The relevance of the BIOdiversity TO FUNction relationship in heterotrophic aquatic systems under stress (BIO2FUN)

外来有机物质，如凋落叶，是水生系统能量和营养的重要来源。储存在这些叶子中的能量和营养物质通过异养微生物（主要是一组特定的水生真菌）的活动被更广泛的食物网所获取。这些真菌通过释放酶直接降解叶片，或者通过脂质和蛋白质的浓度最终刺激叶片的消耗来间接提高叶片的营养质量。然而，叶片上的微生物群落组成受到人为来源的压力的改变，从而改变了这两种功能的实现程度。根据污染诱导的群落耐受性概念，这些群落通过以耐受性物种取代敏感物种来适应胁迫。因此，这些社区变得更加宽容，这可能是特定的压力源。在此背景下，BIO2FUN将在第一步评估复杂的原始微生物群落，以及那些适应有机微污染物和营养物质混合物的群落（应激源非特异性耐受性）或杀菌剂（应激源特异性耐受性），这些微生物群落分别来自废水处理厂流出物和葡萄园径流。将采用基于实验室的全因子试验设计，在暴露于不断增加的营养物和杀菌剂水平下评估这些群落的叶片分解效率。通过将这些反应与单个水生真菌物种的性状（例如酶库存量和氨基酸和脂肪酸组成形式的营养质量）联系起来，BIO2FUN有望解开其潜在机制。此外，这些变量允许对切碎机叶片的营养质量进行估计，这将最终通过评估无脊椎动物叶片切碎的生理后果进行实验验证。最终，拟议的项目将成为解释异养食物网中自下而上定向效应的未来研究的里程碑。

Allochthonous organic material, such as leaf litter, is a critical source of energy and nutrients in aquatic systems. The energy and nutrients stored in those leaves is made accessible for the wider food web through the activity of heterotrophic microorganisms, mainly a specific group of aquatic fungi. These fungi degrade leaves directly via the release of enzymes or indirectly by increasing the nutritious quality of leaves for shredders through the concentration of lipids and proteins ultimately stimulating leaf consumption. The microorganisms' community composition on leaves is, however, altered by stressors of anthropogenic origin modifying the extent to which these two functions are fulfilled. According to the pollution induced community tolerance concept, these communities adapt to stress by replacing sensitive with tolerant species. Thereby, these communities become more tolerant, which may be stressor specific. In this context, BIO2FUN will assess in a first step the stress tolerance of complex pristine microbial communities as well as those communities either adapted to a mixture of organic micropollutants and nutrients (stressor-unspecific tolerance) or fungicides (stressor-specific tolerance) originating from wastewater treatment plant effluents and vineyard runoff, respectively. Those communities' leaf decomposition efficiency will be assessed under exposure towards increasing levels of nutrients and fungicides using a full-factorial laboratory based test design. By linking these responses to traits (e.g. enzymatic inventory and nutritious quality in the form of amino and fatty acid compositions) of individual aquatic fungal species, BIO2FUN has the ambition to disentangle the underlying mechanisms. Moreover, those variables allow for an estimation of the nutritious quality of leaves for shredders, which will finally be verified experimentally by assessing physiological consequences in leaf shredding invertebrates. Ultimately, the proposed project will be a milestone for the interpretation of future studies on bottom-up directed effects in heterotrophic food webs.