1. Ecology Notes September 9, 2015
Aquatic Ecosystems
Ecology Notes
September 9, 2015

2. Conditions Underwater
Water Depth
Sunlight only penetrates a short distance through the water.
Photic Zone: sunlit region, near surface, photosynthesis occurs.
Aphotic Zone: dark region, no photosynthesis, chemosynthesis occurs.
Benthic Zone: rocks and sediments on bottom of lakes, rivers or oceans.
Temperature and Currents
Warmer water near equator; colder water near the poles.
Deepest parts of water are colder than the surface.
Currents can carry water that is significantly warmer or cooler than would by typical for any given latitude, depth or distance from shore.
Nutrient Availability: type and availability of nutrients varies between bodies of water, which affects the type of organisms that can survive there.

3. Freshwater Ecosystems Only 3% of Earth’s surface water is fresh water, but it provides terrestrial organisms with drinking water, food, and transportation.
Rivers and Streams
Originate from underground water sources in mountains.
Near source, high amount of dissolved water.
Downstream, sediments build up and plants establish themselves.
Lakes and Ponds
Food webs based on plankton (phytoplankton and zooplankton) and attached algae/plants.
Water flows in and out of lakes and circulates between surface and the benthos.
Freshwater Wetland
Wetland: water either covers the soil or is present at or near the surface for at least part of the year.
Nutrient-rich, highly productive, purify water, prevent flooding, and may serve as breeding ground.

4. Estuaries
Estuaries: a special kind of wetland, formed where a river meets the sea.
Contain mixture of fresh and salt water.
Many are shallow.
Serves are spawning and nursery grounds for many ecologically and commercially fist and shellfish species.
Salt marsh: temperate estuaries characterized by salt-tolerant grasses above the low-tide line and seagrasses below water.
Mangrove swamp: tropical estuaries characterized by several species of salt-tolerant trees.
Chesapeake Bay
Everglades National Park

5. Marine Ecosystems Intertidal Zone Coastal Ocean Open Ocean
Organisms are submerged at high tide and exposed to air and sunlight at low tide.
Organisms subjected to regular and extreme changes in temperature.
Organisms often battered by waves and currents.
Coastal Ocean
Extends from low-tide mark to the outer edge of the continental shelf.
Water received a lot of sunlight and nutrients.
Open Ocean
Begins at the edge of the continental shelf and extends outward.
90% of the world’s ocean.