Major Ecosystems/Biomes of the Major Ecosystems/Biomes of the WorldWorld

Earth’s Major BiomesEarth’s Major Biomes

o BiomeBiome• A large, relatively distinct terrestrial region with a A large, relatively distinct terrestrial region with a

similar climate soil, plants, and animals, regardless similar climate soil, plants, and animals, regardless of where it occurs in the worldof where it occurs in the world

• Nine major biomes Nine major biomes

o Location of each biome is Location of each biome is primarily determined by:primarily determined by:• Temperature (varies with both latitude and Temperature (varies with both latitude and

elevation)elevation)• PrecipitationPrecipitation

o Biomes can also be defined byBiomes can also be defined by• Winds, rapid temperature changes, fires, floods, Winds, rapid temperature changes, fires, floods,

etc.etc.

Vertical ZonationVertical Zonation

o Increasing Increasing in elevation in elevation has similar has similar effect on effect on

ecosystem ecosystem as traveling as traveling

to higher to higher latitudeslatitudes

Tropical RainforestTropical Rainforesto Lush, species-rich Lush, species-rich

biome that occurs biome that occurs where climate is where climate is warm and moist warm and moist throughout the yearthroughout the year

o PrecipitationPrecipitation• 200-450 cm/yr200-450 cm/yr

o Very productive Very productive biomebiome

o Most species-rich Most species-rich biomebiome

Tropical RainforestTropical Rainforesto Ancient, weathered, Ancient, weathered,

nutrient-poor soilnutrient-poor soil• Nutrients tied up in Nutrients tied up in

vegetation, not soilvegetation, not soil

o VegetationVegetation• 3 distinct canopy 3 distinct canopy

layerslayers

o AnimalsAnimals• Most abundant insect, Most abundant insect,

reptiles and reptiles and amphibians on earthamphibians on earth

DesertsDesertso Biome where lack of Biome where lack of

precipitation limits precipitation limits plant growthplant growth

o TemperatureTemperature• Can very greatly in Can very greatly in

24-hr period, as well 24-hr period, as well as yearly (based on as yearly (based on location)location)

o PrecipitationPrecipitation• < 25 cm/yr< 25 cm/yr

DesertsDesertso Soils low in nutrients, high in saltsSoils low in nutrients, high in saltso Vegetation sparseVegetation sparse

• cactus and sagebrushcactus and sagebrusho Animals are very small to regulate Animals are very small to regulate

temperaturetemperatureSonoran Desert

Temperature Temperature Deciduous ForestsDeciduous Forests

o Forest biome that occurs Forest biome that occurs in temperate areas with in temperate areas with a moderate amount of a moderate amount of precipitationprecipitation

o PrecipitationPrecipitation• 75-150 cm/yr75-150 cm/yr

o TemperatureTemperature• SeasonalitySeasonality• Hot summers and cold Hot summers and cold

winterswinters

Temperate Deciduous Temperate Deciduous ForestForest

o Topsoil is rich in organic material and Topsoil is rich in organic material and underlain by clayunderlain by clay

o Vegetation is primarily Vegetation is primarily deciduousdeciduous• Oak, maple, beechOak, maple, beech

o AnimalsAnimals• Deer, bear and small animalsDeer, bear and small animals

o Most of this biome land area Most of this biome land area has been regenerated after has been regenerated after farming & timber harvestfarming & timber harvest

GrasslandGrasslando Grasslands with hot Grasslands with hot

summers, cold winters and summers, cold winters and too little precipitation to too little precipitation to support treessupport trees

o PrecipitationPrecipitation• 25-75 cm/yr25-75 cm/yr

o Tall grass prairiesTall grass prairieso Short grass prairiesShort grass prairieso 90% of this biome has 90% of this biome has

been lost to farmlandbeen lost to farmland

GrasslandGrasslando Soil has thick, organic materialSoil has thick, organic material

rich organic horizon.rich organic horizon.o Periodic fires keep the dominant Periodic fires keep the dominant

vegetationvegetation grassesgrasseso AnimalsAnimals

• Once covered with Once covered with bison- no longer truebison- no longer true

• Smaller animals are Smaller animals are still present (ex: still present (ex: prairie dogs)prairie dogs)

ChaparralChaparralo Also called a Also called a

Mediterranean Mediterranean ClimateClimate• Ex: Southern Ex: Southern

CaliforniaCalifornia• Ex: GreeceEx: Greece

o TemperatureTemperature• Mild, moist wintersMild, moist winters• Hot, dry summersHot, dry summers

o Frequent firesFrequent fires

ChaparralChaparralo Soil is thin and often Soil is thin and often

not fertilenot fertileo VegetationVegetation

• Dense growth of Dense growth of evergreen shrubsevergreen shrubs

• Lush during the Lush during the growing seasongrowing season

o AnimalsAnimals• Mule deer, Mule deer,

chipmunks, many chipmunks, many species of birdsspecies of birds

SavannaSavannao Tropical grassland Tropical grassland

with widely scattered with widely scattered treestrees

o TemperatureTemperature• Varies little throughout Varies little throughout

the yearthe year

o PrecipitationPrecipitation• Seasons regulated by Seasons regulated by

precipitation, not precipitation, not temperaturetemperature

• 76-150 cm/yr76-150 cm/yr

SavannaSavannao Soil low in nutrients due to leachingSoil low in nutrients due to leachingo VegetationVegetation

• Wide expanses of grassWide expanses of grass• Occasional Acacia treesOccasional Acacia trees

• Have fire adaptive Have fire adaptive characteristicscharacteristics

o AnimalsAnimals• Herds of hoofed Herds of hoofed

animalsanimals• Large predators- Large predators-

lions, hyenas, etc.lions, hyenas, etc.

