NITROGENOUS NUTRIENT TRANSFORMATIONS IN THE SPRING AND FALL IN THE CHESAPEAKE BAY
NITROGENOUS NUTRIENT TRANSFORMATIONS IN THE SPRING AND FALL IN THE CHESAPEAKE BAY
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DOI：
10.1016/0272-7714(90)90004-b
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发表时间：
1990-04-01
影响因子：
2.8
通讯作者：
MALONE, T
中科院分区：
文献类型：
--
作者：
HORRIGAN, SG;MONTOYA, JP;MALONE, T
1984年春、秋航次，在切萨皮克湾主航道的一系列站位进行了浮游植物、浮游细菌、颗粒碳氮和无机氮溶解库的测定。在每一次航行中，我们对海湾的长轴(N-S)进行了两次横断面；比较这些横断面发现，O2、叶绿素a和溶解无机氮的水平和垂直分布在一天的时间尺度上可以发生巨大的变化。用15N标记的底物(NO2-、NO3-和NH4+)在部分站点上进行了实验。这些实验旨在测量溶解水池之间的氮通量以及通量颗粒。在春季巡航期间，发现粒子对NO2-的摄取率高得惊人。秋季，颗粒物的摄取更紧密地遵循了之前报道的模式。溶解的无机库之间的氮通量往往大于进入颗粒的通量。个别反应的速率在空间上是不同的，在整个水柱中经常发现显著的活动。在含氧量较高的水域中发生典型的厌氧反应表明，厌氧微区可能是海湾氮素转化的重要场所。我们的结果还表明，在秋季巡航期间，风暴引起的水柱混合极大地提高了许多微生物介导的过程的速率。这种短暂的强化可能会对氮循环产生巨大的、通常没有文献记载的影响。
Measurements of the standing stock of phytoplankton, bacterioplankton and particulate carbon and nitrogen, and dissolved pools of inorganic nitrogen were made at a series of stations located in the main channel of the Chesapeake Bay during cruises in the spring and fall of 1984. On each cruise, we conducted two transects of the long axis (N-S) of the bay; comparison of these transects revealed that the horizontal and vertical distribution of O2, chlorophyll a, and dissolved inorganic nitrogen can change dramatically on a time scale of days. Experiments were carried out with 15N-labelled substrates (NO2-, NO3-, and NH4+) at a subset of the stations. These experiments were designed to measure the fluxes of nitrogen between the dissolved pools as well as the flux particles. During the spring cruise, a suprisingly high rate of uptake of NO2- by particles was found. In the fall, uptake by particles followed previously reported patterns more closely. The flux of nitrogen between dissolved inorganic pools was often greater than the flux into particles. The rates of individual reactions varied spatially, and significant activity throughout the water column was often found. The occurrence of typically anaerobic reactions in well-oxygenated waters suggests that anaerobic microzones may be an important site for nitrogen transformations in the bay. Our results also indicate that the rates of a number of microbially-mediated processes were greatly enhanced by storm-induced mixing of the water column during our fall cruise. Such transient enhancements may have a large, and usually undocumented, effect on the nitrogen cycle.