scholarly journals Long-Term Changes of Species Composition and Functional Traits of Epiphytic Diatoms in the Szigetköz Region (Hungary) of the Danube River

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 776 ◽  
Author(s):  
Éva Ács ◽  
Tibor Bíró ◽  
Csaba Berta ◽  
Mónika Duleba ◽  
Angéla Földi ◽  
...  
Keyword(s):  
Common Species ◽  
Danube River ◽  
Water Volume ◽  
Anthropogenic Pressures ◽  
The Danube River ◽  
Core Species ◽  
Epiphytic Communities ◽  
Tributary System ◽  
The Impact

Here we report the results of our decades-long study on epiphytic communities from two tributary systems of the Szigetköz section of the Danube River. The main goal of the investigation was to detect changes in the epiphytic communities at structural (core species, changes in the relative abundance of common species) and functional (trait changes) levels as a result of the most important anthropogenic effects on Szigetköz, i.e., hydro-morphological modifications. We also examined the impact of rehabilitation on the tributary systems in terms of ecological potential. We discovered that mainly motile diatom species characterized the epiphyton due to reduced water volume were introduced into the tributary system after the diversion of the Danube. The ecosystem stabilized in the rehabilitated section, while the non-rehabilitated section showed a worsening tendency, mainly in the parapotamic branches. Our long-term data sets may provide a good basis for comparisons of different aquatic ecosystems, to define changes in the abundance of core species and in the structure of community in response to different anthropogenic pressures. It is fundamental to determine adaptive traits in assessing the impact of global warming stressors on biodiversity.

scholarly journals Prediction of Water Quality in the Danube River Under extreme Hydrological and Temperature Conditions

2009 ◽  
Vol 57 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Pavla Pekárová ◽  
Milan Onderka ◽  
Ján Pekár ◽  
Peter Rončák ◽  
Pavol Miklánek
Keyword(s):  
Water Quality ◽  
Water Resources ◽  
Water Temperature ◽  
Danube River ◽  
The Danube River ◽  
Temperature Conditions ◽  
Water Quality Variables ◽  
Time Flow ◽  
The Impact

Prediction of Water Quality in the Danube River Under extreme Hydrological and Temperature ConditionsOne of the requirements imposed by the Water Framework Directive (WFD, 2000/60/EC) is to analyze and predict how quality of surface waters will evolve in the future. In assessing the development of a stream's pollution one must consider all sources of pollution and understand how water quality evolves over time. Flow and water temperature regime of a stream or river are the main factors controlling the extent to which deterioration of a stream's water quality can propagate under constant input from pollution sources. In addition, there is ever increasing public concern about the state of the aquatic environment. Decision makers and scientists involved in water management call for studies proposing simulation models of water quality under extreme natural hydrologic and climatic scenarios. Also, human impact on water resources remain an issue for discussion, especially when it comes to sustainability of water resources with respect to water quality and ecosystem health. In the present study we investigate the long-term trends in water quality variables of the Danube River at Bratislava, Slovakia (Chl-a, Ca, EC, SO2-, Cl-, O2, BOD5, N-tot, PO4-P, NO3-N, NO2-N, etc.), for the period 1991-2005. Several SARIMA models were tested for the long-term prediction of selected pollutant concentrations under various flow and water temperature conditions. In order to create scenarios of selected water quality variables with prediction for 12 months ahead, three types of possible hydrologic and water temperature conditions were defined: i) average conditions - median flows and water temperature; ii) low flows and high water temperature; and iii) high flows and low water temperature. These conditions were derived for each month using daily observations of water temperature and daily discharge readings taken in the Danube at Bratislava over the period 1931-2005 in the form of percentiles (1th-percentile, median, 99th-percentile). Once having derived these extreme-case scenarios, we used selected Box-Jenkins models (with two regressors - discharge and water temperature) to simulate the extreme monthly water quality variables. The impact of natural and man-made changes in a stream's hydrology on water quality can be readily well simulated by means of autoregressive models.

scholarly journals Is the Water Temperature of the Danube River at Bratislava, Slovakia, Rising?

