The impact of multiple environmental and anthropogenic stressors on the marine environment remains poorly understood. Therefore, we studied the contribution of environmental variables to the densities and gene expression of the dominant zooplankton species in the Belgian part of the North Sea, the calanoid copepod Temora longicornis. We observed a reduced density of copepods, which were also smaller in size, in samples taken from nearshore locations when compared to those obtained from offshore stations. To assess the factors influencing the population dynamics of this species, we applied generalised additive models. These models allowed us to quantify the relative contribution of temperature, nutrient levels, salinity, turbidity, concentrations of photosynthetic pigments, as well as chemical pollutants such as polychlorinated biphenyls and polycyclic aromatic hydrocarbons (PAHs), on copepod density. Temperature and Secchi depth, a proxy for turbidity, were the most important environmental variables predicting the densities of T. longicornis, followed by summed PAH and chlorophyll concentrations. Analysing gene expression in field‐collected adults, we observed significant variation in metabolic and stress‐response genes. Temperature correlated significantly with genes involved in proteolytic activities, and encoding heat shock proteins. Yet, concentrations of anthropogenic chemicals did not induce significant differences in the gene expression of genes involved in the copepod's fatty acid metabolism or well‐known stress‐related genes, such as glutathione transferases or cytochrome P450. Our study highlights the potential of gene expression biomonitoring and underscores the significance of a changing environment in future studies.

中文翻译：

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联合应激源对北海桡足类 Temora longicornis 密度和基因表达动态的贡献

多种环境和人为压力因素对海洋环境的影响仍然知之甚少。因此，我们研究了环境变量对北海比利时部分主要浮游动物物种——桡足类桡足类——密度和基因表达的贡献。长角鲽鱼。我们观察到，与从近海站点采集的样本相比，从近岸地点采集的样本中桡足类动物的密度有所降低，而且尺寸也较小。为了评估影响该物种种群动态的因素，我们应用了广义相加模型。这些模型使我们能够量化温度、营养水平、盐度、浊度、光合色素浓度以及化学污染物（如多氯联苯和多环芳烃（PAH））对桡足类密度的相对贡献。温度和 Secchi 深度（浊度的代表）是预测密度的最重要的环境变量。长角砗磲，然后是 PAH 和叶绿素浓度的总和。通过分析现场收集的成年人的基因表达，我们观察到代谢和应激反应基因的显着变化。温度与参与蛋白水解活性和编码热休克蛋白的基因显着相关。然而，人为化学物质的浓度并没有导致参与桡足类脂肪酸代谢的基因或众所周知的应激相关基因（例如谷胱甘肽转移酶或细胞色素P450）的基因表达出现显着差异。我们的研究强调了基因表达生物监测的潜力，并强调了环境变化在未来研究中的重要性。