IMPROVEMENT OF THE METHOD FOR ASSESSMENT OF THE HETEROTROPHIC ACTIVITY OF FRESHWATER BACTERIA BY STUDYING HOW BACTERIAL COMMUNITY CONSUMES THE ORGANIC MATTER EXCRETED BY ALGAE: ISSUES OF WATER QUALITY

Fisheries ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. 61-66 ◽  
Author(s):  
Anatoly Sadchikov
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Aquatic Ecosystems ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Trophic Levels ◽  
Organic Substances ◽  
Heterotrophic Activity ◽  
Freshwater Bacteria ◽  
Methods And Techniques

The article describes an improved and approved methodology for assessing the heterotrophic activity of freshwater bacteria using a specific example. Namely, the example of studying the bacterial consumption of organic matter excreted by algae. Utilization of organic substances in water bodies by microorganisms and their oxidation are an important part of the functioning of aquatic ecosystems and water self-purification. This article details innovative modifications to the method based on the use of 14C-labeled organic matter by aquatic organisms. All these methods and techniques have been tested in the study of production and destruction processes in freshwater ecosystems of different trophic levels including mesotrophic, eutrophic and hypertrophic surface ecosystems.

scholarly journals Fungi and viruses as important players in microbial mats

2020 ◽  
Vol 96 (11) ◽  
Author(s):  
Cátia Carreira ◽  
Christian Lønborg ◽  
Michael Kühl ◽  
Ana I Lillebø ◽  
Ruth-Anne Sandaa ◽  
...  
Keyword(s):  
Organic Matter ◽  
Aquatic Ecosystems ◽  
Microbial Mats ◽  
Freshwater Ecosystems ◽  
Food Web Structure ◽  
Element Cycling ◽  
Functional Roles ◽  
Web Structure ◽  
Experimental Approaches ◽  
And Function

ABSTRACT Microbial mats are compacted, surface-associated microbial ecosystems reminiscent of the first living communities on early Earth. While often considered predominantly prokaryotic, recent findings show that both fungi and viruses are ubiquitous in microbial mats, albeit their functional roles remain unknown. Fungal research has mostly focused on terrestrial and freshwater ecosystems where fungi are known as important recyclers of organic matter, whereas viruses are exceptionally abundant and important in aquatic ecosystems. Here, viruses have shown to affect organic matter cycling and the diversity of microbial communities by facilitating horizontal gene transfer and cell lysis. We hypothesise fungi and viruses to have similar roles in microbial mats. Based on the analysis of previous research in terrestrial and aquatic ecosystems, we outline novel hypotheses proposing strong impacts of fungi and viruses on element cycling, food web structure and function in microbial mats, and outline experimental approaches for studies needed to understand these interactions.

scholarly journals Biological factors of water quality in a mesotrophic ecosystem

Fisheries ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. 16-19
Author(s):  
Anatoliy Sadchikov ◽  
Sergei Ostroumov
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Aquatic Environment ◽  
Aquatic Ecosystems ◽  
Biological Factors ◽  
Physiological Processes ◽  
Negative Effect

Dissolved organic matter (DOM) is one of the important parameters of water quality in aquatic ecosystems. In the experiments, phyto- and bacterioplankton actively consumed 14C-labeled chlorella hydrolyzate. Removal (by filtration) of cyanobacteria from the aquatic environment leads to an increase in the rate of DOM consumption by bacteria. This indicates the possibility of a negative effect of cyanobacterial metabolites on the physiological processes of bacterioplankton.

scholarly journals Dynamics of Water Quality of the Tsimlyansk Reservoir over the 1979-2014 Period.

