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Aquatic Biodiversity

Aquatic Biodiversity. Chapter 8. Core Case Study: Why Should We Care about Coral Reefs? (1). Biodiversity Formation Important ecological and economic services Moderate atmospheric temperatures Act as natural barriers protecting coasts from erosion Provide habitats

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Aquatic Biodiversity

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  1. Aquatic Biodiversity Chapter 8

  2. Core Case Study: Why Should We Care about Coral Reefs? (1) • Biodiversity • Formation • Important ecological and economic services • Moderate atmospheric temperatures • Act as natural barriers protecting coasts from erosion • Provide habitats • Support fishing and tourism businesses • Provide jobs and building materials • Studied and enjoyed

  3. Core Case Study: Why Should We Care about Coral Reefs? (2) • Degradation and decline • Coastal development • Pollution • Overfishing • Warmer ocean temperatures leading to coral bleaching • Increasing ocean acidity

  4. A Healthy Coral Reef in the Red Sea

  5. 8-1 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.

  6. Most of the Earth Is Covered with Water (1) • Saltwater: global ocean divided into 4 areas • Atlantic • Pacific • Arctic • Indian • Covers 71% of the Earth’s surface • Freshwater- covers 2.2% of the Earth’s surface

  7. Most of the Earth Is Covered with Water (2) • Aquatic life zones- equivalent to biomes • Saltwater: marine • Oceans and estuaries • Coastlands and shorelines • Coral reefs • Mangrove forests • Freshwater • Lakes • Rivers and streams • Inland wetlands

  8. The Ocean Planet

  9. Distribution of the World’s Major Saltwater and Freshwater Sources

  10. Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (1) • Plankton- free floating • Phytoplankton- producers • Zooplankton- consumers • Ultraplankton- photosynthetic bacteria • Nekton- free swimming- fish, turtles, whales • Benthos- bottom dwellers • Decomposers- mostly bacteria

  11. dinoflagellate radiolarian

  12. Shrimp larva Anemone larva Worm larva Worm larva copepod

  13. 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 • Depth of the euphotic zone can be decreased by turbidity- (cloudiness)

  14. Ted video

  15. 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.

  16. Major Ecological and Economic Services Provided by Marine Systems

  17. Oceans Provide Important Ecological and Economic Resources • Reservoirs of diversity in three major life zones • Coastal zone- warm, nutrient rich, shallow water from high tide mark to the edge of the continental shelf • Makes up less than 10% of ocean area, but holds 90% of species • Usually high NPP- due to high nutrients and sunlight • Open sea- • Ocean bottom

  18. Natural Capital: Major Life Zones and Vertical Zones in an Ocean

  19. High tide Sun Low tide Depth in meters Open Sea Coastal Zone Sea level 0 50 Photosynthesis Euphotic Zone Estuarine Zone 100 Continental shelf 200 500 Bathyal Zone Twilight 1,000 1,500 2,000 Abyssal Zone Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline . 3,000 Darkness 4,000 5,000 10,000 0 5 10 15 20 25 30 Water temperature (°C) Fig. 8-5, p. 166

  20. Estuaries and Coastal Wetlands Are Highly Productive (1) • Estuaries and coastal wetlands(where fresh and salt water combine) • River mouths • Inlets • Bays • Sounds • Salt marshes • Mangrove forests • Seagrass Beds • Support a variety of marine species • Stabilize shorelines • Reduce wave impact

  21. 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

  22. View of an Estuary from Space

  23. Some Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area

  24. Fig. 8-7b, p. 167

  25. Mangrove Forest in Daintree National Park in Queensland, Australia

  26. Rocky and Sandy Shores Host Different Types of Organisms • Intertidal zone- area of shoreline between high and low tide • Rocky shores- lots of species, seasonal changes in salinity, temperature and water flow • Sandy shores: barrier beaches • Organism adaptations necessary to deal with daily salinity and moisture changes- digging, burrowing, tunneling • Importance of sand dunes- protect from erosion

  27. Living between the Tides

  28. Primary and Secondary Dunes

  29. Coral Reefs Are Amazing Centers of Biodiversity • Marine equivalent of tropical rain forests • Habitats for one-fourth of all marine species

  30. Natural Capital: Some Components and Interactions in a Coral Reef Ecosystem

  31. The Open Sea and Ocean Floor Host a Variety of Species • Vertical zones of the open sea • Euphotic zone- brightlylit- phytoplankton carry out 40% of the worlds photosynthesis • Bathyal zone- dimly lit middle zone • Abyssal zone: receives marine snow • Deposit feeders • Filter feeders • Upwellings- bring nutrients from the bottom to the surface • Primary productivity and NPP- low per unit area- high NPP contribution for the earth

  32. Animation: Ocean provinces

  33. 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.

  34. 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

  35. Case Study: The Chesapeake Bay—an Estuary in Trouble (1) • Largest estuary in the US; polluted since 1960 • Population increased • Point and nonpoint sources raised pollution • Phosphate and nitrate levels too high

  36. Case Study: The Chesapeake Bay—an Estuary in Trouble (2) Overfishing 1983: Chesapeake Bay Program Update on recovery of the Bay Should we introduce an Asian oyster?

  37. Chesapeake Bay

  38. 8-4 Why Are Freshwater Ecosystems Important? • Concept 8-4 Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.

  39. 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

  40. Water Stands in Some Freshwater Systems and Flows in Others (2) • Formation of lakes • Four zones based on depth and distance from shore • Littoral zone- top, near the shore, full light, • Limnetic zone- open, sunlit, away from shore • Profundal zone-deep open water, too dark for photosynthesis • Benthic zone-bottom- decomposers, detritus feeders, some fish

  41. NATURAL CAPITAL Freshwater Systems Ecological Services Economic Services Climate moderation Food Nutrient cycling Drinking water Waste treatment Irrigation water Flood control Hydroelectricity Groundwater recharge Transportation corridors Habitats for many species Genetic resources and biodiversity Recreation Employment Scientific information Fig. 8-14, p. 174

  42. Sunlight Blue-winged teal Painted turtle Green frog Muskrat Pond snail Littoral zone Plankton Limnetic zone Diving beetle Profundal zone Northern pike Benthic zone Yellow perch Bloodworms Fig. 8-15, p. 175

  43. Some Lakes Have More Nutrients Than Others • Oligotrophic lakes • Deep lakes, steep sides, low levels of nutrients and low NPP • Eutrophic lakes • High levels of nutrients and high NPP • Mesotrophic lakes • Cultural eutrophication leads to hypereutrophic lakes

  44. The Effect of Nutrient Enrichment on a Lake

  45. Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans • Surface water- precip that does not sink or evaporate • Runoff- surface water that flows into streams • Watershed, drainage basin- land area that delivers run-off, sediment and dissolved substances to a stream

  46. Three aquatic life zones • Source zone-mountain head waters, shallow, swiftly moving streams- cold, clear- lots of dissolved oxygen- not very productive due to low nutrients • Transition zone- wider, deeper, warmer streams that flow down gentler slopes, more turbid- less DO- more productivity

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