Average Total Phosphorus Concentration Research Articles

Strategies of <i>Ceratophyllum demersum</i> to govern algal phosphorus-acquisition and algal proliferation

水体浮游植物具有捕获利用磷的能力以及沉水植物能够显著抑制水体中藻类生长已得到国内外广泛共识，但相应的潜在机制尚缺乏深入了解.本研究选取金鱼藻（Ceratophyllum demersum）为研究对象，基于室内模拟实验，探讨了沉水植物调控浮游植物捕获磷与过度生长的机制.结果显示，尽管未种植金鱼藻的对照组上覆水中总磷、总溶解态磷和可溶性活性磷的平均浓度均显著高于种植金鱼藻的实验组（约4倍），但是两个系统中这3种磷浓度随时间的变化趋势均符合S形的对数曲线.实验组藻类密度、有效光量子产量、总碱性磷酸酶活性（TAPA）以及细颗粒碱性磷酸酶活性（细颗粒APA）也远低于对照组.此外，对照组中粗颗粒碱性磷酸酶活性（粗颗粒APA）占TAPA的44.7%，显著高于细颗粒APA.结构方程模型结果表明，对照组水体藻类密度对TAPA具有直接的正向作用，而金鱼藻的生长显著弱化了不同形态磷与APA、藻类密度、细菌动力以及光量子产量之间的相互作用.这说明沉水植物对水体浮游植物生长的调控具有多种策略.;Phosphorus acquisition by algae and the algal growth inhibition governed by submerged macrophytes have been long-term observed, but the general underlying mechanism is not clear. Here, we assembled mesocosms and subjected them to two treatment regimes, one planted with Ceratophyllum demersum and the other unplanted control, to address the causal mechanisms. The results showed that the average concentration of total phosphorus, total dissolved phosphorus and soluble reactive phosphorus in the unplanted control were significantly higher (about 4 folds) than those in system with macrophyte control, but all their observed values changed with time following S-shaped Logistic curves. Additionally, significantly higher values of algal density, quantum yield, total alkaline phosphatase (APA) and bacterial APA were also detected in the control. And the algal alkaline phosphatase, as the predominant component accounted for up to 44.7% of the total APA, was significantly higher than that of bacterial APA. Structural equation modeling indicated that significant positive influence on total APA only occurred in the unplanted control, and C. demersum growth had a significant decoupling effect on the relationship between different forms of phosphorus and APA, algal density, bacteria dynamic and quantum yield. These results suggested that submerged macrophytes have different tactics to govern algal proliferation.

Hodnotenie koncentr�cie anorganick�ch foriem dus�ka a fosforu pod lesn�m ekosyst�mom vodn�ho toku Caradick� potok

The aim of this study was to evaluate of concentrations of nitrate, ammonium and nitrite nitrogen, total and phosphate phosphorus under the forest ecosystem Caradice stream during 2005-2010. The average concentration of N-NO3- for the whole of the monitored period was 1.76 mg*dm-3. Its highest average concentrations in all monitored years were generally in the winter. The average concentration of ammonia nitrogen during the whole monitored period was 0.14 mg*dm-3. Minimum average concentrations over the entire observed period were recorded in the winter period and maximum during the summer and autumn periods. The average nitrite nitrogen concentration over the entire monitored period was 0.025 mg*dm-3. Depending on the time of collection, its lowest average concentration was recorded in January and the highest in June and September. The average total phosphorus concentration under the forest ecosystem of the Cadadický stream for the whole monitored period was 0.676 mg*dm-3. Its lowest average value for the whole reporting period was recorded in February and the highest in November. The average concentration of P-PO43- for the whole reference period was 0.203 mg*dm-3. Its lowest average concentration, depending on the collection time, was found in January and the highest in August.

