Unit 4: Biosphere Flashcards
Define biome.
Biotic community of a certain geographical extent, with distinctive landscape, based on dominant climax species (plants)
What are the major biome determinants?
- T
- Moisture, humidity
- Soil
- light
- species interactions
- precipitations
What are the 3 major biomes of Qc and Can?
- Temperate deciduous forest
- Boreal coniferous forest
- Tundra
What are the 2 minor biomes of Qc and Can.?
- Temperate rainforest
2. Temperate grossland (prairies)
What are the characteristics of Temperate deciduous forest
- South of Qc
- warm summers, cold winters
- Growing season: 125-150 days/y
- Precipitations: fairly high and well distributed
- Trees: large, tall, deciduous
- Soil: acidic
What are the characteristics of Boreal coniferous forest
- Most of Qc and Can
- short, mild summer; long, cold winters
- Growing season: 100-120 days/y
- Precipitations: low, but heavy snowfall
- Low evaporation = humid climate
- Trees: short, low diversity
- Soil: acidic
What are the characteristics of Tundra
- Up north
- cool, short summers, long, cold winters
- Growing season: < 100 days/y
- Precipitations: low, air is dry
- Smaller animals, less food available.
- Photoperiod: long in summer, short in winter
- Permafrost: permanently frozen soil
- Pounds: permafrost that tawed
- Grasses: only small plants can grow because of shot growing season.
What are the characteristics of Temperate rainforest
- Canada’s west coast
- warm, dry summers, wet, mild winters
- Precipitations: high
- Animals and plants (high and big trees) similar to Boreal forest
What are the characteristics of Temperate grossland (prairies)
- Canada’s prairies
- Precipitations: low, droughts (long periods without rain)
- Grasses, lots of grasses to feed the animals
What is the dominant biome in canada?
Boreal coniferous forest
Why do Boreal coniferous forest have a lower diversity?
Short growing season
Thin soil layer, mostly frozen
Conifers are favored because don’t waste energy to grow leaves and more resistent to cold temperatures and desiccation
Needles shed snow easily, not a lot of competition (stable), animals will not eat needles.
Define ecotone.
Transitional area between 2 biomes.
What is the Taiga-Tundra ecotone?
Transitional area between boreal forest and tundra.
What is the Aspen parkland ecotone?
Transitional area between boreal forest and prairie. (aspen trees)
Are aquatic ecosystems more subject to small scale variations than terrestrial ecosystems?
Yes more subject to variations of light, gases, T, salinity
Describe what a watershed is.
A watershed is an area of land that drains all the streams and rainfall to a common outlet, water within the watershed boundary exits at the same place.
What factors influence water runoff?
- topography (slope of terrain)
- geology (porous, rock, clay
- vegetation
- human impact
Define pollutants.
Something that modifies the physical, chemical and biological properties of water or organisms living there.
Give examples of the categories of pollutants.
Chemical: acids, nutrients, oil, salts
Physical: plastics, turbulence, water T, salinity
Biological: cyanobacteria, parasites, viruses
What are the freshwater main items of water?
- Stream and rivers : heterogenous conditions, bring nutrients to lakes
- Lakes
What are the different zones in a lake and what do they contain?
- Littoral: water close to the cost, aquatic plants, shore area, light penetrates to the sediments, dominated by macrophytes, PP, high E
- Limnetic: water away from the cost, away from the shore, light usually doesn’t reach the sediments, dominated by microalgae
- Benthic: Soil and sediments at the bottom of the lake= + nutrients, invertevrates and bacteria
- Euphotic: Depth to which light can reach in the water, enough light so that life can grow
Between a shallow and a deep euphotic zone, which one will have the highest number of top predators?
Deep because more light, more PP, more organisms to feed on, more consumers, more energy available at top of pyramid.
In lakes, in which zone do you expect to find the highest number of trophic levels?
Littoral zone because it is where there is the most primary producers, so most energy available = most trophic levels
In lakes, in which zone do you expect to find the highest biodiversity?
In the littoral zone, because there is more light = more resources = more primary and secondary consumers = more competition for resources = more specialization = more biodiversity
What are the 3 steps of a lake succession?
- Oligotrophic: nutrient poor.
- Mesotrophic
- Eutrophic: nutrient rich
from 1 to 3, increase in nutrients, productivity, biomass and diversity
What is the rate at which plants convert sunlight into energy called?
Gross primary productivity
Which ecosystem contributes most to global net primary productivity?
