Aquatic Ecosystems

Introduction Ecosystem - collection of all organisms living within their environment. Aquatic ecosystems: centered around water and the organisms who inhabit these ecosystems are specifically adapted for such survival.

The Hydrosphere The Earth is divided into different spheres. Hydrosphere: relates to the entire mass of water on the planet. Biosphere: includes all living things; including life on land, in water, and in air. The organisms within the biosphere interact closely with the hydrosphere for survival.

Streams and Rivers A river is a stream of moving water that follows a definite course. Creek, brook, stream, and river quality is directly related to the health of other bodies of water, as these moving bodies of water drain into larger lakes and some eventually lead to oceans. These environments are characterized by higher levels of oxygen (due to the waters movement) and little plant life until the speed of the river slows.

Streams and Rivers Recent EPA findings (summarized below) show that the health of the nations streams is poor polluted with phosphorous and nitrogen with nearby land disturbed by pipes, pastures, or pavement.

Freshwater Lakes & Ponds A lake is a body of water of considerable size surrounded by land. The EPA states that freshwater inland lakes and reservoirs provide our nation with 70% of its drinking water and supply water for industry, irrigation, and hydropower. Lake ecosystems support complex food web interactions and provide habitat for threatened and endangered species. The United States has a 19 billion dollar freshwater fishing industry dependent on the health of lakes, and many states’ tourism industry centers rely on these freshwater reservoirs. Video – Cleaning Lake Tahoe

Wetlands Wetlands are characterized by regular saturation of the soil; either totally covering the soil or is present at or near the surface for at least part of the year. They are found on every continent except Antarctica. They can include swamps, bogs, and marshes and can be fresh, salty or brackish (a mixture of fresh and salt water). (Video - Wetland Conservation) http://www.tpwd.state.tx.us/learning/webcasts/seacenter/images/txhab/wet-types.jpg

Estuary Wetlands formed where rivers meet the sea are known as estuaries, a combination of fresh and salt water (brackish water). A delta is the fanned build up of sediment from river deposits which often covers the center of the estuary. http://www.texasep.org/assets/images/estuary2.GIF

Relationships Between Pollutants & Aquatic Environments http://www.epa.gov/owow/oceans/nccr3/pdf/nccr3_entire.pdf

Marshes Marshes - wetlands frequently or continually flooded with water, with soft-stemmed vegetation. Can be fresh or salt water. Nutrients are plentiful leading to an abundance of plant and animal life. Marshes recharge groundwater supplies, help to limit damage from flooding and coastal storms, and most importantly, clean the water of pollutants. As water moves slowly through a marsh, sediment and other pollutants settle to the floor of the marsh.

Swamps Swamps are wetlands characterized by woody plants with water soaked soils during the growing seasons and standing water at times. The soils are thick, black, nutrient-rich and grow water-tolerant trees such as Cypress, Atlantic White Cedar, and Tupelo. http://www.nwrc.usgs.gov/factshts/2004-3019/images/figure4.gif Plants, birds, fish, and invertebrates such as freshwater shrimp, crayfish, and clams require the habitats provided by swamps. Many rare species, such as the endangered American Crocodile depend on these ecosystems as well. (Video – American Crocodiles)

Texas Swamps Caddo Lake State Park the only natural lake in Texas created by a mass of trees and flood debris known historically as the Great Raft of the Red River. It obstructed the river channel for more than 100 miles above Shreveport, Louisiana until 1874, when it was successfully removed to clear the channel for navigation. lake slowly drained away, leaving a swamp - A modern dam has recreated the lake

Mangrove Swamps Characterized by salt-tolerant evergreen trees protect coastlines from erosion, filter pollutants from the water and are home and food for a variety of organisms. Some have aerial roots that collect oxygen not available in the mud. Some excrete salt in their leaves. Ex: The famous Florida Everglades (Video – Save the Everglades) http://www.fao.org/forestry/4185-1-0.jpg

Seagrass Beds Another source of food and protection for aquatic organisms living near the coast fully marine flowering plants grow best in shallow bays and lagoons very susceptible to pollution important food source for aquatic turtles, manatees, dugongs, and other marine herbivores Salt Marsh Video http://baysoundings.com/Spring08/Stories-Images/Seagrass-Graph-black_white.jpg http://www.thalabeach.com.au/blog/wp-content/uploads/2009/10/dugong.jpg

Kelp Forest common name for brown seaweed, a type of algae that is photosynthetic Kelp forests grows in cold water and certain species can grow to reach 265+ feet! gas floats on the surface, allowing access to sunlight Unlike seagrass, kelp does not have root systems Photograph by Frans Lanting

Lagoons & Fjords Fjords - deep, sheltered seas created by ancient, glacial erosion, often bordered by steep cliffs Lagoons - partially enclosed body of sea water Both areas are characterized by slower moving waters protected from the strong currents of the coast.