Wang Yang, Li Guangbo, Ji Qixing
Earth, Ocean and Atmospheric Sciences Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511458, China.
Division of Emerging Interdisciplinary Areas, Academy of Interdisciplinary Studies, The Hong Kong University of Science and Technology, Hong Kong 999077, China.
Water Res X. 2024 Aug 22;25:100249. doi: 10.1016/j.wroa.2024.100249. eCollection 2024 Dec 1.
The rapid expansion of coastal aquaculture has led to an increase in the coverage of aquaculture ponds, where intense feed-derived nitrogen is causing significant emissions of nitrous oxide (NO). Multiple NO production pathways and the relative importance of water column vs. sedimentary production in aquaculture ponds remain uncertain. Clarifying these pathways is vital for sustainable aquaculture development. Using N-labeled dissolved inorganic nitrogen, the pathways and rates of NO production in subtropical aquaculture ponds located in south China, cultivating whiteleg shrimp, Japanese seabass, and giant river prawn, were successfully characterized. Total NO production rates ranged from 6 to 70 µmol-N m d, with the shrimp pond exhibiting the highest total NO production rates, followed by ponds for seabass and prawn. These differences are primarily due to varying feed amounts causing differences in dissolved nutrients in water column and sediment. Particularly, nutrient and organic matter accumulation at the surface sediment stimulated NO production. The oxygenated sediment on a centimeter scale could produce substantially more NO compared to the water column above on a meter scale. Partial denitrification, i.e., nitrate and nitrite reduction to NO, was more important (> 60 %) for NO production in aquaculture ponds. The availability of nitrite is likely a major factor driving partial denitrification for both sedimentary and water column NO production.
沿海水产养殖的迅速扩张导致了养殖池塘面积的增加，在这些池塘中，来自饲料的大量氮正导致一氧化二氮（N₂O）的大量排放。水产养殖池塘中多种N₂O产生途径以及水柱与沉积物产生的相对重要性仍不确定。明确这些途径对于可持续水产养殖发展至关重要。利用氮标记的溶解无机氮，成功地确定了中国南方养殖凡纳滨对虾、日本鲈鱼和罗氏沼虾的亚热带水产养殖池塘中N₂O的产生途径和速率。N₂O的总产生速率范围为6至70 μmol-N m⁻² d⁻¹，对虾池塘的N₂O总产生速率最高，其次是鲈鱼和对虾池塘。这些差异主要是由于饲料量不同导致水柱和沉积物中溶解养分存在差异。特别是，表层沉积物中的养分和有机物质积累刺激了N₂O的产生。与一米尺度的水柱相比，厘米尺度的有氧沉积物能产生更多的N₂O。部分反硝化作用，即将硝酸盐和亚硝酸盐还原为N₂O，在水产养殖池塘的N₂O产生中更为重要（>60%）。亚硝酸盐的可用性可能是驱动沉积物和水柱中N₂O产生的部分反硝化作用的主要因素。