Vertical Distribution and Pollution Risk Assessment of Nitrogen, Phosphorus, and Organic Matter in Sediment of Inflowing Rivers of Erhai Lake Estuarine Wetland in Wet and Dry Seasons

The estuarine wetland of Luoshijiang River, which flows into Erhai Lake in Yunnan province, was regarded as the typical research object. Sediment samples in the estuarine wetland of Luoshijiang River were collected by the cylindrical sediment sampler and the samples were from surface layer (0-10cm), middle layer (10-30 cm), and bottom layer (30-60 cm). The vertical distribution of total nitrogen, total phosphorus, and total organic material in dry and rainy season was analyzed and contamination risk assessment of sediment was accomplished. The results showed that: ① In dry season, average concentrations of total nitrogen in sediment on surface, middle and bottom layer at estuarine wetland of Luoshijiang River were respectively 1.734, 1.453 and 1.255 g·kg-1, the average concentrations of total phosphorus were respectively 1.085, 1.034 and 0.992 g·kg-1, the average concentrations of organic material were respectively 59.051, 47.730 and 42.133 g·kg-1. In rainy season, average concentrations of total nitrogen in sediment on surface, middle and bottom layer at estuarine wetland of Luoshijiang River were respectively 1.147, 0.948 and 0.895 g·kg-1, the average concentrations of total phosphorus were respectively 0.599, 0.523 and 0.519 g·kg-1, the average concentrations of organic material were respectively 53.098, 46.897 and 43.395 g·kg-1. ② Single factor pollution index, organic nitrogen and organic index assessment were used to evaluate the contamination level of sediment, the assessment results showed that: In dry season, the contamination level of nitrogen and phosphorus in sediment was on severe level, organic material contamination was on medium level. In rainy season, the contamination levels of ON and OI were medium, and that of PI was mild. Generally, the contamination levels of nitrogen, phosphorus and organic material in sediment tendency were as follows: dry season>rainy season, and the pollution index of each layer followed the sequence of surface layer > middle layer > bottom layer, and the most extraordinary contamination of them on surface layer was uncovered whatever the season was. ③ Pollution origin of estuarine wetland of Luoshijiang River in dry and wet season had great differences, it was mainly the exogenous source in dry season, but it was the internal source in wet season; The potential risk of release of nutrient salt of sediment in dry season was higher than the wet, and the risk in the surface layer was the highest.

Increasing phytoplankton-available phosphorus and inhibition of macrophyte on phytoplankton bloom.

We assembled mesocosms to address the coherent mechanisms that an increasing phosphorus (P) concentration in water columns coupled with the phytoplankton bloom and identify the performance gap of regulating phytoplankton growth between two macrophyte species, Ceratophyllum demersum L. and Vallisneria spiralis L. Intense alkaline phosphatase activities (APA) were observed in the unplanted control, with their predominant part, phytoplankton APA (accounting for up to 44.7% of the total APA), and another large share, bacterial APA. These correspond with the large average concentration of total phosphorus (TP), total dissolved phosphorus (TDP) and soluble reactive (SRP) as well as high phytoplankton density in the water column. The consistency among P concentrations, phytoplankton density and APA, together with the positive impact of phytoplankton density on total APA revealed by the structural equation modelling (SEM), indicates that facilitated APA levels in water is an essential strategy for phytoplankton to enhance the available P. Furthermore, a positive interaction between phytoplankton APA and bacteria APA was detected, suggesting a potential collaboration between phytoplankton and bacteria to boost available P content in the water column. Both macrophyte species had a prominent performance on regulating phytoplankton proliferation. The phytoplankton density and quantum yield in C. demersum systems were all significantly lower (33.8% and 24.0%) than those in V. spiralis systems. Additionally, a greater decoupling effect of C. demersum on the relationship between P, APA, phytoplankton density, bacteria dynamic and quantum yield was revealed by SEM. These results imply that the preferred tactic of different species could lead to the performance gap.

