This page has only limited features, please log in for full access.

Dr. Nikolaos Skoulikidis
Hellenic Centre for Marine Research - Inst. of Marine Biological Resources & Inland Waters, Dept. of Inland Waters, 19013 Anavissos Attikis, Greece

Basic Info


Research Keywords & Expertise

0 Water Quality
0 Ecological status
0 River Basin Management
0 Temporary (intermittent) streams
0 Biogeochemical process

Fingerprints

Ecological status
River Basin Management

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 03 July 2021 in Water
Reads 0
Downloads 0

Based on historical and WFD-compliant data, the recent inter-annual ecological status and the long-term chemical-physicochemical quality trends of eighteen characteristic Greek rivers have been assessed and interpreted in view of implementing EU environmental policies and the evolution of human pressures. Considering predominating poor ecological status in most of the river outflows, the strengths and weaknesses of the WFD implementation have been highlighted. The long-term decrease of ammonium and nitrite concentrations along with relatively low recent BOD5 levels, indicate a general improvement of WWTP infrastructure in Greece and the other riparian countries, whereas the improvement of nitrate quality is attributed to the reduction of fertilizers use, and possibly, to the successful application of the Nitrates Directive in certain basins. Despite capacity building in governance and administrative infrastructure the recent years, River Basin Management Plans (RBMPs) are being implemented centrally, largely mechanistically, with minor public participation. Regarding WFD implementation weaknesses and gaps, concrete proposals have been formulated considering both policy/administrative and technical issues. To efficiently conserve and restore aquatic ecosystems, the forthcoming RBMPs should be consistent with ecosystem services principles focusing on nature-based solutions, along with changing attitudes of the state authorities and the public.

ACS Style

Nikolaos Skoulikidis; Ioannis Karaouzas; Yorgos Amaxidis; Maria Lazaridou. Impact of EU Environmental Policy Implementation on the Quality and Status of Greek Rivers. Water 2021, 13, 1858 .

AMA Style

Nikolaos Skoulikidis, Ioannis Karaouzas, Yorgos Amaxidis, Maria Lazaridou. Impact of EU Environmental Policy Implementation on the Quality and Status of Greek Rivers. Water. 2021; 13 (13):1858.

Chicago/Turabian Style

Nikolaos Skoulikidis; Ioannis Karaouzas; Yorgos Amaxidis; Maria Lazaridou. 2021. "Impact of EU Environmental Policy Implementation on the Quality and Status of Greek Rivers." Water 13, no. 13: 1858.

Chapter
Published: 28 February 2021 in The Handbook of Environmental Chemistry
Reads 0
Downloads 0

Largely using monitored data, we estimated water and nutrient fluxes to the Aegean Sea for two time periods, a past period (from 1980 to 1994 regarding discharge and 1980–1994 or broadly 1995–2000 regarding nutrients) and a recent period (between 2012 and 2015 for both, discharge and nutrients). The total water fluxes entering the Aegean were estimated to 481.4 km3/year, of which 62.3% were derived from the Black Sea via the Dardanelles straits, 26.8% by direct precipitation, 10.4% by the Balkan and Asian Minor rivers, and 2.2% by submarine springs. Regarding nutrients, considering only the Balkan rivers (in lack of data from Turkish rivers), the total fluxes of DIN (dissolved inorganic nitrogen) were 268.5 and of P-PO4 7.17 kt/year. The main DIN sources were the Black Sea inputs (48.4%) and precipitation (38.4%), whereas for phosphorus the rivers were the main contributors (46%). Considering this result, combined with the anticipated dramatic increase of hydropower production, there are concerns of enhanced future P limitation regarding marine photosynthesis as a result of more efficient phosphorus retention in reservoirs. Since silica is also massively retained within reservoirs, changes in riverine Si:N:P stoichiometry are expected to affect phytoplankton composition. Natural sediment fluxes were estimated to 61.8 Mt/year; however, sediment flux assessment includes large uncertainties. Retention of excessive sediment amounts within reservoirs, combined with a sea level rise, is expected to induce significant land losses in coastal areas. Finally, the Aegean Sea is still under threat regarding organic pollution, while there is a need for toxic pollutants monitoring and control in the circum-Aegean area to safeguard this spectacular environment for future generations.

ACS Style

Nikolaos Th. Skoulikidis; Angeliki Mentzafou. Freshwater and Matter Inputs in the Aegean Coastal System. The Handbook of Environmental Chemistry 2021, 1 -42.

AMA Style

Nikolaos Th. Skoulikidis, Angeliki Mentzafou. Freshwater and Matter Inputs in the Aegean Coastal System. The Handbook of Environmental Chemistry. 2021; ():1-42.

Chicago/Turabian Style

Nikolaos Th. Skoulikidis; Angeliki Mentzafou. 2021. "Freshwater and Matter Inputs in the Aegean Coastal System." The Handbook of Environmental Chemistry , no. : 1-42.

