Phosphorus removal from secondary effluents through integrated constructed treatment system

The treatment capacity of an integrated constructed treatment system (CTS) was explored which was designed to reduce phosphorus (P) from secondary effluents. The integrated CTS was combined with vertical-flow constructed wetland, floating bed and sand filter. The vertical wetland was filled from the bottom to the top with gravels, steel slag and peat. Vetiverzizanioides (L.) Nash was selected to grow in the vertical constructed wetland while Coixlacrymajobi L. was grown in floating bed. The results suggested that integrated CTS displayed excellent removal efficiency for chemical oxygen demand (COD), dissolved phosphorus (DP), and total phosphorus (TP). The average COD removal efficiency of the integrated CTS was 90.45% after 40 days of operation, the average DP and TP removal efficiencies of the integrated CTS were 97.43% and 96.40%, respectively. The integrated CTS has good potential in removing COD as well as P from secondary effluents.     

Potential use of mangroves as constructed wetland for municipal sewage treatment in Futian,Shenzhen, China

A pilot-scale mangrove wetland was constructed in Futian, Shenzhen for municipal sewage treatment. Three identical belts (length: 33 m, width: 3 m, depth: 0.5 m) were filled with stone (bottom), gravel and mangrove sand (surface). Seedlings of two native mangrove species (Kandelia candel, Aegiceras corniculatum) and one exotic species (Sonneratia caseolaris) were transplanted to the belts with one species for each belt. The hydraulic loading was 5 m³ d⁻¹ and hydraulic retention time 3 d. High levels of removal of COD, BOD₅, TN, TP and NH₃–N were obtained. The treatment efficiency of S. caseolaris and A. corniculatum was higher than that of K. candel. Faster plant growth was obtained for S. caseolaris. The substrate in the S. caseolaris belt also showed higher enzyme activities including dehydrogenase, cellulase, phosphatase, urease and β-glucosidase. The removal rates of organic matter and nutrients were positively correlated with plant growth. The results indicated that mangroves could be used in a constructed wetland for municipal sewage treatment, providing post-treatment to remove coliforms was also included.     

Effects of salinity on treatment of municipal wastewater by constructed mangrove wetland microcosms

The effects of salinity on the removal of dissolved organic carbon and nutrients from municipal wastewater by constructed mangrove microcosms planted with Aegiceras corniculatum were investigated. During the four-month wastewater treatment, the treatment efficiency was reduced by high salinity, and the removal percentages of dissolved organic carbon, ammonia-N and inorganic N dropped from 91% to 71%, from 98% to 83% and from 78% to 56%, respectively, with salinity increasing from 0 to 30 parts per thousands (ppt). In spite of such inhibition at high salinity, 100% of the effluents discharge from the constructed mangrove microcosms still complied with the discharge standards set by the Hong Kong Government for Coastal Water Control Zones. These results suggested that constructed mangrove wetland treatment systems were promising to effectively treat municipal wastewater, even those with high salinity. In addition, the denitrification potential in soil was found to be retarded by the high salinity while mangrove plants grew best at 15 ppt salinity condition.     

种植不同植物的人工湿地深度处理城镇污水处理厂尾水的中试研究

利用种植不同植物的人工湿地对污水厂尾水进行深度处理以达到更严格的排放标准.利用5块尺寸一致的中试规模人工湿地,以潮汐流作为运行方式,研究不同植物对尾水的处理效果.经过一年的实验,结果表明：5块人工湿地出水各指标均能达到提升标准的排放要求.在不同植物的去污效果对比实验中,种植芦苇（Phragmites communis）的人工湿地对化学需氧量（COD）、氨氮和总氮（TN）的平均去除率均为最高,分别为24.01%、68.15%和92.70%;种植风车草（Cyperus alternifolius）的人工湿地对TP的平均去除率最高,为71.68%.在不同季节的去污效果对比实验中,春季芦苇湿地对COD、氨氮和TN的去除效果最好,平均去除率分别为52.51%、76.06%和92.04%,美人蕉（Canna indica）湿地对TP去除效果最好,平均去除率为66.72%;夏季对COD、氨氮、TP和TN处理效果最好的分别是种植丝带草（Phalaris arundinacea）、菖蒲（Acorus calamus）、风车草和芦苇的人工湿地,平均去除率分别为15.83%、78.11%、67.30%和91.73%;秋季对COD、氨氮、TP、TN处理效果最好的分别是种植芦苇、丝带草、风车草、美人蕉的人工湿地,平均去除率分别为12.19%、58.82%、83.16%和94.01%;冬季对COD去除效果最好的是种植丝带草的人工湿地,平均去除率为33.39%,对氨氮、TP处理效果最好的是种植美人蕉的人工湿地,平均去除率分别为76.33%和79.43%,对TN处理效果最好的是种植芦苇的人工湿地,平均去除率为94.97%.在以后的实际工程中,可以考虑用种植不同季节、不同指标对应的最佳去污植物为主,并且搭配种植其他植物的人工湿地进行污水厂尾水的深度处理.     

