Question

1. the population of the coral lophelia pertusa declined significantly around 9,000 years ago in the alboran sea and around 11,000 years ago near the mauritanian coast. using the ratio of manganese to calcium, which inversely correlates with ocean oxygenation levels, marine scientist rodrigo da costa portilho-ramos and colleagues evaluated whether oxygenation played a role in the declines of l. pertusa. the researchers concluded that oxygenation may have been important in the alboran sea but not near the mauritanian coast, since ______

which choice most effectively uses data from the graph to complete the statement?
a) a substantial increase in oxygenation in the alboran sea corresponded with the local decline in l. pertusa, but the opposite relationship between oxygenation and l. pertusa was found near the mauritanian coast.
b) l. pertusa declined in the alboran sea during a period of substantial local decline in oxygenation, but l. pertusa declined near the mauritanian coast during a period of little local change in oxygenation.
c) oxygenation in the alboran sea was higher before the decline in l. pertusa than after the decline, whereas oxygenation near the mauritanian coast was relatively low both before and after the decline in l. pertusa.
d) oxygenation in the alboran sea tended to be substantially higher than oxygenation near the mauritanian coast during the period studied.

Explanation:

To solve this, we analyze each option based on the context: the researchers concluded oxygenation was important in Alboran Sea but not Mauritanian coast. The key is the relationship between oxygenation change and coral decline.

• Option A: Says opposite relationships, but the conclusion is oxygenation was important in Alboran (so a corresponding change) and not in Mauritanian (so no corresponding change). Opposite relationship in Mauritanian would imply oxygenation was important there, which contradicts the conclusion. Eliminate A.
• Option B: In Alboran, coral declined during a substantial local decline in oxygenation (so oxygenation change correlates with decline, meaning oxygenation was important). In Mauritanian, coral declined during little local change in oxygenation (so oxygenation didn't change, so it wasn't important in that decline). This matches the researchers' conclusion.
• Option C: Compares oxygenation before and after decline, but the conclusion is about the role of oxygenation in the decline (during the decline period), not before/after. Irrelevant. Eliminate C.
• Option D: Compares oxygenation levels between the two seas, but the conclusion is about the role of oxygenation in each sea's coral decline, not the comparison of levels between seas. Eliminate D.

Answer:

B) L. pertusa declined in the Alboran Sea during a period of substantial local decline in oxygenation, but L. pertusa declined near the Mauritanian coast during a period of little local change in oxygenation.