The Physical Environment

Outline of Topics

  • Physical Environment:

    • Climate and climate variation

    • Human impacts on climate

    • Peer-reviewed literature

    • Primary and secondary literature

    • Tips for reading and understanding

    • Applying these skills to a real paper

Ecology

  • Definition:

    • Ecology is the scientific study of how organisms interact with each other and their environment.

    • These interactions determine the distribution and abundance of organisms.

The Physical Environment

  • Role of Physical Environment:

    • Determines where organisms can live.

    • Determines resources available to organisms.

    • Affects the rate of population growth.

  • Components of the Physical Environment:

    • Climate: Long-term trends in temperature, wind, and precipitation.

    • Solar radiation drives climate systems, influenced by human impacts.

    • Chemical Composition:

    • Composition of air, water, and soil including salinity, acidity, and gas concentrations.

Energy Balance

  • Energy Inputs and Outputs:

    • Energy In: Shortwave, high energy (light + UV).

    • Energy Out: Longwave (IR), low energy (heat).

Greenhouse Effect

  • Natural Greenhouse Effect:

    • Greenhouse gases (GHGs) in the atmosphere absorb and re-radiate some infrared radiation.

    • Raises Earth’s temperature to livable range (from 0˚F to 59˚F).

  • Enhanced Greenhouse Effect:

    • Additional GHGs from human activities raise temperature further, contributing to climate change.

Latitude and Solar Radiation

  • Variation in Solar Radiation:

    • At the poles, sunlight spreads over a larger area and takes a longer path through the atmosphere.

    • Near the equator, sunlight strikes Earth perpendicularly.

Seasonal Distribution

  • Solstices and Equinoxes:

    • Solstice: December 21 (Southern Hemisphere summer) & June 21 (Northern Hemisphere summer).

    • Equinoxes: September 22 & March 20, equal day and night.

  • Seasonality at Different Latitudes:

    • Higher latitudes display greater variations in seasonal climate than lower latitudes.

Local Climate and Geography

  • Climate Patterns:

    • Horse latitudes have low precipitation, major deserts occur here.

    • Tropical region experiences significant and consistent precipitation.

  • Vertical Circulation of the Atmosphere:

    • Affects global wind patterns and resultant climate zones (Hadley cell, Ferrel cell, Polar cell).

Ocean Currents

  • Surface Currents: Warm and cool currents impacting global climate.

  • Upwelling:

    • Driven by wind, causes cool, nutrient-rich water to replace surface water.

Global Temperature Control

  • Temperature Influences:

    • Latitude, wind, ocean circulation, topography (elevation effects), and local geography.

Precipitation Patterns

  • Overall Trends:

    • Patterns driven by atmospheric circulation and topographic variations.

    • High precipitation near the equator, low in horse latitudes, deserts characterized by arid conditions.

Influences of Topography on Precipitation

  • Mechanism:

    • Air masses pick up moisture and release precipitation on windward slopes.

    • Leeward slopes experience dry conditions as descending air warms.

Continentality vs. Marine Climate

  • Continentality:

    • More extreme temperature variations; land heats and cools quickly.

  • Marine Climate:

    • More moderate temperatures; water's slow warming/cooling.

Marine Environment Characteristics

  • Physical Factors:

    • Oxygen variability, strong vertical gradients in temperature, light, nutrients, pressure.

    • Photic zones limit where photosynthetic organisms can survive.

Human Impact on Climate

  • Global Warming Trends:

    • Human activities have caused > 1.0°C warming since 1750.

    • 2025 global temperature averages recorded at 1.17°C above 20th century averages.

Climate Predictions

  • Future Projections:

    • Increased frequency and intensity of extreme weather events in coming decades.

Scientific Methodology

  • Steps of the Scientific Method:

    • Developing hypotheses, designing experiments, collecting data, publishing results.

Scientific Literature

  • Peer-reviewed Literature:

    • Ensures quality and accuracy of scientific communication.

  • Importance of Reading Scientific Literature:

    • Provides foundation for fields of study and insights into research methodologies.

How to Read a Scientific Paper

  • Structure of Scientific Papers:

    • Title, abstract, introduction, methods, results, discussion, literature cited.

  • Reading Tips:

    • Skim and annotate papers, focus on methods, results, and discussions.

Practical Applications

  • Example Study:

    • Pinsky et al. (2013) explored how marine taxa track local climate velocities.

    • Findings indicate that climate velocity can effectively explain distribution shifts across marine species, more so than species characteristics.

  • Key Takeaway: Differences in climate variables lead to varied distribution shifts in marine species, indicating a complex response to climate change.