Aquatic Biodiversity

1. Aquatic Biodiversity Chapter 8

2. Core Case Study: Why Should We Care about Coral Reefs? • Biodiversity • Formation – coral polyps + algae • 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? • Degradation and decline • Coastal development • Pollution • Overfishing • Warmer ocean temperatures leading to coral bleaching • Increasing ocean acidity

4. 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.

5. Most of the Earth Is Covered with Water (~70%) • Saltwater: global ocean divided into 4 areas • Atlantic • Pacific • Arctic • Indian • Freshwater

6. Most of the Earth Is Covered with Water • Aquatic life zones • Saltwater: marine • Oceans and estuaries • Coastlands and shorelines • Coral reefs • Mangrove forests (see Mangrove Adventure video in Ch. 9-11 folder) • Freshwater • Lakes • Rivers and streams • Inland wetlands

7. The Ocean Planet

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

9. Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water • Plankton • Phytoplankton • Phyto: plant, plankton: difting • Primary producers • Zooplankton – zoo: animal • Ultraplankton • photosynthetic bacteria • 70% of primary productivity near ocean surface • Nekton – strong swimmers • Benthos – bottom dwellers • Decomposers

10. Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water • 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 • Light can be reduced by turbidity – cloudiness caused by algal blooms or sediment

11. Testing turbidity

12. 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.

13. Oceans Provide Important Ecological and Economic Resources • Reservoirs of diversity in three major life zones • Coastal zone – 10% of ocean, 90% of marine species! • Usually high NPP – due to ample sunlight and nutrients • Open sea – nutrients in short supply • Euphotic zone: 40% of the world’s photosynthesis! • Ocean bottom

14. NATURAL CAPITAL Marine Ecosystems Ecological Services Economic Services Climate moderation Food CO2 absorption Animal and pet feed Nutrient cycling Pharmaceuticals Waste treatment Harbors and transportation routes 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 Scientific information Building materials Fig. 8-4, p. 165

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

16. Estuaries and Coastal Wetlands Are Highly Productive • Estuaries and coastal wetlands - high nutrient input from rivers • River mouths • Inlets • Bays • Sounds • Salt marshes • Mangrove forests • Seagrass Beds • Support a variety of marine species • Stabilize shorelines • Reduce wave impact

17. Estuaries and Coastal Wetlands Are Highly Productive • 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

18. View of an Estuary from Space

19. Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area

20. Rocky and Sandy Shores Host Different Types of Organisms • Intertidal zone – tides rise and fall every 6 hours • Rocky shores • Sandy shores: barrier beaches • Organism adaptations necessary to deal with daily salinity and moisture changes – hold onto something, protective shell, dig into mud • Importance of sand dunes – plant roots hold sand in place. They protect inland areas from the sea.

21. Hermit crab Sea star Shore crab Rocky Shore Beach High tide Periwinkle Sea urchin Anemone Mussel Low tide Sculpin Barnacles Sea lettuce Kelp Beach flea Monterey flatworm Tiger beetle Peanut worm Nudibranch Barrier Beach Clam Blue crab Dwarf olive High tide Sandpiper Ghost shrimp Silversides Low tide Mole shrimp White sand macoma Sand dollar Moon snail Living between the Tides Stepped Art Fig. 8-9, p. 169

22. Primary and Secondary Dunes

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

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

25. The Open Sea and Ocean Floor Host a Variety of Species • Vertical zones of the open sea • Euphotic zone – Eu:good, phot: light • Bathyal zone - dim light • Abyssal zone: receives marine snow • Deposit feeders – eat mud (worms) • Filter feeders - filter water (shellfish, sponges) • Upwellings – bring nutrients up from bottom, caused by winds and ocean currents • Primary productivity and NPP – low per unit area, but since area is so large, large overall

26. Littoral – between high and low water mark in rivers, lakes, seas And areas near shorelines Abyssal– sea floor Hadal – (like Hades) – deep sea trenches

27. http://www.youtube.com/watch?v=8101vCjM7nY http://www.youtube.com/watch?v=c-cYksk1Z70

28. 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.

29. 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

30. Case Study: The Chesapeake Bay—an Estuary in Trouble • Largest estuary in the US; polluted since 1960 • Population increased • Point and nonpoint sources raised pollution • Phosphate and nitrate levels too high • Overfishing • 1983: Chesapeake Bay Program • Update on recovery of the Bay • Should we introduce an Asian oyster? • Pros: • Cons:

31. Chesapeake Bay

32. 8-4 Why Are Freshwater Ecosystems Important? • Concept 8-4 Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.

33. Water Stands in Some Freshwater Systems and Flows in Others • Standing (lentic) bodies of freshwater • Lakes • Ponds • Inland wetlands • Flowing (lotic) systems of freshwater • Streams • Rivers

34. Water Stands in Some Freshwater Systems and Flows in Others • Formation of lakes • Glaciation • Crustal displacement • Volcanic activity • Four zones based on depth and distance from shore • Littoral zone – near shore • Limnetic zone – open water, top layer • Profundal zone – too dark for photosynthesis • Benthic zone – bottom, decomposers and detritivores live here

35. 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

36. Distinct Zones of Life in a Fairly Deep Temperate Zone Lake

37. Some Lakes Have More Nutrients Than Others • Oligotrophic lakes • Low levels of nutrients and low NPP • Steep banks, deep water • Eutrophic lakes • High levels of nutrients and high NPP • Mesotrophic lakes – (meso = middle) • Cultural eutrophication leads to hypereutrophiclakes

38. The Effect of Nutrient Enrichment on a Lake

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

40. Lake Rain and snow Glacier Rapids Waterfall Tributary Flood plain Oxbow lake Salt marsh Deposited sediment Delta Ocean Source Zone Transition Zone Water Sediment Floodplain Zone Three Zones in the Downhill Flow of Water Stepped Art Fig. 8-17, p. 176

41. 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

42. New Orleans, Louisiana, (U.S.) and Hurricane Katrina

43. Projection of New Orleans if the Sea Level Rises 0.9 Meter

44. Freshwater Inland Wetlands Are Vital Sponges • Marshes • Swamps • Prairie potholes • Floodplains • Arctic tundra in summer

45. Freshwater Inland Wetlands Are Vital Sponges • 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

46. 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.

47. 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

48. 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