Low Water Level Research Articles

Response of methanogenic community and their activity to temperature rise in alpine swamp meadow at different water level of the permafrost wetland on Qinghai-Tibet Plateau.

Wetlands are an important source of atmospheric methane (CH4) and are sensitive to global climate change. Alpine swamp meadows, accounting for ~50% of the natural wetlands on the Qinghai-Tibet Plateau, were considered one of the most important ecosystems. Methanogens are important functional microbes that perform the methane producing process. However, the response of methanogenic community and the main pathways of CH4 production to temperature rise remains unknown in alpine swamp meadow at different water level in permafrost wetlands. In this study, we investigated the response of soil CH4 production and the shift of methanogenic community to temperature rise in the alpine swamp meadow soil samples with different water levels collected from the Qinghai-Tibet Plateau through anaerobic incubation at 5°C, 15°C and 25°C. The results showed that the CH4 contents increased with increasing incubation temperature, and were 5-10 times higher at the high water level sites (GHM1 and GHM2) than that at the low water level site (GHM3). For the high water level sites (GHM1 and GHM2), the change of incubation temperatures had little effect on the methanogenic community structure. Methanotrichaceae (32.44-65.46%), Methanobacteriaceae (19.30-58.86%) and Methanosarcinaceae (3.22-21.24%) were the dominant methanogen groups, with the abundance of Methanotrichaceae and Methanosarcinaceae having a significant positive correlation with CH4 production (p < 0.01). For the low water level site (GHM3), the methanogenic community structure changed greatly at 25°C. The Methanobacteriaceae (59.65-77.33%) was the dominant methanogen group at 5°C and 15°C; In contrast, the Methanosarcinaceae (69.29%) dominated at 25°C, and its abundance showed a significant positive correlation with CH4 production (p < 0.05). Collectively, these findings enhance the understanding of methanogenic community structures and CH4 production in permafrost wetlands with different water levels during the warming process.

Time-series analysis of Sentinel-1/2 data for flood detection using a discrete global grid system and seasonal decomposition

Automated flood detection using earth observation data is a crucial task for efficient flood disaster management. Current solutions to identify flooded areas usually rely on calculating the difference between new observations and static, pre-calculated water extents derived by either single acquisitions or timely aggregated products. Such pre-calculated datasets, however, lack representation of real-world seasonality and short-term changes in trend. In this paper we present a complete workflow to automatically detect hydrological extreme events and their spatial extent, which automatically adapts to local seasonality and trend. For that we rely on a novel combination of well-established algorithms and tools to detect anomalies in time-series of water extent across large study areas. The data is binned into a discrete global grid system H3, which greatly simplifies aggregation across spatial and temporal resolutions. For each grid cell of an H3 resolution we perform a time-series decomposition using Seasonal and Trend decomposition using Loess (STL) of the cell’s proportion which is covered with surface water. All cells receive an anomaly score, calculated with extended isolation forest (EIF) on the residuals for each step in time. A burst of anomalies represents a hydrological extreme event like a flood or low water level. The presented methodology is applied on Sentinel-1/2 data for two study areas, one near Sukkur, Pakistan and the other one in Mozambique. The detected anomalies correlate with reported floods and seasonal variations of the study areas. The performance of the process and the possibility to use different H3 resolutions make the proposed methodology suitable for large scale monitoring.

The influence of extreme water levels on coastal wetland extent across the Laurentian Great Lakes

