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1.
Spatial regression models were used to predict yields (kg?ha?1?yr?1) of nitrogen (N) and phosphorus (P) discharged from catchments throughout New Zealand under natural and current conditions. The models were derived using loads (kg?yr?1) of TN, NO3-N, TP and DRP calculated for 592 river water quality monitoring sites. Anthropogenic increases in yields above natural levels were associated with the proportions of catchments occupied by the intensive agricultural land cover and were unevenly distributed across regions. Anthropogenic increases in national loads of TN, NO3-N, TP and DRP exported to the ocean were 74%, 159%, 48% and 18%, respectively. Increases in loads exported to the ocean varied considerably at smaller scales, with catchments having significant load increases between 4- and 26-fold for N and 6- to 9-fold for P. Predictions of yields and loads reported here have utility in the development of strategies to manage nutrients. 相似文献
2.
Robert J. Wilcock John W. Nagels Harvey J. E. Rodda Michael B. O'Connor Bruce S. Thorrold James W. Barnett 《新西兰海洋与淡水研究杂志》2013,47(4):683-696
A small stream in a predominantly dairying catchment in the Waikato region of New Zealand was monitored for 2 years at three sites. Total nitrogen (TN) concentrations were up to 7.09 g m‐3 in winter, with the bulk comprising nitrate nitrogen (NO‐ 3‐N). During summer NO‐ 3‐N was near zero and TN mostly comprised organic nitrogen. Maximum concentrations of total phosphorus (TP) and dissolved reactive phosphorus (DRP) were 1.64 and 0.555 g m‐3, respectively, and peaks coincided with spring and autumn applications of phosphorus fertiliser. Ammoniacal nitrogen concentrations exceeded 1 g m‐3 on several occasions and mean concentrations at the three sites were 0.165–0.272 g m‐3. Faecal coliform and enterococci bacteria concentrations were 64–26000 and 7–23000 cfu per 100 ml, respectively. Specific yields of TN and NO‐ 3‐N (35.3 and 30.7 kg ha yr‐1, respectively) were much greater than any previously reported for New Zealand pasture catchments, whereas TP and DRP yields (1.16 and 0.54 kg ha yr‐1, respectively) were more in accord with other studies. Greater use of land treatment of liquid wastes will reduce stream inputs of faecal organisms, NH4‐N and P. 相似文献
3.
R. A. Hoare 《新西兰海洋与淡水研究杂志》2013,47(4):451-454
Nitrate concentrations in urban streams at Rotorua are much higher than those in nearby rural streams. The loads of nitrogen are consistent with the loads discharged to septic tanks in the stream catchments. Phosphorus concentrations are no higher than in rural streams, and phosphorus loads in the streams are less than 2% of the load on the septic tanks. Nitrate in the streams is slowly decreasing now that the sewerage reticulation system is almost complete. 相似文献
4.
The Zhelin Bay is one of the most important bays for large-scale mariculture in Guangdong Province, China. Owing to the increasing human population and the expanding mariculture in the last two decades, the ecological environment has greatly changed with frequent harmful algal blooms. A monthly survey of water content, organic matter （TOM）, and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted. The results showed that the water content was correlated significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys. TOM was also correlated significantly with various forms of nitrogen and phosphorus, indicating that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters. Average total Kjeldhal nitrogen （TkN） content was（ 1 113.1 ± 382.5）μg/g and average total phosphorus （TP） content was（567.2± 223.3）μg/g, and both were much higher than those of similar estuaries in China and elsewhere. Average nitrogen and phosphorus tended to be higher inside than outside the bay, higher at aquaculture than non-aquaculture areas, and higher at fish-cage culture than oyster culture areas, suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay. Various forms of nitrogen and phosphorus concentrations were higher during the warm season （July--September）, which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species. Compared with July 2002, TkN and TP contents were much higher in July 2003, in consonance with the eutrophication of the Zhelin Bay. Because exchangeable phosphorus （Ex-P）, iron-bounded phos- phorus （Fe-P） and organic phosphorus （OP） combined accounted for 34.3% of the TP and authigenic phosphorus （Au-P 相似文献
5.
