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Aquatic Biodiversity

Aquatic Biodiversity. Chapters 8 and 11. WHY SHOULD WE CARE ABOUT CORAL REEFS?. Great biodiversity Formation- massive colonies of polyps that secrete limestone (CaCO3) around their soft bodies. Color from zooxanthellae algae that live in polyp tissue (mutualistic)

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Aquatic Biodiversity

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  1. Aquatic Biodiversity Chapters 8 and 11

  2. WHY SHOULD WE CARE ABOUT CORAL REEFS? • Great biodiversity • Formation- massive colonies of polyps that secrete limestone (CaCO3) around their soft bodies. Color from zooxanthellae algae that live in polyp tissue (mutualistic) • Important ecological and economic services • Moderate atmospheric temperatures by removing CO2 • Act as natural barriers protecting coasts from erosion • Provide habitats • Support fishing and tourism businesses • Provide jobs and building materials

  3. Degradation and decline of coral reefs • Coastal development • Pollution • Overfishing • Warmer ocean temperatures leading to coral bleaching • Increasing ocean acidity as CO2 is dissolved

  4. Clip on coral reef growing • Clip on fish blasting

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

  6. Aquatic life zones • Saltwater: marine • Oceans and estuaries • Coastlands and shorelines • Coral reefs • Mangrove forests • Freshwater • Rivers and streams • Inland wetlands • Lakes

  7. Where do Aquatic Species live?(life zones) • Plankton (free floating) • Phytoplankton (drifting plants like algae) • Zooplankton (drifting animals that are primary consumers like protozoa and jellyfish) • Ultraplankton(tiniest and most common- 70% of primary productivity near ocean surface) • Nekton-strong swimmers- turtles • Benthos- bottom dwellers, oysters • Decomposers- mostly bacteria

  8. 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

  9. PHOTOSYNTHESIS • Occurs only where light penetrates • Depth can be reduced by excess algal growth from nutrient overload which causes cloudiness (turbidity) which can happen naturally or be man made (coral reefs affected by silt runoff)

  10. Oceans Provide Important Ecological and Economic Resources • Reservoirs of diversity in three major life zones • Coastal zone • Usually high NPP • Open sea • Ocean bottom

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

  12. Continental shelf- 10% of ocean area, but 90% of all marine species. Sunlight and available nutrients give this ecosystem a high NPP • Euphotic zone- open ocean that receives sunlight

  13. Estuaries and Coastal Wetlands Are Highly Productive • Estuaries and coastal wetlands (coastal land areas covered with water all or part of the year) • River mouths • Inlets • Bays • Sounds • Salt marshes - temperate zones • Mangrove forests- tropical zones

  14. Another component of coastal marine biodiversity • Seagrass Beds • Support a variety of marine species • Stabilize shorelines • Reduce wave impact

  15. MANGROVES These areas are tough places for plants to grow. During low tides intertidal zones are exposed to air and during high tides they’re covered by salt water. They flood frequently and have poor soil. But mangrove trees survive and even thrive in these harsh conditions The roots “breathe” through knobby holes called lenticels. They take in CO2 directly from the air, instead of from the soil like other plants.

  16. Rocky and Sandy Shores Host Different Types of Organisms • Intertidal zone- area between low and high tide • Rocky shores • Sandy shores: barrier beaches • Organism adaptations necessary to deal with daily salinity and moisture changes • Importance of sand dunes first line of defense against storms

  17. Primary and Secondary Dunes

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

  19. The Open Sea and Ocean Floor Host a Variety of Species • Vertical zones of the open sea • Euphotic zone- nutrient levels low, dissolved oxygen high. Lots of drifting phytoplankton that carry out 40% of world’s photosynthetic activity • Bathyal zone- middle zone, little sunlight, no photosynthesizers. Contains zooplankton and small fish

  20. Abyssal zone- dark, cold, little dissolved oxygen Contains lots of nutrients to support a large number of species • marine snow – organisms get food from dead and decaying organisms floating down from above • Deposit feeders – worms, take in mud to extract nutrients • Filter feeders - pass water over or thru their bodies to get nutrients

  21. Upwellings – areas where nutrients from the bottom move to the surface • Primary productivity and NPP – very little NPP in the open sea, but because the ocean is so big, the NPP is the largest of the earth’s.

