Biomes and Aquatic Ecosystems

                Biomes and Aquatic Ecosystems

Aim

  • Understanding what conditions characterize the world's biomes.

Elements of Life

  • Life can be created and sustained only in the presence of:

    • Moisture

    • Sunlight

    • Nutrients

Ecosystem Components

  • Organisms:

    • Insects

    • Algae

    • Fungi

    • Bacteria

    • Protozoans

    • Plankton

    • Termite mounds

    • Rotting logs

  • Environmental Factors:

    • Sunlight and heat

What is an Ecosystem?

  • Definition: An ecosystem is a community of living organisms (plants, animals, bacteria) and non-living components (air, water, soil, weather) that interact with each other as a system.

  • Interactions: Species interact in various ways, including competition and predation, contributing to the natural balance of the ecosystem.

  • Types: Ecosystems can be divided into aquatic and terrestrial categories.

What is a Biome?

  • Definition: Biomes are large ecological areas on the Earth's surface dominated by specific types of plants and animals.

  • Distinction: They can be differentiated by their resident organisms (forms of life) and climate conditions.

  • Adaptations: Organisms within a biome share specific adaptations suitable for that environment.

  • Influencing Factors: Climate is a significant determinant of the types of life found in a biome, influenced by factors such as:

    • Latitude

    • Geographic features

    • Atmospheric processes (heat and moisture)

Grouping of Biomes

  • A biome is defined as a grouping of ecosystems that have similar biotic and abiotic conditions.

  • Biotic Factors (Living):

    • Examples: Plants, Animals, Fungi, Bacteria

  • Abiotic Factors (Non-Living):

    • Examples: Water, Sunlight, Soil, Air, Temperature

World’s Major Biomes

  1. Tropical Forest

  2. Savanna

  3. Desert

  4. Temperate Rain Forest

  5. Grasslands

  6. Taiga

  7. Tundra

Tropical Forest

  • Location: Close to the equator (e.g. Myanmar, Fiji, Thailand, Philippines, Papua New Guinea, South & Central America, Vietnam, Brazil)

  • Climate: Year-round warm temperatures with more rainfall than any other biome.

  • Resources: Abundant soil, water, and heat.

Savanna

  • Location: Found in Africa, South America, and Australia.

  • Description: Transitional between forest and grassland, characterized by grasslands with clusters of trees.

  • Climate: Exhibits slight seasonal variation in temperature, with significant variation in rainfall and distinct rainy seasons.

Grasslands

  • Description: Moderate shortage of soil and water; adequate heat.

  • Rainfall: Moderate seasonal rainfall not sufficient to support larger plants and trees like a forest.

Desert

  • Description: The driest biome on Earth characterized by an extreme shortage of soil and water.

Taiga

  • Description: A forest located in cold, subarctic regions (Northern Hemisphere just south of the Arctic Circle); prevalent in Alaska, Canada, Scandinavia, and Siberia.

  • Climate: Moderate precipitation.

Tundra

  • Climate: Cold and damp, found on high-latitude landmasses, particularly above the Arctic Circle (e.g., Alaska, Canada, Russia, Greenland, Iceland) and some southern regions like Antarctica.

  • Characteristics:

    • Distinct lack of trees due to permafrost preventing root development.

    • Low precipitation restricts water availability.

    • Local fauna has adaptations:

    • Animals build up fat stores to sustain them through winter.

    • They have thick fur for insulation, and some hibernate or migrate during winter.

Chaparral

  • Description: A semi-arid landscape filled with a variety of shrubs and grasses densely packed together, often found in coastal regions.

  • Similarities: Shares some features with desert scrub biomes but has much more varied vegetation.

  • Locations: Found in regions like North America, Greece, Israel, Portugal, France, Italy, Southwest Australia, South Africa, Spain, Mexico, and Chile.

Aquatic Ecosystems

  • Aim: Understanding the conditions and organisms that characterize the world's aquatic ecosystems.

Classification of Aquatic Ecosystems

  • Ecologists classify aquatic ecosystems based on:

    1. Salinity

    2. Depth

    3. Water flow (whether it is flowing or standing)

Salinity

  • Definition: The amount of salts dissolved in the water.

    • Measurement: Sea-surface salinity is typically expressed in practical salinity units (PSU).

Depth

  • Importance: The depth of a body of water can affect:

    1. The amount of light available for photosynthesis.

    2. The temperature of the water.

Zones of Aquatic Ecosystems

  1. Photic Zone:

    • Description: The layer where enough sunlight penetrates for photosynthesis.

  2. Aphotic Zone:

    • Description: Located below the photic zone, where no sunlight can penetrate.

  3. Benthic Zone:

    • Description: The bottom layer of a body of water that may include habitats like oyster beds, seagrass meadows, and sandflats.

Flowing Water Systems

  • Definition: Bodies of water in constant motion, such as rivers and streams.

Standing Freshwater Ecosystems

  • Definition: Bodies of water that collect in depressions on Earth's surface.

  • Examples: Ponds, lakes, wetlands.

Characteristics of Standing Freshwater Ecosystems

  • Littoral Zone:

    1. Definition: Shallow and near-shore areas where aquatic plants can grow above the water surface.

  • Limnetic Zone:

    1. Definition: The open water zone farther from shore without rooted plants.

Wetlands

  • Description: Systems that combine elements of freshwater and dry land, rich in nutrients.

  • Examples: Marshes, swamps, bogs.

Flowing Freshwater Ecosystem Dynamics

  • Rivers and Streams:

    • Role: Rivers shape the landscape through which they flow.

    • Gravity: Water flows downhill due to the force of gravity.

Flood Plain

  • Definition: Areas near a river's course that flood periodically.

    • Example: The River Tay and its flat floodplain surrounding the main river channel.

Estuaries

  • Definition: Areas where land drainage meets oceans, home to diverse ecosystems.

  • Importance: Prevents soil erosion and flooding.

The Oceans

  • Structure: Oceans are divided into three zones:

    1. Intertidal Zone

    2. Neritic Zone

    3. Open Ocean

Intertidal Zone

  • Location: Where the ocean meets the land.

Neritic Zone

  • Definition: Extends from the low-tide mark to the continental shelf.

Open Ocean

  • Characteristics: Starts at the edge of the continental shelf and contains over 90% of Earth's ocean water.