scholarly journals Phytoplankton functional groups in a tropical reservoir in the Brazilian semiarid region

2017 ◽  
Vol 65 (3) ◽  
pp. 1129
Author(s):  
Ruceline Paiva Melo Lins ◽  
Beatriz Susana Ovruski de Ceballos ◽  
Luiz Carlos Serramo Lopez ◽  
Luciana Gomes Barbosa
Keyword(s):  
Functional Groups ◽  
Environmental Conditions ◽  
Phytoplankton Biomass ◽  
Fish Farming ◽  
Semiarid Region ◽  
Monthly Basis ◽  
Brazilian Semiarid ◽  
Phytoplankton Functional Groups ◽  
Abiotic Variables ◽  
Density And Biomass

Phytoplankton functional groups structure and species abundance vary according to environmental conditions. The present study investigated the natural and anthropogenic stressors that affect phytoplankton functional group biomass in a Brazilian semiarid region reservoir (Argemiro de Figueiredo reservoir). Sampling occurred between August 2007 and July 2009 on a bi-monthly basis for the first year, and in a monthly basis for the last two years. There were three collection points (PC: river confluence; PNC: near the cages; PD: dam site). The water environment analysis of abiotic variables included: temperature, transparency, coefficient of vertical light attenuation, dissolved oxygen, pH, electrical conductivity, alkalinity, dissolved inorganic nitrogen, and reactive soluble phosphorus. Phytoplankton samples were collected into a Van Dorn bottle, and were then preserved in acetic lugol and were quantified using an inverted microscope to determine phytoplankton density and biomass; the identified species were assembled in functional groups. The data were explored by canonical correspondence analysis. Individual analyses were made to test the temporal and spatial variability of the data and the factors that interfered most with the biotic and abiotic variables. Functional groups S1, SN, and K, consisting of filamentous Planktothrix agardhii (Gomont) Anagnostidis & Komárek, Cylindrospermopsis raciborskii (Woloszynska) Seenaya & Subba Raju, and the coccoid Aphanocapsa incerta (Lemmermann) Cronberg & Komárek, respectively, dominated the dry months when the water was warm, turbid, and alkaline. The overflow reservoir served as a natural disturbance reducing the phytoplankton biomass to less than 50 % and the dominance of cyanobacteria, promoting the domain of functional groups F, M, MP, Lo, and X2. The nutrient inputs from intensive fish farming, associated with a low local depth (Zmax = 7.7 m) close to the cages (PNC), resulted in a significant human disturbance that increased the prevalence of functional groups S1, SN, and K, which are composed primarily of cyanobacteria. We concluded that, in reservoirs, overflow events are natural disturbances that have the ability to reduce phytoplankton biomass and alter the structure of local communities, and that intensive fish farming is an anthropogenic disturbance that increases the availability of nutrients and stimulates an increase in biomass of the functional groups that include cyanobacteria. Furthermore, the functional groups of phytoplankton were reliable control of environmental conditions in the reservoirs of tropical semiarid regions.

scholarly journals Phytoplankton functional groups in shallow aquatic ecosystems from the semiarid region of Brazil

2021 ◽  
Vol 33 ◽  
Author(s):  
Klivia Rilavia Paiva da Silva ◽  
José Etham de Lucena Barbosa ◽  
Lucineide Maria Santana ◽  
Luciana Gomes Barbosa
Keyword(s):  
Functional Groups ◽  
Aquatic Ecosystems ◽  
Abiotic Factors ◽  
Ecological Status ◽  
Semiarid Region ◽  
Control Mechanisms ◽  
Phytoplankton Composition ◽  
Brazilian Semiarid ◽  
Phytoplankton Functional Groups ◽  
Q Index

Abstract: Aim The study analyzed the potential use of the phytoplankton functional groups as an environmental bioindicator in aquatic ecosystems of Brazilian semiarid region. Methods Using data collected over five years of a natural lagoon and two reservoirs, we evaluate the relationship between functional groups and environmental conditions through the multivariate approach. The Q index was applied to assess ecological status in these ecosystems. Results In Panati, the temporary and natural lagoon, the partial habitat desiccation and presence of macrophytes reflected in the less nutrients concentrations and phytoplankton composition, with high biomass of coccoids Chlorophyceae, diatoms and desmids (functional groups J, MP and N, respectively). Taperoá and Soledade reservoirs presented high cyanobacteria contribution, however the biomass and contribution of cyanobacteria in Taperoá (SN, S1) were lower than in Soledade. In this reservoir, cyanobacteria were more abundant, alternating in dominance (LO, M, LM, SN, S1). According to tendencies revealed by Redundancy Analysis (RDA), the main driving abiotic factors on the phytoplankton functional groups were pH, nutrients and light availability. As expected, phytoplankton composition directly influenced the Q index result, showing mostly bad to tolerable conditions in Soledade, medium to good in Taperoá and good to excellent in Panati. Conclusions The Q index was a good tool to assess the water quality and ecological status in aquatic ecosystems from the Brazilian semiarid region, reflecting the influence of natural control mechanisms on the harmful cyanobacteria blooms in temporary ecosystems.