Influence of the particle size of carbonate-siliceous rock on the efficiency of phosphorous removal from domestic wastewater

The aim of the study was to determine the influence of the particle size of carbonate–silica rock (opoka) used in rock filters on the efficiency of phosphorus removal from domestic wastewater. The investigations were carried out in a laboratory using a model consisting of three vertical flow filters with carbonate–silica rock of different particle sizes (G1=1–2mm; G2=2–5mm; G3=5–10mm). The tested rock was subjected to decarbonising at 900°C and consisted primarily of 51.7% SiO2, 23.2% CaO, and 7.6% Al2O3. In the first three weeks of the study (1–3), the hydraulic load of each filter was Q1=0.72l/day and the hydraulic residence time was HRT1=24h; in the next three weeks (4–6) Q2=1.08l/day and HRT2=16h, and during the last three weeks (7–9) Q3=1.44l/day and HRT3=12h. A significant influence of the size of rock particles and the hydraulic load (hydraulic residence time) on the efficiency of total phosphorus removal and on phosphorus concentration in the wastewater discharged from the system was observed (α=0.05). Statistically, the best removal of phosphorus from wastewater – an average of 97%, was found in the substrate with the smallest particle size (rock G1, 1–2mm) at the lowest hydraulic load of 0.72l/day and at a hydraulic residence time of 24h. The lowest phosphorus removal efficiency was observed in the filter containing rock G3 with a particle size of 5–10mm (mean <60%). The average concentration of total phosphorus in wastewater flowing out from filter G1 was 0.23mg/l, which was much below the limit values specified by EU regulations. The overall phosphorus load removed during the study period (nine weeks) in the filter with fraction G1 was 0.38g/kg of rock, in the filter with G2-0.30g/kg of rock, in the filter G3-0.28g/kg of rock. The load of phosphorus removed during this period not characterized the full sorption capacity of the rock. The study showed that the rock subjected to decarbonising at 900°C could be successfully used to remove phosphorus from domestic wastewater, especially in areas where phosphorus removal requirements are very high (Ptot.<2mg/l).

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources.

Eutrophication is one of the greatest threats to global freshwater ecosystems. The phytoplankton responses to nutrient inputs vary in different water bodies, so it is particularly important to determine the nutrient thresholds and synergistic interactions between nutrients in different freshwater ecosystems. Field sampling and bioassay experiments were conducted to determine the thresholds of soluble reactive phosphorus (SRP), nitrate-nitrogen (NO3-N), and ammonium-nitrogen (NH4-N) in Miyun Reservoir. A separate nutrient addition bioassay was designed to assess the synergistic interactions between these nutrients. Chlorophyll a (Chl a) concentrations were used to estimate phytoplankton biomass. The results showed the following: (1) nutrient threshold bioassay indicated that eutrophication thresholds of SRP, NO3-N, and NH4-N should be targeted at below 0.04mg P L-1, 0.5mg NL-1, and 0.3mg NL-1, respectively, to limit the growth of phytoplankton. (2) The stimulatory effect of "NH4-N plus P" on phytoplankton biomass was greater than "NO3-N plus P" at the same N concentration, and "NH4-N plus NO3-N" did not show such associated stimulatory effect as "NH4-N plus P" or "NO3-N plus P". (3) The average concentrations of total phosphorus (TP), NO3-N, and NH4-N in Miyun Reservior were 0.017mg P L-1, 0.620mg NL-1, and 0.143mg NL-1, respectively. The reservoir-wide average Chl a is below 20μgL-1 on an annual basis. (4) Ammonium was an important factor for the growth of phytoplankton and inputs of both NH4-N and NO3-N should be reduced to control bloom formation. Our findings imply that although P load reduction is important, appropriate reductions of all forms of N in watershed is recommended in the nutrient management strategy for Miyun Reservoir.

