Global Ecology pt 2

Role of Upwelling

  • Definition: Upwelling is the process where deep, cold, nutrient-rich water rises to the surface, replenishing nutrients in surface waters essential for marine life and fish populations.

  • Causes of Upwelling:

    • Coastal winds push surface waters away from the shore, creating space for deeper waters to rise.

    • Changes in ocean currents and temperature gradients can also trigger upwelling near coastlines.

  • Global Patterns Influencing Upwelling:

    • Wind patterns and the Coriolis effect enhance upwelling, while oceanic gyres affect nutrient distribution and marine productivity.

Seasons and Rain Shadows

  • Explanation of Seasons: The tilt of Earth's axis (about 23.5 degrees) causes varying angles of solar radiation, affecting temperatures and daylight throughout the year.

  • Rain Shadows: Formed when moist air ascends a mountain, cools, and precipitates on the windward side, leading to arid conditions on the leeward side.

El Niño

  • El Niño occurs when air pressure decreases in the eastern Pacific, causing warm surface water to accumulate, disrupting upwelling, and altering global climate patterns.

La Niña

  • La Niña is characterized by colder-than-average sea surface temperatures in the eastern Pacific, enhancing upwelling and increasing nutrients, leading to more robust marine ecosystems.

Earth’s Tilt

  • The axial tilt causes seasonal variations in day length, temperature, and solar radiation.

  • Equinox: Occurs biannually when day and night are equal in length.

  • Solstice: The Summer Solstice has the longest day in the Northern Hemisphere, and the Winter Solstice has the shortest day value.

Seasonal Changes

  • Solar energy distribution varies throughout the year, causing climate changes:

    • March 21-22 (Vernal Equinox): Equal solar energy in both hemispheres.

    • June 21-22 (Summer Solstice): Maximum solar energy in the Northern Hemisphere.

    • December 21-22 (Winter Solstice): Minimum solar energy in the Northern Hemisphere.

    • September 22-23 (Autumnal Equinox): Equal solar distribution again.

Airflow and Rainfall

  • Warm, moist air rises on the windward side, cooling to release moisture as precipitation. The leeward side experiences a rain shadow effect, resulting in dry conditions.

Temperature Variation with Elevation

  • A 1000-meter increase in elevation generally drops temperature by about 6 degrees Celsius.

  • Sunlight Exposure: South-facing slopes receive more sunlight than north-facing slopes in the Northern Hemisphere, making them warmer and more suitable for plant growth.

Biomes Overview

  • Definition of Biomes: Major life zones classify aquatic and terrestrial habitats by physical characteristics like climate, soil type, and dominant species.

  • Aquatic Biomes: Classified by depth and substrate.

  • Terrestrial Biomes: Classified by dominant vegetation, influenced by latitude and precipitation.

Major Biomes

  • Examples:

    • Tropical Forest

    • Temperate Grassland

    • Desert

    • Temperate Broadleaf Forest

    • Northern Coniferous Forest

    • Arctic and Alpine Tundra

  • Climate Graphs: Illustrate relationships between annual mean temperature and precipitation for various biomes.

Upwelling and Nutrient Availability

  • Upwelling is critical for nutrient availability, bringing nutrients from the sea floor to phytoplankton, essential for marine food webs and healthy fisheries.

Practice Free Response Question

  • Critical Thinking Engagement: Prepare to discuss:

    • Role of Upwelling: How it makes nutrients accessible to primary producers.

    • Impact on Marine Life: Increased productivity leads to higher biodiversity and healthier fish populations.

    • Seasonal Variations: Effects of climatic changes such as El Niño and La Niña on nutrient cycling.

    • Ecosystem Services: Importance of upwelling regions for carbon cycling and fisheries.

  • Bring prepared insights to the Bio 142 Q&A session for further discussion and feedback.