Laurentian Great Lakes coastal wetlands (GLCW) are ecological hotspots and their integrity depends upon dynamic hydrologic regimes of the Great Lakes. GLCW naturally adjust to changes in hydrologic regimes via migration, but Great Lakes water levels may be shifting faster than wetlands can manage: 2000–2015 marked an extended low water level period and was followed by record highs in 2017–2020. Our objective was to quantify how Great Lakes water levels impact GLCW linear extent (from the shoreline to open water). We calculated wetland extent and migration from 2011 to 2019 using data from 1538 vegetation transects at 342 sites across the U.S. shoreline of the Great Lakes. Mediated multiple linear regression with Bayesian hierarchical modeling investigated the relationship between water levels and wetland extent. We employed Bayesian hierarchical modeling because (1) the dataset was spatially nested, with sampling points within wetlands within Great Lakes and (2) Bayesian statistics offer flexibility for environmental modeling, such as the inclusion of mediation in models, where we can assess both direct influences of Great Lake water levels on wetland extent and indirect (i.e., mediated) influences of water levels via the presence of vegetation zones on thus wetland extent. Results showed that, overall, there was a landward migration from 2011 to 2019 (although 38 % of wetlands had lakeward migration of the wetland-upland border). Wetland length and inundation length decreased with increased water levels, as mediated by the presence of certain vegetation zones. This decrease in wetland extent is of concern because it likely relates to a decrease in wetland function and habitat. A better understanding of how GLCW migrate with shifts in water levels enables decision makers to better predict where Great Lakes coastal wetlands are at risk of being lost and thus where to prioritize management efforts.

Combining ground stability investigation with exploratory drilling for mine water geothermal energy development; lessons from exploration and monitoring

Mine water geothermal energy's potential for decarbonization of heating and cooling in the UK has led to increased national interest and development of new projects. In this study, mine water geothermal exploration has been coupled with ground investigation techniques to assess ground stability alongside seasonal mine water hydrogeology and geochemistry. Drilling operations in late 2020 at Dollar Colliery, Clackmannanshire, Scotland, encountered mined coal seams with varying conditions (void, intact, waste, etc.), reflecting different techniques used throughout a protracted mining history. We found that time and resources spent grouting casing through worked mine seams (ensuring hydraulic separation) can be saved by accessing deeper seams where those above are unworked. Continued assessment of existing water discharges and completion of boreholes with slotted liners into mined coal seams and fractured roof strata allowed chemical and water level changes to be monitored across a 1 year period. Mine water heads and mine discharge flow rates vary seasonally and are elevated between late autumn and early spring. The mine water has a low dissolved solute content. Dissolved sulfate- 34 S isotope data suggest increased pyrite oxidation during lower water levels. These findings can inform future building decisions, whereby housing developments on site could use the mine water for heating. Supplementary material: Borehole data and completion diagrams are available at https://doi.org/10.6084/m9.figshare.22188801 Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/topic/collections/early-career-research

Modern hydrological characteristics of the Kuibyshev reservoir as a basis for the development of water bioresources

THE PURPOSE. Consider the indicators of the operation mode of the Kuibyshev reservoir over the past 15 years, affecting the state of the fish stock; identify the main trends in changes in water volumes in the reservoir due to climate change, the features of the level regime for the ecological solution of the problem of preserving aquatic biological resources.METHODS. A comparative analysis of our own research and literature data on the hydrological characteristics of the Kuibyshev reservoir, the temperature regime of the region and the state of the ichthyofauna was carried out. In this work, to analyze the current state of the hydrological regime, data provided by the Verkhniy Byef gauging station of the branch of JSC RusHydro - Zhigulevskaya HPP and the State Committee of the Republic of Tatarstan for Biological Resources were used.RESULTS. It is shown that the average water level in the Kuibyshev reservoir for the last period ranged from 50.34 to 52.31 m at NHL - 53.00 m BS, DVL - 45.5 m. Based on the totality of characteristics in terms of average water levels and inflows, 2010, 2011, 2021 can be attributed to low-water years, 2007-2009, 2012-2020 to years with average water content, and there were no high-water years during this period.The analysis of the dynamics of changes in the maximum and minimum water levels was carried out and changes were identified: the minimum recorded water level (48.16 m) was noted in January (2011), at the end of the 20th century, the minimum levels were recorded in March - April and they were lower by 1-1, 5 m in summer drawdown and 2.5 - 3.5 m in winter, the level rise occurs in April, while earlier it was in May. The duration of the high-water period (about 53 m) increased to 4 months. The minimum volume in the reservoir was recorded in the winter period of 2010-2011 - 36.14 km3, the maximum volume is 57.66 km3 in the winter period of 2019-2020. Maximum water discharges are carried out mainly in the second half of April and early May. Minimum discharges are carried out in different periods.It is shown that the number of days with an air temperature above 15°C, which characterizes the fishery zone, varies in different years of the last period from 71 days (2017) to 133 days (2020).CONCLUSION. A relative increase in temperature was noted as the most important environmental factor for the development of aquatic bioresources; currently, the process of accelerating eutrophication of shallow areas of the Kuibyshev reservoir is observed. The regular death of fish in different parts of the reservoir, combined with factors such as low water levels and high temperatures, creates the preconditions for “local catastrophes” at the level of ichthyocenoses, the area of “local catastrophes” is expanding due to climate change. The mortality of fish is a mechanism for the release of the ecosystem from excess organic matter, and the mortality of a small particle indirectly indicates a high abundance of low-value and weedy fish, the number of which must be reduced.

