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71.
The nitrogen(N) and phosphorus(P) budget and the ecological efficiency of a polyculture system of sea cucumber(Apostichopus japonicus), jellyfish(Rhopilema esculenta) and shrimp(Fenneropenaeus chinensis) were studied in a cofferdam, 120.2 ha in size. The nutrients were supplied by spring tide inflow. In total, 139600 kg N yr-1 and 9730 kg P yr-1 input to the system; while 118900 kg N yr-1 and 2840 kg P yr-1 outflowed from the system concurrently, thus the outflow was 85.7%(N) and 29.2%(P) of inflow. The production of N and P was 889.5 kg yr-1 and 49.28 kg yr-1(sea cucumber) and 204 kg yr-1 and 18.03 kg yr-1(jellyfish and shrimp), respectively. The utilization rate of N and P by polycultured animals was 7.8‰ and 6.9‰, respectively, 21.9% and 38% higher than that of monocultured sea cucumber. Our results indicated that the polyculture system was an efficient culture system of animals and a remediation system of coastal environment as well; it scavenged 14.3% and 70.8% of N and P, respectively. Such an ecological efficiency may be improved further by increasing either the stocking density or the size of sea cucumber or both. 相似文献
72.
贵州省瓮福磷矿沉积环境及矿床成因探讨 总被引:1,自引:0,他引:1
瓮福磷矿沉积的有利场所是潮下海湾浅滩环境,而不是潮坪。海湾的大小又控制着矿床的规模,海滩能量的差异影响着磷矿石的不同结构成因类型。矿石的结构,从凝胶―细砂屑与砂屑颗粒由细变粗;岩石的颜色由灰褐、黑色(多陆屑、富有机炭及黄铁矿)变为浅灰、灰白色;矿层中P2O5含量随之渐增,而且CaO含量变化与P2O5含量变化同步,说明水动力条件由弱渐强,反映了沉积环境由潮汐作用为主的海湾环境。为此,陡山沱组以浅水碳酸盐优势岩相的地层条件是成磷的前提;温暖、干燥的古气候提供了有利于磷质的析出及沉积;适宜的海滩古地理环境提供了最佳的成矿场所;"黔中隆起"的古构造条件是磷矿的分布及富矿形成的最主要的控制因素。 相似文献
73.
John C. Panuska Laura Ward Good Peter A. Vadas Dennis L. Busch Asli Ozkaynak 《水文研究》2011,25(15):2329-2338
Phosphorus (P) export from agricultural lands above known threshold levels can result in adverse impacts to receiving water quality. Phosphorus loss occurs in dissolved and sediment‐bound, or particulate phosphorous (PP), forms, with the latter often dominating losses from row‐cropped systems. To target practices, land managers need good computer models and model developers need good monitoring data. Sediment monitoring data (e.g. radiometric finger printing and sediment P sorption capacity) can help identify sediment source areas and improve models, but require more sediment mass than is typically obtained by automatic sampling. This study compares a simple suspended sediment sampler developed at the University of Exeter (UE) with automatic sampling in intermittent channels draining corn and alfalfa fields. The corn field had a greater runoff coefficient (27%) than alfalfa (11%). No differences were found in enrichment ratios (sediment constituent/soil constituent) in PP (PPER) or percent loss on ignition (LOIER) between paired UE samplers on corn. The median LOIER for the UE samplers (1·9%) did not differ significantly (p > 0·13) from the automatic sampler (2·0%). The PPER from the UE samplers was on average 20% lower than the automatic samplers. A correlation (r2 = 0·75) was found between sediment PP and % LOI from automatic samplers and UE samplers for particles < 50 µm, while for > 50 µm PP concentration did not change with changes in % LOI. Sediment ammonium‐oxalate extractable metals were similarly related to LOI, with the strongest correlation for iron (r2 = 0·71) and magnesium (r2 = 0·70). Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
74.
The effect of drawdown on suspended solids and phosphorus export from Columbia Lake,Waterloo, Canada
Mike Shantz Elizabeth Dowsett Emma Canham Guillaume Tavernier Mike Stone Jonathan Price 《水文研究》2004,18(5):865-878
This study examines the effect of drawdown on the timing and magnitude of suspended solids and associated phosphorus export from a 12 ha reservoir located in an urbanized watershed in southern Ontario, Canada. Water level in Columbia Lake was lowered by 1·15 m over a 2‐week period in November 2001. The total phosphorus (TP) concentrations ranged from 63 to 486 µg L?1 in Columbia Lake and 71 to 373 µg L?1 at its outflow. All samples exceeded the Provincial Water Quality Objective of 30 µg TP L?1. Outflow concentrations of suspended solids and TP increased significantly with decreasing lake level and were attributed to the resuspension of cohesive bottom sediments that occurred at a critical threshold lake level (0·65 m below summer level). Suspended solids at the outflow consisted of flocculated cohesive materials with a median diameter (D50) of c. 5 µm. Particulate organic carbon accounted for 8·5% of the suspended solids export by mass. A total mass of 18·5 t of suspended solids and 62·6 kg TP was exported from Columbia Lake, which represents a significant pulse of sediment‐associated P to downstream environments each autumn during drawdown. The downstream impacts of this release can be minimized if the water level in Columbia Lake is lowered no more than 0·5 m below summer levels. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
75.
