Aquaculture impacts on the algal and bacterial communities in a small boreal forest lakeThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1936-1948 ◽  
Author(s):  
David L. Findlay ◽  
Cheryl L. Podemski ◽  
Susan E.M. Kasian
Keyword(s):  
Water Quality ◽  
Nutrient Loading ◽  
Stocking Density ◽  
Freshwater Ecosystem ◽  
Experimental Lakes Area ◽  
Fish Food ◽  
Total N ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
The Impact

A whole-lake experiment to examine the impacts of aquaculture on a freshwater ecosystem was conducted at the Experimental Lakes Area in northwestern Ontario, Canada. From 2003 to 2006, a 10 tonne fish capacity aquaculture cage stocked with rainbow trout ( Oncorhynchus mykiss ) was operated in Lake 375 and the impact of excess nutrients on the algal and bacteria communities was examined. The experiment was designed as a nutrient loading experiment with fish food and fish excretion the source of nutrients. Total N and P concentrations increased over the 4 years (15× and 4×, respectively). Phytoplankton biomass increased 4× annually following the start of aquaculture operation in 2003. The most dramatic responses occurred during spring and fall mixing, with blooms of chrysophytes and dinoflagellates increasing biomass by up to 12×. Bacteria biomass and densities were unaffected except for increases in late fall. Periphyton biomass was relatively unaffected except for an increase in biomass in the fourth year. The combination of a long water residence time in the lake coupled with an extremely high fish stocking density in Lake 375 resulted in an immediate impact on water quality. The results suggest that the impacts of aquaculture are accumulative and continual stocking will further impact water quality.

Water Quality Effects from an Aquaculture Operation in a Meromictic Iron Pit Lake in Northwestern Ontario, Canada

2010 ◽  
Vol 45 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Kimberly A. McNaughton ◽  
Peter F. Lee
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Nutrient Loading ◽  
Dissolved Inorganic Carbon ◽  
Fish Farm ◽  
Pit Lake ◽  
Fish Food ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
Iron Mine

Abstract In 1989, aquaculture for the production of rainbow trout (Oncorhynchus mykiss) was started in the upper depths of the 180-m deep Caland pit lake formed after the flooding of the former Steeprock Iron Mine. After ten years of operation, water quality was shown to be affected by the fish farm as well as proximal waste and the surficial geology of the area. Meromictic conditions occurred in the pit lake with a dichotomy in water quality versus depth. A cluster of parameters (ammonia, total phosphorus, total Kjeldahl nitrogen, dissolved organic carbon, B, pH, dissolved oxygen) were either in higher concentrations in the mixolimnion or varied little throughout the entire water column, and a second cluster of parameters had higher levels below the chemocline (conductivity, alkalinity, dissolved inorganic carbon, total dissolved solids, nitrate, sulfate, Ca, Mg, hardness, Na, Cl, K, Fe, Mn, Sr, and silicon dioxide). Statistically significant variations in concentrations among many of these chemical parameters were observed between the two years of study, among depths, and among seasons. Nutrient loading from excess fish food and waste increased phosphorus and ammonia levels. The expansion of the fish farm also reduced the levels of dissolved oxygen in the lower depths of the pit lake, thus reducing the volume of usable water for aquaculture purposes. In the early 2000s the fish farm decreased production and those closed in 2006. Later data showed that nitrate and potassium had corresponding decreases in both the monimolimnion and the mixolimnion. Sulfate levels remained elevated.

Predicting change in biogeochemical potential of subsurface systems with changing hydrogeological conditions

2021 ◽  
Author(s):  
Swamini Khurana ◽  
Falk Heße ◽  
Martin Thullner
Keyword(s):  
Water Quality ◽  
Preferential Flow ◽  
Nutrient Loading ◽  
Temporal Dynamics ◽  
Reaction Network ◽  
Climate Scenario ◽  
Ecosystem Functions ◽  
External Forcing ◽  
Spatio Temporal ◽  
The Impact

<p>In a changing climate scenario, we expect weather event patterns to change, both in frequency and in intensity. The subsequent impacts of these changing patterns on ecosystem functions are of great interest. Water quality particularly is critical due to public health concerns. Already, seasonal variation of water quality has been attributed to varying microbial community assemblages and nutrient loading in the corresponding water body but the contribution of the variations in the quantity of groundwater recharge is a missing link. It is thus beneficial to establish links between external forcing such as changing infiltration rate or recharge on nutrient cycling in the subsurface. We undertake this study to investigate the impact of temporal variation in external forcing on the biogeochemical potential of spatially heterogeneous subsurface systems using a numerical modeling approach. We used geostatistical tools to generate spatial random fields by considering difference combinations of the variance in the log conductivity field and the anisotropy of the domain. Tuning these two parameters assists in effective representation of a wide variety of geologic materials with varying intensity of preferential flow paths in the heterogeneous domain. We ran simulations using OGS#BRNS that enables us to combine a flexibly defined microbial mediated reaction network with the mentioned spatially heterogeneous domains in transient conditions. We propose that a combination of estimated field indicators of Damköhler number, Peclet number (transformed Damköhler number: Da<sub>t</sub>), and projected temporal dynamics in surface conditions can assist us in predicting the change in biogeochemical potential of the subsurface system. Preliminary results indicate that we miss potentially critical variations in reactive species concentration if we neglect spatio-temporal heterogeneities for regimes where 1<Da<sub>t</sub><40. For regimes characterized by values outside this range, we propose that spatio-temporal heterogeneities due to subsurface structure and changing hydrological forcing may not be relevant.</p>

