Ecology.pdf
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abiotic environmental necessary growth and factors physiology Nutrients Nutrients are substances necessary for healthy physiology of organisms Principle of limiting factors: growt...
abiotic environmental necessary growth and factors physiology Nutrients Nutrients are substances necessary for healthy physiology of organisms Principle of limiting factors: growth may be determined by the factor in shortest supply Loading… ‹#› Nutrients Nutrients are often growth-limiting environmental factors E.g. Phosphorus and nitrogen often limit productivity in aquatic ↳ huge blooms ↳ influx of nutrients ecosystems; input of ↳ effect aquatic organisms these nutrients can stimulate algal growth Phytoplankton bloom west of Vancouver Island in response to nutrient upwelling FIGURE ‹#› 4.1 Macronutrients Macronutrients are nutrients required in large quantities: Vital part of biomolecules Carbon, Oxygen, Loading… Hydrogen: the basis most organic molecules of Other macronutrients are called mineral nutrients: Nitrogen, Phosphorus, Sulfur, Mineral nutrient Calcium, Magnesium, availability often limits Potassium plant productivity ‹#› potentially limiting Micronutirents Micronutrients are nutrients needed in very low quantities: Iron, Manganese, Boron, Zinc, Chlorine, Sodium, Copper, Nickel, Molybdenum Lack of micronutrients can lead to deficiency syndromes Paadies Low copper can lead to root or stem breakage ‹#› The importance of nutrients Protein Heme Macronutrients are chain Iron (Fe2+) important parts of molecules: amino acid > - any E.g. Nitrogen in proteins; phosphorus in phospholipids Micronutrients are needed in low amounts E.g. Iron is a critical Hemoglobin consists of component of proteins and heme (rich in hemoglobin nitrogen) and iron; iron deficiency leads to anemia ‹#› X106 TABLE 4.1 ‹#› DATA Toxicity Some essential micronutrients become toxic at high concentrations - E.g. Nickle and copper can stunt growth at high Contro I quantities l Level of toxicity don't depends on the have a lot of leaves organism and root mass High Copper, Nickel ‹#› Nickle Tolerance Long exposure to toxic substances can lead to evolution of tolerant organisms Loading… E.g. Mangroves have evolved salt tolerance Store inside leafs - to not disrupt systems E.g. Plants may develop tolerance to toxic levels of metals 100 years of exposure to metals in Sudbury’s soils have lead to some tolerant plants ‹#› Hyperaccumulation Some plants neutralize toxic substances by accumulating - them in their vacuoles E.g. Mangroves, metal hyperaccumulators - Bioremediation exploits this property of plants to help collect pollutants have toxins in vacuoles plants accumulate and harvest plants bottle them up Phytoremediation: plants to clean soil, air, water ‹#› Energy transfer vs nutrient cycles photosynthesis and Life needs continuous grab take sunlight energy and input of new energy use to bonds build carbon (Lecture 3) LIFE ON EARTH FUEL - Nutrients, in contrast, are cycled over and over (Lecture 4) all micronutrients/ macronutrients on earth E.g. Canada geese obtain nutrients from grass, and their feces fertilize the grass ‹#› Nutrient budgets Nutrient cycles have nutrient budgets: into of earth i get living part Input Transformations consumer accessible expel in ii earth Output Compartments Atmospheric ii gasses i Organic pool. Available nutrients iv Rocks and Soil ‹#›. Rocks and soil Nutrient budgets FIGURE ‹#› Carbon cycle Carbon: backbone of life, serving as the most important structural molecule for life Carbon (CO2) is fixed from the atmosphere through photosynthesis Carbon is released (CO2) through decomposition and respiration Carbon is stored in living biomass, in Storage as biomass (e.g. litter, and in peat peat, coal, oil, gas) ‹#› carbon available CARBON IS EVERYWHERE - in air 6 ↳ abundant in rocks of plants need CO2 drive = photosynthesis