scholarly journals Assessment of River-Sea Interaction in the Danube Nearshore Area (Ukraine) by Bioindicators and Statistical Mapping

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 310
Author(s):  
Anastasiia Snigirova ◽  
Yuliya Bogatova ◽  
Sophia Barinova

There is a lack of understanding of the main drivers that form the picture of biological communities of transitional waters in deltaic ecosystems under the influence of terrestrial sources. Analysis of hydrochemical parameters in relation to phytoplankton communities in the Ukrainian part of the Danube coastal zone (in August 2018) is the focus of current work. The goal was to identify patterns in the distribution of environmental parameters (salinity and nutrients) in the area of the shipping channel through the Bystry arm, as well as to assess the state of water quality. The ecological bioindicators approach using modern statistical methods, and ecological mapping shows sufficient achievements in interpreting the results. The indicators of salinity (mesohalobes) had better describe the character of the transportation of fresh riverine waters than salinity gradient. The composition of 35 indicator phytoplankton species corresponds to 3 and 4 water quality classes in the coastal zone. High N:P ratios showed an imbalance in the ecosystem as an indicator of production and destruction processes. Statistical maps of the indicator species distribution revealed the river current’s influence on the nearshore water mass. Ecological maps of surface and bottom variables show various environmental impacts resulting from dredging in the shipping channel and excavated soil dumping. Canonical correspondence analysis (CCA) and statistical maps revealed two pools of factors with oppositely directed effects on phytoplankton: salinity, on one hand, and nutrients, on the other. Miozoa and Chlorophyta have an opposite interaction with salinity and oxygen and can be ecosystem change indicators in further analysis

2020 ◽  
Vol 42 ◽  
pp. e2
Author(s):  
Evandro Oscar Mafra ◽  
Eduardo Werneck ◽  
Viviane Tranker ◽  
Aline Pereira Gomes

The Itajaí-Mirim River located in Santa Catarina, in the region of the low estuary of the Itajaí-Açu River, is the place where most of the water supplied for consumption is consumed by the Municipalities of Itajaí and Navegantes, the São Roque catchment station. This study aims to analyze the water quality in the Itajaí-Mirim river before and after the implantation of the dam in the Itajaí-Mirim river, based on a monitoring of physical-chemical parameters. The collections described in this report were carried out at six sample points, from January to December 2007, with the purpose of physically and chemically characterizing the environment in the rectified channel and, also, in the original bed of Itajaí-Mirim. The parameters measured in situ serve to assess the general state of water quality at the time of sampling. The main parameters measured, four of them deserve special attention (pH, Turbidity, Dissolved Oxygen and Salinity) and the correlated environmental parameters were flow rate and precipitation. In general, depending on the main results obtained, the analyzed waters can be classified in Class 2 of fresh waters, according to the limit values of CONAMA Resolution No. 357/05, and for the sampled period, precipitation and flow influenced the water quality.


Author(s):  
Roksana Jahan ◽  
Hyu Chang Choi ◽  
Young Seuk Park ◽  
Young Cheol Park ◽  
Ji Ho Seo ◽  
...  

Self-Organizing Maps (SOM) have been used for patterning and visualizing ten environmental parameters and phytoplankton biomass in a mactrotidal (>10 m) Gyeonggi Bay and artificial Shihwa Lake during 1986–2004. SOM segregated study areas into four groups and ten subgroups. Two strikingly alternative states are frequently observed: the first is a diverse non-eutrophic state designated by three groups (SOM 1–3), and the second is a eutrophic state (SOM 4: Shihwa Lake and Upper Gyeonggi Bay; summer season) characterized by enhanced nutrients (3 mg l−1 dissolved inorganic nitrogen, 0.1 mg l−1 PO4) that act as a signal and response to that signal as algal blooms (24 µg chlorophyll-a l−1). Bloom potential in response to nitrification is affiliated with high temperature (r = 0.26), low salinity (r = −0.40) and suspended solids (r = –0.27). Moreover, strong stratification in the Shihwa Lake has accelerated harmful algal blooms and hypoxia. The non-eutrophic states (SOM 1–3) are characterized by macro-tidal estuaries exhibiting a tolerance to pollution with nitrogen-containing nutrients and retarding any tendency toward stratification. SOM 1 (winter) is more distinct from SOM 4 due to higher suspended solids (>50 mg l−1) caused by resuspension that induces light limitation and low chlorophyll-a (<5 µg l−1). In addition, eutrophication-induced shifts in phytoplankton communities are noticed during all the seasons in Gyeonggi Bay. Overall, SOM showed high performance for visualization and abstraction of ecological data and could serve as an efficient ecological map that can specify blooming regions and provide a comprehensive view on the eutrophication process in a macrotidal estuary.