Distribution patterns and dynamics of phosphorus forms in the overlying water and sediment of Dongting Lake

Abstract Dongting Lake is a typical shallow lake in the lower Yangtze region and is the second largest freshwater lake in China. The distribution, speciation, and sediment release characteristics of phosphorus (P) were investigated by analyzing sediment and water samples collected during high and low flow periods. The average concentration (range) of total phosphorus (TP) in the water was 0.05 mg L − 1 (0.02 ~ 0.09 mg L − 1 ), while the value in sediment was 703 mg kg − 1 (466 ~ 869 mg kg − 1 ). The concentrations of TP and different P forms decreased as depth increased. Inorganic phosphorus was the dominant form of P, accounting for 72% of TP. The bioavailable P was a relatively large portion of TP, indicating a high risk of P release to overlying water. The Langmuir equation can well describe the P isotherm adsorption characteristics in sediment. The amount of P desorption from sediment tended to increase with increasing concentrations of adsorbed P.

Estimation of long-term Ca2+ loss through outlet flow from an agricultural watershed and the influencing factors

Soil Ca(2+) loss from agricultural lands through surface runoff can accelerate soil acidification and render soil degradation, but the characteristics of Ca(2+) loss and influencing factors in watershed scale are unclear. This study was carried out in a watershed with various land uses in a subtropical region of China. The outlet flow was automatically monitored every 5min all year round, and the water samples were collected twice a year from 2001 to 2011. The concentrations of Ca(2+), Mg(2+), K(+), total nitrogen (TN), and total phosphorus (TP) of water samples were measured. The dynamic losses of the nutrients through the outlet flow were estimated, and the relationships between the nutrient losses and rainfall intensity as well as antecedent soil moisture were investigated. The results showed that great variations of nutrient concentrations and losses appeared during the investigation period. The average concentrations of Ca(2+), Mg(2+), K(+), TN, and TP were 0.43, 0.08, 0.10, 0.19, and 0.003mmolL(-1), respectively. The average Ca(2+) loss reached 1493.79molha(-1)year(-1) and was several times higher than for Mg(2+), K(+), and TN, about 140 times higher than for TP. Rainfall intensity had remarkable effects on Ca(2+) concentration (P < 0.01) and loss (P < 0.05) when it reached rainstorm level (50mmday(-1)), while a quadratic relationship was observed between antecedent soil moisture and Ca(2+) concentration only when rainfall intensity was less than 50mmday(-1). In a word, much greater amounts of Ca(2+) were lost from the watershed, and this may be one important contributor to the increasing acidification of acidic soils in subtropical regions.

Trophic state decrease after lanthanum-modified bentonite (Phoslock) application to a hyper-eutrophic polymictic urban lake frequented by Canada geese (Branta canadensis)

Urban lakes are important assets to highly populated regions; however, extensive usage and other influences degrade their water quality, which then requires rehabilitation and maintenance. Hyper-eutrophic Swan Lake, Greater Toronto, Canada (5.5 ha, 4.4 m maximum depth) was a gravel pit that became degraded by elevated total phosphorus (TP) concentrations, mostly from internal P sources. Because Swan Lake is a terminal lake with limited flushing and small external load, a phosphate adsorbing and sediment capping agent, lanthanum-modified bentonite (Phoslock), was applied in spring 2013 to intercept the internal load. Average TP concentration decreased from 0.247 to 0.099 mg/L in the first and 0.060 mg/L in the second post-treatment year. A TP mass balance model adequately predicted post-treatment annual average TP concentration by not including the pre-treatment internal load estimate of 650 to 1100 mg/m2/yr. Phytoplankton biomass decreased only in the second post-treatment year, when Secchi transparency (highly correlated with chlorophyll concentration) increased to a growing season average of 1.4 m (range 0.7–2.7) compared to 0.5 m (0.37–0.63) before treatment. We explain the lack of response in the first treatment year with a relatively late application (29 Apr–1 May 2013), when P released from the winter bottom sediments had already been taken up by phytoplankton. Recently, a growing population of waterfowl (mostly Canada goose, Branta canadensis) were the highest contributors of nutrients (75%), as indicated by a mass balance based on literature-derived goose P export and biweekly bird census. We recommend waterfowl management or repeated treatment to further improve water quality.

