Aquatic Biomes

The Basics Nearly 75% of Earth’s surface is covered in water and includes streams, marshes, lakes, and oceans. All of these are governed by biotic and abiotic factors, including light, nutrient availability, and oxygen. Include freshwater ecosystems, estuaries, and marine ecosystems.

Freshwater Ecosystems Only 3% of surface water is freshwater. 2% of this is ice. There are two main types of freshwater ecosystems. 1. Flowing H2O 2. Standing H2O

Flowing-Water Ecosystems Includes: rivers, streams, creeks, and brooks Organisms that live here are well-adapted to the rate of flow (larvae with hooks, catfish suckers, streamlined fishes, etc.)

Standing-Water Ecosystems Includes: lakes and ponds Provides habitats for plankton (tiny, free-floating organisms) Phytoplankton (plant-like) form base of many aquatic food webs Zooplankton (animal-like) feed on the phytoplankton

Plankton

Other Freshwater Ecosystems Wetlands: water either covers the soil or is present at or near the surface of the soil for at least part of the year. Water may be flowing or standing and can be fresh, salty, or brackish Serves as a breeding ground for insects, fishes, and other aquatic animals, amphibians, and migratory birds.

Wetlands

Three Types of Wetlands Bogs Dominated by sphagnum moss Form in depressions where water collects Acidic water

Three Types of Wetlands Marshes Shallow wetlands along rivers May be underwater for all or part of the year Contains cattails, rushes, and other tall grass-like plants

Three Types of Wetlands Swamps Water flows slowly through these “flooded forests” Presence of trees & shrubs distinguish a swamp from a marsh

Swamps

Estuaries Formed where rivers meet oceans Many are shallow (photosynthesis occurs through entire depth) The primary producers here are: plants, algae, and photosynthetic and chemosynthetic bacteria Contain fewer species than freshwater or marine ecosystems, but contain a lot of biomass

Estuaries Serve as spawning/nursery grounds for commercially important fishes, shrimps, and crabs Many young animals feed and grow in estuaries, head out to sea to mature, then return to reproduce Waterfowl use estuaries for nesting, feed and resting during migrations

Estuaries

Types of Estuaries Salt marshes Temperate-zone estuaries, mostly salt-tolerant grasses Found along eastern coast of USA from Maine to Georgia

Types of Estuaries Mangrove swamps Widespread across subtropical and tropical regions like southern Florida and Hawaii Mangrove trees (salt-tolerant) and seagrasses reside here.

Mangroves

Mangroves

Mangroves

Marine Ecosystems Photosynthesis is limited only to the photic zone (down to a depth of about 200 meters); Only algae and other producers grow here

Marine Ecosystems Below the photic zone is the aphotic zone Permanently dark Chemosynthetic autotrophs are the only producers in this zone

Marine Ecosystems Are divided into zones based on their depth and distance from shore. These zones are: Intertidal Zone Coastal Ocean Zone Open Ocean Zone The benthic zone covers the ocean floor and is not exclusive to any of the other marine zones.

Draw the picture on page 109 Label: land, intertidal zone, coastal ocean, open ocean, benthic zone, photic zone, aphotic zone, and depths (in meters)

The Intertidal Zone Exposed to regular but extreme changes Air Wave action Temperature change Currents Barnacles cling to rocks

Coastal Oceans Extends from the low-tide mark to the outer edge of the continental shelf Photosynthesis occurs throughout this depth Rich in plankton and many other organisms; still in the photic zone.

Coastal Oceans The most productive coastal ocean community is the kelp forest found along California and the Pacific Northwest

Coastal Oceans Coral reefs are found here Among the most diverse & productive environments on Earth Built on calcium chloride skeletons

Open Oceans Begin at the edge of the continental shelf The largest zone (marine zone), covering 90% of ocean surface area

Open Oceans Organisms are exposed to high pressure, extreme cold, and total darkness Low levels of nutrients

Benthic Zone Lives attached to or near bottom of the ocean. Anemones, marine worms, sea cucumbers, and clams all live here

Benthic Zone Benthos do not move much. They feed on detritus that filters down from the surface Near deep sea vents: chemosynthetic producers that derive energy from sulfur