TRANSFERABLE PHOSPHORUS IN SEDIMENTS OF THE HUANGHE RIVER ESTUARY 'S ADJACENT WATERS 总被引:1,自引:0,他引:1
宋金明 《中国海洋湖沼学报》2001,19(1):81-86
Based on a new idea for research on cycling of marine biogenic elements, this study showed that only the leachable form phosphorus in natural grain sizes manne sediments constitutes the transferable phosphorous in the sediments. The transferable phosphorus content in the natural grain sizes surface sediments in the Huanghe River estuary adjacent waters ranges from 58.5-69.8 μg/g, accounting for only 9.1%-11.0% of the total phosphorus content, whereas the leachable form (“transferable” )phosphorus content in the sediment after it was totally ground into powder was found to be 454.8-529.2μg/g, accounting for 73.4%-89.1% of the total phosphorus. Analysis of the correlation between thebill,ass of benthos and the leachable form (“transferable” ) phosphorus showed that most of the leachableform (“transferable”) phosphorus in the totally ground sediment did not participate in the marine biogeo chemical cycling. Furthermore, a synchronous survey on benthos showed that the biornass of meio-and maero-benthos exhibited good positive correlation with the leachable form of phosphorus in the naturalgrain sizes sediment, but peorer correlation with the leachable form (“transferable”) phosphorus in the totally ground sediment, indicating that transferable phosphorus in marine sediment is the leachable form of phosphorus in the natural grain sizes sediments, and is not the previously known leachable form(“transferable”) phosphorus obtained from the totally ground sediment. 相似文献
76.
INTRODUCTIONPhosphorusisanessentialdietarynutrientforlivingorganismsandhasanimportantroleincel lularfunction ,asitisanimportantcomponentofnucleicacids,phospholipid ,phosphoproteins,ATPandseveralimportantenzymes,andcoenzymes.Inaddition ,phosphateservesasab… 相似文献
77.
调水是目前快速改善湖泊水质的有效方法之一,但是对于调水所能达到的最佳效果研究很少。以杭州西湖为例,利用环境流体动力学模型EFDC构建了西湖TP模型,对通过苏堤各桥孔的流量、外西湖分层流场和水质浓度进行了验证,分析了在现有外围调水情况下增加西湖内循环引水后西湖TP的时空变化。模拟结果表明,增加内循环引水,直接将低浓度区的水引至高浓度区,能够明显降低高浓度区的水质;低浓度区由于引水量的减小,区域内水质浓度会有一定的上升;全湖平均水质浓度基本不会发生改变。在没有增加外部引水的情况下,内循环引水可以使湖泊水体掺混更加均匀,对于防止高浓度区富营养化有很好的效果。增加内循环引水对西湖改善高浓度区水质有一定的指导意义,同时也可为相似湖泊增加内循环引水措施提供借鉴。 相似文献
78.
This paper adopts standard tests developed in temperate catchment research to determine the total phosphorus (TP) and the algal available (base‐extractable) phosphorus (NaOH–P) content of a wide range of glaciofluvial sediments from the Northern Hemisphere. We find that the TP content of these sediments is broadly similar to the P content of major rock types in Earth's crust (230–670 µgP/g) and so the TP yields of glacier basins may be high owing to the efficacy of suspended sediment evacuation by glacial meltwaters. We show that this is best achieved where subglacial drainage systems are present. The NaOH–P pool of the sediments is found to be low (1–23 µgP/g) relative to the TP pool and also to the NaOH–P pool of suspended sediments in temperate, non‐glacierized catchments. This most probably reflects the restricted duration of intimate contact between dilute meltwaters and glacial suspended sediments during the ablation season. Thus, despite the high surface‐area:volume ratio of glacial suspended sediments, the potential for P adsorption to mineral surfaces following release by dissolution is also low. Further, sorption experiments and sequential extraction tests conducted using glacial suspended sediments from two Svalbard catchments indicate that the generation of reactive secondary minerals (e.g. Fe‐ and other hydroxides) with a strong capacity to scavenge P from solution (and thereby promote the continued dissolution of P) may also be limited by the short residence times. Most P is therefore associated with poorly weathered, calcite/apatite‐rich mineral phases. However, we use examples from the Svalbard glacier basins (Austre Brøggerbreen and Midre Lovénbreen) to show that the high sediment yields of glaciers may result in appreciable NaOH–P loading of ice‐marginal receiving waters. Again, the importance of subglacial drainage is highlighted, as it produces a major, episodic release of NaOH–P at Midre Lovénbreen that results in a yield (8·2 kg NaOH–P/km2/year) more than one order of magnitude greater than that at Austre Brøggerbreen (where subglacial drainage is absent and the yield is 0·48 kg NaOH‐P/km2/year). Therefore, as since both detrimental and beneficial effects of sediment‐bound P loading in ice marginal receiving waters are possible (i.e. either reduced primary productivity owing to increased turbidity or P fertilization following desorption) there is a pressing need to assess the ambient P status of such environments and also the capacity for ice‐marginal ecosystems to adapt to such inputs. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
79.
DISTRIBUTIONS OF TOTAL, INORGANIC AND ORGANIC PHOSPHORUS IN THE SEDIMENTS NEAR THE HUANGHE RIVER ESTUARY 总被引:1,自引:0,他引:1
For some hundred surface sediment samples from five cores taken in two cruises near the Huanghe River Estuary, total phosphorus (TP (.inorganic phosphorus (IP (and organic phosphorus (OP)were determined.On the average, 527×10-6, 455×10~6 and 72×10-6 were found for TP,IP and OP for the surface sediments taken in the two cruises. The distribution of OP and IP was controlled by the sample particle size: OP content increased with the decreasing of the sample particle size, while the maximal value of IP was found in the silt fraction due to the existence of apatite in our samples. Vertical distributions reflected well the channel change of the Huanghe River. Results from the multiple regressions between the three forms of phosphorus and the percentages of different particle size agreed well with the analytical data. 相似文献
80.