Coastal marine ecosystems are strongly influenced by different occasional events, such as intense winds, mixing, rain and river discharges. These events can directly or indirectly cause changes in dissolved organic matter (DOM) quality through a cascade of different biotic and abiotic processes. The changes in DOM quality are often associated with changes in DOM optical properties. Thus, examining the dynamics of chromophoric DOM (CDOM) can provide valuable information about biological and physical processes that have occurred in the ecosystem. Episodic meteorological events, particularly in temperate areas, appear very abruptly and induce very rapid responses; therefore, high time-resolved measurements are needed to capture them. We used a weekly sampling scheme to characterize DOM and nutrient dynamics in the NW Mediterranean coastal station ‘SOLA’. From February 2013 to April 2014, we measured several physical and chemical variables including temperature, salinity, inorganic nutrients, chlorophyll a dissolved organic carbon (DOC), CDOM and fluorescent DOM (FDOM). During this period, two extremely high fresh water intrusions greatly influenced the dynamics of some DOM fractions, in particular the FDOM. Inorganic nutrients and chlorophyll a shown seasonal patterns: A winter period characterized by a high nutrient concentration in surface waters favored the phytoplankton spring bloom; then, summer stratification that extended until autumn. This stratification leads to nutrient depletion and, consequently, lower chlorophyll a values in the photic zone. The CDOM and FDOM optical active fractions did not follow temporal trends similar to the total DOC. This was likely because the potential sources and sinks of these DOM pools are microbial activity and light exposure, and these were acting simultaneously but in opposite directions. Interestingly, DOC exhibited the highest concentrations in summer, coinciding with nutrient and chlorophyll a minima. To explain this mismatch, we propose a sequence of abiotic and biotic phenomena that drive DOC temporal dynamics.

沿海海洋生态系统受到各种偶然事件的强烈影响，例如强风，混合，降雨和河流排放。这些事件可以通过一系列不同的生物过程和非生物过程直接或间接引起溶解有机物（DOM）质量的变化。DOM质量的变化通常与DOM光学特性的变化相关。因此，检查发色DOM（CDOM）的动力学可以提供有关生态系统中发生的生物和物理过程的有价值的信息。突发性气象事件，特别是在温带地区，突然出现并引起非常迅速的反应。因此，需要高时间分辨的测量来捕获它们。我们使用每周抽样方案来表征西北地中海沿岸站“ SOLA”中的DOM和养分动态。从2013年2月到2014年4月，我们测量了一些物理和化学变量，包括温度，盐度，无机养分，叶绿素一溶解的有机碳（DOC），CDOM和荧光DOM（FDOM）。在此期间，两次极高的淡水入侵极大地影响了某些DOM组分（尤其是FDOM）的动力学。无机养分和叶绿素一个示出季节模式：所述的冬季期间，其特征在于在表层水高营养物浓度的青睐浮游植物弹簧开花; 然后，夏季分层一直延伸到秋季。这种分层会导致营养物质的消耗，进而降低叶绿素a区域的数值。CDOM和FDOM光学活性成分未遵循类似于总DOC的时间趋势。这可能是因为这些DOM池的潜在源和汇是微生物活动和光照，并且它们同时作用但方向相反。有趣的是，DOC在夏季表现出最高的浓度，与养分和叶绿素的最小值相吻合。为了解释这种不匹配，我们提出了一系列驱动DOC时间动态的非生物和生物现象。