11/3/13. Aquatic Biodiversity. Chapter What Is the General Nature of Aquatic Systems? Most of the Earth Is Covered with Water

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1 Aquatic Biodiversity Chapter What Is the General Nature of Aquatic Systems? Concept 8-1A Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth s surface with oceans dominating the planet. Concept 8-1B The key factors determining biodiversity in aquatic systems are temperature, dissolved oxygen content, availability of food and availability of light and nutrients necessary for photosynthesis. Most of the Earth Is Covered with Water Aquatic life zones Saltwater: marine Oceans and estuaries Coastlands and shorelines Coral reefs Mangrove forests Freshwater Lakes Rivers and streams Inland wetlands 1

2 Distribution of the World s Major Saltwater and Freshwater Sources Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (1) Plankton (drifters) Phytoplankton Zooplankton Ultraplankton Nekton (swimmers) Benthos (bottom dwellers) Decomposers (fungi & bacteria) Video: Schooling fish 2

3 Video: Giant clam Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (2) Key factors in the distribution of organisms Temperature Dissolved oxygen content Availability of food Availability of light and nutrients needed for photosynthesis in the euphotic, or photic, zone 8-2 Why Are Marine Aquatic Systems Important? Concept 8-2 Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services. 3

4 Oceans Provide Important Ecological and Economic Resources Reservoirs of diversity in three major life zones Coastal zone Usually high NPP Open sea Ocean bottom NATURAL CAPITAL Marine Ecosystems Ecological Services Climate moderation CO 2 absorption Nutrient cycling Waste treatment Reduced storm impact (mangroves, barrier islands, coastal wetlands) Habitats and nursery areas Genetic resources and biodiversity Scientific information Economic Services Food Animal and pet feed Pharmaceuticals Harbors and transportation routes Coastal habitats for humans Recreation Employment Oil and natural gas Minerals Building materials Fig. 8-4, p. 165 High tide Estuarine Zone Low tide Coastal Zone Continental shelf Open Sea Sea level Euphotic Zone Sun Depth in meters Bathyal Zone 500 1,000 1,500 Photosynthesis Twilight Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline. Abyssal Zone 2,000 3,000 4,000 5,000 10,000 Darkness Water temperature ( C) Fig. 8-5, p

5 Estuaries and Coastal Wetlands Are Highly Productive (1) Estuaries and coastal wetlands River mouths Inlets Bays Sounds Salt marshes Mangrove forests Seagrass Beds Support a variety of marine species Stabilize shorelines Reduce wave impact Estuaries and Coastal Wetlands Are Highly Productive (2) Important ecological and economic services Coastal aquatic systems maintain water quality by filtering Toxic pollutants Excess plant nutrients Sediments Absorb other pollutants Provide food, timber, fuelwood, and habitats Reduce storm damage and coast erosion View of an Estuary from Space 5

6 Some Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area Herring gulls Peregrine falcon Snowy egret Cordgrass Short-billed dowitcher Phytoplankton Smelt Marsh periwinkle Zooplankton and small crustaceans Soft-shelled clam Bacteria Clamworm Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All consumers and producers to decomposers Fig. 8-7a, p. 167 Mangrove Forest in Daintree National Park in Queensland, Australia 6

7 Rocky and Sandy Shores Host Different Types of Organisms Intertidal zone (Fig. 8-9) Rocky shores Sandy shores: barrier beaches Organism adaptations necessary to deal with daily salinity and moisture changes Importance of sand dunes (Fig. 8-10) Sea star Hermit crab Shore crab High tide Periwinkle Sea urchin Anemone Sculpin Low tide Mussel Rocky Shore Beach Nudibranch Peanut worm Blue crab Monterey flatworm Dwarf olive Kelp Clam High tide Barnacles Sea lettuce Beach flea Tiger beetle Sandpiper Silversides Low tide Mole shrimp Ghost shrimp Barrier Beach White sand macoma Sand dollar Moon snail Fig. 8-9, p. 169 Primary and Secondary Dunes Ocean Beach Primary Dune Recreation, no building Walkways, no building Trough Secondary Dune Back Dune Limited Walkways, recreation and no building walkways Bay or Lagoon Most suitable for Recreation development Grasses or shrubs Taller shrubs Taller shrubs and trees Bay shore Fig. 8-10, p

