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Chapter 8: Aquatic Biodiversity

Coral Reefs

Ecological & 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

Degradation and Decline

  • Coastal development

  • Pollution

  • Overfishing

  • Warmer ocean temperatures leading to coral bleaching→ Kill algae and thus the polyps

  • Increasing ocean acidity

What Is the General Nature of Aquatic Systems?

Most of the Earth Is Covered with Water

  • Saltwater includes;

    • Atlantic

    • Pacific

    • Arctic

    • Indian

  • Freshwater: Any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids.

Aquatic Life Zones

  • Saltwater life zones (marine life zones): Oceans, estuaries, coastlands, shorelines, coral reefs, and mangrove forests.

  • Freshwater life zones: Lakes, rivers, streams, and inland wetlands

Aquatic Species

  • Plankton→ Free floating creatures

    • Phytoplankton: Primary producers for most aquatic food webs

    • Zooplankton: Primary and secondary consumers. Single-celled to large invertebrates like jellyfish

    • Ultraplankton: Tiny photosynthetic bacteria

  • Nekton are strong swimmers

    • Fish, turtles, whales, etc.

  • Benthos: Bottom dwellers

    • Oysters, sea stars, clams, lobsters, crabs, etc.

  • Decomposers: Mostly bacteria

Key Factors That Determine Types & Numbers of Organisms

  • Critical factors in the distribution of organisms

    • Temperature

    • Dissolved oxygen content

    • Availability of food

    • Availability of light and nutrients needed for photosynthesis in the eutrophic (photic) zone

  • Turbidity: Degree of cloudiness in the water, inhibits photosynthesis

Why Are Marine Aquatic Systems Important?

Oceans Provide Vital Ecological and Economic Resources

  • Reservoirs of diversity in three major life zones

    • Coastal zone: Warm, nutrient-rich, shallow. Shore to the edge of a continent shelf.

    • Open sea

    • Ocean bottom

Major Ecological and Economic Services Provided by Marine Systems

  • Ecological Services

    • Climate moderation

    • CO2 absorption

    • Nutrient cycling

    • Waste treatment

    • Reduced storm impact (mangroves, barrier islands, coastal wetlands

    • Habitats and nursery areas

    • Genetic Resources and biodiversity

    • Scientific information

  • Economic Services

    • Food

    • Animals and pet feed

    • Pharmaceuticals

    • Harbors and transportation routes

    • Coastal habitats for humans

    • Recreation

    • Employment

    • Oil and natural gas

    • Minerals

    • Building materials

Estuaries and Coastal Wetlands

  • Estuaries/Coastal Wetlands: Where rivers meet the sea and seawater mixes with freshwater (ex. river mouths, inlets, bays, sounds, salt marshes, and mangrove forests.)

    • Very productive ecosystems→ high nutrient levels

  • Seagrass Beds: Grow underwater in shallow areas, support a variety of marine species, stabilize shorelines, and reduce wave impact.

  • Mangrove forests: Along tropical and subtropical coastlines, 69 different tree species grow in saltwater

Rocky and Sandy Shores Host Different Types of Organisms

  • Intertidal zone: Rocky shores or sandy shores which have barrier beaches

Three Zones of the Ocean

  1. Euphotic zone: Phytoplankton, nutrient level low, dissolved oxygen levels high.

  2. Bathyal zone: Dimly lit, zooplankton and smaller fishes

  3. Abyssal zone: Dark and cold, high levels of nutrients, little dissolved oxygen, deposit feeders, filter feeders

How Have Human Activities Affected Marine Ecosystems?

Major threats to marine systems

  • Major threats to marine systems

  • Coastal development

  • Overfishing

  • Use of fishing trawlers

  • Runoff of nonpoint source pollution

  • Point source pollution: Discharge pollutants at specific locations

  • Habitat destruction

  • Introduction of invasive species

  • Climate change from human activities

  • Pollution of coastal wetlands and estuaries

Why Are Freshwater Ecosystems Important?

Water Stands in Some Freshwater Systems and Flows in Others

  • Standing (lentic) bodies of freshwater: Lakes, ponds, inland wetlant=ds

  • Flowing (lotic) systems of freshwater: Streams and rivers

  • Littoral zone: Near shore where rooted plants grow, high biodiversity,

    • Turtles, frogs, crayfish, and some fish

  • Limnetic zone: Sunlight area away from shore, main photosynthetic zone, some larger fish

  • Profundal zone: Deepwater too dark for photosynthesis, low oxygen levels, with some fish

  • Benthic zone: Decomposers, detritus feeders, and some fish, nourished primarily by dead matter

Major Services Provided by Freshwater Systems

  • Ecological Services:

    • Climate moderation

    • Nutrient cycling

    • Waste treatment

    • Flood control

    • Groundwater recharge

    • Habitats for many species

    • Genetic resources and biodiversity

    • Scientific information

  • Economic Services:

    • Food

    • Drinking water

    • Irrigation water

    • Hydroelectricity

    • Transportation corridors

    • Recreation

    • Employment

Some Lakes Have More Nutrients Than Others

  • Oligotrophic Lakes: Low levels of nutrients and low NPP with very clear water

  • Eutrophic Lakes: High levels of nutrients and high NPP and murky water with high turbidity

  • Mesotrophic Lakes: Commonly clear water lakes and ponds with beds of submerged aquatic plants and medium levels of nutrients

  • Cultural Eutrophication: This occurs when sewage, detergents, fertilizers, and other nutrient sources are introduced into the ecosystem as a result of human water pollution, accelerating the aging process.

