#### 900A micropaleontologist collected 120 samples of foraminifera from a sediment core. She analyzed 25% of the samples using oxygen isotope ratios to reconstruct past temperatures, and 40% using carbon isotope ratios for paleoproductivity. If 10% were analyzed using both methods, how many samples were analyzed using only one method?

Tue, 21 Apr 2026 06:49:28 +0000

#### 900A Micropaleontologist Collected 120 Samples of Foraminifera from a Sediment Core—Here’s What the Data Reveals In the growing conversation about climate history and Earth’s environmental shifts, interest in microfossil analysis has surged, fueled by rising awareness of paleoclimate science’s role in understanding global change. A recent study by 900A micropaleontologist collected 120 samples from a sediment core to explore this frontier. By examining foraminifera—tiny marine organisms preserved in sediment—she aimed to reconstruct ancient climate conditions, offering insights into long-term temperature and ocean productivity patterns. This work sits at the intersection of geology, environmental science, and data-driven storytelling, inviting readers to engage with cutting-edge Earth research. Understanding how sample analysis shapes climate reconstruction reveals a precise scientific process. The researcher analyzed 25% of the 120 samples—30 specimens—using oxygen isotope ratios to infer past temperature variations. Additional analysis included 40%—48 samples—via carbon isotope ratios, which illuminate historical biological productivity and carbon cycling. Notably, 10% overlapped in analysis, assessed as samples analyzed with both methods. This overlap helps confirm data reliability across multiple proxies, strengthening the broader narrative of environmental shifts over time. Counting only samples analyzed with one method reveals a key breakdown: 30 samples with oxygen isotopes, 48 with carbon isotopes, and 12 shared (10% of 120). The exclusive oxygen-only group totals 18 samples, while carbon-only accounts for 36. Combined, 54 samples were analyzed through a single, focused method—offering a clean view of targeted scientific inquiry. This clarity underscores the precision required in paleoclimate reconstruction, where each analytical choice builds trust in the results.