Biogeo lec 3 the physical setting

THE PHYSICAL THE PHYSICAL SETTINGSETTING

Amphibian Declines and Amphibian Declines and ClimateClimate Combination of factors have Combination of factors have

lead to amphibian decline lead to amphibian decline worldwideworldwide

2/3 of the 110 species of 2/3 of the 110 species of Harlequin frogs may have gone Harlequin frogs may have gone extinct in the last 25 yearsextinct in the last 25 years

Declines have occurred in Declines have occurred in pristine locations (cloud forests)pristine locations (cloud forests)

Global warming and fungus Global warming and fungus working in concertworking in concert

Chytrid Fungus grow and attack Chytrid Fungus grow and attack the skin of amphibiansthe skin of amphibians

Thicker cloud cover in the Thicker cloud cover in the tropics resulting from warmer tropics resulting from warmer temperatures allow for cooler temperatures allow for cooler ground temperatures in areas ground temperatures in areas allowing the fungus to growallowing the fungus to grow

Introduction:Introduction:

Limits to geographic ranges (most Limits to geographic ranges (most cases):cases):

Terrestrial habitatsTerrestrial habitats - climate and - climate and soil typessoil types

Aquatic habitatsAquatic habitats - temperature, - temperature, salinity, light and pressuresalinity, light and pressure

Heat EnergyHeat Energy

Two different sources of energy:

1. Heat stored in the Earth’s core (from the time the solar system was formed)

2. Radiant energy produced by the sun

Earth’s CoreEarth’s Core

1. Heat stored in the Earth’s core (from the time the solar system was formed)


1. Heat stored in the Earth’s core (from the time the solar system was formed) Radiates through the earth’s crust and

into space



into space moves and shapes earth crust forms mountains, causes earthquakes

and volcanic eruptions shifts plates containing continents



into space moves and shapes earth crust




and volcanic eruptions




and volcanic eruptions shifts plates containing continents

Mount St. HelensMount St. Helens

Mount St. HelensMount St. Helens

Solar RadiationSolar Radiation

2. Radiant energy produced by the sun


2. Radiant energy produced by the sun warms surface of land and water and

atmosphere just above



atmosphere just above differences in temperature and density

of air and water causes there movement




of air and water causes there movement both horizontally and vertically




of air and water causes there movement both horizontally and vertically causes wind patterns and ocean current




of air and water causes there movement both horizontally and vertically causes wind patterns and ocean current responsible for the Earth’s climate

Past TemperaturesPast Temperatures

Milankovitch Cycles influence global temperature on a long term basis –


A) Wobble changes on a 19,000-23,000 year cycle



B) Tilt changes by 3 degrees on a 41,000 year cycle



B) Tilt changes by 3 degrees on a 41,000 year cycle

C) Orbit cycles from circular to elliptical on a 100,000 year cycle

Laurentide Ice SheetLaurentide Ice Sheet Last Major Ice AgeLast Major Ice Age 18000 years ago18000 years ago Sequence of Sequence of

glacial recession glacial recession up to presentup to present

Great lakes left Great lakes left behindbehind

Repeated glacial Repeated glacial and interglacial and interglacial events have events have occurredoccurred

What causes What causes seasons?seasons?

Solar Energy and Temperature Regimes

Angle of incoming radiant energy affects the quantity of heat absorbed most intense when surface is perpendicular to incident solar radiation (2 reasons)



1) greatest amount of energy is delivered to smallest surface area



1) greatest amount of energy is delivered to smallest surface area

2) minimal amount of radiation is absorbed or reflected back into space during passage through the atmosphere because distance it travels through air is minimized

SeasonsSeasons

Earth is tilted 23.5o from vertical on its axis with respect to the sun

SeasonsSeasons


Solar radiation falls perpendicularly on different parts of the earth during an annual cycle

SeasonsSeasons



Differential heating creates the seasons

SeasonsSeasons



Differential heating creates the seasons Results in different daylengths of the

seasons

SeasonsSeasons



Differential heating creates the seasons Results in different daylengths of the seasons Equator is only location to experience 12

hours daylight / 12 hours darkness throughout the year

SeasonsSeasons

Summer solstice (June 22) sunlight falls directly on Tropic of

Cancer (23.5o N) and the Northern hemisphere is heated most intensely with longer days and shorter nights

experience summer while Southern hemisphere is in winter

SeasonsSeasons

Winter solstice (December 22) sunlight falls directly on Tropic of Capricorn (23.5o S) -> Southern hemisphere experiences summer and Northern hemisphere experiences winter

At the Arctic and Antarctic circle, 66.5o latitude -> one day each year of continuous daylight

Air Air CirculationCirculation

Solar radiation Solar radiation heats up surface heats up surface temperaturetemperature

Convective Hadley Convective Hadley cellscells

Wind patternsWind patterns Affect precipitation Affect precipitation

patternspatterns

Winds and Rainfall Wind patterns - Differential heating of earth’s

surface causes winds


surface causes winds Three convective “Hadley cells” in each

hemisphere



hemisphere Coriolis effect - winds are deflected east or

west (result from the rotation of the earth)




west (result from the rotation of the earth) Surface winds (influenced by the Coriolis effect)

initiate major ocean currents





initiate major ocean currents Currents are clockwise in the N.H. and

counterclockwise in S.H.





initiate major ocean currents Currents are clockwise in the N.H. and

counterclockwise in S.H. Warm currents on eastern continental margins;

cold currents on western continental margins

Surface Current PatternsSurface Current Patterns

Precipitation Patterns

Rainforests and cloud forests in tropics occur where cooling of ascending air laden with water vapor produces heavy rainfall at low and middle elevations


Rainforests and cloud forests in tropics occur where cooling of ascending air laden with water vapor produces heavy rainfall at low and middle elevations

Rainy seasons occur in the tropics when the sun is directly overhead and most intense heating occurs


Two belts of dry climates encircle the earth where cool dry air descends from the upper atmosphere (Horse latitudes between 30o and 40o both N and S)


Most of the world’s deserts lie in these two belts

1) the Mojave, Sonoran and Chihuahuan in N.A.

