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Aquatic Ecosystems & Biodiversity

Aquatic Ecosystems & Biodiversity. AP Environmental Science. Aquatic Systems. Earths Surface: 71% Ocean (Marine) 2.2% Fresh Water Total Water 97% Ocean (Marine) 3% Fresh Water. Aquatic Ecosystems & Biodiversity. Niches & organisms. Four Major Types of Organisms in Aquatic Ecosystems.

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Aquatic Ecosystems & Biodiversity

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  1. Aquatic Ecosystems & Biodiversity AP Environmental Science

  2. Aquatic Systems • Earths Surface: • 71% Ocean (Marine) • 2.2% Fresh Water • Total Water • 97% Ocean (Marine) • 3% Fresh Water

  3. Aquatic Ecosystems & Biodiversity Niches & organisms

  4. Four Major Types of Organisms in Aquatic Ecosystems • Plankton- • Free-floating, weakly swimming, one-celled organisms. • Phytoplankton, Zooplankton, Ultraplankton • Benthos: bottom feeders • Craps, filter-feeders, etc • Upwelling brings this “marine snow” back up to the surface for other fish as well • Necton: fish, turtles, whales • Decomposers: mostly bacteria

  5. Niches

  6. Phytoplankton • Phytoplankton (plant plankton) • Aquatic Ecosystems are mostly dependent on these photosynthetic organisms to support the food web • In oceans, most photosynthetic activity is near coastlines • Nitrogen, phosphorous, other nutrients runoff into the ocean • Ocean currents distribute nutrients and phytoplankton by carrying them away from shore • Description – small drifting plants • Niche – they are producers that support most aquatic food chains • Example – cyanobacteria & many types of algae

  7. Zooplankton • Zooplankton (animal plankton) • Description – herbivores that feed on phytoplankton or other zooplankton • Niche – food stock for larger consumers • Example – krill; small crustaceans

  8. Ultraplankton • Ultraplankton (photosynthetic bacteria) • Extremely small plankton • Responsible for as much as 70% if the primary productivity near the ocean’s surface.

  9. Nekton • Description – larger, strong-swimming consumers • Niche – top consumers in the aquatic ecosystem • Example – fish, turtles, and whales

  10. Benthos • Description – bottom-dwelling creatures • Niche – primary consumers, decomposers • Example – barnacles, oysters, and lobsters

  11. Key Factors that Determine Biodiversity of Organisms in Aquatic Ecosystems • Temperature • Dissolved Oxygen (DO) • Sunlight Availability • Nutrient Availability • Turbidity • Cloudiness of the water • Can limit photosynthetic activity

  12. Aquatic Ecosystems & Biodiversity Marine Ecosystems(Ocean)

  13. Marine Ecosystems Natural Capital Ecological Services Economic Services Food Animal & Pet Feed Pharmaceuticals Harbors & Transportation Routes Costal habitats for humans Recreation Employment Oil & Natural Gas Minerals Building materials • Climate moderation • CO2 absorption • Nutrient Cycling • Waste Treatment • Reduce Storm impact • Habitat & Nursery areas • Biodiversity • Scientific Information

  14. Marine Ecosystems • Vertical Stratification • Light/temperature decrease with depth • Photic zone – light reaches (about 20m) • Littoral – shoreline • Intertidal – are exposed by low tide Continental Shelf

  15. Two Major Life Zones of Oceans Coastal • Interacts with land = affected by human activities • High productivity  10% of all oceans but 90% of all marine species • Plenty of sunlight and nutrients • Estuaries, coastal wetlands, mangroves, barrier islands, sandy shores, coral reefs Continental Shelf

  16. Two Major Life Zones of Oceans Open Ocean • Euphotic Zone: lighted, rich in phytoplankton, low nutrient levels (excpet during upwellings), high levels of DO • Bathyal Zone: dimly lit middle zone, no producers, zooplankton & small fish live here • Abyssal Zone: dark, cold, little DO, filter feeders, hydrothermal vents, low productivity

  17. Marine Ecosystems • Deep Ocean • Relatively low productivity • Around equator, many fish and phytoplankton • Sargasso Sea – blankets of brown algae support many diverse animals • Deep-sea thermal vents- chemosynthetic • Tubeworms, mussels, microbes • Thousands of microscopic organisms

  18. Marine Ecosystems • Coral Reefs: • High productivity/diversity • Home to ¼ all marine species • Protect shorelines • Shelter fish, worms, crustaceans, etc. • Shallow warm waters, sunlight • Dependent on photosynthetic algae • Coral Bleaching: warms waters are killing coral. • 1/3 destroyed by 2006, by 2030 60% expected to be gone

  19. Marine Ecosystems • Mangroves • Trees that grow in salt water • Calm, shallows, tropical coastlines • Stabilize shorelines • Nurseries for fish, shrimp, other commercial species • Clear-cut for timber, make room for fisheries • Mangroves provide protection for these fish they are being removed for. • Reduced catches, falling income

  20. Marine Ecosystems • Estuaries: • Bays where rivers empty into the sea • High productivity/diversity • “dead zones” : excess nutrients stimulate bacteria that uses O2 needed for other life • Tide-pools: • Depressions in rocky shoreline that flood at high tide, retain water at low tide • Specialized species • Starfish, sea anemone, ect.