ABSTRACT Dissolved nutrient uptake and metabolism by periphyton in a central North Island gravel-bed river were investigated using recirculating in-situ chambers. Dissolved inorganic nitrogen (DIN) uptake was correlated with photosynthesis and chlorophyll but N uptake and carbon fixation were partly de-coupled indicating storage. Dissolved reactive phosphorus (DRP) uptake was only weakly correlated with photosynthesis. Diatoms and green algae relied on DRP in the water, but Cyanobacteria met part of their P needs from storage. Dissolved organic nutrients were excreted in both light and dark incubations, with approximately 50% of DIN uptake during photosynthesis excreted as DON. To simulate diurnal variations in nutrients, oxygen and pH existing computer models need to de-couple photosynthesis from nutrient uptake, allow for variable stoichiometry and better quantify recycling of organic nutrients. 相似文献
6.
Environmental impact factors and mercury speciation in the sediment along Fujian and eastern Guangdong coasts 总被引：1，自引：0，他引：1
ZHANG Yuanbiao HUO Yunlong LIU Xiyao KUANG Weiming YUAN Dongxing JI Weidong 《海洋学报(英文版)》2013,32(2):76-80
Concentrations of total mercury (THg) and methyl mercury (MeHg) were determined for 32 surface sediments collected along the coastal line of Fujian Province and eastern Guangdong Province. The spatial distributions of THg and MeHg and their environmental impact factors were investigated. The average concentrations of THg and MeHg in the sediments were 31.5 ng/g and 0.096 ng/g, respectively. Both sediment THg and MeHg concentrations showed relatively high value in the Minjiang Estuary and the coastal areas of Quanzhou and Putian. The concentrations overall decreased as the distance to the shoreline increased. The correlations among environmental impact factors and THg, MeHg were analyzed. The sediment THg concentration was highly correlated to the concentrations of organic matter, copper, total nitrogen (TN) and total phosphorus (TP), and significantly correlated to pH value of the bottom seawater and concentration of sediment sulfide. The sediment MeHg concentration was highly correlated to the concentrations of organic matter and copper, and significant correlated to the concentrations of sulfide, TN, TP and pH value of the bottom seawater. 相似文献
7.
The chemical quality of the Waiohewa stream, Rotorua, was assessed from the results of 2 longitudinal surveys in summer 1978–79. In particular, changes in nitrogen concentration were examined. The quantity of ammonia increased downstream from unmonitored geothermal inputs, but, after dilution and neutralisation by a larger inflow of freshwater, considerable proportions of ammonia were converted to nitrate. In the first survey ammonia concentrations decreased from 4.48 to 2.47 g m‐3 and nitrate concentrations increased from 0.59 to 1.13 g ‐3 in a 3‐km stretch of the stream. Mass flow calculations show that nitrification could account for at least 55% of the ammonia decrease, the rest probably being lost through assimilation or denitrification. Laboratory incubation experiments showed that nitrification occurred in the stream bed. The geothermal waters contained low concentrations of boron (1.1–4.0 g m‐3), filterable mercury (0.1–0.8 mg m‐3) and arsenic (10–14 mg m‐3). 相似文献
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9.
