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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. Gray reef shark Sea nettle Green sea turtle Blue tang Fairy basslet Parrot fish Brittle star Sergeant major Algae Hard corals Banded coral shrimp Phytoplankton Coney Symbiotic algae Blackcap basslet Zooplankton Sponges Moray eel Bacteria Secondary to higher-level consumer Producer to primary consumer Primary to secondary consumer All producers and consumers to decomposers Fig. 8-12, p. 177

  20. 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

  21. 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.

  22. Tide Pools Rocky Shore Beach Hermit crab Shore crab Sea star High tide Periwinkle Sea urchin Anemone Mussel Low tide Sculpin Barnacles Kelp Sea lettuce Monterey flatworm Nudibranch Fig. 8-11a, p. 176

  23. 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

  24. Barrier Islands Beach flea Barrier Beach Peanut worm Tiger beetle Clam Blue crab Dwarf olive High tide Sandpiper Ghost shrimp Silversides Low tide Mole shrimp White sand macoma Sand dollar Moon snail Fig. 8-11b, p. 176

  25. Aquatic Ecology & Biodiversity Degrading marine ecosystems

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

  27. 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

  28. 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

  29. 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

  30. 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

  31. 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

  32. 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

  33. Trawler fishing Sonar Drift-net fishing Long line fishing Float Buoy lines with hooks Fish caught by gills Fish farming in cage Spotter airplane Purse-seine fishing Deep sea aquaculture cage Stepped Art Fig. 11-8, p. 259

  34. Aquatic Ecosystems & Biodiversity Protecting Marine Biodiversity

  35. 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

  36. 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

  37. 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

  38. 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

  39. Aquatic Ecosystems & Biodiversity Managing Fisheries

  40. Solutions Managing Fisheries Bycatch Fishery Regulations Use nets that allow escape of smaller fish Set low catch limits Improve monitoring and enforcement Use net escape devices for seabirds and sea turtles Economic Approaches Reduce or eliminate fishing subsidies Aquaculture Restrict coastal locations of fish farms Improve pollution control Certify sustainable fisheries Protect Areas Establish no-fishing areas Nonnative Invasions Establish more marine protected areas Kill or filter organisms from ship ballast water Consumer Information Dump ballast water at sea and replace with deep-sea water Label sustainably harvested fish Publicize overfished and threatened species Fig. 11-11, p. 267

  41. Aquatic Ecosystems & Biodiversity Freshwater Ecosystems

  42. Why Are Freshwater Ecosystems Important? • Freshwater ecosystems provide major ecological and economic services, and are irreplaceable reservoirs of biodiversity.

  43. 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

  44. Freshwater Ecosystems Vertical Stratification • 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

  45. Freshwater Ecosystems Vertical Stratification • 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

  46. Lakes • 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

  47. The Effect of Nutrient Enrichment on a Lake Eutrophication: Changes that take place after a water systems receives excess nutrients (usually nitrates & phosphates) from runoff. Eutrophication Fig. 8-17, p. 182

  48. Freshwater Ecosystems • Lakes • Vertical zones • Open water: plankton, microscopic plants, animals, & protists, water striders, mosquitoes • Water column – variety of fish • Benthos: bottom, snails, worms, fish, other organisms • Littoral: plants • Conditions that affect lake productivity • Nutrient availability, nitrates, phosphates • Suspended matter, silt, affects depth of light • Depth • Temperature • Currents • Bottom: muddy, sandy, rocky floor • Connections to other ecosystems

  49. Freshwater Ecosystems • Lakes

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