Journal article
Published: 03 March 2020 in Sustainability
Reads 0
Downloads 0

This is a case study on a small mountainous island in the Aegean Sea with the policy goal of preparing it to become member of UNESCO’s World Network of Biosphere Reserves. While the local community opted for such an identity very early on, there are a number of obstacles to be overcome. The multidisciplinary research is based upon a sociometabolic approach and focuses on two issues: The transformation of agriculture, mainly herding of sheep and goats, and the shift to tourism. The degradation of the landscape caused by extensive roaming of goats and sheep constitute one of the major sustainability challenges of the island. We analyze farmers’ opportunities and describe new initiatives to get out of this deadlock. The impacts of the transition to tourism are addressed from an infrastructural perspective: A shift from traditional stone buildings to bricks and concrete, the establishment of new roads and ports, and the challenges to water supply and wastewater removal, also with reference to the quality and amounts of wastes generated that need to be dealt with. The island has so far escaped mass tourism and attracts mainly eco-tourists who value its remoteness and wilderness. We discuss how to serve this clientele best in the future, and increase local job opportunities and income while maintaining environmental quality. Finally, we reflect upon emerging new forms of local collaboration and the impact of our research efforts on a sustainability transition that might be on its way.

ACS Style

Marina Fischer-Kowalski; Markus Löw; Dominik Noll; Panos Petridis; Nikolaos Skoulikidis. Samothraki in Transition: A Report on a Real-World Lab to Promote the Sustainability of a Greek Island. Sustainability 2020, 12, 1932 .

AMA Style

Marina Fischer-Kowalski, Markus Löw, Dominik Noll, Panos Petridis, Nikolaos Skoulikidis. Samothraki in Transition: A Report on a Real-World Lab to Promote the Sustainability of a Greek Island. Sustainability. 2020; 12 (5):1932.

Chicago/Turabian Style

Marina Fischer-Kowalski; Markus Löw; Dominik Noll; Panos Petridis; Nikolaos Skoulikidis. 2020. "Samothraki in Transition: A Report on a Real-World Lab to Promote the Sustainability of a Greek Island." Sustainability 12, no. 5: 1932.

Journal article
Published: 10 February 2020 in Water
Reads 0
Downloads 0

Due to its rough, mountainous relief, Samothraki remains one of the last minimally disturbed islands in the Mediterranean. This paper examines the hydrogeochemical regime of the island’s surface waters as it results from geological, morphological, and hydro(geo)logical controls within a frame of minimally disturbed environmental conditions. Shallow, fractured groundwater aquifers, in combination with steep slopes and predominant weathering resistant rocks, bring about flashy stream regimes with remarkably low solute concentrations. Streams and springs revealed hydrochemical similarities. Contrary to streams chiefly draining sedimentary rocks, streams underlined by granite and ophiolite rocks do not respond hydrochemically to geochemical differences. Using ion proportions instead of concentrations, geochemical fingertips of magmatic stream basins were detected. Atmospheric inputs largely affect stream and spring composition, e.g., by 75% regarding sodium. Only 20% of dissolved oxygen and pH variance was assigned to biological activity, while nutrient levels were consistent with the undisturbed conditions of the island, except nitrate. Small mountainous springs and brooks fed by restricted, fractured groundwater aquifers with perennial flow, despite scarce summer rainfalls, may be fueled by cloud and fog condensation. High night-day stream flow differences, high atmospheric humidity predominately occurring during the night, and low stream water travel times point out toward this phenomenon.

ACS Style

Nikolaos T. Skoulikidis; Anastasia Lampou; Sofia Laschou. Unraveling Aquatic Quality Controls of a Nearly Undisturbed Mediterranean Island (Samothraki, Greece). Water 2020, 12, 473 .

AMA Style

Nikolaos T. Skoulikidis, Anastasia Lampou, Sofia Laschou. Unraveling Aquatic Quality Controls of a Nearly Undisturbed Mediterranean Island (Samothraki, Greece). Water. 2020; 12 (2):473.

Chicago/Turabian Style

Nikolaos T. Skoulikidis; Anastasia Lampou; Sofia Laschou. 2020. "Unraveling Aquatic Quality Controls of a Nearly Undisturbed Mediterranean Island (Samothraki, Greece)." Water 12, no. 2: 473.

Journal article
Published: 18 July 2019 in Water
Reads 0
Downloads 0

Grazing management practices can be erosion abatement actions for lowering soil loss and the subsequent sediment pollution of surface water bodies. Process-based Geographic Information Systems models provide the opportunity to identify critical areas and hence better target such actions across the landscape. This study implemented the SWAT (Soil Water Assessment Tool) hydrologic and catchment management model to estimate the soil loss vulnerability of the nearly pristine but highly erodible Greek island of Samothraki in the North Aegean Sea, with a typical Mediterranean climate and steep topography. Model parameterization and evaluation were carried out by taking advantage of previous modeling experience on areas with data limitations. Inter-annual and intra-annual soil loss variability and the most critical areas (subbasins) of soil loss to waters were adequately identified and grazing management scenarios, including livestock reductions by 50% and 100%, grazing period reduction, and a combination of them, were formulated and applied to investigate the degree to which soil loss could be reduced. The annual reduction results varied between scenarios in the range of 10% to 25% for the entire island, and in wider ranges for its individual subbasins, showing a high potential for reducing the vulnerability of the most pressured ones. However, due to the high importance of the natural factors of rainfall and land slopes, the erosion vulnerability of the island overall could be significantly altered only if grazing management was integrated within a vegetation regeneration plan that included reforestation.

ACS Style

Yiannis Panagopoulos; Elias Dimitriou; Nikolaos Skoulikidis. Vulnerability of a Northeast Mediterranean Island to Soil Loss. Can Grazing Management Mitigate Erosion? Water 2019, 11, 1491 .

