APES // Chapter 4: Global Climates & Biomes

Terrestrial Biome

Geographic region categorized by their average temperature, precipitation, & plant growth forms.

Aquatic Biome

An aquatic region categorized by the combintion of salinity, depth, & water flow.

Habitat

Tundra

• Cold & treeless, but low-growing vegetation

• Frozen soil in winter

• Short growing season (4 months)

• Contains permafrost

Permafrost

Impermeable & permanently frozen layer of soil found in the tundra

Boreal Forest/Coniferous Forest/Taiga

• Coniferous evergreen trees

• Cold winters & short growing seasons

• 50-60 Degrees N (Europe Russia N. America)

• Nutrient-poor soil from low decomposition

Temperate Rainforest

• Oceans currents create moderate temperatures

• High precipitation

• Found in W. coasts of N. America, S. Chilie, W of New Zealand, Tasmania islands

• 12 month growing season

• Supports very large trees

Temperate Seasonal Forest

• Warm summers & cold winters

• 1m (39inches) of rain per year

• Found in E. US, Japan, China, Europe, Chile, E. Australia

• Broadleaf deciduous trees (beech, maple, oak, hickory)

• More nutritious soil from more decomposition

Woodland/Shrubland

• Hot dry summers, mild rainy winters

• S. of Cali/Australia/Africa & Mediterranean Sea

• 12 month growing season, but constrained by low precipitation & low temperatures

• Wildfires are common & plants are well adapted

Temperate Grassland/Cold Desert

• Cold harsh winters, hot dry summers

• Lowest amount of rain in all the temperate biomes

• Great Plains in N. America, S. America, centeral Asia, E. Europe

• Plant growth restricted by not enough rain in summers & too cold in winter

• Grasses & flowers, nonwoody plants with frequent grazing

Tropical Rainforest

• A warm & wet, found between 20 N & 20 S of equator

• Average temperature >20 C

• C. & S. America, Africa, S.E. Asia, N.E. Australia

• Very little temperature variation

• Most biodiversity per hectare per terrestrial biome (2/3 of land species)

Tropical Seasonal Forest/Savana

• Warm temperatures, wet & dry seasons

• C. America, Atlantic coast of S. America, S. Asia, N.W. Australia, sub-Saharan Africa

• Pretty fertile soil from high decomposition rates

• Plants are restricted by low precipitation

• Grasses & scattered deciduous trees

Subtropical Desert

• 30 N & S, hot & very dry condition, very little vegetation

• Mojave Desert (S.W. US), Sahara Africa, Arabian (Middle East), Great Victoria (Australia)

• Cacti, euphorbs, & succulents are well adapted

Polar Desert/Ice Cap

Littoral Zone

Shallow zone of soil & water where there are emergent plants & algae for lakes/ponds

Limnetic Zone

Open water of lakes & ponds, most phytoplankton are here

Phytoplankton

Floating algae

Profundal Zone

Zone of water in deeper lakes where there’s no sunlight & below the Limnetic zone

Benthic Zone

Muddy bottom of lakes, ponds, and oceans

Streams & Rivers

• Flowing fresh water from underground springs/runnoff from rain/snow

• Streams are narrow & carry less water than rivers

Lakes & Ponds

• Standing water, and lakes are larger than ponds

• Some waters are too deep to support emergent vegetation

• Contains different zones

Oligotrophic

Lake with low level of productivity, low level of N & P

Mesotropic

Lake with moderate level of productivity, moderate level of N & P

Eutrophic

Lake with high level of productivity, high amounts of N & P

Freshwater Wetland

• Submerged/saturated by water for at least part of the year

• Shallow enough for emergent vegetation

• Very very productive

Salt Marsh

• High in salinity

• No woody emergent vegetation

• Coast of temperate climates

• Very very productive

Estuary

Mangrove Swamp

• Coast of tropical & subtropical biomes

• Salt tolerant trees & submerged roots

• Mangrooves help protect from erosion & storm damage

Intertidal Zone

• Narrow band between high & low tide

• Waves crash onto the shore, challenging for organism to hold on and not get washed aw

Coral Reef

• Most diverse marine biome

• Warm shallow waters beyong the shoreline

• Most diverse corals reefs are found in waters with poor nutrients & food

Coral Bleaching

• Algae inside corals die, causing corals to turn white

Open Ocean

• Deep ocean water

• Far from shoreline

• No sunlight at the bottom

• Separated into different zones

Photic Zone

Upper layer where photosynthesis is possible from amount of sunlight

Aphotic Zone

Deeper layer of ocean where there’s not enough sunlight for photosynthesis

Chemosynthesis

Some bacteria in the oceans use this to generate energy with methane & hydrogen sulfide

Salinity

• Total amount of material dissolved in water (mostly constant)

• 3.5% salinity in sea water

• Increased by evaporation & sea ice formation

• Decreased by precipitation, runoff from land, & melting sea ice

Why does this happen?

