scholarly journals Trajectories of Sediment-Water Interactions in Reservoirs as a Result of Temperature and Oxygen Conditions

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1065
Author(s):  
Tallent Dadi ◽  
Karsten Rinke ◽  
Kurt Friese
Keyword(s):  
High Temperature ◽  
Seasonal Changes ◽  
Algal Blooms ◽  
Sediment Cores ◽  
Nutrient Release ◽  
Reservoir Temperature ◽  
Overlying Water ◽  
Eutrophic Reservoir ◽  
Reducing Conditions ◽  
Oxygen Conditions

Temperate lakes/reservoirs are warming; this can influence the benthic release of nutrients. They undergo seasonal changes resulting in an array of temperature and oxygen conditions; oxic-low, oxic-high, anoxic-low, and anoxic-high temperature. We sought to understand the interaction of temperature and oxygen conditions on benthic solutes exchange through a two-factorial sediment core incubation experiment by varying either temperature or oxygen conditions of sediment cores from an oligotrophic and eutrophic reservoir. Temperature and oxygen conditions are both important for nutrient release; however, they influence solutes differently; differences in the fluxes of the treatments were explained more by temperature for P, DOC and N, while for Fe, Mn and SO42−, differences were explained more by oxygen conditions. The combination of strongly reducing conditions (due to anoxia) and high temperature (20 °C) led to a significant increase in nutrients concentrations in the overlying water. Under these conditions, SRP flux was 0.04 and 0.5 mmol m−2 d−1; ammonium was 0.9 and 5.6 mmol m−2 d−1 for the oligotrophic and eutrophic reservoir, respectively. We observed a synergistic interaction between temperature and oxygen conditions which resulted in release of solutes from sediments. An increase in nutrients release under increasing temperatures is more likely and so are algal blooms.

scholarly journals Behaviour of Metal(loid)s at the Sediment-Water Interface in an Aquaculture Lagoon Environment (Grado Lagoon, Northern Adriatic Sea, Italy)

2021 ◽  
Vol 11 (5) ◽  
pp. 2350
Author(s):  
Elisa Petranich ◽  
Matteo Crosera ◽  
Elena Pavoni ◽  
Jadran Faganeli ◽  
Stefano Covelli
Keyword(s):  
Sediment Cores ◽  
Fish Farm ◽  
Trophic Chain ◽  
Water Interface ◽  
Northern Adriatic Sea ◽  
Overlying Water ◽  
Northern Adriatic ◽  
In Situ Experiments ◽  
Diffusive Fluxes ◽  
Lagoon Environment

The cycling of metal(loid)s at the sediment–water interface (SWI) was evaluated at two selected sites (VN1 and VN3) in an active fish farm in the Grado Lagoon (Northern Adriatic, Italy). In situ experiments using a transparent benthic chamber and the collection of short sediment cores were performed, to investigate the behavior of metal(loid)s in the solid (sediments) and dissolved (porewaters) phases. Total and labile concentration of metal(loid)s were also determined in sediments, to quantify their potential mobility. Comparable total concentrations were found at both sites, excluding As, Mn, Pb and V, which were higher at VN3. Metal(loid) porewater profiles showed a diagenetic sequence and a close dependence with redox (suboxic/anoxic) conditions in the surface sediments. Positive diffusive fluxes along with benthic fluxes, particularly at the more oxic site, VN1, were found for almost all metal(loid)s, indicating their tendency to migrate towards the overlying water column. Despite sediments at two sites exhibiting high total metal(loid) concentrations and moderate effluxes at the SWI, the results suggest that they are hardly remobilized from the sediments. Recycling of metal(loid)s from the SWI would not constitute a threat for the aquatic trophic chain in the fish farm.

scholarly journals Quantitative and qualitative constraints on hind-casting the formation of multiyear lake-ice covers at Lake El'gygytgyn

2013 ◽  
Vol 9 (3) ◽  
pp. 1253-1269 ◽  
Author(s):  
M. Nolan
Keyword(s):  
Water Exchange ◽  
Sediment Cores ◽  
Ice Cover ◽  
Lake Ice ◽  
Ice Growth ◽  
Temperature Reduction ◽  
Air Temperatures ◽  
Lake El’Gygytgyn ◽  
Oxygen Conditions ◽  
Multiyear Ice

