Climate and Ecosystem Dynamics

Habitat Diversity

• Sunlight intensity varies geographically, highest at the equator.
• Positive feedback loop exists between ice, water, and temperature: ice reflects less sunlight, melting and warming.
• Snow is highly reflective, while melted water is less so.
• Water has high heat capacity; oceans have stable temperatures, unlike land.
• Earth's net heat gain is at the equator and loss at the poles; wind and currents distribute energy.
• Asian monsoons are driven by Himalayan and Tibetan Plateau formation: summer heat causes air to rise, bringing winds, and winter cold causes air to move toward the ocean.
• Currents reverse seasonally.
• Atmospheric circulation (Hadley cells).
• Higher moisture levels correlate with taller trees.

Coriolis Effect and Wind

• Earth's rotation causes wind currents to curve (right in the Northern Hemisphere, left in the Southern).
• Trade winds are a result.
• Major wind patterns are explained by combining the Coriolis effect and Hadley cells.
• Three atmospheric circulation patterns: high evaporation/low rainfall (deserts), high rainfall/low evaporation (rainforests), or seasonal variation.
• Mountains affect precipitation: windward sides receive more rain, leeward sides are typically dry.

Ocean Currents

• Wind drives ocean currents.
• Water density is determined by temperature and salinity.
• Equator has higher salinity, 30 degrees latitude has lower.
• Atlantic is saltier than Pacific.
• Ekman spiral describes how wind affects multiple water layers, causing movement at a 90-degree angle to the wind direction (right in the N.H.).
• Ocean gyres are circular current systems, moving warm water north and cold water south (important for Europe's climate).
• Monsoonal systems are exceptions, with current reversals.

Thermohaline Circulation

• Thermohaline circulation is the deep ocean circulation of water and nutrients (surface flow, sinking, spreading).
• It takes centuries for the movement to occur throughout the oceans.
• Nutrient concentration increases with depth, while oxygen decreases.
• Pacific is the most nutrient-rich ocean.
• Pycnocline is the boundary between dense and less dense water layers.

Sound in Water

• Sound travels faster in warmer water and higher pressure.
• Sound speed in water accounts for temperature and pressure.
• SOFAR channels amplify sound.

Causes of Nutrient Distribution

• Diffusion (slow)
• Double diffusion (salt fingers) is much faster than molecular diffusion.
• Wind and wave mixing causes Langmuir circulation cells.

Ocean Waves and Mixing

• Internal waves exist between water layers of differing densities.
• Internal waves breaking release nutrients and impact shelves.
• Tidal mixing occurs along coastlines.
• Island wakes and turbulence stir nutrient mixing.
• Convective mixing is reduced in areas with strong thermocline layers.

Eddy Formation

• Cyclonic eddies circulate clockwise in the N.H. and bring upwelling.
• Warm-core eddies circulate counter-clockwise in the N.H.
• Eddy longevity determines nutrient upwelling's impact.
• Eddies can affect hurricane formation.

Benthic Regeneration and Nutrient Upwelling

• Benthic regeneration in shallow waters leads to higher nutrient levels.
• Hurricanes can bring nutrients to surface waters from the ocean bottom.

Climate Variability

• North Atlantic Oscillation (N.A.O) influences seasonal weather variability.
• Ocean temperature trends have a general upward trend, but yearly variability can mask significant change.

Plant Biomass

• Land plants have significantly higher biomass than marine plants.

Antiherbivore Devices

• Land plants use size for defense (large enough for toxins).
• Ocean plants reproduce rapidly, lacking time for elaborate defenses.

Ecological Niches

• Species occupy a niche hyperspace (n-dimensional).
• Fundamental niche is the theoretical niche where a species can live, while the realized niche is where it actually lives.

Fitness

• Fitness is the ability to pass genes via reproduction.
• Components of fitness include survival, reproduction, modes and frequency of reproduction, offspring number, and physiological health.

Reproduction Modes

• Binary fission, cloning, and sexual reproduction are common in different organisms.

Life Cycles and Stages

• Unicellular and multicellular organisms reproduce by various means like binary fission, budding, and zygote-to-adult stages.
• Some organisms exhibit metamorphosis and molting stages to adapt.

Environmental Factors and Adaptations

• Adaptations are the responses to environmental pressures; responses may or may not enhance fitness.
• Ecological adaptations may be molecular, biochemical, physiological, morphological or behavioral.

Genetic Variation and Differentiation

• Genetic variation facilitates adaptation to environmental change.
• Genetic differentiation occurs when populations are geographically separated.
• Genetic clines occur by natural selection through environmental gradients, without barriers.

Constraints on Natural Selection

• Time, gene flow, and adaptive landscape are constrains on natural selection.

Coevolution

• Prey and predator can adapt to each other simultaneously.

Time and Space Scales of Environmental Changes

• Environmental factors vary in magnitude, extremes, duration, frequency, and rate.
• Time scale variations include rapid fluctuations, seasonal, decadal, and long-term factors with different adaptation effects.
• Space scales include gradients, patches, and microtopography.

Abiotic Factors - Water Needs

• Water is a critical abiotic factor.
• Osmosis, transpiration, and excretion are important water processes.

Osmosis and Osmoregulation

• Osmoconformers maintain their internal salt concentration similar to the environment; use organic compounds.
• Osmoregulators maintain constant internal salt concentration by pumping salts and water in or regulating water intake.
• Different strategies are associated with different aquatic environments (marine, freshwater, brackish).