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QUESTION 1 Identify the species most resilient to increasing atmospheric carbon dioxide concentrations. (A) corals (B) plankton (C) seagrasses (D) macroalgae QUESTIONS 1-2 These questions refer to the graph showing the projected vulnerabilities of groups of tropical marine species to increasing atmospheric carbon dioxide concentrations. Recorded concentrations of atmospheric CO at specific times are also shown. Corals Fish Plankton Mangroves Seagrasses Macroalgae | 380 400 450 500 550 Atmospheric carbon dioxide concentration (parts per million) Key Projected vulnerability ——— —Stiéid Low Moderate High Very high
QUESTION 3 Which factor has the greatest influence on biodiversity of coral reef fish species? (A) rugosity (B) predation (C) light availability (D) dissolved oxygen
QUESTION 6 The abiotic factor limiting the carrying capacity of an Atlantic salmon farm is low (A) dissolved oxygen. (B) temperature. (C) ammonia. (D) nitrites.
QUESTION 7 The anatomy of a coral is shown. BOOCOOE qa X indicates a (A) zooxanthella. (B) nematocyst. (C) coelenteron. (D) tentacle. QUESTIONS 8-9 These questions refer to the graph showing the occurrence of coral species across four locations (I I III and IV). fs Number of ree —v MN a) WX GG QQ... .GAAAAA _ Key a a Y--py A) ee ie Hb cel le 2 St Mn As Mo Coral species a ee ee eee es rr I LI to i 1
QUESTION 8 Identify the species seen on the greatest number of reefs in location III. (A) Po (B) Ac (C) St (D) Mn
QUESTION 9 Species evenness is lowest at location (A) I. (B) IL. (C) Ul. (D) IV. QUESTIONS 10-11 These questions refer to the graph showing the concentration of polychlorinated biphenyl (PCB) in the lipids of various organisms from the north-eastern Pacific Ocean. Error bars show standard deviation. 4.0 =S 3.0 = ivy 2.0 Transient = Southern resident killer whale ° killer whale & 10 s $ Steller sea lion = cD) e on Pollock 5 o —1.0 Zoovlankt Fonageg # chum salmon oplankton 2 204 7? So ° = 0.0 1.0 2.0 3.0 4.0 5.0 6.0 Trophic level
QUESTION 10 What is the relationship between mean PCB concentration and trophic level? (A) (B) (C) (D) Mean PCB concentration causes a change in trophic level. As trophic level increases mean PCB concentration increases. There is no relationship between trophic level and mean PCB concentration. There is a negative correlation between trophic level and mean PCB concentration.
QUESTION 11 The mean PCB concentration of zooplankton and southern resident killer whales differ by an approximate factor of (A) 3 (B) 30 (C) 100 (D) 1000
QUESTION 12 When the recovery pathway of an ecosystem differs from its degradation pathway the ecosystem (A) shows hysteresis. (B) has low resilience. (C) has high biodiversity. (D) exists in a single stable state.
QUESTION 13 Which type of fishery is most likely to be a food source for small communities from developing nations? (A) trawling (B) artisanal (C) commercial (D) recreational
QUESTION 14 Identify the relationship between atmospheric CO concentration ocean pH and temperature. (A) Increased atmospheric temperature has led to increased atmospheric CO concentration ocean temperature and pH. (B) Decreased ocean pH has led to increased atmospheric temperature and decreased atmospheric CO concentration. (C) Increased atmospheric CO concentration has led to decreased ocean pH and increased ocean temperature. (D) Decreased ocean temperature has led to increased atmospheric CO concentration and ocean pH.
QUESTION 16 A reef cross-section is shown. The structure labelled X is (A) a fringing reef. (B) a barrier reef. (C) aplatform. (D) an atoll.
QUESTION 17 Coral reef growth occurs when the (A) dissolution rate is the same as the calcification rate. (B) calcification rate is less than the destruction processes. (C) accretion rate is greater than the dissolution and erosion rates. (D) dissolution and erosion rates are greater than the accretion rate.
QUESTION 19 An effect of climate change on coral reef health is (A) (B) (C) (D) decreased surface run-off. increased COTS outbreaks. increased coral bleaching events. decreased cyclone frequency and severity.
QUESTION 25 (§ marks) Representative concentration pathways (RCPs) are greenhouse gas concentration trajectories that describe different climate futures depending on the volume of greenhouse gases emitted in future years. The graphs show long-term changes in ocean pH and hydrogen ion concentration [H’] using historical observations and modelled predictions using RCP scenarios between 1770 and 2100. a) Which RCP scenario predicts that ocean pH will stabilise? [1 mark] b) Explain the relationship between [H ] and ocean pH using evidence from the graphs. [2 marks] c) Describe two consequences for coral reef ecosystems under the RCP 8.5 scenario. [2 marks]
Difficulty: A
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Paper 1
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2023
QUESTION 15 Most hard corals only extend their tentacles at night as this is when (A) spawning occurs. (B) zooxanthellae photosynthesise. (C) zooplankton are more abundant. (D) corallivorous fish are more active.
