APES Outline: Module 1.3

Oceans constitute 97.22\% of all water (salt water).
Fresh water is only 2.78\% of all water.
Of total fresh water: ice and glaciers 77.28\%, groundwater 22.22\%, surface water 0.47\%, atmospheric water 0.03\%.
Less than 1\% of Earth's water is accessible for human use.

Characterized by flowing fresh water, originating from springs or runoff.
Streams are typically narrow; rivers are wider.
Fast-moving sections (rapids) have high dissolved oxygen, supporting fish like trout and salmon.
Slower-moving sections have lower dissolved oxygen, favoring species like catfish.
Threats: Excess nutrients and pollutants.

Contain standing water; defined by depth too great for emergent vegetation in some areas.
Lakes are larger than ponds.
Lake Zones:
- Littoral zone: Shallow, near-shore with rooted/emergent plants; high photosynthesis.
- Limnetic zone: Open water, sunlight penetrates, dominated by floating algae (phytoplankton).
- Profundal zone: Deep water, no sunlight, no photosynthesis; bacteria decompose detritus, consuming oxygen.
- Benthic zone: The muddy bottom sediment.
Fertility Classification:
- Oligotrophic lakes: Low nutrients, low phytoplankton, very clear water.
- Mesotrophic lakes: Moderate fertility.
- Eutrophic lakes: High fertility, high algae concentration, turbid water.

Submerged or saturated by water for part of the year, shallow enough for emergent vegetation.
Highly productive biomes.
Types: Swamps (emergent trees), Marshes (nonwoody vegetation), Bogs (acidic, sphagnum moss dominate).
Services: Reduce floods, filter pollutants, recharge groundwater, provide critical habitat.
Threats: Drainage for agriculture/development, pollution.

Estuaries: Areas where rivers (freshwater) meet oceans (salt water); highly productive due to nutrient input; filter contaminants.
Salt Marshes: Found in temperate estuaries; nonwoody emergent vegetation; vital spawning grounds for fish/shellfish.
Threats: Habitat loss due to development and pollution.

Occur along tropical/subtropical coasts; contain salt-tolerant trees with submerged roots.
Protect coastlines from erosion, provide habitat for marine organisms.
Threats: Destruction for human habitation or agriculture.

Narrow band of coastline between high and low tide levels.
Organisms face harsh, fluctuating conditions (exposure to air, temperature extremes, desiccation, strong waves).
Threats: Pollution (trash, chemicals, oil spills).

Warm, shallow waters in tropical regions; Earth's most diverse marine biome.
Formed by tiny animals (corals) secreting limestone skeletons, living in colonies.
Mutualistic relationship with algae (algae photosynthesize, providing energy to corals).
Corals require sunlight for algae, hence found in shallow water.
Threats: Pollutants, sediments, coral bleaching (algae die, causing corals to turn white, due to disease, low ocean pH, high temperatures).

Deep ocean water away from the shoreline.
Ocean Zones:
- Photic zone: Upper layer, sufficient sunlight for photosynthesis by algae (major oxygen producers).
- Aphotic zone: Deeper layer, no sunlight; chemosynthesis by bacteria (using methane/hydrogen sulfide) forms the base of a unique food web. Many organisms generate light.
- Benthic zone: The ocean floor.

Water on Earth

Most water (97.22\%) is salty, found in oceans.
Only 2.78\% is fresh water.
Of this fresh water:
- 77.28\% is locked in ice and glaciers.
- 22.22\% is groundwater.
- 0.47\% is surface water (like lakes and rivers).
- 0.03\% is in the atmosphere.
Less than 1\% of all Earth's water is easy for humans to use.

How Aquatic Biomes Are Grouped

They are grouped by things like how salty they are, how deep they are, and how much the water moves.
Two main types are Freshwater (not much salt) and Marine (very salty).

Freshwater Biomes

Streams and Rivers

Lakes and Ponds

These have still water. They are deep enough in some spots that plants don't grow all the way across.
Lakes are bigger than ponds.
Parts of a Lake:
- Littoral zone: Shallow area near the shore with plants rooted in the bottom. Lots of sunlight and growth here.
- Limnetic zone: Open, sunny water where tiny floating plants (algae) grow.
- Profundal zone: Deep, dark water where no sunlight reaches, so no plants grow. Bacteria here break down dead stuff and use up oxygen.
- Benthic zone: The muddy bottom.
Lake Health (Fertility):
- Oligotrophic lakes: Have few nutrients, few algae, and very clear water.
- Mesotrophic lakes: Have a medium amount of nutrients.
- Eutrophic lakes: Have many nutrients, lots of algae, and cloudy water.

Freshwater Wetlands

These areas are covered or soaked with water for part of the year and are shallow enough for tall plants to grow.
They are very active places for life.
Types:
- Swamps have emergent trees.
- Marshes have nonwoody plants.
- Bogs are acidic and covered mostly by sphagnum moss.
Helpful things they do: Stop floods, clean up pollution, refill underground water, and provide homes for many animals.
Problem: Drained for farms/buildings, pollution.

Marine Biomes

Estuaries and Salt Marshes

Estuaries: Where rivers (freshwater) meet oceans (salt water). They are very lively because of all the nutrients and they help filter dirty water.
Salt Marshes: Found in mild climate estuaries; have nonwoody plants. They are crucial spots for young fish and shellfish to grow.
Problem: Lost to building and pollution.

Mangrove Swamps

Found along warm tropical and subtropical coasts. They have salt-loving trees with roots in the water.
They protect shorelines from erosion and provide homes for sea creatures.
Problem: Destroyed for homes or farms.

Intertidal Zones

This is the small strip of coastline between high and low tide.
Creatures here have to deal with tough, changing conditions (being out of water, extreme heat/cold, drying out, strong waves).
Problem: Pollution (trash, chemicals, oil).

Coral Reefs

Found in warm, shallow, tropical waters. They have the most diverse life in the ocean.
Built by tiny animals called corals that make limestone skeletons and live in groups.
Corals have a partnership with algae (algae make food from sunlight, giving energy to corals).
Corals need sunlight for their algae, so they live in shallow water.
Problem: Pollution, dirt, coral bleaching (algae die off, making corals white, due to sickness, too much acid in the ocean, or high temperatures).

Open Ocean

This is the deep ocean water far from land.
Ocean Layers:
- Photic zone: Top layer where sunlight reaches, allowing algae to make food (and most of Earth's oxygen).
- Aphotic zone: Deeper layer where no sunlight reaches. Some bacteria here make food using chemicals (like methane) instead of sunlight. Many animals here make their own light.
- Benthic zone: The very bottom of the ocean.