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1.
滇池是中国最大的高原淡水湖泊,是长江上游生态安全格局的重要组成部分。自2008年起政府在滇池湖滨带大规模退耕还草还林,以恢复滇池及其湖滨生态。湖滨带植被对滇池总磷浓度的影响是一个长期过程,需要通过遥感长时间连续监测的数据来评价。本文以滇池和滇池湖滨带为研究区,从空间分布、季节差异2个角度,结合入湖河流总磷负荷,研究2005—2018年滇池湖滨植被时空变化对滇池总磷浓度的影响。主要结论如下：① 滇池总磷浓度由湖缘向湖心逐渐降低,并且北部和南部偏高;2005—2018年,滇池总磷浓度呈现显著下降趋势;② 2011—2018年滇池总磷浓度显著减小与湖滨带植被的拦截作用密切相关;③ 2005—2018年滇池湖滨带草本和木本植物面积都显著增加,增加最剧烈的年份是2010—2011年;④ 相比于平水期和丰水期,枯水期NDVI与强影响区总磷浓度负相关关系最强,且木本植物NDVI与强影响区总磷浓度负相关性强于草本。本文利用长时间序列数据评价滇池总磷浓度与其湖滨植被的响应关系,可为滇池湖泊生态恢复提供科学依据。  相似文献   

2.
Stormwater runoff in rural townships has a high potential for water quality impairment but little information is available on strormwater runoff pollution from rural townships.To investigate the characteristics of runoff pollution in a rural township,a catchment(2.32 ha) in Linshan Township,Sichuan,China was selected to examine runoff and quality parameters including precipitation,flow rate,and total nitrogen(TN),dissolved nitrogen(DN),total phosphorus(TP),dissolved phosphorus(DP),particulate phosphorus(PP),chemical oxygen demand(COD) and suspended solid(SS) in 12 rainfall events occurring between June 2006 and July 2007.Results show that the annual pollutant loads were 47.17 kg ha-1 for TN,6.64 kg ha-1 for TP,1186 kg ha-1 for COD,and 4297 kg ha-1 for SS.DN and PP were the main forms of nitrogen and phosphorus in stormwater runoff.TP,COD and SS showed medium mass first flushes,in which nearly 40% of the total pollutant masses were transported by the first 30% of total flow volume.The peak of pollutant concentration appeared before the peak of runoff due to the first flush of accumulative pollutants in impervious areas and drainage ditches.The EMC values of TN,TP,DN and PP were negatively correlated to the maximum rainfall intensity,precipitation,total flow volume,and runoff duration(P<0.05,n=12),while EMC of COD and SS were not related to any rainfall characteristics.The FF30(FF,First Flush) for TN,TP,COD and SS were positively correlated to the maximum rainfall intensity(P<0.05,n=12),and TP was also positively correlated to the average rainfall intensity(P<0.05,n=12),indicating that the magnitude of first flush increased with the rainfall intensity in the Linshan Township.  相似文献   

3.
Sediment samples were cored from 3 locations representing the inner bay, the outer bay and the bay mouth of Jiaozhou Bay in September 2003 to study the source and biogeochemical characteristics of nitrogen and phosphorus in the bay. The content and vertical distributions of total nitrogen （TN）, total phosphorus （TP）, organic nitrogen （ON）, organic phosphorus （OP）, inorganic nitrogen （IN）, inorganic phosphorus （IP）, the ratio of organic carbon and total nitrogen （OC/TN）, and the ratio of total nitrogen and total phosphorus （TN/TP） in the sediments were analyzed. The results show that both TN and TP in surface sediments decrease from the inner bay to the outer bay. In general, ON occupies 50%-70% of TN and IP accounts for more than 60% of TP. In ratio of OC：TN, the nitrogen accumulated in the sediments from the inner bay and the bay mouth came mainly from terrestrial sources, and the portion of autogenetic nitrogen was 28.9% and 13.1%, respectively. However, in the outer bay, nitrogen was mainly autogenetic, accounting for 62.1% of TN, whereas phosphorus was mainly land-derived. The sedimentation fluxes of nitrogen and phosphorus varied spatially. The overall diagenesis rate of nitrogen was higher than that of phosphorus. Specifically, the diagenesis rate of OP was higher than that of IP. However, the diagenesis rate of ON was not always higher than that of IN. In species, the diagenesis rate of IN is sometimes much higher than that of the OC. In various environments, the diagenesis rate is, to some degree, affected by OC, pH, Eh, and Es.  相似文献   