scholarly journals Driving forces of the diel distribution of phytoplankton functional groups in a shallow tropical lake (Lake Monte Alegre, Southeast Brazil)

2009 ◽  
Vol 69 (1) ◽  
pp. 75-85 ◽  
Author(s):  
LM. Rangel ◽  
LHS. Silva ◽  
MS. Arcifa ◽  
A. Perticarrari
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Rainy Season ◽  
Phytoplankton Biomass ◽  
Driving Forces ◽  
Circulation Pattern ◽  
Dry Period ◽  
Phytoplankton Functional Groups ◽  
The Vertical Distribution ◽  
Cool Dry Season

Phytoplankton vertical and diel dynamics in a small shallow lake (Lake Monte Alegre, Ribeirão Preto, state of São Paulo) were investigated in two climatological periods: July 2001 (cool-dry season) and March 2002 (warm-rainy season). Monte Alegre is a eutrophic reservoir, with a warm polymictic discontinuous circulation pattern. The lake was thermally stratified in both periods, although dissolved oxygen varied less in the cool-dry period. Phytoplankton biomass was higher in the warm-rainy season and the vertical distribution was stratified in both seasons. Flagellate groups (Lm, Y, W1 and W2) and functional groups typical of shallow eutrophic environments (J, X1 and Sn) were important throughout the study period. The lake's thermal pattern strongly influenced the vertical distribution of the phytoplankton community in both periods. Biomass, functional groups and size classes of phytoplankton also were determined by the presence of more efficient herbivores in the lake, especially during the cool-dry period when phytoplankton biomass decreased.

Bottom-up and top-down effects on phytoplankton functional groups in Hulun Lake, China

2021 ◽  
Vol 57 ◽  
pp. 3
Author(s):  
Chengxue Ma ◽  
Chang Zhao ◽  
Patteson Chula Mwagona ◽  
Ziyu Li ◽  
Zixuan Liu ◽  
...  
Keyword(s):  
Functional Groups ◽  
Phytoplankton Biomass ◽  
Eutrophic Lake ◽  
Positive Influence ◽  
Freshwater Ecosystems ◽  
Top Down ◽  
Bottom Up ◽  
Physical Chemical ◽  
Phytoplankton Functional Groups ◽  
Negative Effect

The debates about the extent to which phytoplankton in freshwater ecosystems are regulated by top-down or bottom-up forces have been ongoing for decades. This study examines the effects of bottom-up and top-down factors on the phytoplankton functional groups in a eutrophic lake. Phytoplankton and zooplankton were sampled and physical-chemical variables measured from May 2019 to October 2019 in Lake Hulun, China. Approximately 43 phytoplankton species were observed and grouped into 23 functional groups. For the zooplankton, about 27 species were observed and classified into 8 functional groups. The study revealed that the bottom-up effects of physical-chemical variables on some phytoplankton functional groups was stronger than the top-down effects of zooplankton. Water temperature (WT), total phosphorus (TP), total nitrogen (TN), conductivity (Cond), water transparency (SD), and dissolved oxygen (DO) significant influence the biomass of the phytoplankton functional groups. The biomass of phytoplankton functional groups was influenced positively by nutrient availability likely because nutrients influence the growth and reproduction of phytoplankton in freshwater. WT and DO had a positive influence on biomass of phytoplankton functional groups. Conversely, phytoplankton biomass revealed a decreasing trend when SD and Cond significantly increased. This study showed that zooplankton functional groups were positively correlated with phytoplankton biomass implying that the top-down control of phytoplankton by the zooplankton in the lake is not strong enough to produce a negative effect. It is evident that the zooplankton functional groups in Lake Hulun are controlled more by bottom-up force than top-down.

scholarly journals Hydrothermal treatments for overcoming dormancy in seeds of Mimosa ophthalmocentra Mart. ex Benth. (Fabaceae: Mimosoideae)

2017 ◽  
Vol 4 (7) ◽  
pp. 103-111
Author(s):  
Azenate Campos Gomes ◽  
Alecksandra Vieira de Lacerda ◽  
Riselane Lucena de Alcântara Bruno ◽  
Edna Ursulino Alves ◽  
Carina Seixas Maia Dornelas ◽  
...  
Keyword(s):  
Experimental Design ◽  
Water Temperature ◽  
Analysis Of Variance ◽  
Seed Dormancy ◽  
Environmental Conditions ◽  
Dry Mass ◽  
Semiarid Region ◽  
Tukey Test ◽  
Brazilian Semiarid ◽  
Emergence Percentage