David Roper 《新西兰海洋与淡水研究杂志》2013,47(4):487-498
Abstract Benthos near a sewage outfall discharging 69 000 m3 d?1 of municipal sewage into Tauranga Harbour was studied to determine the nature and extent of the impact caused by a small organic input. Sediment samples were collected about the outfall and analysed for particle size, sorting, mud content, readily oxidisable carbon (ROC), total Kjeldahl nitrogen (TKN), total phosphorus (TP), “oil and grease” (OG), and macroinvertebrates. It is concluded that observed patterns of physical sediment characteristics are mainly natural. Levels of ROC, TKN, TP, and OG were all highest at or nearby the outfall. However, chemical changes in the sediment related to the discharge seemed to be limited to within less than 50 m distance of the outfall. The distributions of ROC, TKN, and TP in the sediments were closely related to natural changes in mud content. The outfall had little effect on the distribution of total numbers of taxa or individuals, or the composition of macro‐invertebrate assemblages. Rather, these were most closely related to the (probably natural) variability in sediment particle size and sorting. Analysis of the distributions of common species showed that several were responding to the discharge, but such responses were limited to within 10 m of the outfall. Trie absence of extensive impact on benthos from the outfall probably related to high water velocities (up to 0.5 m sr?1 on a mean tide) over the outfall diffuser, which would ensure that any drop in sediment oxygen levels is small. 相似文献
10.
Dae-In Lee Jeong-Min Choi Yeon-Gyu Lee Moon-Ock Lee Won-Chan Lee Jong-Kyu Kim 《Estuarine, Coastal and Shelf Science》2008,80(4):495-508
An eco-hydrodynamic model was used to estimate the carrying capacity of pollutant loads and response of water quality to environmental change in Yeoja Bay, Korea. An energy-system model also was used to simulate the fluctuation in nutrients and organic matter in the bordering wetland. Most water quality factors showed a pulsed pattern, and the concentrations of nutrients and organic matter of seawater increased when input loads of nutrients increased due to freshwater discharge. The well-developed tidal zones and wetlands in the northern area of the bay were highly sensitive to input loads. Residence times of water, chemical oxygen demand (COD), and dissolved inorganic nitrogen (DIN) within the bay were estimated to be about 16 days, 43.2 days, and 50.2 days, respectively. Water quality reacted more sensitively to the effects of nitrogen and phosphorus input than to COD. A plan to reduce the present levels of COD and dissolved inorganic phosphorus (DIP) by 20–30% and DIN by at least 50% in pollutant loads is needed for satisfying the target water quality criteria. The natural removal rate of nutrients in wetlands by reeds was assessed to be approximately 10%. 相似文献
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12.
2008年春季对莱州湾小清河口的走航调查发现,调查区域大部分水体的DOC,CODMn,NH4+-N,PO43--P高于4类海水的限定值,处于严重污染状态。水体CHla的浓度范围在1.02~37.92μg/L之间,但DO饱和度却在23%~96%之间,盐度小于15水体的DO饱和度低于50%,水体缺氧严重。河口存在NO2--N含量偏高现象。由河口向外,NO2--N浓度逐渐增加,至盐度24.4的水体达到0.27 mg/L的高值,NO2--N增加主要是NH4+-N的硝化反应产生的。NH4+-N生成NO2--N主要受DO和NH4+-N比例与浓度的影响,DO饱和度在30%~70%,NH4+-N大于3.33 mg/L的水体中NO2--N生成速率最快。 相似文献
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为获知不同时期封闭式海水循环水养殖系统中水质因子、浮游植物和细菌群落结构对大西洋鲑(Salmo salar)体内土腥味物质含量变化的影响,于2018—2019年4次采集封闭式海水循环水养殖系统的水样和大西洋鲑。测定水体的氨氮、亚硝氮、硝氮、活性磷酸盐等指标,分析水体浮游植物群落结构并通过16S高通量测序测定水体中细菌群落结构,通过微波蒸馏-固相微萃取-气相色谱-质谱联用(MD-SPME-GC-MS)方法,分析大西洋鲑背肌中土臭素(Geosmin,GSM)和二甲基异冰片(2-methylisoborneol,MIB)的含量。研究发现:测定水质指标中温度、溶解氧、盐度、pH、氨氮、亚硝氮、硝氮、活性磷酸盐、总氮、总磷、总悬浮物和溶解性总有机碳在不同时期差异显著。共鉴定出浮游植物7门、13目、26属,蓝藻门(Cyanophyta)、硅藻门(Bacillariophyta)和绿藻门(Chlorophyta)为优势门;不同时期细菌群落中的优势菌门均为变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes),但细菌群落结构存在差异,这主要是由水质差异引起的。在不同时期,鱼体MIB含量均高于GSM含量,MIB为鱼体中主要的土腥味物质,在7和10月MIB含量较高。鱼体土腥味物质含量受浮游植物和细菌群落影响,而水质因子可能通过影响浮游植物和细菌群落的结构,来影响养殖鱼体内土腥味物质的含量。 相似文献
15.