QUESTION 7 (11 marks) The graph shows Australian prawn production by sector from 2006-07 to 2026-27. a) Identify the financial year in the historical data when wild caught prawn production had the highest economic value. [1 mark] b) Describe the trend in total economic value for Australian prawns from 2016-17 to 2021-22. Suggest two possible reasons for this trend. [3 marks] c) Compare the historical and predicted economic value of Australian prawns. [3 marks] Similarity: Difference: Significance: d) Explain two attributes that make prawns a desirable species to farm. [4 marks]
Difficulty: A
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Paper 2
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2023
QUESTION 1 (4 marks) a) Explain the relationship between dissolved oxygen concentration and the distribution of coral reefs. [2 marks] b) Identify two other abiotic factors that affect the distribution of coral reefs. [2 marks]
QUESTION 4 (5 marks) a) In which life cycle stage of a typical reef-forming hard coral does site selection occur? [1 mark] b) Explain how one biotic and one abiotic factor affect the site selection process. [4 marks]
QUESTION 5 (3 marks) Explain the role of connectivity in species replenishment using a relevant fish species as an example.
QUESTION 6 (4 marks) The graph shows global trends in marine fish stocks from 1974-2017. 100 % Nn So SP TT PM SL 1 Key Overfished [| Fully fished || Underfished a) Identify the percentage of stocks that were fully fished in 2017. [1 mark] b) Draw a conclusion about the status of global fisheries. Justify your conclusion. [3 marks]
QUESTION 2 (5 marks) A coastal community plans to implement a shark control program to significantly reduce the tiger shark population because of their perceived threat to the fishing industry and swimmers. The diagram represents potential effects of ongoing changes in predation for a seagrass ecosystem. a) Explain the effect of removing tiger sharks on seagrass ecosystems. [3 marks] b) Predict the effect that the shark control program would have on the fishing industry in this coastal community. [2 marks]
QUESTION 3 (11 marks) a) Identify the system that enables ocean water to resist pH change when exposed to increased atmospheric carbon dioxide (CO ). [1 mark] b) Identify one natural and two anthropogenic causes of increased atmospheric CO . [3 marks] Natural: Anthropogenic: c) Describe how increased atmospheric CO affects levels of hydrogen and carbonate ions in ocean waters. [4 marks] d) Explain what implications a change in levels of carbonate ions from increased atmospheric CO has for shell-forming organisms. [3 marks]
QUESTION 26 (3 marks) The stock of a wild migratory Australian fish species needs sustainable management before being used as a commercial resource. However there is little scientific data about the species’ behaviours and distribution. a) Explain how the precautionary principle applies to this situation. [1 mark] b) Explain one management technique that should be implemented to prevent overexploitation of this resource. [2 marks]
QUESTION 23 (5 marks) The table shows the marine organisms sighted during a survey of three reefs in the Great Barrier Reef Marine Park. [seeciembe | 6 | 4 | 3 _ [cimccm [| 4 |e [3 raneevetss [| 0 [0 | 0 [comer | tf oe | o [convo f 2 | ° | 7 Dewees | 0 fo | a a [sw fo _[ oe _| 1 _ sor om fos | a) Use Simpson’s diversity index (SDI) to calculate the biodiversity of reef C. Show your working. [2 marks] xn(n-1 SDI=1-— eS) b) Compare the diversity of the three reefs. [3 marks] Similarity: Difference: Significance:
QUESTION 8 (5 marks) A long-term program monitors changes in hard coral cover along the Great Barrier Reef (GBR) for three locations. Average coral cover (and 95% confidence intervals) from 1986--2021 are shown. a) Identify which region had the highest proportion of reefs with very high coral cover. Show your reasoning. [2 marks] b) Identify a similarity and a difference in the trend in coral cover from 2012-2021 for the northern and southern regions. [2 marks] Similarity: Difference: c) Identify a limitation of the data. [1 mark]
QUESTION 30 (2 marks) Seasonal freshwater flows from a river may cause regional changes in coral reef species. Describe how a specific pressure will affect coral species diversity from inshore to offshore.
QUESTION 7 (2 marks) A mass coral bleaching event in 1998 caused a decline in average coral cover for a reef. Identify an implication for the fish populations associated with this reef. Give a reason for your response.
QUESTION 14 (2 marks) Describe two factors that affect the probability that a reef will recover from a bleaching event. l. 2.
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