L 4.5 Aquatic Ecosystems

Question 1

What factors affect life in aquatic ecosystems?

Answer 1

Aquatic organisms are affected primarily by the water’s depth, temperature, flow, and amount of dissolved nutrients.

Question 2

the photic zone

Answer 2

The sunlit region near the surface in which photosynthesis can occur

The photic zone may be as deep as 200 meters in tropical seas, but just a few meters deep or less in rivers and swamps.

Question 3

the Aphotic zone

Answer 3

Below the photic zone is the dark aphotic zone, where

photosynthesis cannot occur.

Question 4

benthos

Answer 4

aquatic organisms live on, or in, rocks and sediments on the bottoms of lakes, streams, and oceans.
their habitat is the benthic zone.

Question 5

What are the major categories of freshwater ecosystems?

Answer 5

Rivers and streams, lakes and ponds, and freshwater wetlands.

Question 6

where do Rivers, streams, creeks, and brooks often originate from?

Answer 6

underground water sources in mountains or hills.

Near a source, water has plenty of dissolved oxygen but little plant life.

Question 7

Plankton

Answer 7

is a general term that includes both phytoplankton

and zooplankton.

Question 8

wetland

Answer 8

an ecosystem in which water either covers the soil or is
present at or near the surface for at least part of the year.

Wetlands are often nutrient-rich, highly productive, and serve as breeding grounds for many organisms.

Question 9

Three main types of freshwater wetlands

Answer 9

freshwater bogs (wet, spongy ground with soil)

freshwater marshes (a tract of low wetland)

freshwater swamps (wetlands that are spongy often having certain types of trees and other vegetation.).

Question 10

Why are estuaries so important?

Answer 10

Estuaries serve as spawning (reproduction : production of fish eggs )
nursery grounds for many ecologically and commercially important fish and shellfish species including bluefish, striped bass, shrimp, and crabs.

Question 11

estuary

Answer 11

a special kind of wetland, formed where a river meets the
sea.

Estuaries contain a mixture of fresh water and salt water, and are affected by the rise and fall of ocean tides.

Many are shallow, which means that enough sunlight reaches the benthos to power photosynthesis.

Question 12

How do ecologists usually classify marine ecosystems?

Answer 12

Ecologists typically divide the ocean into zones based on depth and distance from shore.