Programa de Pós Graduação em Ecologia, Conservação e Manejo da Vida Silvestre, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Programa de Pós Graduação em Ecologia, Conservação e Manejo da Vida Silvestre, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Environ Pollut. 2021 Jan 1;268(Pt B):115704. doi: 10.1016/j.envpol.2020.115704. Epub 2020 Sep 23.
Aquaculture impacts on aquatic organic matter and ecosystem integrity are poorly understood, especially in tropical regions. Here, we investigated the impacts of Nile tilapia net cage farming on the elemental stoichiometry, fluorescence components, and stable isotopes of dissolved organic matter (DOM) of the large, tropical Furnas Reservoir (SE Brazil). Early-stage fish farming, i.e., relatively small and recently implemented farms, had detectable incipient effects on DOM characteristics, and these effects differed between reservoir branches. In the less eutrophic Rio Grande branch of the reservoir, we found a reduction in natural humic-like DOM components and an increase in a protein-like DOM component as far as 100 m away from fish farms. Further, we observed a decrease in δN-TDN due to fish farming. In the more eutrophic Rio Sapucaí branch, there were only local decreases in C:N ratios, as well as rises in C:P and N:P of DOM due to fish farming. These results suggest that early-stage fish farming had local but detectable effects on aquatic DOM that depended on previous eutrophication levels and highlight the need to assess the early impacts of fish farming on tropical reservoirs by combining different monitoring strategies.
水产养殖对水生有机物质和生态系统完整性的影响尚未被充分了解，特别是在热带地区。在这里，我们研究了尼罗罗非鱼网箱养殖对大型热带富尔纳斯水库（巴西东南部）的溶解性有机物质（DOM）的元素化学计量、荧光成分和稳定同位素的影响。早期的鱼类养殖，即相对较小且最近实施的养殖场，对 DOM 特性产生了可检测的初期影响，而且这些影响在水库的不同分支之间有所不同。在富营养化程度较低的 Rio Grande 支流水库中，我们发现离养殖场 100 米远的地方，天然腐殖质样 DOM 成分减少，而类似于蛋白质的 DOM 成分增加。此外，我们还观察到由于鱼类养殖，δN-TDN 减少。在富营养化程度较高的 Rio Sapucaí 支流水库中，只有 DOM 的 C:N 比局部降低，以及由于鱼类养殖导致的 C:P 和 N:P 升高。这些结果表明，早期的鱼类养殖对水生 DOM 产生了局部但可检测的影响，这取决于先前的富营养化水平，并强调需要通过结合不同的监测策略来评估鱼类养殖对热带水库的早期影响。