Abstract. Analysis of the 3.6 Ma, 318 m long sediment core from Lake El'gygytgyn suggests that the lake was covered by ice for millennia at a time for much of its history and therefore this paper uses a suite of existing, simple, empirical degree-day models of lake-ice growth and decay to place quantitative constraints on air temperatures needed to maintain a permanent ice cover on the lake. We also provide an overview of the modern climatological and physical processes that relate to lake-ice growth and decay as a basis for evaluating past climate and environmental conditions. Our modeling results indicate that modern annual mean air temperature would only have to be reduced by 3.3 °C ± 0.9 °C to initiate a multiyear ice cover and a temperature reduction of at least 5.5 °C ± 1.0 °C is likely needed to completely eliminate direct air–water exchange of oxygen, conditions that have been inferred at Lake El'gygytgyn from the analysis of sediment cores. Once formed, a temperature reduction of only 1–3 °C relative to modern may be all that is required to maintain multiyear ice. We also found that formation of multiyear ice covers requires that positive degree days are reduced by about half the modern mean, from about +608 to +322. A multiyear ice cover can persist even with summer temperatures sufficient for a two-month long thawing period, including a month above +4 °C. Thus, it is likely that many summer biological processes and some lake-water warming and mixing may still occur beneath multiyear ice-covers even if air–water exchange of oxygen is severely restricted.

scholarly journals Responses of food web to hypolimnetic aeration in Lake Vesijärvi

Hydrobiologia ◽  
2020 ◽  
Vol 847 (21) ◽  
pp. 4503-4523 ◽  
Author(s):  
Jukka Ruuhijärvi ◽  
Tommi Malinen ◽  
Kirsi Kuoppamäki ◽  
Pasi Ala-Opas ◽  
Mika Vinni
Keyword(s):  
Body Size ◽  
Food Web ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Perca Fluviatilis ◽  
Fish Predation ◽  
Filamentous Cyanobacteria ◽  
Low Oxygen ◽  
High Quality ◽  
Oxygen Conditions

AbstractWe studied the responses of a food web, especially fish and zooplankton, to summertime aeration, pumping of oxygen-rich epilimnetic water to the hypolimnion in Lake Vesijärvi, southern Finland. The aim of hypolimnetic aeration was to reduce internal loading of phosphorus from sediment. The population of smelt (Osmerus eperlanus L.), the main planktivore of the pelagial area, collapsed during the two 1st years of aeration due to increased temperature and low oxygen concentrations in the hypolimnion. The population recovered after the 4th year of hypolimnetic aeration, when oxygen conditions were improved. Despite elevated hypolimnetic temperature, smelt reached exceptionally high abundance, which led to a significant reduction in cladoceran body size. The density of perch (Perca fluviatilis L.) increased at first, but then decreased when the proportion of smelt and cyprinids increased. Biomasses of Daphnia decreased probably as a result of the disappearance of dark, low-oxygen deep-water refuge against fish predation and low availability of nutritionally high-quality algae. Occasionally filamentous cyanobacteria, such as turbulence tolerant Planktothrix agardhii (Gomont), were abundant, suggesting deteriorated food resources for zooplankton. The responses of food web were controversial with respect to the aim of the management, which was to prevent the occurrence of harmful algal blooms.

Benthic exchange of sedimentary metals (Cd, Cu, Fe, Mn, Ni and Zn) in the Deûle River (Northern France)

2012 ◽  
Vol 9 (5) ◽  
pp. 485 ◽  
Author(s):  
Beatriz Lourino-Cabana ◽  
Ludovic Lesven ◽  
Gabriel Billon ◽  
Lionel Denis ◽  
Baghdad Ouddane ◽  
...  
Keyword(s):  
Trace Metal ◽  
Sediment Cores ◽  
Metal Exchange ◽  
Negative Effects ◽  
Overlying Water ◽  
Colloidal Iron ◽  
Northern France ◽  
Anoxic Events ◽  
Co Precipitation ◽  
Sediment Interface

