Chapter 8

Chapter 8The BiosphereThe BiosphereThe Biosphere is the layer of the Earth containing organisms and their habitats.Associated with the biosphere are the biogeochemical cycles of essential elements for life.

Biogeochemical Cycles Would anyone happen to know what a biogeochemical cycle is?3Biogeochemical CycleA set of processes by which an element passes from one environment to the next and eventually returns to its original environment.Carbon CycleNitrogen CyclePhosphorous CycleWhy Carbon so important all bio-molecules contain carbon Proteins carbohydrates lipids DNA all have a backbone of carbon with different functional groups attached4The Carbon CycleCarbon is often described as the building block of life, since it is the basic element of proteins, lipids and carbohydrates, and thus all living things.Carbon is constantly being exchanged and recycled through different parts of the Earth.

Looking at natural processes first: photosynthesis + respiration6

Photosynthesis: plants and phytoplankton take in carbon dioxide (CO2) from the atmosphere and use it to make sugars.Respiration: when living organisms breath they release carbon dioxide back into the atmosphere.

Stages of the Carbon CycleCO2CO2Stages of the Carbon CycleDecomposition: organisms called decomposers break down dead organisms and animal waste, releasing CO2 or methane in the process.

CO2, methaneStages of the Carbon CycleOcean Sediment: Carbon dioxide from the atmosphere dissolves in oceans to form bicarbonate. This is used by marine organisms to create their shells and skeletons, which sink to the ocean floor when they die, and accumulate in the sediment, eventually forming carbonate rock.

CO2Stages of the Carbon CycleFossil fuels: When dead plant and animal matter are buried under sediment, they are converted into oil, coal or natural gas after millions of years. The burning of these fossil fuels by humans releases carbon dioxide into the atmosphere.

Stages of the Carbon CycleVolcanic eruptions and forest fires: Also release carbon into atmosphere.

CO2CO2

112 Decomposers344Carbon into the atmosphere (CO2) Carbon out of the atmosphereCarbon into the groundRespiration animals plants (at night) decomposers (also methane)photosynthesisSedimentary rock formationForms from sediments of marine organisms

volcanoes

Carbon dioxide dissolves in water Is incorporated into shells and skeletons of marine organisms. Fossil fuel formationForms from organic matter in bogs and marshesBurning something Forrest fires Fossil fuels

Carbon passed around from organism to organism in food chains

112 Decomposers344The Nitrogen CycleThe nitrogen cycle is the biogeochemical cycle that describes all the exchanges of nitrogen on earth.

The Nitrogen CycleThe vast majority of nitrogen is found in the atmosphere, as N2, which cannot be directly used by plants or animals.

The Nitrogen CycleNitrogen is used by living organisms to produce a number of complex organic molecules like amino acids, proteins and DNA.

Nitrogen is normally the most limiting nutrient for plant growth.

Stages of the Nitrogen CycleNitrogen fixation:ammoniumN2Bacteria in soil (or associated with plant roots) convert N2 into ammonia, which reacts with water to ammonium.

Clover, lupins, peanuts, legume family19Stages of the Nitrogen CycleNitrification: bacteria convert ammonium into nitrites, then into nitrates.

Stages of the Nitrogen CycleNitrogen absorption (Assimilation): plants absorb nitrates or ammonium from soil or water and use it to create proteins. Animals can then get their nitrogen by eating the plants.

Stages of the Nitrogen CycleDecomposition of waste: decomposers break down dead organisms and animal waste, producing ammonia which dissolves to form ammonium.

ammonium

Stages of the Nitrogen CycleDenitrification: certain bacteria can convert nitrates into atmospheric nitrogen.

N2

Stages of the Nitrogen CycleN2Nitrogen fixationN2DenitrificationNitrificationNitrogen absorptionNitrogen recycling(Decomposers)Nitrogen into groundNitrogen convertedNitrogen passed between organismsNitrogen out of groundNitrogen fixation(bacteria in soil and on plant roots)NitrificationBacteria convert Ammonium to NitrateNitrogen absorption by plantsAnimals eat plants or animalsDecomposersBreak down plant and animals wasteDenitrificationBacteria convert nitrates in nitrogen

121534The Phosphorous Cycle - ESTPhosphorous (like nitrogen) is a component of DNA and is therefore an essential element or all life.

Bone consists predominantly of a mineral containing phosphate.P why important -> in DNA and bones27Stages of the Phosphorous CycleWeathering of rock: water dissolves phosphorous in the form of phosphate. Phosphate is transported by water.

From where do we get phosphorous in the first place? from rock28Stages of the Phosphorous CycleAbsorption by living organisms. Plants absorb phosphates, animals eat plants or other animals.

Stages of the Phosphorous CycleDecomposition of wasteReturn of Phosphorous to the soil through animal wastedecomposers

PhosphatePhosphateStages of the Phosphorous CycleProliferation of plankton and sedimentationPhosphate in water promotes the growth of plankton eaten by animalsPhosphate minerals precipitate sedimentary rock

1234Unlike in carbon and nitrogen cycle atmosphere here not part of the cycle, only hydrosphere and lithosphere and biosphere32Terrestrial BiomesBiome: a distinct ecological community of plants and animals living together in a particular climate.Definition of a biome?Need to define climate what plays into climate?33Factors contributing to climate

LatitudeAltitudeClimate- TemperatureThe main factors which influence temperature are:1. Latitude: as you move away from the equator, sunlight is less intense lower temperature.2. Altitude: with increases in elevation at a given latitude, the temperature decreases.

