OCEANIC STRATIFIED EUPHOTIC ZONE AS ELUCIDATED BY TH-234-U-238 DISEQUILIBRIA
OCEANIC STRATIFIED EUPHOTIC ZONE AS ELUCIDATED BY TH-234-U-238 DISEQUILIBRIA
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DOI：
10.4319/lo.1987.32.1.0189
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发表时间：
1987-01-01
影响因子：
4.5
通讯作者：
BRULAND, KW
中科院分区：
文献类型：
--
作者：
COALE, KH;BRULAND, KW
在墨西哥曼萨尼洛附近的Vertex 2和3站，以及夏威夷以北约900公里处的Vertex 4站[美国]，测定了溶解和颗粒234的分布。通过模拟234U和238U在溶解和颗粒状态下的不平衡，可以得到Th从溶解相到颗粒相的清扫率、颗粒停留时间和Th通过颗粒去除的通量的估计。234：238U活度比剖面表明，真光层可分为两层：上层贫营养层，新产值低，净清除能力低，溶解234次停留时间长；次表层富营养层，新产值高，清除强烈，溶解234次停留时间短。新的生产量，而不是总的初级生产量，可能决定海洋表层水中活性元素的净清除率。这些结果有助于对寡营养真光带分层结构的新描述，并支持这一概念，即这可能是全球分层少营养制度的普遍和普遍特征。这些分层系统不仅可以根据生物和营养参数来构建，还可以根据化学清除和元素传输的速率来构建。
Profiles of dissolved and particulate 234Th were determined at the VERTEX 2 and 3 stations off Manzanillo, Mexico, and at the VERTEX 4 station about 900 km north of Hawaii [USA]. By modelling the disequilibria between 234Th and 238U in the dissolved and particulate form, estimates of scavengin rates for Th from the dissolved to particulate phases, particle residence times, and the flux of Th via particle removal can be obtained. 234Th:238U activity ratio profiles indicate that the euphotic zone can be separated into two layers: An upper oligotrophic layer characterized by low new production values, low net scavenging, and long dissolved 234Th residence times; and a subsurface eutrophic layer with higher new production values, more intense scavenging, and shorter dissolved 234Th residence times. New production, rather than total primary production may determine net scavenging rates of reactive elements from oceanic surface waters. These results contribute to the emerging descriptions of the layered structure of oligotrophic euphotic zones and support the notion that this may be a general and ubiquitous feature of global stratified oligotrophic regimes. These layered systems can be structured not only in biological and nutrient parameters, but also in terms of the rates of chemical scavenging and elemental transport.