BIOL208 Lecture 4: Lecture 4 Biomes
10 Oct 2018
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Lecture 4 Biomes
What is Biome and what are some examples of biomes in Canada
Review from lecture 4
The sun
• The equator receive more radiation and the pole receive more diffuse radiation
• Summer, sun is overhead of tropic of cancer and winter, on the tropic of capricon (more
equatorial)
Global atmospheric patterns
• Wind comes from the west in the northern hemisphere to the right counter-clockwise)
• Wind to left on the southern hemisphere (clockwise)
Global precipitation patterns (Alberta example)
• Alberta have rocky mountain with warm mass from the ocean, rises to get over the mountain
and it cools, precipitate out and drop and lose it's moisture
Biomes
• Location of the biomes depends on what support the
dominant life forms
• Biomes are clusters of ecosystem within a extensive
geographic range
• Defined by the morphological and physiological trains of
their dominant organism
• The location and boundaries of biomes are influenced by the
distribution of environmental conditions that support the
species that are their dominant form
• Need to know why each biomes is where it is (mostly due to
climate and soil)
How to describe the patterns on climate diagrams?
• Refer to figure 1
o First Y axis is the temperature and the second Y axis is the precipitation
o X shows time
o Blue dots: mean monthly precipitation
o Red dots: mean monthly temperature as given on the left axis
o No shading indicates that mean minimum temperature for the month is below freezing
o Shading indicates that mean minimum temperature for the month is above freezing
Figure 2
• Gold shading shows that temperature line lies above
precipitation line during warm months
• Blue shading shows that temperature line lines below
precipitation line during cold months
• Temperature scape originates below 0 degress in climate
diagram depicting cold climates
Soil
A complex mixture of living and non-living material upon
which most terrestrial life depends. It can consist of rocky
fragments, minerals, organic matter, moisture, gases and
organism.
• Soil is where the primary terrestrial life grows on
How soil is formed: Weathering
1. Mechanical weathering: Breakdown of rock into smaller particles from the combined action of water,
winds and plants
2. Chemical Weathering: action of chemical process such as oxidation, hydrolysis and reduction that
break down and reform rocks and mineral ex: iron oxide
Factors that influence soil formation
1. Parent material: What is the bedrock (regolith)
• it’s the actual oceanic crust that was shuff up. An actual earth’s crust that meet the continental crust.
• Bedrock in canada contain inorganic debris from glacier
2) Site history: How have past events influenced this site?
• A lot of glaciation
• Past events will influence the type of soil in the are
3) Climate: How do temperature and precipitation influence process such as leaching?
• Warmer weather is faster in decomposition→ thinner soil
• Leaching is the movement of solute through the soil, where movement of substances
through suspended water
• Colder climate has thicker soil because decomposition is not as fast. It has slow build-
up of decomposition
4) Biota: How do organism influences weathering and decomposition?
• Bacteria, fungi can help in decomposition
5) Topography: Are there slopes to alter erosion and runoff?
• slopes alter the runoff and erosion
6) Time: How long has soil formation been occurring at the site?
• Good soil takes 2 thousand and 20 thousand years to form
Soil: foundation of terrestrial Biomes
Soil: the upper layer of the earth’s land surface, consisting of organic matter and minerals.
• A complex mixture of living and non-living material upon which most terrestrial life depends
• There is more organic carbon stored below ground then above ground
Layers of soil
At the surface of the soil lies the majority of the organic matter
1) O (organic horizons) or the LFH horizon:
• O (organic horizons): the most superficial soil layer
containing substantial amounts of organic matter,
including whole leaves, twigs, other plant parts, and
highly fragmented organic
o Are found in soils in which the plants
materials is primarily aquatic in nature (peat
or mosses)
• LFH Horizons: the L, F, and H layers, known
collectively as the LFH horizon, consist of leaves,
twigs, and other organic materials. LFH horizons are
found primarily in upland habitats such as whole
leaves, twigs, flowers and fruits
(Leaf litter, fermentation and humis (well-decomposed organic material)
• The organic litter is the food source and home to wide variety of organism, and their
activity results in the deeper portions of the organic horizon
o Contain: highly fragmented and partially decomposed organic matter
o Small organic horizons: are found in areas with little litter deposition (ex:
deserts and farmland) or high decomposition rates (tropical rain forest)
o Deep organic horizons: found in areas with substantial litter inputs/ and or low
decomposition rates (e.g bogs and fens)
Thickness of humis layer (organic layer)
• Dessert: Thin in desert because of less moisture, decomposition is lower, not much plants to
decomposed, takes longer to decomposed
• Temperate soil: more in depth, Thin (slow)
• Tropics: thinner soil, you've got decomposition happen so fast, plants can absorb the nutrients very
quick because of the decomposition so fast
(Temperate is thicker, tropical and desert is thinner)
2) A horizons: contains a mixture of mineral materials, such as clay, silt, and sand, organic material
derived from the organic horizon (mixture of decomposing organic matter, mineral and
inorganic matters, more mineral components)
• Supports substantial biological activity, including burrowing animals, such as earthworms,
which can mix organic matter from the organic horizon into the A horizon
• Rich in mineral nutrients, essential for plant growth
• Leached: into in the clays, iron, aluminum, silicates and humus (partially decomposed
organic matter
3) B Horizons: a subsoil in which materials leached from above, generally from the A horizon,
accumulate. May be rich in clay, organic matter, iron, and other materials.
(large fragment of mineral, plants, leached nutrients from organic component comes down)
4) C horizons: a soil layer composed of largely unaltered parent material, little affected by
biological activity.
• Consisting of weathered parent materials, which has been broken down through the
actions of frost, water, microbials activity and deeply penetrating roots
o This weather results in the production of the sand, silt and clay
o Under C horizons is bedrock
• Plant secrete, Root exudates: organic compounds, such as amino acids, enzymes, and
carbohydrates, that are secreted by plant roots into the surrounding soil
• The growth and activity of these organism provide stability to the mineral component on
soil, allowing development and maintenance of air spaces and cavities within the soil
o Climates affect
▪ rate of weathering of parent material
▪ leaching
▪ Soil decomposition by impacting the activity of soil organism
▪ Soil species influencing the type and amount of plant species that can
grow
Soil Properties
Color
• Black=organic matter
• Red=Iron
• White= calcium, magnesium, kaolin or gypsum
Texture
• Gravel (>2.00mm)
• Sand (0.05 -2.00 mm)
• Silt (0.002-0.05mm)
• Clay (<0.002 mm)
Depth
Influenced by climate of that region and is important because deeper soil allows for taller plants to
grow (hold more water)
• Influenced by slope, weathering, parent materials and vegetation.
