The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Department of Animal Sciences, P.O. Box 12, Rehovot 76100, Israel.
Water Res. 2011 Mar;45(7):2375-82. doi: 10.1016/j.watres.2011.01.021. Epub 2011 Feb 21.
Interest in mariculture systems will rise in the near future due to the decreased ability of the ocean to supply the increasing demand for seafood. We present a trace study using stable carbon and nitrogen isotopes and chemical profiles of a zero-discharge mariculture system stocked with the gilthead seabream (Sparus aurata). Water quality maintenance in the system is based on two biofiltration steps. Firstly, an aerobic treatment step comprising a trickling filter in which ammonia is oxidized to nitrate. Secondly, an anaerobic step comprised of a digestion basin and a fluidized bed reactor where excess organic matter and nitrate are removed. Dissolved inorganic carbon and alkalinity values were higher in the anaerobic loop than in the aerobic loop, in agreement with the main biological processes taking place in the two treatment steps. The δ13C of the dissolved inorganic carbon (δ13C(DIC)) was depleted in 13C in the anaerobic loop as compared to the aerobic loop by 2.5-3‰. This is in agreement with the higher dissolved inorganic carbon concentrations in the anaerobic loop and the low water retention time and the chemolithotrophic activity of the aerobic loop. The δ13C and δ15N of organic matter in the mariculture system indicated that fish fed solely on feed pellets. Compared to feed pellets and particulate organic matter, the sludge in the digestion basin was enriched in 15N while δ13C was not significantly different. This latter finding points to an intensive microbial degradation of the organic matter taking place in the anaerobic treatment step of the system.
由于海洋供应海鲜的能力下降，满足日益增长的海鲜需求的能力下降，对海水养殖系统的兴趣将在不久的将来增加。我们提出了一项使用稳定的碳和氮同位素以及零排放海水养殖系统中储存的金头鲷（Sparus aurata）的化学特征的示踪研究。该系统的水质维护基于两个生物过滤步骤。首先，有氧处理步骤包括一个滴滤池，其中氨被氧化为硝酸盐。其次，厌氧步骤包括消化池和流化床反应器，其中去除过量的有机物和硝酸盐。与两个处理步骤中发生的主要生物过程一致，厌氧循环中的溶解无机碳和碱度值高于有氧循环。与有氧循环相比，厌氧循环中的溶解无机碳（δ13C(DIC)）的δ13C 被消耗了 2.5-3‰。这与厌氧循环中较高的溶解无机碳浓度以及有氧循环中的低水保留时间和化能自养活性一致。海水养殖系统中有机物的 δ13C 和 δ15N 表明，鱼仅以饲料颗粒为食。与饲料颗粒和颗粒有机物相比，消化池中的污泥在 15N 中富集，而 δ13C 没有明显差异。这一发现表明，在系统的厌氧处理步骤中，有机物发生了强烈的微生物降解。