• High amount of solar radiation at equator (high temperature)

• High amounts of precipitation at equator (low salinity)

• High amounts of evaporation at 30 N & S (high salinity)

Ocean Density

Higher temperature —> Lower density

Higher salinity —> Higher Density

Thermocline

• Layer of ocean with rapid change in temperature with depth

• Creates a vertical barrier for many marine life,

• Strong in low latitudes, nonexistent in high

Pycnocline

• Layer of ocean with rapid change in density with depth

• Strong in low latitudes, nonexistent in high

3 layered zones in the ocean according to density

Shallow Surface/Mixed zone —> 2%

Transition Zone —> 18%

Deep Zone —> 80% (only thing found in high latitudes because of constant temperature & density)

Surface Currents

• Move warm & cold water around the plant & impact global climate & productivity

• Driven by temperature, gravity, wind, Coriolis, continent locations

• Surface Waters + Winds + Coriolis = Direction if flows in

• (Tropical is 8 cm higher than mid-latitude because of a slight slope that causes water to flow away from the equator)

Gyres

• North Pacific (clockwise)

• South Pacific (counter-clockwise)

• North Atlantic (clockwise)

• South Atlantic (counter-clockwise)

• Indian (counter-clockwise)

Upwelling

Rising cold water that’s nearing the shore with lots of nutrients from sunken & decomposed organic matter, creates fertile ocean waters with lots of phytoplankton.

Global Conveyor Belt/Thermohaline Circulation

• Moves heat & nutrients around the globe

• Mixes water across the globe

• driven by weird high salinity surface waters at 30 N

• Takes hundreds of years to circulate fully

• Could be negatively affected by climate change

How could climate change possibly affect thermohaline circulation

Water atmosphere —> increase ice melt —> decrease salinity & density —> less sinking/potential shutdown of the circulation —> no more warm water in western Europe, where climates would be cool

El Nino-Southern Oscillation

• Periodic reversal of water/wind currents in the equatorial Pacific

• Results from unstable interaction of ocean surface & atmosphere

• Creates worldwide effects on weather

• Fluctuations of temperatures between ocean & atmosphere in Equatorial Pacific Ocean

• El Nino —> Periodic warming

  • Trade winds weaken/reverse

  • Upwelling on S. America weakens (bad for commercial fishing)

• El Nina —> Periodic cooling

  • Trade winds strengthen and more warm water eastwards

  • Upweling in S. America increases

  • More Hurricanes in the Gulf/Atlantic Ocean

• Happened for the last 125k years

El Nino Conditions in N. America

• Warmer in N.W.

• Dryer in E.

• Wetter in extended Pacific Jet Stream (south)

La Nina Conditions in N. America

• Cooler above variable Polar Jet stream (N.)

• Wetter below variable Polar Jet stream (N.W.)

• Warmer below S.E.

• Dryer in S.

Saturation Point

Maximum water vapor capacity of the air, warmer air can hold more

Adiabatic Cooling

Warm air rises —> Pressure decreases —> Cooler air —> Cool air falls

Adiabatic Heating

Cool air falls —> Pressure increase —> warmer air —> warm air rises

Latent Heat Release

Heat exchanged in a phase change (cooling from when water vapor turns into liquid water, because latent heat was released)

Atmospheric Convection Current

Hadley Cell

• Two cells between 0 & 30 N and 0 & 30 S

• Equator has warm air rising, then cool air sinks at 30 N & S

• Contains ITCZ

  • Band of rain clouds that encircles Earth near equator due to Convergence of air from two cells

Intertropical Convergence Zone (ITCZ)

A moving band of rain clouds that encircles Earth near the equator due to Convergence of air from the Hadley Cells

Polar Cell

Between the poles at 60 N & S

Ferrell Cell

Between 60 N & 30 N and 60 S & 30

Coriolis Effect

• Earth rotates creating more than 2 convection cells

• Wind flows due to differences in horizontal pressure (always from high to low)

• Clockwise in the northern hemisphere & counter-clockwise in the southern hemisphere

• Rate of rotation is fastest at the equator because of largest circumference

• Effect is strongest at the poles & weakens near the equators

Rain Shadow

• Rain/Snow in the windward slop of the mountain towards the sea

• Wind goes up the mountain, pressure decreases, adiobitc cooling and the moisture condenses & rains

• dry slope on the other side because of the rain shadow

Low Pressure System

• Decreasing pressure approaching center

• counter-clockwise

• inwards

• air rises

• decreasing temperature

• Condensation & cloud flormation

• cloudy skies (rainy weather)

High Pressure Systems

• Pressure increases as you approuce the center

• clockwise (opposite in the southern hemisphere)

• outwards

• sinking

• warmer air

• clear skies

• evaporation & cloud dissipation