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大型底栖动物对长江口潮滩沉积物-水界面无机氮交换的影响 总被引:16,自引:2,他引:14
基于实验模拟,通过对比分析潮滩无机氮长短期通量交换、循环规律及沉积物中无机氮的剖面特征在有/无底栖动物活动背景下的差异,探讨了双壳类底栖动物河蚬对长江口潮滩沉积物-水界面无机氮交换的影响及其机制.研究发现:潮滩无机氮界面交换中,河蚬的钻穴活动能增加向上覆水方向氨氮和硝氮的通量值;河蚬长期栖息对界面的生物扰动和代谢物排放能促进氨氮向上覆水的释放并逐渐加强沉积物氧化层中的硝化活动;界面附近河蚬的扰动和喷灌活动改变了沉积物中无机氮的垂直剖面特征,加速了沉积物中有机质的矿化分解和两相界面间氨氮的离子交换,促进沉积物氮库向滨岸水体的释放输出. 相似文献
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Gonzalez-Fernandez O Hidalgo M Margui E Carvalho ML Queralt I 《Environmental pollution (Barking, Essex : 1987)》2008,153(2):476-482
Every year between 8 and 9 millions of vehicles in the European Union arrive to their end of life. Car wastes can have a very high metal content, falling into hazardous waste class. A preliminary evaluation of these wastes could be made by metals' leaching test runs which is the main objective of the present study. Evaluation of the total metal content was carried out by X-ray fluorescence and the mobility of these metals using two simple standardized extractions such as the TCLP (Toxicity Characterisation Leaching Procedure) of the US EPA and the German leaching test DIN 38414-S4. Additionally, an extraction test with acetone was performed in order to recognise metals bounded to organic matter. The results show that the total metal content of the ASR can overpass the established values for inert residues. Lead and zinc contents are fairly well correlated with grain-size, whilst other metals' contents do not exhibit clear grain-size dependence. 相似文献
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据2016年胶州湾水质自动监测的数据结果,分析了水质变化趋势,并统计和评价其水质超标情况。结果表明:2016-04—11水质自动站海域溶解氧质量浓度和pH 的日均值均达到二类海水水质标准,达标率为100%;活性磷酸盐年均值为0.023mg/L,无机氮年均值为0.154mg/L,以硝酸盐为主(64.9%);无机氮和活性磷酸盐超标率均为16.7%,而且集中在降雨量较大的8月、9月,营养盐指标超标基本与海泊河的淡水输入有关;叶绿素a质量浓度与溶解氧、pH 和浊度呈显著正相关,浮游植物光合作用对该海域表层海水的水质参数影响较大;自动站监测和人工监测的营养盐在年际变化上呈现较一致的趋势,说明运用水质自动站监测该海域的营养盐变化趋势较为准确。 相似文献
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Fabio Ricci Nunzio Penna Samuela Capellacci Antonella Penna 《Chemistry and Ecology》2014,30(4):364-375
In the northern Adriatic Sea, Mediterranean Sea, the mucilage phenomenon is usually related to the aggregation of extracellular organic matter of phytoplanktonic origin under special seasonal and trophic conditions. Environmental factors, such as temperature, salinity, nitrogen, phosphorus and N/P ratio as well as polysaccharide and monosaccharide levels in the presence and absence of mucilage were investigated in the northern Adriatic Sea. Variations in temperature and salinity during spring in years characterised by mucilage events have been recognised having an important role in preparing a favourable physical environment where mucilage formation could take place. Since the DIN/TP ratio increased markedly during the spring months (March–April) in 2002, 2003 and 2004, preceding the early summer mucilage outbreaks, it appeared that the DIN/TP ratio may be a more robust predictor than the DIN/DIP ratio, which, although more commonly used, exhibited a discontinuous trend. The contents of total carbohydrates, including monosaccharides and polysaccharides, in seawater also varied according to the presence or absence of mucilage, with an increase of polysaccharide levels during the late spring or early summer in the period of the mucilage appearance. The role of carbohydrates in the macro-aggregate formation was also investigated. 相似文献
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Spatial analysis for spring bloom and nutrient limitation in Xiangxi bay of three Gorges Reservoir 总被引:6,自引:0,他引:6
The spatial and temporal dynamics of physical variables, inorganic nutrients and phytoplankton chlorophyll a were investigated in Xiangxi Bay from 23 Feb. to 28 Apr. every six days, including one daily sampling site and one bidaily
sampling site. The concentrations of nutrient variables showed ranges of 0.02–3.20 mg/L for dissolved silicate (Si); 0.06–2.40
mg/L for DIN (NH4N + NO2N + NO3N); 0.03–0.56 mg/L for PO4P and 0.22–193.37 μg/L for chlorophyll a, respectively. The concentration of chlorophyll a and inorganic nutrients were interpolated using GIS techniques. The results indicated that the spring bloom was occurred
twice in space during the whole monitoring period (The first one: 26 Feb.–23 Mar.; the second one: 23 Mar.–28 Apr.). The concentration
of DIN was always high in the mouth of Xiangxi Bay, and PO4P was high in the upstream of Xiangxi Bay during the whole bloom period. Si seems no obvious difference in space in the beginning
of the spring bloom, but showed high heterogeneity in space and time with the development of spring bloom. By comparing the
interpolated maps of chlorophyll a and inorganic variables, obvious consumptions of Si and DIN were found when the bloom status was serious. However, no obvious
depletion of PO4P was found. Spatial regression analysis could explained most variation of Chl-a except at the begin of the first and second bloom. The result indicated that Si was the factor limiting Chl-a in space before achieved the max area of hypertrophic in the first and second bloom period. When Si was obviously exhausted,
DIN became the factor limiting the Chl-a in space.
