Aquatic Biodiversity Chapter 8

Core Case Study: Why Should We Care about Coral Reefs? (1) 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

Core Case Study: Why Should We Care about Coral Reefs? (2) Degradation and decline Coastal development Pollution Overfishing Warmer ocean temperatures leading to coral bleaching Increasing ocean acidity

A Healthy Coral Reef in the Red Sea

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.

Most of the Earth Is Covered with Water (1) Saltwater: global ocean divided into 4 areas Atlantic Pacific Arctic Indian Freshwater

Most of the Earth Is Covered with Water (2) Aquatic life zones Saltwater: marine Oceans and estuaries Coastlands and shorelines Coral reefs Mangrove forests Freshwater Lakes Rivers and streams Inland wetlands

The Ocean Planet

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

Distribution of the World’s Major Saltwater and Freshwater Sources

Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (1) Plankton Phytoplankton Zooplankton Ultraplankton Nekton Benthos Decomposers

Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (2) 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

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.

Oceans Provide Important Ecological and Economic Resources Reservoirs of diversity in three major life zones Coastal zone Usually high NPP Open sea Ocean bottom

Major Ecological and Economic Services Provided by Marine Systems

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

Natural Capital: Major Life Zones and Vertical Zones in an Ocean

Euphotic Zone Continental shelf High tide Low tide Sun Depth in meters Coastal Zone Open Sea Sea level Photosynthesis 50 Euphotic Zone Estuarine Zone 100 Continental shelf 200 500 Bathyal Zone Twilight 1,000 1,500 2,000 Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline . Abyssal Zone 3,000 Figure 8.5 Natural capital: major life zones and vertical zones (not drawn to scale) in an ocean. Actual depths of zones may vary. Available light determines the euphotic, bathyal and abyssal zones. Temperature zones also vary with depth, shown here by the red curve. Question: How is an ocean like a rain forest? (Hint: see Figure 7-17, p. 156.) Darkness 4,000 5,000 10,000 5 10 15 20 25 30 Water temperature (°C) Fig. 8-5, p. 166

Estuaries and Coastal Wetlands Are Highly Productive (1) River mouths Inlets Bays Sounds Salt marshes Mangrove forests Seagrass Beds Support a variety of marine species Stabilize shorelines Reduce wave impact

Estuaries and Coastal Wetlands Are Highly Productive (2) 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

View of an Estuary from Space

Some Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area

Short-billed dowitcher Herring gulls Peregrine falcon Snowy egret Cordgrass Short-billed dowitcher Phytoplankton Marsh periwinkle Smelt Figure 8.7 Some components and interactions in a salt marsh ecosystem in a temperate area such as the United States. When these organisms die, decomposers break down their organic matter into minerals used by plants. Colored arrows indicate transfers of matter and energy between consumers (herbivores), secondary or higher-level consumers (carnivores), and decomposers. Organisms are not drawn to scale. The photo shows a salt marsh in Peru. Zooplankton and small crustaceans Soft-shelled clam Bacteria Clamworm Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All consumers and producers to decomposers Fig. 8-7a, p. 167

Figure 8.7 Some components and interactions in a salt marsh ecosystem in a temperate area such as the United States. When these organisms die, decomposers break down their organic matter into minerals used by plants. Colored arrows indicate transfers of matter and energy between consumers (herbivores), secondary or higher-level consumers (carnivores), and decomposers. Organisms are not drawn to scale. The photo shows a salt marsh in Peru. Fig. 8-7b, p. 167

Mangrove Forest in Daintree National Park in Queensland, Australia

Rocky and Sandy Shores Host Different Types of Organisms Intertidal zone Rocky shores Sandy shores: barrier beaches Organism adaptations necessary to deal with daily salinity and moisture changes Importance of sand dunes

Living between the Tides

Rocky Shore Beach Barrier Beach Sea star Hermit crab Shore crab High tide Periwinkle Sea urchin Anemone Mussel Low tide Sculpin Barnacles Kelp Sea lettuce Rocky Shore Beach Monterey flatworm Beach flea Nudibranch Peanut worm Tiger beetle Blue crab Clam Dwarf olive High tide 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. Sandpiper Ghost shrimp Silversides Low tide Mole shrimp Barrier Beach White sand macoma Sand dollar Moon snail Fig. 8-9, p. 169

Rocky Shore Beach Barrier 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. Stepped Art Fig. 8-9, p. 169

