Aquatic Ecosystems Overview

Aquatic Ecosystem Types

• Aquatic ecosystems are categorized by salinity: freshwater and marine.
• Freshwater includes ponds, lakes, streams, and wetlands.
• Wetlands are periodically underwater or have high soil moisture.
• Factors like temperature, light, oxygen, and nutrients determine habitat suitability.

Freshwater Ecosystem Components

• Plankton: Microscopic organisms (phytoplankton, zooplankton) that float freely.
• Nekton: Active swimmers (fish, turtles) independent of currents.
• Benthos: Bottom-dwelling organisms (clams, insects).
• Decomposers: Organisms breaking down organic matter.

Lake and Pond Structure

• Lakes and ponds can be structured into horizontal and vertical zones.
• Littoral zone: Shallow, light-penetrating zone with abundant plant and animal life.
• Benthic zone: Bottom region inhabited by decomposers and other bottom-dwelling organisms.
• Eutrophication: Increased nutrients (e.g., nitrates) leading to excessive plant growth and oxygen depletion, harming other organisms.
• Eutrophic lake: A lake with significant plant growth due to excessive nutrients.

Freshwater Wetlands

• Freshwater wetlands are periodically flooded areas.
• Marches: Dominated by non-woody plants, often in low, flat areas, with little water movement.
• Swamps: Dominated by woody plants (trees, shrubs).
• Occur on flat, poorly drained lands, often near streams.
• Various marsh types exist based on salinity (brackish, salt marsh).
• Benthic zones rich in nutrients, plants, decomposers, and scavengers.
• Found in the southeastern U.S., such as the Florida Everglades.

River Pollution

• Rivers are polluted through industrial waste, sewage, and garbage disposal.
• Runoff (pesticides, poisons, sediments) is a major source of pollution.
• River pollution can kill organisms and make fish inedible.

Marine Ecosystem Components

• Coastal areas: Organisms adapt to changing water levels and salinity.
• Open ocean: Organisms adapt to temperature, light, and nutrient variations.
• Coastal wetlands: Land areas covered by saltwater periodically.
• Estuaries: Where freshwater mixes with saltwater (mineral-rich mud).
• Coral reefs: Limestone ridges in tropical climates, composed of coral fragments.
• Salt marshes: Maritime areas with salt-tolerant grasses, sedges.
• Mangrove swamps: Tropical/subtropical swamps with mangrove trees.
• Barrier Islands: Long ridges of sand parallel to the shore.

Marine Ecosystem Threats

• Pollution: Oil spills, sewage, pesticides, and silt runoff pollute marine ecosystems.
• Overfishing: Depletes fish populations and disrupts the ecosystem balance.
• Destructive fishing practices: Damage to coral reefs; entanglement of marine mammals.
• Ocean pollution sources: Runoff from farms and industries, and sewage discharge.

This quiz explores the types and components of aquatic ecosystems, focusing on freshwater environments such as lakes and ponds. Learn about the various organisms, their roles, and the structure of these vital habitats. Test your knowledge on factors that influence aquatic ecosystems.