4.
The multi-level ditch system developed in the Sanjiang Plain, Northeast China has sped up water drainage process hence transferred more pollutants from farmlands into the rivers of this region. Understanding the seasonal dynamics of nitrogen (N) and phosphorus (P) transportation in the ditch system and the role of different ditch size is thus crucial for water pollution control of the rivers in the Sanjiang Plain. In this study, an investigation was conducted in the Nongjiang watershed of the Sanjiang Plain to study the nutrient variation and the correlation between water and sediments in the ditch system in terms of ditch level. Water and sediments samples were collected in each ditch level in growing season at regular intervals (once per month), and TN, NO3 −N, NH4 +-N, TP, and PO4 3−-P were analyzed. The results show that nutrient contents in water were higher in June and July, especially in July, the contents of TN and TP were 3.21 mg/L and 0.84 mg/L in field ditch, 4.04 mg/L and 1.06 mg/L in lateral ditch, 2.46 mg/L and 0.70 mg/L in branch ditch, 1.92 mg/L and 0.63 mg/L in main ditch, respectively. In August and September, the nutrient contents in the water were relatively lower. The peak value of nutrient in ditch water had been moving from the field ditch to the main ditch over time, showing a remarkable impact of ditch system on river water environment. The nutrient transfer in ditch sediments could only be found in rainfall season. Nutrient contents in ditch sediment had effect on that in ditch water, but nutrients in ditch water and sediments had different origination. Ditch management in terms of the key factors is hence very important for protecting river water environment.  相似文献   

5.
Soil carbon and nutrient contents and their importance in advancing our understanding of biogeochemical cycling in terrestrial ecosystem, has motivated ecologists to find their spatial patterns in various geographical area. Few studies have focused on changes in the physical and chemical properties of soils at high altitudes. Our aim was to identify the spatial distribution of soil physical and chemical properties in cold and arid climatic region. We also tried to explore relationship between soil organic carbon (SOC) and total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP), soil particle size distribution (PSD). Samples were collected at 44 sites along a 300 km transect across the alpine grassland of northern Tibet. The study results showed that grassland type was the main factor influencing SOC, TN and TP distribution along the Gangdise Mountain-Shenzha-Shuanghu Transect. SOC, TN and TP contents were significantly higher in alpine meadow than alpine steppe ecosystems. SOC, TN, TP and AN contents in two soil layers (0-15 cm and 15-30 cm) showed no significant differences, while AP content in top soil (0-15 cm) was significantly higher than that in sub-top soil (15-30 cm). SOC content was correlated positively with TN and TP content (r = 0.901 and 0.510, respectively). No correlations were detected for clay content and fractal dimension of particle size distribution (D). Our study results indicated the effects of vegetation on soil C, N and P seem to be more important than that of rocks itself along latitude gradient on the northern Tibetan Plateau. However, we did not found similar impacts of vegetation on soil properties in depth. Inaddition, this study also provided an interesting contribution to the global data pool on soil carbon stocks.  相似文献   

6.
Hydrological and hydro-chemical monitoring of nitrogen (N) and phosphorus (P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin, China, from 2010 through 2011. The diffuse N and P loadings in different forms of total nitrogen (TN) and phosphorus (TP), dissolved nitrogen (DN) and phosphorus (DP), as well as particulate nitrogen (PN) and phosphorus (PP) were calculated based on runoff discharges and chemical analyses. The results revealed that the diffuse pollution concentrations of TN, DN, PN, TP, DP and PP exhibited large variations during rainfall events, with peak concentrations occurring during the initial period. For all of the measured parameters, the event mean concentrations (EMCs) were observed to clearly vary among rainfall events. The EMCs of TN, DN, PN, TP, DP and PP (for all of the observed rainfall events) were 10.04, 6.62, 3.42, 1.30, 0.47 and 0.83 mg/L, respectively. The losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September, when the losses totaled 99.3 and 9.6 kg/ha for TN and TP, respectively, accounting for 75% and 74% of the total annual loadings. The mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha, respectively. The results indicate that residential areas in the hilly area of the central Sichuan Basin are subject to high diffuse N and P loadings, posing a serious risk to the receiving water quality. Ecological buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.  相似文献   

