10.1 Aquatic Biomes Temperature is not a limiting factor like it is on land because large amounts of water stabilize temperature. Rate of flow is the speed at which water moves. 70% of Earth is covered with water.      Organisms live in or on water.      Determined by depths and not locations.      Rivers are used for transportation, irrigation and as a source of electricity.

Characteristics of Aquatic Biomes    1. Amount of dissolved salts in the water (1 major characteristic).     2. Depth of water (another major characteristic).     3. Rate of flow of the water. 4. Amount of dissolved oxygen in the water.

Salinity ·    This is the basis of two groups of aquatic biomes. *saltwater (about 30 parts salt per 1000). *freshwater (about 0.5 parts salt per 1000).   The amount of dissolved salts in a sample of water. More salt in water than more buoyant. Hydrometers measure the buoyancy of water.

Salinity Oceans have more salts than the ponds and streams. Aquatic biomes that fall between streams (hardly any salt) and oceans (a lot of salt) are called brackish. Usually found where the ocean waters and the freshwater meet such as river deltas and coastal marshes.

Salinity The Great Salt Lake in Utah and Mono Lake in California are called hypersaline lakes and they are more saline than the ocean. These are exceptions.

Depth The ecosystem in a body of water depends on how much sunlight can penetrate the body of water. The amount of sunlight that reaches the bottom of the body of water control what kind of plant and animal life that can grow there.

Depth Zones Photic: the top layer of water that receives enough sunlight for photosynthesis. This zone is where most living organisms are found.

Depth Zones Aphotic zone: falls below the photic zone. Sunlight never reaches this zone.

Depth Zones Benthic zone: the mud floor of the body of water. Freshwater benthic animals include insect larvae, snails, catfish and turtles.In shallow lakes, plants can live here because the sun reaches here. Bacteria live on the ocean floor and nourish themselves with chemicals.

Human Impact Loss of aquatic habitats. Pollution of the water.