Effects of fish and macrophytes on phytoplankton and zooplankton community structure in a subtropical freshwater reservoir

Excessive macrophyte biomass and cyanobacterial blooms associated with eutrophication and possibly exotic fish frequently compromise freshwater systems. In this study, 20 large (∼3.2 m³), replicated enclosures were used to investigate the effects of piscivorous Australian bass (Macquaria novemaculeata), planktivorous gambusia (Gambusia holbrooki (Girard)), benthivorous carp (Cyprinus carpio), and macrophyte removal on water quality, as well as trophic interactions within the enclosures. Fish effects on reservoir water quality were carp > gambusia > bass. Cryptomonads spp. (54,083 cells/mL) and Anabaena spp. (47,983 cells/mL) increased significantly (63 and 23 fold, respectively) in carp enclosures, possibly because of physiological adaptation to low light, high turbidity, total phosphorus concentrations (TP) and low TN: TP ratios (N-limitation); a consequence of carp benthic grazing. Carp and gambusia caused an unconventional shift from smaller to medium sized zooplankton (e.g. Boeckella sp., Bosmina meridionalis), possibly a result of copepod nauplius grazing. In the subtropical system studied, fish-induced nutrient recycling appears more important to the outcome of bio-manipulation than grazing impacts. Macrophyte harvesting unexpectedly decreased phytoplankton biomass linked to declines in Euglenophyta and diatoms (Asterionella spp.). Cyanophyta (Oscillatoriales spp./Anabaena spp.) increased in response to macrophyte harvesting and was consistent with findings on European lakes that Cyanophyta abundance tends to be higher in the absence of macrophytes. Results indicate exotic fish removal, nutrient loading control and macrophyte conservation is important in these aquatic systems to maintain high water quality.     

分级进水对阶梯垂直流人工湿地污水处理效果的影响

本文研究了分级进水对阶梯垂直流人工湿地处理生活污水效果的影响.在保持总水力负荷为100 mm/d的情况下,分别将总进水量的0%、10%、20%和30%用于湿地第2级阶梯的进水,分析了系统对化学需氧量(COD)和氮、磷的总去除率和沿程变化.结果表明,不同分级进水比例条件下人工湿地对COD和总磷(TP)的去除率差异不明显,COD和TP的最高去除率分别为87.80%和81.17%,COD的去除主要集中在第1级,其贡献率平均为82.18%,TP的去除主要集中在第3级,贡献率平均为54.37%.分级进水对总氮(TN)去除率影响显著(P0.05),当2级进水比例为20%时,TN去除率最高,为61.70%±4.48%,且3个梯级对TN的去除贡献率分别为36.52%、42.11%和21.37%.相同组合形式的垂直流人工湿地处理生活污水的工程应用中,可根据需求设置20%左右的2级进水比例,以提高人工湿地对污染物的去除效果.     

Perfluorinated compounds in surficial sediments of the Ganges River and adjacent Sundarban mangrove wetland,India

This study reports the first evidence of the quantification of two dominant perfluorinated compounds (PFCs), namely perfluorooctanesulfate (PFOS) and perfluorooctannoate (PFOA), in surface sediment samples (0–5 cm; n = 13) from the Ganges (Hugli) River including Sundarban wetland, India using HPLC–MS/MS. The concentrations of PFOA exhibited a wide range of concentrations from <0.5 to 14.09 ng/g dry wt, whereas the concentration of PFOS was always below the detection limit of <0.5 ng/g dry wt. A consistent enrichment of PFOA was recorded in all the five sites of Sundarban (mean value 11.61 ± 1.86) whereas it was of moderate concentration or below the detection level in the seven sites along with the lower stretch of the Ganges (Hugli) River estuary (mean value 5.96 ng/g dry wt ± 5.36). Wastewater and untreated effluents are likely the major causes of accumulation of PFCs in sediments. The present paper could be used as baseline study to assess future monitoring programs of the ecosystem.     

