Abstract. In the upper layers of the Ionian Sea, young Mediterranean Atlantic Waters (MAW) flowing eastward from the Sicily channel meet old MAW. In May 2017, during the PEACETIME cruise, fluorescence and particle content sampled at high resolution revealed unexpected heterogeneity in the central Ionian. Surface salinity measurements, together with altimetry-derived and hull-mounted ADCP currents, describe a zonal pathway of AW entering the Ionian Sea, consistent with the so-called cyclonic mode in the North Ionian Gyre. The ION-Tr transect, located ~19–20° E–~36° N turned out to be at the crossroad of three water masses, mostly coming from the west, north and from an isolated anticyclonic eddy northeast of ION-Tr. Using Lagrangian numerical simulations, we suggest that the contrast in particle loads along ION-Tr originates from particles transported from these three different water masses. Waters from the west, identified as young AW carried by a strong southwestward jet, were intermediate in particle load, probably originating from the Sicily channel. Water mass originating from the north was carrying abundant particles, probably originating from northern Ionian, or further from the south Adriatic. Waters from the eddy, depleted in particles and Chl-a may originate from south of Peloponnese, where the Pelops eddy forms. The central Ionian Sea hence appears as a mosaic area, where waters of contrasted biological history meet. This contrast is particularly clear in spring, when blooming and non-blooming areas co-occur. Particle abundance in situ measurements are useful to discriminate water masses and derive circulation, together with T-S properties. Interpreting the complex dynamics of physical-biogeochemical coupling from discrete measurements made at isolated stations at sea is a big challenge. The combination of multi-parametric in situ measurements at high resolution with remote sensing and Lagrangian modeling appears as one proper way to address this challenge.

中文翻译：

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长距离粒子传输到爱奥尼亚海中部

摘要。在爱奥尼亚海的上层，从西西里河道向东流动的年轻地中海大西洋水域（MAW）与旧的MAW相遇。2017年5月，在PEACETIME巡游中，以高分辨率采样的荧光和颗粒含量显示出爱奥尼亚中部的意外异质性。地表盐度测量，以及高程派生的和安装在船体上的ADCP电流，描述了AW进入爱奥尼亚海的地带路径，这与北爱奥尼亚回旋带的所谓气旋模式一致。ION-Tr横断面位于E ~~ 19-20°～~ 36°N，是三个水团的交汇点，主要来自西部，北部和来自ION-Tr东北部一个孤立的反气旋涡。使用拉格朗日数值模拟，我们认为，沿ION-Tr的粒子负载的反差源自于这三种不同水团所传输的粒子。来自西部的水被确定为由强大的西南向射流运载的年轻AW，其颗粒负荷处于中等水平，可能源自西西里河道。来自北部的水团携带大量颗粒，可能来自爱奥尼亚州北部或亚得里亚海南部。来自涡流的水，其中的颗粒和Chl-a耗尽，可能来自伯罗奔尼撒南部，而伯罗奔尼撒形成了该区域。因此，爱奥尼亚海中部似乎是一个镶嵌区域，生物历史截然相反的水在这里汇合。在春季，当同时出现开花和非开花区域时，这种对比特别明显。颗粒丰度原位测量可用于区分水团和推导循环以及TS特性。从海上隔离站的离散测量结果解释物理-生物地球化学耦合的复杂动力学是一个巨大的挑战。高分辨率的多参数原位测量与遥感和拉格朗日建模相结合，似乎是应对这一挑战的一种合适方法。