Aquatic Biodiversity

1. Aquatic Biodiversity Chapter 8

2. Why Should We Care about Coral Reefs • Biodiversity • 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. Gray reef shark Sea nettle Green sea turtle Parrot fish Fairy basslet Blue tang Sergeant major Algae Brittle star Hard corals Banded coral shrimp Coney Phytoplankton Symbiotic algae Coney Zooplankton Blackcap basslet Sponges Moray eel Bacteria Producer to primary consumer Secondary to higher-level consumer Primary to secondary consumer All consumers and producers to decomposers Fig. 8-11, p. 171

5. Nature of Aquatic Systems Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface with oceans dominating the planet. 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 • Aquatic life zones • Saltwater: marine • Oceans –Atlantic, Pacific, Arctic, Indian • estuaries • Coastlands and shorelines • Coral reefs • Mangrove forests • 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 – weakly swimming, free floating • Phytoplankton • Zooplankton • Ultraplankton – photosynthetic bacteria, 70% of the primary productivity near the ocean surface • Nekton – strongly swimming consumers • Benthos – bottom dwellers,(oysters,clams,worms) • Decomposers- bacteria

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

11. Marine Aquatic are important … Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services.

12. 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

13. 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

14. Estuaries and Coastal Wetlands • 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

15. 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

16. Herring gulls Peregrine falcon Snowy egret Cordgrass Short-billed dowitcher Marsh periwinkle Phytoplankton Smelt Zooplankton and small crustaceans Soft-shelled clam Bacteria Clamworm Producer to primary consumer Secondary to higher-level consumer Primary to secondary consumer All consumers and producers to decomposers Fig. 8-7a, p. 167

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

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

19. Rocky and Sandy Shores Host Different Types of Organisms • Intertidal zone – area of shoreline between low and high tides • Rocky shores- • Sandy shores: barrier beaches • Organism must be able to avoid be being swept away or crushed by waves. • Must survive changing levels of salinity • Importance of sand dunes – first line of defense against ravages of the sea

20. The Open Sea and Ocean Floor Host a Variety of Species • Vertical zones of the open sea • Euphotic zone-brightly lit upper zone, 40% of the world’s photosynthetic activity, nutrient levels low , DO high, predatory fish • Bathyal zone- dimly lit middle zone, smaller fishes • Abyssal zone: dark,cold,low DO • receives marine snow – dead and decaying organisms • Deposit feeders • Filter feeders • Upwellings • Primary productivity and NPP /unit area low, but the seas cover so much of the earth’s surface ,it is the largest contributor to earth’s overall NPP

21. 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

22. Case Study: The Chesapeake Bay—an Estuary in Trouble • Largest estuary –US • Increased population • Point/Nonpoint sources • High phosphate/nitrate • Overfishing • 1960 –polluted • 1983-Chesapeake Bay Program

23. Importance of freshwater systems Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.

24. Water Stands in Some Freshwater Systems and Flows in Others • Standing (lentic) bodies of freshwater • Lakes-vary in size , depth ,nutrient content • Ponds • Inland wetlands • Flowing (lotic) systems of freshwater • Streams • Rivers

25. Lakes…………… • Formation of lakes • Four zones based on depth and distance from shore • Littoral zone – near shore, shallow sunlit waters to the depth at which rooted plants stop growing , high biodiversity • Limnetic zone- open, sunlit surface away from shore, sunlight extends to the depth , main source of photosynthesis, microscopic plankton • Profundal zone-deep ocean water, very dark, low DO • Benthic zone – bottom of the lake, decomposers, detritus feeder nourished by dead matter that falls from littoral zone

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

27. 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

28. Some Lakes Have More Nutrients Than Others • Oligotrophic lakes • Low levels of nutrients and low NPP, • Eutrophic lakes • High levels of nutrients and high • Mesotrophic lakes – between the above 2 types • Cultural eutrophication ( human input of nutrients) leads to hypereutrophic lakes

29. Different types of Lakes • Oligotrophic lakes • Low levels of nutrients and low NPP, deep with steep banks. Water supplied by glaciers and mountain streams, crystal clear water • Crater Lake in Oregon

30. The Effect of Nutrient Enrichment on a Lake NPP- shallow, murky brown or green water with high turbidity. Lake in Western New York State Stepped Art Fig. 8-16a, p. 175

31. Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans • Surface water-precipitation that does not sink into the ground • Runoff – flows into stream • Watershed, drainage basin – land area that delivers runoff, sediment, dissolved substances • Three aquatic life zones • Source zone – head waters, clear cold, fast flowing • Transition zone wider, deeper, warmer streams • Floodplain zone – flow across flat valleys, higher temperatures, muddy, high concentrations of silt

32. 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 Stepped Art Fig. 8-17, p. 176

33. 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

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

35. Freshwater Inland Wetlands Are Vital Sponges • Marshes – dominated by grasses and weeds • Swamps - dominated by trees and shrubs • Prairie potholes- depressions carved ot by ancient glaciers • Floodplains- excess water during heavy rains and floods • Arctic tundra in summer -

36. 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

37. How Have Human Activities Affected Freshwater Ecosystems? • Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands.

38. 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

39. 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