Environmental context Exchange processes at the water–sediment interface can release metals to riverine waters, having negative effects on organisms in the water column. We investigate the geochemical processes and metal exchange between the surface sediment and the overlying water under metal contamination conditions. Results suggest that the sediment can be a significant source of metal pollution in aquatic systems, particularly during anoxic events. Abstract Experiments were performed on the Deûle River (Northern France), which is strongly polluted by smelting plants, in the aim to investigate the influence of diagenetic processes and benthic macro-faunal activity on trace metal (Cd, Cu, Ni and Zn) and major metal (Fe, Mn) exchanges occurring at the water–sediment interface. Diffusive metal fluxes were determined from pore water metal concentration gradients measured in sediment cores. Benthic metal fluxes were evaluated using incubation chambers under dark conditions, and by further examining key variables (O2, CO2, redox potential and pH) affecting metal release and sequestration processes. As a whole, it was demonstrated that benthic fluxes were strongly dependent upon medium oxygenation and generation of colloidal iron oxides and hydroxides at the overlying water–sediment interface, raising the possibility of trace-metal adsorption and (co)precipitation.

scholarly journals A Sediment Diagenesis Model of Seasonal Nitrate and Ammonium Flux Spatial Variation Contributing to Eutrophication at Taihu, China

2020 ◽  
Vol 17 (11) ◽  
pp. 4158 ◽  
Author(s):  
Linda Sarpong ◽  
Yiping Li ◽  
Eyram Norgbey ◽  
Amechi S. Nwankwegu ◽  
Yue Cheng ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Column ◽  
Algal Blooms ◽  
Latin Hypercube Sampling ◽  
Sediment Flux ◽  
Low Oxygen ◽  
Four Seasons ◽  
Sediment Diagenesis ◽  
Oxygen Conditions ◽  
Autumn And Winter

Algal blooms have thrived on the third-largest shallow lake in China, Taihu over the past decade. Due to the recycling of nutrients such as nitrate and ammonium, this problem has been difficult to eradicate. Sediment flux, a product of diagenesis, explains the recycling of nutrients. The objective was to simulate the seasonal spatial variations of nitrate and ammonium flux. In this paper, sediment diagenesis modeling was applied to Taihu with Environmental Fluid Dynamics Code (EFDC). Latin hypercube sampling was used to create an input file from twelve (12) nitrogen related parameters of sediment diagenesis and incorporated into the EFDC. The results were analyzed under four seasons: summer, autumn, winter, and spring. The concentration of NH4–N in the sediment–water column increased from 2.744903 to 22.38613 (g/m3). In summer, there was an accumulation of ammonium in the water column. In autumn and winter, the sediment was progressively oxidized. In spring, low-oxygen conditions intensify denitrification. This allows algal blooms to continue to thrive, creating a threat to water quality sustainability. The sediment diagenesis model, coupled with water quality measured data, showed an average relative error for Total Nitrogen (TN) of 38.137%, making the model suitable. Future studies should simulate phosphate flux and measure sediment fluxes on the lake.

Shallow sediment temperature perturbations and sediment thermal conductivities, Canadian Beaufort Shelf

1987 ◽  
Vol 24 (11) ◽  
pp. 2223-2234 ◽  
Author(s):  
Alan E. Taylor ◽  
Vic Allen
Keyword(s):  
Thermal Effects ◽  
Seasonal Changes ◽  
Sediment Cores ◽  
Deep Ocean ◽  
Regional Survey ◽  
Bottom Water Temperature ◽  
Depth Profiles ◽  
Wide Range ◽  
Temperature Depth ◽  
Thermal Conductivities

A regional survey of sediment temperatures and thermal conductivities was conducted at 33 stations across the outer shelf of the Canadian Beaufort Sea. Techniques developed for deep-ocean heat-flow investigations were used to study the upper 3 m of sediments. Temperature–depth profiles exhibit curvatures that may be explained by seasonal changes in bottom-water temperature; some curvatures may arise from other causes. It is unlikely that thermal effects of the underlying, degradational permafrost can be detected from such shallow temperatures because of the magnitude of, and lack of independent knowledge of, these transient and local influences. Thermal conductivities measured on sediment cores and corrected to −1 °C range from 0.9 to 2.4 W m−1 K−1 (average 1.26 ± 0.2 W m−1 K−1). These values are higher than typical conductivities of deep-ocean sediments. The wide range of thermal conductivities observed across the outer Beaufort Shelf may be explained by the presence of a varying fraction of quartz sand that represents a component of high conductivity.