2) the Sahara in N. Africa and the Arid Zone in Australia

Mediterranean climates

Are also observed on the western sides of continents w/in these belts

Many of these deserts are not only on the western side of the continent but also on the eastern sides of major mountain ranges => Rain shadow effect

Rain ShadowRain Shadow

Small-scale and Temporal Variation

Same patterns just described on a global scale function on local scale.



Rain shadow effect on islands such as Puerto Rico



Rain shadow effect on islands such as Puerto Rico

Mountain tops having similar vegetation to more northern climates as in the Smokey Mountains of Tennessee more similar to boreal forests of northern Canada

Atacama DesertAtacama Desert

Driest place in the world

El Nino Southern Oscillation (5-7 year cycle) effects the worlds weather

patterns Normal conditions

result in cold water upwelling – high marine productivity

El Nino reverses currents and cold water upwelling does not occur – low marine productivity

Equatorial Countercurrent

Normally small Becomes much stronger in some years and

pushes warm water up the coasts of North and South America -> increases in rains on the western coasts as well as producing the only rains to occur in the Atacama Desert

Results in decreased upwelling in the Galapagos Islands where many marine organisms and seabirds suffer from lack of food

A) In Galapagos – marine animals such as marine iguanas and sea birds do well during normal years.

B) During El Nino events – land vertebrates (land iguanas and tortoises) do well due to increased precipitation which results in increased vegetation.

Cooling Effect of Elevation -Cooling Effect of Elevation -

Air expands as pressure of air Air expands as pressure of air decreases with increasing elevation decreases with increasing elevation --> results in heat loss as a result of --> results in heat loss as a result of molecules moving apart -molecules moving apart ->>Adiabatic coolingAdiabatic cooling --> also, less --> also, less dense air allows higher rate of heat dense air allows higher rate of heat loss resulting in colder airloss resulting in colder air

Soils:Soils:

Major Soil TypesMajor Soil Types - Four major - Four major processes that produce the primary processes that produce the primary soil typessoil types

1) 1) PodzolizationPodzolization - temperature - temperature deciduous and coniferous forestsdeciduous and coniferous forests

2) 2) LaterizationLaterization - tropical forests - tropical forests 3) 3) CalcificationCalcification - grasslands and - grasslands and

shrublandsshrublands 4) 4) Gleizaton Gleizaton - waterlogged tundra- waterlogged tundra

PodzolizationPodzolization

Podzolization Podzolization - temperate and subarctic - temperate and subarctic latitudes and at high elevationslatitudes and at high elevations

--> temperatures cool and precipitation --> temperatures cool and precipitation abundantabundant

--> organic material (humus) accumulates (low --> organic material (humus) accumulates (low temperatures inhibit microbial breakdown)temperatures inhibit microbial breakdown)

--> humus decays, organic acids leach through --> humus decays, organic acids leach through soilsoil

--> acidic soils in which coniferous forests --> acidic soils in which coniferous forests thrivethrive

Boreal ForestBoreal Forest

LateralizationLateralization

LateralizationLateralization - humid tropics - humid tropics --> high temperatures and heavy --> high temperatures and heavy

rainfallrainfall --> microbes and other organisms --> microbes and other organisms

break down dead organic material break down dead organic material quickly (little humus accumulates)quickly (little humus accumulates)

--> absence of organic acids--> absence of organic acids --> oxides of iron and aluminum --> oxides of iron and aluminum

precipitate to form red clay or a brick-precipitate to form red clay or a brick-like layer (laterite)like layer (laterite)

CalcareousCalcareous CalcareousCalcareous - arid and semi-arid environments - arid and semi-arid environments --> areas where thick layers of --> areas where thick layers of calcium calcium

carbonatecarbonate were deposited beneath ancient were deposited beneath ancient shallow tropical seasshallow tropical seas

--> rainfall relatively low--> rainfall relatively low --> evaporation and transpiration exceed --> evaporation and transpiration exceed

precipitationprecipitation --> cations not leached out--> cations not leached out --> rocklike layer of calcium carbonate => --> rocklike layer of calcium carbonate =>

CalicheCaliche --> where rainfall is heavier -> formation of deep --> where rainfall is heavier -> formation of deep

fertile soils =>fertile soils => tallgrass and shortgrass prairie tallgrass and shortgrass prairie habitathabitat

GleizationGleization Gleization Gleization - cold, wet polar regions- cold, wet polar regions --> typical process of soil formation--> typical process of soil formation --> permanently wet or frozen--> permanently wet or frozen --> low temperatures and waterlogged --> low temperatures and waterlogged

conditions prevent decompositionconditions prevent decomposition --> acidic organic matter builds--> acidic organic matter builds --> may form a layer of peat that can be --> may form a layer of peat that can be

several meters thickseveral meters thick --> inorganic layer of grayish clay beneath--> inorganic layer of grayish clay beneath --> support a sparse vegetation of acid---> support a sparse vegetation of acid-

tolerant speciestolerant species

Major Soil TypesMajor Soil Types

Soil Types and ClimateSoil Types and Climate

Soil and TopographySoil and Topography

MicroenvironmentMicroenvironment

Gopher Tortoise BurrowsGopher Tortoise Burrows

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BURROW SUN

Technology

Biogeo lec 3 the physical setting