The efficiency in the production of seedlings is decisive for the final result of their applicability. Therefore, strategies to ensure a rapid and uniform emergence are necessary, especially when it is associated with sustainable methods. The aim of this study was to evaluate the influence of different water temperatures as overcoming seed dormancy in Mimosa ophthalmocentra Mart. ex Benth., simply and economically, in the Brazilian Semiarid Region. The experimental design was completely randomized with four replications, each one consisting of 50 seeds, which were subjected to six treatments: intact seeds (T1/control) and seeds immersed in water at 55, 65, 75, 85, and 95 °C (T2, T3, T4, T5, and T6, respectively). Sowing was performed in trays under environmental conditions and evaluations were performed daily for 28 days. The emergence percentage, emergence speed index (ESI), and length and dry mass of seedlings were evaluated. Data were subjected to analysis of variance, and the means were compared by Tukey test (p < 0.05). M. ophthalmocentra has tegumentary dormancy, and its emergence was influenced by water temperature. Immersion of seeds in water at 75 ºC for 1 min provided the best result with 60% of emergence, ESI of 2.68, and seedlings with longer lengths and higher dry mass.

scholarly journals Phytoplankton functional groups indicators of environmental conditions in floodplain rivers and lakes of the Paraná Basin

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Barbara Furrigo Zanco ◽  
Alfonso Pineda ◽  
Jascieli Carla Bortolini ◽  
Susicley Jati ◽  
Luzia Cleide Rodrigues
Keyword(s):  
Environmental Factors ◽  
Functional Groups ◽  
Environmental Conditions ◽  
Trophic State ◽  
Phytoplankton Community ◽  
Paraná River ◽  
Parana River ◽  
Phytoplankton Functional Groups ◽  
Rivers And Lakes ◽  
Floodplain Rivers

Abstract Aim: The objective of this study was to evaluate the efficacy of phytoplankton functional groups as indicators of environmental conditions in floodplain rivers and lakes with different trophic state and connectivity degree to the Paraná River. Phytoplankton functional groups (FGs) cluster sensitive species to environmental variation and can be an alternative for environmental monitoring. Methods Samples were performed quarterly from 2010 to 2013 in the Ivinhema, Paraná and Baia Rivers and in three lakes permanently connected to each river. Results 419 taxa were identified, and those taxa that had values greater than 5% of the total biovolume were classified into FGs (P, C, A, B, MP, H1, W1, J, TD, LO, and N). The lakes presented higher biovolume and were more productive than rivers, especially in the dry periods. The rivers presented light limitation and low phytoplankton development. The FG LO was an indicator in rainy seasons. Both rivers and lakes were mostly oligotrophic. We registered FG indicators only for the lakes (A, B, C, E, LO, P, and W1) and mesotrophic environments (A, B, C, E, J, LO, and P). Conclusion The FGs reflected the seasonal variation and the trophic state of environments in the upper Paraná River floodplain, mainly in the lentic environments. The species-environment relationship (FGs as indicators) was clearer in the lakes, probably because of the longer water retention that allows evidencing the response of the phytoplankton community to environmental factors. On the other hand, the absence of FGs as indicators in the rivers could be due to the high water flow that promotes dispersal stochasticity and masks the relationship between the environmental factors and the phytoplankton community. Thus, phytoplankton FGs proved to be a viable tool to evaluate the environmental conditions in a floodplain.

scholarly journals Spatial-temporal evaluation of water quality in Brazilian semiarid reservoirs

2020 ◽  
Vol 15 (1) ◽  
pp. 92-104
Author(s):  
Karina Waleska Lopes Rossiter ◽  
Erika Alves Tavares Marques ◽  
Cláudia Ricardo de Oliveira ◽  
Elena Matta ◽  
Maria Manuela Queiroz Martins Mantero Morais
Keyword(s):  
Water Quality ◽  
Principal Component ◽  
Fish Farming ◽  
Quality Characteristics ◽  
Irrigated Agriculture ◽  
Semiarid Region ◽  
Dry Period ◽  
Brazilian Semiarid ◽  
Increasing Demand ◽  
Water Uses