Climate- TemperatureTemperature plays a vital role because most organisms are adapted to live within a very narrow temperature range. Increasing or decreasing the temperature by even a few degrees can cause some species to die.

Factors affecting Terrestrial BiomesLatitudeAltitudeSolar energyTemperaturePrecipitationSoil typeWindsProximity to bodies of water

Solar energy not only temperature but also how much light there is, latitude, whether there are seasons 37

Hadley Cells and climate zonesHot moist air rises at the Equator (1) air cools and water condenses, it rains (2)Dry air moves towards 30, sinks and warms up (3).Dry hot air moves back towards Equator, collecting all water from the land underneath (4) DesertLatitude determines how much it rainsAlso where Ferrel and Polar Cell meet warm moist air rises:

water condenses rain.

Influence of Altitude on precipitation

Andes (mountain chain)West wind zoneDesert in wind shadowClimate- PrecipitationPlays a vital role because all living organisms require water

Climate- PrecipitationPrecipitation tends to be generally higher where air is rising & cooling, releasing moisture:near the equator, most significantly- produces tropical rainforests or tropical seasonal forestsat 60o N & S latitude, to lesser extent- produces temperate deciduous forests, temperate rainforests, coniferous forests.

Climate- PrecipitationPrecipitation tends to be generally lower:near 30 o N & S latitude- dry, descending air masses produce deserts (all great world deserts lie near 30 o N or S latitude)in interiors of large continents- due to great distance from sea (ultimate source of most moisture)Terrestrial Biomes: Can you name these?

Tropical RainforestBoreal ForestArctic TundraDesertDesert

Tropical ForestsLie on either side of the equator (warm temperatures)High precipitationContain over half of the worlds terrestrial biodiversitySoil rather infertile due to leaching (excessive rain), and very fast decomposition of organic matter.

Seasonal tropical rain forestMainly in AfricaDry season of varying length

Temperate ForestsContain mix of deciduous and coniferous treesNutrient rich soils make an excellent habitat for plant growth and animals

Warm and cold season Precipitation evenly throughout yearBoreal Forest/TaigaComposed mostly of coniferous trees, which do not lose leaves/needlesAcidic, nutrient poor soilsLong, cold winters; short, cool summers

Taiga: trees become shorter and more scarceGrasslands/Shrublands

Dry, without enough rainfall to support tree growth, but enough for grasses and shrubsThere are three different types:Temperate grasslands hot summers, cold winters great plains north americaSavannas- hot year-round; rain in summer, dry winterDerived grasslands- farmers grain or grass fields

Arctic TundraSurrounds the North Pole, with long, cold winters and short summers. Characterized by slow plant growth and extensive permafrostGrasses, bushes, moss and lichensSome fauna: ex. caribou, arctic fox

DesertsDefined as areas with less than 25cm of annual precipitationVery high or very low temperatures (ex. Antarctica)Rare plant life and very few animals, which have adapted to desert life

AlpineBiomes that are found on mountain rangesAs altitude increases, temperature decreases, which changes vegetation:Submontane zone (below 1300m): deciduous treesMontane zone (1300-1800m): deciduous/coniferous treesSubalpine zone (1800-2400m): some conifersAlpine zone (above 2400m): few bushes and grassesNival zone (above 3000m): below freezing point, only some lichen can grow here

Aquatic BiomesFreshwater BiomesLakesBodies of water surrounded by landslow current, deep water Flora/Fauna consists of microorganisms, plants, plankton, fish, amphibians, reptiles and birds.

Freshwater BiomesRiversDrainage channels for surface waterAquatic plants must be adapted to the current and highly oxygenated water.Often lined by mosses and grasses.

Freshwater BiomesWetlandsAreas permanently or temporarily covered with water (fresh or salt)Marshes: land covered with stagnant water, no treesSwamps: land covered with water but with trees or shrubsPeat Bogs: poorly drained soil covered with moss ( like wet carpet)

Absorb large amounts of water, filter water.http://educationalminimovies.com/index.php/science/739/704-bill-nye-on-wetlands-part-1

marshswampPeat bogMarine BiomesEstuariesThe broadening at the mouth of a river that empties into the seaFresh water mixes with salt water typical species: oysters, spongesLarge amounts of sediment are deposited

sunMarine BiomesOceans and SeasHave a wide variety of living conditions, depending on depth:At the surface phytoplankton act as direct or indirect food for fish, jellyfish, crustaceans, mammals, birds.Ocean floor home of the benthos, the mollusks, crustaceans and bottom feeding fish which eat dead organisms on the ocean floor

>200m below surface not enough light for photosynthesis (no plants), but can still find species of fish, eels, squid and octopus

Marine BiomesCoral ReefsAre made of organisms called corals, which have a hard calcium carbonate based shellThe habitat supports huge amounts of biodiversity, offering food and shelter to numerous aquatic organisms

Coral

ZooxanthellaeZooxanthellae:Microscopic algae inside the cells of the coral animalSymbiosis: Zooxanthellae provide carbohydrates and oxygen for coral through photosynthesisCoral provides nutrients and habitat for zooxanthellae Coral Reefs

Threatened by global warming, pollution, overfishing

Change in water temperature may cause expulsion of zooxanthellea Sedimentation on top of corals prevents photosynthesis Factors affecting Aquatic BiomesSalinityTemperatureWater depthDirection and strength of currentTurbidity (water clarity)Solar energyNutrient availabilityPresence of oxygen and carbon dioxide