2016 ◽  
pp. 74
Author(s):  
Keyword(s):  
Water Quality ◽  
Aquatic Organisms ◽  
Water Quality Assessment ◽  
Ammonia Nitrogen ◽  
Biogenic Elements ◽  
Chemical Information ◽  
Organic Substances ◽  
Reservoir Water ◽  
Tsimlyansk Reservoir ◽  
Vital Functions

Analysis of many-year hydro/chemical information of the Rosgidroment state observation network that enables to assess the changes in the pollutants typical for the Tsimlyansk reservoir over the 1979–2014 period has been carried on the basis of a single methodological/methodical framework. The easily oxidizable organic substances dynamics (by BOD5) and organic substances (by COD), as well as changing of many-year season concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen and phosphates has been studied as they are the most active substances contributing to aquatic organisms vital functions in view of the cyanobacteriae-caused “blooming” typical for the Tsimlyansk reservoir. These biogenic elements’ concentration in water mostly depends on activity of the biological processes occurring within water bodies. It has been demonstrated that seasonal variations are characteristic for the organic matter, nitrogen and phosphorous mineral forms content in the Tsimlyansk reservoir water, and increase in their content can promote its euthrophication.Comparison of the observed data with the maximal permissible concentration values were used for the water quality assessment. An integrated assessment of the Tsimlyansk reservoir water quality dynamics has been accomplished at the most human affected ranges. Some trends of the Tsimlyansk reservoir monitoring system improvement in the conditions of the complicated hydrological situation caused by the 2010-2014 low-water period in the Don basin have been outlined: in particular, joint functioning of hydro/chemical and hydro/biological observation stations with hydrological stations. Bearing in mind that the in-reservoir processes of chemical substances transformation and redistribution are critical for the reservoir aquatic ecosystem functioning and sustainability it is very important to study exchange processes within the water-bottom sediments system.

scholarly journals Reviews and Syntheses: Effects of permafrost thaw on arctic aquatic ecosystems

2015 ◽  
Vol 12 (13) ◽  
pp. 10719-10815 ◽  
Author(s):  
J. E. Vonk ◽  
S. E. Tank ◽  
W. B. Bowden ◽  
I. Laurion ◽  
W. F. Vincent ◽  
...  
Keyword(s):  
Organic Matter ◽  
Aquatic Ecosystems ◽  
Soil Layer ◽  
Freshwater Ecosystems ◽  
The Arctic ◽  
Food Web Structure ◽  
Thermokarst Lakes ◽  
Freshwater Systems ◽  
Permafrost Thaw ◽  
Lake Morphology

Abstract. The Arctic is a water-rich region, with freshwater systems covering 16 % of the northern permafrost landscape. The thawing of this permafrost creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current state of knowledge regarding how permafrost thaw affects lentic and lotic systems, exploring the effects of both thermokarst (thawing and collapse of ice-rich permafrost) and deepening of the active layer (the surface soil layer that thaws and refreezes each year). Within thermokarst, we further differentiate between the effects of thermokarst in lowland areas, vs. that on hillslopes. For almost all of the processes that we explore, the effects of thaw vary regionally, and between lake and stream systems. Much of this regional variation is caused by differences in ground ice content, topography, soil type, and permafrost coverage. Together, these modifying variables determine the degree to which permafrost thaw manifests as thermokarst, whether thermokarst leads to slumping or the formation of thermokarst lakes, and the manner in which constituent delivery to freshwater systems is altered by thaw. Differences in thaw-enabled constituent delivery can be considerable, with these modifying variables determining, for example, the balance between delivery of particulate vs. dissolved constituents, and inorganic vs. organic materials. Changes in the composition of thaw-impacted waters, coupled with changes in lake morphology, can strongly affect the physical and optical properties of thermokarst lakes. The ecology of thaw-impacted systems is also likely to change, with thaw-impacted lakes and streams having unique microbiological communities, and showing differences in respiration, primary production, and food web structure that are largely driven by differences in sediment, dissolved organic matter and nutrient delivery. The degree to which thaw enables the delivery of dissolved vs. particulate organic matter, coupled with the composition of that organic matter and the morphology and stratification characteristics of recipient systems will play an important role in determining the balance between the release of organic matter as greenhouse gases (CO2 and CH4), its burial in sediments, and its loss downstream. The magnitude of thaw impacts on northern aquatic ecosystems is increasing, as is the prevalence of thaw-impacted lakes and streams. There is therefore an urgent need to address the key gaps in understanding in order to predict the full effects of permafrost thaw on aquatic ecosystems throughout the Arctic, and their consequential feedbacks to climate.