Abstract Reservoirs are used in the Brazilian semiarid for human supply, power generation, irrigated agriculture and more recently, intensive fish farming, the Sobradinho reservoir being the largest of this region. In the last decade, the semiarid region has suffered a strong drought, in opposite direction to the increasing demand of multiple water uses. The present work aims to study the spatial-temporal variation of water quality in two reservoirs in the Brazilian semiarid region (Sobradinho and Itaparica reservoirs). For this, samples were collected in the dry and wet periods between 2011 and 2014, and the results were analyzed through boxplot charts and Principal Component Analysis (PCA). For both reservoirs, our results showed that the PCAs did not evidence a specific seasonal change in the water quality characteristics, distinguishing the wet and dry periods through the four years studied. A clear temporal pattern was detected in both reservoirs, with higher values of turbidity, dissolved oxygen and total phosphorus in the wet period and higher values of pH and alkalinity in the dry period. An upstream reduction of nutrients and turbidity was not found in this study, as is reported in literature for consecutive reservoirs, probably due to the irrigation and aquaculture activities, mainly in Itaparica reservoir.

scholarly journals Responses of phytoplankton functional groups to environmental factors in the Maixi River, southwest China

2017 ◽  
Author(s):  
Guojia Huang ◽  
Qiuhua Li ◽  
Xiaoqing Wang ◽  
Mengshu Han ◽  
Lei Li ◽  
...  
Keyword(s):  
Steady State ◽  
Phase I ◽  
Functional Groups ◽  
Phase Ii ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Early Summer ◽  
Late Spring ◽  
Total Biomass ◽  
Phytoplankton Functional Groups

<p>The functional groups approach is an efficient way to analyze seasonal changes in phytoplankton biomass as it is based on the physiological, morphological, and ecological attributes of the species. In this study, we identified the functional groups and driving factors behind short-term succession in phytoplankton communities. We analyzed physical, chemical, and biological factors of the Maixi River in Baihua Reservoir (BHR) from August to September, 2013 (summer, phase I) and March to May, 2014 (late spring and early summer, phase II). The 226 samples collected were divided into 23 functional groups. In phase I, phytoplankton biomass ranged from 4.88 to 30.59 mg·L<sup>-1</sup>, and the group S1 (<em>Pseudanabaena limnetica</em>) had the greatest biomass. In phase II, phytoplankton biomass ranged from 2.22 to 50.61 mg·L<sup>-1</sup>, and groups Y (<em>Cryptomonas</em> sp.) and S1 (<em>P. limnetica</em>) had the greatest biomass. Dominant functional groups in the Maixi River changed from S1 + D + Y + Lo in phase I to Y + S1 in summer. Changes in the phytoplankton community varied between 0 and 0.144 day<sup>-1 </sup>in phase I and between 0.008 and 0.389 day<sup>-1 </sup>in later spring and early summer. This showed a steady-state phytoplankton community during the two phases, in which the functional groups S1 (<em>P. limnetica</em>) and Y (<em>Cryptomonas</em> sp.) were dominant.<em> Pseudanabaena limnetica</em>, <em>Synedra </em>sp., <em>Peridinium </em>sp., and<em> Cryptomonas</em> sp. were dominant during summer, contributing to 70% of the total biomass in the steady-state community, and<em> P. limnetica</em>,<em> Synedra </em>sp., <em>Cryptomonas</em> sp.,<em> </em>and <em>Chlamydomonas</em> sp. were dominant during later spring and early summer, contributing to 60% of the total biomass in the community. Groups S1, D, and Y formed easily in the Maixi River, but <em>P. limnetica</em> was the dominant species in the eutrophic conditions of the Maixi River. According to biotic and abiotic factors, we concluded that the Maixi River is hypertrophic, and water resource management should take blooms of <em>P. limnetica</em> occurring in May into account. Temperature and dissolved oxygen were the critical factors affecting the steady-state of the phytoplankton community in late spring and early summer and summer, respectively. Because the Maixi River is an important source in the BHR, its phytoplankton functional groups directly affect the ecological balance of the water environment.</p>

Nitrogen Stocks in Soil Classes Under Different Land Uses in the Brazilian Semiarid Region

2021 ◽  
Author(s):  
Uemeson José dos Santos ◽  
Everardo Valadares de Sá Barretto Sampaio ◽  
Eunice Maia de Andrade ◽  
Alexandre de Siqueira Pinto ◽  
Bruno de Oliveira Dias ◽  
...  
Keyword(s):  
Semiarid Region ◽  
Land Uses ◽  
Brazilian Semiarid

Management of water supply systems from interbasin transfers: case study in the Brazilian semiarid region

2021 ◽  
pp. 1-12
Author(s):  
José Almir Cirilo ◽  
Alfredo Ribeiro Neto ◽  
Nyadja Menezes Rodrigues Ramos ◽  
Carla Fernanda Fortunato ◽  
Júlia Daniele Silva de Souza ◽  
...  
Keyword(s):  
Water Supply ◽  
Semiarid Region ◽  
Water Supply Systems ◽  
Brazilian Semiarid ◽  
Interbasin Transfers ◽  
Supply Systems
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