AMA Style

Yiannis Panagopoulos, Elias Dimitriou, Nikolaos Skoulikidis. Vulnerability of a Northeast Mediterranean Island to Soil Loss. Can Grazing Management Mitigate Erosion? Water. 2019; 11 (7):1491.

Chicago/Turabian Style

Yiannis Panagopoulos; Elias Dimitriou; Nikolaos Skoulikidis. 2019. "Vulnerability of a Northeast Mediterranean Island to Soil Loss. Can Grazing Management Mitigate Erosion?" Water 11, no. 7: 1491.

Research article
Published: 14 December 2018 in Aquatic Sciences
Reads 0
Downloads 0

Environmental flow assessments (EFAs) are widely researched and applied worldwide. However, model-based frameworks integrating the flow requirements of multiple ecosystem components have been primarily developed for perennial watercourses, being inherently inapplicable in intermittent rivers (IR), which are common worldwide and may dominate arid, semi-arid and mediterranean-climate regions. In this study, we conceptualized and pilot-applied a model-based EFA in a naturally intermittent Mediterranean river reach (Evrotas, southern Greece), guided by two fundamental principles: (1) environmental flows in IR should be delivered during specific aquatic states (AS) and (2) baseflows should be provided during prolonged dry periods to prevent artificial deviation from the natural AS-sequence. The habitat preferences of benthic macroinvertebrates and of three endemic fish species were evaluated, and a two-dimensional hydrodynamic-habitat model was applied to simulate habitat suitability at various discharges. We modelled the baseflow required to maintain disconnected water pools during dry periods and the optimal baseflow required to ensure the presence of suitable habitats after flow resumption. The results show that baseflows at the 25th percentile of the abundant-riffles state can provide adequate habitat for the IR-specific communities. During prolonged dry periods, surface–groundwater interactions should be also considered for robust predictions. We highlight the use of hydrodynamic-habitat models in IR-based EFAs as a key-tool to estimate the AS timing and duration and, consequently, the timing-duration of the respective environmental flow components. Future studies should, inter alia, (1) include the aquatic-riparian vegetation to provide information on high flows-floods, and (2) incorporate groundwater models to account for surface–groundwater interactions towards a widely accepted IR-specific EFA framework.

ACS Style

Christos Theodoropoulos; Christina Papadaki; Leonidas Vardakas; Elias Dimitriou; Eleni Kalogianni; Nikolaos Skoulikidis. Conceptualization and pilot application of a model-based environmental flow assessment adapted for intermittent rivers. Aquatic Sciences 2018, 81, 10 .

AMA Style

Christos Theodoropoulos, Christina Papadaki, Leonidas Vardakas, Elias Dimitriou, Eleni Kalogianni, Nikolaos Skoulikidis. Conceptualization and pilot application of a model-based environmental flow assessment adapted for intermittent rivers. Aquatic Sciences. 2018; 81 (1):10.

Chicago/Turabian Style

Christos Theodoropoulos; Christina Papadaki; Leonidas Vardakas; Elias Dimitriou; Eleni Kalogianni; Nikolaos Skoulikidis. 2018. "Conceptualization and pilot application of a model-based environmental flow assessment adapted for intermittent rivers." Aquatic Sciences 81, no. 1: 10.

Journal article
Published: 24 October 2018 in Water
Reads 0
Downloads 0

Generic habitat suitability criteria (HC) are often developed from spatially and temporally variable hydroecological datasets to increase generality, cost-effectiveness, and time-efficiency of habitat models. For benthic macroinvertebrates (BMIs), however, there is no prior knowledge on the spatiotemporal variation in their habitat preferences and how this may be reflected in the final environmental flow (e-flow) predictions. In this study, we used a large, spatiotemporally variable BMI-hydroecological dataset and developed generic, local, and season-specific subsets of HC for three seasons and two river types within various data pre-treatment options. Each subset was used to train a fuzzy habitat model, predict the habitat suitability in two hydrodynamically-simulated river reaches, and develop/compare model-based e-flow scenarios. We found that BMIs shift their habitat preferences among seasons and river types; consequently, spatiotemporally variable e-flow predictions were developed, with the seasonal variation being greater than the typological one. Within this variation, however, we found that with proper data pre-treatment, the minimum-acceptable e-flows from the generic models mostly (65–90%) lay within the acceptable e-flows predicted by the local and season-specific models. We conclude that, within specific limitations, generic BMI-HC can be used for geographically extended, cost-effective e-flow assessments, compensating for the within-limits loss of predictive accuracy.

ACS Style

Christos Theodoropoulos; Nikolaos Skoulikidis; Anastasios Stamou; Elias Dimitriou. Spatiotemporal Variation in Benthic-Invertebrates-Based Physical Habitat Modelling: Can We Use Generic Instead of Local and Season-Specific Habitat Suitability Criteria? Water 2018, 10, 1508 .

AMA Style

Christos Theodoropoulos, Nikolaos Skoulikidis, Anastasios Stamou, Elias Dimitriou. Spatiotemporal Variation in Benthic-Invertebrates-Based Physical Habitat Modelling: Can We Use Generic Instead of Local and Season-Specific Habitat Suitability Criteria? Water. 2018; 10 (11):1508.

Chicago/Turabian Style

Christos Theodoropoulos; Nikolaos Skoulikidis; Anastasios Stamou; Elias Dimitriou. 2018. "Spatiotemporal Variation in Benthic-Invertebrates-Based Physical Habitat Modelling: Can We Use Generic Instead of Local and Season-Specific Habitat Suitability Criteria?" Water 10, no. 11: 1508.

