scholarly journals Summer aspect of phytoplankton communities in some Montenegrin lakes: Are there changes after more than two decades?

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.

2020 ◽  
Vol 10 (1) ◽  
pp. 63-75
Author(s):  
Natalia S. Pribylovskaya ◽  
Tatsiana P. Marchik ◽  
Ekaterina A. Taranova

On the example of the small Lososna river (Grodno, Belarus), the changes in the phytoplankton community in urbanized areas for the period 2015–2018 are shown and compared with the data previously obtained in 2008. The species diversity of the Lososna river phytoplankton was represented by 87 species from six divisions dominated by Chlorophyta and Bacillariophyta (the algocenosis is dominated by the chlorophytic-diatom complex). There was an increase in species diversity relative to 2008 (36 species), which indicates a positive dynamic of reducing the inflow of pollutants into the watercourse. The calculated saprobity indices correspond to the β-mesosaprobic type, which makes it possible to attribute the water of the Lososna river to the 4th rank and III class of water quality (satisfactory purity), and to characterize changes in the ecosystem as reversible.


2016 ◽  
Vol 19 ◽  
pp. 52-56
Author(s):  
Adelakun Kehinde Moruff ◽  
Mu’azu Mohammed Mu’azu ◽  
Amali Rosemary Patric ◽  
Omotayo Olabode Lawrence

Biological assessment is a useful alternative for understanding the ecological quality of aquatic ecosystems because biological communities integrate the environmental effects of water. This work investigates the diversity and abundance of phytoplankton in the Upper Jebba Basin of the Niger River in Nigeria. We sampled phytoplanktons by dragging plankton nets at three stations from March to May 2015 for qualitative and quantitative samples. Qualitative plankton samples were collected by towing 55μm mesh hydrobios plankton nets just below the water surface for five minutes at each sampling station. Quantitative samples, on the other hand, were collected by filtering 100 litres of water fetched with a bucket through a 55μm mesh hydrobios net. Both samples were preserved separately in a 4% buffered formalin solution. A total of 3160 cells/ml of phytoplanktons from taxa were identified in the study. High dominance of Oscillatoria sp., Microcystis sp., Chlorella sp., Pediastrum sp. and Synendra indicate that this lake has high amount of organic waste, polluted predominantly by upstream concerns (i.e., mining, agricultural, and domestic) and should be monitored strictly by relevant agencies in order to additional reduced health hazards caused by these pollutants.HYDRO Nepal JournalJournal of Water, Energy and EnvironmentIssue: 19Page: 52-56


2021 ◽  
Author(s):  
Laurenţia Ungureanu ◽  
◽  
Daria Tumanova ◽  
Grigore Ungureanu ◽  
◽  
...  

The article presents the results on qualitative and quantitative indicators of phytoplankton of the Prut River lower sector within the Republic of Moldova in 2018-2020. In phytoplankton compositions 72 species were identified. Seasonal and long-term patterns of phytoplankton development have been established in Prut River lower sector. The numbers of phytoplankton changed within the limits 1,06 to 20,32 mln. cell/l, with biomass 1,23-21,64 g/m3. The values of saprobic indexes, estimated on the basis of species-indicators (52 species) from phytoplankton composition, which are in proportion of 58% typically β-mezosaprobic, confirm the following: the water quality of lower Prut River sector in the period 2018-2020 was satisfactory for the development of phytoplankton and was attributed mainly to II-III (good-moderately polluted) quality classes.


2021 ◽  
Vol 12 ◽  
Author(s):  
Osiris Díaz-Torres ◽  
José de Anda ◽  
Ofelia Yadira Lugo-Melchor ◽  
Adriana Pacheco ◽  
Danielle A. Orozco-Nunnelly ◽  
...  