PREDICTING THE TROPHIC STATUS OF SOME LAKES OF KAZAKHSTAN

A method for predicting the lake trophic status relying on wintertime monitoring data was developed. The technique is based on A. G. Volokhonskii’s approach, according to which the values of the minimum energy costs calculated for the virtual model of the process of involving mineral nutrients in phytoplankton cells are universal criteria of these nutrients’ availability to phytoplankton. Statistically significant one-parameter linear dependence between the average annual concentration of total phosphorus (P t ) and the values of minimum energy costs ( Ep ), which characterize mineral phosphorus levels in February, was detected. A classification of the trophic status of lakes ofKazakhstan depending on the values of the minimum energy costs of mineral phosphorus in February was developed.

Managing phosphorus loads from agricultural cranberry bogs to restore White Island Pond

The historical increase in phosphorus fertilizer application on commercial cranberry bogs from ∼1960 to 2008 is associated with the decline in water quality of White Island Pond, Plymouth/Wareham, Massachusetts. A total maximum daily load (TMDL) and a memorandum of agreement (MOA) with cooperating groups required specific cranberry bog management practices to restore the lake. We used a cooperative approach among the University of Massachusetts, the growers, and the town with the assistance of a series of US Environmental Protection Agency 319 Program grants focusing on reduced fertilizer rates, discharge diversions, and an aluminum treatment of the lake to address the excess phosphorus inputs. In the East Basin of the pond, where total phosphorus (TP) summer concentrations previously averaged 82 μg/L, the concentrations dropped 41% over 4 years to 48 μg/L after fertilizer reductions and diversions of bog discharge floodwaters occurred at the cranberry bogs. After this source of phosphorus was controlled, an aluminum treatment was applied to East Basin in 2013 and to both basins in 2014. Subsequently, TP concentrations fell an additional 44% (85% total) in East Basin to a concentration of 12 μg/L in 2014. Summer average TP concentrations across the basins were 13 μg/L and met the TMDL target of 19 μg/L. The transparency has been restored, and the frequent cyanobacteria blooms have been eliminated. The new management guidance for bogs in the TMDL appendix offers a cooperative path toward restoration of lakes and streams while maintaining cranberry yields.

Distribution characteristics of phosphorus in the sediments and overlying water of Poyang lake.

Phosphorus (P) is a key indicator of the aquatic organism growth and eutrophication in lakes. The distribution and speciation of P and its release characteristics from sediments were investigated by analyzing sediment and water samples collected during high flow and low flow periods. Results showed that the average concentrations (ranges) of total phosphorus (TP) in the surface and deep water were 0.06 mg L-1 (0.03–0.13 mg L-1) and 0.15 mg L-1 (0.06–0.33 mg L-1), respectively, while the average concentration (range) of TP in sediments was 709.17 mg kg-1 (544.76–932.11 mg kg-1). The concentrations of TP and different forms of P varied spatially in the surface sediments, displaying a decreasing trend from south to north. P also varied topographically from estuarine areas to lake areas. The vertical distribution of TP and different forms of P were observed to decrease as depth increased. The P concentrations during the low flow period were higher than those during the high flow period. Inorganic phosphorus (IP) was the dominant form of P, accounting for 61%–82% of TP. The concentration of bioavailable phosphorus in sediments was relatively large, indicating a high risk of release to overlying water. The simulation experiment of P release from sediments showed that the release was relatively fast in the first 0-5 min and then decreased to a plateau after 1 hr. Approximately 84–89% of the maximum amount of P was released during the first hour.