Research article
Published: 23 August 2018 in Ecohydrology
Reads 0
Downloads 0

In their effort to balance anthropogenic water demand and ecosystem conservation within a sustainable water resources management framework, water managers and stakeholders need sound scientific guidance. In this study, we applied a two‐dimensional hydrodynamic habitat model using benthic macroinvertebrates as the target aquatic community, and carried out an environmental flow (eflow) assessment downstream of the Marathon Reservoir (Attica, central Greece). Hydrology‐based eflow scenarios were additionally developed over an 11‐year period, and the lowest acceptable ecosystem‐based eflow was compared with the hydrology‐based environmental flow predictions. We found that the hydrological methods tend to under‐estimate the eflows required to ensure functional aquatic ecosystems. The results showed that (i) the different hydrological methods developed highly variable eflow scenarios, ranging from 0.0006 m3/s to 0.18 m3/s, (ii) the ecosystem‐based environmental flow was up to 183% higher than the hydrology‐based ones and 26% to 465% higher than those defined by the national legislation and (iii) the probability of agreement between hydrological and ecological predictions was 12.5%, as only one out of the eight hydrology‐based scenarios coincided with the ecosystem‐based eflows. We conclude that hydrological methods should be used with caution in the absence of ecological information. Their use as stand‐alone tools seems problematic and bears a high risk of producing inappropriate environmental flow scenarios. Integrative frameworks combining hydrological‐ecological methods could be useful to provide information on what is ecologically‐acceptable and hydrologically‐socially feasible, but since the two methods comprise structurally‐different, non‐interacting concepts, they are inherently insufficient to increase the confidence of predicting and selecting environmental flows.

ACS Style

Christos Theodoropoulos; Spyridon Georgalas; Nikolaos Mamassis; Anastasios Stamou; Peter Rutschmann; Nikolaos Skoulikidis. Comparing environmental flow scenarios from hydrological methods, legislation guidelines, and hydrodynamic habitat models downstream of the Marathon Dam (Attica, Greece). Ecohydrology 2018, 11, e2019 .

AMA Style

Christos Theodoropoulos, Spyridon Georgalas, Nikolaos Mamassis, Anastasios Stamou, Peter Rutschmann, Nikolaos Skoulikidis. Comparing environmental flow scenarios from hydrological methods, legislation guidelines, and hydrodynamic habitat models downstream of the Marathon Dam (Attica, Greece). Ecohydrology. 2018; 11 (8):e2019.

Chicago/Turabian Style

Christos Theodoropoulos; Spyridon Georgalas; Nikolaos Mamassis; Anastasios Stamou; Peter Rutschmann; Nikolaos Skoulikidis. 2018. "Comparing environmental flow scenarios from hydrological methods, legislation guidelines, and hydrodynamic habitat models downstream of the Marathon Dam (Attica, Greece)." Ecohydrology 11, no. 8: e2019.

Journal article
Published: 01 March 2018 in Science of The Total Environment
Reads 0
Downloads 0

Temporary rivers are dynamic and complex ecosystems that are widespread in arid and semi-arid regions, such as the Mediterranean. Biotic communities adapted in their intermittent nature could withstand recurrent drought events. However, anthropogenic disturbances in the form of water stress and chemical pollution challenge biota with unpredictable outcomes, especially in view of climate change. In this study we assess the response of the biotic community of a temporary river to environmental stressors, focusing on water stress and pollution. Towards this aim, several metrics of four biotic groups (diatoms, macrophytes, macroinvertebrates and fish) were applied. All biotic groups responded to a pollution gradient mainly driven by land use, distinct functional groups of all biota responded to water stress (a response related to the rheophilic nature of the species and their resistance to shear stress), while the combined effects of water stress and pollution were apparent in fish. Biotic groups presented a differential temporal response to water stress, where diatom temporal assemblage patterns were explained by water stress variables of short-time response (15days), while the responses of the other biota were associated to longer time periods. There were two time periods of fish response, a short (15days) and a long-time response (60-75days). When considering management decisions, our results indicate that, given the known response of river biota to pollution, biomonitoring of temporary rivers should also involve metrics that can be utilized as early warnings of water stress.

ACS Style

Ioannis Karaouzas; Evangelia Smeti; Aikaterini Vourka; Leonidas Vardakas; Aggeliki Mentzafou; Elisabet Tornés; Sergi Sabater; Isabel Muñoz; Nikolaos Th. Skoulikidis; Eleni Kalogianni. Assessing the ecological effects of water stress and pollution in a temporary river - Implications for water management. Science of The Total Environment 2018, 618, 1591 -1604.

AMA Style

Ioannis Karaouzas, Evangelia Smeti, Aikaterini Vourka, Leonidas Vardakas, Aggeliki Mentzafou, Elisabet Tornés, Sergi Sabater, Isabel Muñoz, Nikolaos Th. Skoulikidis, Eleni Kalogianni. Assessing the ecological effects of water stress and pollution in a temporary river - Implications for water management. Science of The Total Environment. 2018; 618 ():1591-1604.

Chicago/Turabian Style

Ioannis Karaouzas; Evangelia Smeti; Aikaterini Vourka; Leonidas Vardakas; Aggeliki Mentzafou; Elisabet Tornés; Sergi Sabater; Isabel Muñoz; Nikolaos Th. Skoulikidis; Eleni Kalogianni. 2018. "Assessing the ecological effects of water stress and pollution in a temporary river - Implications for water management." Science of The Total Environment 618, no. : 1591-1604.

