Download Biomes - Science

Environmental Science
2012
Source: University of California Museum of Paleontology
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Deserts cover about one fifth of the Earth’s
surface
Rainfall is less than 50cm/year
Most deserts occur at low latitudes
Soils often have abundant nutrients because
they need only water to become very
productive and have little or no organic
matter
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Disturbances are common
 Fires, cold weather, sudden infrequent flooding
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Few large mammals due to incapable of
storing sufficient water and withstanding
heat
 Dominant animals are reptiles
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Four types: hot and arid, semiarid, coastal,
cold
Sand dunes in Death Valley National
Monument, California.
Horned Viper Egypt
Castle Valley, Utah, east
of Arches National Park.
From left: Baja, Mexico desert; desert in Uluru National Park, Australia; desert near the Kofa
Mountains, Arizona.
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Coldest of all of the biomes
Tundra means treeless plain
Two types of tundra:
 Arctic tundra: located in northern hemisphere
 Alpine tundra: located on mountains throughout
the world at high altitudes where trees cannot
grow
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Characterized by:
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Frost-molded landscapes
Extremely low temperatures
Little precipitation
Poor nutrients
Short growing season and reproductive season
Low biotic diversity
Limitation of drainage- boggy
Energy and nutrients in the form of dead organic
matter
From left: alpine tundra in Mt. Rainier National Park,
Washington; Dall Sheep in the Arctic National Wildlife
Tundra along the Colville River, Alaska. Refuge, Alaska.
From left: tundra near Churchill, Manitoba, Canada; tundra in the
Arctic National Wildlife Refuge, Alaska.
Pica: native to alpine
tundra
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Characterized as lands dominated by grasses
rather than large shrubs or trees
Hotter and dryer climates
Two main divisions:
 Temperate grasslands
 Savannas
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Fires are important in maintaining grasslands
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Savannas are grasslands scattered with
individual trees
Cover almost half the surface of Africa
Also located in Australia, South America, and
India
Found in warm or hot climates where annual
rainfall is from 50.8 to 127cm per year
Rainfall is concentrated in six or eight months
of the year, followed by a long period of
drought
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Temperate grasslands have grasses as their dominant
vegetation, trees and large shrubs are absent
Temperatures vary from summer to winter
Rainfall is less in temperate grasslands than savannas
Major temperate grassland regions:
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Veldts- South Africa
Puszta- Hungary
Pampas- Argentina
Steppes- former Soviet Union
Plains and prairies- central North America
A grassland west of Coalinga, California.
Savanna in the Samburu Game Preserve,
Kenya.
Zebra and
Wildebeest
African savanna.
Russian steppes.
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Can consist of several different types of
terrain: flat plains, hills, mountain terrain
Created when cool water from an ocean
merges with a landmass that is at a high
temperature
Found at about 30 to 40 degrees below and
above the equator
Major chaparral biomes found:
 Coast of Baja and California
 Areas around Mediterranean Sea
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Characteristics:
 Wet winter
 Dry summer
 Periods of droughts and fire
 Temperature is about 30 degrees F in the winter
and up to 100 degrees F in summer
 10 – 17 inches of rainfall annually
Chaparral California.
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Forests occupy one-third of Earth’s land area
Forests account for two-thirds of the leaf area
of land plants
Contain about 70% of carbon present in living
things
Forests are dominated by trees and other
woody vegetation:
 Rainforests
 Deciduous (aka temperate)
 Coniferous (aka boreal or taiga)
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Deciduous: trees that have broad leaves that
are lost annually
Occur in eastern North America, northeastern
Asia, and western and central Europe
Well defined seasons with a distinct winter
Moderate climate and growing season
Left: Wisconsin
woods. Right: The
forested hills of the
Adirondacks, New
York.
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Temp. -30*C – 30*C
Precipitation 75-100cm distributed evenly
throughout the year
Soil is fertile with decaying litter
Canopy is moderate to dense and allows light
to penetrate, allowing well developed
understory
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Coniferous: evergreen trees, with needle like
leaves, do not shed leaves
Represent the largest terrestrial biome
Between 50 and 60 degrees north latitudes
Found in broad belt of Eurasia and North
America: two-thirds in Siberia, with the rest
in Scandinavia, Alaska, and Canada
Seasons are divided into short, moist, and
moderately warm summers and long, cold,
and dry winters
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Low temps.
