Experimental manipulations of the biomass of introduced carp (Cyprinus carpio) in billabongs. II. Impacts on benthic properties and processes1

1997 ◽  
Vol 48 (5) ◽  
pp. 445 ◽  
Author(s):  
A. I. Robertson ◽  
M. R. Healey ◽  
A. J. King
Keyword(s):  
Algal Biomass ◽  
Solid Phase ◽  
Negative Impact ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Sediment Surface ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
Biofilm Development ◽  
The Impact

Two billabongs on the floodplain of the Murrumbidgee River, Australia, were partitioned in half with impermeable plastic barriers and the biomass of carp was manipulated to establish high- and low-carp biomass treatments in each billabong. Measurements of benthic variables (rates of particle settlement, biofilm development, sediment respiration, macrophyte detritus decomposition, sediment solid-phase nutrient concentrations and benthic algal biomass) were performed over four months from summer to winter 1995. Rates of particle settlement were greater in the high-carp treatment of each billabong throughout the experiment. High carp biomass had a negative impact on the autotrophic component of the biofilm developing on wood blocks placed at different heights above the sediment surface but the mechanism responsible differed between billabongs. Sediment oxygen demand became greater in the presence of a higher biomass of carp during the experiment but time courses differed between billabongs. Manipulations of carp biomass did not influence algal biomass on the sediment surface, the rate of decomposition of macrophyte detritus or sediment solid-phase nutrients or nutrient ratios. The impact of carp on benthic and surficial processes was significant but the mechanisms of change differed between billabongs.

Considering the impact of intermittent discharges when modelling overflows

1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Preliminary Investigation ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Combined Sewer Overflows ◽  
River Hydraulics ◽  
Combined Sewer ◽  
The Impact ◽  
Curve Equation

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.

scholarly journals How to Choose Pollution Indicators for Monitoring Landfill Leachates

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 23
Author(s):  
Aleksandra Wdowczyk ◽  
Agata Szymańska-Pulikowska
Keyword(s):  
Negative Impact ◽  
Statistical Tests ◽  
Water Environment ◽  
Oxygen Demand ◽  
Principal Component ◽  
Ammonium Nitrogen ◽  
Landfill Leachates ◽  
Limit Of Quantification ◽  
Pollution Indicators ◽  
The Impact

Leachates are one of the main factors polluting the ground and water environment in the vicinity of landfills. This is connected with the need to systematically control the elements of the environment that are exposed to the negative impact of landfill emissions. In Poland, the scope of landfill leachate quality monitoring includes 10 obligatory parameters (pollution indicators). The paper presents an example of the application of selected statistical methods (basic statistics, statistical tests, principal component analysis) to assess the impact of individual pollution indicators on the quality of landfill leachates. Four landfills from the area of Lower Silesia were selected for analyzes, for which in the years 2018–2019 tests of leachate properties were conducted in an extended scope (in relation to the scope applicable during monitoring). Analyses of the obtained results showed significant differences between landfills, depending mainly on their age and method of operation. Specific factors for assessing differences between landfills were as follows: electrolytic conductivity, chemical oxygen demand (COD(Cr)), organic nitrogen, ammonium nitrogen, chlorides and calcium. The values of some of the parameters included in the monitoring studies did not show variability, remaining below the limit of quantification. The conducted analyses permit the determination of the level of leachate contamination from selected landfills and the proposal of indicators that could complement the monitoring range of landfills for many years.

scholarly journals Tourists increase the contribution of autochthonous carbon to littoral zone food webs in oligotrophic dune lakes

2004 ◽  
Vol 55 (7) ◽  
pp. 701 ◽  
Author(s):  
Wade L. Hadwen ◽  
Stuart E. Bunn
Keyword(s):  
Food Webs ◽  
Littoral Zone ◽  
Algal Biomass ◽  
Carbon Sources ◽  
Nutrient Concentrations ◽  
Relative Importance ◽  
Nutrient Inputs ◽  
Oligotrophic Lakes ◽  
Dune Lakes ◽  
The Impact

Tourists can adversely influence the ecology of oligotrophic lakes by increasing algal production via direct nutrient inputs and/or re-suspension of sediments. To assess the influence of tourists on food web dynamics, we used the natural abundance of stable isotopes of carbon and nitrogen to calculate the relative importance of autochthonous and allochthonous carbon sources to littoral zone food webs across five variously visited perched dune lakes on Fraser Island, Australia. The relative importance of autochthonous (phytoplankton and periphyton) carbon to littoral zone consumers was highly variable across taxa and lakes. Despite the potential influence of algal biomass, ambient nutrient concentrations and tannin concentrations on the contribution of autochthonous carbon to littoral zone food webs, none of these variables correlated to the per cent contribution of autochthonous carbon to consumer diets. Instead, autochthonous sources of carbon contributed more to the diets of aquatic consumers in heavily visited lakes than in less visited lakes, suggesting that tourist activities might drive these systems towards an increased reliance on autochthonous carbon. The assessment of the contribution of autochthonous carbon to littoral zone food webs may represent a more robust indicator of the impact of tourists in oligotrophic lakes than standard measures of nutrient concentrations and/or algal biomass.