Amelioration of marine farming impact on the benthic environment using artificial reefs as biofilters

An in situ monitoring of the sediment characteristics and macrobenthic communities was undertaken at a marine fish culture site in subtropical waters of Hong Kong before and after the deployment of biofilters which were made of cement concrete artificial reef (AR) structures. According to the distance to the boundary of the fish cages, 6 points were selected as sampling stations: 2 at the fish cages, 2 near the boundary of the fish culture area, and 2 reference sites further away from the culture area. Bimonthly sediment samples were collected for analysis of silt-clay fraction (SCF), moisture content (MC), total organic carbon (TOC), total Kjeldahl nitrogen (TKN) and total phosphorus (TP). The macrobenthos (>0.5 mm) present in the sediment were sorted, identified and enumerated. TOC, TKN and TP levels at the fish cage stations were consistently higher than those at the reference stations over the 1-year pre-AR and 2-year post-AR deployment monitoring period. The diversity of macrofauna was significantly reduced at the fish cage stations relative to the reference sites. The intermediary stations near the fish culture area showed a transitional state of disturbance. Over the 2-year post-AR deployment period, TOC, TKN and TP showed a decreasing trend at the fish cage and intermediary stations. More diverse macrofaunal communities were recorded at the fish cage stations, with species diversity H′increasing from 0–1 at the beginning of the AR deployment to H′ > 2 at the end of the study. The present results demonstrated that artificial reefs can improve the benthic abiotic environment and biotic conditions beneath fish rafts which are deteriorated due to farming activities.     

城市湖泊水环境修复组合工艺效果研究——以深圳市荔枝湖治理工程为例

以深圳市荔枝湖为例,通过历时9个月的水质连续监测,研究该湖水污染综合治理工程实施后不同治理工艺的处理效果.研究表明,自动过滤工艺TP和COD平均去除率分别为33.6%和16.2%;生物砾石床工艺TP和COD平均去除率分别为39.O%和21.3%;人工湿地工艺TP和COD平均去除率分别为80.2%和56.1%.通过荔枝湖四湖总磷串联模型,计算在设计初始条件下,采用组合治理工艺时湖水恢复为地表Ⅳ类水所需要的时间.计算表明工艺每天运行24h,需要2.5d可将各湖TP浓度降至O.1mg/L以下,TP总去除量为7.27kg,去除率为46.%.     

Effects of turbulence motion on the growth and physiology of aquatic plants

Growth, stem morphology and some biochemical parameters were studied of one completely submerged (Myriophyllum spicatum) and two floating leaved macrophytes (Nymphoides peltata and Trapa japonica) under different turbulence velocities. The root mean square velocities of the high, medium and low amount of turbulence that was generated for the experiment were 2.18 ± 0.66, 1.48 ± 0.26 and 0.70 ± 0.07 cm s⁻¹, respectively, in the microcosm. All three experimental plants survived exposed to all turbulence conditions provided, although a decrease in shoot elongation rate was associated with an increase in turbulence. Acceleration of tissue H₂O₂ generation and MDA content increased during the study period in all plant species. Oxidative enzymatic activities (POD, IAA and CKX) increased with time in plants under medium and high turbulence velocities. The shoot elongation rate, stem and leaf diameter, chlorophyll content and carbohydrate fractionations were found to be affected by this abiotic stress. It is evident from this study that high turbulence velocity inhibits normal metabolic activities of all three plants, while low to medium turbulence does not harm the floating leaved plants. Moreover, floating leaved plants were found to possess highly capable strategies to cope with this mechanical stress than completely submerged species.     

Identifying the relationships between trophic states and their driving factors in the Shihmen Reservoir,Taiwan

Eutrophication has become a crucial issue for water resource management in recent years. In addition, reservoir trophic states are varied with environmental and water quality variables. The objectives of this study were to apply the DFA model to examine which water quality variables significantly affect variations of trophic state index (TSI) factors (i.e. total phosphorus (TP), chlorophyll-a (Chl-a), and Secchi disk transparency (SD)) and use classification and regression tree (CART) to determine the trophic states of the Shinmen Reservoir based on the levels of TSI factors during spring 2001–winter 2009. Results showed that the optimal DFA model contained one common trend (the underlying processes influencing trophic states, which can be rainfall intensity or runoff volume) and 7 explanatory variables. Turbidity (TB), pH, and dissolved oxygen (DO) influence concentrations of TP, while ammonium nitrogen (NH₃-N), organic nitrogen (O-N), and nitrate nitrogen (NO₃-N) control variations of Chl-a, and TB is related to SD. The CART model can specify trophic states only using two dominant driving factors, i.e. TP and Chl-a. The results of the CART illustrated that eutrophication could be occurred in the Shihmen Reservoir if TP is greater than 31.65 μg/L or if Chl-a is greater than 5.95 μg/L while TP concentration is less than 31.65 μg/L. Runoff nonpoint source pollution resulted from heavy storms may be the important factor affecting reservoir trophic states. Establishing vegetative filter strips along the riparian zone may able to effectively reduce this pollution in a reservoir. The integrated DFA and CART serves as good-fit relationships among trophic states, TSI factors, and water quality variables and provide control strategies for managing water quality in the Shihmen Reservoir.     