Original articles
Published: 02 January 2018 in Journal of Ecohydraulics
Reads 0
Downloads 0

Although various methods are currently available for modelling the habitat preferences of aquatic biota, studies comparing the performance of data-driven habitat models are limited. In this study, we assembled a benthic-macroinvertebrate microhabitat-preference dataset and used it to evaluate the predictive accuracy of regression-based univariate Habitat Suitability Curves (HSC), Boosted Regression Trees (BRT), Random Forests (RF), fuzzy-logic-based models using the weighted average (FLWA), maximum membership (FLMM), mean of maximum (FLM) and centroid (FLC) defuzzification algorithms and fuzzy rule-based Bayesian inference (FRB). The results show that the BRT model was the most accurate, closely followed by RF, FRB, FLM and FLMM while the FLC and FLWA algorithms had the lowest performance. However, due to the imbalanced nature of the dataset and in contrast to the fuzzy rule-based algorithms, the HSC, BRT and RF models failed to accurately predict the habitat suitability in low-scored microhabitats. We conclude that, given balanced datasets, BRT and RF can be effectively used in habitat suitability modelling. For imbalanced datasets, a properly adjusted RF model can be applied but when the input dataset is large enough to provide sufficient data-driven IF–THEN rules to train an FRB, FLMM or FLM algorithm, these models will produce the most accurate predictions.

ACS Style

Christos Theodoropoulos; Aikaterini Vourka; Nikolaos Skoulikidis; Peter Rutschmann; Anastasios Stamou. Evaluating the performance of habitat models for predicting the environmental flow requirements of benthic macroinvertebrates. Journal of Ecohydraulics 2018, 3, 30 -44.

AMA Style

Christos Theodoropoulos, Aikaterini Vourka, Nikolaos Skoulikidis, Peter Rutschmann, Anastasios Stamou. Evaluating the performance of habitat models for predicting the environmental flow requirements of benthic macroinvertebrates. Journal of Ecohydraulics. 2018; 3 (1):30-44.

Chicago/Turabian Style

Christos Theodoropoulos; Aikaterini Vourka; Nikolaos Skoulikidis; Peter Rutschmann; Anastasios Stamou. 2018. "Evaluating the performance of habitat models for predicting the environmental flow requirements of benthic macroinvertebrates." Journal of Ecohydraulics 3, no. 1: 30-44.

Journal article
Published: 01 December 2017 in Science of The Total Environment
Reads 0
Downloads 0

Water stress is a key stressor in Mediterranean intermittent rivers exacerbating the negative effects of other stressors, such as pollutants, with multiple effects on different river biota. The current study aimed to determine the response of macroinvertebrate and fish assemblages to instream habitat and water chemistry, at the microhabitat scale and at different levels of water stress and pollution, in an intermittent Mediterranean river. Sampling was conducted at high and low summer discharge, at two consecutive years, and included four reaches that were targeted for their different levels of water stress and pollution. Overall, the macroinvertebrate fauna of Evrotas River indicated high resilience to intermittency, however, variation in community structure and composition occurred under acute water stress, due to habitat alteration and change in water physico-chemistry, i.e. water temperature increase. The combined effects of pollution and high water stress had, however, pronounced effects on species richness, abundance and community structure in the pollution impacted reach, where pollution sensitive taxa were almost extirpated. Fish response to drought, in reaches free of pollution, consisted of an increase in the abundance of the two small limnophilic species, coupled with their shift to faster flowing riffle habitats, and a reduction in the abundance of the larger, rheophilic species. In the pollution impacted reach, however, the combination of pollution and high water stress led to hypoxic conditions assumed to be the leading cause of the almost complete elimination of the fish assemblage. In contrast, the perennial Evrotas reaches with relatively stable physicochemical conditions, though affected hydrologically by drought, appear to function as refugia for fish during high water stress. When comparing the response of the two biotic groups to combined acute water stress and pollution, it is evident that macroinvertebrates were negatively impacted, but fish were virtually eliminated under the two combined stressors.

ACS Style

Eleni Kalogianni; Aikaterini Vourka; Ioannis Karaouzas; Leonidas Vardakas; Sofia Laschou; Nikolaos Th. Skoulikidis. Combined effects of water stress and pollution on macroinvertebrate and fish assemblages in a Mediterranean intermittent river. Science of The Total Environment 2017, 603-604, 639 -650.

AMA Style

Eleni Kalogianni, Aikaterini Vourka, Ioannis Karaouzas, Leonidas Vardakas, Sofia Laschou, Nikolaos Th. Skoulikidis. Combined effects of water stress and pollution on macroinvertebrate and fish assemblages in a Mediterranean intermittent river. Science of The Total Environment. 2017; 603-604 ():639-650.

Chicago/Turabian Style

Eleni Kalogianni; Aikaterini Vourka; Ioannis Karaouzas; Leonidas Vardakas; Sofia Laschou; Nikolaos Th. Skoulikidis. 2017. "Combined effects of water stress and pollution on macroinvertebrate and fish assemblages in a Mediterranean intermittent river." Science of The Total Environment 603-604, no. : 639-650.

