scholarly journals Wind Exposure Regulates Water Oxygenation in Densely Vegetated Shallow Lakes

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1269
Author(s):  
Cristina Ribaudo ◽  
Juliette Tison-Rosebery ◽  
Mélissa Eon ◽  
Gwilherm Jan ◽  
Vincent Bertrin
Keyword(s):  
Shallow Lakes ◽  
Shallow Lake ◽  
Inorganic Compounds ◽  
Oxygen Demand ◽  
Strong Wind ◽  
Critical Periods ◽  
Labile Organic Matter ◽  
Water Mixing ◽  
Hypoxic Conditions ◽  
Wind Exposure

The presence of dense macrophyte canopies in shallow lakes locally generates thermal stratification and the buildup of labile organic matter, which in turn stimulate the biological oxygen demand. The occurrence of hypoxic conditions may, however, be buffered by strong wind episodes, which favor water mixing and reoxygenation. The present study aims at explicitly linking the wind action and water oxygenation within dense hydrophytes stands in shallow lakes. For this purpose, seasonal 24 h-cycle campaigns were carried out for dissolved gases and inorganic compounds measurements in vegetated stands of an oligo-mesotrophic shallow lake. Further, seasonal campaigns were carried out in a eutrophic shallow lake, at wind-sheltered and -exposed sites. Overall results showed that dissolved oxygen (DO) daily and seasonal patterns were greatly affected by the degree of wind exposure. The occurrence of frequent wind episodes favored the near-bottom water mixing, and likely facilitated mechanical oxygen supply from the atmosphere or from the pelagic zone, even during the maximum standing crop of plants (i.e., summer and autumn). A simple model linking wind exposure (Keddy Index) and water oxygenation allowed us to produce an output management map, which geographically identified wind-sheltered sites as the most subjected to critical periods of hypoxia.

scholarly journals Sediment Phosphate Release Flux Under Hydraulic Disturbances in the Shallow Lake of Chaohu, China

2021 ◽  
Author(s):  
Wenguang LUO ◽  
Yao Yue ◽  
Jing Lu ◽  
Lina Pang ◽  
Senlin Zhu
Keyword(s):  
Shallow Lakes ◽  
Release Rate ◽  
Surface Sediment ◽  
Shallow Lake ◽  
Chaohu Lake ◽  
Small Motion ◽  
Phosphate Release ◽  
Wide Range ◽  
Sediment Phosphate ◽  
Motion Mode

Abstract Quantifying the effect of hydraulic disturbances on sediment phosphate release is a key issue in the water quality assessment of lakes, especially for the shallow lakes which are susceptible to winds and waves. Here, we sampled the original sediment columns from 12 positions in the eastern, central, and western areas of the Chaohu Lake, a representative shallow lake in China, and observed phosphate release under three levels of hydraulic disturbances in the laboratory. When the disturbance was weak and the surface sediment of bottom mud moved individually (the Individual Motion Mode), sediment phosphate release rate was insignificant (0.24 mg/m2/d). When the disturbance was medium and only a small percentage (<16%) of surface sediment started to move (the Small Motion Mode), phosphate release rate sharply increased to 4.81 mg/m2/d. When the disturbance was further strengthened and most (≥16%) of the surface sediment moved (the General Motion Mode), phosphate release rate was more than doubled (10.23 mg/m2/d). With the increase of hydraulic disturbance intensity, the variation range of phosphate release also became wider. Spatial distribution showed that the release rate varies the most in the western area, followed by the eastern and the central areas. By extrapolating the experimental results to the real scale, we found the phosphate release fluxes would probably fall within a wide range between 203.43 kg/d to 7311.01kg/d under different levels of hydrodynamic disturbances with considerably affects phosphate release from shallow lakes. This study also has implications for the pollutant management in other shallow lakes.

scholarly journals First record of the endemic phytophilous cladoceran Celsinotum candango Sinev & Elmoor-Loureiro, 2010, in Minas Gerais state, in a threatened shallow lake at Serra do Gandarela

