The Carbon Cycle

Nutrient Cycles & ThermodynamicsDO NOWDraw the hydrologic cycleLabel all parts of your diagramBiogeochemical Nutrient CyclesBiogeochemical Nutrient CyclesHydrologicCarbon-OxygenNitrogenPhosphorusSulfurRockdescribe the flow of essential elements from the environment, through living organisms, and back into the environmentBiogeochemical CyclesHydrologic Cycle

The hydrologic cycle

Hydrologic Cycle(water cycle)1. Reservoir oceans, air (as water vapor), groundwater, lakes and glaciers; evaporation, wind and precipitation (rain) move water from oceans to land2. Assimilation plants absorb water from the ground, animals drink water or eat other organisms which are composed mostly of water3. Release plants transpire, animals breathe and expel liquid wastesReserviors

Residence Times

The carbon-oxygen cycle

Carbon-Oxygen Cycle(carbon is required for building organic compounds)1. Reservoir atmosphere (as CO2), fossil fuels (gas, oil, coal), durable organic materials (for example: cellulose).2. Assimilation plants use CO2 in photosynthesis; animals consume plants3. Release plants and animals release CO2 through respiration and decomposition; CO2 is released as wood and fossil fuels are burned

The nitrogen cycle

Nitrogen Cycle(Nitrogen is required for the manufacture of amino acids and nucleic acids)1. Reservoir atmosphere (as N2); soil (as NH4+ or ammonium, NH3 or ammonia, N02- or nitrite, N03- or nitrate2. Assimilation plants absorb nitrogen as either NH4+ or as N03-, animals obtain nitrogen by eating plants and other animals. The stages in the assimilation of nitrogen are as follows:Nitrogen Fixation: N2 to NH4+ by nitrogen-fixing bacteria (prokaryotes in the soil and root nodules), N2 to N03- by lightning and UV radiation.Nitrification: NH4+ to N02- and N02- to N03- by various nitrifying bacteria.

Nitrogen Cycle3. Release Denitrifying bacteria convert N03- back to N2 (denitrification); detrivorous bacteria convert organic compounds back to NH4+ (ammonification); animals excrete NH4+ (or NH3) urea, or uric acid.

Nitrogen Cycle

The phosphorus cycle

Phosphorus Cycle(Phosphorus is required for the manufactureof ATP and all nucleic acids)1. Reservoir erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processes2. Assimilation plants absorb inorganic PO43- (phosphate) from soils; animals obtain organic phosphorus when they plants and other animals3. Release plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste productsThe sulfur cycle

Sulfur Cycle(Sulfur is required for the manufacture of proteins)1. Reservoir Earths crust as gypsum (CaSO4) and pyrite (FeS2), oceans as sulfate anions, atmosphere as sulfur dioxide (SO2) 2. Assimilation sulfate (SO4 2) is reduced by plants, fungi and prokaryotes3. Release plants and animals release sulfur when they decompose

The rock cycleRock cycle = The heating, melting, cooling, breaking and reassembling of rocks and mineralsRocks help determine soil chemistry, which influences ecosystemsHelps us appreciate the formation and conservation of soils, mineral resources, fossil fuels, and other natural resources2525Hypoxia and the Gulf of Mexicos Dead ZoneObservations: low oxygen levels - hypoxiaHypothesis: caused by nutrients (fertilizers) that ran into the Gulf from riversExperiments: monitoring oxygen (long term), water sampling (N, NaCl. Bacteria, phytoplankton); observed life; analyzed historical dataResults: phytoplankton receiving too much phosphorus from farming & sewage treatment plantsAs the phytoplankton die the decomposers use up available oxygenSolution: reduce amount of phosphorus entering the Gulf but How?Newtons LawsConservation of Mass mass cannot be created or destroyed, but can be changed to energyNewtons Laws - FirstThermodynamics inertia an object in motion stays in motion unless acted upon by an outside forceNewtons Laws - SecondThermodynamics entropy disorder increasesThink of entropy as heat lossWe must add more energy to compensate for the heat lossEnergy passes through trophic levelsOne of the most important species interactions is who eats whomMatter and energy move through the communityTrophic levels = rank in the feeding hierarchyProducersConsumersDetritivores and Decomposers

3030Producers: the first trophic levelAutotrophs (self-feeders) = organisms that capture solar energy for photosynthesis to produce sugarsGreen PlantsCyanobacteriaAlgaeChemosynthetic bacteria use the geothermal energy in hot springs or deep-sea vents to produce their food3131Consumers: organisms that consume producersPrimary consumers = second trophic levelOrganisms that consume producersHerbivores consume plantsDeer, grasshoppersSecondary consumers = third trophic levelOrganisms that prey on primary consumersCarnivores consume meat Wolves, rodents, birds3232Consumers occur at even higher trophic levelsTertiary Consumers = fourth trophic levelPredators at the highest trophic levelConsume secondary consumersAre also carnivoresHawks, owlsOmnivores = consumers that eat both plants and animalsDetritivores and decomposersOrganisms that consume nonliving organic matterEnrich soils and/or recycle nutrients found in dead organismsDetritivores = scavenge waste products or dead bodiesMillipedesDecomposers = break down leaf litter and other non-living materialFungi, bacteriaEnhance topsoil and recycle nutrients3434Energy, biomass, and numbers decreaseMost energy organisms use is lost as waste heat through respirationLess and less energy is available in each successive trophic levelEach level contains only 10% of the energy of the trophic level below itThere are far fewer organisms at the highest trophic levels, with less energy available

A human vegetarians ecological footprint is smaller than a meat-eaters footprint3535Pyramids of energy, biomass, and numbers

Food webs show relationships and energy flowFood chain = the relationship of how energy is transferred up the trophic levels Food web = a visual map of feeding relationships and energy flowIncludes many different organisms at all the various levelsGreatly simplified; leaves out the majority of species

3737Some organisms play big rolesKeystone Species = has a strong or wide-reaching impact far out of proportion to its abundanceRemoval of a keystone species has substantial ripple effects Alters the food chain

Species can change communitiesTrophic Cascade = predators at high trophic levels can indirectly affect populations of organisms at low trophic levels by keeping species at intermediate trophic levels in checkExtermination of wolves led to increased deer populations, which led to overgrazed vegetation and changed forest structureEcosystem engineers = physically modify the environmentBeaver dams, prairie dogs, fungi, insects, phytoplankton