Temperate Temperate RainforestRainforest

o Coniferous biome with cool weather, Coniferous biome with cool weather, dense fog and high precipitationdense fog and high precipitation• Ex: Northwest USEx: Northwest US

o PrecipitationPrecipitation• > 127 cm/yr> 127 cm/yr• Heaviest in winterHeaviest in winter

o TemperatureTemperature• Winters are mildWinters are mild• Summers are coolSummers are cool

Temperate Temperate RainforestRainforest

o Soils are nutrient-poor, but high in organic Soils are nutrient-poor, but high in organic material (dropped needles)material (dropped needles)• Cool temperatures slow decompositionCool temperatures slow decomposition

o Dominant VegetationDominant Vegetation• Large evergreen treesLarge evergreen trees• Old-growth forestOld-growth forest

o Variety of cool Variety of cool climate animal lifeclimate animal lifeo Very high speciesVery high species richnessrichnesso Heavily loggedHeavily logged

Boreal ForestsBoreal Forests

o A region of coniferous forests in the A region of coniferous forests in the northern hemispherenorthern hemisphere• Just south of tundraJust south of tundra

o Covers 11% of earth’s Covers 11% of earth’s landlando Growing SeasonGrowing Season

• A little longer than A little longer than tundratundra

o PrecipitationPrecipitation• ~ 50 cm/yr~ 50 cm/yr

Boreal ForestsBoreal Forestso Soils are acidic and mineral poorSoils are acidic and mineral pooro Vegetation comprised of drought Vegetation comprised of drought

resistant conifersresistant conifers• White spruceWhite spruce• Balsam firBalsam fir• Eastern larchEastern larch

o Mostly small Mostly small animals and animals and migrating birdsmigrating birds

o Some large animals Some large animals are presentare present• Wolves, bear, mooseWolves, bear, moose

TundraTundrao Treeless biome in the far north with Treeless biome in the far north with

harsh, cold winters and extremely harsh, cold winters and extremely short summersshort summers

o PrecipitationPrecipitation• 10-25 cm/yr10-25 cm/yr

o TemperatureTemperature• Short growing seasonShort growing season• 50-160 days50-160 days

TundraTundrao Nutrient poor soils with little organic Nutrient poor soils with little organic

materialmaterial• Permafrost presentPermafrost presento Low species richnessLow species richness• Veg is mostly grasses Veg is mostly grasses

and sedgesand sedges• Very simple food webVery simple food web

o Low primary Low primary productivityproductivity

Aquatic EcosystemAquatic Ecosystemo Fundamental DivisionFundamental Division

• FreshwaterFreshwater• SaltwaterSaltwater

o Aquatic Ecosystems also affected byAquatic Ecosystems also affected by• Dissolved oxygen level, light penetration, Dissolved oxygen level, light penetration,

pH, presence/absence of currentspH, presence/absence of currentso Three main ecological categories of Three main ecological categories of

organismsorganisms• Plankton- free floatingPlankton- free floating• Nekton- strong swimmingNekton- strong swimming• Benthos- bottom dwellingBenthos- bottom dwelling

Freshwater Freshwater EcosystemsEcosystems

o Includes:Includes:• Rivers and streamsRivers and streams• Lakes and pondsLakes and ponds• Marshes and swampsMarshes and swamps

o Represent 2% of earth’s surfaceRepresent 2% of earth’s surfaceo Assist in recycling water back to the Assist in recycling water back to the

oceans (Biogeochemical Cycling)oceans (Biogeochemical Cycling)

Rivers and StreamsRivers and Streamso Changes greatly Changes greatly

from headwater to from headwater to mouthmouth

o HeadwatersHeadwaters• Shallow, cool, Shallow, cool,

swiftly flowing, high swiftly flowing, high oxygenatedoxygenated

o MouthMouth• Not as cool, slower Not as cool, slower

flowing, less oxygen flowing, less oxygen in waterin water

Lakes and PondsLakes and Ponds

o Body of freshwater that does not flowBody of freshwater that does not flowo Three zonesThree zones

• LittoralLittoral• LimneticLimnetic• ProfundalProfundal

o Experience thermal stratification Experience thermal stratification (depending on depth)(depending on depth)

