Aquatic Ecosystems Lesson 4.4 Bodega Head, Sonoma Coast M. Parker

Freshwater: flowing Freshwater = 3% of all surface water on earth Flowing systems include rivers, streams, creeks Supports a large variety of fishes, reptiles and amphibians, as well as their predators, such as otters, bears, eagles and raccoons. Water flow is too fast to support most invertebrate life.

Fresh water: standing Lakes and ponds are the most common standing water ecosystems Water circulates within as well as in and out of the system (little currents) This helps to distribute oxygen, nutrients and heat through the system Habitat for “plankton,” or tiny, free-floating organisms “Phytoplankton” are single-celled algae “Zooplankton” are microscopic animals that feed mainly on the phytoplankton

Wetlands Water covers soil or is present at least part of year Can be fresh water, salty or “brackish,” which is a mixture of fresh and salt water (Shollenberger) Very productive ecosystems, many plant and animal species supported (over 170 spp of birds alone at Shollenberger Park) Over 90% of SF Bay wetlands gone due to development and agriculture 165 acres of tidal wetlands, brackish water from Petaluma river, but also fresh water channels– different communities of plants and animals. Over 160 species of birds have been identified here. Shollenberger Park, Petaluma

SF Bay wetlands 150 years ago and today Bay Institute

Estuaries Wetlands formed where rivers meet the sea. Mixture of fresh and salt water, affected by rise and fall of ocean tides Many shallow, enough light for photosynthesis, so lots of plant life in estuaries Most plant material is not consumed by zooplankton, but forms “detritus,” tiny particles that provide food for bottom of the food web such as clams, sponges, and worms. Breeding grounds for many fish And shellfish that we eat

Continental slope and continental rise Marine Ecosystems Photic zone Land 200 m 1,000 m Intertidal zone Coastal ocean Open ocean 4,000 m Aphotic zone Benthic zone 6,000 m The ocean can be divided into zones based on light penetration and into zones based on depth and the distance from shore. Each zone contains a characteristic assemblage of organisms. Ocean trench Continental slope and continental rise 10,000 m Continental shelf Abyssal plain

Oceans can be divided into zones based on amount of light, depth and distance from shore. Photosynthesis is limited to “Photic” zone (200 meters deep) “Aphotic” zone below is permanently dark and cold. Chemosynthetic organisms are The only producers that can live in aphotic zone. They get their energy from chemicals leaked from deep sea vents in the ocean floor. However, many different consumers, such as octopuses and giant squid can live in the deep ocean.

Rocky Intertidal Intertidal organisms are exposed to regular and extreme changes in their environment Once or twice a day, submerged in water at high tide At low tides, exposed to sunlight, air and temperature changes, wave shock Competition leads to “zones” of different organisms living in particular habitats

Coastal ocean Extends from low tide mark to outer edge of continental shelf Shallow enough for photosynthesis Rich in plankton and many other organisms Kelp = giant brown algae that can grow 50 cm/day! Kelp forests provide habitat for snails, sea urchins, sea otters, many fish species, seals, even whales.

Kelp forest at Monterey Bay Aquarium

Coral reefs Found in warm, shallow tropical coastal oceans Among the most diverse and productive systems on earth Named for tiny coral animals that have hard calcium carbonate skeletons. Live together in vast numbers and feed on plankton with tentacles Live symbiotically with algae in their tissues. Algae do photosynthesis and use coral waste as nutrients. Algae also provide corals with carbon compounds for growth.

Open ocean Largest marine zone, over 90% of the surface area of the world’s oceans. 500 meters deep to 11,000 meters in the deepest ocean trench Deep ocean creatures are subjected to high pressure, frigid temperatures and total darkness Fishes of all types dominate, but also many marine mammals, jellies, octopus, etc.