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Phosphorus (P) precipitation is among the most effective treatments to mitigate lake eutrophication. However, after a period of high effectiveness, studies have shown possible re-eutrophication and the return of harmful algal blooms. While such abrupt ecological changes were attributed to the internal P loading, the role of lake warming and its potential synergistic effects with internal loading, thus far, has been understudied. Here, in a eutrophic lake in central Germany, we quantified the driving mechanisms of the abrupt re-eutrophication and cyanobacterial blooms in 2016 (30 years after the first P precipitation). A process-based lake ecosystem model (GOTM-WET) was established using a high-frequency monitoring data set covering contrasting trophic states. Model analyses suggested that the internal P release accounted for 68% of the cyanobacterial biomass proliferation, while lake warming contributed to 32%, including direct effects via promoting growth (18%) and synergistic effects via intensifying internal P loading (14%). The model further showed that the synergy was attributed to prolonged lake hypolimnion warming and oxygen depletion. Our study unravels the substantial role of lake warming in promoting cyanobacterial blooms in re-eutrophicated lakes. The warming effects on cyanobacteria via promoting internal loading need more attention in lake management, particularly for urban lakes.

We studied the quantitative composition, spatial distribution, and temporal dynamics of the zooplankton community of the alpine Lake Sevan, Armenia, the largest surface water in the Caucasus region. This article is providing a long-term information and fills the research gap of multiyear data on zooplankton, as the previous research on zooplankton provided only snapshots of the community, and a consistent assessment over multiple years was missing. However, an initial mini-review of historical studies indicated that zooplankton biomass and fish abundance were undergoing large fluctuations, indicating the importance of top-down control. We analysed 239 samples from the period 2016-2019 from 32 sampling sites in Lake Sevan and recorded 37 species of meso- and macrozooplankton (Rotifers, Copepods, Cladocera). Biomass fluctuations were high with peaking biomasses in 2016 and lowest biomasses in 2018, yearly averaged biomass varied about one order of magnitude. Variability over time was hence much higher than spatial variability. The pelagic habitat at the deepest part of the lake showed the highest diversity and biomasses but contrasts between sampling sites remained smaller than changes from year to year or seasonally. Many samples were dominated by a single species, and these key species explain observed biomass dynamics to a wide extent. We applied hierarchical clustering in order to identify phenological groups that appear to show similar patterns of occurrence. This clustering resulted in 6 groups where of 5 groups just consisting of one single species and these 5 key species were the Cladocerans Daphnia magna, Daphnia hyalina, Diaphanosoma sp. as well as the calanoids Arctodiaptomus bacillifer and Acanthodiaptomus denticornis. The most important species in Lake Sevan’s zooplankton during the observation period was D. magna, which reached high biomasses in 2016 and 2017 but then suddenly almost disappeared in 2018 and 2019. When there were more D. magna present, th

Lake Sevan is the largest freshwater lake in the Caucasus region and one of Eurasia's largest alpine lakes. The lake has been experiencing growing cyanobacteria blooms; however, the relevance of external and internal phosphorus (P) loading to its eutrophication is still not known. We carried out a sediment investigation of Lake Sevan to estimate the potentially mobile P, which could be a source of internal total phosphorus (TP)-loading; we also estimated external TP-loading and retention. The study was carried out at four sampling points of different depths to determine the spatial variability of P in 2018. The sediments had elevated TP contents at the sediment surface; potentially mobile P ranged from 20 to 60% in the top 2 cm. The upper 4 cm sediment had an elevated content of TN (8 to 16.1 mg N g-1 dw) and TP (1.2 to 1.7 mg P g-1 dw). Spatial variability of most of the measured parameters was more prominent in the upper 3 cm. External TP loading was estimated to be 110 tons annually, and the TP retention was 85%. The estimated TP stored in the top cm of the sediment is 1,500 tons. The potential for P release is high; the short-term exchange between oxic and anoxic overlying water could release 0.01 to 0.02 mg P L-1 from the top cm of the sediment, and long-term diagenesis and burial could release about 0.12 mg P cm-2. Internal P-loading in Lake Sevan may play an essential role in eutrophication, especially given the long flushing time of Lake Sevan.