Lakes and PondsLakes and Pondso Littoral ZoneLittoral Zone - shallow water area - shallow water area

along the shorealong the shoreo Limnetic ZoneLimnetic Zone - open water beyond - open water beyond

the littoral zonethe littoral zoneo Profundal ZoneProfundal Zone - beneath the limnetic - beneath the limnetic

zone of deep lakeszone of deep lakes

Thermal StratificationThermal Stratification

o Temperature Temperature changes sharply changes sharply with depthwith depth

o ThermoclineThermocline• Temperature Temperature

transition between transition between warmer surface warmer surface water and colder water and colder water at depthwater at depth

• Only present in Only present in warm monthswarm months

Marshes and SwampsMarshes and Swampso Lands that shallow, fresh water covers Lands that shallow, fresh water covers

for at least part of the yearfor at least part of the year• Characteristic soil- water logged and Characteristic soil- water logged and

anaerobic for periods of timeanaerobic for periods of time• Water tolerant vegetationWater tolerant vegetation

o Were once regularly Were once regularly filled infilled in• More recently their More recently their

ecosystem services have ecosystem services have been better recognizedbeen better recognized

• Flood protection, waterFlood protection, water

filtering, filtering, etc.etc.

EstuariesEstuarieso Where freshwater and saltwater mixWhere freshwater and saltwater mixo Highly variable environmentHighly variable environment

• Temperature, salinity, depth of light Temperature, salinity, depth of light penetrationpenetrationo Highly productiveHighly productive

• Nutrients transported from Nutrients transported from landland

• Tidal action promotes rapid Tidal action promotes rapid circulation of nutrientscirculation of nutrients

• High level of light High level of light penetrates shallow waterpenetrates shallow water

EstuariesEstuaries

Marine EcosystemsMarine Ecosystemso Subdivided Subdivided

into life zonesinto life zones• Intertidal zoneIntertidal zone• Benthic zoneBenthic zone• Pelagic Pelagic

environmentenvironment• Neritic Neritic

ProvinceProvince• Oceanic Oceanic

ProvinceProvince

Intertidal ZoneIntertidal Zoneo Area of shoreline between low and high Area of shoreline between low and high

tidestideso HabitatHabitat• Sandy or rockySandy or rocky

o MusclesMuscleso CrabsCrabso AlgaeAlgaeo OystersOysterso BarnaclesBarnacleso Animals must Animals must

adapts to adapts to changing changing conditionsconditions

Benthic ZoneBenthic Zone

o Ocean floor, extending from tidal zone Ocean floor, extending from tidal zone to deep sea trenchesto deep sea trenches

o Sediment is mostly mudSediment is mostly mud• Burrowing worms and clamsBurrowing worms and clams

o Three zoneThree zone• Bathyal: 200m - 4000m deepBathyal: 200m - 4000m deep• Abyssal: 4000m -6000m deepAbyssal: 4000m -6000m deep• Hadal: 6000m – bottom of deep sea Hadal: 6000m – bottom of deep sea

trenchestrenches

Productive Benthic Productive Benthic CommunitiesCommunities

o Seagrass BedsSeagrass Beds• Present to depth of 10 mPresent to depth of 10 m• Provide food and habitat toProvide food and habitat to

ecosystemecosystem

o Kelp ForestKelp Forest• 60-m long brown algae found off rocky shores60-m long brown algae found off rocky shores• Diversity of life supported by kelp rivals coral reefsDiversity of life supported by kelp rivals coral reefs

o Coral ReefsCoral Reefs• Built from accumulated layers of CaCOBuilt from accumulated layers of CaCO33

• Colonies of millions of tiny coral animalsColonies of millions of tiny coral animals• Found in shallow warm waterFound in shallow warm water• Most diverse of all marine environmentsMost diverse of all marine environments

Productive Benthic Productive Benthic CommunitiesCommunities

Left: Seagrass BedLeft: Seagrass Bed

Right: Kelp ForestRight: Kelp Forest

Human DisturbanceHuman Disturbance

Human Impact on Coral ReefsHuman Impact on Coral Reefs

o SedimentationSedimentation• From clear-From clear-

cutting cutting upstreamupstream

o OverfishingOverfishingo Coral bleachingCoral bleachingo Mining of corals Mining of corals

as building as building materialsmaterials

o Runoff pollutionRunoff pollution

Pelagic EnvironmentPelagic Environment

o All the open ocean waterAll the open ocean watero Two main divisionsTwo main divisions

• Neritic ProvinceNeritic Province• Water that overlies the continental shelf (to Water that overlies the continental shelf (to

depth of 200 m)depth of 200 m)• Organisms are all floaters or swimmersOrganisms are all floaters or swimmers

• Oceanic ProvinceOceanic Province• Water that overlies depths greater than 200 mWater that overlies depths greater than 200 m• 75% of world’s ocean75% of world’s ocean• Most organisms are dependent on marine snowMost organisms are dependent on marine snow• Organisms are filter feeders, scavengers and Organisms are filter feeders, scavengers and

predatorspredators

Human Impacts on the OceanHuman Impacts on the Ocean