Effect of climate change-induced water-deficit stress on long-term rice yield.

The water requirements of crops should be investigated to improve the efficiency of water use in irrigated agriculture. The main objective of the study was to assess the effects of water deficit stress on rice yields throughout the major cropping seasons. We analyzed rice yield data from field experiments in Taiwan over the period 1925-2019 to evaluate the effects of water-deficit stress on the yield of 12 rice cultivars. Weather data, including air temperatures, humidity, wind speed, sunshine duration, and rainfall were used to compute the temporal trends of reference evapotranspiration and crop water status (CWS) during rice growth stages. A negative CWS value indicates that the crop is water deficient, and a smaller value represents a lower water level (greater water-deficit stress) in crop growth. The CWS on rice growth under the initial, crop development, reproductive, and maturity stages declined by 96.9, 58.9, 24.7, and 198.6 mm in the cool cropping season and declined by 63.7, 18.1, 8.6, and 3.8 mm in the warm cropping season during the 95 years. The decreasing trends in the CWSs were used to represent the increases in water-deficit stress. The total yield change related to water-deficit stress on the cultivars from 1925-1944, 1945-1983, and 1996-2019 under the initial, crop development, reproductive, and maturity stages are -56.1 to 37.0, -77.5 to -12.3, 11.2 to 19.8, and -146.4 to 39.1 kg ha-1 in the cool cropping season and -16.5 to 8.2, -12.9 to 8.1, -2.3 to 9.0, and -9.3 to 8.0 in the warm cropping season, respectively. Our results suggest that CWS may be a determining factor for rice to thrive during the developmental stage, but not the reproductive stage. In addition, the effect of water-deficit stress has increasingly affected the growth of rice in recent years.

Effects of microtopography on soil development of the conserved area in the Isahaya Bay polder

ABSTRACT After reclamation of the Isahaya Bay polder, a conserved area is covered with naturally developed vegetation under high groundwater level conditions. This study investigated how alluvial deposits transform into soil without utilizing artificial water drainage systems for agricultural land uses. Soils were surveyed under four vegetation compositions, including those dominated by goldenrods (GR), occupied by high-grown reeds (HRD), covered with low-grown reeds (LRD), or a mixture of goldenrods and reeds (MIX). The microtopography of the polder differentiated the research site with a higher elevation at the GR location, followed by a MIX, HRD, and a lower elevation at the LRD location. The soils were characterized by their physicochemical properties and ionic composition of the soil water. Electrical conductivity (EC), which can be an indicator of residual seawater, was lowest in the GR, followed by the MIX, HRD, and LRD. The soil moisture regimes affected by microtopography led to different frequencies of wet-dry cycles in the soil, resulting in a developing sequence of soil structure from LRD to GR with decreasing EC. The ionic composition of soil water varied with elevation and soil depth. The residual seawater still influenced the ionic composition of deeper soil horizons at lower elevations, while specifically high rates of Ca2+ and SO4 2− were observed in GR. The oxidation of pyrite is stimulated by soil aeration with lowering water level, resulting in soil acidification and the simultaneous dissolution of calcium carbonate from seashells. The sequential changes in soil properties with elevation indicated the effects of microtopography on soil moisture dynamics, which led to variations in soil formation and vegetation in the conserved area.