scholarly journals A reactivity continuum of particulate organic matter in a global ocean biogeochemical model

2016 ◽  
Author(s):  
Olivier Aumont ◽  
Marco van Hulten ◽  
Matthieu Roy-Barman ◽  
Jean-Claude Dutay ◽  
Christian Ethé ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Critical Role ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Mesopelagic Zone ◽  
Ocean Biogeochemical Model ◽  
The Impact ◽  
Reactivity Continuum

Abstract. The marine biological carbon pump is dominated by the vertical transfer of Particulate Organic Carbon (POC) from the surface ocean to its interior. The efficiency of this transfer plays an important role in controlling the amount of atmospheric carbon that is sequestered in the ocean. Furthermore, the abundance and composition of POC is critical for the removal of numerous trace elements by scavenging, a number of which such as iron are essential for the growth of marine organisms, including phytoplankton. Observations and laboratory experiments have shown that POC is composed of numerous organic compounds that can have very different reactivities. Yet, this variable reactivity of POC has never been extensively considered, especially in modeling studies. Here, we introduced in the global ocean biogeochemical model NEMO-PISCES a description of the variable composition of POC based on the theoretical Reactivity Continuum Model proposed by (Boudreau and Ruddick, 1991). Our model experiments show that accounting for a variable lability of POC increases POC concentrations in the ocean’s interior by one to two orders of magnitude. This increase is mainly the consequence of a better preservation of small particles that sink slowly from the surface. Comparison with observations is significantly improved both in abundance and in size distribution. Furthermore, the amount of carbon that reaches the sediments is increased by more than a factor of two, which is in better agreement with global estimates of the sediment oxygen demand. The impact on the major macro-nutrients (nitrate and phosphate) remains modest. However, iron (Fe) distribution is strongly altered, especially in the upper mesopelagic zone as a result of more intense scavenging: Vertical gradients in Fe are milder in the upper ocean which appears to be closer to observations. Thus, our study shows that the variable lability of POC can play a critical role in the marine biogeochemical cycles which advocates for more dedicated in situ and laboratory experiments.

Monitoring Effects of Drought on Nitrogen and Phosphorus in Temperate Oak Forests Using Machine Learning Techniques

2018 ◽  
Author(s):  
Jan Kotlarz ◽  
Katarzyna Kubiak ◽  
Marcin Spiralski
Keyword(s):  
Machine Learning ◽  
Drought Stress ◽  
Negative Impact ◽  
Aerial Images ◽  
Machine Learning Techniques ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Learning Techniques ◽  
The Impact

Oak is a European tree species highly sensitive to drought. If declining symptoms appear they are often detectable at the crown (such as dieback) enabling monitoring using aerial images and remote sensing methods. Here, we analyzed the impact of short and long-term drought on oaks located in central Poland, between the years of 2014 and 2017. We used leaf nitrogen (N) and phosphorus (P) concentrations measured in the laboratory, aerial images collected in the range of 460-880 nm and machine learning techniques to estimate nutrient concentrations on the > 4000 oaks growing on gleysoil in the study area. We determined a negative impact on N and P concentrations during both types of drought stress (-23% and 19% for N concentration in leaves; -27% and -10% for P concentration in leaves) and an inconsiderable impact on N:P values (3% increase of N:P ration during short and 7% decrease of N:P ration during long-term drought stress). We found that the long-term drought impact was spatially diverse, possibly depending on the presence of drainage ditches and competing species.

scholarly journals Flow Regime and Nutrient-Loading Trends from the Largest South European Watersheds: Implications for the Productivity of Mediterranean and Black Sea’s Coastal Areas

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Stefano Cozzi ◽  
Carles Ibáñez ◽  
Luminita Lazar ◽  
Patrick Raimbault ◽  
Michele Giani
Keyword(s):  
Water Quality ◽  
Flow Regime ◽  
Nutrient Loading ◽  
Ecological Status ◽  
Coastal Areas ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
Runoff Series ◽  
River Loads ◽  
The Impact

