Seasonal Variation of Eutrophication in Some Lakes of Danube Delta Biosphere Reserve

Liliana, TÖRÖK; Tőrök, Zsolt Győző; Cârstea, Elfrida M.; Săvăstru, D.

doi:10.2175/106143016x14733681696248

Cited by 7 publications

(4 citation statements)

References 25 publications

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“…The N-P ratio varied between 4.7 and 451 [46]. A spectral analysis of specific phytoplankton pigments was applied by Torok et al in 2017 as a diagnostic marker to establish the distribution and composition of phytoplankton taxonomic groups [47]. Sampling campaigns were performed throughout 2014, and nine sampling points were established.…”

Section: Resultsmentioning

confidence: 99%

“…The ratios of the release rate of inorganic nitrogen by tubificids to sedimentation rate of organic nitrogen were 8.26 and 6.39%. y n n [47] Danube Delta 1 Spectral analysis of specific phytoplankton pigments was applied as a diagnostic marker to establish the distribution and composition of phytoplankton taxonomic groups. Fluorescence spectroscopy was used to quantify changes in dissolved organic matter (DOM).…”

Section: Measurements ** Namementioning

confidence: 99%

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Overview of the Eutrophication in Romanian Lakes and Reservoirs

Dumitran,

Vuta,

Popa

2024

Limnological Review

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In this paper, attention is drawn to the deterioration of Romanian surface water ecosystems due to eutrophication, an important environmental issue both at national and international levels. An inventory of existing studies dealing with the issue of the eutrophication of lakes and reservoirs in Romania is made, aiming to identify the main problems Romania is facing in monitoring, classifying, and managing eutrophic ecosystems. On Web of Science, the keyword “Eutrophication”, with “Romania” as country/region, leads to 50 publications, which are analyzed in this review. The number of articles found does not reflect the real environmental issue represented by eutrophic lakes and reservoirs in Romania. At a national level, only 126 lakes and reservoirs have been monitored and assessed between 2018 and 2020, in terms of ecological status/ecological potential. Thus, at a global evaluation, 77% of natural lakes and 33% of artificial ones do not reach the quality objectives. The results of this study showed that the frequency of measurements taken by water quality indicators is not the strongest point of measurement campaigns, as it is not sufficient for the diagnosis of eutrophic lakes, and supplementary measures must be undertaken to better understand and mitigate this phenomenon.

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Section: Resultsmentioning

confidence: 99%

Section: Measurements ** Namementioning

confidence: 99%

Overview of the Eutrophication in Romanian Lakes and Reservoirs

Dumitran,

Vuta,

Popa

2024

Limnological Review

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“…Danube Delta ecosystems are very dynamic, including both fresh and brackish waters, and they are vulnerable to numerous natural and anthropogenic pressures that may considerably change their natural dynamics and have negative consequences on their structure and function [10]. The natural and anthropogenic stressors behave differently on a spatial and temporal scale, determining an oxygen deficiency, nutrient enrichment and eventually, eutrophication [11,12]. Generally, the quality of the transitional waters from the Danube Delta macro-ecosystem depends on the local and regional drivers, i.e., the interaction of the River Danube with the Black Sea, geomorphological characteristics of the aquatic basins, landscape, geological substrate, and climate changes (droughts, floods, variations of river water level, increase in air temperature etc.)…”

Section: Introductionmentioning

confidence: 99%

Sezonowa i przestrzenna zmienność jakości wody w systemie jezior Lumina-Rosu w delcie Dunaju w Rumunii

