Jang-Mu Heo1, Seong-Su Kim1, Sung-Ho Kang2, Eun Jin Yang2, Ki-Tae Park2, Jinyoung Jung2, Kyoung-Ho Cho2, Ju-Hyoung Kim3, Alison M Macdonald4, Joo-Eun Yoon1, Hyo-Ryeon Kim1, Sang-Min Eom1, Jae-Hyun Lim5, Il-Nam Kim6. 1. Department of Marine Science, Incheon National University, Incheon, 22012, South Korea. 2. Korea Polar Research Institute, Incheon, 21990, South Korea. 3. Faculty of Marine Applied Biosciences, Kunsan National University, Gunsan, 54150, South Korea. 4. Physical Oceanography Department, Woods Hole Oceanographic Institution, MS 21, 266 Woods Hold Rd., Woods Hole, MA, 02543, USA. 5. Fisheries Resources and Environmental Research Division, East Sea Fisheries Research Institute, National Institute of Fisheries Science, Gangneung, 25435, South Korea. 6. Department of Marine Science, Incheon National University, Incheon, 22012, South Korea. ilnamkim@inu.ac.kr.
Abstract
The western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N2O) cycles from greenhouse gases. We investigated WAO N2O dynamics through an intensive and precise N2O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0-50 m) and deep layers (200-2200 m) of the northern Chukchi Sea with an under-saturation of N2O. By contrast, both the surface layer (0-50 m) of the southern Chukchi Sea and the intermediate (50-200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N2O production (i.e., through nitrification), with N2O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N2O (mean: + 2.3 ± 2.7 μmol N2O m-2 day-1), whereas the northern region acted as a sink (mean - 1.3 ± 1.5 μmol N2O m-2 day-1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N2O "hot spot", and therefore, a key region requiring continued observations to both understand N2O dynamics and possibly predict their future changes.
The western Arctic Ocean (WAO) has experienced increased heat tranpan>sport into the region, sea-ice reduction, anpan>d chanpan>ges to the pan> class="Chemical">WAO nitrous oxide (N2O) cycles from greenhouse gases. We investigated WAO N2O dynamics through an intensive and precise N2O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0-50 m) and deep layers (200-2200 m) of the northern Chukchi Sea with an under-saturation of N2O. By contrast, both the surface layer (0-50 m) of the southern Chukchi Sea and the intermediate (50-200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N2O production (i.e., through nitrification), with N2O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N2O (mean: + 2.3 ± 2.7 μmol N2O m-2 day-1), whereas the northern region acted as a sink (mean - 1.3 ± 1.5 μmol N2O m-2 day-1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N2O "hot spot", and therefore, a key region requiring continued observations to both understand N2O dynamics and possibly predict their future changes.
Authors: Simon Yang; Bonnie X Chang; Mark J Warner; Thomas S Weber; Annie M Bourbonnais; Alyson E Santoro; Annette Kock; Rolf E Sonnerup; John L Bullister; Samuel T Wilson; Daniele Bianchi Journal: Proc Natl Acad Sci U S A Date: 2020-05-18 Impact factor: 11.205