Survival of Hypoxic Conditions by the Polychaete Cirriformia Tentaculata

1980 ◽  
Vol 60 (2) ◽  
pp. 509-516 ◽  
Author(s):  
R. P. Dales ◽  
Lynda M. Warren
Keyword(s):  
Oxygen Uptake ◽  
Vascular System ◽  
Main Body ◽  
Stagnant Water ◽  
Overlying Water ◽  
Respiratory Problems ◽  
Hypoxic Conditions ◽  
Oxygen Capacity ◽  
Reducing Conditions ◽  
Potential Oxygen

The cirratulid polychaete Cirriformia tentaculata (Montagu) may be found in gravelly mud or sand often beneath large stones in pools between tide marks. It is usually associated with reducing conditions indicated by blackened mud or sand and the distinctive odour of hydrogen sulphide. It occurs also in crevices that retain stagnant water at low tide. The worm does not make a permanent burrow but lies in different postures to enable the branchiae and feeding tentacles to be extended on to the surface, where they are bathed by the overlying water. The mucus-lined burrow is not irrigated.Cirriformia tentaculata encounters two respiratory problems. When covered by water the branchial filaments can take up oxygen which is then circulated by means of the well-developed vascular system with blood containing haemoglobin in solution. While the branchiae may lie in a well-oxygenated medium the main body of the worm lies in a highly reducing substrate. The sediment immediately surrounding the worm is commonly black and there is no oxygenated layer as occurs in burrows which are irrigated and provide an envelope separating the animal from a potential oxygen-sink. If exposed by the tide the branchiae are withdrawn or clump together and cannot function effectively. Even when covered by the tide the branchiae can be rapidly with-drawn, presumably to avoid loss by predation, and under all these conditions the animal must experience hypoxic or anoxic conditions of varying duration of up to several hours.We have examined the ability of Cirriformia tentaculata to maintain oxygen uptake under decreasing oxygen tension, the oxygenational properties of the haemoglobin, the oxygen capacity and blood volume.

Seasonal and thermal effects on the emetic responses of ranid frogs

1996 ◽  
Vol 74 (11) ◽  
pp. 2009-2015 ◽  
Author(s):  
Chiharu Suzuki ◽  
Satoshi Miyoshi ◽  
Tomio Naitoh ◽  
Richard J. Wassersug
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Copper Sulfate ◽  
Temperature Sensitivity ◽  
Thermal Effects ◽  
Seasonal Changes ◽  
Seasonal Fluctuation ◽  
Rana Nigromaculata ◽  
Time Of Year ◽  
The Relationship

We examined the relationship between time of the year and sensitivity to emetics in the frogs Rana rugosa and Rana nigromaculata. In response to apomorphine hydrochloride at a dosage of 50 μg/g body mass (wet mass), both species vomited from the late autumn through the winter, when they naturally hibernate, but not during the spring or summer months, when they are normally active. Exposure to low temperature (7 °C) for 29 days made R. rugosa sensitive to apomorphine even in the summer. Exposure to high temperature (20.0–23.0 °C) for 7–10 days in the winter resulted in loss of the frogs' sensitivity to apomorphine. Based on these results, we conclude that seasonal fluctuation in sensitivity to apomorphine is caused by changes in temperature. Sensitivity to copper sulfate, administered orally at a dosage of 0.4 mg/g, also changed with the time of year. However, in contrast to emesis induced with apomorphine, there was an increase in the latency to emesis induced with copper sulfate in the winter compared with the summer for both species. Thus, the emetic responsiveness of ranid frogs depends on both seasonal changes in temperature and on the agent used to provoke emesis.

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