Catianis,

Constantinescu,

Grosu

et al. 2024

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The main aim of the present scientific paper is to assess water quality of the surface water of various lakes located in the Lumina-Rosu interdistributary depression, Danube Delta, Romania. As specific objectives, the paper considered to spot the main potential sources of contamination and their environmental impacts on aquatic ecosystems. Equally, the purpose of the article is to emphasize the importance of monitoring the water quality of the Danube Delta, for preserving these unique natural water resources and their ecosystem services (fresh water, biodiversity, flood control, recreation, nutrient cycling, fishing and other traditional activities, ecotourism). Surface water samples collected from several control sections situated on the main tributaries and canals, as well as from lakes were investigated physically (To - C, EC - μS/cm, TDS - mg/L, turbidity - NTU units, TSS - mg/L) and chemically (pH - units, DO - mg/L, N-NO2- - mg/L, N-NO3- - mg/L, P-PO43-- mg/L, Chla - mg/L, SiO2 - mg/L, TOC - mg/L, SO42- - mg/L, S2- - mg/L, H2S - mg/L and synthetic detergents - mg/L). Generally, the hydro-physical-chemical characteristics and water quality assessment of the surface waters of the lakes manifest the combined effect of both processes occurred in the catchment (weathering, sediment supply and transport), as well as the in situ lake processes (photosynthesis, sediment mixing, biogeochemical cycling, evaporation, eutrophication, productivity changes). Overall, the physical and chemical characteristics of the sampling sites investigated at high waters of the Danube are quite similar to those measured at low waters. The differences that mainly occurred within the lakes are more related to the limnological variables and the local environmental conditions. Anyway, a significant seasonal variation was noticed in the lakes, during the dry period, when different physical and chemical characteristics appeared to be influenced by high air temperature, lack of precipitation, low water level regime, low dissolved oxygen level regime, all related to climate change effects etc. Moreover, the anthropogenic factor that left its mark on some physical-chemical characteristics of water should not be omitted either. However, the results obtained within this study did not show such alarming values as might have dangerous effects on the investigated aquatic environments. The water quality information within this case study may be used for improving the understanding of the water quality issues and to better coordinate and plan for future monitoring activities in and around the Danube Delta environment. The results will contribute to updating the existing database with relevant information for a sustainable future of the Danube Delta and in similar areas that are subjected to such environmental challenges.

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“…Due to the increasing scarcity of water, existing aquatic environments must be monitored in order to ensure safe water for supply and to predict processes that impact these environments and may endanger their ecological integrity. Therefore, phytoplankton has been requested as a good monitoring tool, since the community has the ability to respond to changes in the environmental gradient due to the short life cycle and diverse adaptive strategies [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Ecological indexes and phytoplankton structure of urban reservoirs supplied by estuarine waters and under the effects of seasonality (Belém, Pará, Brazil)

Brito Pires,

Garcia Díaz,

Brabo de Sousa

et al. 2023

Sci. Plena

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Ecological indices are used in the study of phytoplankton because they are related to their productivity and can describe the stresses caused by anthropogenic impacts on the aquatic environment. The aim of this study was to evaluate the phytoplankton structure and the application of ecological indices in the monitoring of water quality in public supply reservoirs in Belém (Pará). Monthly sampling occurred in four stations in the Bologna and Água Preta reservoirs from January to October/2019, to determine the abiotic and biotic factors and the calculation of ecological indices. Turbidity, transparency, precipitation and dissolved oxygen were the main abiotic variables that differentiated the reservoirs, evidencing the estuarine, seasonal and anthropogenic influence on species distribution. A total of 187 phytoplankton species were identified with representation of diatoms. In January, Água Preta reservoir presented lower diversity (2.14 ± 0.58 nats.ind-1), equitability (0.57 ± 0.14) and higher dominance (0.25 ± 0.19) with the species Trachelomonas volvocina in higher density, contrary to June that presented higher diversity and equitability and no species dominance. The Bolonha reservoir showed lower richness (8.3 ± 1.9), diversity (1.2 ± 0.5 nats.ind-1) and equitability (0.32 ± 0.12) with dominance of the species Gonyostomum sp. (0.55 ± 0.19). In this sense, the Água Preta reservoir was considered diverse with species well distributed in the environment, while the Bolonha reservoir showed low diversity and dominance of a phytoplankton species. Ecological indices describe well the spatio-temporal variation of phytoplankton in these reservoirs and are a good approach in monitoring environmental quality.

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Seasonal Variation of Eutrophication in Some Lakes of Danube Delta Biosphere Reserve

Cited by 7 publications

References 25 publications

Overview of the Eutrophication in Romanian Lakes and Reservoirs

Overview of the Eutrophication in Romanian Lakes and Reservoirs

Sezonowa i przestrzenna zmienność jakości wody w systemie jezior Lumina-Rosu w delcie Dunaju w Rumunii

Ecological indexes and phytoplankton structure of urban reservoirs supplied by estuarine waters and under the effects of seasonality (Belém, Pará, Brazil)

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