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Aquatic Biodiversity Chapter 8 Red Tide
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Core Case Study: Why Should We Care about Coral Reefs?
Biodiversity Formation – coral polyps + algae 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?
Degradation and decline Coastal development Pollution Overfishing Warmer ocean temperatures leading to coral bleaching Increasing ocean acidity
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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 (~70%)
Saltwater: global ocean divided into 4 areas Atlantic Pacific Arctic Indian Freshwater
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Most of the Earth Is Covered with Water
Aquatic life zones Saltwater: marine Oceans and estuaries Coastlands and shorelines Coral reefs Mangrove forests (see Mangrove Adventure video in Ch folder) Freshwater Lakes Rivers and streams Inland wetlands
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The Ocean Planet
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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 Phyto: plant, plankton: difting Primary producers Zooplankton – zoo: animal Ultraplankton photosynthetic bacteria 70% of primary productivity near ocean surface Nekton – strong swimmers Benthos – bottom dwellers 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 content Availability of food Availability of light and nutrients needed for photosynthesis in the euphotic, or photic, zone Light can be reduced by turbidity – cloudiness caused by algal blooms or sediment
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Testing turbidity
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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 – 10% of ocean, 90% of marine species! Usually high NPP – due to ample sunlight and nutrients Open sea – nutrients in short supply Euphotic zone: 40% of the world’s photosynthesis! 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
Estuaries and coastal wetlands - high nutrient input from rivers 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 Toxic pollutants Excess plant nutrients Sediments Absorb other pollutants Provide food, timber, fuelwood, and habitats Reduce storm damage and coast erosion
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View of an Estuary from Space
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Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area
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Rocky and Sandy Shores Host Different Types of Organisms
Intertidal zone – tides rise and fall every 6 hours Rocky shores Sandy shores: barrier beaches Organism adaptations necessary to deal with daily salinity and moisture changes – hold onto something, protective shell, dig into mud Importance of sand dunes – plant roots hold sand in place. They protect inland areas from the sea.
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Living between the Tides
Rocky Shore Beach Sea star Hermit crab Shore crab High tide Periwinkle Sea urchin Anemone Mussel Low tide Sculpin Barnacles Kelp Sea lettuce Monterey flatworm Nudibranch Beach flea Peanut worm Tiger beetle Barrier Beach Blue crab Clam Dwarf olive High tide Sandpiper Ghost shrimp Silversides Low tide Mole shrimp White sand macoma Sand dollar Moon snail Figure 8.9 Living between the tides. Some organisms with specialized niches found in various zones on rocky shore beaches (top) and barrier or sandy beaches (bottom). Organisms are not drawn to scale. Living between the Tides Stepped Art Fig. 8-9, p. 169
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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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Natural Capital: Components and Interactions in a Coral Reef Ecosystem
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The Open Sea and Ocean Floor Host a Variety of Species
Vertical zones of the open sea Euphotic zone – Eu:good, phot: light Bathyal zone - dim light Abyssal zone: receives marine snow Deposit feeders – eat mud (worms) Filter feeders - filter water (shellfish, sponges) Upwellings – bring nutrients up from bottom, caused by winds and ocean currents Primary productivity and NPP – low per unit area, but since area is so large, large overall
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Littoral – between high and low water mark in rivers, lakes, seas
And areas near shorelines Abyssal– sea floor Hadal – (like Hades) – deep sea trenches
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http://www. youtube. com/watch. v=8101vCjM7nY http://www. youtube
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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? Pros: Cons:
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Chesapeake Bay
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8-4 Why Are Freshwater Ecosystems Important?
Concept 8-4 Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.
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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
Formation of lakes Glaciation Crustal displacement Volcanic activity Four zones based on depth and distance from shore Littoral zone – near shore Limnetic zone – open water, top layer Profundal zone – too dark for photosynthesis Benthic zone – bottom, decomposers and detritivores live here
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NATURAL CAPITAL Freshwater Systems Ecological Services
Economic Services Climate moderation Food Nutrient cycling Drinking water Waste treatment Irrigation water Flood control Hydroelectricity Groundwater recharge Figure 8.14 Major ecological and economic services provided by freshwater systems (Concept 8-4). Question: Which two ecological services and which two economic services do you think are the most important? Why? Habitats for many species Transportation corridors Genetic resources and biodiversity Recreation Scientific information Employment Fig. 8-14, p. 174
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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 Steep banks, deep water Eutrophic lakes High levels of nutrients and high NPP Mesotrophic lakes – (meso = middle) Cultural eutrophication leads to hypereutrophic lakes
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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 – discuss combined sewer overflows 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 Waterfall Lake Glacier Rain and snow Rapids Source Zone Transition Zone Tributary Flood plain Oxbow lake Salt marsh Delta Deposited sediment Ocean Water Sediment Floodplain Zone Figure 8.17 Three zones in the downhill flow of water: source zone containing mountain (headwater) streams; transition zone containing wider, lower-elevation streams; and floodplain zone containing rivers, which empty into the ocean. Stepped Art Fig. 8-17, p. 176
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Case Study: Dams, Deltas, Wetlands, Hurricanes, and New Orleans
Coastal deltas, mangrove forests, and coastal wetlands: 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, (U.S.) 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
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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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.
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Human Activities Are Disrupting and Degrading Freshwater Systems
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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(first video – ocean acidification.)
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