Q2 - Ocean Acidification and Deep-Sea Chemosynthesis

Theoretical B Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Ecology Bioenergetics & Central Metabolism Overview

Oceans also sink more than 30% of anthropogenic carbon dioxide, which dissolves to form an acid that alters calcium carbonate solubility (1). Many marine invertebrates have calcium carbonate skeletons, which form marine sediments and reefs. The British island of Bermuda is a hub for studying coral reefs and sea trenches, so the effect of CO on Bermudan sediments in seawater was measured (2). Five thousand metres below the reefs, 2 marine bacteria fix CO to grow (3). 2

Figure 1 for Q2: Ocean Acidification and Deep-Sea Chemosynthesis

Using the information and data, determine which of the statements are true or which are false.

A. Anthropogenic carbon dioxide damages invertebrate skeletons.

B. The structure of the Bermudan barrier reef is under threat due to changes in seawater chemistry.

C. The growth of invertebrates contributes to the oceans' ability to sink carbon.

D. Bacteria at hydrothermal vents use modified photosynthetic enzymes to fix carbon.

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Question reproduced from IBO 2017, Theoretical Exam B, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Official answer key & worked solutions