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lecture 4 pt 1 Ecosystem Essentials Notes

Ecosystem Essentials

Definition of Ecosystem

  • A biological community of interacting organisms and their physical environment.

  • Consists of biotic (living) and abiotic (non-living) components.

  • Components linked through:

  • Nutrient/matter cycles.

  • Energy flows.

  • Characteristics:

  • Holistic approach.

  • Somewhat self-contained.

  • Transitional zones called ecotones.

  • Each component has a distinct role.

  • Interconnected elements operate at different scales.

Ecology

  • Study of relationships and interactions among living organisms and their environments across various scales.

  • Links Earth science, biology, and geography.

  • Biogeography:

  • Focuses on the distribution of plants and animals.

  • Examines physical and biological processes that contribute to Earth's species richness.

Landscape Ecology

  • Subdiscipline of ecology focusing on how landscape structure influences organism abundance and distribution.

  • Landscape Structure:

  • Composition (e.g., types of land cover) and configuration (e.g., arrangement of landscape elements).

  • Involves examining habitat fragmentation.

  • Important for regional development studies.

Ecological Footprint

  • Represents the impact of a person or community on the environment.

  • Measured by the biologically productive land and water required for resource production and waste assimilation.

  • Significance:

  • Key measure of human demand on nature.

  • Indicates how human activities consume resources and produce waste.

Ecosystem as a Closed System

  • Ecosystems as networks of relationships with interactive parts:

  • Open Systems: Allow for the exchange of energy and matter with the environment.

  • Closed Systems: Energy input and output occur, but matter cycles among components.

Biotic and Abiotic Components

  • Biotic: Refers to living organisms.

  • Abiotic: Encompasses non-living environmental factors.

  • Key roles:

  • Producers: Create energy via photosynthesis.

  • Consumers: Use energy created by producers.

  • Decomposers: Break down dead organic material.

The Role of the Sun

  • Solar energy is crucial for Earth’s ecosystems.

  • Powers photosynthesis, which converts sunlight into chemical energy in plants.

  • Only 1% of solar energy is captured by photosynthesis as carbohydrates (baby plants).

  • Critical link between solar energy and the biosphere.

Photosynthesis vs. Respiration

  • Photosynthesis:

  • Plants convert sunlight, CO2, and nutrients into oxygen (O2) and carbohydrates (sugars).

  • Respiration:

  • Reverse process where sugars and O2 are used to produce CO2 and release energy.

  • Net Photosynthesis: Balance determining plant growth, must exceed a compensation point for growth.

Net Primary Productivity (NPP)

  • Measurement of the ecosystem's net photosynthesis.

  • Indicates the amount of stored chemical energy, vital for supporting consumers in the ecosystem.

Biochemical Cycles

  • Recycling of gases and nutrients essential for life:

  • Hydrogen, oxygen, and carbon make up 90% of Earth's biomass.

  • Significant nutrients:

  • Nitrogen, calcium, potassium, magnesium, sulfur, and phosphorus.

The Carbon and Oxygen Cycles

  • Carbon is fixed through plants during photosynthesis, releasing oxygen.

  • Respiration and human activities return carbon to the atmosphere.

The Nitrogen Cycle

  • Key processes include:

  • Nitrogen Fixation: Conversion of atmospheric nitrogen by bacteria into ammonia.

  • Nitrification: Ammonia converted to nitrite then nitrate for plant use.

  • Denitrification: Conversion of nitrates back to atmospheric nitrogen by various organisms.

Harmful Algal Blooms

  • Caused by nutrient runoff, leading to:

  • Ecosystem destruction and dead zones.

  • Neurotoxins harmful to various species including humans.

  • Associated issues include hypoxia and costs of water treatment.

Biodiversity

  • Definition: Variety of life in a habitat or ecosystem.

  • Levels of biodiversity include:

  • Ecosystem diversity.

  • Species diversity.

  • Genetic diversity.

  • Importance: Maintains ecosystem resilience and function.

Human Impact on Extinction

  • Historical extinction patterns associated with human arrival in regions:

  • Notable loss of species across continents, implicating human activities.

  • Current extinction rates are concerning, prompting thoughts of a potential sixth extinction driven by human actions.

Habitat Fragmentation

  • Resulting from human development leading to isolated habitats.

  • Impacts species survival as available environments diminish and become fragmented.

