Abstract：
A Closed Aquatic Ecosystem (CAES) housed an aquatic plant Ceratophyllum demersum, zebrafish (Danio rerio), and microbes that were simultaneously obtained with the zebrafish, and it was used to study the operation of the ecosystem. The results indicated that the CAES can operate steadily for about 4 weeks. The dissolved oxygen (DO), pH, and conductivity values of the ecosystem regularly oscillated, while the total nitrogen of the water decreased and the total phosphate slightly increased. Additionally, the chemical oxygen demand (COD, a measure of organic compounds) of the water after the experiment increased to 39 times more than that of the water before the experiment. The meta-genomic data showed that the number of genera decreased by 38 % and the top 10 most abundant genera were almost completely different before and after the experiment, which demonstrated a great shift in the microbes during the operation process. These results suggested that although the CAES operated steadily during the 28-day experiment, there were more organic materials and less nitrogen in the water by the end of the experiment, which may have influenced the structure and operation of the ecosystem. Thus, it is necessary to remove superfluous plant biomass from the CAES and supply nitrogen to keep the ecosystem stable.
摘要：
封闭的水生生态系统（CAES）容纳了水生植物角藻，斑马鱼（Daniorerio），和斑马鱼同时获得的微生物，它被用来研究生态系统的运作。结果表明，CAES可以稳定运行约4周。溶解氧（DO），pH值,生态系统的电导率值经常波动，而水中的总氮减少，总磷酸盐略有增加。此外,化学需氧量(COD，有机化合物的量度）实验后的水增加到实验前的水的39倍。元基因组数据显示，属的数量减少了38％，前10个最丰富的属在实验前后几乎完全不同，这表明在操作过程中微生物发生了巨大的变化。这些结果表明，尽管CAES在28天的实验中运行稳定，实验结束时，水中的有机物质更多，氮更少，这可能影响了生态系统的结构和运行。因此，有必要从CAES中去除多余的植物生物量并供应氮以保持生态系统的稳定。