Long-term trends in nutrient concentrations in Polish coastal rivers

This paper analyzes the long-term changes in concentrations of nutrients in seven rivers located in the Polish part of the southern Baltic coastal zone in response to economic changes that took place between 1988 and 2013. These changes included: construction or modernization of 390 biological waste water treatment plants, reduction of untreated municipal waste waters discharged into water and soil, a decrease in fertilizer application, and a decline in animal production by about 60% LU. Statistically significant downward trends in nutrients concentrations were observed in six out of seven studied rivers. The mean annual concentration of Ntot changed from about 3.6 to 3.8 mg N dm−3 in the late 1980's and early 1990's to about 2.2 mg N dm−3 in the last 5 years of the study period. The average concentrations of total phosphorus showed the highest values between 1989 and 1991, with a maximum of about 0.5 mg P dm−3 in 1990, and were then gradually decreasing to about 0.12 mg P dm−3 in the late 2000's and early 2010's. Additionally, during the last 25 years the Ntot/Ptot ratio increased significantly, which is indicative of the improvement of ecological status of studied rivers. Correlation analyses indicate that significant reduction in point emission of nutrients and in consumption of organic fertilizer played an important role in the change of nutrient concentration in study rivers.

Spatio-temporal variation of algae and eutrophic status of Lake Zhelin, Jiangxi Province

Lake Zhelin in Jiangxi Province is among the first batch of demonstrative lakes in the"High Quality and Healthy Lake Plan"initiated by Chinese government. To study its spatio-temporal variation of algae and water eutrophication status,sampling sites in both Lake Zhelin and rivers flow into it were investigated from August 2012 to July 2013. The results showed that Lake Zhelin belongs to mesotrophic waters,with average total nitrogen and phosphorus concentration 1 mg / L and 0. 05 mg / L,respectively. The development of algae in Lake Zhelin mainly shifted between cyanobacteria( Microcystis and Anabaena) in the summer and diatom( Melosira,Cyllotella and Synedra) in the winter. Cyanobacteria bloom happened in the west of the lake,with a much higher abundance than that in the east. There are three main drinking water sources in Lake Zhelin and one of them suffered from cyanobacterial bloom during summer. However,microcystin concentration in the drinking water was still far below the safety guideline 1 μg / L. The algae cell abundance in the three main rivers into Lake Zhelin was still low,and the algae cell abundance in Yangang River was near 1 × 107 cells / L in both summer and winter. The decrease of input water volume and water level in Lake Zhelin in dry seasons,stratification of the water column,low water transparency together with long retention time of the lake water were the main causes of the blooms in Lake Zhelin.

Nutrient Composition of Dust Emitted from Poultry Broiler Houses in Northwest Arkansas

A substantial body of research has been conducted on the potential water quality impairments associated with land application of poultry broiler litter. However, until recently, little attention has focused on the potential for nutrient runoff from dust emitted from broiler production houses despite related air quality concerns raised by the United States (US) Environmental Protection Agency. The objective of this study was to characterize the composition of broiler house dust (BHD) and compare BHD composition to that of broiler litter (BL). Dust composition varied significantly (P < 0.05) among facilities operated by different integrator companies, likely due to differences in feed and house management among integrators. Specifically, BHD pH was lower (P < 0.05) in Facility 1 than in Facilities 2 and 3, which did not differ, whereas BHD K and Ca were greatest (P < 0.05) in Facility 1 and 2, respectively. The facility average moisture content of BHD was at least 1.9 times lower than that for the BL from the same facility. The facility average total phosphorus (TP) and water extractable phosphorus (WEP) concentrations in BHD were at least 1.2 and 1.6 times greater, respectively, than that for BL from the same facility. The greater WEP in BHD than in BL is of particular environmental importance given that extensive research shows WEP to be a major variable influencing P runoff risk. The facility average total nitrogen (TN) concentration in BHD was at least 3.0 times greater than that for BL from the same facility. As TP, WEP, and TN are greater in BHD than in BL, there is a greater risk of nutrient enrichment of runoff from an equivalent mass of BHD than BL. The results of this study highlight the need for careful management of dust emissions from broiler houses and a need for conservation practices to minimize the risk of BHD increasing nutrient runoff and its loss to waters of the US.