scholarly journals Influences of nanoparticles on aquatic organisms: Current situation of nanoparticles effects in aquatic ecosystems

2021 ◽  
Vol 3 (1) ◽  
pp. 54-60
Author(s):  
Didem Gökçe
Keyword(s):  
Aquatic Ecosystems ◽  
Aquatic Organisms ◽  
High Reactivity ◽  
Freshwater Ecosystems ◽  
Engineered Nanoparticles ◽  
Adverse Impacts ◽  
Wide Range ◽  
Mean Size ◽  
Level Of Aggregation ◽  
Physical And Chemical

The quick improvement of nanotechnology permits a wide range of utilization of engineered nanoparticles, such as personal care products, medicals, optics, electronics, and automobiles. The nanoparticles manufactured from Ag, Au carbon-nanotube, ZnO, SiO2, TiO2, Cu, Ni, and magnetic ferrites are among the generally utilized in products. The nanoparticles are produced and utilized in large quantities and release into marine and freshwater ecosystems during production, use, discharge, treatment, and deposition. Those particles with a mean size of 1 nm - 100 nm are of potential environmental risks because of their particular qualifications and high reactivity although their great economical values. Based on the studies, the size, shape, and surface physical and chemical characteristics of the nanoparticles show the level of aggregation, solubility, structural and chemical composition, the importance of the use of nanoparticles, and their toxicity with biological systems. Nanoparticles can potentially cause adverse impacts on tissue, cellular, genetic materials, and protein- enzyme levels due to their unique physical and chemical qualifications. In this study, the effects of nanoparticles on aquatic organisms and aquatic ecosystems were evaluated.

scholarly journals Effects of salinity changes on aquatic organisms in a multiple stressor context

2018 ◽  
Vol 374 (1764) ◽  
pp. 20180011 ◽  
Author(s):  
Josefa Velasco ◽  
Cayetano Gutiérrez-Cánovas ◽  
María Botella-Cruz ◽  
David Sánchez-Fernández ◽  
Paula Arribas ◽  
...  
Keyword(s):  
Aquatic Ecosystems ◽  
Synergistic Effects ◽  
Experimental Studies ◽  
Aquatic Organisms ◽  
Joint Effect ◽  
Freshwater Ecosystems ◽  
Ion Concentration ◽  
Joint Effects ◽  
Multiple Stressor ◽  
Meta Analyses

Under global change, the ion concentration of aquatic ecosystems is changing worldwide. Many freshwater ecosystems are being salinized by anthropogenic salt inputs, whereas many naturally saline ones are being diluted by agricultural drainages. This occurs concomitantly with changes in other stressors, which can result in additive, antagonistic or synergistic effects on organisms. We reviewed experimental studies that manipulated salinity and other abiotic stressors, on inland and transitional aquatic habitats, to (i) synthesize their main effects on organisms' performance, (ii) quantify the frequency of joint effect types across studies and (iii) determine the overall individual and joint effects and their variation among salinity–stressor pairs and organism groups using meta-analyses. Additive effects were slightly more frequent (54%) than non-additive ones (46%) across all the studies ( n = 105 responses). However, antagonistic effects were dominant for the stressor pair salinity and toxicants (44%, n = 43), transitional habitats (48%, n = 31) and vertebrates (71%, n = 21). Meta-analyses showed detrimental additive joint effects of salinity and other stressors on organism performance and a greater individual impact of salinity than the other stressors. These results were consistent across stressor pairs and organism types. These findings suggest that strategies to mitigate multiple stressor impacts on aquatic ecosystems should prioritize restoring natural salinity concentrations. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.

