Plutonium radioisotopes as radiotracers of sedimentation processes in the Black Sea coastal areas

IF 2.3 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research Pub Date : 2025-12-01 Epub Date: 2025-10-01 DOI:10.1016/j.csr.2025.105579

A.A. Paraskiv, N.N. Tereshchenko, V. Yu Proskurnin

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Abstract

The vertical distribution of plutonium radioisotopes (²³⁸Pu and ^239+240Pu) in five bottom sediment cores from the coastal marine area of Sevastopol Bay (the Black Sea) was studied. Based on the analysis of the ²³⁸Pu, ^239+240Pu activity and ²³⁸Pu/^239+240Pu activity ratio profiles, geochronological dating of bottom sediments was carried out and the main parameters of sedimentation processes (SR – sedimentation rate and MAR – mass accumulation rate) were calculated. It was found that each of the studied areas of the Sevastopol Bay has individual sedimentation features, which are reflected in SR and MAR values. SR values ranged from 2.5 to 7.5 mm year⁻¹ while MAR – from 1679 to 4833 g m⁻²·year⁻¹. The obtained results indicate that the intensity of water self-purification via plutonium removal into the sediments varies within the studied areas. It is shown that under the conditions of the spatiotemporal regime of plutonium input into the Black Sea it is possible to determine the SR and MAR for two time periods: 1962–1986 and 1986–2019. It has been established that on a half-century scale the SR and MAR have changed in the Sevastopol Bay. Thus, in the post-Chernobyl period, in the bay mouth, the SR and MAR increased by 2.1 and 1.8 times, respectively, while in the bay headwaters they decreased by 2.0 and 2.3 times, respectively. These changes are apparently a consequence of the construction of hydraulic structures both in the Sevastopol Bay and in its drainage basin.

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黑海沿岸地区沉积过程的放射性示踪剂钚放射性同位素

研究了黑海塞瓦斯托波尔湾沿海海域5个海底沉积物岩心中钚放射性同位素（238Pu和239+240Pu）的垂直分布。通过对238Pu、239+240Pu活度和238Pu/239+240Pu活度比值剖面的分析，进行了海底沉积物年代学测年，并计算了沉积过程的主要参数（SR -沉积速率和MAR -质量堆积速率）。研究发现，塞瓦斯托波尔湾每个研究区域都有各自的沉积特征，这些沉积特征反映在SR和MAR值上。SR值为2.5 ~ 7.5 mm year - 1， MAR -值为1679 ~ 4833 g m−2·year - 1。结果表明，在研究区域内，通过向沉积物中去除钚来实现水自净的强度是不同的。结果表明，在钚输入黑海的时空状态条件下，可以确定1962-1986年和1986-2019年两个时间段的SR和MAR。在半个世纪的尺度上，塞瓦斯托波尔湾的SR和MAR发生了变化。因此，在切尔诺贝利后时期，海湾口的SR和MAR分别增加了2.1和1.8倍，而海湾源头的SR和MAR分别减少了2.0和2.3倍。这些变化显然是在塞瓦斯托波尔湾及其流域建造水工结构的结果。

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来源期刊

Continental Shelf Research 地学-海洋学

CiteScore

4.30

自引率

4.30%

发文量

136

审稿时长

6.1 months

期刊介绍： Continental Shelf Research publishes articles dealing with the biological, chemical, geological and physical oceanography of the shallow marine environment, from coastal and estuarine waters out to the shelf break. The continental shelf is a critical environment within the land-ocean continuum, and many processes, functions and problems in the continental shelf are driven by terrestrial inputs transported through the rivers and estuaries to the coastal and continental shelf areas. Manuscripts that deal with these topics must make a clear link to the continental shelf. Examples of research areas include: Physical sedimentology and geomorphology Geochemistry of the coastal ocean (inorganic and organic) Marine environment and anthropogenic effects Interaction of physical dynamics with natural and manmade shoreline features Benthic, phytoplankton and zooplankton ecology Coastal water and sediment quality, and ecosystem health Benthic-pelagic coupling (physical and biogeochemical) Interactions between physical dynamics (waves, currents, mixing, etc.) and biogeochemical cycles Estuarine, coastal and shelf sea modelling and process studies.