Lake Cajititlán is a small, shallow, subtropical lake located in an endorheic basin in western Mexico. It is characterized by a strong seasonality of climate with pronounced wet and dry seasons and has been classified as a hypereutrophic lake. This eutrophication was driven by improperly treated sewage discharges from four municipal wastewater treatment plants (WWTPs) and by excessive agricultural activities, including the overuse of fertilizers that reach the lake through surface runoff during the rainy season. This nutrient rich runoff has caused algal blooms, which have led to anoxic or hypoxic conditions, resulting in large-scale fish deaths that have occurred during or immediately after the rainy season. This study investigated the changes in the phytoplankton community in Lake Cajititlán during the rainy season and the association between these changes and the physicochemical water quality and environmental parameters measured in the lake’s basin. Planktothrix and Cylindrospermopsis were the dominant genera of the cyanobacterial community, while the Chlorophyceae, Chrysophyceae, and Trebouxiophyceae classes dominated the microalgae community. However, the results showed a significant temporal shift in the phytoplankton communities in Lake Cajititlán induced by the rainy season. The findings of this study suggest that significant climatic variations cause high seasonal surface runoff and rapid changes in the water quality (Chlorophyll-a, DO, NH4+, and NO3–) and in variations in the composition of the phytoplankton community. Finally, an alternation between phosphorus and nitrogen limitation was observed in Lake Cajititlán during the rainy season, clearly correlating to the presence of Planktothrix when the lake was limited by phosphorus and to the presence of Cylindrospermopsis when the lake was limited by nitrogen. The evidence presented in this study supports the idea that the death of fish in Lake Cajititlán could be mainly caused by anoxia, caused by rapid changes in water quality during the rainy season. Based on our review of the literature, this is the first study on the phytoplankton community in a subtropical lake during the rainy season using high throughput 16S rRNA and 18S rRNA amplicon sequencing.


2015 ◽  
Vol 12 (8) ◽  
pp. 2395-2409 ◽  
Author(s):  
C. J. Daniels ◽  
A. J. Poulton ◽  
M. Esposito ◽  
M. L. Paulsen ◽  
R. Bellerby ◽  
...  

Abstract. The spring bloom is a key annual event in the phenology of pelagic ecosystems, making a major contribution to the oceanic biological carbon pump through the production and export of organic carbon. However, there is little consensus as to the main drivers of spring bloom formation, exacerbated by a lack of in situ observations of the phytoplankton community composition and its evolution during this critical period. We investigated the dynamics of the phytoplankton community structure at two contrasting sites in the Iceland and Norwegian basins during the early stage (25 March–25 April) of the 2012 North Atlantic spring bloom. The plankton composition and characteristics of the initial stages of the bloom were markedly different between the two basins. The Iceland Basin (ICB) appeared well mixed down to >400 m, yet surface chlorophyll a (0.27–2.2 mg m−3) and primary production (0.06–0.66 mmol C m−3 d−1) were elevated in the upper 100 m. Although the Norwegian Basin (NWB) had a persistently shallower mixed layer (<100 m), chlorophyll a (0.58–0.93 mg m−3) and primary production (0.08–0.15 mmol C m−3 d−1) remained lower than in the ICB, with picoplankton (<2 μm) dominating chlorophyll a biomass. The ICB phytoplankton composition appeared primarily driven by the physicochemical environment, with periodic events of increased mixing restricting further increases in biomass. In contrast, the NWB phytoplankton community was potentially limited by physicochemical and/or biological factors such as grazing. Diatoms dominated the ICB, with the genus Chaetoceros (1–166 cells mL−1) being succeeded by Pseudo-nitzschia (0.2–210 cells mL−1). However, large diatoms (>10 μm) were virtually absent (<0.5 cells mL−1) from the NWB, with only small nano-sized (<5 μm) diatoms (i.e. Minidiscus spp.) present (101–600 cells mL−1). We suggest microzooplankton grazing, potentially coupled with the lack of a seed population of bloom-forming diatoms, was restricting diatom growth in the NWB, and that large diatoms may be absent in NWB spring blooms. Despite both phytoplankton communities being in the early stages of bloom formation, different physicochemical and biological factors controlled bloom formation at the two sites. If these differences in phytoplankton composition persist, the subsequent spring blooms are likely to be significantly different in terms of biogeochemistry and trophic interactions throughout the growth season, with important implications for carbon cycling and organic matter export.


2018 ◽  
Vol 9 (4) ◽  
pp. 185-190
Author(s):  
Thi Thu Huong Tran ◽  
Thi Thuy Duong ◽  
Trung Kien Nguyen ◽  
Thi Phuong Quynh Le ◽  
Duc Dien Nguyen ◽  
...  

