Effects of Fe addition on sediment P dynamics in a eutrophic lake

2021 ◽  
Author(s):  
Melanie Münch ◽  
Rianne van Kaam ◽  
Karel As ◽  
Stefan Peiffer ◽  
Gerard ter Heerdt ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Surface Water ◽  
Water Column ◽  
Sediment Cores ◽  
Surface Water Quality ◽  
Water Interface ◽  
Eutrophic Lakes ◽  
Fe Addition

<p>The decline of surface water quality due to excess phosphorus (P) input is a global problem of increasing urgency. Finding sustainable measures to restore the surface water quality of eutrophic lakes with respect to P, other than by decreasing P inputs, remains a challenge. The addition of iron (Fe) salts has been shown to be effective in removing dissolved phosphate from the water column of eutrophic lakes. However, the resulting changes in biogeochemical processes in sediments as well as the long-term effects of Fe additions on P dynamics in both sediments and the water column are not well understood.</p><p>In this study, we assess the impact of past Fe additions on the sediment P biogeochemistry of Lake Terra Nova, a well-mixed shallow peat lake in the Netherlands. The Fe-treatment in 2010 efficiently reduced P release from the sediments to the surface waters for 6 years. Since then, the internal sediment P source in the lake has been increasing again with a growing trend over the years.</p><p>In 2020, we sampled sediments at three locations in Terra Nova, of which one received two times more Fe during treatment than the other two. Sediment cores from all sites were sectioned under oxygen-free conditions. Both the porewaters and sediments were analysed for their chemical composition, with sequential extractions providing insight into the sediment forms of P and Fe. Additional sediment cores were incubated under oxic and anoxic conditions and the respective fluxes of P and Fe across the sediment water interface were measured.</p><p>The results suggest that Fe and P dynamics in the lake sediments are strongly coupled. We also find that the P dynamics are sensitive to the amount of Fe supplied, even though enhanced burial of P in the sediment was not detected. The results of the sequential extraction procedure for P, which distinguishes P associated with humic acids and Fe oxides, as well as reduced flux of Fe(II) across the sediment water interface in the anoxic incubations, suggest a major role of organic matter in the interaction of Fe and P in these sediments.</p><p>Further research will include investigations of the role of organic matter and sulphur in determining the success of Fe-treatment in sequestering P in lake sediments. Based on these data in combination with reactive transport modelling we aim to constrain conditions for successful lake restoration through Fe addition.</p>

Characterization and variations of dissolved organic matter in the Lake Taihu area of China

2012 ◽  
Vol 12 (4) ◽  
pp. 439-450
Author(s):  
Yong Qiu ◽  
Hanchang Shi ◽  
He Jing ◽  
Rui Liu ◽  
Qiang Cai ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Surface Water ◽  
Dissolved Organic Matter ◽  
Lake Taihu ◽  
Surface Water Quality ◽  
Spatial Variations ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Seasonal And Spatial Variations

Lake Taihu in China is a eutrophicated lake surrounded by industrial and urbanized zones, thus its water quality often suffers from organic and nutrient contaminants. In this paper, a 1 year water quality survey was conducted around the lake and statistical analysis tools were used to characterize the variations of organic pollutants. Analysis of variance (ANOVA), cluster analysis and principal component analysis (PCA) confirm the seasonal and spatial variations of surface water quality in Lake Taihu. Surface water quality is better during the wet season and worse downstream during the dry season. The dissolved organic matter was further analyzed using a parallel factor analysis (PARAFAC) model with three-dimensional excitation-emission fluorescence matrices. Four components were extracted from the fluorescence data, namely, two autochthonous biodegradation products (C1: amino acids, C4: protein-like materials) and two humic-like substances (C2: from microbial processing, C3: terrestrial). C1 and C4 were dominant in the chromophoric dissolved organic matter (CDOM) fluorophores; this result is similar to those of other inland water bodies in China. The CDOM fluorophores showed similar seasonal and spatial variations with common water quality indices, with the exception of the seasonal responses of C2 in winter. Bivariance correlations between the organic and nutrient concentrations and the fluorescence intensities of the CDOM fluorophores imply possible common sources of the different contaminants. This paper exemplifies advanced statistical methods as a useful tool in understanding the behavior of contaminants in inland fresh water systems.

