PDF(Pubmed)
Abstract：
Dissolved oxygen is fundamental for chemical and biochemical processes occurring in natural waters and critical for the life of aquatic organisms. Many organisms are responsible for altering organic matter and oxygen transfers across ecosystem or habitat boundaries and, thus, engineering the oxygen balance of the system. Due to such Lemna features as small size, simple structure, vegetative reproduction and rapid growth, as well as frequent mass occurrence in the form of thick mats, they make them very effective in oxygenating water. The research was undertaken to assess the impact of various species of duckweed (L. minor and L. trisulca) on dissolved oxygen content and detritus production in water and the role of ecological factors (light, atmospheric pressure, conductivity, and temperature) in this process. For this purpose, experiments were carried out with combinations of L. minor and L. trisulca. On this basis, the content of oxygen dissolved in water was determined depending on the growth of duckweed. Linear regression models were developed to assess the dynamics of changes in oxygen content and, consequently, organic matter produced by the Lemna. The research showed that the presence of L. trisulca causes an increase in dissolved oxygen content in water. It was also shown that an increase in atmospheric pressure had a positive effect on the ability of duckweed to produce oxygen, regardless of its type. The negative correlation between conductivity and water oxygenation, obtained in conditions of limited light access, allows us to assume that higher water conductivity limits oxygen production by all combinations of duckweeds when the light supply is low. Based on the developed models, it was shown that the highest increase in organic matter would be observed in the case of mixed duckweed and the lowest in the presence of the L. minor species, regardless of light conditions. Moreover, it was shown that pleustophytes have different heat capacities, and L. trisulca has the highest ability to accumulate heat in water for the tested duckweed combinations. The provided knowledge may help determine the good habitat conditions of duckweed, indicating its role in purifying water reservoirs as an effect of producing organic matter and shaping oxygen conditions with the participation of various Lemna species.
摘要：
溶解氧是自然水域中发生的化学和生化过程的基础，对水生生物的生命至关重要。许多生物负责改变生态系统或栖息地边界之间的有机物和氧气转移，因此，设计系统的氧气平衡。由于浮萍的特点，如体积小，结构简单,营养繁殖和快速生长，以及经常以厚垫子的形式出现的质量，它们使它们在充氧水中非常有效。进行这项研究是为了评估各种浮萍的影响（L.minor和L.trisulca)对水中溶解氧含量和碎屑产生以及生态因素(光，大气压力,电导率，和温度)在这个过程中。为此,用L.minor和L.trisulca的组合进行实验。在此基础上,根据浮萍的生长情况确定水中溶解氧的含量。开发了线性回归模型来评估氧含量变化的动力学，因此,浮萍产生的有机物。研究表明，三磺乳杆菌的存在会导致水中溶解氧含量的增加。还表明，大气压的增加对浮萍产生氧气的能力有积极影响，不管它的类型。电导率与水的氧合呈负相关,在有限的光线条件下获得，允许我们假设，当光供应较低时，较高的水电导率限制了所有组合的浮萍产生的氧气。基于开发的模型，研究表明，在混合浮萍的情况下，有机物的增加最高，而在存在L.minor种的情况下，有机物的增加最低。不管光线条件如何。此外，研究表明，绿藻具有不同的热容量，对于测试的浮萍组合，三磺乳杆菌在水中积累热量的能力最高。提供的知识可能有助于确定浮萍的良好栖息地条件，表明其在净化水库中的作用是在各种浮萍物种的参与下产生有机物和塑造氧气条件的作用。