Open ocean
How much of the sun’s energy do plants harness?
1 %
Why is the number of trophic levels supported by an ecosystem limited?
Not enough biomass in top carnivores to support another trophic level.
Describe eutrophication.
Natural process by which a body of water becomes overly enriched with nutrients, causing extensive plant growth.
What can inhance eutrophication? Give specific examples.
Human activities: agriculture, fertilizers, boats, deforestation
Why can extensive plant growth be bad?
Eutrophic lake means that no sunlight goes to the bottom of the lake. Also, no O2 at the bottom of the lake because when top plants die and sink, they get decomposed and the layer at the bottom is depleated of oxygen. (hypoxia)
Eutrophication can cause hypoxia. What is hypoxia?
Depletion of O2 to relatively low levels when plants die and get decomposed at the bottom of a lake.
Define estuaries.
Partially enclosed coastal body of water in which freshwater runoff dilutes salty ocean water (pts of contact between river and gulf, between freshwater and salty ocean water)
What are the types of estuaries?
- coastal plain
- fjord
- bar-built
- tectonic
Do estuaries have a high biodiversity?
Yes because of the strong gradients in T and salinity, it creates many different and diverse habitats where different and diverse animals and plants live.
What is water stratification in estuaries circulation?
Different water masses with different properties (T, salinity, thus density) form layers that prevent them from mixing. Layered water = stratified water
How is density affected by:
a. T
b. salinity
a. T increases, density decreases
b. salinity increases, density increases
What are the types of marine environments?
- wetlands
- open oceans
Define wetlands.
Highly salty water, thus plants resistant to high salinity are present and their roots are in sediments
What are the habitats of open oceans and what is different from 1 to the next?
- surface: light
- bottom: no light
- near coast
- far from coast
Different T, salinity, light, nutrients = diversity in organisms
Why does light penetration in open ocean goes way deeper than in coastal waters?
More nutrients = more plants in coastal waters = sediments from coast get in the water = light cannot penetrate to the bottom = looks greenish/brown
Water is clearer in open oceans: PP mostly at the surface because that is where most light is available.
How does ocean circulation work and what does it affect?
The ice melting at the poles create currents and make the water circulate = plays a major role in heat distribution around the world
What causes ocean currents and what does it affect?
Wind and coriolis force create currents = plays a major role in heat distribution and vertical mixing (mixes the stratified layers)
-impacts organisms because it changes the nutrients, the T and dispersal of organisms.
What can prevent vertical mixing and why would you want that?
Except when huge winds, water stratification will prevent vertical mixing so the nutrients will stay at the bottom and the algae at the top.
What are upwellings?
- Usually happens close to the coast, at the poles or at the equator
- COAST: Winds push water away from the shore or parallel to the shore, which pushes water away from coast. Consequently, the pushed away water needs to be replaced and water from the bottom replaces it. This process brings new nutrients back up to the surface.
- POLES/EQUATOR: when ice melts, the water goes down and new water with new nutrients goes up = increases productivity
Describe the winter dynamic in terms of light, T, nutrients and phytoplankton.
↑ nutrients
↓ light
↓ T
↓ primary productivity
Light is the limiting factor.
Density similar from surface to bottom so no stratification = vertical mixing = nutrients everywhere
Describe the summer dynamic in terms of light, T, nutrients and phytoplankton.
↓ nutrients
↑ light
↑ T
↓ primary productivity
Nutrients are the limiting factor.
Heat at surface but not bottom so stratification = no vertical mixing = no nutrients at surface replenished
Describe the fall dynamic in terms of light, T, nutrients and phytoplankton.
↑ nutrients
↓ light
↓ T
↑ primary productivity
Light is the limiting factor.
Density similar from surface to bottom so weak stratification = some vertical mixing = nutrients back to the surface
Describe the spring dynamic in terms of light, T, nutrients and phytoplankton.
↑ nutrients
↑ light
↑ T
↑ primary productivity
Heat at surface but not bottom but not enough variation in density so no stratification = vertical mixing = nutrients at surface replenished
What are the major effects of ice on marine ecosystems?
- Effects on light availability (meltponds act as windows where light can penetrate the water)
- Creates a barrier for wind (↓ effects of wind and vertical mixing = lack of nutrients at the surface)
How can a fracture in the ice (lead) impact marine ecosystems?
Very cold air can go through = cold water:
- ↓ metabolic rate
- ↑ water density, so top water sinks and brings the phytoplankton at the bottom where no light can reach it = phytoplankton dies below lead
