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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
General Certificate of Education
Advanced Subsidiary Level and Advanced Level
* 6 1 2 4 7 4 2 0 6 7 *
9693/02
MARINE SCIENCE
Paper 2 AS Data Handling and Free Response
October/November 2012
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
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4
Total
This document consists of 9 printed pages and 3 blank pages.
DC (RW/SW) 50645/1
© UCLES 2012
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Section A
For
Examiner’s
Use
Answer both questions.
1
In an investigation, the concentration of dissolved carbon dioxide and the pH of the water in
a lagoon were measured at regular intervals over a period of 24 hours.
The results are shown in Table 1.1.
Table 1.1
time
(24 hour clock)
concentration of
carbon dioxide
/ mg dm–3
pH of water
0600
26.7
6.5
1200
8.2
6.9
1800
2.8
7.5
2400
10.2
6.8
0600
27.1
6.4
(a) Using the information in Table 1.1, describe the changes in the concentration of carbon
dioxide.
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(b) Suggest explanations for the changes you have described.
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Examiner’s
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(c) (i)
Describe the relationship between the concentration of dissolved carbon dioxide
and the pH of the water.
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(ii)
Suggest an explanation for this relationship.
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[Total: 10]
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2
The calcification rate of a coral is a measure of the rate at which calcium carbonate (CaCO3)
is deposited in a coral skeleton. The calcification rate is influenced by a number of factors,
including the availability of calcium carbonate and the temperature of sea water.
(a) Suggest two factors, other than temperature and availability of calcium carbonate, that
affect the growth rate of corals. Give an explanation for the effect of each factor on the
growth rate of corals.
factor 1 .............................................................................................................................
effect on growth rate of coral ...........................................................................................
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factor 2 .............................................................................................................................
effect on growth rate of coral ...........................................................................................
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(b) In an investigation, the calcification rates of a large coral (Porites) were determined at a
number of sites in Australia, Hawaii and Thailand. The calcification rate was measured
as the mass of calcium carbonate deposited in the coral, per unit area, per year.
The results of this investigation are shown in Fig. 2.1.
3.0
2.5
2.0
coral calcification rate
/ g CaCO3 cm–2 yr–1
1.5
1.0
0.5
0.0
23
24
25
26
27
sea surface temperature / °C
Fig. 2.1
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For
Examiner’s
Use
5
(i)
Formulate a suitable hypothesis, based on the data shown in Fig. 2.1, for this
investigation.
For
Examiner’s
Use
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(ii)
Do the results of this investigation support or refute your hypothesis? Give an
explanation for your answer.
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(iii)
Give reasons why the data shown in Fig. 2.1 could lead to uncertainty in the
interpretation of the results.
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[Total: 10]
© UCLES 2012
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Section B
Answer both questions.
3
(a) Explain what is meant by the Coriolis effect.
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(b) Explain how salinity gradients form in water columns to produce ocean layers and how
subsequent mixing of these layers may occur.
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Examiner’s
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7
(c) Suggest explanations for each of these observations.
(i)
For
Examiner’s
Use
The concentration of dissolved oxygen is often low in a lagoon.
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(ii)
The salinity of the water in a lagoon may be higher than the salinity in the open
ocean.
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4
(a) Explain how isostasy may produce shallow seas at the edge of continents.
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(b) Explain how the processes of erosion and sedimentation give rise to the formation of
rocky shores and muddy shores.
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9
(c) State what is meant by the term biodiversity and explain why rocky shores usually have
a higher biodiversity than sandy shores.
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[Total: 15]
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Examiner’s
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BLANK PAGE
© UCLES 2012
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Copyright Acknowledgements:
Question 1
Question 2
Table 1.1
Figure 2.1
© ADAPTED: Keeley et al; American Journal of Botany; http://www.werc.usgs.gov/OLDsitedata/seki/pdfs/ajb4.pdf.
© ADAPTED: http://people.uncw.edu/szmanta/2006%20pdfs/20%20Global%20warming%20issues/McNeil%20etal%2004%20
GRL%20calcification%20with%20warming%20with%20comments%20and%20reply.pdf.
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.
© UCLES 2012
9693/02/O/N/12