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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
General Certificate of Education
Advanced Subsidiary Level and Advanced Level
*7998116654*
9693/02
MARINE SCIENCE
Paper 2 AS Data Handling and Free Response
May/June 2008
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use a pencil for any diagrams, graphs or rough work.
Do not use staples, paper clips, highlighters, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
For Examiner’s Use
1
2
3
4
Total
This document consists of 9 printed pages, 6 lined pages and 1 blank page.
SPA (SJF4703/CG) T50279/3
© UCLES 2008
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2
Section A
1
In October 1998, Hurricane Mitch caused much damage to the mangrove swamps on the Pacific
coast of the Honduras. This area contains many shrimp farms, and these were also damaged.
People involved in shrimp aquaculture were keen to help restore the mangroves, as this could
benefit their industry.
The restoration programme began with an investigation into the factors affecting mangrove
distribution in the area.
(a) The distribution and height of mangrove trees was investigated at two sites, Oxidacion and
Pedregal.
•
•
Oxidacion is on the shoreline of a small river where the waste from shrimp farms flows
into the water.
Pedregal is an estuary on the same river system as Oxidacion.
At each site, counts and measurements were made at 10 m intervals at varying distances
from the open water, beginning inland and working towards the open water. At Oxidacion,
measurements of salinity were also made at five sites.
The results are shown in Fig. 1.1.
20
Oxidacion
18
height / m
70
16
60
14
12
50
10
40
8
30
6
10
2
0
0
10 20 30 40 50 60 70 80 90 100
distance / m
inland
open water
20
Key
16
salinity
14
Avicennia germinans
black mangrove trees
12
10
Rhizophora mangle
red mangrove trees
8
6
4
2
0
10 20 30 40 50 60 70 80 90 100
distance / m
inland
open water
Fig. 1.1
© UCLES 2008
0
Pedregal
18
0
salinity / parts
per thousand
20
4
height / m
80
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(i)
Compare the distribution of black mangrove trees and red mangrove trees at
Oxidacion.
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(ii)
Compare the results for black mangrove trees at Oxidacion and at Pedregal.
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(b) The researchers analysed the data shown in Fig. 1.1 and then put forward the following
hypothesis:
Black mangrove trees can tolerate higher salinity than red mangrove trees.
(i)
Do you consider that the results support this hypothesis? Explain your answer.
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(ii)
Outline a laboratory-based experiment that the researchers could do to test their
hypothesis.
Your answer should include reference to the control of variables, and the collection
of quantitative results.
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(c) The researchers also measured the ratio of carbon to nitrogen, C:N, in the mud in which
the mangrove trees were growing.
At both Oxidacion and Pedregal, measurements were taken at three points in the
mangrove swamp:
•
•
•
at the inland edge of the swamp
in the middle of the swamp
at the outer edge of the swamp, next to the open water.
Their results are shown in Fig. 1.2. A high C:N ratio indicates poor availability of
nutrients.
12
C:N ratio
10
Pedregal
8
6
Oxidacion
4
2
0
inland edge
of swamp
middle
of swamp
outer edge of swamp
next to open water
Fig. 1.2
Suggest a reason for:
(i)
the changes in C:N ratio from the inland edge to the outer edge of the mangrove
swamp,
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(ii)
the differences between the C:N ratio at Pedregal compared with Oxidacion.
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(d) Suggest why the restoration and regrowth of the mangrove swamps could help the
shrimp farming industry.
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[Total: 12]
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2
Fig. 2.1 shows the differences in surface water temperatures in the southern Pacific Ocean in a
‘normal’ year and in an El Niño year.
normal year
America
40 N
20 N
cold water
South
America
20 S
strong trade winds
Australia
150 E
180
150 W
0 Equator
strong Peru current
120 W
90 W
60 W
40 S
El Nino year
America
40 N
20 N
warm water
‘reversed’ winds
Australia
150 E
180
150 W
20 S
weak Peru current
120 W
90 W
Fig. 2.1
© UCLES 2008
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South
America
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60 W
40 S
7
Fig. 2.2 shows the temperature of the water between 0 and 200 m depth, at the equator at a
latitude of 110 °W, between July 1981 and June 1983.
0
depth / m
50
100
150
200
J A S O N D J
1981
F M A M J
Key
J A S O N D J
1982
F M A M J
1983
temperature / °C
<15
15–20
20–25
25–30
>30
Fig. 2.2
(a) With reference to Fig. 2.1 and Fig. 2.2, state which year or years were El Niño years.
Explain your answer.
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(b) The change in surface temperatures in an El Niño year is thought to be a result of the
change in direction of the trade winds.
Explain how this can cause the differences in surface temperatures between a normal
year and an El Niño year shown in Fig. 2.1.
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(c) During an El Niño year, there is often severe drought in eastern Australia.
For
Examiner’s
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With reference to Fig. 2.1, explain how this may be brought about.
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(d) The western coast of South America usually provides a rich harvest of anchovies and
other fish, but this does not happen in an El Niño year.
With reference to Fig. 2.1 and Fig. 2.2, explain the reasons for this drop in fish catches.
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[Total: 8]
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Section B
Answer both questions in this section.
3
(a) Explain the meaning of the term ecosystem.
[2]
(b) Describe the relationship between corals and zooxanthellae.
[7]
(c) Discuss the possible reasons for the very high biodiversity on coral reefs.
[6]
[Total: 15]
4
(a) Explain how hydrothermal vents are produced.
[7]
(b) Describe the unusual food web that exists at deep sea hydrothermal vents.
[8]
[Total: 15]
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BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable
effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will
be pleased to make amends at the earliest possible opportunity.
University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of
Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
9693/02/M/J/08