Oil-Based Sanitization in Low-Moisture Environments: Delivery of Acetic Acid with Water-in-Oil Emulsions.

Contamination with Salmonella spp. and Listeria monocytogenes is concerning across low-moisture food (LMF)-processing environments due to the pronounced survival of these organisms under dry conditions. This study treated desiccated bacteria with acetic acid delivered by oil with and without water-in-oil (W/O) emulsion. The influences of cellular desiccation, emulsion water concentration, water activity (aw), and treatment temperature were investigated. Acetic acid dissolved in oil (i.e., acidified oil) showed low levels of antimicrobial efficacy. After treatment with acidified oil (200 mM acetic acid at 22°C for 30 min), Salmonella enterica serovar Enteritidis phage type 30 cells desiccated to 75% equilibrium relative humidity (ERH) and 33% ERH were reduced by 0.69 and 0.05 log CFU/coupon, respectively. The dispersion of a low level of water (≥0.3%, vol/vol) within the acidified oil with the surfactant (i.e., acidified W/O emulsion) significantly enhanced the antimicrobial efficacy. After treatment with the acidified W/O emulsion (200 mM acetic acid at 22°C for 20 min), desiccated Salmonella (4-strain cocktail) and L. monocytogenes (3-strain cocktail) cells were reduced by >6.52 log most probable number (MPN)/coupon, regardless of the desiccation levels. Increased efficacy was observed with temperature elevation. Reduced efficacy was observed when glycerol was added to the aqueous phase of the emulsion to decrease the solution aw, indicating that the enhanced efficacy of the acidified W/O emulsion was associated with differential osmotic pressure. The antimicrobial mechanism may be due to the membrane disruption induced by acetic acid, in combination with the hypoosmotic stress provided by W/O emulsion, creating cellular lysis, as illustrated by electron micrographs. IMPORTANCE Aqueous-based cleaning and sanitation are undesirable in processing facilities that manufacture low-moisture foods such as peanut butter and chocolate. Alcohol-based sanitization is advantageous because it leaves no residue on the contact surface but requires the processing facility to close temporarily due to flammability. At >6.52 log kill of desiccated Salmonella and Listeria monocytogenes cells, the developed oil-based formulation has the potential to be an effective dry sanitation method.

Study on Analysis Method and Control Index for Deformation of Super-High Arch Dam Suffering Alkali-Aggregate Reaction

Alkali-aggregate reaction can not only cause uneven expansion of concrete but also lead to cracking and even destruction and consequently affect the working behavior and long-term safety of hydraulic concrete structures. Present researches on alkali-aggregate reaction focus on improving the composition ratio of concrete materials through experimental study to inhibit the reaction, whereas there is a lack of quantitative calculation and analysis. In the present study, the problem of alkali-aggregate reaction in the super-high arch dam of Jinping I Hydropower Station was taken as an example. The expansion of concrete suffering the alkali-aggregate reaction was simulated by means of the overall temperature rise in the dam. Similarly, the yield zone, the expansion process, and the deformation change law with the development of concrete expansive deformation under various load combinations were analyzed by using the elastic–plastic finite element method. Finally, a control index of allowable alkali-aggregate expansion of dam concrete under various load combinations was put forward. The research results demonstrated that the control index was 400~800 με. Since the arch dam has a low safety reserve when operating at a low water level, the lowest reservoir level should be raised as much as possible in dam operation to reduce its drawdown rate, thus restraining the adverse impact of alkali-aggregate reaction in concrete on the dam.