  22. Phytoplankton This large grouping is composed mostly of single-celled algae and bacteria. (Diatoms) Zooplankton protozoa, small crustaceans, jellyfish and worms

  23. Human Activities Are Disrupting and Degrading Marine Systems • Major threats to marine systems • Coastal development • Overfishing • Runoff of nonpoint source pollution • Point source pollution- sewage from passenger ships and oil spills • Habitat destruction • Introduction of invasive species • Climate change from human activities • Pollution of coastal wetlands and estuaries

  24. Coastal Development • 45% of the world’s population lives along or near coasts and • Over 50% of the US population lives along or near coasts

  25. Over ½ the US population and 45% of the world’s population lives near the coast By 2040, it is projected that up to 80% will live near coasts!

  26. Overfishing and fishing methods- bottom trawling, longlining and drift nets- dynamite and cyanide fishing

  27. Humphead wrasse

  28. The largest estuary in the US is the Chesapeake Bay The Chesapeake Bay was formed at the end of the last ice age as melting glaciers filled the Susquehanna River Valley. It is the largest estuary in the United States and the third largest in the world. It is home to 3,600 different species of plants and animals, and nearly 17 million people. But the bay is suffering; and this has resulted in a number of endangered species both in its waters and along the shores.

  29. The population of the bay oysters and the blue crab are now threatened due to overharvesting and pollution. • The main pollutants are nitrates and phosphates released from agriculture.

  30. CHESAPEAKE BAY PROGRAM • 1983 • Integrated coastal management which included citizen groups, communities and state and federal governments Strategies included land-use regulations, banning phosphate detergents, upgrading sewage treatment plants and monitoring industrial discharges Wetlands were restored and sea grasses planted

  31. Oysters used to filter and clean the bay every 3 days- this removed excess nutrients and reduced algal blooms • Now the filtration process takes a year! • Should the non-native Asian oyster be introduced? (denied) • Improvements have been made and there is some significant improvement, but still a long way to go

  32. WHY ARE FRESHWATER ECOSYSTEMS IMPORTANT? • Standing (lentic) bodies of freshwater • Lakes • Ponds • Inland wetlands • Flowing (lotic) systems of freshwater • Streams • Rivers

  33. Formation of lakes • Formed when precipitation, runoff or groundwater seepage fills depressions in the earth’s surface. • Cause of depressions= glaciation (Lake Louise, crustal displacement and volcanic lake (Crater Lake in Oregon)

  34. Crater Lake • Crater Lake was formed when a massive eruption of Mount Mazama 7700 years ago caused the mountain to collapse, leaving a steaming caldera. • Centuries of rain and snow filled the caldera creating Crater Lake. • There are 2 islands in the crater.

  35. Four zones based on depth and distance from shore • Littoral zone • near shore, shallow sunlit water with high biological diversity • Limnetic zone • open, sunlit surface away from shore which produces food and oxygen that supports most of the consumers • Profundal zone • deep, dark, open water with low oxygen levels • Benthic zone • bottom layer inhabited by decomposers, detritus feeders and some fish that are nourished by dead matter that falls down

  36. Some Lakes Have More Nutrients Than Others • Oligotrophic lakes • Low levels of nutrients and low NPP • Deep with steep banks • Crystal clear water with small populations • Eutrophic lakes • High levels of nutrients and high NPP • Shallow, murky, high turbidity • Mesotrophic lakes • Lake with conditions between the two • Cultural eutrophication leads to hypereutrophic lakes which occurs due to human imputs

  37. Adapted from Ms. J. Root’s power point

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