7.
Estimating carbon sequestration and nutrient accumulation rates in Northeast China are important to assess wetlands function as carbon sink buffering greenhouse gas increasing in North Asia. The objectives of this study were to estimate accreting rates of carbon and nutrients in typical temperate wetlands. Results indicated that average soil organic carbon(SOC), total nitrogen(TN) and total phosphorus(TP) contents were 37.81%, 1.59% and 0.08% in peatlands, 5.33%, 0.25% and 0.05% in marshes, 2.92%, 0.27% and 0.10% in marshy meadows, respectively. Chronologies reconstructed by 210 Pb in the present work were acceptable and reliable, and the average time to yield 0–40 cm depth sediment cores was 150 years. Average carbon sequestration rate(Carbonsq), nitrogen and phosphorus accumulation rates were 219.4 g C/(m~2·yr), 9.16 g N/(m~2·yr) and 0.46 g P/(m~2·yr) for peatland; 57.13 g C/(m~2·yr), 5.42 g N/(m~2·yr) and 2.16 g P/(m~2·yr) for marshy meadow; 78.35 g C/(m~2·yr), 8.70 g N/(m~2·yr) and 0.71 g P/(m2·yr) for marshy; respectively. Positive relations existed between Carbonsq with nitrogen and precipitations, indicating that Carbonsq might be strengthened in future climate scenarios.  相似文献   

8.
To investigate the spatio-temporal and compositional variation of selected water quality parameters and understand the purifying effects of wetland in Fujin National Wetland Park(FNWP), China, the trophic level index(TLI), paired samples t-test and correlation analysis were used for the statistical analysis of a set of 10 water quality parameters. The analyses were based on water samples collected from 22 stations in FNWP between 2014 and 2016. Results initially reveal that total nitrogen(TN) concentrations are above class V levels(2 mg/L), total phosphorus(TP) concentrations are below class Ⅲ levels(0.2 mg/L), and that all other parameters fall within standard ranges. Highest values for TN, pH, and Chlorophyll-a were recorded in 2016, while the levels of chemical oxygen demand(COD_(Mn)) and biochemical oxygen demand(BOD5) were lowest during this year. Similarly, TN values were highest between 2014 and 2016 while dissolved oxygen(DO) concentrations were lowest in the summer and TP concentrations were highest in the autumn. Significant variations were also found in Secchi depth(SD), TN, CODMn(P 0.01), TP, and DO levels(P 0.05) between the inlet and outlet of the park. High-to-low levels of TN, TP, and TDS were found in cattails, reeds, and open water(the opposite trend was seen in SD levels). Tested wetland water had a light eutrophication status in most cases and TN and TP removal rates were between 7.54%–84.36% and 37.50%–70.83%, respectively. Data also show no significant annual changes in water quality within this wetland, although obvious affects from surrounding agricultural drainage were nevertheless recorded. Results reveal a high major nutrient removal efficiency(N and P). The upper limits of these phenomena should be addressed in future research alongside a more efficient and scientific agricultural layout for the regions in and around the FNWP.  相似文献   