Peak Water Levels Rise Less Than Mean Sea Level in Tidal Channels Subject to Depth Convergence by Deepening

AbstractEffects of sea‐level rise (SLR) on future peak water levels in tidal deltas and estuaries are largely unknown, despite these areas being densely populated and at high risk of flooding. While the rates of SLR accelerate, many channels simultaneously experience channel deepening for navigation. With globally decreasing sediment supplies, most channels are at risk of becoming deeper when the rate of SLR accelerates and sedimentation cannot keep pace with SLR. These factors potentially favor amplification of the tides and thereby increase flood risk, but the extent to which they will do so is unknown. Here, we introduce and use a validated model for an artificially deepened multi‐branch delta to get a mechanistic understanding of non‐linear SLR‐effects on peak water levels. Results show that, when the current deepened bed level will be maintained, peak water levels do not rise on par with mean sea‐level. Thus flood risk increases less than what can be expected from the predictions of the mean sea‐level increase. The reason is that SLR causes a proportional reduction in convergence of channel area. This mechanism reduces tidal amplification. Nevertheless, SLR effects extend far beyond the range of present‐day seasonal variations, with future low water levels being equal to present‐day high water levels, while the tidal range slightly reduces. This will have consequences not only for flood risk, but also for freshwater availability, navigation and ecology.

Differences in Growth Pattern in Two Freshwater Fish Species (Leuciscidae) During Summer Drought in North-West Italy

Abstract This study aim is to assess how the water shortage impacted on the growth of two endemic freshwater fish species, the Italian riffle dace Telestes muticellus (Bonaparte, 1837) and Phoxinus spp. complex, in a pre-alpine area in North-West Italy. Both species’ specimens growth depended on the streamflow rate: in particular low water levels weighted on Phoxinus spp. specimens, since they showed a negative growth pattern during dry months, while the Telestes muticellus ones continually had a positive growth pattern in the same time frame. The streamflow rate plays a key role in fish growth during severe drought in this area but mechanisms that allow Telestes muticellus specimens to outcompete Phoxinus spp. ones throughout water shortage periods are still unknown.

Flooding mitigation through safe & trustworthy reinforcement learning

Reinforcement learning (RL) has been used in real-time control of urban drainage system (UDS) for flooding mitigation, achieving a milestone in urban water management. However, RL can only guarantee an optimization control, rather than keep the control trajectory safe and trustworthy. Therefore, unacceptable risk still exists when handing over the real-world control process to an RL agent. Although safe learning is effective in enhancing RL’s safety, it cannot be applied directly due to the lack of quantitative framework of RL’s safety in UDS context. This study conducts three tasks to investigate and improve the safety of RL in UDS. First, a metric framework of RLs’ safety in the context of UDS is provided through a mathematic description. Then, it is plugged into safe learning methods to improve RLs’ safety in UDS. After that, a systemic uncertainty analysis is employed to evaluate the robustness of RL. The results of the case study indicate that (i) all the RLs show a promising result in flooding mitigation; (ii) safe learning helps RLs achieve a safer control process with a lower average water level and lower frequency of orifices operation; (iii) the robustness of RLs in UDS is influenced by the volume of rainfalls, the degree of randomness, and the type of RLs.

Relationships between the tide and fatal drowning at surf beaches in New South Wales, Australia: Implications for coastal safety management and practice

Beaches are popular, recreational destinations, but can be hazardous environments where drowning fatalities and other types of injuries can occur. Ocean lifeguards and beach safety managers make operational safety decisions based on ocean conditions, including various elements of the tide. This study addresses assumptions about the tide that are common in beach safety management; assessing the scientific basis that informs these decisions by evaluating the relationship between elements of the tide and fatal drowning on microtidal surf beaches in New South Wales (NSW), Australia. Lower tidal water levels and time periods closer to low tide were associated with increased likelihood of fatal drowning at surf beaches, while tidal phase (rising vs falling), tide range, and the rate of change of falling or rising water levels were not. These results have implications for ocean safety management and those responsible for educating the public about beach safety issues. Broad statements or anecdotal opinions that are not location or beach-specific should avoid describing times with falling water levels (an outgoing tide) as being inherently more dangerous.