Measurements were made of suspended sediment (SS), volatile suspended solids, dissolved organic carbon (DOC), nitrogen (N) and phosphorus (P) concentrations, turbidity, black disk visibility, pH, alkalinity, and temperature, at monthly intervals for 2–5 years on nine streams draining catchments with pasture, pine plantation, and native forest land uses. Stream flow and flow‐weighted concentrations of SS, N, and P were also measured for up to 2 years from pasture, native forest, and mixed land‐use catchments enabling calculation of export (kg ha‐1 yr‐1). During 1996–97, export from the pasture stream was 2.5‐ to 7‐fold higher for SS (988), total P (1.50), total Kjeldahl N (5.65), nitrate N (4.37), and ammoniacal N (0.34) than from the stream draining native forest. In contrast, export of DOC (25.5) and dissolved reactive P (DRP) (0.25) from the pasture stream were within 20% of the native stream's values. Export of SS and nutrients (except DRP) from the pasture catchment was 4‐ to 15‐fold higher during the winters of 1995 and 1996 than winter 1997 when rainfall was half the normal level. Streams draining native forest had lower temperature, sediment, and nutrient concentrations (except DRP), and higher water clarity, than those draining pine forest and pasture. A pine/scrub stream had the highest SS and turbidity and lowest DRP, pH, and alkalinity. Pasture streams had the highest concentrations of all N species (geometric means 2‐to 4‐fold > native), total P, and DOC, and also showed the greatest variation in water quality attributes in relation to season and flow. The influences of land use were attributable to differences in both source materials of sediment and nutrients available for transport and changes in rates of in‐stream processing. 相似文献
16.
益阳大通湖生态因子的灰关联分析 总被引：1，自引：1，他引：0
本文采用灰色系统关联度分析方法,以空间理论数学为基础,依规范性、偶对称性、整体性和接近性原则,计算并分析了益阳大通湖14个生态因子的关联度,关联序结果为:亚硝酸氮氮磷比氨氮总氮硝酸氮浮游动物叶绿素a透明度总磷水深水温浮游植物酸碱度溶解氧。益阳大通湖表现为总氮(包括亚硝酸氮、氨氮和硝酸氮)和氮磷比是优势影响因子。通过灰关联分析发现,大通湖水体水质良好,水体的总氮、氮磷比及总磷都适于浮游生物的生长繁殖,对增加渔产潜力有重要作用。 相似文献
17.
福建九龙江口秋茄红树林鹧鸪菜几种营养元素含量的季节变化 总被引：1，自引：0，他引：1
研究了福建九龙江口秋茄(Kandelia candel)红树林潮间带的红藻鹧鸪菜(Caloglossa leprieurii)的氮、磷、钾、钠、钙与镁6种营养元素含量的季节变化。氮、磷、钾与钠均以春季含量最高；钙与镁分别以秋季和冬季最高。氮与磷含量冬季最低，钾含量秋季最低；钠、钙、镁均以夏季含量最低，6种元素含量的季节变化模式不一致。营养元素含量的季节变化表明鹧鸪菜春季富集的营养物质较多，与春季有较高的生物量一致。营养元素含量的季节变化反映了鹧鸪菜的生长与环境因子的季节变化。鸥鸪菜的氮、磷含量高于土壤含量。并明显高于水体氮、磷含量，说明鹧鸪菜能强烈富集环境中的氮、磷，因此鸥鸪菜类的大型藻类的存在可能是红树林区赤潮极少发生的原因之一。 相似文献
18.