Chapter
Published: 30 March 2017 in The Handbook of Environmental Chemistry
Reads 0
Downloads 0

This chapter is the outcome of a 10-year ecological monitoring survey in the Evrotas River Basin (ERB). Synthesising the main outcomes of past and ongoing research projects, it presents an overview of the basin’s geographical, geological, hydrological and ecological features, focused on the ecological status according to the Water Framework Directive 2000/60/EC, and assesses the degree of environmental degradation caused by the major pollution sources and other anthropogenic pressures. Chemical, hydromorphological and biological data from studies carried out in the ERB during the past decade are integrated to derive spatial and temporal trends in environmental degradation. Despite the numerous sources of organic and inorganic pollution, which include, inter alia, olive mill and fruit juice processing wastewaters and agricultural, industrial and urban runoffs, the overall ecological degradation of the ERB is assessed as moderate and is located mainly at the downstream half of the basin, where the anthropogenic activities become intensified. However, the major impact in the ERB during the last decades has been the over-exploitation of the surface and groundwater resources for irrigation, which has resulted in the artificial desiccation of large parts of the basin’s hydrological network. Despite the aforementioned issues, the aquatic benthic biota of the basin shows high resilience, but the fish fauna is severely affected by hydrological and morphological alteration. Biomonitoring, conservation and management responses to drought and pollution require approaches, which account for spatial and temporal variability. Within this perspective, a programme of measures is proposed, aiming at preserving and restoring the basin’s water resources and aquatic ecosystem.

ACS Style

Ioannis Karaouzas; Christos Theodoropoulos; Leonidas Vardakas; Stamatis Zogaris; Nikolaos Skoulikidis. The Evrotas River Basin: 10 Years of Ecological Monitoring. The Handbook of Environmental Chemistry 2017, 59, 279 -326.

AMA Style

Ioannis Karaouzas, Christos Theodoropoulos, Leonidas Vardakas, Stamatis Zogaris, Nikolaos Skoulikidis. The Evrotas River Basin: 10 Years of Ecological Monitoring. The Handbook of Environmental Chemistry. 2017; 59 ():279-326.

Chicago/Turabian Style

Ioannis Karaouzas; Christos Theodoropoulos; Leonidas Vardakas; Stamatis Zogaris; Nikolaos Skoulikidis. 2017. "The Evrotas River Basin: 10 Years of Ecological Monitoring." The Handbook of Environmental Chemistry 59, no. : 279-326.

Journal article
Published: 01 February 2017 in Ecological Indicators
Reads 0
Downloads 0
ACS Style

Christos Theodoropoulos; Aikaterini Vourka; Anastasios Stamou; Peter Rutschmann; Nikolaos Skoulikidis. Response of freshwater macroinvertebrates to rainfall-induced high flows: A hydroecological approach. Ecological Indicators 2017, 73, 432 -442.

AMA Style

Christos Theodoropoulos, Aikaterini Vourka, Anastasios Stamou, Peter Rutschmann, Nikolaos Skoulikidis. Response of freshwater macroinvertebrates to rainfall-induced high flows: A hydroecological approach. Ecological Indicators. 2017; 73 ():432-442.

Chicago/Turabian Style

Christos Theodoropoulos; Aikaterini Vourka; Anastasios Stamou; Peter Rutschmann; Nikolaos Skoulikidis. 2017. "Response of freshwater macroinvertebrates to rainfall-induced high flows: A hydroecological approach." Ecological Indicators 73, no. : 432-442.

Journal article
Published: 27 October 2016 in Journal of Open Source Software
Reads 0
Downloads 0
ACS Style

Christos Theodoropoulos; Nikolaos Skoulikidis; Anastasios Stamou. Habfuzz: A tool to calculate the instream hydraulic habitat suitability using fuzzy logic and fuzzy Bayesian inference. Journal of Open Source Software 2016, 1, 1 .

AMA Style

Christos Theodoropoulos, Nikolaos Skoulikidis, Anastasios Stamou. Habfuzz: A tool to calculate the instream hydraulic habitat suitability using fuzzy logic and fuzzy Bayesian inference. Journal of Open Source Software. 2016; 1 (6):1.

Chicago/Turabian Style

Christos Theodoropoulos; Nikolaos Skoulikidis; Anastasios Stamou. 2016. "Habfuzz: A tool to calculate the instream hydraulic habitat suitability using fuzzy logic and fuzzy Bayesian inference." Journal of Open Source Software 1, no. 6: 1.

Journal article
Published: 19 November 2015 in Water, Air, & Soil Pollution
Reads 0
Downloads 0

The directive 2008/105/EC suggests the use of sediment or biota matrix for long-term monitoring of specific priority pollutants that tend to accumulate. But, the intermittent nature of flow in the majority of the Mediterranean rivers results in large variability of biological communities and especially fish, making advantageous the examination of pollution trend in sediment matrix and not in living organisms (biota). In this study, sediment environmental quality standards (EQSs) and sediment quality indicators (SQIs) were used to assess pollution by heavy metals (cadmium, nickel, lead, mercury, arsenic, chromium, copper, and zinc) and polycyclic aromatic hydrocarbons (PAHs) in Evrotas River, South Greece, monitored seasonally for 2 years (2009–2010) in five sampling sites. The results showed that, based on SQIs (geoaccumulation index (Igeo), enrichment factor (EF), and modified degree of contamination (mCd)), sediments of the Evrotas River can be classified as “low polluted,” with some exceptions of “extreme pollution.” EQS assessment revealed heavy metal pollution ranging from “low” to “medium high.” Furthermore, based on the Hakanson’s ecological risk index (RI) method, heavy metal potential risk was classified from “low” to “extreme.” Cadmium showed the highest RI values, while mercury reached “moderate” pollution level. The average ΣPAH concentration (24.4 ng g−1) was lower than both the reported EQSs and the values found in literature for unpolluted or moderately polluted river sediments. Increased heavy metal and PAH concentrations were found in sites where mixing of freshwater with reclaimed water occurred. EQSs are suggested to be supplemented with the RI or EF index that consider the natural background to assist a first ecorisk assessment and should be foreseen by 2008/105/EC directive. Sediments can be considered as a valuable matrix in assessing the spatial and temporal trends of several contaminants and should be included in the monitoring program of temporary river management plans. Special attention should be given when defining reference sites and the sampling period. Decreasing flow period at the beginning of the spring prevailed in order to diminish any disturbance by flash flood events.

