Figure 28.2 Krogh 2000

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Figure 28.2 (Krogh 2000)
2
Basic units of life

• Population all members of a single species that
  live together in a defined area
• Community populations of all different species
  that live and interact together in a defined area
• Ecosystem the living (biotic) community and the
  non-living (abiotic) elements it interacts with
• Biosphere interactive collection of the Earths
  ecosystems

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Biomes

• Vegetation of the Earth divided into distinct
  blocks or biomes based on mean annual
  precipitation and mean annual precipitation.
• Biomes represent the major ecosystems of the
  world.
• Biomes consist of distinct combinations of plant
  and animal species and are characterized by an
  approximately uniform form of vegetation such as
  grassland or forest.

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Biomes

• Tundra
• Taiga (boreal forest)
• Temperate deciduous forest
• Tropical rainforest
• Temperate grassland
• Desert
• Savanna
• Chaparral
• Aquatic (marine and freshwater)

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30
25
Savanna
Tropical Rainforest
20
Temperate Forest
15
Desert
Chaparral
Grassland
10
5
Mean annual temperature (oC)
0
Taiga
-5
-10
Tundra
-15
50
100
200
300
400
Mean annual precipitation (cm)
6
Figure 29.20 (Krogh 2000)
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Figure 29.24 (Krogh 2000)
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Criteria for Detailed Examination of Biomes

• Primary Region
• Climate and Soils
• Vegetation and/or Animals
• Environmental Concerns

9
Fig. 50.19, p. 911
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Tundra

• The word tundra comes from the Finnish word
  tunturia which means treeless plain.
• The tundra is a largely inaccessible, barren,
  treeless part of the world, but occupies almost
  25 of the Earths land surface.

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Tundra Primary Region

• Arctic tundra occupies a circumpolar band
  between the Artic Ocean and the polar caps to the
  north and the coniferous forest boundary to the
  south

• Alpine tundra smaller, but similar region found
  above the tree-line of high mountains. The
  alpine tundra is an example of how mountains can
  be an exception to strict biome boundaries.

12
Figure 29.24 (Krogh 2000)
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Tundra Climate and Soils

• Mean annual temperature below that required for
  plant growth for much of the year
• Mean winter temperature of -34oC (-30oF)
• Very short growing season (50 days) with mean
  summer temperature of between 3-12oC (37-54oF).
• Mean annual precipitation less than 25cm mostly
  in the form of snow and spring rain

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Tundra Climate and Soils (cont)

• Even with low precipitation the tundra is marshy
  and covered with numerous small lakes in the
  summer.
• Why?
• Permafrost layer of soil beneath the surface at
  a 1 meter depth which is permanently frozen
  water and plant roots cannot penetrate this layer
  therefore summer rains pool at the surface of
  tundra

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Tundra Climate and Soils (cont)

• Low productivity accumulation of energy or
  biomass
• Low microbial activity (activity of bacteria and
  fungi) due to low temperatures

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Tundra Vegetation and Animals

• Vegetation low shrubs, mosses, lichens,
  grasses, and sedges
• Animals summer migrants such as many birds
  (geese, ducks, sandpipers) and permanent
  residents including reindeer, caribou, musk oxen,
  bear, artic fox, lemmings, lynx, snow hairs, and
  some birds (snowy owl and ptarmigan)

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Tundra Environmental Concerns

• Vegetation slow to recover from disturbance given
  low temperatures and short growing seasons.
• Degradation (break-down) of pollutants would be
  very slow given low microbial activity.
• 1Development and the opening of the tundra for
  2oil exploration therefore subjects of main
  concern.

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Taiga (Boreal Forest)

• The boreal forest includes the large expanse of
  coniferous forest (evergreen trees with needle or
  scale-like leaves) that juts up against the
  tundra.
• Found only in the Northern hemisphere, as there
  is no land in these extreme latitudes in the
  Southern hemisphere.
• Conditions similar to but less severe than the
  tundra.