In the last century, large watersheds in Southern Europe have been impacted by a combination of anthropogenic and climatic pressures, which have rapidly evolved to change the ecological status of freshwater and coastal systems. A comparative analysis was performed for Ebro, Rhône, Po and Danube rivers, to investigate if they exhibited differential dynamics in hydrology and water quality that can be linked to specific human and natural forces acting at sub-continental scales. Flow regime series were analyzed from daily to multi-decadal scales, considering frequency distributions, trends (Mann–Kendall and Sen tests) and discontinuities (SRSD Method). River loads of suspended matter, nutrients and organic matter and the eutrophication potential of river nutrients were estimated to assess the impact of river loads on adjacent coastal areas. The decline of freshwater resources largely impacted the Ebro watershed on annual (−0.139 km3 yr−1) and seasonal (−0.4% yr−1) scales. In the other rivers, only spring–summer showed significant decreases of the runoff coupled to an exacerbated flow variability (0.1–0.3% yr−1), which suggested the presence of an enhanced regional climatic instability. Discontinuities in annual runoff series (every 20–30 years) indicated a similar long-term evolution of Rhône and Po rivers, differently from Ebro and Danube. Higher nutrient concentrations in the Ebro and Po (+50%) compared to Rhône and Danube and distinct stoichiometric nutrient ratios may exert specific impacts on the growth of plankton biomass in coastal areas. The overall decline of inorganic phosphorus in the Rhône and Po (since the 1980s) and the Ebro and Danube (since the 1990s) mitigated the eutrophication in coastal ecosystems inducing, however, a phase in which the role of organic phosphorus loads (Po > Danube > Rhône > Ebro) on coastal productivity could be more relevant. Overall, the study showed that the largest South European watersheds are differently impacted by anthropogenic and climatic forces and that this will influence their vulnerability to future changes of flow regime and water quality.

Impact of proposed Glengowan Dam flow augmentation on Thames River water quality

1984 ◽  
Vol 11 (3) ◽  
pp. 459-473
Author(s):  
T. P. Halappa Gowda ◽  
R. J. Dewey
Keyword(s):  
Water Quality ◽  
River Water ◽  
Deterministic Model ◽  
Oxygen Demand ◽  
River Water Quality ◽  
Sediment Oxygen Demand ◽  
Treated Wastewater ◽  
Macrophyte Community ◽  
Thames River ◽  
The Impact

The Thames River water management study report, prepared in 1975 by the Ontario Ministries of Natural Resources and Environment, recommended the construction of the Glengowan Dam primarily for flow augmentation to improve the river water quality (Recommendation No. 1). As part of the environmental impact assessment of the proposed dam, detailed water quality prediction studies were carried out using deterministic and stochastic models to evaluate the impact of the proposed flow augmentation and wastewater loading options. The river receives treated wastewater effluents from five water pollution control plants (WPCP) in the study area, all located within the City of London. The processes simulated by the models include advection, decay of carbonaceous and nitrogenous oxygen demand (CBOD and NOD), sediment oxygen demand, atmospheric reaeration, and respiration and photosynthetic activity of aquatic macrophyte community. The options modelled include (a) projected CBOD and NOD loading rates from the five WPCP's for the planning period 1981–2001; (b) low flows attainable with augmentation from existing Fanshawe reservoir and the proposed Glengowan Dam; and (c) zero loadings to the Thames River from WPCP's, attainable with effluent bypassing to Lake Erie. The results of the modelling studies are presented in this paper. Key words: water quality, dissolved oxygen, flow augmentation, environmental assessment, Glengowan Dam, Thames River Basin, deterministic model, stochastic model.

scholarly journals Aquaculture Farming Effect on Benthic Respiration and Nutrient Flux in Semi-Enclosed Coastal Waters of Korea

2021 ◽  
Vol 9 (5) ◽  
pp. 554
Author(s):  
Sung-Han Kim ◽  
Jae-Seong Lee ◽  
Kyung-Tae Kim ◽  
Hyung-Chul Kim ◽  
Won-Chan Lee ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Control Factor ◽  
Fish Stock ◽  
Nutrient Fluxes ◽  
Oyster Farm ◽  
Benthic Nutrient Fluxes ◽  
Highly Correlated ◽  
The Impact

Sediment oxygen demand (SOD) and benthic nutrient fluxes (BNFs) were measured using an in situ benthic chamber at a fish farm (FF), oyster farm (OF), and controls (FF-C and OF-C) to assess the impact of aquaculture activities on organic carbon (OC) and nutrients cycles in coastal waters of Korea. The SOD at FF and OF ranged from 60 ± 2 to 157 ± 3 mmol m−2 d−1 and from 77 ± 14 to 84 ± 16 mmol m−2 d−1, respectively, more than five times those of the control sites. The SOD at farm sites is highly correlated with fish stock and food input, suggesting that excess feed input is an important control factor for OC remineralization. The combined analysis of sediment trap and SOD indicates that most of the deposited OC oxidized in the sediment and/or was laterally transported by the current before being buried in the sediment. The benthic nutrient fluxes at farms ranged from 5.45 to 8.95 mmol N m−2 d−1 for nitrogen and from 0.51 to 1.67 mmol P m−2 d−1 for phosphate, respectively, accounting for 37–270% and 52–804% of the N and P required for primary production in the water column. These results indicate that aquaculture farming may profoundly impact biogeochemical cycles in coastal waters.

