{"title":"东京湾河口颗粒有机碳通量的时空变化。","authors":"Chiho Sukigara, Shigeyoshi Otosaka, Naho Horimoto-Miyazaki, Yoshihisa Mino","doi":"10.1007/s10872-022-00660-7","DOIUrl":null,"url":null,"abstract":"<p><p>A sediment trap experiment was conducted at a depth of 750 m at the mouth of Tokyo Bay to clarify the quantity and transport process of particles from the bay to the open ocean. The high total mass flux (8.7 ± 4.5 g m<sup>-2</sup> d<sup>-1</sup>) suggests that the particles not only originate in the surface layer right above the trap, but are also focused in Uraga Channel and discharged into the bay mouth. The organic carbon and nitrogen isotope ratios (δ<sup>13</sup>C<sub>org</sub>, δ<sup>15</sup>N) of the trapped particles were like those of the surface sediment in the bay, that is, a mixture of particles in rivers and suspended particles in the surface layer of the bay. Compared with the results of the experiment conducted in 1995-2002, the average total mass flux was reduced by 70% and organic carbon content was reduced by 50%. The δ<sup>13</sup>C<sub>org</sub> values of trapped particles were also lower than those observed in the previous experiment, indicating a lower contribution from surface-suspended particles with high δ<sup>13</sup>C<sub>org</sub> values in the bay. These results could partly reflect a decrease of the concentration of the suspended particulate carbon in the bay by half over 20 years. Another factor contributing to the decrease of the flux at the bay mouth would be that the intrusion of Kuroshio coastal water into the bay, which pushes particles out to the bay mouth, has not occurred in recent years.</p>","PeriodicalId":16640,"journal":{"name":"Journal of Oceanography","volume":"79 3","pages":"199-209"},"PeriodicalIF":1.3000,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9387886/pdf/","citationCount":"3","resultStr":"{\"title\":\"Temporal variation of particulate organic carbon flux at the mouth of Tokyo Bay.\",\"authors\":\"Chiho Sukigara, Shigeyoshi Otosaka, Naho Horimoto-Miyazaki, Yoshihisa Mino\",\"doi\":\"10.1007/s10872-022-00660-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>A sediment trap experiment was conducted at a depth of 750 m at the mouth of Tokyo Bay to clarify the quantity and transport process of particles from the bay to the open ocean. The high total mass flux (8.7 ± 4.5 g m<sup>-2</sup> d<sup>-1</sup>) suggests that the particles not only originate in the surface layer right above the trap, but are also focused in Uraga Channel and discharged into the bay mouth. The organic carbon and nitrogen isotope ratios (δ<sup>13</sup>C<sub>org</sub>, δ<sup>15</sup>N) of the trapped particles were like those of the surface sediment in the bay, that is, a mixture of particles in rivers and suspended particles in the surface layer of the bay. Compared with the results of the experiment conducted in 1995-2002, the average total mass flux was reduced by 70% and organic carbon content was reduced by 50%. The δ<sup>13</sup>C<sub>org</sub> values of trapped particles were also lower than those observed in the previous experiment, indicating a lower contribution from surface-suspended particles with high δ<sup>13</sup>C<sub>org</sub> values in the bay. These results could partly reflect a decrease of the concentration of the suspended particulate carbon in the bay by half over 20 years. Another factor contributing to the decrease of the flux at the bay mouth would be that the intrusion of Kuroshio coastal water into the bay, which pushes particles out to the bay mouth, has not occurred in recent years.</p>\",\"PeriodicalId\":16640,\"journal\":{\"name\":\"Journal of Oceanography\",\"volume\":\"79 3\",\"pages\":\"199-209\"},\"PeriodicalIF\":1.3000,\"publicationDate\":\"2023-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9387886/pdf/\",\"citationCount\":\"3\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Oceanography\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1007/s10872-022-00660-7\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"OCEANOGRAPHY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Oceanography","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s10872-022-00660-7","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"OCEANOGRAPHY","Score":null,"Total":0}
引用次数: 3
摘要
在东京湾入海口750 m深度进行了泥沙捕集器试验,以阐明东京湾入海颗粒的数量和输运过程。高质量通量(8.7±4.5 g m-2 d-1)表明颗粒不仅来自捕集器正上方的表层,而且集中在浦加水道并排入海湾口。捕获颗粒的有机碳氮同位素比值(δ13Corg, δ15N)与海湾表层沉积物相似,即河流颗粒与海湾表层悬浮颗粒的混合。与1995-2002年的试验结果相比,平均总质量通量减少了70%,有机碳含量减少了50%。被捕获颗粒的δ13Corg值也低于之前的实验值,表明海湾中高δ13Corg值的表面悬浮颗粒的贡献较小。这些结果可以部分反映海湾中悬浮颗粒碳的浓度在20年内减少了一半。导致河口通量减少的另一个因素可能是近年来没有发生黑潮沿岸水进入海湾,将颗粒推向海湾口的情况。
Temporal variation of particulate organic carbon flux at the mouth of Tokyo Bay.
A sediment trap experiment was conducted at a depth of 750 m at the mouth of Tokyo Bay to clarify the quantity and transport process of particles from the bay to the open ocean. The high total mass flux (8.7 ± 4.5 g m-2 d-1) suggests that the particles not only originate in the surface layer right above the trap, but are also focused in Uraga Channel and discharged into the bay mouth. The organic carbon and nitrogen isotope ratios (δ13Corg, δ15N) of the trapped particles were like those of the surface sediment in the bay, that is, a mixture of particles in rivers and suspended particles in the surface layer of the bay. Compared with the results of the experiment conducted in 1995-2002, the average total mass flux was reduced by 70% and organic carbon content was reduced by 50%. The δ13Corg values of trapped particles were also lower than those observed in the previous experiment, indicating a lower contribution from surface-suspended particles with high δ13Corg values in the bay. These results could partly reflect a decrease of the concentration of the suspended particulate carbon in the bay by half over 20 years. Another factor contributing to the decrease of the flux at the bay mouth would be that the intrusion of Kuroshio coastal water into the bay, which pushes particles out to the bay mouth, has not occurred in recent years.
期刊介绍:
The Journal of Oceanography is the official journal of the Oceanographic Society of Japan and open to all oceanographers in the world. The main aim of the journal is to promote understandings of ocean systems from various aspects including physical, chemical, biological, geological oceanography as well as paleoceanography, etc. The journal welcomes research focusing on the western North Pacific and Asian coastal waters, but the study region is not limited to the Asian Pacific. The journal publishes original articles, short contributions, reviews, and correspondence in oceanography and related fields.