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Aquatic Biodiversity Chapter 8
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Core Case Study: Why Should We Care about Coral Reefs?
Biodiversity Formation 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
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Core Case Study: Why Should We Care about Coral Reefs? (2)
Degradation and decline Coastal development Pollution Overfishing (know different techniques) Warmer ocean temperatures leading to coral bleaching Increasing ocean acidity (know pH ranges)
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A Healthy Coral Reef in the Red Sea
Dead coral reef
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8-1 What Is the General Nature of Aquatic Systems?
Concept 8-1A Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface with oceans dominating the planet. Concept 8-1B 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.
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Most of the Earth Is Covered with Water
Aquatic life zones Saltwater: marine Oceans and estuaries Coastlands /shorelines Coral reefs Mangrove forests Freshwater Lakes Rivers and streams Inland wetlands Saltwater: global ocean divided into 4 areas Atlantic Pacific Arctic Indian
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The Ocean Planet
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Land–ocean hemisphere
Figure 8.2 The ocean planet. The salty oceans cover 71% of the earth’s surface. Almost all of the earth’s water is in the interconnected oceans, which cover 90% of the planet’s mostly ocean hemisphere (left) and half of its land–ocean hemisphere (right). Freshwater systems cover less than 2.2% of the earth’s surface (Concept 8-1A). Ocean hemisphere Land–ocean hemisphere Fig. 8-2, p. 163
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Distribution of the World’s Major Saltwater and Freshwater Sources
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Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water
Plankton Phytoplankton Zooplankton Ultraplankton Photo. Bacteria (70% O2) Nekton Benthos Decomposers
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Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water
Key factors in the distribution of organisms Temperature Dissolved oxygen (DO) content Availability of food Availability of light and nutrients needed for photosynthesis in the euphotic/photic zone . --turbidity effect light availability -- nutrients such as CO2, nitogen and phosphorus
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8-2 Why Are Marine Aquatic Systems Important?
Concept 8-2 Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services.
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Oceans Provide Important Ecological and Economic Resources
Reservoirs of diversity in three major life zones Coastal zone Usually high NPP; unlike pelagic ocean zones Open sea Ocean bottom
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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 Figure 8.4 Major ecological and economic services provided by marine systems (Concept 8-2). Question: Which two ecological services and which two economic services do you think are the most important? Why? Recreation Habitats and nursery areas Employment Oil and natural gas Genetic resources and biodiversity Minerals Scientific information Building materials Fig. 8-4, p. 165
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Natural Capital: Major Life Zones and Vertical Zones in an Ocean
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Estuaries and Coastal Wetlands Are Highly Productive
River mouths Inlets Bays Sounds Salt marshes Mangrove forests Seagrass Beds Support a variety of marine species Stabilize shorelines Reduce wave impact
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Estuaries and Coastal Wetlands Are Highly Productive
Important ecological and economic services Coastal aquatic systems maintain water quality by filtering : 1)Toxic pollutants,2)Excess plant nutrients, 3)Sediments Absorb other pollutants Provide food, timber, fuelwood, and habitats Reduce storm damage and coast erosion
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Some Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area
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Mangrove Forest in Daintree National Park in Queensland, Australia
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Rocky and Sandy Shores Host Different Types of Organisms
Intertidal zone Rocky shores Sandy shores: barrier beaches (Padre Island) Organism adaptations necessary to deal with daily salinity and moisture changes Importance of sand dunes
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Living between the Tides
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Primary and Secondary Dunes
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Coral Reefs Are Amazing Centers of Biodiversity
Marine equivalent of tropical rain forests Habitats for one-fourth of all marine species
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Green sea turtle Banded coral shrimp Symbiotic algae
Gray reef shark Sea nettle Green sea turtle Parrot fish Blue tang Fairy basslet Sergeant major Algae Brittle star Hard corals Banded coral shrimp Phytoplankton Coney Symbiotic algae Coney Zooplankton Figure 8.11 Natural capital: some components and interactions in a coral reef ecosystem. When these organisms die, decomposers break down their organic matter into minerals used by plants. Colored arrows indicate transfers of matter and energy between producers, primary consumers (herbivores), secondary or higher-level consumers (carnivores), and decomposers. Organisms are not drawn to scale. Blackcap basslet Sponges Moray eel Bacteria Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All consumers and producers to decomposers Fig. 8-11, p. 171
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The Open Sea and Ocean Floor Host a Variety of Species
Vertical zones of the open sea Euphotic zone Bathyal zone Abyssal zone: receives marine snow Deposit feeders Filter feeders Upwellings Primary productivity and NPP
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8-3 How Have Human Activities Affected Marine Ecosystems?
Concept 8-3 Human activities threaten aquatic biodiversity and disrupt ecological and economic services provided by saltwater systems.
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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
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Case Study: The Chesapeake Bay—an Estuary in Trouble
Largest estuary in the US; polluted since 1960 Population increased Point and nonpoint sources raised pollution Phosphate and nitrate levels too high Overfishing 1983: Chesapeake Bay Program Update on recovery of the Bay Should we introduce an Asian oyster?
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Chesapeake Bay Watershed
(Hypoxia)
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FRESHWATER
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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
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Water Stands in Some Freshwater Systems and Flows in Others (2)
Formation of lakes Four zones based on depth and distance from shore Littoral zone Limnetic zone Profundal zone Benthic zone
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Distinct Zones of Life in a Fairly Deep Temperate Zone Lake
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Some Lakes Have More Nutrients Than Others
Oligotrophic lakes Low levels of nutrients and low NPP (clear lakes like Tahoe or Crater Lake) Eutrophic lakes High levels of nutrients and high NPP due to high levels of plant/algae Mesotrophic lakes (most lakes) Cultural eutrophication if caused by man – usually runoff containing nitrogen fertilizers.
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The Effect of Nutrient Enrichment on a Lake
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Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans
Surface water Runoff Watershed, drainage basin Three aquatic life zones Source zone Transition zone Floodplain zone
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Three Zones in the Downhill Flow of Water
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Case Study: Dams, Deltas, Wetlands, Hurricanes, and New Orleans
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
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New Orleans, Louisiana and Hurricane Katrina
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Projection of New Orleans if the Sea Level Rises 0.9 Meter
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Freshwater Inland Wetlands Are Vital Sponges
Marshes Swamps Prairie potholes Floodplains Arctic tundra in summer
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Freshwater Inland Wetlands Are Vital Sponges (2)
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
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LAKE TURN OVER – IT’S NATURAL
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8-5 How Have Human Activities Affected Freshwater Ecosystems?
Concept 8-5 Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands. 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
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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
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