Chapter 7 Aquatic Ecosystems Environmental Science Spring 2011

Chapter 7.2 Marine Ecosystems

Contain salt water Found in and around world’s oceans Amount of sunlight and nutrients vary from area to area

Costal Wetland Costal Wetland: areas covered by salt water for all or part of the time Provide habitat and nesting areas for many fish and wildlife Absorb excess rain, protects from flooding, act as filter

Estuaries Estuaries: area in which fresh water from a river mixes with salt water from the ocean Waters meet: currents form and cause mineral-rich mud and dissolved nutrients to fall to the bottom – Make a nutrient trap

Estuaries Plants and Animals – Many organisms depend on estuaries for spawning – Have plenty of light and nutrients therefore support many organisms – Organisms able to tolerate variations of salinity

Estuaries Threats: – Often used as waste landfills – Pollution has been damaging – Often used as harbors

Salt Marshes Salt Marshes: areas where rivers deposit their load of mineral rich mud – Support community of clams, fish, aquatic birds – Acts as nursery for many species where they find protection when they are small and then move on to ocean

Mangrove Swamps Mangrove Swamps: several species of small trees adapted for growing in shallow salt water – Most mangroves have wide, above-ground roots for support – Found in tropical and subtropical zones – Protect coastline from erosion and reduce damage from storms – Pollution and land fills are a threat

Rocky and Sandy Shores Rocky shores have more plant and animal species than sandy shores Animals adapted to effects of drying and exposure to low tide Barrier Islands: often run parallel to sandy shores – Help to protect the mainland and the coastal wetlands form storms and ocean waves

Coral Reefs Coral Reefs: limestone ridges built by tiny coral animals called coral polyps and the algae that live inside them

Coral Reefs Coral polyps: secrete skeletons of limestone (calcium carbonate), which slowly accumulate and form coral reefs Thousands of plant and animal species live here  among most diverse ecosystems

Coral Reefs Corals live only in warm salty water where there is enough light for photosynthesis Found in shallow, clear, tropical seas

Coral Reefs Only outer layer of reef contains living coral Corals are predators that never chase their prey – Stinging polyps capture small animals –

Coral Reefs Threats: – Fragile ecosystems – Water temperature – Water pollution – Water quality- nutrients, sediments – Coral bleaching- when corals turn white and die – Main threats from human activities

Oceans Sunlight used for photosynthesis only penetrates about 100m into the ocean Most of ocean life concentrated in shallow, coastal waters

Oceans Plants and Animals: – Phytoplankton: in open ocean only grow in areas where there is enough light and nutrients – Open ocean one of least productive ecosystems A north Atlantic Ocean view of the spring phytoplankton bloom, as seen from a satellite image. Credit: Oregon State University

Oceans Plants and Animals: – Zooplankton: smallest herbivours, live near surface Jellyfish, shrimp, larvae of fish

Oceans Depths of oceans are dark Most food at the ocean floor consists of dead organisms Decomposers, filter feeders, and organisms that eat them live in the deep areas of ocean ac ac

Oceans Threats: – Pollution Comes from activities on land – Overfishing and fishing methods

Arctic and Antarctic Marine ecosystems because nearly all food comes from ocean and seas

Arctic and Antarctic Arctic ocean: rich in nutrients from surrounding land masses Supports large populations of plankton – Feed diversity of fish Fish feed diversity of birds, whales, seals

Arctic and Antarctic Antarctic: only continent never colonized by humans Only few plants grow at rocky edges on continent Plankton form bases of food web Nourish large numbers of fish, whales, birds