Chapter 8: Aquatic Biodiversity

Coral Reefs

Ecological & 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

Degradation and Decline

  • Coastal development

  • Pollution

  • Overfishing

  • Warmer ocean temperatures leading to coral bleaching→ Kill algae and thus the polyps

  • Increasing ocean acidity

What Is the General Nature of Aquatic Systems?

Most of the Earth Is Covered with Water

  • Saltwater includes;

    • Atlantic

    • Pacific

    • Arctic

    • Indian

  • Freshwater: Any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids.

Aquatic Life Zones

  • Saltwater life zones (marine life zones): Oceans, estuaries, coastlands, shorelines, coral reefs, and mangrove forests.

  • Freshwater life zones: Lakes, rivers, streams, and inland wetlands

Aquatic Species

  • Plankton→ Free floating creatures

    • Phytoplankton: Primary producers for most aquatic food webs

    • Zooplankton: Primary and secondary consumers. Single-celled to large invertebrates like jellyfish

    • Ultraplankton: Tiny photosynthetic bacteria

  • Nekton are strong swimmers

    • Fish, turtles, whales, etc.

  • Benthos: Bottom dwellers

    • Oysters, sea stars, clams, lobsters, crabs, etc.

  • Decomposers: Mostly bacteria

Key Factors That Determine Types & Numbers of Organisms

  • Critical factors in the distribution of organisms

    • Temperature

    • Dissolved oxygen content

    • Availability of food

    • Availability of light and nutrients needed for photosynthesis in the eutrophic (photic) zone

  • Turbidity: Degree of cloudiness in the water, inhibits photosynthesis

Why Are Marine Aquatic Systems Important?

Oceans Provide Vital Ecological and Economic Resources

  • Reservoirs of diversity in three major life zones

    • Coastal zone: Warm, nutrient-rich, shallow. Shore to the edge of a continent shelf.

    • Open sea

    • Ocean bottom

Major Ecological and Economic Services Provided by Marine Systems

  • Ecological Services

    • Climate moderation

    • CO2 absorption

    • Nutrient cycling

    • Waste treatment

    • Reduced storm impact (mangroves, barrier islands, coastal wetlands

    • Habitats and nursery areas

    • Genetic Resources and biodiversity

    • Scientific information

  • Economic Services

    • Food

    • Animals and pet feed

    • Pharmaceuticals

    • Harbors and transportation routes

    • Coastal habitats for humans

    • Recreation

    • Employment

    • Oil and natural gas

    • Minerals

    • Building materials

Estuaries and Coastal Wetlands

  • Estuaries/Coastal Wetlands: Where rivers meet the sea and seawater mixes with freshwater (ex. river mouths, inlets, bays, sounds, salt marshes, and mangrove forests.)

    • Very productive ecosystems→ high nutrient levels

  • Seagrass Beds: Grow underwater in shallow areas, support a variety of marine species, stabilize shorelines, and reduce wave impact.

  • Mangrove forests: Along tropical and subtropical coastlines, 69 different tree species grow in saltwater

Rocky and Sandy Shores Host Different Types of Organisms

  • Intertidal zone: Rocky shores or sandy shores which have barrier beaches

Three Zones of the Ocean

  1. Euphotic zone: Phytoplankton, nutrient level low, dissolved oxygen levels high.

  2. Bathyal zone: Dimly lit, zooplankton and smaller fishes

  3. Abyssal zone: Dark and cold, high levels of nutrients, little dissolved oxygen, deposit feeders, filter feeders

How Have Human Activities Affected Marine Ecosystems?

Major threats to marine systems

  • Major threats to marine systems

  • Coastal development

  • Overfishing

  • Use of fishing trawlers

  • Runoff of nonpoint source pollution

  • Point source pollution: Discharge pollutants at specific locations

  • Habitat destruction

  • Introduction of invasive species

  • Climate change from human activities

  • Pollution of coastal wetlands and estuaries

Why Are Freshwater Ecosystems Important?

Water Stands in Some Freshwater Systems and Flows in Others

  • Standing (lentic) bodies of freshwater: Lakes, ponds, inland wetlant=ds

  • Flowing (lotic) systems of freshwater: Streams and rivers

  • Littoral zone: Near shore where rooted plants grow, high biodiversity,

    • Turtles, frogs, crayfish, and some fish

  • Limnetic zone: Sunlight area away from shore, main photosynthetic zone, some larger fish

  • Profundal zone: Deepwater too dark for photosynthesis, low oxygen levels, with some fish

  • Benthic zone: Decomposers, detritus feeders, and some fish, nourished primarily by dead matter

Major Services Provided by Freshwater Systems

  • Ecological Services:

    • Climate moderation

    • Nutrient cycling

    • Waste treatment

    • Flood control

    • Groundwater recharge

    • Habitats for many species

    • Genetic resources and biodiversity

    • Scientific information

  • Economic Services:

    • Food

    • Drinking water

    • Irrigation water

    • Hydroelectricity

    • Transportation corridors

    • Recreation

    • Employment

Some Lakes Have More Nutrients Than Others

  • Oligotrophic Lakes: Low levels of nutrients and low NPP with very clear water

  • Eutrophic Lakes: High levels of nutrients and high NPP and murky water with high turbidity

  • Mesotrophic Lakes: Commonly clear water lakes and ponds with beds of submerged aquatic plants and medium levels of nutrients

  • Cultural Eutrophication: This occurs when sewage, detergents, fertilizers, and other nutrient sources are introduced into the ecosystem as a result of human water pollution, accelerating the aging process.

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