Molybdenum (Mo) and thallium (Tl) are known as conservative-type elements in open ocean settings, despite their involvement in bio-cycling processes. In coastal oceans like the southern North Sea, however, positive and negative anomalies of dissolved Mo and Tl concentrations occur during certain time periods of the year, which are characterized by intensive organic matter cycling. The main motivation of the present study was to identify potential drivers for the non-conservative behavior of Mo and Tl. For this purpose, we conducted an indoor mesocosm experiment with natural seawater and sediment (including a natural microorganism community) and applied close to natural light and tidal (diurnal) conditions. After an incubation time of 35 days, we initialized a storm event to examine its influence on organic matter as well as nutrient and trace metal cycling. The temporal pattern of the inorganic macronutrients (N-species, dissolved phosphorous, dissolved silicate) as well as dissolved and particulate organic matter was highly dependent on the interplay of the phytoplankton and its associated bacteria bloom. Our results suggest that the redox-sensitive trace metals manganese (Mn), vanadium (V) and iron (Fe) were involved in bio-cycling processes. While temporal pattern of dissolved Mn and V were likely induced by active (macro-)nutrient assimilation rather than redox induced phase changes, dissolved Fe was present as organo-metallic complex and shielded from the flocculation as metal oxide. Our results further reveal positive Mo and negative Tl anomalies, especially during pre-storm conditions. The additional input of Mo was derived from the oxidation of reducing bottom sediments. Thereby, the degree as well as the rate of Mo-input was dependent on the composition of the background sediment. In the water column Mo was not only present in its dissolved oxidized form but was also stabilized by organic (algae-detritus, ligands) and inorganic (aluminosilicates) binding partners, preventing its (re-)deposition. Negative Tl anomalies were found to be induced by its immobilization by organic (algae-detritus, ligands) and inorganic (aluminosilicates) carrier phases in the water column prior to its deposition and potential fixation in the sulfidic bottom sediments. Particles derived from the storm event did not have any considerable effect on dissolved organic nor inorganic compounds, as they (re-)deposited before significant remineralization processes could take place.

尽管在海洋中钼（Mo）和th（Tl）参与生物循环过程，但它们仍被称为保守型元素。但是，在像北海南部这样的沿海海洋中，一年中的某些时段会发生溶解的Mo和Tl浓度的正异常和负异常，其特征是强烈的有机物循环。本研究的主要动机是确定Mo和Tl非保守行为的潜在驱动因素。为此，我们使用天然海水和沉积物（包括天然微生物群落）进行了室内介观试验，并在接近自然光和潮汐（昼夜）的条件下进行了试验。经过35天的潜伏期，我们初始化了一次风暴事件，以检查其对有机物以及养分和微量金属循环的影响。无机常量营养素（N种，溶解的磷，溶解的硅酸盐）以及溶解的和颗粒状的有机物的时间分布高度依赖于浮游植物及其相关细菌繁殖的相互作用。我们的结果表明，氧化还原敏感的痕量金属锰（Mn），钒（V）和铁（Fe）参与了生物循环过程。虽然溶解的Mn和V的时间模式很可能是由活性（宏观）养分吸收而不是由氧化还原诱导的相变诱导的，但溶解的Fe以有机金属络合物的形式存在，并以金属氧化物的形式被絮凝所屏蔽。我们的结果进一步揭示了正Mo和负Tl异常，特别是在暴风雨前。Mo的额外输入来自还原性底部沉积物的氧化。因此，Mo输入的程度和速率取决于背景沉积物的组成。在水柱中，Mo不仅以其溶解的氧化形式存在，而且还通过有机（藻类碎屑，配体）和无机（铝硅酸盐）结合伙伴而稳定，从而防止了其（再）沉积。发现负T1异常是由其在水柱中沉积和潜在固定在硫化底部沉积物中之前被有机（藻类碎屑，配体）和无机（硅铝酸盐）载体相固定化而引起的。风暴事件产生的粒子对溶解的有机或无机化合物均无明显影响，