scholarly journals An assessment of the Effects of Housing Development on Water quality in Enugu Urban

2021 ◽  
pp. 33-37
Author(s):  
Eke B.L. ◽  
Essaghah A.E. ◽  
Okechukwu C.N.
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Surface Water ◽  
Water Sample ◽  
Environmental Quality ◽  
Surface Water Quality ◽  
Housing Development ◽  
Environmental Standards ◽  
Rivers And Streams ◽  
Enugu State

This study examined the effect of housing development on surface water quality in Enugu urban. The research design used for this study was experimental. A total of 11 samples of water were collected from the various selected site locations within the study area, in the three local government areas of Enugu urban. The water sample was collected with acid-washed and open dried polyethylene bottles, the samples were labeled according to their various rivers and streams, the polyethylene bottles were corked and were kept in ice-filled boxes, transported to PRODA for analysis. The major findings of the study showed that housing development in Enugu urban has a negative significant impact on water quality because Okwuosa river has an Organic matter level of 4.19 while WHO Limit is 2,9, therefore this aspect should be monitored for Okwuosa river in Enugu South. Other findings were Compared with the WHO standard and it showed that water quality deteriorates as housing development progresses. It is therefore the recommendation of the study that the housing authorities in Enugu state should institute measures to ensure that housing development does not compromise environmental quality and house owners and indeed all residents should be properly sensitized through environmental education on the dangers of abusing environmental standards.

scholarly journals Role of tributaries in Donbas in ensuring the quality of the Siverskyi Donets river surface water

2019 ◽  
pp. 64-71
Author(s):  
N. S. Loboda ◽  
O. V. Smalii
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Surface Water Quality ◽  
Ecological Condition ◽  
Donets Basin ◽  
Salt Composition ◽  
Ecological Index ◽  
Main River

The relevance of the work consists in the need to study the water quality of the Siverskyi Donets River and its tributaries at the beginning of the 21th century, since the river is a main source of water supply in the eastern part of Ukraine. The catchment area of the Siverskyi Donets River is located in the most industrialized region of Ukraine. It is a transboundary river and its catchment is located in the territory of both Ukraine and Russia. The volume of the river's water use, if compared to its runoff volume, is the largest in Ukraine. The condition of water quality is determined by high water consumption and large amount of polluted water being discharged into it. The largest impact is caused by discharges from the residential and commercial complex (big cities) and the enterprises of coal industry, ferrous metallurgy, chemical and petrochemical industry which are concentrated in the Donets Coal Basin. The purpose of this work is to assess the changes of surface water quality of the Siverskyi Donets Basin and to establish the role of the tributaries affected by considerable anthropogenic pressure in the formation of the ecological state of the main river. The research aims at analyzing the hydrochemical indices of the Siverskyi Donets River and its tributaries: the Udy River (9 km to the south from Kharkiv) located in the forest-steppe zone and affected by the wastewater of Kharkiv megalopolis; the Oskil River (Chervonooskilske Reservoir) located in the karst area, having a significant underground water supply and the runoff of which is regulated by the reservoir; the Luhan, Kryvyi Torets, Kazennyi Torets, Bakhmut rivers that are tributaries originating from the Donetsk Highlands and affected by the wastewater of Donbas industrial and municipal enterprises. The subject of the research is the ecological condition of water resources in the rivers of the Siverskyi Donets Basin estimated using the generalized ecological index. The water quality condition was analyzed based on the hydrochemical observations performed from 1990 to 2015 by Central Geophysical Observatory in Kyiv. The main method of research is the method of ecological assessment of surface water quality of land and estuaries in Ukraine using relevant categories. The assessment of the surface water quality using the generalized ecological index (with application of average indicators) showed that the water quality deteriorates along the main river with its worst condition at Lysychansk section. Analysis of the tributaries indicated the worst ecological condition of the Bakhmut River (Donbas). For most of the considered rivers the 3rd class of quality (“satisfactory”), the 4th category ("satisfactory condition and slightly contaminated”) were established. If we consider the index of ecological condition by maximum indicators, the results are almost the same for all the studied rivers: 5th class, 7th category ("very poor condition and very contaminated”). According to the block of salt composition components, the worst ecological condition is established for sections of the Siverskyi Donets River (city of Lysychansk) and the Bakhmut River. The analysis of the generalized ecological index  dynamics along the length of the main river indicated a general trend (except for the section in Lysychansk) to water quality improvement. This was achieved following the decrease of toxic effects due to reduction of petroleum products and phenol concentrations. No significant changes in the index were detected for the tributaries. Donbas rivers are also characterized by increase of the salt composition components index: their water is classified as "brackish" whereas the water of other tributaries is classified as “fresh water”. The pollution with nitrogen compounds still remains significant and keeps increasing. The heavy metals content decreases very slowly. The inflow of water of the Donbas rivers to the main river causes significant changes of the ecological condition at the Lysychansk section located downstream from the place of their confluence.