Conservation Efforts: Wildlife Corridors

  • Innovations like overpasses and underpasses at sites like Banff National Park help maintain wildlife movement and mitigate fragmentation effects.

lecture 4 pt 2 In-Depth Notes on Terrestrial Biomes and Invasive Species

Terrestrial Biomes

Biogeographic Realms

  • Definition: Geographic regions where a group of associated plant and animal species evolved, also known as ecozones.

  • Global Realms:

  • Neararctic

  • Neotropical

  • Palearctic

  • Afrotropical

  • Indo-Malay

  • Australasian

  • Oceanic

  • Antarctic

Biomes

  • Definition: Large, stable terrestrial or aquatic ecosystems classified by predominant vegetation and adaptations of organisms.

  • Characteristics:

  • Defined by native species

  • Determined by identifiable vegetation

  • Six Major Groups of Terrestrial Vegetation:

  • Forest

  • Savanna

  • Shrubland

  • Grassland

  • Desert

  • Tundra

The Forest Group

  • Subdivisions:

  • Rain forests (tropical, temperate)

  • Seasonal forests (deciduous trees)

  • Broadleaf mixed forest

  • Coniferous forests

Ecosystem vs Biome

  • Ecosystem: Interaction of living and nonliving things in an environment (a system - process).

  • Biome: A specific geographic area known for its species (an area - pattern); may contain multiple ecosystems.

Ecotone

  • Definition: Boundary zone between adjoining ecosystems, characterized by gradual transitions in species composition.

  • Features:

  • High biodiversity

  • Species with varying habitat tolerance

Earth's Major Terrestrial Biomes (Diagram Overview)

  • Distribution of major biomes globally including:

  • Tropical rainforest

  • Tropical savanna

  • Midlatitude forests

  • Boreal forests

  • Deserts

  • Tundra

Canada's Terrestrial Biomes

  • Includes various types of forests, grasslands, and tundra.

  • Highlights regions such as:

  • Boreal forests

  • Coastal temperate rainforests

Boreal Forest

  • Origins: Emerged after the last Ice Age (10,000 years ago), major biodiversity established around 5,000 years ago.

  • Global Significance: Largest land-based biome (29% of global forest cover).

  • Biodiversity: Home to 85 mammals, 130 fish, 32,000 insects, and 300 birds.

Mid-Latitude Grasslands

  • Characteristics:

  • Located in middle latitudes, large terrains of grasses and herbs

  • Climate and soil type determine plant life

  • Drought and fire prevent large forest growth

Tall Grass Prairie Preserve in Manitoba

  • Historical context of complex ecosystems transformed by settlers.

  • Presently, only less than 1% remains of former prairies.

Coastal Temperate Rainforest

  • Rarity & Productivity: Among the rarest ecosystems with the highest biomass of any ecosystem.

Anthropogenic Biomes

  • Definition: Biomes influenced by human activities (land use, agriculture, urbanization).

  • Significance: Most extensive is rangelands (32% of Earth’s land).

Invasive Species

  • Definition: Non-native species causing environmental or economic harm.

  • Examples:

  • Purple Loosestrife: Dominates wetlands, reduces habitat diversity.

  • Zebra Mussels: Invasive clams affecting native mussels and ecosystems.

  • Asian Carp: Introduced species threatening native fish populations and ecosystems.

Zebra Mussel Distribution

  • Historical spread in Ontario lakes and rivers over the years, including impact maps.

Asian Carp

  • Characteristics and impacts, especially on native species, and measures taken to control their spread.

Asian Long-Horned Beetle

  • Threat to trees by disrupting nutrient transport; infestation in Canada leading to quarantines and eradication efforts.

Canada’s Invasive Species Strategy

  • Approaches:

  • Prevention

  • Early detection

  • Rapid response

  • Management of established invaders

  • Strategies for control and eradication of invasive species.

Lecture 5

Solar Energy to Earth and the Seasons

&

Earth’s Modern Atmosphere

Solar Energy to Earth and the Seasons
What is the Sun?

  • Location: A star in the Orion Spur of the Sagittarius Arm.

  • Mass: Enormous mass necessary for sustaining nuclear fusion.

  • Core Conditions: High pressure and temperature, allowing hydrogen atoms to fuse into helium, releasing energy.

Solar Energy

  • Definition: The primary energy source for life on Earth.

