Hanžek Nikola, Šiljeg Mario, Šikić Tanja, Stanković Igor
Josip Juraj Strossmayer Water Institute, Ulica grada Vukovara 220, 10000 Zagreb, Croatia.
Plants (Basel). 2024 Aug 14;13(16):2252. doi: 10.3390/plants13162252.
Phytoplankton is a polyphyletic group of organisms that responds rapidly to environmental conditions and provides a reliable response to changes, making it a good ecological indicator for water quality monitoring. However, a gradient is almost essential for a reliable relationship between pressure and impact. In a low-gradient environment, ingenuity is required to outsmart the limitations of the commonly used linear relationship. Here, we examine changes in biomass and functional biodiversity by analysing larger data sets (2013-2022) in six ecologically diverse, natural, deep Croatian karst lakes with low nutrient gradients using nonlinear correlation coefficients and multivariate analyses in 209 samples. We found that phytoplankton biomass was most strongly influenced by nutrients, salinity and alkalinity, while light availability and total nitrogen strongly influenced phytoplankton functional biodiversity. An additional analysis of the TN:TP ratio revealed that the oligotrophic Lake Vransko is nitrogen-limited, and lakes Kozjak and Prošće are phosphorus-limited. This further clarified the relationship of phytoplankton to nutrients despite the low gradient. The complex analysis in this study provides a new perspective for predicting changes in the structure and succession of phytoplankton in deep karst lakes for successful management under apparent anthropogenic pressure and climate change.
浮游植物是一组多源生物，对环境条件反应迅速，能对变化给出可靠响应，使其成为水质监测的良好生态指标。然而，对于压力与影响之间的可靠关系而言，梯度几乎必不可少。在低梯度环境中，需要发挥创造力来克服常用线性关系的局限性。在此，我们通过分析六个生态多样、自然、营养梯度低的克罗地亚喀斯特深湖（2013年至2022年）的更大数据集（209个样本），利用非线性相关系数和多变量分析来研究生物量和功能生物多样性的变化。我们发现，浮游植物生物量受营养物质、盐度和碱度影响最大，而光照可用性和总氮对浮游植物功能生物多样性影响强烈。对总氮与总磷比率的进一步分析表明，贫营养的弗兰斯科湖受氮限制，科扎克湖和普罗舍湖受磷限制。尽管梯度较低，但这进一步阐明了浮游植物与营养物质之间的关系。本研究中的复杂分析为预测喀斯特深湖浮游植物结构和演替变化提供了新视角，以便在明显的人为压力和气候变化下进行成功管理。
