Widespread anthropogenic nitrogen in the northwestern Pacific Ocean sediment

• Published in: Environmental Science & Technology
• Main Authors: Haryun Kim, LEE, KITACK, Dhong-Il Lim, Seung-Il Nam, Tae-Wook Kim, Jin-Yu T. Yang, Young Ho Ko, Kyung-Hoon Shin, Eunil Lee
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER CHEMICAL SOC 2017
• Subjects: SOUTH CHINA SEA; ORGANIC-MATTER SOURCES; SURFACE SEDIMENTS; ARCTIC-OCEAN; YELLOW SEA; ISOTOPIC COMPOSITION; RIVER ESTUARY; CARBON; SHELF; DEPOSITION; Arctic; Arctic Ocean; Chukchi Sea; Pacific; Chukchi
• Online Access: https://oasis.postech.ac.kr/handle/2014.oak/39116; https://doi.org/10.1021/acs.est.6b05316

Sediment samples from the East China and Yellow seas collected adjacent to continental China were found to have lower delta N-15 values (expressed as delta N-15 = [N-15:N-14(sample)/N-15:N-14(air) - 1] x 1000; the sediment N-15:N-14 ratio relative to the air nitrogen 15N:14N ratio). In contrast, the Arctic sediments from the Chukchi Sea, the sampling region furthest from China, showed higher delta N-15 values (2-3 higher than those representing the East China and the Yellow sea sediments). Across the sites sampled, the levels of sediment delta N-15 increased with increasing distance from China, which is broadly consistent with the decreasing influence of anthropogenic nitrogen (N-ANTH) resulting from fossil fuel combustion and fertilizer use. We concluded that, of several processes, the input of N-ANTH appears to be emerging as a new driver of change in the sediment delta N-15 value in marginal seas adjacent to China. The present results indicate that the effect of N-ANTH has extended beyond the ocean water column into the deep sedimentary environment, presumably via biological assimilation of N-ANTH followed by deposition. Further, the findings indicate that N-ANTH is taking over from the conventional paradigm of nitrate flux from nitrate-rich deep water as the primary driver of biological export production in this region of the Pacific Ocean. 1 1 2 N scie scopus