Daily and bidaily monitoring of Site A and B, representing for high DIN: PO4P ratio and low DIN:PO4P ratio, indicated that the concentration of Si was decreased with times at both site A and B, and the dramatically drop of
DIN was found in the end monitoring at site B. Multiple stepwise regression analysis indicated that Si was the most important
factor affect the development of spring bloom both at site A and B in time series. 相似文献
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ABSTRACTTotal dissolved nitrogen (TDN), including dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON), is of significant importance in aquatic systems due to its roles in numerous environmental processes, such as nutrients for agriculture activities, sources for lake and estuary eutrophication, and one of the major factors contributing to disinfection byproduct formation. The distribution and impact of DIN on these processes are relatively well-understood; however, information on DON is extremely limited, as there is no direct method for its quantification. DON is conventionally determined by subtracting DIN from TDN. However, significant errors may be introduced if DIN is the predominant species in samples with high concentrations of TDN. In order to deal with this challenge, pretreatment method for nitrogen gas stripping was investigated using 56 water samples collected from various ecosystems. The results indicated that after nitrogen gas stripping pretreatment, removal % of ammonia nitrogen (NH3–N) was more than 87.5%, and the ratios of removal of NH3–N/removal of TDN (β) were over 86.5% for most of 56 samples with high [NH3–N], indicating a high efficiency for removal of NH3–N, and that NH3–N was the predominant nitrogen species removed for the samples with high [NH3–N]. Therefore, nitrogen gas stripping is an appropriate pretreatment method for DON testing when NH3–N is the dominant inorganic nitrogen species. 相似文献
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2000—2010年深圳湾及其邻近海域溶解无机氮的时空分布 总被引:2,自引:0,他引:2
依据2000—2010年每月一次的调查资料,简要描述和讨论了深圳湾及邻近水域中溶解无机氮(DIN)质量浓度的时空分布,并结合现场盐度(S)、氨氮(NH3-N)、亚硝酸盐氮(NO2-N)和硝酸盐氮(NO3-N)实测数据探讨DIN的组成和来源.结果表明,深圳湾和伶仃洋东部沿岸多年平均DIN质量浓度分别为(2.445±1.841) mg·L-1和(0.517±0.366) mg·L-1.在深圳湾,DIN质量浓度的年内变化特征为丰水期较低,枯水期较高.在伶仃洋东部沿岸,DIN质量浓度的年内变化呈明显的年周期循环特征,夏季达到最高而冬季最低.11 a研究期间,伶仃洋东部沿岸DIN质量浓度略呈上升趋势;深圳湾DIN质量浓度在2000—2004年呈上升趋势,2005—2010年则呈下降趋势.各形态DIN质量分数的大小顺序从深圳湾内的NH3-N>NO3-N>NO2-N转变至湾外的 NO3-N>NH3-N>NO2-N.DIN 与 S 之间存在着显著的负相关,依二元混合质量平衡模式估算的伶仃洋东部沿岸 DIN的陆源质量分数约为77.9%,而深圳湾的都>92%. 相似文献
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太湖不同湖区无机氮转化潜力 总被引:4,自引:0,他引:4
采集太湖梅梁湾和东太湖的水样和积物,在实验室内模拟研究不同湖区水体中溶解性无机氮(DIN)短期内的转化潜力.研究结果表明,太湖藻型湖区(梅梁湾)和草型湖区(东太湖)水体中存在着强烈的硝化作用,NH 4-N和NO3-N含量之间表现出显著的负相关关系(P<0.05或P<0.01),NH 4-N质量浓度下降速率为0.08~0.19 mg·L-1·d-1.在同样的试验条件下,藻型湖区硝化速率高于草型湖区.NH 4-N初始浓度越高则硝化速率也越高,不添加外源氮时硝化速率随着时间的推移而逐渐降低.藻型湖区的反硝化作用强于草型湖区.室内模拟试验20 d后,沉积物中TN含量平均下降了3.7%,东太湖水样中平均下降26.7%,梅梁湾平均下降42.2%.湖泊沉积物是进行反硝化作用的重要场所.短期内DIN的转化潜力反映了不同湖区氮素转化速率,也反映了不同生态类型水体对湖泊氮素转化的影响. 相似文献