  21. Marine Ecosystems • Barrier Islands • Low, narrow, sandy island parallel to the coastline • Protect inshore lagoons and salt marshes from storms, waves, tides • Critical in preserving coastlines, estuaries, and wetlands • Human occupation speed up erosion of barrier islands, vulnerable to storms

  22. Aquatic Ecology & Biodiversity Degrading marine ecosystems

  23. Degradation of Marine Ecosystems • Coastal development • Pollution • Overfishing • Fish trawlers • Invasive species • Climate change

  24. Invasive Species (HIPPCO) • Displace, cause extinction of native species & disrupt ecosystem services & human economies • Usually enters through ballast waters of ships • Ships still carry them if ballast waters are dumped before entering a port • Consumers promote • Undaria (aka wakame) • Lionfish

  25. Coastal Population Growth (HIPPCO) • ~45% of world’s population lived near or along coastlines • Increased growth = more boats, off-shore construction, oil/natural gas drilling • More collisions with boats & sea animals • Noise pollution • 80% ocean pollution comes from coastal activities

  26. Climate Change (HIPPCO) • Rising Sea-Levels • Destroy coral reefs • Swamp low-lying lands • Drown productive coastal wetlands • Destroy mangroves • Increase acidity = less sound absorption = more noise pollution

  27. Overfishing (HIPPCO) • 80% of some wild fish have been depleted in the last 10-15 years • Fishery: concentration of an aquatic species suitable for commercial harvesting in a given area • Fishprint: an area of ocean needed to sustain the fish consumption of the average person, nation, or world. • Global Fishprint is unstainable! • Overfishing leads to: • Most often commercial extinction (no longer profitable) • Destroys the marine food chain • Allows for invasive species to take over

  28. Industrial Fishing • Trawler fishing • Cod, flounder, shrimp, scallops • Dragging funnel shaped net along the ocean bottom • Scrapes & destroys ocean floor habitats • Purse-seine fishing • Tuna, mackerel, anchovies, herring • Kills other species (like dolphins) not being fished

  29. Industrial Fishing • Long-lining • Swordfish, tuna, sharks, halibut, cod • Use lines up to 100km long with 1000s of baited hooks • Kill endangered sea turtles, dolphins, seabirds • Drift-net fishing • Huge nets that hang up to 15m deep • Leads to overfishing of desired species and traps/kills many unwanted fish (bycatch) along with sea mammals, turtles, birds • 1/3 of all fishing weight is bycatch that is thrown overboard dead or dying

  30. Aquatic Ecosystems & Biodiversity Protecting Marine Biodiversity

  31. Difficulties in Protecting Marine Biodiversity • Ecological Footprint & Fishprint expanding so rapidly, it is hard to monitor their impacts • Most damage is not visible to most people • Most people view the ocean as an inexhaustible resource • Most of the world’s ocean lies outside of a country’s jurisdiction. • Open-access source = tragedy of the commons

  32. Laws & Treaties • 1975 Convention on International Trade in Endangered Species (CITES) • 1979 Global Treaty on Migratory Species • US Marine Mammal Protection Act of 1972 • US Whale Conservation & Preservation Act of 1976 • US Endangered Species Act of 1973 • 1995 International Convention on Biological Diversity

  33. International Whaling CommissionMoratorium on Commercial Whaling • Japan hunts and kills ~900 whales a year • On record for scientific purposes • Whale meat sold in restaurants and stores • Norway openly defies the moratorium and kills ~500-800 whales a year • Iceland kills ~150 whales a year • Traditional in their countries

  34. Other Protections • Educating about Economic Incentives • Sea turtles are worth more alive than dead (ecotourism) • Whale watching • Quotas & Governmental Permissions • Establishing Marine Protected Areas • 4000 worldwide • Only partially protected from human activity • Establishing a global network of marine reserves • Declared off-limits to any human activity to allow recovery

  35. Aquatic Ecosystems & Biodiversity Managing Fisheries

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