  • Photosynthesis: Solar energy enters ecosystems through photosynthesis.

  • Fixed Solar Energy: Only 1% of solar energy captured as carbohydrates.

Solar Activity

  • Solar Cycle: Periodic changes in solar activity and appearance.

  • Sunspots: Magnetic storm disturbances on the Sun's surface.

    • Solar Minimum: Few sunspots present.

    • Solar Maximum: Many sunspots present, some larger than Earth.

  • Not Related to Climate Change: Solar cycles have not increased global temperatures in recent decades.

Magnetic Storms & Solar Flares

  • Occurrence: Mainly during solar maximum.

  • Solar Flares: Result from magnetic storms; cause gas eruptions from the Sun.

Solar Wind

  • Definition: Charged particle clouds emitted from the Sun's corona.

  • Impact on Earth: Takes about 3 days to reach Earth; interacts with the magnetosphere, impacting Earth’s poles.

Earth's Magnetic Shield

  • Significance: Earth's magnetic field protects from solar radiation, allowing liquid water and life.

Coronal Mass Ejections (CMEs)

  • Definition: Massive releases of charged particles that can generate auroras.

  • Types of Auroras:

    • Aurora Borealis: Northern lights.

    • Aurora Australis: Southern lights.

Disruption of Telecommunication Systems

  • Effects: Solar winds can disrupt radios and satellites, causing electrical overloads.

Electromagnetic Spectrum of Radiant Energy

  • Overview of various types of radiant energy, including visible light and their wavelengths and applications.

Earth's Energy Budget Simplified

  • Input: Incoming solar radiation (shortwave radiation).

  • Output: Longwave radiation (thermal infrared) emitted back into space.

Energy at the Top of Our Atmosphere

  • Thermopause: Outer boundary of Earth’s energy system.

  • Insolation: Amount of solar radiation reaching Earth, primarily at the thermopause.

Uneven Distribution of Insolation

  • Subsolar Point: Location on Earth where insolation is received perpendicularly; moves between Tropic of Cancer and Tropic of Capricorn.

Solar Radiation Dynamics

  • Behavior: Solar radiation is affected by scattering, absorption, and reflection.

Seasonality

  • Definition: Variation in the Sun’s position and day-length throughout the year.

  • Sun’s Declination: Latitude of the subsolar point indicating seasonal changes.

Variation of Seasons

  • Contributors: Changes in sun's altitude and declination, day lengths, and climate change impacts.

Solstice and Equinox

  • Solstice: Occurs when the subsolar point is at Tropic of Cancer (June 21) or Tropic of Capricorn (December 21).

  • Equinox: Equal day and night lengths at the equator (March 21 and September 21).

Day-Length Variations

  • Equatorial Constant: Consistent day and night hours at the equator.

  • Poles Extremes: Long periods of night or day.

The Earth’s Atmosphere

  • Composition: Atmosphere is made up of nitrogen, oxygen, argon, carbon dioxide, and trace gases.

  • Temperature: Varies with altitude across different layers.

  • Function: Protects life by filtering harmful solar radiation, maintaining the climate, and facilitating weather phenomena.

Atmospheric Composition

  • Main Components: Key gases include nitrogen (78%), oxygen (21%), argon (0.93%), and carbon dioxide (0.04%).

  • Variable Components: Water vapor (0-4%), aerosols, and pollutants affecting air quality.

  • Stratification: Layers of atmosphere (troposphere, stratosphere, mesosphere, thermosphere, exosphere) with differing compositions and temperatures.

Climate Variation

  • Influences on climate include Earth’s tilt, orbit, and solar activity. Seasonal changes are driven by the position of Earth relative to the Sun.

Atmospheric Pressure

  • Definition: The weight of air above a surface; decreases with altitude.

  • Impact: Affects weather patterns and oxygen availability at higher elevations.

Temperature and its Measurement

  • Instruments: Thermometers measure temperature, essential for understanding energy balance and climate.

  • Variations: Day/night and seasonal temperature changes impact ecosystems and weather.

Humidity and Precipitation

  • Definition of Humidity: The amount of water vapor present in the air, affecting temperature and weather.

  • Forms of Precipitation: Includes rain, snow, sleet, and hail, which are influenced by atmospheric conditions.

Wind Patterns

  • Global Circulation: Driven by solar heating differences across Earth’s surface; impacts weather and climate.