Primary and Secondary Dunes

Limited recreation and walkways Most suitable for development Ocean Beach Primary Dune Trough Secondary Dune Back Dune Bay or Lagoon Recreation, no building Walkways, no building Limited recreation and walkways Walkways, no building Most suitable for development Recreation Bay shore Grasses or shrubs Taller shrubs Figure 8.10 Primary and secondary dunes on gently sloping sandy barrier beaches help protect land from erosion by the sea. The roots of grasses that colonize the dunes hold the sand in place. Ideally, construction is allowed only behind the second strip of dunes, and walkways to the ocean beach are built so as not to damage the dunes. This helps to preserve barrier beaches and to protect buildings from damage by wind, high tides, beach erosion, and flooding from storm surges. Such protection is rare in some coastal areas because the short-term economic value of oceanfront land is considered much higher than its long-term ecological value. Rising sea levels from global warming may put many barrier beaches under water by the end of this century. Question: Do you think that the long and short-term ecological values of oceanfront dunes outweigh the short-term economic value of removing them for coastal development? Explain. Taller shrubs and trees Fig. 8-10, p. 170

Coral Reefs Are Amazing Centers of Biodiversity Marine equivalent of tropical rain forests Habitats for one-fourth of all marine species

Natural Capital: Some Components and Interactions in a Coral Reef Ecosystem

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

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

Animation: Ocean provinces

Video: Elephant seals

Video: Florida reefs

Video: Giant clam

Video: Reef fish (Bahamas)

Video: Schooling fish

Video: Sea anemones

Video: Sea lions

Video: Sting rays

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.

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

Case Study: The Chesapeake Bay—an Estuary in Trouble (1) Largest estuary in the US; polluted since 1960 Population increased Point and nonpoint sources raised pollution Phosphate and nitrate levels too high

Case Study: The Chesapeake Bay—an Estuary in Trouble (2) Overfishing 1983: Chesapeake Bay Program Update on recovery of the Bay Should we introduce an Asian oyster? 48

Chesapeake Bay

Video: ABC News: Beach pollution

8-4 Why Are Freshwater Ecosystems Important? Concept 8-4 Freshwater ecosystems provide major ecological and economic services and are irreplaceable reservoirs of biodiversity.

Water Stands in Some Freshwater Systems and Flows in Others (1) Standing (lentic) bodies of freshwater Lakes Ponds Inland wetlands Flowing (lotic) systems of freshwater Streams Rivers

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

Major Ecological and Economic Services Provided by Freshwater Systems

NATURAL CAPITAL Freshwater Systems Ecological Services Economic Services Climate moderation Food Nutrient cycling Drinking water Waste treatment Irrigation water Flood control Hydroelectricity 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? Groundwater recharge Habitats for many species Transportation corridors Genetic resources and biodiversity Recreation Scientific information Employment Fig. 8-14, p. 174

Distinct Zones of Life in a Fairly Deep Temperate Zone Lake

Sunlight Blue-winged teal Painted turtle Green frog Muskrat Pond snail Littoral zone Plankton Figure 8.15 Distinct zones of life in a fairly deep temperate zone lake. See an animation based on this figure at CengageNOW. Question: How are deep lakes like tropical rain forests? (Hint: See Figure 7-17, p. 156) Limnetic zone Diving beetle Profundal zone Northern pike Benthic zone Yellow perch Bloodworms Fig. 8-15, p. 175

Some Lakes Have More Nutrients Than Others Oligotrophic lakes Low levels of nutrients and low NPP Eutrophic lakes High levels of nutrients and high NPP Mesotrophic lakes Cultural eutrophication leads to hypereutrophic lakes

The Effect of Nutrient Enrichment on a Lake

Figure 8.16 The effect of nutrient enrichment on a lake. Crater Lake in the U.S. state of Oregon (left) is an example of an oligotrophic lake that is low in nutrients. Because of the low density of plankton, its water is quite clear. The lake on the right, found in western New York State, is a eutrophic lake. Because of an excess of plant nutrients, its surface is covered with mats of algae and cyanobacteria. Stepped Art Fig. 8-16a, p. 175

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

Three Zones in the Downhill Flow of Water

Lake Rain and snow Glacier Rapids Waterfall Tributary Flood plain Oxbow lake Salt marsh Deposited sediment Delta Ocean Source Zone Transition 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. Water Sediment Floodplain Zone Fig. 8-17, p. 176

Lake Rain and snow Glacier Rapids Waterfall Tributary Flood plain 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

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

New Orleans, Louisiana, (U.S.) and Hurricane Katrina

Projection of New Orleans if the Sea Level Rises 0.9 Meter

Freshwater Inland Wetlands Are Vital Sponges (1) Marshes Swamps Prairie potholes Floodplains Arctic tundra in summer

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

Active Figure: Lake zonation

Animation: Lake turnover

Animation: Trophic natures of lakes

Video: River flyover

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.

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

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