Department of Oceanography, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan.
Ocean College, Zhejiang University, Zhoushan, 316021, Zhejiang, China.
Sci Rep. 2021 Mar 3;11(1):5080. doi: 10.1038/s41598-021-84420-5.
The Kuroshio-literally "the Black Stream"-is the most substantial current in the Pacific Ocean. It was called the Black Stream because this oligotrophic current is so nutrient-poor in its euphotic zone that the water appears black without the influence of phytoplankton and the associated, often colored dissolved organic matter. Yet, below the euphotic layer, nutrient concentrations increase with depth while current speed declines. Consequently, a core of maximum nutrient flux, the so-called nutrient stream, develops at a depth of roughly between 200 and 800 m. This poorly studied nutrient stream transports nutrients to and supports high productivity and fisheries on the East China Sea continental shelf; it also transports nutrients to and promotes increased productivity and fisheries in the Kuroshio Extension and the subarctic Pacific Ocean. Three modes of the Kuroshio nutrient stream are detected off SE Taiwan for the first time: one has a single-core; one has two cores that are apparently separated by the ridge at 120.6-122° E, and one has two cores that are separated by a southward flow above the ridge. More importantly, northward nutrient transports seem to have been increasing since 2015 as a result of a 30% increase in subsurface water transport, which began in 2013. Such a nutrient stream supports the Kuroshio's high productivity, such as on the East China Sea continental shelf and in the Kuroshio Extension SE of Japan.
黑潮——字面意思是“黑色水流”——是太平洋中最主要的海流。它之所以被称为黑潮，是因为这个贫营养的海流在透光层中缺乏营养物质，以至于在没有浮游植物和相关的、通常带有颜色的溶解有机物的影响下，海水呈现出黑色。然而，在透光层以下，营养物质浓度随着深度的增加而增加，而海流速度则下降。因此，在大约 200 到 800 米的深度形成了一个最大营养通量的核心，即所谓的营养流。这个研究较少的营养流将营养物质输送到东海大陆架，并支持那里的高生产力和渔业；它还将营养物质输送到黑潮延伸区和亚北极太平洋，促进那里生产力的提高和渔业的发展。台湾东南首次检测到黑潮营养流的三种模式：一种模式有一个单核心；一种模式有两个核心，这两个核心显然是由 120.6-122°E 的山脊隔开的；还有一种模式有两个核心，它们被山脊上方的南向流隔开。更重要的是，自 2015 年以来，由于 2013 年开始的次表层水输送增加了 30%，向北的营养输送似乎一直在增加。这种营养流支持了黑潮的高生产力，如东海大陆架和日本以东的黑潮延伸区。