Multiple extreme environmental conditions of intermittent soda pans in the Carpathian Basin (Central Europe)

Soda lakes and pans represent saline ecosystems with unique chemical composition, occurring on all continents. The purpose of this study was to identify and characterise the main environmental gradients and trophic state that prevail in the soda pans (n = 84) of the Carpathian Basin in Central Europe. Underwater light conditions, dissolved organic matter, phosphorus and chlorophyll a were investigated in 84 pans during 2009–2010. Besides, water temperature was measured hourly with an automatic sensor throughout one year in a selected pan. The pans were very shallow (median depth: 15 cm), and their extremely high turbidity (Secchi depth median: 3 cm, min: 0.5 cm) was caused by high concentrations of inorganic suspended solids (median: 0.4 g L⁻¹, max: 16 g L⁻¹), which was the dominant (>50%) contributing factor to the vertical attenuation coefficient in 67 pans (80%). All pans were polyhumic (median DOC: 47 mg L⁻¹), and total phosphorus concentration was also extremely high (median: 2 mg L⁻¹, max: 32 mg L⁻¹). The daily water temperature maximum (44 °C) and fluctuation maximum (28 °C) were extremely high during summertime. The combination of environmental boundaries: shallowness, daily water temperature fluctuation, intermittent hydroperiod, high turbidity, polyhumic organic carbon concentration, high alkalinity and hypertrophy represent a unique extreme aquatic ecosystem.     

湖泊湿地的水质净化效应——以太湖三山湿地为例

为了解湖泊湿地的水质净化效果,以太湖三山湿地为研究对象,综合利用遥感、GIS技术、现场水质监测、实验室分析和模型模拟等方法,分析三山湿地对污染物的拦截净化效果,进而探讨湖泊湿地对水体氮、磷污染物的削减渠道及其贡献率.结果表明三山湿地对太湖水体和三山岛生活污水均有明显净化效果.2014年三山湿地的总氮(TN)、总磷(TP)输入通量分别为549.45和19.4 t,通过水草打捞/收割分别去除20.99和4.52 t,湿地水体内TN、TP变化量分别为528.46和14.88 t,这部分营养盐输出途径包括沉积到底泥、降解转化、水体交换等.湿地的TN、TP拦截能力分别为2723.56和102.48 kg/(hm2·a).水生植物收割打捞与底泥疏浚是提高湿地水质净化能力的有效措施.水动力模拟结果显示,三山湿地建成后使附近水域水体流向发生变化,流速减小,对湿地内水质产生多方面的作用.     

Removal and biodegradation of nonylphenol by different Chlorella species

All four Chlorella species, including one commercially available species, Chlorella vulgaris and three local isolates, Chlorella sp. (1uoai), Chlorella sp. (2f5aia) and Chlorella miniata (WW1), had a rapid and high ability to remove nonylphenol (NP). Among these species, C. vulgaris had the highest NP removal (nearly all NP was removed from the medium) and degradation abilities (more than 80% of NP was degraded) after 168 h, followed by WW1 and 1uoai; 2f5aia had the lowest NP degradation ability. The NP removal by C. vulgaris was less affected by growth conditions, but its biodegradation efficiency was significantly increased by temperature and light intensity, suggesting that the biodegradation ability was positively related to photosynthetic and metabolic activities. These results indicated that C. vulgaris was the most suitable species for effective removal and biodegradation of NP, especially under 25 °C with light illumination and initial biomass between 0.5 and 1.0 mg chlorophyll l⁻¹.     