scholarly journals The Roles of Resuspension, Diffusion and Biogeochemical Processes on Oxygen Dynamics Offshore of the Rhone River, France: A Numerical Modeling Study

2016 ◽  
Author(s):  
Julia M. Moriarty ◽  
Courtney K. Harris ◽  
Christophe Rabouille ◽  
Katja Fennel ◽  
Marjorie A. M. Friedrichs ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Organic Matter ◽  
Oxygen Consumption ◽  
Water Column ◽  
Bottom Boundary Layer ◽  
Water Interface ◽  
Bottom Boundary ◽  
Rhône Delta ◽  
Oxygen Dynamics

Abstract. Observations indicate that seabed resuspension of organic material and the associated entrainment of porewater into the overlying water can alter biogeochemical fluxes in some environments, but measuring the role of sediment processes on oxygen and nutrient dynamics is challenging. A modeling approach offers a means of quantifying these fluxes for a range of conditions, but models have typically relied on simplifying assumptions regarding seabed-water column interactions. Thus, to evaluate the role of resuspension on biogeochemical dynamics, we developed a coupled hydrodynamic, sediment transport, and biogeochemical model (HydroBioSed) within the Regional Ocean Modeling System (ROMS). This coupled model accounts for processes including the storage of particulate organic matter (POM) and dissolved nutrients within the seabed; entrainment of this material into the water column via resuspension and diffusion at the sediment-water interface; and biogeochemical reactions within the seabed. A one-dimensional version of HydroBioSed was then implemented for the Rhone Delta, France. To isolate the role of resuspension on biogeochemical dynamics, this model implementation was run for a two-month period that included three resuspension events; also, the supply of organic matter, oxygen and nutrients to the water column was held constant in time. Consistent with time-series observations from the Rhone Delta, model results showed that resuspension increased the diffusive flux of oxygen into the seabed by increasing the vertical gradient of oxygen at the seabed-water interface. This enhanced supply of oxygen to the seabed allowed seabed oxygen consumption to increase, primarily through nitrification. Resuspension of POM into the water column, and the associated increase in remineralization, also increased oxygen consumption in the bottom boundary layer. During these resuspension events, modeled rates of oxygen consumption increased by up to factors of ~ 2 and ~ 8 in the seabed and bottom boundary layer, respectively. When averaged over two months, the intermittent cycles of erosion and deposition led to a 20 % increase of oxygen consumption in the seabed, as well as a larger increase of ~ 200 % in the bottom boundary layer. These results imply that observations collected during quiescent periods, and biogeochemical models that neglect resuspension or use typical parameterizations for resuspension, may underestimate net oxygen consumption at sites like the Rhone Subaqueous Delta. Local resuspension likely has the most pronounced effect on oxygen dynamics at study sites with a high oxygen concentration in the bottom boundary layer, only a thin seabed oxic layer, and abundant labile organic matter.

