Water quality and phytoplankton dynamics in Moreton Bay, south-eastern Queensland. I. Field survey and satellite data

1998 ◽  
Vol 49 (3) ◽  
pp. 215 ◽  
Author(s):  
James McEwan ◽  
Albert J. Gabric ◽  
Peter R. F. Bell
Keyword(s):  
Water Quality ◽  
Nutrient Loading ◽  
Population Expansion ◽  
Water Clarity ◽  
Western Boundary ◽  
Nutrient Loads ◽  
Moreton Bay ◽  
South Eastern ◽  
Temporal And Spatial Variability ◽  
The Impact

The water quality of Moreton Bay, a sub-tropical estuarine embayment in south-eastern Queensland, was monitored over a 2-year period. Surveys in situ and ground-truthed satellite imagery were used to describe the temporal and spatial variability in water-quality indicators and the level of eutrophication. Strong east–west gradients in chlorophyll α and water clarity were found. During the study period fluvial discharges, which all enter on the western littoral, were below their long-term averages, and nutrient loading to the bay was dominated by point-source wastewater discharges along the western boundary. The data suggest that although the impact of nutrient loads on the bay’s eastern side is mitigated by tidal intrusion of oceanic water, the western areas are already degraded and can be considered mesotrophic to eutrophic. This part of the bay may deteriorate further with the projected future population expansion in the bay’s catchment.

Water quality and phytoplankton dynamics in Moreton Bay, south-eastern Queensland. II. Mathematical modelling.

1998 ◽  
Vol 49 (3) ◽  
pp. 227 ◽  
Author(s):  
James McEwan ◽  
Albert J. Gabric ◽  
Peter R. F. Bell
Keyword(s):  
Water Quality ◽  
Field Data ◽  
Nutrient Loading ◽  
Light Availability ◽  
Population Pressure ◽  
Eastern Region ◽  
Nutrient Loads ◽  
Quality Model ◽  
Moreton Bay ◽  
European Settlement

A coupled hydrodynamic water-quality model of Moreton Bay was developed to enable better management of nutrient loads and to predict eutrophication-related problems. The hydrodynamic submodel was calibrated to available tidal data, and the transport submodel was calibrated to a salinity dataset. A 15-month time-series of field data was used together with historical data to calibrate and validate the water-quality submodel. Model simulations suggest that denitrification removes over half the external N inputs with about one-third exported to the open ocean. Approximately 8% of N and 20% of the P loading accumulates in the sediments. Short-term variations due to hydrodynamic effects tend to mask the seasonal cycle in phytoplankton biomass except at inshore localities. The model predictions confirm the field data that indicate that water quality in the western bay is severely affected while the better flushed eastern region remains relatively unaffected. Future increases in nutrient loading due to population pressure are predicted to extend the severely affected region eastwards. Over most of the bay, algal productivity is N-limited except for the western margins where nutrients are saturating and light availability regulates growth. Model hindcasts suggest that system-wide mean algal production has increased by a factor of ten since European settlement.

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>

scholarly journals Assessment of Water Quality in Indo-Gangetic Plain of South-Eastern Asia under Organic vs. Conventional Rice Farming

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 960
Author(s):  
Debjani Sihi ◽  
Biswanath Dari ◽  
Zhengjuan Yan ◽  
Dinesh Kumar Sharma ◽  
Himanshu Pathak ◽  
...  
Keyword(s):  
Water Quality ◽  
Quality Parameters ◽  
Basmati Rice ◽  
Conventional Farming ◽  
Eastern Asia ◽  
Gangetic Plain ◽  
South Eastern ◽  
The Impact ◽  
Indo Gangetic Plain

Water contamination is often reported in agriculturally intensive areas such as the Indo-Gangetic Plain (IGP) in south-eastern Asia. We evaluated the impact of the organic and conventional farming of basmati rice on water quality during the rainy season (July to October) of 2011 and 2016 at Kaithal, Haryana, India. The study area comprised seven organic and seven conventional fields where organic farming has been practiced for more than two decades. Water quality parameters used for drinking (nitrate, NO3; total dissolved solids (TDS); electrical conductivity (EC) pH) and irrigation (sodium adsorption ratio (SAR) and residual sodium carbonate (RSC)) purposes were below permissible limits for all samples collected from organic fields and those from conventional fields over the long-term (~15 and ~20 years). Importantly, the magnitude of water NO3 contamination in conventional fields was approximately double that of organic fields, which is quite alarming and needs attention in future for farming practices in the IGP in south-eastern Asia.