  • Local Winds: Occur due to local temperature differences, e.g., sea breezes.

Ozone Layer

  • Location: Found in the stratosphere, protective against harmful UV radiation.

  • Importance: Essential for life on Earth as it shields organisms from UV radiation that can cause health issues and environmental damage.

Greenhouse Effect

  • Definition: Natural phenomenon where certain gases trap heat in the atmosphere, maintaining Earth's temperature.

  • Enhanced Greenhouse Effect: Result of increased greenhouse gas emissions, leading to global warming and climate changes.

Climate Change Indicators

  • Changes in temperature, precipitation patterns, ice melt, and sea-level rise serve as indicators of climate change's impact.

Human Impact on Climate

  • Activities: Industrialization, deforestation, and burning fossil fuels contribute to increased greenhouse gas concentrations.

  • Consequences: Impacts weather patterns, ecosystems, and biodiversity.

Mitigation Strategies

  • Approaches to reduce carbon emissions include renewable energy sources, energy efficiency measures, and reforestation efforts.

Importance of Sustainability

  • Definition: Meeting present needs without compromising future generations’ ability to meet their needs.

  • Practices: Emphasis on conservation, responsible resource use, and environmental protection.

Lecture 6 Part 1 Notes on Earth's Energy Balance and Heat Transfer

Earth’s Energy Balance

  • Definition: The balance between solar radiation inputs (insolation) and outputs of the earth (radiation to space).

  • Insolation: Solar radiation intercepted by Earth (incoming solar radiation).

  • Inputs: Shortwave radiation (UV, visible light, near-infrared wavelengths).

  • Outputs: Longwave radiation (thermal infrared wavelengths).

  • Transmission: Energy passes through the atmosphere without interruption.

Earth’s Energy Budget

  • Steady-State Equilibrium: Overall energy system remains balanced but varies by location on Earth.

Energy and Heat

  • Heat Definition: Flow of kinetic energy between different bodies resulting from temperature differences.

  • Kinetic Energy: Energy of motion linked to molecular vibration measured as temperature.

Sensible Heat vs Latent Heat

  • Sensible Heat: Heat we can sense, associated with temperature.

  • Latent Heat: Energy involved in phase changes of substances (e.g., liquid to gas).

Methods of Heat Transfer

  1. Radiation:

  • Transfer of heat via electromagnetic waves that can travel through vacuums.

  • Wien’s Law: Hotter objects emit shorter wavelengths.

  1. Conduction:

  • Molecule-to-molecule heat transfer through materials.

  • Efficiency of transfer varies by material conductivity.

  1. Convection:

  • Physical mixing or circulation of heat, often involving vertical motion in fluids.

  • Warmer, less dense substances rise; cooler, denser ones sink.

Examples of Heat Transfer in Environment

  • Radiation and Conduction:

  • Differences in temperature between land and water, lighter and darker surfaces, soil layers.

  • Convection:

  • Atmospheric and oceanic circulation, air mass movements, and internal Earth motions.

  • Advection:

  • Horizontal wind movements among land and sea.

Insolation at the Earth's Surface

  • Variation in solar radiation received across different regions of the Earth.

  • Average annual solar radiation represented in watts per square meter.

Energy Budget by Latitude

  • Equatorial regions: Energy surplus due to direct sunlight.

  • Polar regions: Energy deficit; energy is transported poleward from surplus areas.

Daily Solar Radiation Patterns

  • Key Moments: Midnight (coolest), Local Noon (warmest), Lag after noon.

  • Temperature variations throughout the day due to insolation absorption and release.

Scattering

  • Definition: Insolation reflected back into space.

  • Influencers: Atmospheric gases, dust, water vapor, and pollutants.

  • Diffuse Radiation: Scattered energy reaches Earth without shadows.

Scattering Principles

  • Rayleigh’s Scattering: Shorter wavelengths scatter more (blue sky effect), longer wavelengths scatter less (red sunsets).

  • Mie Scattering: Larger particles scatter all color wavelengths evenly resulting in white light.

Refraction

  • Definition: Bending of insolation as it moves through different mediums like air and water.

  • Effect: Causes phenomena like rainbows and extended daylight at sunrise/sunset.

Reflection and Albedo

  • Reflection: Portion of energy bounces back into space.

  • Albedo: Reflective quality of surfaces, with higher percentages for lighter surfaces.

