Future projections of temperature and mixing regime of European temperate lakes

Hydrology and earth system sciences, Год журнала: 2019, Номер 23(3), С. 1533 - 1551

Опубликована: Март 18, 2019

Abstract. The physical response of lakes to climate warming is regionally variable and highly dependent on individual lake characteristics, making generalizations about their development difficult. To qualify the role characteristics in homogeneous warming, we simulated temperature, ice cover, mixing four intensively studied German varying morphology regime with a one-dimensional model. We forced model an ensemble 12 projections (RCP4.5) up 2100. were projected warm at 0.10–0.11 ∘C decade−1, which 75 %–90 % air temperature trend. In simulations, surface temperatures increased strongly winter spring, but little or not all summer autumn. Mean bottom increase lakes, steeper trends shallower lakes. Modelled thaw stratification advanced by 1.5–2.2 1.4–1.8 days decade−1 respectively, whereas autumn turnover freeze timing was less sensitive. mixed-layer depth unaffected sensitive changes water transparency. By mid-century, frequency stratification-free winters 20 %, cover rare shifting two deeper dimictic predominantly monomictic regime. polymictic unlikely become end century. A sensitivity analysis predicted that decreasing transparency would dampen effect mean amplify its stratification. However, this interaction only occur clear study historical Not morphology, also determines how heat stored ultimately respond warming. Seasonal differences rates are thus important require more attention.

Язык: Английский

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Potential role of submerged macrophytes for oxic methane production in aquatic ecosystems

Limnology and Oceanography, Год журнала: 2022, Номер 67(S2)

Опубликована: Май 10, 2022

Abstract Methane (CH 4 ) from aquatic ecosystems contributes to about half of total global CH emissions the atmosphere. Until recently, biogenic production was exclusively attributed methanogenic archaea living under anoxic or suboxic conditions in sediments, bottom waters, and wetlands. However, evidence for oxic (OMP) freshwater, brackish, marine habitats is increasing. Possible sources were found be driven by various planktonic organisms supporting different OMP mechanisms. Surprisingly, submerged macrophytes have been fully ignored studies on OMP, yet they are key components littoral zones ponds, lakes, coastal systems. High concentrations these organic substrate promoting classic methanogenesis absence oxygen. Here, we review existing argue that, similar terrestrial plants phytoplankton, macroalgae may directly indirectly contribute formation waters. We propose several potential direct indirect mechanisms: (1) ; (2) precursors facilitation their bacterial breakdown chemical conversion; (3) methanogenesis; (4) ebullition. As occur many freshwater habitats, important carbon budgets can strongly vary abundance due seasonal boom‐bust dynamics. Knowledge contribution therefore essential gain a better understanding spatial temporal dynamics thus substantially reduce current uncertainties when estimating ecosystems.

Язык: Английский

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Applying Multi-Layer Artificial Neural Network and Mutual Information to the Prediction of Trends in Dissolved Oxygen

Frontiers in Environmental Science, Год журнала: 2019, Номер 7

Опубликована: Апрель 16, 2019

Predicting {\color{red}{trends in water quality}} plays an essential role the field of environmental modelling. Though artificial neural networks (ANN) have been involved predicting quality many studies, prediction performance is highly affected by model's inputs and network structure. Many researchers selected variables based on Pearson correlation. However, this kind method can only capture linear dependencies. Moreover, when dealing with multivariate data, ANN single layer few numbers units show difficulties representing complex inner relationships between multiple variables. Hence, paper we propose a novel {\color{red}{model}} multi-layer (MANN) mutual information (MI) for trend dissolved oxygen. MI used to evaluate choose taking into account {\color{red}{the non-linear variables}}. A MANN model built learn levels representations approximate regression functions. Water data collected from Baffle Creek, Australia was experiment. Our had around 0.95 0.94 $R^2$ scores 90 mins or 120 ahead last observed wet season, which are much higher than typical model, support vector regressor (SVR) (LRM). The results indicate that our provide accurate predictions DO upcoming hours useful supportive tool management aquatic ecosystems.

Язык: Английский

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A Spatially Integrated Dissolved Inorganic Carbon (SiDIC) Model for Aquatic Ecosystems Considering Submerged Vegetation

Journal of Geophysical Research Biogeosciences, Год журнала: 2023, Номер 128(2)

Опубликована: Фев. 1, 2023

Abstract Net ecosystem production (NEP) by submerged aquatic vegetation plays a substantial role in capturing atmospheric carbon dioxide into ecosystems. In lakes and estuaries, the net uptake of is mediated stratification water column which suppresses vertical flux between upper lower layers. The presence can also affect strength such that interactions vegetation, stratification, NEP moderate emissions. Since occur there need for new numerical approach able to consider effect on NEP, dioxide. This study aims develop model investigate how density flexibility, affects partial pressure ( p CO 2 ) dissolved inorganic (DIC). After initial parameterization coefficients based experimental work, horizontal variations DIC were successfully modeled spatially (horizontally) integrated (SiDIC) model, was validated with field observations from an estuarine freshwater lake case study. SiDIC reproduce changes daytime nighttime throughout column. Sensitivity tests showed fluctuation controlled suppression due vegetation. results highlight importance resolving vegetation‐induced when modeling budget within coastal environments.