scholarly journals The roles of resuspension, diffusion and biogeochemical processes on oxygen dynamics offshore of the Rhône River, France: a numerical modeling study

2017 ◽  
Vol 14 (7) ◽  
pp. 1919-1946 ◽  
Author(s):  
Julia M. Moriarty ◽  
Courtney K. Harris ◽  
Katja Fennel ◽  
Marjorie A. M. Friedrichs ◽  
Kehui Xu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Water Column ◽  
Water Interface ◽  
Regional Ocean Modeling System ◽  
Biogeochemical Models ◽  
Rhône Delta ◽  
Rhone Delta ◽  
Oxygen Dynamics

Abstract. Observations indicate that resuspension and associated fluxes of organic material and porewater between the seabed and overlying water can alter biogeochemical dynamics in some environments, but measuring the role of sediment processes on oxygen and nutrient dynamics is challenging. A modeling approach offers a means of quantifying these fluxes for a range of conditions, but models have typically relied on simplifying assumptions regarding seabed–water-column interactions. Thus, to evaluate the role of resuspension on biogeochemical dynamics, we developed a coupled hydrodynamic, sediment transport, and biogeochemical model (HydroBioSed) within the Regional Ocean Modeling System (ROMS). This coupled model accounts for processes including the storage of particulate organic matter (POM) and dissolved nutrients within the seabed; fluxes of this material between the seabed and the water column via erosion, deposition, and diffusion at the sediment–water interface; and biogeochemical reactions within the seabed. A one-dimensional version of HydroBioSed was then implemented for the Rhône subaqueous delta in France. To isolate the role of resuspension on biogeochemical dynamics, this model implementation was run for a 2-month period that included three resuspension events; also, the supply of organic matter, oxygen, and nutrients to the model was held constant in time. Consistent with time series observations from the Rhône Delta, model results showed that erosion increased the diffusive flux of oxygen into the seabed by increasing the vertical gradient of oxygen at the seabed–water interface. This enhanced supply of oxygen to the seabed, as well as resuspension-induced increases in ammonium availability in surficial sediments, allowed seabed oxygen consumption to increase via nitrification. This increase in nitrification compensated for the decrease in seabed oxygen consumption due to aerobic remineralization that occurred as organic matter was entrained into the water column. Additionally, entrainment of POM into the water column during resuspension events, and the associated increase in remineralization there, also increased oxygen consumption in the region of the water column below the pycnocline. During these resuspension events, modeled rates of oxygen consumption increased by factors of up to  ∼  2 and  ∼  8 in the seabed and below the pycnocline, respectively. When averaged over 2 months, the intermittent cycles of erosion and deposition led to a  ∼  16 % increase of oxygen consumption in the seabed, as well as a larger increase of  ∼  140 % below the pycnocline. These results imply that observations collected during quiescent periods, and biogeochemical models that neglect resuspension or use typical parameterizations for resuspension, may underestimate net oxygen consumption at sites like the Rhône Delta. Local resuspension likely has the most pronounced effect on oxygen dynamics at study sites with a high oxygen concentration in bottom waters, only a thin seabed oxic layer, and abundant labile organic matter.

AN EVALUATION OF SUB-SURFACE WATER QUALITY AROUND BHARUCH-SURAT INDUSTRIAL REGION, GUJARAT, INDIA

2019 ◽  
Vol 38 (2) ◽  
pp. 200-220
Author(s):  
SOMNATH SAHA ◽  
◽  
SUKANTA KUMAR SAHA ◽  
TATHAGATA GHOSH ◽  
ROLEE KANCHAN ◽  
...  
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Surface Water Quality ◽  
Industrial Region
Sign in / Sign up

Export Citation Format

Share Document