Monitoring of the water's quality of Moulouya River: main tributary of Hassan II dam (Province of Midelt, Morocco)

The Watershed of Hassan II dam contains a fairly well developed river system, including the Moulouya River and Ansegmir River whose flows are almost permanent. This watershed drains an area of ​​3300Km ² and it is subject to anthropogenic disturbances that can have a negative effect on the quality of water supplied to the dam whose health is affected by the intrinsic characteristics of the watershed. Indeed, Moulouya receives throughout its headwaters domestic discharges from local populations and pollutants from agriculture developed throughout the valley of the upstream part of the wadi. The objective of this work, spread over the period from September 2011 to August 2012, is to monitor the physico-chemical quality of water of Moulouya river at a station situated just in upstream of the confluence river-lake of the dam, eventually leading to an estimate of the quantity and quality of pollution injected by this River in the Hassan II dam. It shows that the average concentrations of total suspended solids, total phosphorus and nitrate (expressed as nitrate ion) in water injected into the dam, were in the range of 39.21 mg/L, 212.83 mg/L and 6.23 mg/L respectively.

Protecting the Florida Everglades wetlands with wetlands: Can stormwater phosphorus be reduced to oligotrophic conditions?

The Florida Everglades is being threatened by high-nutrient stormwater coming from agricultural runoff. The main nutrient problem is phosphorus, which causes the highly oligotrophic sawgrass (Cladium jamaicense) communities in the northern Everglades to become eutrophic Typha latifolia/T. domingensis communities. Current government directives require that the total phosphorus concentration of storm water drainage into the Everglades be limited to approximately 10ppb (μg-P/L). Over 23,000ha treatment wetlands, referred to locally as stormwater treatment areas (STAs), have been created from farmland to treat the stormwater. They are generally effective in removing 60–80% of the total phosphorus; however, the 10ppb goal has rarely been achieved. A three-year experiment, involving mesocosms planted with Everglades-native wetland plants was conducted in the Florida Everglades from March 2010 to March 2013. Eighteen flow-through mesocosms (6m×1m×1m with 40-cm water depth) received about 2.6cm/day inflow. The eighteen mesocosms were randomly assigned with six different plant communities with three replicates of each treatment, consisting of sawgrass (C. jamaicense); waterlily (Nymphaea odorata); cattail (Typha domingensis); submerged aquatic vegetation (SAV) including Najas guadalupensis, and Chara sp. and a Nymphaea–Eleocharis sp. mixed community; and soil without vegetation as a control. Total phosphorus (TP) in the inflow water was 25±1μg-P/L (n=55) over the 3 years. Through 2012 the average outflow of all of the treatments was 34±1μg-P/L, a 51% decrease from the average outflow of 69±6μg-P/L for 2011. Outflows began to be routinely lower than the inflow in the 3rd year of the study. The average total phosphorus concentration decreased overall to 19±1 (n=5) at the end of the study in 2013 suggesting that the suspected phosphorus reflux from the mesocosm soils into the water column slowed after 2–2.5 years of mesocosm operation. Comparing outflows of the individual treatments for 2013, the Nymphaea, control/Chara, and Typha treatments were lower (p<0.05) than the inflow with average outflow concentration of 11±1, 15±3 and 16±1μg-P/L respectively. When the 2013 data are isolated, 4 of the 6 vegetation treatments showed total phosphorus removal, ranging from mixed community (17% removal), to Typha (28% removal), to the control (34% removal) and to Nymphaea (51% removal). We conclude that any treatment wetland constructed with local Florida soils and designed to achieve low (∼10–15ppb P) concentrations would probably take a minimum of 2 years to become sinks of phosphorus. We also conclude that wetlands can be created to achieve these low thresholds if low TP loading and self-design strategies are incorporated into the project design.