This study aims to investigate the potential effects of environmental variables and the toxicity of nanosilver colloids synthesized by chemical reduction method on growth and development of phytoplankton community (the Microcystis genus dominance) in the eutrophication Tien lake water, Hanoi city, Vietnam. The variables analyzed including: physical (pH and Turbidity), chemical (content of NH4+, PO43- and silver metal), biological (content of Chlorophyll-a, cell density). The characteristic of nanomaterial was confirmed by using UV-visible spectrophotometer, TEM and HR-TEM methods. The obtained silver nanoparticles (AgNPs) showed that their spherical form and uniform size varied from 10 to 15 nm. The experimental results showed that the samples treated with AgNPs inhibition on growth against M. aeruginosa at concentration 1 mg/l after 8 days. The content of silver in aquarium water decreased from 1 mg/l (D0) to 0.8 mg/l (D8). The contents of chlorophyll-a of phytoplankton community, including Microcystis genus in samples exposed with AgNPs were declined from 11.27 ± 0.56g/L (D0) to 1.98 ± 0.37 g/L (D8) . The environmental variables such as: pH, temperature, dissolved oxygen, turbidity, ammonium, phosphate... in the experiment were below the limit of the Vietnam Standard 08:2015/MONRE for surface water quality. Mục đích của nghiên cứu này là khảo sát ảnh hưởng của vật liệu nano bạc tổng hợp bằng phương pháp khử hóa học đến sinh trưởng và phát triển của quần xã thực vật nổi (chủ yếu là chi Microcystis) trong nước hồ Tiền phú dưỡng, tại Hà Nội, Việt Nam. Các thông số phân tích bao gồm: thủy lý (pH và độ đục), hóa học (hàm lượng amoni, photphat và hàm lượng bạc kim loại), sinh học (hàm lượng chất diệp lục, mật độ tế bào). Đặc trưng của vật liệu được xác định bằng các phương pháp quang phổ UV-VIS, TEM và HR-TEM. Vật liệu nano bạc có dạng hình cầu, kích thước đồng nhất trong khoảng 10-15nm. Kết quả thử nghiệm sau 8 ngày cho thấy các mẫu có bổ sung vật liệu nano bạc ức chế sinh trưởng đối với vi khuẩn lam M. aeruginosa ở nồng độ 1mg/l. Hàm lượng bạc kim loại giảm từ 1 mg/l (ngày đầu tiên) xuống còn 0.8 mg/l (vào ngày cuối cùng). Sinh khối thực vật nổi trong đó có chi Microcystis trong mẫu xử lý với AgNPs đã giảm tương ứng từ 11.27 ± 0.56 g/L (ngày đầu tiên, D0) xuống 1.98 ± 0.37 g/L (ngày cuối cùng, D8). Các thông số môi trường của nước hồ đều nằm dưới giới hạn cho phép của QCVN 08:2015/BTNMT đối với chất lượng nước mặt.


2015 ◽  
Vol 12 (1) ◽  
pp. 93-133 ◽  
Author(s):  
C. J. Daniels ◽  
A. J. Poulton ◽  
M. Esposito ◽  
M. L. Paulsen ◽  
R. Bellerby ◽  
...  

Abstract. The spring bloom is a key annual event in the phenology of pelagic ecosystems, making a major contribution to the oceanic biological carbon pump through the production and export of organic carbon. However, there is little consensus as to the main drivers of spring bloom formation, exacerbated by a lack of in situ observations of the phytoplankton community composition and its evolution during this critical period. We investigated the dynamics of the phytoplankton community structure at two contrasting sites in the Iceland and Norwegian Basins during the early stage (25 March–25 April) of the 2012 North Atlantic spring bloom. The plankton composition and characteristics of the initial stages of the bloom were markedly different between the two basins. The Iceland Basin (ICB) appeared well mixed to > 400 m, yet surface chlorophyll a (0.27–2.2 mg m–3) and primary production (0.06–0.66 mmol C m–3 d–1) were elevated in the upper 100 m. Although the Norwegian Basin (NWB) had a persistently shallower mixed layer (< 100 m), chlorophyll a (0.58–0.93 mg m–3) and primary production (0.08–0.15 mmol C m–3 d–1) remained lower than in the ICB, with picoplankton (> 2 μm) dominating chlorophyll a biomass. The ICB phytoplankton composition appeared primarily driven by the physicochemical environment, with periodic events of increased mixing restricting further increases in biomass. In contrast, the NWB phytoplankton community was potentially limited by physicochemical and/or biological factors such as grazing. Diatoms dominated the ICB, with the genus Chaetoceros (1–166 cells mL–1) being succeeded by Pseudo-nitzschia (0.2–210 cells mL–1). However, large diatoms (> 10 μm) were virtually absent (< 0.5 cells mL–1) from the NWB, with only small nanno-sized (< 5 μm) diatoms present (101–600 cells mL–1). We suggest micro-zooplankton grazing, potentially coupled with the lack of a seed population of bloom forming diatoms, was restricting diatom growth in the NWB, and that large diatoms may be absent in NWB spring blooms. Despite both phytoplankton communities being in the early stages of bloom formation, different physicochemical and biological factors controlled bloom formation at the two sites. If these differences in phytoplankton composition persist, the subsequent spring blooms are likely to be significantly different in terms of biogeochemistry and trophic interactions throughout the growth season, with important implications for carbon cycling and organic matter export.


