In the so-called “anomalous” summer in 2017, an increased concentration of DOC was measured in the entire water column at the station SJ107 in the eastern part of the Po River delta-Rovinj transect (Graphical abstract) in the northern Adriatic (NAd). Surface DOC ranged between 1.56 and 3.10 mg l⁻¹, being 2.5 times higher than the long-term (1989–2017) average for the same area. Such enlarged concentration of DOC, typical for eutrophic lagoons or lakes and not for open waters, was most probably a consequence of an intensive bloom of Mnemiopsis leidyi, which was recorded with an exceptionally high population density (up to 76 ind. m⁻³) in the same waters.

The number of jelly combs showed a decrease from the east (SJ107) to the west (SJ101) of the transect (Graphical abstract). Abundance in the central part of the transect was also quite low. Maximum of DOC corresponded with the abundance of the M. leidyi smallest specimens (<3 cm). At the western station of the same profile (SJ101), M. leidyi abundance was insignificant, and DOC concentration appeared to be controlled by seasonal changes in primary production and grazing activities. In contrast, at the eastern station (SJ107), changes in the complex food web interaction shaped the DOC quantity and its quality. A large fraction of DOC at both stations was found to be reactive, significantly contributing to the organic matter pool represented by surface-active substances (SAS).

A large anticyclonic gyre which developed from April to November in 2017 in the area of SJ107, supported calm water column conditions and abundant resources of zooplankton, which could support the residence and accumulation of the invasive ctenophore M. leidyi. For the first time, the presence of a long-lasting gyre (duration of at least 4 months) is documented both with hydrographic measurements and by numerical modelling. Such situation characterised by the production of highly reactive DOC leads to an extreme eutrophic episode.

A dispersion model indicated a high probability of M. leidyi spreading by the end of winter from the Venice lagoon, its hypothetical winter residing area, to the Istrian coast (Croatia).

在 2017 年所谓的“异常”夏季，在亚得里亚海北部 (NAd) 波河三角洲-罗维尼断面（图形摘要）东部的 SJ107 站的整个水体中测量到 DOC 浓度增加）。表面 DOC 介于 1.56 和 3.10 mg l ^{-1 之间}，比同一地区的长期（1989-2017）平均值高 2.5 倍。富营养化泻湖或湖泊而不是开放水域的 DOC 浓度如此扩大，很可能是Mnemiopsis leidyi密集开花的结果，记录了异常高的种群密度（高达 76 ind. m ^-3）在同一个水域。

果冻梳的数量从横断面的东（SJ107）到西（SJ101）呈减少趋势（图形摘要）。断面中心部分的丰度也很低。DOC 的最大值对应于M. leidyi最小标本 (<3 cm)的丰度。在同一剖面的西台站（SJ101），雷帝木丰度不显着，DOC浓度似乎受初级生产和放牧活动季节性变化的控制。相比之下，在东站（SJ107），复杂食物网相互作用的变化塑造了 DOC 的数量和质量。发现两个站点的大部分 DOC 具有反应性，对以表面活性物质 (SAS) 为代表的有机物质库有显着贡献。

2017年4月至11月在SJ107地区发展的大型反气旋环流，支持平静的水体条件和丰富的浮游动物资源，可以支持入侵的栉水母M. leidyi的栖息和聚集。首次通过水文测量和数值模拟记录了长期环流（持续时间至少 4 个月）的存在。这种以产生高反应性 DOC 为特征的情况会导致极端的富营养化事件。

扩散模型表明，莱迪伊蚊在冬季结束时从威尼斯泻湖（其假设的冬季居住区）传播到伊斯特拉海岸（克罗地亚）的可能性很高。