9.
To improve the burial flux calculations of bioavailable phosphorus(P) and study opal-associated P(Opal-P) in the East China Sea(ECS), surface and core sediments were collected in the Changjiang Estuary(CE) and the south of the Cheju Island. In this study, sedimentary P was operationally divided into seven different forms using modified sedimentary extraction(SEDEX) technique: LSor-P(exchangeable or loosely sorbed P), Fe-P(easily reducible or reactive ferric Fe-bound P), CFA-P(authigenic carbonate fluorapatite and biogenic apatite and CaCO_3-bound P), Detr-P(detrital apatite), Org-P(organic P), Opal-P and Ref-P(refractory P). The data revealed that the concentrations of the seven different P forms rank as Detr-P CFA-P Org-P Ref-P Opal-P Fe-P LSor-P in surface sediments and CFA-P Detr-P Org-P Ref-P Fe-P Opal-P LSor-P in core sediments. The distributions of the total phosphorus(TP), TIP, CFA-P, Detr-P are similar and decrease from the CE to the south of the Cheju Island. Meanwhile, Org-P and Opal-P exhibit different distribution trends; this may be affected by the grain size and TOM. The concentrations of potentially bioavailable P are 9.6-13.0 μmol g~(-1) and 10.0-13.6 μmol g~(-1), representing 61%-70% and 41%-64% of the TP in surface and core sediments, respectively. The concentrations of Opal-P are 0.6-2.3 μmol g~(-1) and 0.6-1.4 μmol g~(-1) in surface and core sediments, accounting for 5.3%-19.8% and 4.2%-10.6% of bioavailable P, respectively. The total burial fluxes of Opal-P and bioavailable P are 1.4×10~9 mol yr~(-1) and 1.1×10~10 mol yr~(-1) in the ECS, respectively. Opal-P represents about 12.7% of potentially bioavailable P, which should be recognized when studying P cycling in marine ecosystems.  相似文献   

10.
To understand the responses of a freshwater ecosystem to the impoundment of the Three Gorges Reservoir (TGR), phytoplankton was monitored in the tributaries of the TGR area. From August 2010 to July 2011, algal species composition, abundance, chlorophyll a and other environmental parameters were investigated in the Gaolan River, which is a tributary of Xiangxi River. Thirty-one algal genera from seven phyla were identified. Results show that the lowest concentrations of total phosphorus (TP) and total nitrogen (TN) were 0.06 mg/L and 1.08 mg/L, respectively. The values of TP and TN exceeded the threshold concentration of the eutrophic state suggested for freshwater bodies. In the Gaolan River, the succession of phytoplankton showed clear seasonal characteristics. Different dominant species were observed among seasons under the control of environment factors. In spring and summer, the dominant species were Nitzschia sp. and Aphanizomenon flos-aquae (L.) Ralfs, the limiting nutrient was NO 3 ? -N, and the key environmental factor for phytoplankton population succession was water temperature (WT). In autumn and winter, the dominant species were A. flos-aquae and Chlorella sp., the limiting nutrient was PO 4 3? -P, and the key environmental factors were transparency and WT. This study illustrates the influence of physical and chemical factors on phytoplankton seasonal succession in a tributary of TGR since the downstream regions of Xiangxi River and Gaolan River became reservoirs after impoundment of the Three Gorges Dam. We suggest that this activity has significantly affected water quality in the dam area.  相似文献   

11.
滇池污染的成因及其治理新方案   总被引：9，自引：0，他引：9  
本文对滇池的污染成因进行了综合分析。滇池污染是由两大因素造成的:一是水流太慢,二是污水南侵。从这两大污染因素可以找到两大对策:一是加速湖水流动,二是阻止污水南侵。基于滇池污染实际上是北部污染南部造成的,改变滇池出水口,开挖一条新河道,让滇池水倒流,滇池从原来的下游方换到上游方,城区污水不入滇池,即使进入也能让它快速从北部流出去,北部的污染负荷很容易从北部流出去,南部高水位的水位势压力阻止了北部负荷南侵,解决了滇池污染。  相似文献   

12.
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13.
ＤＹＮＡＭＩＣ　ＶＡＲＩＡＴＩＯＮＳ　ＯＦ　ＷＡＴＥＲ　ＱＵＡＬＩＴＹ　ＩＮ　ＴＡＩＨＵ　ＬＡＫＥ　ＡＮＤ　ＭＵＬＴＩＶＡＲＩＡＴＥ　ＡＮＡＬＹＳＩＳ　ＯＦ　ＩＴＳ　ＩＮＦＬＵＥＮＴＩＡＬ　ＦＡＣＴＯＲＳＤＹＮＡＭＩＣＶＡＲＩＡＴＩＯＮＳＯＦＷＡＴＥ...  相似文献   