Water quality parameters response to temperature change in small shallow lakes

Effects of temperature (T) on water quality of three small shallow lakes in Taihu Lake region of China were investigated. The annual temperature was classified into three levels: low temperature (LT, 4 °C < T ⩽ 10 °C), middle temperature (MT, 10 °C < T ⩽ 20 °C), and high temperature (HT, 20 °C < T ⩽ 30 °C). Results showed that total nitrogen (TN) and total phosphorus (TP) concentrations might go to a fixed value (or range) in small shallow lakes receiving domestic sewage and farm drainage water. Nitrogen concentrations in the lakes were mainly in the form of nitrate (${\text{NO}}_3^{-}$) at above concerned three temperature levels, and nitrogen concentrations in the forms of TN, TIN, and ${\text{NO}}_3^{-}$ were increased with the increase of nutrient input. At the LT and MT levels, there was a series of good cubic curve relationships between temperatures and three N forms (TN, ${\text{NO}}_3^{-}$ and ${\text{NH}}_4^{+}$). The temperatural inflexion change points in the curves were nearly at 7 °C and 14 °C, respectively. However, no significant relationship between temperature and any water quality parameter was observed at the HT level. The significant relationship of TIN to TN, ${\text{NO}}_3^{-}$ to TN and ${\text{NH}}_4^{+}$ to dissolve oxygen (DO) was exist in three temperature portions, and TP to Chemical oxygen demand (COD, determined by potassium permanganate oxidation methods) in LT and MT, TP to pH or DO in HT also exist. COD were less than 6 mg L⁻¹ at each temperature level, and pH values were the largest in HT than it in LT or MT. Thus, changes between temperature and water quality parameters (TN, ${\text{NO}}_3^{-}$, ${\text{NH}}_4^{+}$ and TP) obviously nearly in 7 °C or 14 °C in lakes show that water self-purification of natural small shallow lakes were obviously with temperature changed.     

Removal of heavy metals from contaminated water using ethylenediamine-modified green seaweed (Caulerpa serrulata)

The demand for clean water is on the increase as the population increases. One of the ways to address the water shortage is to treat the polluted water through removal of the contaminants. The use of adsorbents for pollutant removal is one of the promising methods. Seaweed is an aquatic plant and its sorption ability for selected metals in water was investigated in this study. We report the performance of the seaweed (Caulerpa serrulata) before and after modification with ethylenediamine (EDA), on adsorption of copper, lead and cadmium in aqueous solution. The adsorption capacities for Cu, Cd and Pb were 5.27 mg g⁻¹, 2.12 mg g⁻¹ and 2.16 mg g⁻¹, respectively, with the EDA-modified seaweed, and 3.29 mg g⁻¹, 4.57 mg g⁻¹ and 1.06 mg g⁻¹, with the unmodified weed, respectively. The pH for maximum adsorption was found to be within the range of pH 4–pH 6. In a separate investigation, it was found that 0.1 g of dried seaweed leached 20 mg of dissolved organic carbon (DOC) using 100 ml of distilled-deionised water. The resulting solution was green. The leaching phenomenon contributes to secondary pollution. Modification of the seaweed with EDA reduced the DOC content by half (50%) and also removed the green colouration. Kinetic studies showed that the adsorbent was able to take up to 95% of the metals (in synthetic standard solutions) in less than 10 min. The adsorbed metals were then stripped using a solution of 0.5 M HNO₃ indicating that the adsorbent can be regenerated. In addition, the study revealed that modification improved the thermal stability of the adsorbent such that even when the temperature was raised to 1000 °C, more than 80% (compared to <50% for unmodified weed) of the modified adsorbent was not degraded, indicating that modification had a significant influence on the thermal stability of seaweed. The modified seaweed has been shown to have great potential for the removal of metals and DOC in polluted water. The modified adsorbent can therefore be applied for the removal of metals in polluted waters hence suitable for treatment of water for domestic consumption at a point of use.     

人工湿地复合基质深度净水除磷实验

通过垂直上升流人工湿地模拟柱实验,研究了泥炭、蛭石、砾石以不同体积比(柱1比例1:1:3,柱2比例1:1:2, 柱3比例1:1:1,柱4全为砾石)组成的复合基质对人工湿地出水的深度除磷效果．结果表明,填充复合基质的柱1-3对总磷和正磷酸盐的处理效果较好,去除率分别达到了77％和90％以上,明显优于填充单一基质砾石的柱4(27％和 21％);蛭石、泥炭价格远高于砾石,从经济、有效的原则出发,用蛭石、泥炭、砾石以1:1:3的体积比例混合作为复合填料比较合理;该复合基质适合于水质深度净化,在进水总磷浓度不超过0．1 mg／L的情况下,除磷效果相当稳定,可以保证 0．02mg／L以下的出水浓度(地表Ⅲ类水质标准),并达到80％左右的去除率;遇到高浓度磷污染负荷冲击时,磷去除率会降低;该复合基质的除磷机制主要为吸附净化,单独使用易吸附饱和,而与人工湿地中与湿地植物的吸收净化衔接起来,就能形成稳定持久的除磷效果．     