Exploring the Research Challenges and Perspectives in Ecophysiology of Plants Affected by Salinity Stress

Soil salinization processes have increased over the years and affect large parts of agricultural fields. The purpose of this review was to highlight the most important aspects regarding the potential effects of soil salinity on plants. In the current context of climate change, extreme weather and increased drought periods can lead to plant metabolic dysfunctionalities and accumulation of salt ions because of the increasing need for irrigation. The most important limiting factor, salinity, has a highly negative impact on plant growth independent of the appearance of either natural or anthropic status. The negative aspects include decreased leaf development rate, a low water level in all parts of the plant, reduced cell division and elongation, and low-intensity photosynthetic rate. Other negative aspects are directly related to stomata closure, reduced transpiration, low CO2 level, and limitations on seed germination. However, there are also some positive aspects to the presence of salinity in soil. The field offers unlimited possibilities of research in order to activate pathways that help plants become resistant to salt stress. Several physiological parameters can benefit from low salt concentration (halopriming), such as germination, vigor, rapid seedling growth, and increased stomata number. Further studies should focus on both the positive and negative aspects of the increase in soil salinity.

Extreme Weather Events and Economic Activity: The Case of Low Water Levels on the Rhine River

Abstract We make use of historical data on water levels on the Rhine river to analyze the impact of weather-related supply shocks on economic activity in Germany. Our analysis shows that low water levels lead to severe disruptions in inland water transportation and cause a significant and economically meaningful decrease of economic activity. In a month with 30 days of low water, industrial production in Germany declines by about 1 percent, ceteris paribus. Our analysis highlights the importance of extreme weather events for business cycle analysis and contributes to gauging the costs of extreme weather events in advanced economies.

Does the multi-proxy Eemian record from the Słup site (central Poland) indicate a more humid climate at the beginning of the hornbeam phase?

A new site of Eemian organogenic deposits in S3up (central Poland) has revealed an intermittent record of several phases within this interglacial. Pollen based studies of the core S3-19, drilled at the littoral zone of the palaeolake, indicated the absence of the E2, E3, E6 and an incomplete record of the E4 and E5 zones of the typical pollen succession. Results of other proxies (plant macrofossils, Cladocera, molluscs, NPPs, isotopes) supported the conclusions derived from the pollen diagram regarding the high humidity and lake water level during the E4 (Corylus-Quercus-Tilia) phase and at the beginning of the E5 (Carpinus-Corylus-Alnus) phase, when the fossil lake was most extensive. Thus, the lack of a record of the E3 and E4 RPAZs was associated with water level lowering and a less humid climate. The results stand in agreement with several other Eemian records from central Poland.

Detection of changes in the hydrobiological parameters of the Oder River during the ecological disaster in July 2022 based on multi-parameter probe tests and remote sensing methods

Starting from the second half of July, hydrological conditions (low water levels and low flows) and atmospheric conditions (high temperatures, lack of precipitation) contributed to algae bloom in the Oder River basin. The mass extinction of fish in the middle and lower section of the Oder was probably the result of such environmental conditions. Because algae bloom is correlated with an increase in the content of chlorophyll in the river and on its surface, the authors focused on an analysis of changes in the chlorophyll amount in the longitudinal profile of the river. The key data was obtained by soundings carried out at an interval of about one kilometre during the research expedition, which took place on July 16–24, 2022. These data coincided with the values of the NDVI index (normalised difference vegetation index) based on 10-metre satellite images from the Sentinel 2 mission. Imagery from cloudless periods (mainly March, June, July and August) processed using the NDVI index was compared. Regularly elevated chlorophyll levels in the upstream section (occurring in each period) and temporarily elevated chlorophyll values as moving downstream were observed. This article confirms the initial conclusions of Kolada et al. (2022) that the mass fish kill in the Oder River in the summer of 2022 was conditioned by natural environmental pressure causing massive algae bloom and the release of their toxins. The article also proves that the use of satellite images for this type of analysis is the correct approach, but due to low resolution, they cannot be used as reference material. Changes in the hydrobiological parameters of the river, which are a direct indicator of the causes of the ecological disaster, are the data of the multi-parameter probe obtained two weeks before the first mass catches of dead fish.