2015 ◽  
Vol 15 (4) ◽  
Author(s):  
Francisco Wagner Moreira ◽  
Emerson Silva Dias ◽  
Eneida Maria Eskinazi Sant'Anna
Keyword(s):  
Shallow Lakes ◽  
Shallow Lake ◽  
Aquatic Ecosystems ◽  
National Park ◽  
Federal District ◽  
First Record ◽  
Minas Gerais ◽  
Mountain Ridge ◽  
Aquatic Biodiversity ◽  
Minas Gerais State

This study describes the occurrence of the phytophilous cladoceran Celsinotum candango, which has been considered, up to now, an endemic species of the Brazilian Cerrado, with only two previous records in the wetlands of Brasilia, Federal District. The cladoceran has now been registered at Coutos Lake (“Lagoa dos Coutos”), an altitudinal, temporary shallow lake, located in ironstone outcrops at Serra do Gandarela, Minas Gerais state. This mountain ridge was recently turned into an integral protection conservation unit, the Gandarela National Park. However, many shallow lakes, including this one, were excluded from the delimited area of the park, and are now at risk of disappearing due to expansion of mining activities. The information provided here reveals the importance of these shallow lakes to aquatic biodiversity, and reinforces the need for the inclusion of these rare aquatic ecosystems into the recently created Gandarela National Park.

scholarly journals Effects of Human Activities on the Diversity of Waterbirds Wintering in a Shallow Lake of the Middle and Lower Yangtze River Floodplain, China

Diversity ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 302
Author(s):  
Xinjian Wang ◽  
Jinyun Chen ◽  
Lizhi Zhou
Keyword(s):  
Species Composition ◽  
Human Activity ◽  
Shallow Lakes ◽  
Shallow Lake ◽  
Yangtze River ◽  
Paddy Fields ◽  
Aquaculture Ponds ◽  
Lower Yangtze ◽  
Lake Wetlands ◽  
Wetland Habitats

Human activity is the major factor driving the wetland degradation in shallow lakes. Human exploitation of lake wetlands alters the habitats of wintering waterbirds, and, in turn, waterbird diversity in the shallow lakes. In the present study, we surveyed species composition, abundance, and habitat characteristics of waterbirds in three types of wetland habitats (natural lakeside wetlands, paddy fields, and aquaculture ponds) at Caizi Lake, a shallow lake in the middle and lower Yangtze River during the wintering period, and investigated the effects of habitat change driven by human activity on the diversity of wintering waterbirds. There were significant differences in species composition and abundance among the three wetland habitats (natural lakeside wetlands, aquaculture ponds, and artificial paddy fields); however, there were no significant differences among the habitats with respect to the number of waterbirds. The numbers of overwintering waterbird species and waterbird individuals in aquaculture ponds and lakeside wetlands were significantly higher than the numbers in the paddy fields, indicating that wintering waterbirds prefer natural lake wetlands and aquaculture ponds. Principal component analysis of the three wetland habitat types revealed that factors influencing waterbird diversity include wetland area, vegetation cover, water level, and degree of human interference. Therefore, minimizing human interference and ensuring suitable habitats at specific periods could facilitate the maintenance of waterbird diversity.

Comparison of Photo-Fenton Treatment and Coupled Photo-Fenton and Biological Treatment for Detoxification of Pharmaceutical Industry Contaminants

2008 ◽  
Vol 11 (2) ◽  
Author(s):  
Ana Zapata ◽  
Isabel Oller ◽  
Raphael Gallay ◽  
César Pulgarín ◽  
Manuel Ignacio Maldonado ◽  
...  
Keyword(s):  
Pharmaceutical Industry ◽  
Acute Toxicity ◽  
Biological Treatment ◽  
Vibrio Fischeri ◽  
Inorganic Compounds ◽  
Oxygen Demand ◽  
Significant Degree ◽  
Synthetic Wastewater ◽  
Toxicity Tests ◽  
Oxidative Treatment