8 Coral Reefs Are Amazing Centers of Biodiversity Marine equivalent of tropical rain forests Habitats for one-fourth of all marine species Coral Reef Trophic Interactions Gray reef shark Parrot fish Sea nettle Green sea turtle Blue Fairy basslet tang Hard corals Algae Symbiotic algae Phytoplankton Brittle star Sergeant major Banded coral Coney shrimp Coney Zooplankton Blackcap basslet Sponges Bacteria Moray eel Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All consumers and producers to decomposers Fig. 8-11, p. 171 Video: Florida reefs 8

9 Video: Reef fish (Bahamas) The Open Sea and Ocean Floor Host a Variety of Species Vertical zones of the open sea (Fig. 8-5) Euphotic zone Bathyal zone Abyssal zone: receives marine snow Deposit feeders Filter feeders Upwelling zones Primary productivity and NPP Animation: Ocean provinces 9

10 8-3 How Have Human Activities Affected Marine Ecosystems? Concept 8-3 Human activities threaten aquatic biodiversity and disrupt ecological and economic services provided by saltwater systems. 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 Video: ABC News: Beach pollution 10

11 8-4 Why Are Freshwater Ecosystems Important? Concept 8-4 Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity. Water Stands in Some Freshwater Systems and Flows in Others (1) Standing (lentic) bodies of freshwater Lakes Ponds Inland wetlands Flowing (lotic) systems of freshwater Streams Rivers Water Stands in Some Freshwater Systems and Flows in Others (2) Formation of lakes Four zones based on depth and distance from shore (Fig. 8-15) Littoral zone Limnetic zone Profundal zone Benthic zone 11

12 NATURAL CAPITAL Freshwater Systems Ecological Services Climate moderation Nutrient cycling Waste treatment Flood control Groundwater recharge Habitats for many species Genetic resources and biodiversity Scientific information Economic Services Food Drinking water Irrigation water Hydroelectricity Transportation corridors Recreation Employment Fig. 8-14, p. 174 Distinct Zones of Life in a Temperate Zone Lake Green frog Painted turtle Sunlight Blue-winged teal Muskrat Pond snail Littoral zone Plankton Limnetic zone Diving beetle Yellow perch Profundal zone Benthic zone Bloodworms Northern pike Fig. 8-15, p. 175 Some Lakes Have More Nutrients Than Others Oligotrophic lakes Low levels of nutrients and low NPP Eutrophic lakes High levels of nutrients and high NPP Mesotrophic lakes Cultural eutrophication leads to hypereutrophic lakes 12

13 Animation: Trophic natures of lakes The Effect of Nutrient Enrichment on a Lake Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans Surface water Runoff Watershed, drainage basin Three aquatic life zones in downhill flow (Fig. 18.7) Source zone Transition zone Floodplain zone 13

14 Rain and snow Source Zone Lake Three Zones in the Downhill Flow of Water Glacier Rapids Waterfall Tributary Flood plain Oxbow lake Salt marsh Delta Deposited sediment Ocean Transition Zone Floodplain Zone Water Sediment Fig. 8-17, p. 176 Case Study: Dams, Deltas, Wetlands, Hurricanes, and New Orleans Coastal deltas, mangrove forests, and coastal wetlands: natural protection against storms Dams and levees reduce sediments in deltas: significance? New Orleans, Louisiana, and Hurricane Katrina: August 29, 2005 Global warming, sea rise, and New Orleans New Orleans, Louisiana, (U.S.) and Hurricane Katrina 14

15 Projection of New Orleans if the Sea Level Rises 0.9 Meter Freshwater Inland Wetlands Are Vital Sponges (1) Marshes Swamps Prairie potholes Floodplains Arctic tundra in summer Freshwater Inland Wetlands Are Vital Sponges (2) Provide free ecological and economic services Filter and degrade toxic wastes Reduce flooding and erosion Help to replenish streams and recharge groundwater aquifers Biodiversity Food and timber Recreation areas 15

16 8-5 How Have Human Activities Affected Freshwater Ecosystems? Concept 8-5 Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands. Human Activities Are Disrupting and Degrading Freshwater Systems Impact of dams and canals on rivers Impact of flood control levees and dikes along rivers Impact of pollutants from cities and farms on rivers Impact of drained wetlands Case Study: Inland Wetland Losses in the United States Loss of wetlands has led to Increased flood and drought damage Lost due to Growing crops Mining Forestry Oil and gas extraction Building highways Urban development 16