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Chapter 8 Aquatic Biodiversity

Chapter 8 Aquatic Biodiversity. A Healthy Coral Reef in the Red Sea. Fig. 8-1, p. 168. 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.

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Chapter 8 Aquatic Biodiversity

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  1. Chapter 8 Aquatic Biodiversity

  2. A Healthy Coral Reef in the Red Sea Fig. 8-1, p. 168

  3. 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.

  4. Most of the Earth Is Covered with Water (1) • Saltwater: global ocean divided into 4 areas • Atlantic • Pacific: • Arctic • Indian • Freshwater

  5. Sect Earth’s Oceans • All of the oceans are joined in a single large interconnected body of water called the world ocean. The world ocean play important roles in the regulation of the planet’s environment.

  6. Earth’s Ocean • The largest ocean on Earth is the Pacific Ocean with a surface area of about 165,640,000 km2. • The deepest point on the ocean floor, the Challenger Deep, is found in the Pacific Ocean. • The Challenger Deep is located east of the Philippine islands and the bottom of the Mariana Trench and is 11,033m below sea level which is deeper than Mount Everest is tall.

  7. Earth’s Ocean • The second largest ocean on Earth is the Atlantic Ocean, and covers about half the area of the Pacific Ocean which is a surface area of about 81,630,000 km2. • The Indian Ocean is the third largest ocean on Earth with a surface area of 73,420,000 km2. • The smallest ocean is the Artic ocean which covers 14,350,000 km2

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

  9. Aquatic Systems Fig. 8-3, p. 170

  10. Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (1) • Plankton: free floating • Phytoplankton • Primary producers for most aquatic food webs • Zooplankton • Primary and secondary consumers • Single-celled to large invertebrates like jellyfish • Ultraplankton • Tiny photosynthetic bacteria

  11. Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (2) • Nekton • Strong swimmers: fish, turtles, whales • Benthos • Bottom dwellers: oysters, sea stars, clams, lobsters, crabs • Decomposers • Mostly bacteria PLANKTON. BENTHOS. NEKTON • https://www.youtube.com/watch?v=sIaxSxEqKtA

  12. Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (3) • 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 (photic) zone • Turbidity: degree of cloudiness in water • Inhibits photosynthesis, often due to Algal blooms.

  13. Four Types of Aquatic Life Forms Fig. 8-4, p. 171

  14. 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.

  15. Oceans Provide Vital Ecological and Economic Resources • Estimated $12 trillion per year in goods and services • Reservoirs of diversity in three major life zones • Coastal zone • Warm, nutrient rich, shallow • Shore to edge of continental shelf • Usually high NPP from ample sunlight and nutrients • Open sea • Ocean bottom

  16. Natural Capital Marine Ecosystems Ecological Services Economic Services Climate moderation Food CO 2 absorption Animal and pet feed Pharmaceuticals Nutrient cycling Harbors and transportation routes Waste treatment Reduced storm impact (mangroves, barrier islands, coastal wetlands) Coastal habitats for humans Recreation Habitats and nursery areas Employment Oil and natural gas Genetic resources and biodiversity Minerals Building materials Scientific information Fig. 8-5, p. 172

  17. Estuaries and Coastal Wetlands Are Highly Productive (1) • Estuaries and coastal wetlands • Where rivers meet the sea • Seawater mixes with freshwater • Very productive ecosystems: high nutrient levels • River mouths • Inlets • Bays • Sounds • Salt marshes • Mangrove forests

  18. View of an Estuary from Space Fig. 8-7, p. 173

  19. Estuaries and Coastal Wetlands Are Highly Productive (2) • Seagrass Beds • Grow underwater in shallow areas • Support a variety of marine species • Stabilize shorelines • Reduce wave impact • Mangrove forests • Along tropical and subtropical coastlines • 69 different tree species that grow in saltwater

  20. See Grass Bed Organisms Fig. 8-9, p. 174

  21. Mangrove Forest in Australia Fig. 8-10, p. 175

  22. Estuaries and Coastal Wetlands Are Highly Productive (3) • 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

  23. Rocky and Sandy Shores Host Different Types of Organisms • Intertidal zone • Rocky shores • Sandy shores: barrier beaches • Organism adaptations necessary to deal with daily salinity and moisture changes • Importance of sand dunes

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

  25. Life Zones in the Ocean • The oceans are vastly deep, and the depth of the ocean has an effect on the marine life that lives there. 1) Epipelagic Zone: Top zone of the ocean. This area is full of life because there is enough sunlight to sustain photosynthesis. This zone is also called the Euphotic Zone. 2) Mesopelagic Zone: This zone gets sunlight but not enough to sustain photosynthesis. This zone is also called the Disphotic Zone.