14.
In order to approach the characteristics of nitrogen and phosphorus pollution caused by cage culture and the balance of nitrogen and phosphorus during the process of cage culture, a monitoring was conducted in Daya Bay of Guangdong Province, China from April 2002 to Jane 2003. The results show that the concentrations of total nitrogen (TN) in the waters at the sites with five and ten years of cage culture history are 1.8 and 2.3 times of that at control site respectively. Ammonium (NH3-N) is the main form of nitrogen in spring while nitrate ( NO3 -) in winter. The concentrations of TN, total dissolved nitrogen (TDN) and dissolved organic nitrogen (DON) are highest in autumn. The concentration of phosphorus increases with the increasing of the culturing time, among which phosphate ( PO 34-) increases most obviously. The concentrations of total phosphorus (TP) and total dissolved phosphorus (TDP) are highest in autumn. The nitrogen and phosphorus are accumulated significantly in the sediment of cage culture area. The model of N balance in the cage culture area: bait (70.62%) fry (0.28%) input by tide (14.8%) release from sediment (14.3%) = harvest of adult fish (12.07%) deposition into sediment (28.75%) output by tide (56.18%) others (3.00%). The model of P balance: bait (83.11%) fry (0.17%) input by tide (12.23%) release from sediment (4.49%) = harvest of adult fish (8.43%) deposition into sediment (48.59%) output by tide (41.94%) others (1.04%). In one fish growth year, the contents of nitrogen and phosphorus in harvest of adult fish are only 17.0% and 10.1% of the contents of nitrogen and phosphorus in fish bait and fry, wherein 83% of nitrogen and more than 89% of phosphorus in fish bait became marine pollutants.  相似文献   

15.
To evaluate the influence of wetland reclamation on vertical distribution of carbon and nitrogen in coastal wetland soils, we measured the soil organic carbon(SOC), soil total nitrogen(STN) and selected soil properties at five sampling plots(reed marsh, paddy field, corn field, forest land and oil-polluted wetland) in the Liaohe River estuary in September 2013. The results showed that reclamation significantly changed the contents of SOC and STN in the Liaohe River estuary(P 0.001). The SOC concentrations were in the order: oil-polluted wetland corn field paddy field forest land reed marsh, with mean values of 52.17, 13.14, 11.46, 6.44 and 6.16 g/kg, respectively. STN followed a similar order as SOC, with mean values of 1351.14, 741.04, 632.32, 496.17 and 390.90 mg/kg, respectively. Interaction of reclamation types and soil depth had significant effects on SOC and STN, while soil depth had significant effects on SOC, but not on STN. The contents of SOC and STN were negatively correlated with pH and redox potential(Eh) in reed marsh and corn field, while the SOC and STN in paddy field had positive correlations with electrical conductivity(EC). Dissolved organic carbon(DOC), ammonium nitrogen(NH_4~+-N) and nitrate nitrogen(NO_3~–-N) were also significantly changed by human activities. NH_4~+-N and NO_3~–-N increased to different degrees, and forest land had the highest NO_3~–-N concentration and lowest DOC concentration, which could have been caused by differences in soil aeration and fertilization. Overall, the results indicate that reed harvest increased soil carbon and nitrogen release in the Liaohe River Estuary, while oil pollution significantly increased the SOC and STN; however, these cannot be used as indicators of soil fertility and quality because of the serious oil pollution.  相似文献   

16.
Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrogen(TN) and total phosphorus(TP) were determined to analyze the chronology and nutrients change in recent sediment.The results show that 137Cs activities are low(less than 15 Bq/kg) in the two cores,attributed to the 137Cs migration.Based on 210Pb constant rate of supply(CRS) model,the sedimentation accumulation rates range from 0.13 g/(cm2·yr) to 0.76 g/(cm2·yr) in the ZS core,and from 0.10 g/(cm2·yr) to 0.56 g/(cm2·yr) in the THS core.A remarkable increase in organic matter and nutrients has occurred in the two dated cores since the mid-1980s.The historical changes of organic matter and nutrients in the two cores are consisitent with the monitoring data for surface sediment after the 1960s.The TP accumulation rates after the early 1980s are 0.97 and 0.92 times higher than those from the 1950s to the 1980s in ZS and THS cores,respectively.Higher TP concentrations in the past two-decade deposits of Taihu Lake are due to both diagenetic factors and human activities.  相似文献   