A Statistical Analysis of the Water Levels at Lake Neusiedl

The recent low water levels of Lake Neusiedl have raised concern about the lake's future and have sparked interest on how meteorological variables impact the water level. Data from the last 50 years are used to study the impact of rain and temperature on the cyclical changes of the water levels. Linear and nonlinear regression models are used to describe how rainfall and temperature change the water level, and to assess the future progression of the water level under three scenarios. For average 2022 meteorological conditions the water levels in 2022 may not recover for a dry 2021 autumn, but will recover substantially for a wet ending to the year 2021.

Production in peatlands: Comparing ecosystem services of different land use options following conventional farming

Majority of Dutch peatlands are drained and used intensively as grasslands for dairy farming. This delivers high productivity but causes severe damage to ecosystem services supply. Peatland rewetting is the best way to reverse the damage, but high water levels do not fit with intensive dairy production. Paludiculture, defined as crop production under wet conditions, provides viable land use alternatives. However, performance of paludiculture is rarely compared to drainage-based agriculture. Here, we compared the performances of six land use options on peatland following a gradient of low, medium, and high water levels, including conventional and organic drainage-based dairy farming, low-input grasslands for grazing and mowing, and high-input paludiculture with reed and Sphagnum cultivation. For each land use option, we conducted environmental system analysis on model farm system defined by a literature based inventory analysis. The analysis used five ecosystem services as indicators of environmental impacts with a functional unit of 1-ha peat soil. Ecosystem services included biomass provisioning, climate, water, and nutrient regulation, and maintenance of habitat. Results showed that drainage-based dairy farming systems support high provisioning services but low regulation and maintenance services. Organic farming provides higher climate and nutrient regulation services than its conventional counterpart, but limited overall improvement due to the persistent drainage. Low-intensity grassland and paludiculture systems have high regulation and maintenance services value, but do not supply biomass provisioning comparable to the drainage-based systems. Without capitalizing the co-benefits of regulation and maintenance services, and accounting for the societal costs from ecosystem disservices including greenhouse gas emission and nitrogen pollution, it is not likely that the farmers will be incentivized to change the current farming system towards the wetter alternatives. Sustainable use of peatlands urges fundamental changes in land and water management along with the financial and policy support required.

Strong temporal variation of consumer δ13C value in an oligotrophic reservoir is related to water level fluctuation

Using stable carbon and nitrogen isotope analysis (δ13C and δ15N) to assess trophic interactions in freshwater ecosystems is a well established method, providing insight into ecosystem functioning. However, the spatial and temporal variability of isotope values, driven by environmental fluctuation is poorly understood and can complicate interpretations. We investigated how the temporal variation of stable isotopes in consumers (fish, crayfish and macrozoobenthos) of a canyon-shaped oligotrophic reservoir is associated with environmental factors such as water temperature, transparency, flooded area, and water quality measures. Consumers and their putative food sources were sampled and analyzed for carbon and nitrogen stable isotopes annually, and environmental parameters were measured monthly from 2014 to 2016. Results revealed significant differences in δ13C and δ15N values in each consumer among studied years. Over the years, fish and crayfish expressed differences in δ13C between 3 and 5‰, whereas in zoobenthos differences were 12‰. Variability in δ15N was similar across all consumers (2–4‰). Moreover, results suggest that the flooded area of the reservoir was a major driver of δ13C stable isotope values variation in consumers, while variation in δ15N was not linked to any of the studied environmental factors. Bayesian mixing models further showed significant changes in the origin of detritivorous zoobenthos carbon sources (reversal shift from terrestrial detritus to algae origin) between years with low water level to years with the standard water level. Other species showed only slight differences in food source utilization among years. Our study highlights the importance of environmental factors as sources of variation in consumer’s stable isotope values which should be considered especially when studied ecosystem strongly fluctuate in some environmental factor.