Excerpt from EDC Earth Science
Chapter 3 | The Peru Current
Teacher Guide
to Activities
Purpose
Students apply their understanding of ocean currents and develop their
knowledge about the connection of the Peru Current to the biosphere.
They will learn about the relationships between air temperature, seasurface
tempera­ture, rainfall, and chlorophyll concentrations.
Students learn about systems and system models, cause and effect,
and ­patterns. They are asked to analyze and interpret data and construct
­explanations (NGSS: ESS2.C.2, ESS2.D.1, ESS2.D.2).
Contents
Data Learning Objective
•Student Activity 2
• The student will read and make meaning from a variety of data visualizations and relate the data to real events and physical processes .
•Teacher Guide Section 4
• The student will relate multiple data parameters to each other and to real
events and physical processes.
Description
Students read about the Peru Current and learn about upwelling. Students
use the two visualizations of sea surface temperature and chlorophyll concentrations in this activity to identify and describe evidence of upwelling along
the Peru coastline in order to better understand the phenomenon.
© 2015 Education Development Center, Inc. 1
Excerpt from EDC Earth Science | Chapter 3 | The Peru Current
Student Activity
READING
The Peru Current
The Peru Current, shown in Figure 3.13, is an eastern
boundary current and is relatively wide and slow. It
carries cold, low-­salinity water from Antarctic waters
toward the equator.
As the Peru Current flows along the coast of Chile,
Peru, and southern Ecuador, it cools the air and thus
the climate of these coastal areas. Cool air doesn’t hold
much water, so there is very little precipitation along
the coast. Because of the cool air and the position of
the Andes Mountains to the east, which also prevent
moisture from reaching the coast, the strip of land
along the coast between the ocean and the mountains
is one of the driest deserts in the world. In fact, there
is evidence that the Atacama Desert in northern Chile,
shown in Figure 3.14, had no significant rainfall from
1570 to 1971.
Peru
Peru
Current
FIGURE 3.13
The Peru Current flows from south
to north
the west coast of
3861 EDPS Earth Science Student Book,
Part along
1
Figure: 3861 EDPS EaSci SB03_13 South America.
Cronos Pro Regular 8/9
FIGURE 3.14
The Atacama Desert along the
coast of northern Chile receives
­virtually no rainfall.
However, an amazing contrast exists along this parched coast. This barren
desert borders one of the most productive marine ecosystems in the world,
supporting an incredible abundance of marine life.
How is this possible?
2 © 2015 Education Development Center, Inc.
Excerpt from EDC Earth Science | Chapter 3 | The Peru Current
Think About It The two images in Figure 3.15
show the sea-surface temperature and chlorophyll
concentrations off the coast of Peru. When chlorophyll is detected in the seawater, it indicates that
photosynthesizing plants, such as phytoplankton,
are present. What evidence of upwelling do you see
in these images?
5N
28
Columbia
Ecuador
26
25
5S
Peru
Brazil
24
23
10S
22
15S
21
Bolivia
20
20S
Sea surface temperature (degrees Celsius)
27
Eq
19
18
Chile
25S
87W
81W
75W
69W
30.0
3861 EDPS Earth Science Student Book, Part 1
Figure:
5° N 3861 EDPS EaSci SB03_15a
Cronos Pro Regular 8/9
Columbia
27.545
24.108
Eq
Ecuador
20.671
5° S
Peru
Brazil
10° S
17.234
13.798
10.361
15° S
Bolivia
6.924
20° S
Chile
25° S
Chlorophyll concentration (mg/m3)
However, an amazing contrast exists along this
parched coast. This barren desert borders one of the
most productive marine ecosystems in the world,
supporting an incredible abundance of marine life.
How is this possible?
As it turns out, under normal conditions, the
prevailing winds along the coast of Peru push the
water away from the land, causing a phenomenon called upwelling (the upward movement of
ocean water). As water is moved away from the
coast, cold, nutrient-rich water rises from below
to replace it. These nutrients, when brought to the
surface by upwelling, act as plant fertilizers and
promote the growth of photosynthesizing organisms such as phytoplankton (photosynthesizing
microscopic organisms that float in sea water),
which in turn provide a food source for millions
of fish. The abundance of fish in the Peru Current
supplied Thor Heyerdahl and his companions with
a rich diet as they drifted on their raft. In fact, this
current is so full of life that it feeds much of the
world. Approximately 18%–20% of the world’s fish
catch comes from the Peru Current Large Marine
Ecosystem (LME). As such, if you’re a fish eater,
there’s a good chance this current has provided a
meal for you.
Student Activity
3.487
0.05
87° W
81° W
75° W
69° W
FIGURE 3.15
3861 EDPS Earth Science Student Book, Part 1
Sea-surface temperatures (top) and chlorophyll
Figure: 3861 EDPS EaSci SB03_15b
(bottom) off the coast of Peru during
Cronos­concentrations
Pro Regular 8/9
December of 2004. (These measurements were taken
by instruments on satellites. The white areas in the
chlorophyll map are areas where no data could be
­collected because of clouds.) 7
© 2015 Education Development Center, Inc. 3
Excerpt from EDC Earth Science | Chapter 3 | The Peru Current
READING
The Peru Current
This reading describes the Peru
Current and how changes in the
strength and direction of currents,
such as during ENSO events, can
have far-reaching effects on marine
ecosystems and the climate of
land areas.
Response to Think About It
Think About It The two images in
Figure 3.15 show the sea-surface
temperature and chlorophyll
concentrations off the coast of Peru.
When chlorophyll is detected in the
seawater, it indicates that photosynthesizing plants, such as phytoplankton, are present. What
evidence of upwelling do you see in
these images? The water just off the
coast of Peru is relatively low in
temperature, which is evidence that
deeper, cooler water is rising to the
surface in this area. The higher levels
of chlorophyll in the water along the
coast reflects the fact that nutrient-rich water from the ocean
bottom is rising to the surface,
spurring the growth of photosynthetic organisms.
4 © 2015 Education Development Center, Inc.
Teacher Guide Section