Dominant aquatic species and their hydrological niches in freshwater ecosystems in a developing city

2019 ◽  
Vol 70 (5) ◽  
pp. 615
Author(s):  
S. Yang ◽  
T. Pan ◽  
X. Wang ◽  
Y. Sun ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Food Web ◽  
Water Resource Management ◽  
Keystone Species ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Trophic Levels ◽  
Food Web Structure ◽  
Spatial And Temporal Scales ◽  
Web Structure ◽  
Jinan City

Maintenance of appropriate hydrological niches is crucial to aquatic organisms. This study identified keystone species using the Ecopath with Ecosim food web model for hydrological niche analysis in Jinan City, the first pilot city of the Water Ecological Civilisation Project in China. The niche breadth of keystone species was analysed using Levins’ breadth model. Results revealed 35 keystone species in the aquatic ecosystems of Jinan City, including 5 phytoplankton, 7 zooplankton, 9 zoobenthos and 14 fish species. Streamflow was the most important hydrological factor affecting the phytoplankton, zooplankton, zoobenthos and fish communities in the study area, and excess variation in streamflow had an adverse effect on the normal evolution of the four biotic communities. We found that: (1) higher trophic levels in the food web contained more keystone species in the corresponding community; (2) carbon is an important element constraining the food web structure, and the magnitude of its effect on energy flow determines the degree of importance of the keystone species in the food web; and (3) changes to the survey season and at the spatiotemporal scale will have strong effects on the results of hydrological niche analysis and, to reduce these effects, it will be important to lengthen the spatial and temporal scales to cover both dry and flood seasons in the future. These results may provide an important basis for decision making regarding ecological scheduling and remediation of rivers in the study area, and potentially regions worldwide, thus facilitating aquatic ecological remediation and sustainable water resource management.

scholarly journals САНІТАРНО-ГІДРОБІОЛОГІЧНА ХАРАКТЕРИСТИКА ОЗЕРА ВЕРБНЕ ЗА МІКРОФІТОБЕНТОСОМ

2019 ◽  
Vol 77 (3) ◽  
pp. 46-51
Author(s):  
O. A. Davydov ◽  
D. P. Larionova
Keyword(s):  
Water Quality ◽  
Human Factors ◽  
Aquatic Ecosystems ◽  
Aquatic Organisms ◽  
Benthic Algae ◽  
Algal Communities ◽  
Quality Classification ◽  
Lake Bottom ◽  
Water Quality Classification ◽  
Quality Category

Assessing ecological and sanitary state of aquatic ecosystems, including their trophic and saprobiological status and impact of human factors, is among key objectives in modern hydrobiology. Apart from common hydrobiological methods (identifying species compositions, calculating algae number and biomass etc), there are specific methods for the assessment of aquatic ecosystems. Bioindication, which is based on aquatic organisms’ response to environmental factors, including human factors, is the most important. Microphytobenthos is highly sensitive to changes in natural and human factors. Its bioindication capabilities are widely known, therefore studying them as part of sanitary and hydrobiological characteristics of various water bodies is of great interest. Water basins across the City of Kyiv are under diversified human impact including various factors and effects, which differ in pressure degree. Thus, using microphytobenthos for sanitary and hydrobiological assessment, even within one type of water basins, has certain aspects, which depend on the bottom algal communities’ stability or degree of transformation. It is often caused by trophic and topic competition between microphytobenthos, phytoplankton and higher aquatic plants, as the latter two can inhibit growth of bottom algae. In the view of the above, special attention should be paid to quantitative characteristics of benthonts, which may act as cenose-forming organisms. The paper examines the findings of the studies on microphytobenthos in Verbne Lake, which is affected by negative human factor – contamination by surface and ground flow from Kyiv City area and is intensively used for recreation. The objective is to study the sanitary and hydrobiological characteristics and ecological quality of Verbne Lake according to microphytobenthos’ biondication indices. Benthic algae were sampled with the MB-TE microbenthometer within the littoral zone in triplicate from the total area of 40 cm2. Algae number was calculated on a counting plate in a 0.1 cm3 drop, their biomass was calculated according to geometric similarity method. Trophic and saprobiological values were assessed in accordance with the scale, proven for microphytobenthos. Saprobity index was calculated according to the Pantle-Buck method in Sladecek modification on the grounds of traditional and modern data on saprobity indicator algae. Benthonts, planktonts and periphytonts were distinguished with consideration taken of their association with particular habitats. Ecological classification of water quality was performed on the grounds of saprobity bioindication (saprobity indices) according to microphytobenthos. For microphytobenthos’ structural components their role in species richness, number and biomass were analyzed. Proceeding from the obtained findings, sanitary and hydrobiological characteristics of Verbne Lake were presented according to microphytobenthos. On the whole, the lake can be classified as mesotrophic, β-mesosaprobic water body. Benthonts proved to play an essential part in forming microphytobenthos’ indicatory characteristics. Intensive phytoplankton growth in the water column and its sedimentation upon the lake bottom inhibit development of benthic algal forms. In accordance with the ecological water quality classification based on microphytobenthos saprobity bioindication results (saprobity indices), the water of Verbne Lake relates to Water Quality Class II, Water Quality Category 3. The most unfavorable situation within the lake’s littoral area was registered in summer, which signals that self-purification processes are becoming less intensive and the aquatic ecosystem state is getting worse.