AbstractThis paper compares the feasibility of two different treatment approaches, chemical oxidative treatment by the solar photo-Fenton method and a combined approach applying the solar photo-Fenton method as a pre-treatment for aerobic biological wastewater treatment. The targets are two biorecalcitrant substances used as synthesis intermediates in the pharmaceutical industry, 2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-ylmethanol (CAS 84682-23-5) (DIDM) and 2-(2,4-dichlorophenyl)-2-(1H-1,2,4-triazol-1-ylmethyl)- 1,3-dioxolan-4-ylmethanol (CAS 67914-85-6) (DTDM). Solar photo-Fenton treatment was performed in Compound Parabolic Collector pilot-plants, and biological treatment in an immobilized biomass reactor pilot-plant. Analytical determinations included the measurement of dissolved organic carbon, chemical oxygen demand, inorganic compounds (chloride, ammonium, nitrate), formed during degradation, acute toxicity tests applying Vibrio Fischeri luminescence bacteria and the Zahn-Wellens biodegradability test. The synthetic wastewater contained 200 mg/L of each compound, an initial DOC of 200 mg/l and an initial COD of 700 mg/L. The target compounds proved to be susceptible to complete degradation and partial mineralization (95%) by photo-Fenton. Total elimination of both substances occurred after 74 minutes of illumination and required the consumption of 27.5 mM of hydrogen peroxide. Nevertheless, acute toxicity persisted practically to the end of the treatment, and biodegradability could only be slightly enhanced, never rendering the wastewater completely biodegradable at any stage of the chemical oxidative treatment. By Zahn-Wellens test DIDM and DTDM proved to be non-biodegradable and only samples pre-treated by photo-Fenton until achieving a DOC below 98 mg/L showed a significant degree of biodegradability (60% after 11 days of biotreatment). This particular behaviour contrasts with other substances that have been tested before and may be related to the refractory nature of the imidazole and triazole moieties in the molecular structure of DIDM and DTDM.

scholarly journals Anammox, denitrification and fixed-nitrogen removal in sediments from the Lower St. Lawrence Estuary

2012 ◽  
Vol 9 (11) ◽  
pp. 4309-4321 ◽  
Author(s):  
S. A. Crowe ◽  
D. E. Canfield ◽  
A. Mucci ◽  
B. Sundby ◽  
R. Maranger
Keyword(s):  
Nitrate Reduction ◽  
Sediment Cores ◽  
Oxygen Demand ◽  
N Cycling ◽  
Fixed Nitrogen ◽  
Lawrence Estuary ◽  
Hypoxic Conditions ◽  
Nitrate And Nitrite ◽  
St Lawrence Estuary

Abstract. Incubations of intact sediment cores and sediment slurries reveal that anammox is an important sink for fixed nitrogen in sediments from the Lower St. Lawrence Estuary (LSLE), where it occurs at a rate of 5.5 ± 1.7 µmol N m−2 h−1. Canonical denitrification occurs at a rate of 11.3 ± 1.1 µmol N m−2 h−1, and anammox is thus responsible for up to 33% of the total N2 production. Both anammox and denitrification are mostly (> 95%) fueled by nitrate and nitrite produced in situ through benthic nitrification. Nitrification accounts for > 15% of the benthic oxygen demand and may, therefore, contribute significantly to the development and maintenance of hypoxic conditions in the LSLE. The rate of dissimilatory nitrate reduction to ammonium is three orders of magnitude lower than denitrification and anammox, and it is insignificant to N-cycling. NH4+ oxidation by sedimentary Fe(III) and Mn(III/IV) in slurry incubations with N isotope labels did not occur at measurable rates; moreover, we found no evidence for NH4+ oxidation by added Mn(III)-pyrophosphate.