17.
Whether it is necessary to reduce nitrogen(N) and/or phosphorus(P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that support the contrasting ideas. To test the response of phytoplankton to various combinations of nutrient control strategies in mesocosms and the possibility of reflecting the conditions in natural ecosystems with short-term experiments, a 9-month experiment was carried out in eight 800-L tanks with four nutrient level combinations(+N+P,-N+P, +N-P, and-N-P), with an 18-month whole-ecosystem experiment in eight ~800-m~2 ponds as the reference. Phytoplankton abundance was determined by P not N, regardless of the initial TN/TP level, which was in contrast to the nutrient limitation predicted by the N/P theory. Net natural N inputs were calculated to be 4.9, 6.8, 1.5, and 3.0 g in treatments +N+P,-N+P, +N-P, and-N-P, respectively, suggesting that N deficiency and P addition may promote natural N inputs to support phytoplankton development. However, the compensation process was slow, as suggested by an observed increase in TN after 3 weeks in-N+P and 2 months in-N-P in the tank experiment, and after 3 months in-N?+P and ~3 months in-N-P in our pond experiment. Obviously, such a slow process cannot be simulated in short-term experiments. The natural N inputs cannot be explained by planktonic N-fixation because N-fixing cyanobacteria were scarce, which was probably because there was a limited pool of species in the tanks. Therefore, based on our results we argue that extrapolating short-term, small-scale experiments to large natural ecosystems does not give reliable, accurate results.  相似文献   

18.
Based on the observed data in monitored drainage areas and GIS spatial analysis tools, watershed basic database of Shitoukoumen Reservoir Basin was built. The multivariate analysis and redundancy analysis (RDA) were used to analyze the spatial and temporal variations of water quality, identify the key environmental factors and their patterns influencing the spatial variation of water quality, and determine the main types and forms of the non-point source (NPS) pollutant export controlled by the key environmental factors. The results show that different patterns of environmental factors lead to great changes in water quality at spatial and seasonal scales. All selected environmental factors explain 64.5% and 68.2% of the spatial variation of water quality over dry season and rainy season, respectively, which shows clear seasonal difference. Over dry season, residential land is the most important environmental factor, which possesses 35.4% of the spatial variation, and drainage area is the second key environmental factor, which possesses 17.0% of spatial variation in the total variance. Over rainy season, slope length and drainage area are the key environmental factors, which possess 29.3% of the spatial variation together. Residential land influences nitrogen export by changing NH4 +-N and particulate organic nitrogen (PON) discharge over dry season, and drainage area controls phosphorus export by regulating dissolved phosphorus (DP) drainage over dry season and phosphorus associated particulate (PAP) loss over rainy season, respectively. Although slope length is an important environmental factor, it does not influence NPS pollutant export. It is interesting that soil organic matter, as a minor environmental factor, highly determines phosphorus and nitrogen export by enhancing the DP, PAP and PON loss.  相似文献   

19.
A 6.2 m thick core of Gucheng Lake sediment provided a 3600 years record of climate change. The contents of the TOC in the core changed from 2.63% to 8.48%, and the δ13C values of organic matter were from −21.54% to −27.3%. The TOC/TN ratios indicated that the organic materials in sediments were from lake plankton and land-derived plants. The 2.9–22 m core interval with high TOC/TN ratios, low δ13C values and low contents of TOC indicated a cold climate stage. The 6.2–5.5 m and 0.4–0.1 m intervals were characterized by low TOC/TN ratios, high δ13C values and high contents of TOC, and reflected temperate climate stages. Project 49372129 supported by NSFC.  相似文献   

20.
1 INTRODUCTION δ13C in organic matters from lacustrine sedi- ments varies with several factors including aquatic plants, vegetation type in the catchment, atmos- pheric CO2 concentration, climate (temperature and precipitation), and properties of water, …  相似文献   

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