A comparative study of toxicity identification using Daphnia magna and Tigriopus japonicus: Implications of establishing effluent discharge limits in Korea

In Korea, the new permission criteria for industrial effluents based on Daphnia magna acute toxicity tests will be gradually implemented starting from 2011. Thus, in this study, toxicity assessment and identification using a marine species (Tigriopus japonicus) and the freshwater species (D. magna) was comparatively investigated. Effluent from an acid mine drainage treatment plant showed acute toxicity toward both organisms due to low pH, which was removed by neutralization of the effluent. Additionally, evaluation of the effluent of an electronics company revealed that Cu was attributable to the observed toxicity, and the effluent was more toxic toward T. japonicus than D. magna. Moreover, effluents from a metal plating factory were acutely toxic toward D. magna (6.50 TU), while they were not toxic against T. japonicus. Toxicity identification revealed that the high level of Cl⁻ (12,841 mg L⁻¹) was the cause of toxicity. Thus, the effluents had no effect on the marine species, T. japonicus. These findings suggest that a marine species rather than a freshwater species is more desirable for toxicity assessment of industrial effluent discharged into the saltwater, and thus should be considered in the legislation of toxicity-based discharge limits in Korea.     

Seasonal and vertical distributional patterns of siphonophores and medusae in the Chiloé Interior Sea,Chile

The horizontal and vertical distribution of jellyfish was assessed in the Chiloé Inland sea, in the northern area of the Chilean Patagonia. A total of 41 species of cnidarians (8 siphonophores, 31 hydromedusae, 2 scyphomedusae) were collected. Eleven jellyfish species were recorded for the first time in the area. Species richness was higher in spring than in winter (37 vs. 25 species, respectively). Species such as Muggiaea atlantica, Solmundella bitentaculata, and Clytia simplex were extremely abundant in spring. The total abundance (408,157 ind 1000 m^?3) was 18 times higher in spring than in winter (22,406 ind 1000 m^?3).The horizontal distribution of the most abundant species (four in winter, five in spring) showed decreasing abundances in the north–south direction in winter and spring. Peak abundances occurred in the northern microbasins (Reloncaví Fjord, Reloncaví and Ancud gulfs), where the water column stability, phytoplankton and zooplankton abundance were higher, compared with the southern microbasins (Corcovado Gulf, Boca del Guafo). During the spring higher jellyfish abundance season, the vertical distribution of the dominant species (except M. atlantica) showed peak values at mid-depth (30–50 m) and in the deepest sampled layer (50–200 m). This vertical distribution pattern reduced seaward transport in the shallowest layer through estuarine circulation and also limited mortality by predation in the more illuminated shallow layers. Thus, jellyfish were able to remain in the interior waters during the season of maximum biological production.     

The dynamics of Chaoborus americanus in an Adirondack lake following the reintroduction of fish

Acid deposition during the 20th century led to the gradual elimination of fish in Brooktrout Lake (Adirondack Mountains, New York State). Thereafter, the lake was colonized by Chaoborus americanus, a dipteran with an aquatic larval stage that typically resides in the pelagic zone in fishless lakes. During subsequent chemical recovery from acidification, the lake was stocked with Brook Trout (Salvelinus fontinalis). For seven years following this reintroduction we examined the re-adaptation of the food chain. The C. americanus abundance and distribution was quantified utilizing a combination of hydroacoustics, traditional vertical net tows and Schindler-Patalas trap collections. Hydroacoustic backscattering signals were repeatable and correlated (r = 0.86, p = 0.003) with C. americanus abundance. Backscattering, depth, month and year were used to develop a random forest model that predicted the C. americanus density (r² = 0.67,  p< 0.05). The hydroacoustic signal revealed a clear but limited diurnal vertical migration of C. americanus. The signal continued in the presence of the fish population beginning with reintroduction in 2005 and extending through 2011. In 2012, the hydroacoustic signal no longer was present in the lake, suggesting that the fish had eliminated the C. americanus population, which was verified with net tows. Using novel and traditional survey methods, we demonstrate that the reintroduction of fish can alter the lake community structure significantly through the extirpation of the major component of the pelagic zone.