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Fig. 50.18, p. 910
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Taiga Primary Region

• 50-60o North latitudes in North America, Europe,
  and Asia

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Figure 29.24 (Krogh 2000)
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Taiga Climate and Soils

• Long and cold winters with widespread permafrost
• Growing season of 130 days
• Mean annual precipitation between 40-100 cm
  mostly in the form of snow extremely
  water-limited environment hence conifers
• Acidic, humus rich soils with a deep litter layer
• Slow decomposition
• Low microbial activity

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Taiga Vegetation

• Model of species uniformity with dominant tree
  members consisting of spruce (Picea spp.), fir
  (Abies spp.), pine (Pinus spp.), and larch (Larix
  spp.)
• Other members of the canopy include some
  broad-leaf trees like birch (Betula spp.) and
  poplar (Populus spp.)
• Very low light penetration to ground surface and
  therefore forest floor still extremely bare

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Taiga Animals

• Moose, bear, caribou, red squirrel, mink, sable,
  beavers, wolves
• Migratory birds such as warblers and thrush use
  the taiga for nesting sites

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Taiga Environmental Concerns

• Development and oil exploration are concerns due
  to relatively slow recovery from disturbance.
• Other concerns revolve around forestry management
  and the implications of clear- cutting on
  flooding and habitat loss for animals.

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Temperate Forest Primary Region

• Eastern United States
• North Eastern Asia
• Central Europe

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Fig. 50.17, p. 909
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Temperate Forest Climate and Soils

• Well-defined seasons
• Growing season of 140-200 days with 4-6 months
  frost-free
• Mean annual precipitation of 75-200 cm with even
  distribution throughout year
• Temperature range from -30o to 30o C
• Fertile soil
• High microbial activity
• Rapid decomposition high turnover of organic
  material (carbon containing)

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Temperate Forest Vegetation

• Deciduous (loss of leaves in fall with re-growth
  in spring) trees maple, beech, oak, and hickory
• Trees are not dominant, but instead a heavy
  understory of woody and herbaceous plants (plants
  that never develop woody tissue)
• Many herbaceous plants flower in the late spring
  before the trees leaf out such as blue bells
  (Scilla nonscripta) and anemones (Anemone
  nemorosa)

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Temperate Forest Environmental Concerns

• Soil run-off and flooding due to clear-cutting
• Acid precipitation from industrial pollution

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Acid Rain Formation

• Sulfur dioxide (SO2) from coal- and oil-burning
  power plants rises in the air along with nitric
  oxide (NO) and nitrogen dioxide (NO2) which comes
  mostly from cars.
• These molecules combine with hydroxyl radicals
  (OH) in the atmosphere to produce sulfuric acid
  (HSO4) and nitric acid (NO3).
• HSO4 and NO3 combine with atmospheric water
  making acid rain.

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Tropical Rainforest

• Tropical rainforest contain the greatest amount
  of biodiversity on the planet.
• Some estimates as great as 100 tree species per
  square kilometer.
• Great biodiversity thought partially to be the
  result of their long undisturbed history (i.e. no
  glaciation).

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Tropical Rainforest Primary Region

• Near the equator from 23.5o N to 23.5o S

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Fig. 50.16, p. 908
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Tropical Rainforest Climate and Soils

• Distinct seasonality with NO WINTER just dry
  versus rainy seasons
• Mean annual precipitation greater than 200 cm
• Average day length of 12 hours with little
  variation
• Mean temperature of 25o C with coldest and
  warmest months differing by no more than 5o C
• Nutrient poor, acidic soils
• Rapid decomposition and high microbial activity

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Tropical Rainforest Vegetation and Animals

• Great biodiversity
• Exotic trees and plants including orchids and
  palms
• Multi-layered canopy with average tree height of
  25-35 m
• Numerous birds, bats, and insects as well as
  large predators like the tiger and jaguar
• Tree-dwelling lemurs, monkeys, and chimps

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Tropical Rainforest Environmental Concerns

• Destruction of forest resulting in loss of
  biodiversity.
• Destruction of forest greatly affects the global
  carbon cycle, as well as contributes to global
  warming.

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Temperate Grassland

• Grasslands equivalent to the prairies of the
  US, the steppe of Russia, the pampas of
  Argentina, and the veldt of South Africa.
• Primary regions include vast areas of eastern
  Europe and Asia, central North America, and South
  America

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Fig. 50.15, p. 907
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Temperate Grassland Climate and Soils

• Mean annual precipitation of 25-60 cm
• Continental climate with hot summers and cold
  winters
• Soil is high in organic making these areas
  well-suited for crop farming (corn and wheat)

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Temperate GrasslandVegetation and Animals

• Grasses and broad-leafed perennials
• Absence of persistent woody tissue
• Originally migratory herds of grazing animals,
  burrowing mammals, and associated predators
• Few birds due to uniformity of vegetation and
  absence of trees.