Язык: Английский

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Water temperature dynamics and the prevalence of daytime stratification in small temperate shallow lakes

Hydrobiologia, Год журнала: 2018, Номер 826(1), С. 247 - 262

Опубликована: Авг. 18, 2018

Язык: Английский

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Invasive Aquatic Plants as Ecosystem Engineers in an Oligo-Mesotrophic Shallow Lake

Frontiers in Plant Science, Год журнала: 2018, Номер 9

Опубликована: Дек. 3, 2018

Exotic hydrophytes are often considered as aquatic weeds, especially when forming dense mats on an originally poorly colonized environment. While management efforts and research focused the control impacts of weeds biodiversity, their influence shallow lakes’ biogeochemical cycles is still unwell explored. The aim present study to understand whether invasive plants may affect biogeochemistry lakes act ecosystem engineers. We performed a multi-year investigation (2013–2015) dissolved parameters in oligo-mesotrophic lake south-west France (Lacanau Lake), where wind-sheltered bays by exotic Egeria densa Planch. Lagarosiphon major (Ridl.) Moss. collected seasonal samples at densely vegetated plant-free areas, order extrapolate quantify role presence biogeochemistry, macrophyte stand scale scale. Results revealed that elevated plant biomass triggers oxygen (O 2 ), inorganic carbon (DIC) nitrogen (DIN) stratification, with hypoxia events frequently occurring bottom water column. Within bed, respiration rates generated important amounts dioxide (CO methane (CH 4 ) ammonium (NH + ). balance between benthic nutrients regeneration fixation into results strictly connected lifecycle plants. Indeed, during summer, DIC DIN regenerated from sediment quickly fixed sustain growth rates. On opposite, spring autumn, bacterial overcome fixation, resulting excess increase emission toward atmosphere. Our suggests perform engineers, negatively affecting local oxygenation stimulating regeneration.

Язык: Английский

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Macrophyte-induced thermal stratification in a shallow urban lake promotes conditions suitable for nitrogen-fixing cyanobacteria

Hydrobiologia, Год журнала: 2017, Номер 806(1), С. 411 - 426

Опубликована: Сен. 16, 2017

Язык: Английский

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Sensitivity of the macrophytes Pistia stratiotes and Eichhornia crassipes to hexazinone and dissipation of this pesticide in aquatic ecosystems

Ecotoxicology and Environmental Safety, Год журнала: 2018, Номер 168, С. 177 - 183

Опубликована: Окт. 30, 2018

Язык: Английский

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Shallow plant-dominated lakes – extreme environmental variability, carbon cycling and ecological species challenges

Annals of Botany, Год журнала: 2019, Номер 124(3), С. 355 - 366

Опубликована: Май 13, 2019

Abstract Background Submerged plants composed of charophytes (green algae) and angiosperms develop dense vegetation in small, shallow lakes littoral zones large lakes. Many oligotrophic plant species have declined due to drainage fertilization lakes, while some tall, eutrophic increased. Although distribution has been thoroughly studied, the physiochemical dynamics biological challenges plant-dominated grossly understudied, even though they may offer key persistence. Scope Small function as natural field laboratories with eco-physiological processes dictating extreme environmental variability, intensive photosynthesis carbon cycling. Those can be quantified on a whole lake basis at high temporal resolution by continuously operating sensors for light, temperature, oxygen, etc. We explore this hitherto hidden world. Conclusions Dense canopies attenuate light wind-driven turbulence generate separation between warm surface water colder bottom waters. Daytime vertical stratification becomes particularly strong charophyte vegetation, but is common feature also without plants. Surface cooling night induces mixing column. stands induce hypoxia or anoxia dark waters respiration, oxygen supersaturation photosynthesis. Intensive calcification depletes dissolved inorganic (DIC) waters, whereas DIC replenished respiration carbonate dissolution returned before sunrise. Extreme diel changes extensive rhythmicity become severe challenge survival organisms. Large phosphorus pools are bound tissue precipitates. Future studies should test importance sink ecosystem competition phytoplankton

Язык: Английский

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Integration of Submerged Aquatic Vegetation Motion Within Hydrodynamic Models

Water Resources Research, Год журнала: 2020, Номер 56(8)

Опубликована: Авг. 1, 2020

Abstract Aquatic models used for both freshwater and marine systems frequently need to account submerged aquatic vegetation (SAV) due its influence on flow water quality. Despite importance, parameterizations are generally adopted that simplify feedbacks from SAV, such as canopy properties (e.g., considering the deflected height) bulk friction coefficient. This study reports development of a fine‐scale non‐hydrostatic model demonstrates two‐way effects SAV motion interaction with flow. An object‐oriented approach is applied capture multiphase phenomena, whereby leaf‐scale based discrete element method combined dynamics resolve stresses currents waves. The verified through application laboratory‐scale seagrass bed. A force balance analysis revealed leaf elasticity buoyancy most significant components influencing horizontal vertical momentum equations, respectively. sensitivity canopy‐scale coefficients depth, current speeds, density was explored. Deeper also shown lead smaller decrease in height. can contribute improving assessment processes quality, sediment stabilization, carbon sequestration, restoration, thereby supporting an understanding how waterways coasts will respond changes brought about by changing climate.

Язык: Английский

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