Nutrient Cycling. Hydrologic (Water) Cycle. Nitrogen Cycle: Atmospheric Gases

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1 Nutrient Cycling Laws of Energy and Matter Conservation of Matter In any physical or chemical change, matter is neither created nor destroyed, but merely changes from one form to another Conservation of Energy In any physical or chemical change, energy is neither created nor destroyed, but merely changes from one form to another Law of Energy Degradation Energy moves from an organized, useful form to a disorganized less useful form. Atmospheric Gases Nitrogen 78% Oxygen 21% Argon.93% Carbon Dioxide*.035% Neon.0018% Helium.00052% Methane*.00014% other gases... * these are consider "greenhouse gases" Precipitation Precipitation to ocean Hydrologic (Water) Cycle Evaporation From ocean Evaporation Surface runoff (rapid) Ocean storage Condensation Transpiration from plants Transpiration Groundwater movement (slow) Surface runoff (rapid) Runoff Rain clouds Precipitation Infiltration and Percolation Groundwater movement (slow) Nitrogen Cycle: Forms of Nitrogen: N2 atmospheric nitrogen NO3- nitrate NO2- nitrite NH4+ ammonium NH3 ammonia N2O nitrous oxide NO nitric oxide NO2 nitrogen dioxide CH2N2O urea Nitrogen Fixing: Changing Atmospheric N 2 into usable nitrogen Atmospheric: Lightning: causes N 2 and O to combine in atm. dilute HNO 3 formed and washed to surface. Biological: Nitrogen fixing microorganisms. Specialized bacteria convert gaseous nitrogen to ammonia N 2- +3H 2 - into-- NH 3 (by cyanobacteria in the soil and water and Rhizobium bacteria in small nodules on roots of legume family of plants) Plants can use ammonia and ammonium ions or NO 3 -from the nitrification process below. 1

2 Nitrogen cycle (cont.) The Nitrogen Cycle Nitrification: Changing Urea into usable NO 3 - most of the ammonia in soil is converted by specialized aerobic bacteria to nitrite (NO2-) and then to nitrate ions (NO3-) which plants take up as a necessary nutrient. NH 3, NH + 4 IN SOIL NITROGEN FIXATION by industry for agriculture FERTILIZER S NITROGEN FIXATION bacteria convert to ammonia (NH + 3 ) ; this dissolves to form ammonium (NH + 4 ) loss by leaching uptake by autotrophs FOOD WEBS ON LAND GASEOUS NITROGEN (N 2 ) IN ATMOSPHERE excretion, death, decomposition NITROGENOUS WASTES, REMAINS IN SOIL uptake by autotrophs NO - 3 IN SOIL AMMONIFICATION 2. bacteria, fungi convert NITRIFICATION the residues to NH 3, bacteria convert this dissolves to form NO - 2 to nitrate (NO3 - NH + ) 1. 4 NO - NITRIFICATION 2 IN bacteria convert NH + 4 to nitrate SOIL (NO - 2 ) DENTRIFICATIO N by bacteria loss by leaching The Phosphorus Cycle Plants take up phosphorus from soil using their roots, Phosphorus is mainly in the phosphate form (PO 4 3- ). Plants uptake phosphate and incorporate it into their growth Phosphorous cycles through the ecosystem when plants are eaten, and then the organisms who eat the plants excrete waste or die and decompose. excretion MARINE FOOD WEBS The Phosphorus Cycle uptake by autotrophs death, decomposition sedimentation MARINE SEDIMENTS GUANO weathering DISSOLVED IN OCEAN WATER settling out weathering uplifting over geolgic time mining FERTILIZER DISSOLVED IN SOILWATER, LAKES, RIVERS leaching, runoff uptake by autotrophs death, decomposition ROCKS agriculture LAND FOOD WEBS Human Impact As usual humans have impacted all of the systems noted. Human impacts on nutrient cycles Water Carbon Nitrogen Phosphorus 2

