Principles of Ecology

Principles of Ecology

The Physical Environment

Key Sections

  • Average Annual Precipitation (cm)

  • Climatic Variation and Salmon Abundance

  • Climate: Fundamental for ecological processes.

  • Learning Objectives

    • Differentiate between weather and climate.

    • Understand the role of temperature due to energy gain/loss at Earth's surface.

    • Connect wind and ocean currents to solar radiation differences.

  • Key Concepts

    • Large-scale atmospheric and oceanic circulation impact global temperature and precipitation.

    • Regional climates influenced by oceans, continents, and mountains.

    • Seasonal climate variation associated with Earth's axial tilt.

    • Salinity, acidity, and oxygen concentrations impact chemical environments.

Climatic Variation and Salmon Abundance: A Case Study

  • Salmon Characteristics

    • Anadromous fish: live in ocean but spawn in streams.

    • Significant in Native American culture and commercial fishing.

  • Changes in Salmon Catch over Years

    • Fluctuations attributed to:

    • Stream threats: damming, pollution, overfishing.

    • Ocean changes.

  • Research Insights

    • Hare and Francis (1994): Alternation of high/low salmon production linked to North Pacific climatic variation.

    • Mantua et al. (1997): High production in Alaska correlates with low production in Oregon/Washington and correlates with sea surface temperatures.

  • Visual Data

    • Catch data for Sockeye and Pink salmon from 1925-1985.

Difference Between Weather and Climate

  • Weather: Day-to-day atmospheric conditions (temperature, precipitation, humidity).

  • Climate: Long-term weather patterns based on averages and observed changes over decades.

Climate Determinants

  • Climate influences geographic organism distribution.

  • Climate characterized by average conditions; extreme conditions contribute significantly.

  • Timing of variations (e.g., seasonality of rainfall) is essential.

    • Examples:

    • Mediterranean climate: concentrated winter rainfall.

    • Grassland: evenly spread rainfall.

Energy Balance in the Climate System

  • Incoming Solar Radiation: 100% of total solar energy received.

  • Distribution of energy:

    • Reflected by clouds and surfaces: 32%.

    • Absorbed by atmosphere: 19%.

    • Absorbed by the Earth surface: 49%.

  • Outgoing Longwave Radiation: 68% emitted back to space.

  • Heat Transfer Mechanisms:

    • Conduction: Energy transfer through direct contact.

    • Convection: Energy transfer through moving air or water currents.

  • Sensible Heat Flux: Transfer of energy from warm air above the surface to cooler atmosphere.

Greenhouse Gases

  • Effect of Greenhouse Gases:

    • Traps and re-radiates IR radiation emitted by Earth.

  • Main Greenhouse Gases:

    • Water vapor (H₂O)

    • Carbon dioxide (CO₂)

    • Methane (CH₄)

    • Nitrous oxide (N₂O)

Global Climate Change

  • Definitions & Trends:

    • Climate change signifies a directional change over a minimum of three decades.

    • Significant ongoing climate change as noted by IPCC (2013).

    • First decade of the 21st century was the warmest in 1,000 years; 2016 set record temperatures.

    • Average global surface temperature increased by 0.97°C from 1880 to 2018.

  • Temperature Anomalies and Historical Data:

    • Representation of temperature changes across decades with noted significant variances.

Storm Patterns and Precipitation Changes

  • Global Precipitation Changes:

    • Analyzed changes in annual precipitation rates (in mm/year).

    • Observations indicate diverging trends between equatorial and polar regions.

Atmospheric and Oceanic Circulation

  • Hadley and Polar Circulation Cells

    • Atmospheric pressure influences climate zones (tropical, temperate, polar).

    • Warm air rises creating low-pressure areas at the equator, with cooler air sinking at the poles.

  • Coriolis Effect: Impact on prevailing winds due to Earth's rotation.

  • Global Wind Patterns: Driven by pressure cells; illustrate the easterlies and westerlies.

Ocean Currents

  • Surface Currents: Driven by winds; speed approximately 2-3% of wind speed.

  • Upwelling: Occurs when deep water rises to replace surface water, enhancing nutrient availability.

  • Impact of Ocean Currents on marine ecosystems and fisheries.

Regional Climatic Influences

  • Evapotranspiration: Water loss from soil and plant transpiration affecting local climates.

  • Effects of Deforestation: Influences climate factors such as moisture intervals and heat retention.

Seasonal Variations in Climate

  • Understanding Seasonal Effects: Solar radiation variation influences biological activity and organism distributions.

  • Aquatic Environments: Experience temperature stratification impacting nutrient distribution and oxygen availability.

Changes in Atmospheric Chemistry

  • Salinity and Acidity: Affect ecosystem health; described by pH levels which measure H⁺ concentration.

  • Variation in salinity impacts climatic conditions.

The North Atlantic Oscillation and Pacific Decadal Oscillation

  • Oscillations affecting climate in Europe, Asia, North America, and contexts in which they align with ecological impacts on species like salmon.

  • Examination of temperature fluctuations over time related to ecological outcomes in salmon populations.

Final Summary

  • Key concepts encompass individual and systemic influences of climate on ecological structures and processes, emphasizing cumulative evidence of anthropogenic impacts on climate dynamics across various scales.