Peculiarities of macrozoobenthos in the offshore zone of a small artificial post-gravel pit reservoir

2010 ◽  
Vol 39 (1) ◽  
Author(s):  
Janusz Żbikowski ◽  
Jarosław Kobak
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Environmental Parameters ◽  
Matter Content ◽  
Artificial Reservoir ◽  
Hypoxic Conditions ◽  
Gravel Pit ◽  
Wind Exposure ◽  
Sand And Gravel ◽  
High Fish

Peculiarities of macrozoobenthos in the offshore zone of a small artificial post-gravel pit reservoirThe offshore macrozoobenthos and selected environmental parameters were studied in a small artificial reservoir, created through sand and gravel extraction. The results are rather surprising. Despite the shallow depth and good wind exposure of the reservoir, a thermal and oxygen stratification developed in the summer, causing hypoxic conditions near the bottom, even though the organic matter content in the sediments was <5%. Furthermore, despite the high fish abundance, chaoborids prevailed in zoobenthos, while

scholarly journals Reconsideration of winds, wind waves, and turbulence in simulating wind-driven currents of shallow lakes in the Wave-current Coupled Model (WCCM) version 1.0

2021 ◽  
Author(s):  
Tingfeng Wu ◽  
Boqiang Qin ◽  
Anning Huang ◽  
Yongwei Sheng ◽  
Shunxin Feng ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Shallow Lakes ◽  
Shallow Lake ◽  
Lake Taihu ◽  
Wind Waves ◽  
Coupled Model ◽  
Field Observations ◽  
Radiation Stress ◽  
Wind Driven Currents ◽  
Wave Induced

Abstract. Winds, wind waves, and turbulence are essential variables and playing critical role in regulating a series of physical and biogeochemical processes in large shallow lakes. However, parameterizing winds, waves, currents and turbulence and simulating the interaction between them in large shallow lakes haven’t been evaluated strictly because of a lack of field observations of lake hydrodynamics process. To address this problem, two process-based field observations were conducted to record the development of summer and winter wind-driven currents in Lake Taihu, a large shallow lake in China. Based on these observations and numerical experiments, a wave-current coupled model (WCCM) is developed by rebuilding expression of wind drag coefficient, introducing wave-induced radiation stress, and adopting a simple turbulence scheme, and then used to simulate wind-driven currents in Lake Taihu. The results show that, the WCCM can accurately simulate the upwelling process resulting from the wind-driven currents during the field observations. Comparing with other model, there is a 42.9 % increase of WCCM-simulated current speed which is mainly attributed to the new expression of wind drag coefficient. Meanwhile WCCM-simulated current direction and field are also improved due to the introduction of wave-induced radiation stress. Furthermore, the use of the simple turbulent scheme in the WCCM makes the simulation of the upwelling processes more efficient. The WCCM provides a sound basis for simulating shallow lake ecosystems.

scholarly journals Dynamics and Economics of Shallow Lakes: A Survey

2021 ◽  
Vol 13 (24) ◽  
pp. 13763
Author(s):  
Dmitry Gromov ◽  
Thorsten Upmann
Keyword(s):  
Linear Model ◽  
Shallow Lakes ◽  
Shallow Lake ◽  
Regime Shift ◽  
Multiple Steady States ◽  
Typical Representative ◽  
Lake Model ◽  
Ecological Problems ◽  
Multiple Domains ◽  
Substantial Interest

We provide an overview of the results devoted to the analysis of the dynamics and economics of shallow lakes, spanning the period from 1999 until now. A shallow lake serves as a typical representative of an ecological system subject to (possibly irreversible) regime shifts. The dynamics of a shallow lake are described by a non-linear model with multiple steady states and multiple domains of attraction and is thus suitable to model the evolution of an ecosystem featuring both resilience within a domain of stability and an abrupt regime shift outside of it. Beyond this, the shallow lake model can also be viewed as a metaphor for many other ecological problems. Due to the broad applicability of this model, there is substantial interest in the management of shallow lakes and both their optimal regulation and competitive usage.

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