Lake Sevan, a large, deep, alpine lake in the Lesser Caucasus is the focus of this Special Issue of the Journal of Limnology. It was an outstanding ecosystem 100 years ago characterised by excellent water quality, rich biodiversity with a high level of endemism, wide-ranging beds of macrophytes along the shores and a productive and sustainable fish production. Due to its beauty, natural history, and contributions to social and economic welfare it is also a cultural heritage for the Armenian Nation including its large diaspora.

Phosphorus (P) precipitation is among the most effective treatments to mitigate lake eutrophication. However, after a period of high effectiveness, studies have shown possible re-eutrophication and the return of harmful algal blooms. While such abrupt ecological changes were attributed to the internal P loading, the role of lake warming and its potential synergistic effects with internal loading, thus far, has been understudied. Here, in a eutrophic lake in central Germany, we quantified the driving mechanisms of the abrupt re-eutrophication and cyanobacterial blooms in 2016 (30 years after the first P precipitation). A process-based lake ecosystem model (GOTM-WET) was established using a high-frequency monitoring data set covering contrasting trophic states. Model analyses suggested that the internal P release accounted for 68% of the cyanobacterial biomass proliferation, while lake warming contributed to 32%, including direct effects via promoting growth (18%) and synergistic effects via intensifying internal P loading (14%). The model further showed that the synergy was attributed to prolonged lake hypolimnion warming and oxygen depletion. Our study unravels the substantial role of lake warming in promoting cyanobacterial blooms in re-eutrophicated lakes. The warming effects on cyanobacteria via promoting internal loading need more attention in lake management, particularly for urban lakes.

Lake Sevan (Armenia) is one of the large freshwater high-mountain lakes of Eurasia. Detailed information about the extent and fate of trace elements on lake sediment and water quality has not been published yet. For this reason, surface sediment and water samples were collected from the southern and northern basins of Lake Sevan to determine trace element concentrations and assess the trace element behaviour. Geo-accumulation index, potential ecological risk index, and hazard index were calculated to estimate the environmental risk potential. In comparison to reference values, the investigated sediment samples contained elevated concentrations frequently for V, Cr, Co, Ni, Mo, Cd, Be, Ti, Rb, Sr, Se, Hf, and Th and occasionally for Cu, As, Li, B, Ag, Sb, Tl, Bi, U, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm. An overall potential ecological risk posed by all the investigated trace elements in the sediments was assessed to be moderate-considerable, however, Mo, Hg, and Cd were the elements with the highest ecological risk potential. The two basins of the lake showed significantly different behaviour according to the investigated trace element contents in the sediments to be higher in the bigger basin compared to the smaller basin. In comparison to reference concentrations in water samples according to the use of the adapted geo-accumulation index, elevated values for Ti, Cr, Cu, Cd, and Pb were observed. Elevated concentration was also observed in the case of B in nearly all water samples in comparison with literature values. Nevertheless, several water samples can be seen as not strongly anthropogenic influenced by Co, Ni, Sn, Sb, Ag, Hg, and Bi. The concentrations of trace elements in the lake water caused health risks to humans particularly children in the case of lake water used for drinking purposes, moreover, As was the main element posing health hazards. The results point out further attention to the sources of elevated trace elements in Lake Sevan, inc

How climate change will affect reservoirs and potential adaptation strategiesClimate change is strongly affecting lakes and reservoirs worldwide and climate modellers provide detailed information on different trajectories of future climates enfolding warming rates between ca. 2K (optimistic scenario RCP2.6) and 6K (pessimistic scenario RCP8.5) until 2100. Although these predictions provide insights into future conditions it is often difficult for practitioners to translate this climate information into applicable knowledge for their management. This is also true for reservoir managers who have to balance many different aspects at the same time (e.g. reservoir purpose, local specialities or technical specifications). Appropriate impact model tools therefore require to acount for local features and require rigorous validation and uncertainty assessment. We demonstrate such a translation process by linking impact models (reservoir model CEQUAL & catchment model mHM) to climate forecasts for Germany’s largest drinking water reservoir (Rappbode reservoir) in order to identify problematic developments and potential solutions.