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Temperate Grassland Environmental Concerns

• Desertification and loss of topsoil
• Development and expansion leading to loss of
  habitat and biodiversity

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Savanna

• Primary Region Africa, but also areas of
  Australia, South America, and Asia
• Climate and Soil
• Mean annual precipitation of up to 120 cm, all
  occurring in a wet season
• High fire risk during the dry season, not unusual
  to burn out each dry season
• Low soil moisture limiting soil microbial activity

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Savanna

• Vegetation and Animals
• Trees with thick bark to withstand fire (Acacia
  spp.)
• Large populations of grazing animals such as
  wildebeest, zebra, and gazelle
• Browsers (herbivores) such as impala, giraffe,
  and black rhino
• Carnivores such as the hyena, leopard, and lion
• Primary environmental concern is extinction of
  these populations

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Desert and Chaparral

• Primary Region
• Deserts found around 30o N and 30o S latitudes
• Chaparrals found on the shores of the
  Mediterranean Sea and Southern California

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Figure 29.24 (Krogh 2000)
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Desert and Chaparral Climate and Soils

• Mean annual precipitation
• Less than 25 cm in the desert and between 30-80
  cm in the chaparral
• Rain-free period lasting about 4 months

• Mean annual temperature
• Temperature does not define desert
• In the chaparral the winter mean is about 10o C
  and the summer mean is 25o C

• Soils are nutrient poor, well-drained, and thin.

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Fig. 50.13, p. 905
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Fig. 50.14, p. 906
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Desert and ChaparralVegetation and Animals

• Hot desert vegetation includes thorny shrubs,
  ephemeral annuals, underground bulbs, and
  succulents such as cacti
• Chaparral species often have thick drought
  resistant leaves plant community maintained by
  fire
• Birds, reptiles, and insects
• Some mammals which can overcome water loss such
  as camels and rodents

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Desert and ChaparralEnvironmental Concerns

• Diversion of water from seas and lakes for
  irrigation
• Irrigation caused toxic salinization (high saline
  content following large-scale water evaporation
  from the surface

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north temperate
north polar
tropical
Fig. 50.25, p. 915
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Marine Ecosystems70 of Earths surface

• Horizontal dimension
• Coastal zone extends from shore where high tide
  reaches to a point at sea where the ocean floor
  drops off (continental shelf)
• Intertidal zone bordered by low and high tide
  diverse and stratified communities
• Open Sea

Figure 29.31 (Krogh 2000)
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SALT MARSH (estuary)
shallow bay
sound
open ocean
tidal cover
creek
Fig. 50.29, p. 918
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Marine Ecosystems

• Vertical dimension
• Pelagic zone all of the water form the surface
  to the floor (benthic zone)
• Photic zone zone within the pelagic zone where
  the Suns rays penetrate and photosynthesis can
  occur (100 m depth)

Figure 29.31 (Krogh 2000)
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Maine Ecosystem Vegetation and Animals
Figure 29.31 (Krogh 2000)
Pelagic Zone surface seaweed, fish and
mammals Benthic Zone primarily seaweed,
bacteria, fungi, sponges, sea anemones, worms,
sea stars Photic Zone phytoplankton and
zooplankton
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Marine Ecosystem Environmental Concerns

• Pollution, including oil and sewage,
  hydrocarbons, and metals. Pollutants can become
  magnified in the food web, contaminating fish
  stock.
• Recreation and development of intertidal regions
  leading to habitat destruction and pollution.

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Freshwater Ecosystems

• 2.1 Earths surface
• 1 salt concentration

• Littoral Zone
• outer boundary defined as the point where the
  water is so deep that rooted plants can no longer
  grow
• warmest with fairly diverse community (algae,
  fish, amphibians, plants, insects, clams, birds)

Figure 29.33 (Krogh 2000)
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• Limnetic Zone
• starts at the surface and extends to a depth
  where no sunlight can penetrate

• Profundal Zone
• beneath the limnetic zone

Figure 29.33 (Krogh 2000)
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Fig. 50.20, p. 912
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Fig. 50.23, p. 913
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Freshwater Ecosystems Environmental Concerns

• Loss of wetlands due to agriculture and
  development
• Commercial development and pollution and
  resultant loss of habitat and biodiversity
• Eutrophication through organic and inorganic
  pollutants resulting in loss of plant diversity
  and algal blooms
• Eutrophic nutrient rich lakes with abundant
  algal cover
• Oligotrophic nutrient poor deep clear lakes