2020 ◽  
Vol 32 ◽  
Author(s):  
Eucilene Alves Santana ◽  
Edson Fontes de Oliveira ◽  
Nataluzo da Silva Balbino ◽  
Helen Gurgel

Abstract: Sustainable Use Units have been carrying out sustainable management since the 1990s in the State of Amazonas, leading to research on the influence of management plans on restoring ecosystems. We developed an integrative review and analyzed official documents, data from the Brazilian government and information obtained from fishermen on the Unini River Extractive Reserve. The review articles were analyzed qualitatively, and a X2 test was used to verify differences in the distribution of proportions of pirarucu between the years after implementing the management. The management plan was the most cited as a solution to the environmental, social, and economic problems identified in the ecosystems. The data showed an increase in the numbers of pirarucu both in State of Amazonas and in the Unini River Reserve, reinforcing the perception of the community and fishermen. This suggests that when management plans are developed with the involvement of the local community, they present potential to restore ecosystems.


2021 ◽  
Author(s):  
Laurentia Ungureanu ◽  
◽  
Daria Tumanova ◽  
Grigore Ungureanu ◽  
◽  
...  

The article presents the results of study of qualitative and quantitative indicators of phytoplankton of the Dniester River within the Republic of Moldova and Dubasari reservoir in 2020. In phytoplankton compositions of the Dniester River were identified 64 species, Dubasari Lake – 56 species. The numbers of phytoplankton changed within the limits 0,39 to 16,99 mln. cel/l with biomass 0,7-17,19 g/m3 in Dniester River and in Dubasari Lake – 3,47-14,83 mln. cel/l with biomass 4,76-11,29 g/m3. The values of saprobic indexes, estimated on the basis of species-indicators from phytoplankton composition, which are in proportion of 60% typically β-mezosaprobic, confirm the following: the water quality of Dniester River and Dubasari Lake in the period of 2020 year was satisfactory for the development of phytoplankton and was attributed mainly to II-III (good-moderately polluted) quality classes.


2001 ◽  
Vol 58 (7) ◽  
pp. 1371-1379 ◽  
Author(s):  
Beatrix E Beisner

Phytoplankton communities in lakes are exposed to different within-season frequencies of heterogeneity in resource supply because of wind-induced vertical mixing. Effects of such heterogeneity, in conjunction with herbivory, on phytoplankton community structure have rarely been simultaneously examined, despite the fact that each factor can have large effects on phytoplankton composition and diversity. This study uses replicated oligotrophic mesocosms to examine the effects of herbivory and different scales of temporal heterogeneity in deepwater mixing. The pattern of vertical mixing alone had minor effects on phytoplankton community diversity and composition. The herbivore Daphnia caused a shift in phytoplankton composition to less edible types, based mainly on morphological features (spiny shapes and trichomes on cell walls) rather than size structure alone. Phytoplankton richness depended jointly on mixing frequency and large Daphnia biomasses. When systems were well mixed, with high encounter rates between predator and prey populations, phytoplankton community richness was lowest. By contrast, the systems that were least often mixed had highest richness. These results are related to limited encounter rates with infrequent mixing and to the availability of refuges from predation. Responses to different scales of temporal heterogeneity in these oligotrophic phytoplankton communities depend more on Daphnia feeding than on resource pulsing.


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