ACS Style

O. Tzoraki; I. Karaouzas; Luisa Patrolecco; N. Skoulikidis; N. P. Nikolaidis. Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metal Occurrence in Bed Sediments of a Temporary River. Water, Air, & Soil Pollution 2015, 226, 1 -19.

AMA Style

O. Tzoraki, I. Karaouzas, Luisa Patrolecco, N. Skoulikidis, N. P. Nikolaidis. Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metal Occurrence in Bed Sediments of a Temporary River. Water, Air, & Soil Pollution. 2015; 226 (12):1-19.

Chicago/Turabian Style

O. Tzoraki; I. Karaouzas; Luisa Patrolecco; N. Skoulikidis; N. P. Nikolaidis. 2015. "Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metal Occurrence in Bed Sediments of a Temporary River." Water, Air, & Soil Pollution 226, no. 12: 1-19.

Journal article
Published: 30 June 2009 in Journal of Hydrology
Reads 0
Downloads 0

Hydrological pathways, speciation, and in-stream spatio-temporal variations (including initial flood pulses), along with soil/sediment characteristics, pointed out to the most probable factors and processes driving the origin, levels and dynamics of nutrients in a minimally disturbed Greek temporal river. Nitrogen and phosphorus were predominately found in the organic form and, despite the high suspended sediment transport, in the dissolved phase. Forest soil leaching and erosion fuelled the river with organic nutrients both in the dissolved and particulate phase, especially at the upstream portion of the basin. This part of the basin exhibited “pristine” dissolved nutrient levels (e.g. 30 μg/l DIN, 1.04 μg/l P–PO4), despite substantial transport through precipitation and subsurface flow, suggesting that certain biogeochemical processes acting in the watershed and in-stream effectively reduce riverine dissolved nutrient concentrations. Intense erosion caused a significant downstream increase of suspended sediments and associated nutrient concentrations. Flushing processes, that were detected even in a monthly base in particular river stretches, enhanced dissolved and particulate nutrient concentrations. Initial flood pulses created “hot moments” chiefly for suspended sediments (RMF during initial flood events reached up to 7) and associated nutrients (e.g. RMF of POC during initial flood events reached up to 32), although flood event sediments presented lower nutrient portions compared to usual sediment transport. Flush peaks of ammonia (max 19 mg/l NH4) and nitrite (max 42 μg/l NO2), that surpassed aquatic quality standards, were attributed to rapid mineralization of organic matter upon rewetting and subsequent nitrification. River bed sediments were characterized by organic carbon and nitrogen losses, due to leaching and mineralization processes, and phosphorus retention, thus affecting nutrient ratios and hence photosynthesis in receiving waters.

ACS Style

Nikolaos Skoulikidis; Yorgos Amaxidis. Origin and dynamics of dissolved and particulate nutrients in a minimally disturbed Mediterranean river with intermittent flow. Journal of Hydrology 2009, 373, 218 -229.

AMA Style

Nikolaos Skoulikidis, Yorgos Amaxidis. Origin and dynamics of dissolved and particulate nutrients in a minimally disturbed Mediterranean river with intermittent flow. Journal of Hydrology. 2009; 373 (1-2):218-229.

Chicago/Turabian Style

Nikolaos Skoulikidis; Yorgos Amaxidis. 2009. "Origin and dynamics of dissolved and particulate nutrients in a minimally disturbed Mediterranean river with intermittent flow." Journal of Hydrology 373, no. 1-2: 218-229.

Review article
Published: 01 April 2009 in Science of The Total Environment
Reads 0
Downloads 0

Fifteen major Balkan rivers with over 80% of the inflows in Eastern Mediterranean were examined for their environmental state within the DPSIR framework. Physicogeographic and hydrochemical conditions differ substantially among river basins, which may be roughly classified into three main zones. Despite strong fragmentation, most of the rivers are liable to flash floods and have low summer flow. Decreasing precipitation and (mis)management caused a dramatic discharge reduction over the last decades. Wars, political instability, economical crises over the past decades, combined with administrative and structural constraints, poor environmental planning and inspection and, frequently, a lack of environmental awareness imposed significant pressures on rivers. Large wetland areas were drained in favour of widespread intensive agriculture. The treatment of municipal wastewaters is barely adequate in Greece and insufficient elsewhere, while management and treatment of mining and industrial wastewaters is overall poor. In general, lowland river sections are hydro-morphologically modified and are at the greatest pollution risk, while upstream areas mostly retain their natural conditions. Nutrient concentrations in a number of central and eastern Balkan rivers often exceed quality standards, whereas pesticides and heavy metals, partly of geochemical origin, occasionally exceed quality standards. Reservoirs retain vast masses of sediments, thus adversely affecting delta evolution, while dam operation disturbs the seasonal hydrological and hydrochemical regimes. Almost all Balkan countries face daunting water resource challenges because of urgently needed investments in water supply, sanitation, irrigation, and hydroelectricity. International treaties and designations and European Union Directives have mobilized pollution mitigation and conservation efforts. However, the application of environmental legislation has proved in a number of cases inadequate. Constraints arise from long-standing top-down planning traditions, inadequate planning of national environmental policies, poor administrative capacities, and heavy investment requirements, often combined with a lack of environmental awareness.

