Chapter 8 Aquatic Biodiversity
Core Case Study:Why Should We Care About Coral Reefs? Coral reefs form in clear, warm coastal waters of the tropics and subtropics. Formed by massive colonies of polyps. Figure 8-1
Core Case Study:Why Should We Care About Coral Reefs? Help moderate atmospheric temperature by removing CO2 from the atmosphere. Act as natural barriers that help protect 14% of the world’s coastlines from erosion by battering waves and storms. Provide habitats for a variety of marine organisms.
Estuaries and Coastal Wetlands: Centers of Productivity Estuaries provide ecological and economic services. Filter toxic pollutants, excess plant nutrients, sediments, and other pollutants. Reduce storm damage by absorbing waves and storing excess water produced by storms and tsunamis. Provide food, habitats and nursery sites for many aquatic species.
y Herring gulls Peregrine falcon Snowy Egret Cordgrass Short-billed Dowitcher Marsh Periwinkle Phytoplankton Smelt Zooplankton and small crustaceans Soft-shelled clam Clamworm Bacteria All consumers and producers to decomposers Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer Fig. 8-7
Case Study:Dams, Wetlands, Hurricanes, and New Orleans Dams and levees have been built to control water flows in New Orleans. Reduction in natural flow has destroyed natural wetlands. Causes city to lie below sea-level (up to 3 meters). Global sea levels have risen almost 0.3 meters since 1900.
Mangrove Forests Figure 6-8
What Kinds of Organisms Live in Aquatic Life Zones? Aquatic systems contain floating, drifting, swimming, bottom-dwelling, and decomposer organisms. Plankton: important group of weakly swimming, free-floating biota. Phytoplankton (plant), Zooplankton (animal), Ultraplankton (photosynthetic bacteria) Necton: fish, turtles, whales. Benthos: bottom dwellers (barnacles, oysters). Decomposers: breakdown organic compounds (mostly bacteria).
Rocky and Sandy Shores: Living with the Tides Organisms in intertidal zone develop specialized niches to deal with daily changes in: Wave action Figure 8-9
Human Activities Are Disrupting and Degrading Marine Systems Major threats to marine systems Coastal development Overfishing Runoff of nonpoint source pollution Point source pollution Habitat destruction Introduction of invasive species Climate change from human activities Pollution of coastal wetlands and estuaries
Freshwater Life Zones Sunlight Painted turtle Green frog Blue-winged teal Muskrat Pond snail Littoral zone Limnetic zone Diving beetle Plankton Profundal zone Benthic zone Northern pike Bloodworms Yellow perch Fig. 8-15
Effects of Plant Nutrients on Lakes:Too Much of a Good Thing Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support. Figure 8-16
River Systems Lake Glacier Rapids Waterfall Tributary Flood plain Oxbow lake Salt marsh Ocean Delta Deposited sediment Transition Zone Water Flood-Plain Zone Sediment • Runoff • Drainage basin • Watershed • Floodplain Rain and snow Source area Source Zone Fig. 8-17
Rachel Carson All at last returns to the sea-to Oceanus, the ocean river, like the ever-flowing stream of time, the beginning and the end. End chapter 8