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 Covers 71% of the Earth’s surface Freshwater- covers 2.2% of the Earth’s surface

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

The Ocean Planet

Distribution of the World’s Major Saltwater and Freshwater Sources

Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water (1) Plankton- free floating Phytoplankton- producers Zooplankton- consumers Ultraplankton- photosynthetic bacteria Nekton- free swimming- fish, turtles, whales Benthos- bottom dwellers Decomposers- mostly bacteria

dinoflagellate radiolarian

Shrimp larva Anemone larva Worm larva Worm larva copepod

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 Depth of the euphotic zone can be decreased by turbidity- (cloudiness)

Ted video

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.

Major Ecological and Economic Services Provided by Marine Systems

Oceans Provide Important Ecological and Economic Resources Reservoirs of diversity in three major life zones Coastal zone- warm, nutrient rich, shallow water from high tide mark to the edge of the continental shelf Makes up less than 10% of ocean area, but holds 90% of species Usually high NPP- due to high nutrients and sunlight Open sea- Ocean bottom

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) Estuaries and coastal wetlands(where fresh and salt water combine) 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

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- area of shoreline between high and low tide Rocky shores- lots of species, seasonal changes in salinity, temperature and water flow Sandy shores: barrier beaches Organism adaptations necessary to deal with daily salinity and moisture changes- digging, burrowing, tunneling Importance of sand dunes- protect from erosion

Living between the Tides

Primary and Secondary Dunes

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

The Open Sea and Ocean Floor Host a Variety of Species Vertical zones of the open sea Euphotic zone- brightly lit- phytoplankton carry out 40% of the worlds photosynthesis Bathyal zone- dimly lit middle zone Abyssal zone: receives marine snow Deposit feeders Filter feeders Upwellings- bring nutrients from the bottom to the surface Primary productivity and NPP- low per unit area- high NPP contribution for the earth

Animation: Ocean provinces

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? 40

Chesapeake Bay

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- top, near the shore, full light, Limnetic zone- open, sunlit, away from shore Profundal zone-deep open water, too dark for photosynthesis Benthic zone-bottom- decomposers, detritus feeders, some fish

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

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 Deep lakes, steep sides, 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

Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans Surface water- precip that does not sink or evaporate Runoff- surface water that flows into streams Watershed, drainage basin- land area that delivers run-off, sediment and dissolved substances to a stream

Three aquatic life zones Source zone-mountain head waters, shallow, swiftly moving streams- cold, clear- lots of dissolved oxygen- not very productive due to low nutrients Transition zone- wider, deeper, warmer streams that flow down gentler slopes, more turbid- less DO- more productivity

Floodplain zone- wide, deep rivers that flow across flat valleys, supports large populations of producers- full of silt-

Three Zones in the Downhill Flow of Water

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- dominated by grasses and few trees Swamps- trees and shrubs Prairie potholes-depressions carved out by ancient glaciers Floodplains- receive excessive water during heavy rains and floods 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: Trophic natures of lakes

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 dams and canals on rivers flood control levees and dikes along rivers pollutants from cities and farms on rivers 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