Essentials of Ecology

CONCEPT 8-3 171

Figure 8-11 Natural capital:

some components and interac-

tions 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 con-

sumers (carnivores), and decom-

posers. Organisms are not drawn

to scale.

Producer

to primary

consumer

Primary

to secondary

consumer

Secondary to

higher-level

consumer

All producers and

consumers to

decomposers

Gray reef shark

Parrot fish

Hard corals

Symbiotic

algae

Phytoplankton

Algae

Sponges

Zooplankton

Bacteria

Moray

eel

Coney

Blackcap basslet

Banded coral

shrimp

Brittle star

Sergeant major

Blue Fairy basslet

tang

Sea nettle

Green sea

turtle

Gray reef shark

Parrot fish

Hard corals

Symbiotic

algae

Phytoplankton

Algae

Sponges

Zooplankton

Bacteria

Moray

eel

Coney

Blackcap basslet

Banded coral

shrimp

Brittle star

Sergeant major

Blue Fairy basslet

tang

Sea nettle

Green sea

turtle

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

Human activities are disrupting and degrading some eco-

logical and economic services provided by marine aquatic

systems, especially coastal wetlands, shorelines, man-

grove forests, and coral reefs (Concept 8-3). (See The Hab-

itable Planet, Video 9, at http://www.learner.org/resources/

series209.html.) Thus, a single largely land-based

species—humans—is increasingly threatening the bio-

logical diversity and ecosystem services provided by the

oceans that cover about 71% of the earth’s surface.

In 2008, the U.S. National Center for Ecological

Analysis and Synthesis (NCEAS) used computer models