2008 ◽  
Vol 9 (5) ◽  
pp. 1115-1122 ◽  
Author(s):  
Pavla Pekarova ◽  
Dana Halmova ◽  
Pavol Miklanek ◽  
Milan Onderka ◽  
Jan Pekar ◽  
...  
Keyword(s):  
Time Series ◽  
Water Temperature ◽  
Heat Load ◽  
Empirical Relationship ◽  
Danube River ◽  
Average Heat ◽  
The Danube River ◽  
Average Temperature ◽  
Monthly Discharge

Abstract This paper aims to reveal the annual regime, time series, and long-term water temperature trends of the Danube River at Bratislava, Slovakia, between the years 1926 and 2005. First, the main factors affecting the river’s water temperature were identified. Using multiple regression techniques, an empirical relationship is derived between monthly water temperatures and monthly atmospheric temperatures at Vienna (Hohe Warte), Austria, monthly discharge of the Danube, and some other factors as well. In the second part of the study, the long-term trends in the annual time series of water temperature were identified. The following series were evaluated: 1) The average annual water temperature (To) (determined as an arithmetic average of daily temperatures in the Danube at Bratislava), 2) the weighted annual average temperature values (Toυ) (determined from the daily temperatures weighted by the daily discharge rates at Bratislava), and 3) the average heat load (Zt) at the Bratislava station. In the long run, the To series is rising; however, the trend of the weighted long-term average temperature values, Toυ, is near zero. This result indicates that the average heat load of the Danube water did not change during the selected period of 80 yr. What did change is the interannual distribution of the average monthly discharge. Over the past 25 yr, an elevated runoff of “cold” water (increase of the December–April runoff) and a lower runoff of “warm” water (decrease of the river runoff during the summer months of June–August) were observed.

scholarly journals Functional diversity of phytoplankton highlights long-term gradual regime shift in the middle section of the Danube River due to global warming, human impacts and oligotrophication

2018 ◽  
Vol 63 (5) ◽  
pp. 456-472 ◽  
Author(s):  
András Abonyi ◽  
Éva Ács ◽  
András Hidas ◽  
István Grigorszky ◽  
Gábor Várbíró ◽  
...  
Keyword(s):  
Global Warming ◽  
Functional Diversity ◽  
Regime Shift ◽  
Human Impacts ◽  
Danube River ◽  
Middle Section ◽  
The Danube River

Changes in the Quality of the Danube River Water in the Section Smederevo-Kladovo in the Conditions of Backwater Effects

1990 ◽  
Vol 22 (5) ◽  
pp. 181-188 ◽  
Author(s):  
M. Peršić ◽  
M. Miloradov ◽  
V. Tutundžić ◽  
Z. Čukić
Keyword(s):  
River Water ◽  
Danube River ◽  
Hydropower Plant ◽  
Biochemical Processes ◽  
The Danube River ◽  
Global View ◽  
Physico Chemical ◽  
Composition And Structure

The paper describes specific changes in the quality of the Danube river water under the conditions of backwater effects in the Hydropower Plant Djerdap I storage. The results of longterm tests in five profiles of the investigated section, at various discharges give a global view of the intensity of changes in the composition of water mass. The analysis included changes in the contents of: organic matter, oxygen regime, reduction of turbidity and changes in the composition and abundance of plankton. The specific changes in the domain of physico-chemical and biochemical processes and changes in the biological status of the watercourse (composition and structure of plankton) at varying retention times complete the picture of short-term changes in the investigated system. Presentation of some settling effects and processes in the sediment of the storage provides an idea of some long-term changes in the conditions of backwater effects of the Danube in the investigated section.

Long-term monitoring of the Danube river—Sampling techniques, radionuclide metrology and radioecological assessment

2009 ◽  
Vol 67 (5) ◽  
pp. 894-900 ◽  
Author(s):  
F.J. Maringer ◽  
V. Gruber ◽  
M. Hrachowitz ◽  
A. Baumgartner ◽  
S. Weilner ◽  
...  
Keyword(s):  
Danube River ◽  
Sampling Techniques ◽  
The Danube River ◽  
Long Term Monitoring ◽  
Radionuclide Metrology ◽  
Term Monitoring
Sign in / Sign up

Export Citation Format

Share Document