The impact of stocking density on the welfare of rainbow trout (Oncorhynchus mykiss)

Aquaculture ◽  
2006 ◽  
Vol 255 (1-4) ◽  
pp. 466-479 ◽  
Author(s):  
B.P. North ◽  
J.F. Turnbull ◽  
T. Ellis ◽  
M.J. Porter ◽  
H. Migaud ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Stocking Density ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
The Impact

scholarly journals Remediation of Nitrogen and Phosphorus from Nursery Runoff during the Spring via Free Water Surface Constructed Wetlands

2010 ◽  
Vol 28 (4) ◽  
pp. 209-217 ◽  
Author(s):  
Sarah A. White ◽  
Milton D. Taylor ◽  
Stewart L. Chandler ◽  
Ted Whitwell ◽  
Stephen J. Klaine
Keyword(s):  
Water Quality ◽  
Water Surface ◽  
Nutrient Loading ◽  
Free Water ◽  
Surface Water Quality ◽  
Phosphorus Loading ◽  
Late Winter ◽  
Nitrogen And Phosphorus ◽  
Free Water Surface ◽  
The Impact

Abstract Agricultural operations face increasing pressure to remediate runoff to reduce deterioration of surface water quality. Some nursery operations use free water surface constructed wetland systems (CWSs) to remediate nutrient-rich runoff. Our objectives were twofold, first to examine the impact of two hydraulic retention times (HRT, 3.5 and 5.5 day) on CWS performance, and second to determine if increased nutrient loading from internal CWS and nursery sources during the spring contributed to nutrient export in excess of regulatory limits. We quantified nutrient loading and removal efficiency in a free water surface CWS from late winter through late spring over three years and monitored various water quality parameters. Total nitrogen in runoff was reduced from 20.6 ± 2.8 mg·liter−1 (ppm) to 4.1 ± 1.3 mg·liter−1 (ppm) nitrogen after CWS treatment. Phosphorus dynamics in the CWS were more variable and unlike nitrogen dynamics were not consistently influenced by water temperature and hydraulic loading rate. Phosphorus concentrations were reduced from 1.7 ± 0.8 mg·liter−1 (ppm) PO4-P in influent to 1.2 ± 0.6 mg·liter−1 (ppm) PO4-P in CWS effluent, but substantial variability existed among years in both phosphorus loading and removal rates. The CWS was able to efficiently remediate nitrogen even under high spring loading rates.

scholarly journals Assessment of the Impact of Land Cover Type on the Water Quality in Lake Tondano Using a SWAT Model

2021 ◽  
Vol 56 (1) ◽  
Author(s):  
Moh Sholichin ◽  
Tri Budi Prayogo
Keyword(s):  
Water Quality ◽  
Land Cover ◽  
Agricultural Land ◽  
Assessment Tool ◽  
Swat Model ◽  
Coefficient Of Determination ◽  
Organic N ◽  
Lake Water Quality ◽  
Total N ◽  
The Impact

Lake Tondano is the largest natural lake in North Sulawesi, Indonesia, which functions as a provider of clean water, hydroelectric power, rice field irrigation, inland fisheries, and tourism. This research aims to determine the effect of land cover types from the Tondano watershed on the lake water quality. The Soil and Water Assessment Tool (SWAT) model was used to evaluate the rate of soil erosion and the pollutant load of various land types in the watershed during the last ten years. Rainfall data is obtained from two rainfall stations, namely Paleloan Station and Noonan Station. The model is calibrated and validated before being used for analysis. We use climatological data from 2014 to 2019. The process of the SWAT model calibration and validation was carried out with the statistical formulas of the coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE). The results show that the potential for pollution load from the Tondao watershed is organic N of 0.039 kg/ha and organic P of 0.006 kg/ha coming from the agricultural land. The results of this study conclude that the fertility conditions of Lake Tondano are at the eutrophic level, where the pollutant inflow is collected in the lake waters, especially for the parameters of total N (1503697.44kg/year) and total P (144831.36kg/year). The SWAT simulation results show deviation between the modeling and field data collected with the value of R2 = 0.9303, and the significant level ≤ 10.

scholarly journals Modelling microbiological water quality in the Seine river drainage network: past, present and future situations