scholarly journals Variable reactivity of particulate organic matter in a global ocean biogeochemical model

2017 ◽  
Vol 14 (9) ◽  
pp. 2321-2341 ◽  
Author(s):  
Olivier Aumont ◽  
Marco van Hulten ◽  
Matthieu Roy-Barman ◽  
Jean-Claude Dutay ◽  
Christian Éthé ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Critical Role ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Mesopelagic Zone ◽  
Modelling Studies ◽  
Ocean Biogeochemical Model ◽  
The Impact

Abstract. The marine biological carbon pump is dominated by the vertical transfer of particulate organic carbon (POC) from the surface ocean to its interior. The efficiency of this transfer plays an important role in controlling the amount of atmospheric carbon that is sequestered in the ocean. Furthermore, the abundance and composition of POC is critical for the removal of numerous trace elements by scavenging, a number of which, such as iron, are essential for the growth of marine organisms, including phytoplankton. Observations and laboratory experiments have shown that POC is composed of numerous organic compounds that can have very different reactivities. However, this variable reactivity of POC has never been extensively considered, especially in modelling studies. Here, we introduced in the global ocean biogeochemical model NEMO-PISCES a description of the variable composition of POC based on the theoretical reactivity continuum model proposed by Boudreau and Ruddick (1991). Our model experiments show that accounting for a variable lability of POC increases POC concentrations in the ocean's interior by 1 to 2 orders of magnitude. This increase is mainly the consequence of a better preservation of small particles that sink slowly from the surface. Comparison with observations is significantly improved both in abundance and in size distribution. Furthermore, the amount of carbon that reaches the sediments is increased by more than a factor of 2, which is in better agreement with global estimates of the sediment oxygen demand. The impact on the major macronutrients (nitrate and phosphate) remains modest. However, iron (Fe) distribution is strongly altered, especially in the upper mesopelagic zone as a result of more intense scavenging: vertical gradients in Fe are milder in the upper ocean, which appears to be closer to observations. Thus, our study shows that the variable lability of POC can play a critical role in the marine biogeochemical cycles which advocates for more dedicated in situ and laboratory experiments.

scholarly journals Investigating and Managing the Impact of Using Untreated Wastewater for Irrigation on the Groundwater Quality in Arid and Semi-Arid Regions

2021 ◽  
Vol 18 (14) ◽  
pp. 7485
Author(s):  
Hany F. Abd-Elhamid ◽  
Shaimaa M. Abd-Elmoneem ◽  
Gamal M. Abdelaal ◽  
Martina Zeleňáková ◽  
Zuzana Vranayova ◽  
...  
Keyword(s):  
Groundwater Quality ◽  
Negative Impact ◽  
Oxygen Demand ◽  
Treated Wastewater ◽  
Base Case ◽  
Untreated Wastewater ◽  
Pumping Rates ◽  
Recharge Rates ◽  
Wastewater Recharge ◽  
The Impact

This study aims to investigate the impact of using untreated wastewater in irrigation. Different scenarios of management were applied by mixing it with treated wastewater or freshwater on groundwater quality. A hypothetical case study is presented. The numerical model of MODFLOW is used in the simulation by applying four stages (21 scenarios) including: different values of pumping rates, changing wastewater recharge rates, and a combination of the previous scenarios. Additionally, protection scenario for groundwater was applied by using different values of mixing of freshwater with wastewater. The simulation was carried out for the contamination of Chemical Oxygen Demand COD and the concentration reached 48.6 ppm at a depth of 25 m and 19.41 ppm at a depth of 50 m in the base case. The results showed a negative impact on groundwater quality had occurred due to increasing the pumping rates, wastewater recharge rates, and combination between two scenarios, which led to an increase of the contaminants in the aquifers. However, positive protection effects occurred due to mixing the wastewater with treated wastewater. The results of COD concentration in groundwater using treated wastewater reached 81.82, 77.88, 74.03, 70.12, and 66.15 ppm at a depth of 25 m and 53.53, 50.95, 48.43, 45.87, and 43.28 ppm at a depth of 50 m, at concentrations of 93, 88.52, 84.14, 79.7, and 75.19 ppm with constant pumping and recharge rates of 4320 m3/d and 547.5 mm/year, respectively. The using of treated wastewater could improve the groundwater quality to be used in the irrigation process and help to minimize groundwater contamination. Moreover, the abstraction of the groundwater should be optimized, and the qualities of wastewater should be constrained in agriculture to protect the groundwater quality.

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