Fouilland E, Trottet A, Alves-de-Souza C, Bonnet D, Bouvier T, Bouvy M, Boyer S, Guillou L, Hatey E, Jing H, Leboulanger C, Le Floc'h E, Liu H, Mas S, Mostajir B, Nouguier J, Pecqueur D, Rochelle-Newall E, Roques C, Salles C, Tournoud M-G, Vasseur C, Vidussi F
UMR 9190 MARBEC Marine Biodiversity, Exploitation and Conservation, CNRS, IRD, IFREMER, Université de Montpellier, Montpellier & Sète, France.
DHI Water & Environment (S) Pte Ltd, 1 Cleantech loop #03-05 Clean Tech One, Singapore, 637141, Singapore.
Microb Ecol. 2017 Aug;74(2):289-301. doi: 10.1007/s00248-017-0962-6. Epub 2017 Mar 16.
Rivers are known to be major contributors to eutrophication in marine coastal waters, but little is known on the short-term impact of freshwater surges on the structure and functioning of the marine plankton community. The effect of adding river water, reducing the salinity by 15 and 30%, on an autumn plankton community in a Mediterranean coastal lagoon (Thau Lagoon, France) was determined during a 6-day mesocosm experiment. Adding river water brought not only nutrients but also chlorophyceans that did not survive in the brackish mesocosm waters. The addition of water led to initial increases (days 1-2) in bacterial production as well as increases in the abundances of bacterioplankton and picoeukaryotes. After day 3, the increases were more significant for diatoms and dinoflagellates that were already present in the Thau Lagoon water (mainly Pseudo-nitzschia spp. group delicatissima and Prorocentrum triestinum) and other larger organisms (tintinnids, rotifers). At the same time, the abundances of bacterioplankton, cyanobacteria, and picoeukaryote fell, some nutrients (NH, SiO) returned to pre-input levels, and the plankton structure moved from a trophic food web based on secondary production to the accumulation of primary producers in the mesocosms with added river water. Our results also show that, after freshwater inputs, there is rapid emergence of plankton species that are potentially harmful to living organisms. This suggests that flash flood events may lead to sanitary issues, other than pathogens, in exploited marine areas.
河流被认为是造成海洋沿海水域富营养化的主要因素，但对于淡水涌入对海洋浮游生物群落结构和功能的短期影响却知之甚少。在一项为期6天的中宇宙实验中，研究了添加河水（盐度降低15%和30%）对法国地中海沿岸泻湖（托湖）秋季浮游生物群落的影响。添加河水不仅带来了营养物质，还带来了在半咸水中无法存活的绿藻。加水导致细菌产量在最初（第1 - 2天）增加，同时浮游细菌和微微型真核生物的丰度也增加。第3天后，对于托湖水中已有的硅藻和甲藻（主要是纤细拟菱形藻和三角原甲藻）以及其他较大生物（钟形虫、轮虫）的增加更为显著。与此同时，浮游细菌、蓝细菌和微微型真核生物的丰度下降，一些营养物质（NH、SiO）恢复到输入前的水平，并且在添加河水的中宇宙中，浮游生物结构从基于次级生产的营养食物网转变为初级生产者的积累。我们的结果还表明，淡水输入后，可能对生物体有害的浮游生物物种迅速出现。这表明除病原体外，洪水事件可能导致开发的海洋区域出现卫生问题。