Water-Quality Assessment on Butterfly Lake in Guangdong Ocean University, China

Butterfly Lake provides an important function of ecological environment and campus service for Guangdong Ocean University. Based on the data which were collected in March,May, September and December in 2013, the water environment quality of Butterfly Lake was assessed. The results show that the key pollutant of Butterfly Lake is total phosphorus (TP). The average concentration of TP is worse than the national quality standards for Class V. The water quality appears an obvious difference in different monitoring time. In September the water quality is the best. The average of single parameter pollution index (Sj) is 0.75 and the water quality belongs to good environment area. The average of integrated parameter pollution index (WQI) is 1.76 and the water quality belongs to light pollution area. In December the water quality is the worst. Sj and WQI is 1.14 and 3.14. The water quality belongs to light pollution area and moderate pollution area, respectively. The comprehensive trophic state index is 70.38 in December. The eutrophication level is hyper eutropher. The other monitoring time belongs to middle eutropher. In order to improve the water quality of Butterfly Lake,the valid measure is to strengthen the management of wastewater discharge from the laboratory and the dormitory.

낙동강의 환경요인이 조류군집 구성에 미치는 영향

This study was carried out to investigate algal community structures and their correlations with environmental factors on five weir areas in the Nakdong River, South Korea. Water qualities, hydrodynamics, meteorological conditions and algal species compositions were observed in studied sites from May 2010 to Dec. 2013. Results showed that average total phosphorus concentration of 2013 was decreased by 52.4% in comparing with that from 2010 to 2011. Chlorophyll.a concentrations were positive significant with water temperature, pH, total phosphorus and total nitrogen, but is not significant with turbidity and suspended solids. Seasonal successions of algae were observed that Stephanodiscus sp. was dominant species with 65.3% of dominant frequency in studied site. Large algal biomass of the low temperature-adapted diatoms were observed during temperature range of <TEX>$4{\sim}9^{\circ}C$</TEX>, but large cyanobacterial biomass mainly during high temperature period ranged from <TEX>$22^{\circ}C$</TEX> to <TEX>$32^{\circ}C$</TEX>. Microcystis sp. dominated during high water temperature in summer. The yearly correlations of algal biomass with accumulated solar radiations were not significant but seasonal correlations of summer from June to August were significant with correlation coefficient 0.33 (p<0.05). There were not significant correlations between turbidities and algal biomass. Turbidity and suspended solids concentrations were not significant correlation with algal biomass. According to the results, algal communities had strong correlation with water temperature and had partially correlation with solar radiation. For an effective management of algal blooms, water managers should survey with more long-term monitoring of various environmental factors and algal communities.

Ionic composition of terrestrial surface waters in Maritime Antarctic and the processes involved in formation

AbstractThe qualitative and quantitative composition of major ions and nutrient compounds in surface waters and soils of the west coast of Admiralty Bay (King George Island, West Antarctica) was investigated together with the effect of soil-forming processes and atmospheric precipitation on the ionic composition of surface waters. In the water bodies studied, Cl- and Na+ were dominant major ions (average concentrations: 1102.2 and 930.9 μM, respectively). Average concentrations of the other major anions ranged from 2.80 μM (F-) to 81.64 μM (SO42-) and major cations ranged from 12.46 μM (K+) to 130.76 μM (Mg2+). Average concentrations of total reactive phosphorus, N-NO2-, N-NO3- and N-NH4+ amounted to 1.374, 0.410, 6.299 and 1.490 μM, respectively. Average concentrations of Ca, Mg, Na, K, N and P in the surface layer of the soil equalled 16.8, 15.9, 6.4, 3.6, 0.646 and 0.744 g kg-1, respectively. The calculated Na+/Cl-, Ca2+/Mg2+, Ca2+/Na+ and HCO3-/Cl- ratios revealed that atmospheric precipitation was the main source of major ions. We conclude that the ionic composition of the waters of the western coast of Admiralty Bay differ from surface waters of Continental Antarctica.