scholarly journals Influence of sea cucumbers on chromophoric of dissolved organic matter in multitrophic aquaculture tanks

2017 ◽  
Author(s):  
Seyed Mohammad Sadeghi-Nassaj ◽  
Teresa S. Catalá ◽  
Pedro A. Álvarez ◽  
Isabel Reche
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Aquatic Ecosystems ◽  
Light Transmission ◽  
Optical Parameters ◽  
Absorption Coefficients ◽  
Sea Cucumbers ◽  
Anemonia Sulcata ◽  
High Concentrations

Background. The effluents of the mono-specific aquaculture contain high concentrations of dissolved nutrients and organic matter, which affect negatively water quality of the recipient aquatic ecosystems. A key feature of water quality is its transparency. Chromophoric dissolved organic matter (CDOM) determines most of the light transmission in the ultraviolet and blue bands in the aquatic ecosystems. A sustainable alternative to mono-specific aquaculture is the integrated multitrophic aquaculture that includes species trophically complementary named “extractive” species. Sea cucumbers are recognized as efficient extractive species, with a high potential to improve water quality, due to the consumption of particulate organic matter (POM). However, the effects of sea cucumbers on CDOM are still unknown. Methods. During one year, we biweekly monitored CDOM in two aquaculture tanks with different trophic structure. One of the tanks (-holothurian tank) only contained the primary species, Anemonia sulcata, whereas the other tank (+ holothurian tank) also contained individuals of Holothuria tubulosa and H. forskali. We routinely performed CDOM absorption spectra from 200 nm to 750 nm and determined quantitative (absorption coefficients at 325 nm) and qualitative (spectral slopes and molar absorption coefficients at 325 nm) optical parameters in the inlet waters, in the tanks, and in their corresponding effluents. Results. Absorption coefficients at 325 nm (a325) and spectral slopes from 275 to 295 nm (S275-295) were significantly lower in the effluents of the +holothurian tank (average: 0.33 and 16 μm-1, respectively) than in the effluents of the −holothurian tank (average: 0.69 m-1 and 34 μm-1, respectively), being the former similar to those found in the inlet waters (average: 0.32 m-1 and 22 μm-1, respectively). This reduction in CDOM absorption appears to be mediated by the POM consumption by the holothurians. The reduction of POM concentration in the +holothurian tank may weaken the process of POM disaggregation into dissolved organic matter, which ultimately might have generated CDOM in the –holothurian tank. Discussion. Extractive species such as holothurians improve water transparency through POM consumption, likely because reduces POM disaggregation into CDOM. We suggest that CDOM monitoring in aquaculture facilities, using automatic probes or even remote sensing, could be a useful tool to trace the effectiveness of extractive species at large scales of time and space.

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