The Marine Strategy Framework Directive (MSFD) Technical Group on Marine Litter developed the on monitoring of marine litter in European s in 2013 to enable EU Member States to launch monitoring programmes for MSFD Descriptor 10: no harm caused by marine litter . The maturity of methodological protocols for marine litter monitoring has increased over the last 10 years, based on research advances and M efforts.This document updates the previous guidance to facilitate the harmonisation of the monitoring framework for the MSFD, including protocols, recommendations, and information required to increase the comparability of data and assessments among Member States. The document comprises chapters dedicated to the protocols for monitoring marine litter across different marine environmental compartments (i.e. the coastline/beach, the surface layer of the water column, the seafloor/seabed) and types of litter (i.e. macro litter, mesolitter, microlitter, ingested litter and microlitter by biota, and entanglement with litter).

Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from or transmission through a magnetic sample, were discovered over a century and a half ago. Initially they played a crucially relevant role in unveiling the fundamentals of electromagnetism and quantum mechanics. A more broad-based relevance and wide-spread use of MO methods, however, remained quite limited until the 1960s due to a lack of suitable, reliable and easy-to-operate light sources. The advent of Laser technology and the availability of other novel light sources led to an enormous expansion of MO measurement techniques and applications that continues to this day (see section 1). The here-assembled roadmap article is intended to provide a meaningful survey over many of the most relevant recent developments, advances, and emerging research directions in a rather condensed form, so that readers can easily access a significant overview about this very dynamic research field. While light source technology and other experimental developments were crucial in the establishment of today's magneto-optics, progress also relies on an ever-increasing theoretical understanding of MO effects from a quantum mechanical perspective (see section 2), as well as using electromagnetic theory and modelling approaches (see section 3) to enable quantitatively reliable predictions for ever more complex materials, metamaterials, and device geometries. The latest advances in established MO methodologies and especially the utilization of the MO Kerr effect (MOKE) are presented in sections 4 (MOKE spectroscopy), 5 (higher order MOKE effects), 6 (MOKE microscopy), 8 (high sensitivity MOKE), 9 (generalized MO ellipsometry), and 20 (Cotton–Mouton effect in two-dimensional materials). In addition, MO effects are now being investigated and utilized in spectral ranges, to which they originally seemed completely foreign, as those of synchrotron radiation x-rays (see section 14

We predicted that chronic pain patients have a more negative stress mindset and a lower level of social identification than people without chronic pain and that this, in turn, influences well-being through less adaptive coping. 1240 participants (465 chronic pain patients; 775 people in the control group) completed a cross-sectional online-survey. Chronic pain patients had a more negative stress mindset and a lower level of social identification than people without chronic pain. However, a positive stress mindset was linked to better well-being and fewer depressive symptoms, through the use of the adaptive coping behaviors positive reframing and active coping. A higher level of social identification did not impact well-being or depression through the use of instrumental and emotional support coping, but through the more frequent use of positive reframing and active coping. For chronic pain therapy, we propose including modules that foster social identification and a positive stress mindset.