ACS Style

Nikolaos Th. Skoulikidis. The environmental state of rivers in the Balkans—A review within the DPSIR framework. Science of The Total Environment 2009, 407, 2501 -2516.

AMA Style

Nikolaos Th. Skoulikidis. The environmental state of rivers in the Balkans—A review within the DPSIR framework. Science of The Total Environment. 2009; 407 (8):2501-2516.

Chicago/Turabian Style

Nikolaos Th. Skoulikidis. 2009. "The environmental state of rivers in the Balkans—A review within the DPSIR framework." Science of The Total Environment 407, no. 8: 2501-2516.

Journal article
Published: 10 August 2008 in Hydrobiologia
Reads 0
Downloads 0

Vegoritis is a large, deep, mesotrophic, karstic lake in NW Greece, located in Ptolemais basin. Dramatic lowering of the lake’s level has occurred during the last half century due to human pressures. The Ptolemais Basin and the lake itself are subjected to serious human pressures. Pollutants are carried into the lake through both, the atmosphere and surface runoff. In order to identify the levels, and assess the origin of heavy metals in surface lake sediments, 24 samples were collected and analyzed for their grain size, as well as for their mineral, organic matter, major element and heavy metal content. The origin of heavy metals has been attributed to specific geogenic and anthropogenic sources. Despite the anthropogenic disturbance, the levels of micropollutants were low, possibly due to the low retention time of lake water and the recent increase of sedimentation rates. Only Cr, Ni, Co As, and Ba were present in relatively high concentrations. Ba is derived from the erosion of acid silicate rocks, Cr primarily from mafic rocks and secondarily from pollution, whereas for Ni and Co the opposite is true, while As is primarily attributed to fly ash deposition. The lowering of the lakes’ water level exposes sediments, which are then being oxidized. Mobilization of As and Cr could impair humans’ and ecosystems’ health.

ACS Style

Nikolaos Skoulikidis; Helen Kaberi; Dimitris Sakellariou. Patterns, origin and possible effects of sediment pollution in a Mediterranean lake. Hydrobiologia 2008, 613, 71 -83.

AMA Style

Nikolaos Skoulikidis, Helen Kaberi, Dimitris Sakellariou. Patterns, origin and possible effects of sediment pollution in a Mediterranean lake. Hydrobiologia. 2008; 613 (1):71-83.

Chicago/Turabian Style

Nikolaos Skoulikidis; Helen Kaberi; Dimitris Sakellariou. 2008. "Patterns, origin and possible effects of sediment pollution in a Mediterranean lake." Hydrobiologia 613, no. 1: 71-83.

Book chapter
Published: 01 January 2008 in Ecological Effects of Water-Level Fluctuations in Lakes
Reads 0
Downloads 0

Vegoritis is a large, deep, mesotrophic, karstic lake in NW Greece, located in Ptolemais basin. Dramatic lowering of the lake’s level has occurred during the last half century due to human pressures. The Ptolemais Basin and the lake itself are subjected to serious human pressures. Pollutants are carried into the lake through both, the atmosphere and surface runoff. In order to identify the levels, and assess the origin of heavy metals in surface lake sediments, 24 samples were collected and analyzed for their grain size, as well as for their mineral, organic matter, major element and heavy metal content. The origin of heavy metals has been attributed to specific geogenic and anthropogenic sources. Despite the anthropogenic disturbance, the levels of micropollutants were low, possibly due to the low retention time of lake water and the recent increase of sedimentation rates. Only Cr, Ni, Co As, and Ba were present in relatively high concentrations. Ba is derived from the erosion of acid silicate rocks, Cr primarily from mafic rocks and secondarily from pollution, whereas for Ni and Co the opposite is true, while As is primarily attributed to fly ash deposition. The lowering of the lakes’ water level exposes sediments, which are then being oxidized. Mobilization of As and Cr could impair humans’ and ecosystems’ health.

ACS Style

Nikolaos Skoulikidis; Helen Kaberi; Dimitrios Sakellariou. Patterns, origin and possible effects of sediment pollution in a mediterranean lake. Ecological Effects of Water-Level Fluctuations in Lakes 2008, 71 -83.

AMA Style

Nikolaos Skoulikidis, Helen Kaberi, Dimitrios Sakellariou. Patterns, origin and possible effects of sediment pollution in a mediterranean lake. Ecological Effects of Water-Level Fluctuations in Lakes. 2008; ():71-83.

Chicago/Turabian Style

Nikolaos Skoulikidis; Helen Kaberi; Dimitrios Sakellariou. 2008. "Patterns, origin and possible effects of sediment pollution in a mediterranean lake." Ecological Effects of Water-Level Fluctuations in Lakes , no. : 71-83.