Essentials of Ecology

CONCEPT 8-2 167

Figure 8-6 View of an estuary from space. The

photo shows the sediment plume (turbidity caused

by runoff) at the mouth of Madagascar’s Betsiboka

River as it flows through the estuary and into the

Mozambique Channel. Because of its topography,

heavy rainfall, and the clearing of forests for ag-

riculture, Madagascar is the world’s most eroded

country.

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.

Bacteria

Clamworm

Zooplankton and

small crustaceans

Smelt

Marsh

periwinkle

Short-billed

dowitcher

Cordgrass

Peregrine falcon

Snowy

egret

Herring gulls

Phytoplankton

Soft-shelled

clam

Bacteria

Clamworm

Zooplankton and

small crustaceans

Smelt

Marsh

periwinkle

Short-billed

dowitcher

Cordgrass

Peregrine falcon

Snowy

egret

Herring gulls

Phytoplankton

Soft-shelled

clam

Producer to

primary

consumer

Primary to

secondary

consumer

Secondary to

higher-level

consumer

All consumers

and producers

to decomposers

SuperStock

NASA