Pit lakes may present significant risks to ecological and human receiving environments but can also provide beneficial end use opportunities. The understanding of many processes that influence the magnitude of these risks and opportunities remains limited, and even where our understanding is adequate, the application of that knowledge is not consistently applied. From initial planning to long-term closure, regulation and corporate management of pit lake closure can be improved to realise more sustainable pit lake legacies. In this two-part manuscript, we recommend focus areas for future research by academics (Part 1), and strategies to structurally improve the practice of pit lake closure for mining industry regulators, corporate sustainability officers, global practice leads, and site mine closure planners (Part 2). Here we identify barriers that often limit the understanding of pit lake processes and closure practices and suggest ways that corporate leaders, closure practitioners, and regulators can improve pit lake management. Recommended corporate changes include: conducting risk assessments at an early planning stage; funding pit lake research and trials; allowing data sharing and case study publication; avoiding the simplifying assumption of a fully mixed pit lake when making predictions; integrating climate change into pit lake predictions; improving the quality of technical reporting; generating industry guidance for pit lake rehabilitation; maximizing opportunities for subaqueous, in-pit disposal of mine wastes; creating a positive legacy through beneficial uses of pit lakes; and verifying predictions using long-term monitoring. Recommended regulatory advancements include: raising expectations of corporate pit lake closure planning and execution; acknowledging good pit lake closure examples; balancing the need to simulate long closure periods with expectations of model reliability; considering the value of pit lakes as future water resources during permitti

The resilience of natural systems may be severely compromised by anthropogenic influences. In this paper, the principal anthropogenic influences on the ecosystem of the Armenian highland lake Sevan during the past century are identified. The diversity and severity of the pressures were influenced by national priorities and the catchment's growth. Changes in the lake's morphometry and the littoral's morphology, as well as unsustainable usage of the lake's fish resources, were among the repercussions. They are discussed depending on how each sort of disturbance affects the ecosystem. Although the timing and degree of each stressor were specified, identifying the direct effects of each stressor was often challenging. The current management decisions and future threats to the lake's ecosystem are discussed. This article describes the history of the anthropogenic change of Lake Sevan and, using it as an example, assesses the ecological footprint of people on natural resources and their repercussions.

Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from or transmission through a magnetic sample, were discovered over a century and a half ago. Initially they played a crucially relevant role in unveiling the fundamentals of electromagnetism and quantum mechanics. A more broad-based relevance and wide-spread use of MO methods, however, remained quite limited until the 1960s due to a lack of suitable, reliable and easy-to-operate light sources. The advent of Laser technology and the availability of other novel light sources led to an enormous expansion of MO measurement techniques and applications that continues to this day (see section 1). The here-assembled roadmap article is intended to provide a meaningful survey over many of the most relevant recent developments, advances, and emerging research directions in a rather condensed form, so that readers can easily access a significant overview about this very dynamic research field. While light source technology and other experimental developments were crucial in the establishment of today's magneto-optics, progress also relies on an ever-increasing theoretical understanding of MO effects from a quantum mechanical perspective (see section 2), as well as using electromagnetic theory and modelling approaches (see section 3) to enable quantitatively reliable predictions for ever more complex materials, metamaterials, and device geometries. The latest advances in established MO methodologies and especially the utilization of the MO Kerr effect (MOKE) are presented in sections 4 (MOKE spectroscopy), 5 (higher order MOKE effects), 6 (MOKE microscopy), 8 (high sensitivity MOKE), 9 (generalized MO ellipsometry), and 20 (Cotton–Mouton effect in two-dimensional materials). In addition, MO effects are now being investigated and utilized in spectral ranges, to which they originally seemed completely foreign, as those of synchrotron radiation x-rays (see section 14, Despite our best attempt to represent the field of magneto-optics accurately and do justice to all its novel developments and its diversity, the research area is so extensive and active that there remains great latitude in deciding what to include in an article of this sort, which in turn means that some areas might not be adequately represented here. However, we feel that the 20 sections that form this 2022 magneto-optics roadmap article, each written by experts in the field and addressing a specific subject on only two pages, provide an accurate snapshot of where this research field stands today. Correspondingly, it should act as a valuable reference point and guideline for emerging research directions in modern magneto-optics, as well as illustrate the directions this research field might take in the foreseeable future.