2026-02-05 中国科学院（CAS）
Schematic diagram of the potential impact mechanism of seamount on OMZ expansion. (Image by IOCAS)
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/earth/202602/t20260205_1149808.shtml
- https://www.sciencedirect.com/science/article/abs/pii/S007966112500254X
西太平洋の弱酸素極小層（OMZ）に対する海山の潜在的影響 Potential impact of seamount on the mild oxygen minimum zone (OMZ) in the Western Pacific
Jun Ma, Lilian Wen, Xuegang Li, Kuidong Xu, Jiajia Dai, Yi Sun, Guorong Zhong, Detong Tian, Huamao Yuan, Liqin Duan, Jinming Song
Progress in Oceanography Available online: 6 January 2026
DOI:https://doi.org/10.1016/j.pocean.2025.103666
Highlights
- The “seamount effect” is stronger in cruise 1 in the M4 seamount.
- Seamount may increase the range and intensity of OMZ from two aspects.
- Speculation (1): Upwellings may uplift isoline of low DO.
- Speculation (2): Biological activities in sediments may consume DO.
Abstract
Seamount and the oxygen minimum zone (OMZ) are often two typical habitats coexisting in the deep sea, and studying the relationship between the “seamount effect” and OMZ is of great significance to improve the cognitive level of the two typical deep-sea habitats. Based on the investigation of the two cruises in the M4 seamount of the Western Pacific, this study revealed the “seamount effect”, explored the impact of seamount and environmental parameters on OMZ. The results showed that the uplifts of the isohaline, isotherm and isopycnal occurred near the summit in the two cruises, and the isolines of NO3-N, PO4-P and NO2-N were also elevated near the summit. Meanwhile, the ratio of the average concentration of POC near the summit for cruise 1 to cruise 2 can reach up to about 2 times. This may indicate that there was a “seamount effect” in both cruises, and it was stronger in cruise 1. The range and intensity of OMZ in both cruises were similar, with the range of 550–1100 m and (330–380, 850–1100) m, respectively. The impact of seamount on OMZ may be reflected in two aspects. One possible mechanism was that the hydrological phenomena such as upwelling near the summit may raise the isolines of low concentration DO in 200–300 m, increasing the range of the upper boundary of OMZ; Another possibility was that the biological activities of seamount sediments continuously may consume DO, such as in 1000 m at station A7 of cruise 1, increasing the intensity of OMZ. In addition, the temperature below 1000 m directly controlled the upper boundary of OMZ, while the decomposition of organic matter in 75–300 m above the OMZ consumed DO, which also had an important impact on the range and intensity of the OMZ.