2007 ◽  
Vol 11 (5) ◽  
pp. 1581-1592 ◽  
Author(s):  
P. Servais ◽  
G. Billen ◽  
A. Goncalves ◽  
T. Garcia-Armisen
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Nutrient Loading ◽  
Large River ◽  
Population Increase ◽  
Wastewater Management ◽  
Drainage Network ◽  
Seine River ◽  
Microbiological Water Quality ◽  
The Impact

Abstract. The Seine river watershed is characterized by a high population density and intense agricultural activities. Data show low microbiological water quality in the main rivers (Seine, Marne, Oise) of the watershed. Today, there is an increasing pressure from different social groups to restore microbiological water quality in order to both increase the safety of drinking water production and to restore the possible use of these rivers for bathing and rowing activities, as they were in the past. A model, appended to the hydro-ecological SENEQUE/Riverstrahler model describing the functioning of large river systems, was developed to describe the dynamics of faecal coliforms (FC), the most usual faecal contamination indicator. The model is able to calculate the distribution of FC concentrations in the whole drainage network resulting from land use and wastewater management in the watershed. The model was validated by comparing calculated FC concentrations with available field data for some well-documented situations in different river stretches of the Seine drainage network. Once validated, the model was used to test various predictive scenarios, as, for example, the impact of the modifications in wastewater treatment planned at the 2012 horizon in the Seine watershed in the scope of the implementation of the european water framework directive. The model was also used to investigate past situations. In particular, the variations of the microbiological water quality in the Parisian area due to population increase and modifications in wastewater management were estimated over the last century. It was shown that the present standards for bathing and other aquatic recreational activities are not met in the large tributaries upstream from Paris since the middle of the 1950's, and at least since the middle of the XIXth century in the main branch of the Seine river downstream from Paris. Efforts carried out for improving urban wastewater treatment in terms or organic matter and nutrient loading resulted in a sensible reduction of microbiological contamination, but were not specific enough toward bacteriological contamination for achieving the objective of restoring levels compatible with bathing activities in the Parisian area.

Calculation and Analysis of Water Quality Improvement Caused by Water Diversion in Nanjing Qinhuai River

2012 ◽  
Vol 256-259 ◽  
pp. 2528-2532
Author(s):  
Chao Feng Tong ◽  
Li Rui Lv ◽  
Yu Yang Shao ◽  
Jia Ling Hao
Keyword(s):  
Water Quality ◽  
Nutrient Loading ◽  
Water System ◽  
Water Diversion ◽  
Middle Reach ◽  
Quality Model ◽  
One Dimensional ◽  
The Impact ◽  
Qinhuai River

To explore the impact of changes in water quality of the Nanjing Inner Qinhuai River water system in different water diversion way and to assess the transfer effect, an one-dimensional hydrodynamic and water quality model for Inner Qinhuai River was established to simulate and analysis the responds of water quality on the different nutrient loading and different diverted water. Four different water discharges diverted from Xuanwu Lake and Exterior Qinhuai River and two loads including the present load and 50% reduction were considered. The result shows the water quality can be improved significantly only as enough water is diverted and the sewage is intercept in the Middle Reach of the Inner Qinhuai River.

scholarly journals Nitrogen in Water-Portugal and Denmark: Two Contrasting Realities

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1114 ◽  
Author(s):  
Soraia Cruz ◽  
Cláudia M.d.S. Cordovil ◽  
Renata Pinto ◽  
António G. Brito ◽  
Maria R. Cameira ◽  
...  
Keyword(s):  
Water Quality ◽  
Surface Waters ◽  
Mineral Fertilizer ◽  
N Losses ◽  
Total N ◽  
Policy Responses ◽  
Mainland Portugal ◽  
Water Quality Status ◽  
Use Efficiency ◽  
The Impact

Agricultural activities are responsible for most of the nitrogen (N) inputs that degrade water quality. To elucidate the drivers leading to N pressures on water, we examined the resulting state of surface waters in terms of N concentrations, the impact of this on water quality status and policy responses to these constraints across different climatic and management conditions. Portugal and Denmark were chosen as contrasting case studies for the Driver-Pressure-State-Impact-Response (DPSIR) analysis. Our results showed reductions of 39% and 25% in the use of mineral fertilizer in Portugal and Denmark, respectively, between 2000 and 2010. The N surplus in Portugal varied between 15 and 30 kg N ha−1 between 1995 and 2015. In Denmark, in 2015, this amount was 70 kg N ha−1, representing a 53% decrease from the 1990 value. The average amount of total N discharged to surface waters was 7 kg ha−1 for mainland Portugal in 2015 and 14.6 kg ha−1 for Denmark in 2014. These reductions in the N surplus were attributed to historical policies aimed at N pressure abatement. In Denmark, N losses are expected to decline further through the continuation or improvement of existing national action plans. In Portugal, they are expected to decline further due to the expansion of Nitrate Vulnerable Zones and the introduction of targeted policies aimed at improving N use efficiency and reducing losses to water.

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