Absorption

  • Energy Assimilation: Radiation absorbed by materials converts to heat or chemical energy.

  • Breakdown of incoming solar radiation absorption:

  • 31% reflected,

  • 45% absorbed by surfaces,

  • 24% absorbed by atmosphere.

Atmospheric Gases and Aerosols

  • Selective Absorption: Oxygen and ozone absorb UV radiation; CO2 and water vapor absorb longwave radiation.

  • Aerosols Impact: Volcanic eruptions can cool the climate by injecting particles into the atmosphere.

Global Dimming

  • Decline in insolation from pollution: Haze can cool Earth, leading to less evaporation and moisture.

Greenhouse Effect

  • Delays longwave radiation escaping to space, essential for life by maintaining warmth on Earth.

  • Gases involved: CO2, methane, nitrous oxide, and water vapor.

Effects of Clouds

  • Dual function: Can cool (reflecting sunlight) and warm (trapping heat).

  • Impact based on cloud cover, type, altitude, and thickness.

Urban Heat Island (UHI) Effect

  • Urban areas retaining heat due to buildings and surfaces like pavements.

  • Temperature can be significantly higher within urban areas compared to rural areas.

  • Solutions: Green roofs mitigate heat absorption.

Solar Power

  • Pros: Renewable, low maintenance, no operational emissions.

  • Cons: Environmental impact from production and disposal, energy storage challenges.

How Solar Panels Work

  • A functioning mechanism to convert solar energy into usable power.

Lec 6 Pt 2 Notes on Global Temperatures and Related Concepts

Measuring Temperature

  • Temperature is a measure of the average kinetic energy of individual molecules in matter.

  • It is essentially a measure of heat.

  • Daily or hourly air temperature readings are taken at 16,000 weather stations worldwide, coordinated by the Global Climate Observing System (established by the World Meteorological Society and other organizations).

  • Satellites measure land-surface temperature (LST), which is the heating of the land surface from insolation and other heat flows.

  • LST is typically highest in dry environments with clear skies and low albedo.

Global Average Temperature

  • Average global temperatures are influenced by isotherms, which are lines on a map connecting points having the same temperature at a given time or over an average period.

Earth’s Hottest Places

  • Death Valley, California is considered the hottest place on Earth in terms of air temperature.

  • In terms of LST, regions in Iran, China, and Australia have recorded higher temperatures.

  • Highest LST recorded in 2008 was in the Turpan Depression, China (66.8°C) compared to the world record surface temperature of 56.7°C in Death Valley, USA.

  • LST generally exceeds air temperature due to the absorption of solar radiation by surfaces, leading to heating and subsequent emission of infrared energy.

  • Highest LST from 2003 to 2009 was recorded in the Lut Desert, Iran at 70.7°C.

Latitudinal Effects on Temperature

  • The temperature of the Earth varies with latitude:

  • Continually warm at the equator.

  • Seasonally variable temperatures at mid-latitudes.

  • Continually cold at the poles.

Altitude and Elevation

  • In the troposphere, temperature decreases with increasing altitude.

  • Altitude refers to heights above Earth's surface, while Elevation refers to the height of a point above sea level.

  • The normal lapse rate is about 6.5°C for every 1,000 meters increase in altitude.

Cloud Cover

  • Cloud cover moderates temperature by raising minimum nighttime temperatures and lowering daily maximum temperatures.

Land-Water Temperature Differences

  • Land heats and cools faster than water, with evaporation over water resulting in cooling effects.

  • Water's specific heat capacity is four times that of soil, allowing it to store heat energy over a greater depth and volume.

  • Ocean currents mix cooler and warmer waters, regulating coastal temperatures more effectively than land.

Continental and Maritime Climate

  • The differential heating of land and water results in contrasting marine (more moderate) and continental (more extreme) climates.

Measuring Global Average Temperature

  • To calculate global average temperature, scientists measure temperatures worldwide and convert them to temperature anomalies, which reflect deviations from long-term averages.

  • Multiple research groups globally have identified an upward trend in temperature anomalies.

Temperature Anomalies

  • A temperature anomaly signifies a departure from long-term averages:

  • Positive anomalies indicate temperatures above average.

  • Negative anomalies indicate temperatures below average.

Heat Wave

  • Defined as a prolonged period of abnormally high temperatures, usually associated with humid weather and low winds.