Chapter 10:Freshwater Biomes

Freshwater is less than 3% of the Hydrosphere. 90% of the freshwater is locked beneath the Earth’s

surface. Water is cycled through evaporation and transpiration

from the atmosphere to the land and back again.

10.1 Aquatic Biomes Land biomes cover

less than 30% of the Earth’s surface.

Aquatic biomes contains organisms that live in water.

Two factors that are used to classify aquatic biomes: 1. The amount of salt in

the water - salinity 2. The depth of the

water and the amount of sunlight that reaches it

10.1 Aquatic BiomesSalinity – the amount of

dissolved salts in a sample of water

Salinity is measured in parts per thousand (ppt)

Aquatic biomes are divided into two groups: saltwater and freshwater

Saltwater biomes have 30 ppt – (oceans, seas)

Freshwater biomes have 0.5 or less ppt (lakes, ponds, rivers)

10.1 Aquatic Biomes Brackish water is more

salty that fresh but less than the ocean – (anywhere freshwater meets with sea water – marshes, deltas, estuaries)

Hypersaline – more salt than the ocean - 40 ppt (the Great Salt Lake –Utah and Mono Lake – California)

10.1 Aquatic BiomesDepthAvailable sunlight is

the determining factor for water depth.

Sunlight amount determines types of plants that can grow

Producers are the base of all aquatic food webs

10.1 Aquatic BiomesDepth - Three layers:Photic zone – top

layer of water gets enough sunlight for photosynthesis to about (100 m in open ocean)

Aphotic zone – sunlight never reaches this zone (only deep lakes and ocean)

Benthic zone – the floor of a body of water.

10.2 Freshwater EcosystemsFreshwater biomes

divided into TWO classifications:

Standing-water – lakes, ponds, bogs swamps, marshes. Water does not move in and out but does move within the system.

Flowing-water – Rivers, streams. Water moves in, out and through the system

10.2 Standing-Water BiomesUpper level – warm, gets

most sunlight. Contains plankton – microorganisms that float on the surface of the water.

Phytoplankton – perform photosynthesis, make their own food (producers)

Zooplankton – cannot perform photosynthesis, eat phytoplankton (consumers)

10.2 Standing-Water BiomesBenthic level – cool,

gets little or no sunlight. Contains scavengers that consume dead organisms.

Food Chain: Small fish eat plankton and insects, larger fish eat small fish.

10.2 Standing-Water Biomes

WETLANDS Found where water and

land meet. Roots of plants are under

water part or all of the year.

Soils are soaked with water.

Water can be fresh or brackish

10.2 Standing-Water Biomes Wetlands act as water

filters - remove chemicals from water as it passes through them.

Can be used as treatment for waste water.

Important breeding, feeding and resting areas for migrating birds.

Wetlands protect areas from flooding.

Refill aquifers

10.2 Florida Everglades Once covered the entire

lower part of Florida from Lake Okeechobee to the Keys.

Area reduced through human activity (draining) from over 150 miles to just 1,508,537.9 acres

10.2 Everglades Home to many rare and

unusual organisms: Alligator Florida panther Florida soft-shelled turtle Key deer Great Blue Heron Ibis Florida Tree Snail

10.3 Flowing-Water EcosystemsFlowing-water

ecosystems all have water that moves over land.

All water that moves above ground are streams

All water that move underground are aquifers

10.3 Flowing-Water EcosystemsSTREAMS Begin at high altitude, as

runoff from melting snow on mountain tops

Gravity causes water to move downhill

Stream beginnings are called the “origin” or “head”

Water from the starting place is called headwaters

The water is cold and carries much material with it – called sediments

10.3 Flowing-Water Ecosystems Sediments are small

particles that settle to the bottom of any body of water

Provide nutrients and place for plant roots to grow

Increases in producers bring increases of consumers

Sedimentation (sediment collecting) and soil erosion cause streams/rivers to change course - become more and more winding