Precipitation mainly in form of snow, 40100cm annually
Soil is thin, nutrient-poor and acidic
Canopy permits low light penetration,
understory is limited
From left: taiga in Jasper
National Park, Alberta,
Canada; forest west of
Stockholm, Sweden.
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Occur near the equation, within the area
bounded by latitudes 23.5 degrees N and 23.5
degrees S
More than one half of rainforests have
already been destroyed
From left: Olympic Peninsula rain forest, Washington; Patria River, Costa Rica;
Ranomafana National Park, Madagascar; Hawaiian forest.
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Characteristics:
 Great diversity of species
 Winter is absent, two seasons (rainy and dry)
 Length of daylight is 12 h and varies little
 Temperature 20-25* C
 Precipitation is evenly distributed throughout the
year, over 2000mm annually
 Soil is nutrient poor and acidic
 Canopy is layered, little light penetration
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Freshwater is defined as having a low salt
concentration (less than 1%)
3 different types:
 Ponds and lakes
 Streams and rivers
 Wetlands
A lake at Acadia National Park, Maine.
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Scattered throughout the Earth
Many ponds are seasonal, lakes can exist for
hundreds of years or more
Temperatures vary
 Summers: 4*C near bottom, 22*C at tope
 Winter: 4*C near bottom, 0*C at top (with ice)
 Spring and fall: there is a mixing of the layers
From left: a view across
Manzanita Lake toward Mt.
Lassen, California; a forest pond
near Donnelly, Idaho; a Great
Blue Heron; Paranagat Lake,
southeastern Nevada.
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Littoral zone: topmost zone near the shore
 Warmest, shallow
 Diverse community
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Limnetic zone: near-surface open water
surrounded by the littoral zone
 Well-lighted
 Freshwater fish dominate
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Profundal zone:
 Deep-water part of lake
 Colder and denser, with little light
Littoral Zone
Profundal Zone
Limnetic Zone
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Bodies of flowing water moving in one
direction
Can be found anywhere
Get their starts at headwaters, which may be
springs, snowmelt or lakes, and travel all the
way to their mouths, usually another water
channel or ocean
Temperature is cooler, clearer, and higher
oxygen levels at the source than the mouth
From left: McArthur-Burney Falls State Park, California; trout; Green River, Utah; Brooks
River, Alaska.
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Areas of standing water, support aquatic
plants, include marshes, swamps, and bogs
Moist and humid conditions
Highest species diversity of all ecosystems
Not all wetlands are freshwater, some have
high salt concentrations such as salt marshes
From left: Pescadero Marsh, California; coastal marsh at Umpqua Dunes, Oregon; trees
and bogs on Esther Island, Alaska.
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Marine regions cover about three-fourths of
the Earth’s surface
Include ocean’s, coral reefs, and estuaries
Marine algae supply much of the world’s
oxygen supply and take in a huge amount of
atmospheric carbon dioxide
Reef fish and coral off Eniwetok atoll in the
central Pacific.
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Largest of all ecosystems
Ocean zones:
 Intertidal- where ocean meets land, sometimes
exposed
 Pelagic- water further from the land, open ocean
 Benthic- area below pelagic, temperatures and
light decreases
 Abyssal- deep ocean, very cold water, highly
pressured, high in oxygen, low in nutrients
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Widely distributed in warm shallow waters
From left: reef life in
Found as barriers along continents,
the Gulf of Aqaba,
Red Sea; a reef at
fringing islands, and atolls
Fanning Island atoll
Waters are nutritionally poor, obtain in the central
Pacific; a reef in the
nutrients from algae and plankton
Florida Keys
National Marine
Diverse in species
Sanctuary.
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Areas where freshwater streams or rivers
merge with the ocean
The mixing of waters with such different salt
concentrates creates a very interesting and
unique ecosystem
Support diverse species
From left: Mangrove roots, south Florida; wetlands and tidal streams in the Ashe Island
area, ACE Basin National Estuarine Research Reserve, South Carolina; a salt marsh in
Winyah Bay National Estuarine Research Reserve, South Carolina.
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https://www.youtube.com/watch?v=ZouWW
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