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One-dimensional mass budget of 210Pb in the western Northwest Pacific Ocean
https://repo.qst.go.jp/records/68870
https://repo.qst.go.jp/records/6887071e53e3d-722b-4b66-96ba-e407b9cc4e14
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2007-03-12 | |||||
| タイトル | ||||||
| タイトル | One-dimensional mass budget of 210Pb in the western Northwest Pacific Ocean | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Yamada, Masatoshi
× Yamada, Masatoshi× Zheng, Jian× 山田 正俊× 鄭 建 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 210Pb is a naturally occurring radionuclide with a half-life of 22.3 years; its significant sources for seawaters are atmospheric input and in situ production by decay of 226Ra. A mooring of three time-series sediment traps was deployed at two sites in the western Northwest Pacific Ocean for nine months. Total mass fluxes and 210Pb activities were determined for the settling particles to elucidate their scavenging and transport processes. Sediment samples also were analyzed for 210Pb activities. The mass balance of 210Pb at each sediment trap experiment site can be calculated from the total supply of 210Pb to the water column and the loss of 210Pb by radioactive decay in the water column. The total supply of 210Pb to the water column is calculated as the sum of the 210Pb production rate by decay of 226Ra within the water column and the input rate of 210Pb from the atmosphere. The loss of 210Pb is given by the radioactive decay rate of 210Pb calculated from the 210Pb water column inventory. The difference between the total supply and loss of 210Pb by radioactive decay represents the amount of 210Pb removed by settling particles; this is called the 210Pb deficiency flux. The ratios of the observed 210Pb fluxes to the 210Pb deficiency fluxes in the upper traps at the two sites were only 0.02 and 0.12. These extremely low 210Pb trapping ratios may be attributed to a substantial part of 210Pb derived from the atmosphere being advectively exported from the surface waters of these sites. Those ratios in the near-bottom traps ranged between 1.2 and 2.6. This suggests that these high ratios are due to effective particle scavenging, large lateral 210Pb import to the near-bottom trap and/or input of resuspended particles that have not become incorporated into the sediments. The 210Pb activities in the surficial sediments were much lower than those in the near-bottom traps. The 210Pb accumulation rates estimated from the excess 210Pb inventory in the sediment column were 40 % - 70 % higher than the mean 210Pb fluxes at the near-bottom traps. Data on 210Pb activities in settling particles and activities of 210Pb in surficial sediments and their fluxes in the western Northwest Pacific Ocean have provided important keys for appreciating the processes controlling transport and scavenging of reactive radionuclides at the near-bottom. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | SOLAS Open Science Conference | |||||
| 発表年月日 | ||||||
| 日付 | 2007-03-09 | |||||
| 日付タイプ | Issued | |||||
