Chapter 8Chapter 8

Aquatic Biodiversity

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

Fig. 6-1a, p. 126

Core Case Study:Why Should We Care About Coral Reefs?

Core Case Study:Why Should We Care About Coral Reefs?

• Coral reefs form in clear, warm coastal waters of the tropics and subtropics.– Formed by massive

colonies of polyps.

Figure 8-1Figure 8-1

Core Case Study:Why Should We Care About Coral Reefs?

Core Case Study:Why Should We Care About Coral Reefs?• Help moderate atmospheric temperature by

removing CO2 from the atmosphere.

• Act as natural barriers that help protect 14% of the world’s coastlines from erosion by battering waves and storms.

• Provide habitats for a variety of marine organisms.

Fig. 6-7b, p. 131

Estuaries and Coastal Wetlands: Centers of Productivity

Estuaries and Coastal Wetlands: Centers of Productivity

• Estuaries provide ecological and economic services.– Filter toxic pollutants, excess plant nutrients,

sediments, and other pollutants.– Reduce storm damage by absorbing waves and

storing excess water produced by storms and tsunamis.

– Provide food, habitats and nursery sites for many aquatic species.

Fig. 8-7

All consumersand producers to decomposersSecondary to

higher-level consumer

Primary to secondary consumer

Producer to primary consumer

Soft-shelledclam

BacteriaClamworm

Zooplankton andsmall crustaceans

Smelt

MarshPeriwinkle

Phytoplankton

Herring gulls

SnowyEgret

Peregrine falcon

Cordgrass

Short-billedDowitcher

Case Study:Dams, Wetlands, Hurricanes, and New Orleans

Case Study:Dams, Wetlands, Hurricanes, and New Orleans

• Dams and levees have been built to control water flows in New Orleans.

• Reduction in natural flow has destroyed natural wetlands.– Causes city to lie below sea-level (up to 3 meters).– Global sea levels have risen almost 0.3 meters since

1900.

Mangrove ForestsMangrove Forests

Figure 6-8Figure 6-8

What Kinds of Organisms Live in Aquatic Life Zones?What Kinds of Organisms Live in Aquatic Life Zones?• Aquatic systems contain floating, drifting,

swimming, bottom-dwelling, and decomposer organisms.– Plankton: important group of weakly swimming, free-

floating biota.• Phytoplankton (plant), Zooplankton (animal), Ultraplankton

(photosynthetic bacteria)

– Necton: fish, turtles, whales.– Benthos: bottom dwellers (barnacles, oysters).– Decomposers: breakdown organic compounds (mostly

bacteria).

Rocky and Sandy Shores: Living with the TidesRocky and Sandy Shores: Living with the Tides

• Organisms in intertidal zone develop specialized niches to deal with daily changes in:– Wave action

Figure 8-9Figure 8-9

Human Activities Are Disrupting and Degrading Marine SystemsHuman 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

Freshwater Life ZonesFreshwater Life Zones

Sunlight

Paintedturtle

Greenfrog

Pondsnail

Blue-wingedteal

Muskrat

Plankton

Northernpike

BloodwormsYellowperch

Divingbeetle

Littoral zone

Limnetic zone

Profundal zone

Benthic zone

Fig. 8-15

Types of Lakes: OligotrophicTypes of Lakes: Oligotrophic

Types of Lakes: EutrophicTypes of Lakes: Eutrophic

Effects of Plant Nutrients on Lakes:Too Much of a Good Thing

Effects of Plant Nutrients on Lakes:Too Much of a Good Thing

• Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support.

Figure 8-16Figure 8-16

River SystemsRiver SystemsRunoffRunoffWatershedWatershed

Drainage basinDrainage basinFloodplainFloodplain

Rain and snow

Source Zone

Water

Sediment

Lake Glacier RapidsWaterfall

TributaryFlood plain

Oxbow lake

Salt marsh

Delta Ocean

Depositedsediment

Transition Zone

Flood-Plain ZoneFig. 8-17

Source area

Rachel CarsonRachel Carson

• All at last returns to the sea-to Oceanus, the ocean river, like the ever-flowing stream of time, the beginning and the end.

• End chapter 8