3 Ecosystems/ Ecological Processes I. Definitions II. Factors that Influence Ecosystem A. Population and Regulation B. Range of Tolerance 1. Abiotic Factors 2. Biotic Factor III.Biotic Structure of the Ecosystem A. Food Chains B. Trophic Levels Some definitions Biosphere: all living organisms and their environment Ecosystem: grouping of plants, animals and microbes, etc. interacting with each other and their physical environment "ECO" = home Community: all plants and animals inhabiting an area (suggests interactions) Population: a group of individuals of the same species in an area Species: a group of organisms where all members do or have the potential to interbreed and produce viable offspring The Nature of Ecology Organisms Populations Communities Ecosystems Biosphere Organisms Biosphere Ecosystems Communities Populations Fig. 4.2, p. 72 Factors that Influence Ecosystems Limiting Factors: anything that tends to make it more difficult for a species to live and grow, or reproduce in its environment. Abiotic and Biotic: physical and biological factors can work in concert. Tolerance The degree a certain factor that an organism can withstand is called tolerance. Optimum temperature Range of tolerance Limit of tolerance Env. gradients 3

4 Limiting Factors: Env. gradients Range of optimum ABIOTIC Limiting Factors Population size Lower limit of tolerance No Few organisms organisms Abundance of organisms Upper limit of tolerance Few No organisms organisms temperature water climate/weather soils (mineral component) terrain fire Zone of Zone of intolerancephysiological stress Optimum range Zone of Zone of physiological stressintolerance Low Temperature High BIOTIC Limiting Factors competition: interspecific and intraspecific predation/parasitism amensalism mutualism BIOTIC Limiting Factors competition: interspecific and intraspecific Types of competition Intraspecific (social behavior) Territoriality Social hierarchy Interspecific Competitive exclusion Predator prey interactions Parasitism Amensalism Mutualism Intraspecific (social behavior) Territoriality Social hierarchy 4

5 Agama sp. Color changes to indicate dominant individuals Social hierarchy Familial groups Matriarchal societies 5

6 Interspecific Competition Competitive exclusion Competitive exclusion Predator prey interactions Parasitism Amensalism Mutualism European starling Bromus tectorum Zebra mussels Avoiding/Reducing Competition temporal separation Feeding specializations 6

7 Predator prey interactions Avoiding/ Reducing Competition Behavioral specializations 5,000 Moose population 140 Wolf population Hare 4,000 Lynx Number of moose 120 3, , Year 1, Year Fig. 9.8, p Number of wolves Population size (thousands) Parasitism Amensalism 7

8 Mutualism III. Biotic Structure of the Ecosystem A. Food Chains B. Trophic Levels Biotic Structure of an Ecosystem Producers: (autotrophs) Consumers: (heterotrophs) Primary: Secondary: Tertiary: : Biotic Structure of an Ecosystem Producers: all plants with chlorophyll that photosynthesize: (autotrophs) Consumers: Feed on producers or other (heterotrophs) Primary: feed on producers (herbivores) Secondary: feed on primary (carnivores) Tertiary:.. feed on detritus (usually a bacteria or fungus that feed on dead producers,, etc.) 8

9 Detritus feeders The Biotic Components of Ecosystems Long-horned beetle holes Bark beetle engraving Carpenter ant galleries Termite and carpenter ant work Dry rot fungus Producers (autotrophs) photosynthesis Consumers (heterotrophs) Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Solar energy Wood reduced to powder Mushroom (bacteria, fungus) Producers (plants) Time progression Powder broken down by decomposers into plant nutrients in soil Consumers (herbivores, carnivores) Energy efficiency As we getting higher in trophic levels it takes more energy to maintain the higher levels, on the order of 10X per level. 1% captured by primary producers (99% lost as heat) As energy is transferred through the food chain, energy is lost to heat, therefore only about 10% of energy is actually transferred between trophic levels. 90% lost 90% lost 10% plant energy passes on to herbivores ~10% passed on to primary carnivores ~10% passed on to secondary carnivores Food Webs and Energy Flow Ecological Pyramids Food chains/food Webs First Trophic Second Trophic Third Trophic Fourth Trophic Level Level Level Level Producers Primary Secondary Tertiary (plants) (herbivores) (carnivores) (top carnivores) Solar energy Pyramid of energy flow Ecological efficiency Pyramid of biomass ,000 Tertiary (human) Secondary (perch) Primary (zooplankton) Pyramid of numbers 10,000 Producers Usable energy (phytoplankton) Available at Each tropic level (in kilocalories) Detritvores (decomposers and detritus feeders) Fig. 4.20, p. 85 9

10 Humans Crabeater seal Blue whale Killer whale Sperm whale Elephant seal Food web Complexity Leopard seal Emperor penguin Adélie penguins Petrel Squid Fish Carnivorous plankton Herbivorous zooplankton Krill Phytoplankton 10