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 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.

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.

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.

Mitigating Impacts of Natural Hazards on Fishery Ecosystems

2008 ◽  
Keyword(s):  
Water Quality ◽  
Nutrient Loading ◽  
Water Quality Management ◽  
River Estuary ◽  
Chemical Properties ◽  
Neuse River Estuary ◽  
Estuarine System ◽  
Nutrient Loads ◽  
Habitat Alterations ◽  
The Past

<em>Abstract</em>.—Since the mid-1990s, the U.S. mid-Atlantic region has witnessed a sudden rise in hurricane and tropical storm landfalls. In particular, eastern North Carolina has been impacted by eight hurricanes and six tropical storms in the past decade, and this relatively high frequency is forecast to continue for the next several decades. Each of the past storms exhibited unique hydrologic and nutrient loading scenarios for the Pamlico Sound, the United States’ second largest estuarine system and its largest subestuary, the Neuse River estuary. This variability represents a challenge to nutrient management aimed at protecting water quality and ensuring optimal fisheries habitat conditions. Different rainfall amounts among hurricanes led to variable freshwater and nutrient discharge and hence variable nutrient, organic matter, and sediment enrichment. These enrichments differentially affected physical and chemical properties (salinity, water residence time, transparency, stratification, dissolved oxygen), phytoplankton primary production, and phytoplankton community composition. The contrasting effects were accompanied by biogeochemical perturbations (hypoxia, enhanced nutrient cycling), benthic and planktonic habitat alterations, and possibly food web disturbances. Floodwaters from the two largest hurricanes, Fran (1996) and Floyd (1999), exerted multimonth to multiannual effects on hydrology, nutrient loads, productivity, biotic composition, and habitat condition. In contrast, relatively low rainfall coastal hurricanes like Isabel (2003) and Ophelia (2005) caused strong vertical mixing and storm surges but exhibited relatively minor hydrologic, nutrient, and biotic impacts. Both hydrologic and wind forcing are important drivers and must be integrated with nutrient loading in assessing short- and long-term ecological impacts of these storms. These climatic forcings cannot be managed but must be considered when developing water quality management strategies for these and other large estuarine ecosystems faced with increasing frequencies and intensities of hurricane activity.

scholarly journals Changes in land use in the buffer zone of lake of the Mała Wełna catchment

2012 ◽  
Vol 12 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Mariusz Ptak ◽  
Agnieszka E. Ławniczak
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Nutrient Loading ◽  
Lake Management ◽  
Buffer Zone ◽  
Nutrient Loads ◽  
Buffer Zones ◽  
Nutrient Sources ◽  
Forested Areas ◽  
Water Pollutant

Abstract One of the most important elements in the protection of water quality is buffer zones. In order to protect water quality, appropriate management of these areas is necessary. In the paper, changes in the land use in the buffer zone of 200 m width around lakes in the Mała Wełna catchment over 20 years were analysed. For the study eight lakes larger than 50 ha were chosen. Changes in the land use within the buffer zone were studied from 1980 to 2000, based on topographic maps in the scale 1:10 000. Results show both positive and negative aspects of land changes. An increase in forested areas and grasslands through tilled land were positive aspects of these changes. On the other hand, the enhancement of suburban development in these zones caused increased probability of water pollution from these areas. Calculations of potential nutrient loading from different types of land use in these zones indicated an enhancement of nutrient sources in the lakes within the 20-year study period. However, these changes are not significant in comparison to the nutrient loads contributed by the tributaries. Our study indicated that in the case of flow lakes, more important is an improvement in water quality in the tributaries and a reduction in nutrient sources in the catchment with the purpose of reducing the input of nutrients into the lake. Management of the buffer zone is one of the issues which have to be taken into consideration in lake protection after elimination of the major water pollutant sources.

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