  26. Life Zones in the Ocean 3) Bathypelagic Zone: This is the lowest level on the continental shelf. This layer is the first of the Aphotic Zonebecause it receives no light at all. This means there is no creature like plants to create food. All the food in this zone comes from dead material floating from the higher layers.

  27. Life Zones in the Ocean 4) Abyssopelagic Zone (ABANDON ALL HOPE YE WHO ENTER HERE…): This is the largest layer of the ocean. It is completely dark, and the oxygen concentration is very low. Pressure in this zone is extreme. No light penetrates its depth, yet it supports some of the strangest creatures on earth. This is the deepest layer of the ocean, called the Aphotic Zonebecause it receives no light at all. Creatures that live in this environment cannot be brought to higher layers because they will die in the low pressure.

  28. Life Zones in the Ocean 5) Hadalpelagic Zone: This is the zone in the Mariana Trench and other trenches. It shares the same characteristics as the Abyssal Zone except it is even deeper.

  29. Ocean Zones Depths of Ocean Zones Epipelagic zone: Surface – 650 ft Mesepelagic: 650 ft – 3300ft Bathypelagic Zone: 3300 ft- 13000ft Abyssal Zone: 13000ft- ~20000ft Hadopelagic: 20000ft and below

  30. Light and Life Zones

  31. Temperature Zones • The surface of the ocean is warmed by the sun, while the depths of the ocean, where sunlight never reaches, are very cold, just above freezing. • Surface waters are stirred up by waves and currents so the warm surface zone may be as much as 350 m deep. • Below the surface zone is the thermocline, which is layer about 300 to 700 m deep where the temperature falls rapidly.

  32. Section 3 Temperature Zones

  33. The Open Sea and Ocean Floor Host a Variety of Species (1) • Three vertical zones of the open sea • Euphotic zone • Phytoplankton • Nutrient levels low • Dissolved oxygen levels high • Bathyal zone • Dimly lit • Zooplankton and smaller fishes

  34. The Open Sea and Ocean Floor Host a Variety of Species (2) • Abyssal zone • Dark and cold • High levels of nutrients • Little dissolved oxygen • Deposit feeders • Filter feeders • Upwelling brings nutrients to euphotic zone • Primary productivity and NPP

  35. 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.

  36. Human Activities Are Disrupting and Degrading Marine Systems • Major threats to marine systems • Coastal development • Overfishing • Use of fishing trawlers • 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

  37. Drainage basin No oxygen Low concentrations of oxygen Fig. 8-14, p. 180

  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) • Four zones based on depth and distance from shore • Littoral zone • Near shore where rooted plants grow • High biodiversity • Turtles, frogs, crayfish, some fish • Limnetic zone • Open, sunlight area away from shore • Main photosynthetic zone • Some larger fish

  41. Water Stands in Some Freshwater Systems and Flows in Others (3) • Profundal zone • Deep water too dark for photosynthesis • Low oxygen levels • Some fish • Benthic zone • Decomposers • Detritus feeders • Some fish • Nourished primarily by dead matter

  42. Some Lakes Have More Nutrients Than Others • Oligotrophic lakes • Low levels of nutrients and low NPP • Very clear water • Eutrophic lakes • High levels of nutrients and high NPP • Murky water with high turbidity • Mesotrophic lakes • Cultural eutrophication of lakes from human input of nutrients

  43. The Effect of Nutrient Enrichment on a Lake Fig. 8-17, p. 182

  44. Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans • Surface water • Runoff • Watershed, drainage basin • Three aquatic life zones • Source zone • Transition zone • Floodplain zone

  45. Freshwater Inland Wetlands Are Vital Sponges (1) • Marshes • Swamps • Prairie potholes • Floodplains • Arctic tundra in summer

  46. 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

  47. 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.

  48. 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 streams, rivers, and lakes • Impact of drained wetlands

  49. Three Big Ideas • Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface, and oceans dominate the planet. • The earth’s aquatic systems provide important ecological and economic services. • Human activities threaten biodiversity and disrupt ecological and economic services provided by aquatic systems.

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