earth (liquid solid) , FIGURE ‹#› 4.4 Carbon: Atmospheric carbon Seasonal variation in living biomass in temperate zones results in fluctuation of atmospheric carbon FIGURE ‹#› 4.5 Carbon: Methane In low-oxygen conditions, organic material decomposes slowly Carbon is produced as CO2 or CH4 (methane) Methane is produced by bacteria, by fossil fuel combustion, and by flatulent autotrophs ↳ heterotrophs - farting animals ↳ cows ↳ a lot of Cellulose ‹#› Carbon: Anthropogenic effects Use of fossil fuels and land cover changes have produced a massive increase in CO2 Fossil fuel use changes Earth’s carbon cycle ‹#› need make and nitrogen Amino to acids Nitrogen cycle proteins Nitrogen: A critical component of all proteins Nitrogen is often growth-limiting Some forms of nitrogen (Nitrate NO3- and ammonium NH4+) are plant-available nutrients N2 is not available Nitrogen in dog urine ↳ makes grass greener hard to break (lot energy ( of ‹#› is found in the Nitrogen atmosphere ↳ N2 useless needs to be broken FIGURE ‹#› 4.7 Nitrogen: Fixation Atmosphere: 78% N2 - N2 is stable, but not accessible to most organisms Nitrogen fixation is the conversion of atmospheric N2 to biologically useful nitrogen takesNo m the atmosphere Clover: a local nitrogen-fixing plant and in the roots splits N2 to apart forms of N2 produce biologically useful ‹#› Nitrogen: Fixation Nitrogen is fixed by bacteria, free-living or in symbiosis with plant hosts Nitrogen is fixedLoading… through oxidation by lightning Spite Nitrogen can be fixed industrially (this technology allowed the agriculture to uncouple from manure farming) Bean: another local nitrogen-fixing plant ‹#› Nitrogen: Fixation by legumes ↓ In legume plants Root nodules contain Rhizobium and Bradyrhizobium bacteria Nitrogen fixation is an energy-rich process, but it provides a competitive advantage for a plant under nitrogen-limited conditions Nitrogen-fixing root nodules of a pea plant FIGURE ‹#› 4.9 Phosphorus cycle Phosphorus: a critical component of adenosine triphosphate (ATP), the energy source of cells, among other biomolecules Phosphorus is often growth-limiting in lakes Phosphorus influx can lead to eutrophication ‹#› Phosphorus found in the earth deep at and ends up ↳ moves down ecosystems bottom ↳ heavy or of apart heavy substances ‹#› Phosphorus cycle Most phosphorus is contained in marine sediments No phosphorus in the atmosphere One-way transport from land to ocean sediments, while passing through organisms ‹#› Phosphorus from ocean bird or on a poop Animals, · especially birds, act as biovectors for phosphorus Migratory fish that move out of the ocean transport phosphorus I 9 - provide phosphorus bear needs poop = release salmon from deep ocean ‹#› & extract from bird rock phosphorus on poop ↳ belt to us conveyor ↳ natural resource overexpose ↳ no more island LONG 3 is phosphorus cycle z The Pacific island nation of Nauru‹#› Sulphur cycle contained in earth Sulphur: a critical component of proteins and other biochemicals Gaseous sulphur is emitted by volcanos Some sulphur is produced by bacteria ‹#› ‹#› acid rain more sulphur into atmosphere Sulphur: acid rain 78% of global SO2 emissions are Hung anthropogenic: Combustion of fossil fuels Smelting of sulphide- rich ores SO2 reacts in the atmosphere and turns to sulphuric acid or acid rain ‹#› Soil Soil is the foundation of terrestrial ecosystems Rocky fragments and other minerals, nutrients, organic matter, water, gasses, organisms Provide physical support in terrestrial ecosystems Ecosystems with plant roots, bacteria, protists, invertebrates, earthworms, and other organisms FIGURE ‹#› 4.15 Soil structure Clay-dominated soils drain poorly Sandy soils drain well, but prone to drought Organic matter (humus) increases water- and nutrient-holding capacity (tilth) ‹#› Soil structure Soil designations Coarse gravel (>20 mm) Gravel (2-20 mm) Sand (0.05-2 mm) Silt (0.002-0.05 mm) Clay (
