Water Quality of the Odra (Oder) River before and during the Ecological Disaster in 2022: A Warning to Water Management

This work presents a case study accompanied by an analysis of potential reasons for fish mortality in the lower Oder River during an ecological disaster in August 2022. Changes in physicochemical water quality indicators indicate that fish and benthic organism death was likely due to the creation of hypoxia. The research also highlighted the trophic threats to the studied Oder River section linked to the disaster. The disaster occurred in the upper and middle Oder River, extending to the lower stretch. A physicochemical analysis of water samples revealed that the fish and organism death in the estuarine section was mainly due to reduced dissolved oxygen, caused by the decomposition of organic matter from the upper river sections. This was reinforced by high temperatures and low water levels. The negative trophic consequences of the described ecological disaster for the lower section of the Oder River may be long-term. Over thirty years of monitoring showed threats of excess biogenic compounds, organic matter, and bacterial contamination. Despite decreasing nitrogen and phosphorus, significant phytoplankton blooms implied internal nutrient sources. Considering climate change and the poor trophic status, recurrent disasters and deteriorating conditions are anticipated. Mitigation requires continuous monitoring, limiting the nutrient input (especially phosphorus), and preparing for extreme events. Geotechnical methods in the lower river can improve oxygen levels and fish survival.

Section: The Impact Of Hypoxia On Basic Water Quality Indicatorsmentioning

confidence: 67%

Threats to the Lower Section of the River after Fish Mortality in the Ecological Environment of the Oder River

Siwek,

Podlasińska

2023

“…An increase in salinity can result in the massive growth of species new to the habitat, such as Prymnesium parvum Carter, the blooms of which cause fish die-off worldwide [8]. This species caused an ecological disaster, a mass die-off of fish and mussels in the Oder River in Poland in 2022, facilitated by a prolonged period of low flows and high water temperature (>24 • C), salinity (maximum 1.4 g dm −3 ), and ammonia concentration (>4 mg dm −3 ) [17]. Therefore, our findings indicating conditions favouring high concentrations of major ions in mountain rivers may also be an important indication for other rivers.…”

Section: The Raba River Above the Reservoirmentioning

confidence: 99%

“…It affects various levels of ecosystem organisation [14]. Moreover, an increase in salinity may result in the mass development of species new to the habitat, which may endanger local biocenosis [8,17]. Therefore, the ability to predict changes in the major ion concentrations under different hydrological conditions is important for the appropriate management of running waters, water use opportunities, and ecosystem services.…”

Section: Introductionmentioning

confidence: 99%

Trends of Major Ions in a Carpathian River in Poland: The Influence of Flow and Damming

Szarek-Gwiazda

2024

Flow influences major ion concentrations in river water, therefore, it seems that it can differentiate ion concentrations in mountain rivers in different hydrological years. This study aimed to determine the impact of flow on the major ion concentrations in the Carpathian Raba River above and below the Dobczyce Reservoir (southern Poland) in hydrologically dry (HD), average (HA), and wet (HW) years (period April–October) in the period 2010–2017. In the river above the reservoir, the flow negatively affected the concentrations of most major ions under all hydrological conditions, which resulted in their significant differences between (1) the studied hydrological years (except for SO42−)–higher in the HD years than in the HA or HW years–and (2) seasons–higher Mg2+, Na+, K+, Cl−, and SO42− concentrations (mainly point sources of pollution) were identified in summer or autumn than in spring in the HD and HA years. The dam reservoir strongly modified the ion concentrations in the downstream river. It significantly decreased all major ion concentrations only in the HD years, when they were high in the upstream river, and Ca2+, Mg2+, or HCO3− concentrations in all the studied hydrological years. There, the ion concentrations were not related to the flow that resulted in their insignificant differences between the studied hydrological years (with the exception of HCO3−, Ca2+, and Cl−) and different seasonal changes to those in the river above the dam. The obtained results allow for predicting conditions favouring an increase in the salinity of mountain river waters; therefore, they are important for appropriate management and water use opportunities.

“…Simultaneous with low flows and increased water temperature, nutrient enrichment can lead to unexpected ecological disasters, such as in the case of the Odra River in 2022, where toxins released by the haptophyte golden algae, Prymnesium parvum, resulted in mass mortality among fish, bivalves, and water snails [113]. Thus, such water quality studies are particularly significant in the initial parts of stream systems, which are greatly vulnerable in terms of hydrochemical alteration and therefore crucial in appropriate water management [114].…”

Section: Recommendations and Limitationsmentioning

confidence: 99%

The Impact of Various Types of Cultivation on Stream Water Quality in Central Poland

Stępniewski,

Karger,

Łaszewski

2023

Agricultural practices have a significant impact on stream water quality in rural landscapes; however, there is still little empirical evidence of how different types of cultivation alter the hydrochemistry of running water. Thus, the current study explored the spatial dynamics of selected ion concentrations and their land cover dependence in lowland agricultural catchments. From November 2021 to October 2022, water samples were collected from 30 sites located across small tributaries of the rivers Bzura, Pilica, and Radomka for chemical analysis of their NO3, NO2, NH4, Ca, Mg, K, Na, As, Ba, Sr, and V concentrations. The results indicated a clear spatial heterogeneity of water quality, related to lithology and dominant land cover evaluated with the CORINE Land Cover 2018 dataset. Overall, sites representing agricultural land promoted increased concentrations of major and trace elements, while those with pepper cultivation were additionally contaminated with NO3 and NO2. The correlation performance for nitrogen compounds was the highest for narrower buffer zones, which was not documented for major and trace elements, which were linked more strongly with land cover at larger scales. Such new insights into the water quality dynamics of lowland agricultural catchments, being a simultaneous reflection of lithology, agricultural practices, and several municipal impacts, have significant implications for appropriate water management in rural landscapes.