乳山湾外低氧海域沉积物中有机碳、氮、磷及其形态特征分析 总被引：3，自引：0，他引：3
根据2009年8月在乳山湾及其毗邻海域的综合调查,分析了该海域表层沉积物中有机碳、氮、磷含量及其组成形态的变化,初步探讨了影响底质理化参数变化的原因及对乳山湾外近岸底层低氧形成的影响.结果表明,乳山湾外近海为粉砂质岸滩,以细颗粒为主;底质中有机碳含量介于0.49％ ～0.93％,平均值为0.69％;总氮含量介于382～1020 mg/kg,平均值为671 mg/kg;可溶性总氮含量介于23.0 ～ 60.0 mg/kg,平均值为44.0mg/kg,其中可溶性有机氮和氨氮分别占可溶性总氮的58.8％和38.8％;总磷含量介于138～769 mg/kg,平均值为356 mg/kg,有机磷是占有绝对优势的磷形态(62.5％).研究区域沉积物中总氮和湾内相当,有机碳、总磷含量普遍低于乳山湾内,但均明显高于南黄海区域,且呈还原性状态.调查区域内沉积物中相对较高的有机碳、氮、磷可能是在潮流作用下乳山湾与外海的物质交换所致,其耗氧过程是导致底层溶解氧亏损的重要原因,值得进一步关注. 相似文献
19.
九龙江-河口表层水体营养盐含量的时空变化及潜在富营养化评价 总被引：1，自引：0，他引：1
分别于2012年9月、2013年1、6月,对九龙江两大支流北溪、西溪及河口区开展了3个航次的营养盐监测.研究结果表明,河口区表层水体溶解无机氮（DIN）、总磷（TP）和活性磷酸盐（PO4-P）质量浓度范围分别为0.13-17.35、0.14-1.00和0.00-0.38 mg/dm3,受上游输入和海水稀释作用,营养盐浓度由淡水端至海水端逐渐降低.北溪表层水体的DIN、TP和活性磷酸盐质量浓度范围分别为1.99-24.92、0.12-1.47和0.04-0.68 mg/dm3,受龙岩地区工农业生产及城市进程影响,由上游至下游逐渐降低.西溪表层水体的DIN、TP和活性磷酸盐质量浓度范围分别为2.74-20.61、0.14-0.92和0.02-0.37 mg/dm3,受上游农业生产和下游漳州地区人类活动影响,上下游的DIN质量浓度较高.此外,九龙江沿岸的人类活动可能影响了该地区水体中的溶解无机氮形态组成：北溪和西溪上游的NH4-N和NO3-N占比分别较高.水期分析表明,2013年1月的DIN浓度显著高于其他水期,而不同区域TP和活性磷酸盐的水期波动不尽相同.营养盐结构分析表明,九龙江总体处于磷限制状态,但在河口及北溪部分站位,CDIN/CPO4-P比值已达到适合浮游生物生长繁殖的水平.潜在富营养化程度评价表明,九龙江河口多数站位均处于N或P限制的富营养化级别,但由于N、P营养盐的绝对浓度较高,具有水华暴发的潜在风险. 相似文献
20.
长江口及邻近水域氮、磷的形态特征及分布研究 总被引：3，自引：0，他引：3
根据近几年大面调查的监测资料,对长江口及邻近水域氮、磷营养盐的形态组成、时空分布及氮磷比的变动规律及其影响因素进行了分析研究。结果表明,长江口及邻近水域中硝酸盐是水体无机氮存在的主要形态,其约占总无机氮的90%,无机氮含量河口高,向东南方向愈来愈低;从该水域总磷的形态组成来看,磷营养盐主要以溶解态和颗粒态共存的形式存在,TDP略高于TPP,无机磷的平面分布与无机氮十分相似,春季无机磷含量高于夏季;N/P值变动范围大和平均值较高是该水域的主要特征,N/P值与长江径流量的大小有关系,夏季N/P值比春季高,综合分析来看,磷营养盐和光照都有可能成为该水域浮游植物生长的重要限制因子。 相似文献