Microscale distribution of oxygen and nitrate in sediment inhabited by Nereis diversicolor:: spatial patterns and estimated reaction rates
Microscale distribution of oxygen and nitrate in sediment inhabited by Nereis diversicolor:: spatial patterns and estimated reaction rates
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DOI：
10.3354/ame034023
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发表时间：
2004-01-16
影响因子：
1.4
通讯作者：
Revsbech, NP
中科院分区：
文献类型：
--
作者：
Nielsen, OI;Gribsholt, B;Revsbech, NP
在丹麦 Limfjorden 的浅泥滩中，利用微型传感器测量了多毛沙蚕洞穴结构周围沉积物中的氧气和硝酸盐浓度。根据浓度分布计算并确定了洞穴结构和表面沉积物附近涉及氧气和硝酸盐的反应（耗氧、硝化和硝酸盐还原）的速率和空间分布。天然杂色猪笼草种群的洞穴壁使沉积物-水界面的表面积增加了几倍，并将具有高代谢活性的含氧微生态位引入了缺氧沉积物中。硝化和硝酸盐还原是空间上分离的过程，硝化仅限于0.9至1.5毫米厚的好氧区，而硝酸盐还原作为严格厌氧过程发生在靠近好氧区的含硝酸盐层中。在密度为 2560 个个体 m(-2) 的情况下，杂色猪笼草的洞穴壁分别占大量沉积物吸氧量的 12% 至 40%，以及大量硝化作用和硝酸盐还原作用的 50% 至 77% 和 58% 至 82%。因此，大型动物群的洞穴结构可能是参与氮循环的主要沉积物区室，并可能促进沉积物中生物可利用氮的损失。
Profiles of oxygen and nitrate were measured with microsensors in sediment surrounding burrow structures of the polychaete Nereis diversicolor in a shallow mudflat in Limfjorden, Denmark. Rates and spatial distribution of reactions involving oxygen and nitrate (oxygen consumption, nitrification and nitrate reduction) in the vicinity of burrow structures and surface sediment were calculated and identified from concentration profiles. The burrow walls of the natural N. diversicolor population increased the surface area of the sediment-water interface several-fold and introduced oxic microniches with high metabolic activity into otherwise anoxic sediment. Nitrification and nitrate reduction were spatially separated processes, with nitrification restricted to the 0.9 to 1.5 mm thick oxic zone and nitrate-reduction occurring as a strictly anaerobic process in the nitrate-containing layers next to the oxic zone. At a density of 2560 individuals m(-2), burrow walls of N. diversicolor account for 12 to 40 % of bulk sediment oxygen uptake and 50 to 77 % and 58 to 82 % of bulk nitrification and nitrate reduction, respectively. Thus, burrow structures of macro-infauna are potentially a major sediment compartment involved in nitrogen cycling and may promote loss of bioavailable nitrogen from the sediment.