Question

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:

Step1: Analyze Option A

The graph shows that when there is a local decline in L. pertusa (e.g., around 9000 years ago in the Alboran Sea), there is a substantial increase in oxygenation in the Alboran Sea. This shows a clear opposite relationship.

Step2: Analyze Option B

The graph does not support that L. pertusa declined in the Alboran Sea during a period of substantial local decline in oxygenation. In fact, the opposite is seen in some cases.

Step3: Analyze Option C

The graph does not indicate that oxygenation in the Alboran Sea was higher before the decline in L. pertusa than after. There is no such clear - cut comparison shown in the graph.

Step4: Analyze Option D

The graph does not show that oxygenation in the Alboran Sea tended to be substantially higher than oxygenation near the Mauritanian coast during the period studied. The data is about the relationship between L. pertusa and local oxygenation in different regions, not a direct comparison of oxygenation levels between the two coasts.

Answer:

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