosphate eventually makes its way to the ocean, where marine organisms process and incorporate it into biological compounds. In oceans inorganic phosphate sediments form then over geological time get uplifted where the get exposed to weathering. Nutrient Limitation How does nutrient availability relate to the primary productivity of an ecosystem? Nutrient Limitation Ecologists are often interested in an ecosystem’s primary productivity—the rate at which primary producers create organic material. If an essential nutrient is in short supply, primary productivity will be limited. The nutrient whose supply limits productivity is called the limiting nutrient.