2013 ◽  
Vol 46 (1) ◽  
pp. 333-347 ◽  
Author(s):  
Antonino Maltese ◽  
Fulvio Capodici ◽  
Giuseppe Ciraolo ◽  
Goffredo La Loggia

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 73
Author(s):  
Buhari Lawan Muhammad ◽  
Taehee Kim ◽  
Jang-Seu Ki

Biomonitoring of phytoplankton communities in freshwater ecosystems is imperative for efficient water quality management. In the present study, we present the seasonal diversity of phytoplankton from the non-reservoir area of the Han River (Korea), assessed using the 18S rRNA amplicon sequencing. Our results uncovered a considerably high eukaryotic diversity, which was predominantly represented by phytoplankton in all the seasons (38–63%). Of these, the diatoms, Cyclostephanos tholiformis, Stephanodiscus hantzschii, and Stephanodiscus sp., were frequently detected in spring and winter. Interestingly, for the first time in the Han River, we detected a large number of operational taxonomic unit (OTU) reads belonging to the naked dinoflagellate Gymnodinium sp., which dominated in autumn (15.8%) and was observed only in that season. Molecular cloning and quantitative real-time polymerase chain reaction (PCR) confirmed the presence of Gymnodinium sp. in the samples collected in 2012 and 2019. Moreover, a comparison of the present data with our previous data from a reservoir area (Paldang Dam) revealed similar patterns of phytoplankton communities. This molecular approach revealed a prospective toxic species that was not detected through microscopy. Collectively, resolving phytoplankton communities at a level relevant for water quality management will provide a valuable reference for future studies on phytoplankton for environmental monitoring.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tahnee Manning ◽  
Arjun Venkatesh Thilagaraj ◽  
Dmitri Mouradov ◽  
Richard Piola ◽  
Clare Grandison ◽  
...  

Abstract Background Dinoflagellates are a ubiquitous and ecologically important component of marine phytoplankton communities, with particularly notable species including those associated with harmful algal blooms (HABs) and those that bioluminesce. High-throughput sequencing offers a novel approach compared to traditional microscopy for determining species assemblages and distributions of dinoflagellates, which are poorly known especially in Australian waters. Results We assessed the composition of dinoflagellate assemblages in two Australian locations: coastal temperate Port Phillip Bay and offshore tropical waters of Davies Reef (Great Barrier Reef). These locations differ in certain environmental parameters reflecting latitude as well as possible anthropogenic influences. Molecular taxonomic assessment revealed more species than traditional microscopy, and it showed statistically significant differences in dinoflagellate assemblages between locations. Bioluminescent species and known associates of HABs were present at both sites. Dinoflagellates in both areas were mainly represented by the order Gymnodiniales (66%—82% of total sequence reads). In the warm waters of Davies Reef, Gymnodiniales were equally represented by the two superclades, Gymnodiniales sensu stricto (33%) and Gyrodinium (34%). In contrast, in cooler waters of Port Phillip Bay, Gymnodiniales was mainly represented by Gyrodinium (82%). In both locations, bioluminescent dinoflagellates represented up to 0.24% of the total sequence reads, with Protoperidinium the most abundant genus. HAB-related species, mainly represented by Gyrodinium, were more abundant in Port Phillip Bay (up to 47%) than at Davies Reef (28%), potentially reflecting anthropogenic influence from highly populated and industrial areas surrounding the bay. The entire assemblage of dinoflagellates, as well as the subsets of HAB and bioluminescent species, were strongly correlated with water quality parameters (R2 = 0.56–0.92). Significant predictors differed between the subsets: HAB assemblages were explained by salinity, temperature, dissolved oxygen, and total dissolved solids; whereas, bioluminescent assemblages were explained only by salinity and dissolved oxygen, and had greater variability. Conclusion High-throughput sequencing and genotyping revealed greater diversity of dinoflagellate assemblages than previously known in both subtropical and temperate Australian waters. Significant correlations of assemblage structure with environmental variables suggest the potential for explaining the distribution and composition of both HAB species and bioluminescent species.


2012 ◽  
Vol 64 (2) ◽  
pp. 745-755
Author(s):  
Jelena Rakocevic

Qualitative and quantitative phytoplankton compositions of 10 Montenegrin lakes were investigated in the summer of 2007. The obtained results were compared with a previous study-period that was undertaken two decades ago. In the first period, diatoms numerically dominated the phytoplankton community in all studied lakes, while in the second period, the same was observed only in three of the ten lakes; in other studied lakes the relative contributions of green algae, dinoflagellates and/or cyanobacteria increased, while the contribution of diatoms decreased. The shift observed in phytoplankton composition and diversity in some of the studied lakes indicates an increase in the trophic level over the two decades. The sustainable management plan of the aquatic ecosystems in Montenegro should include the establishment of an environmental monitoring system in order to record any alterations that may take place in water quality.


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