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

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.

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Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x2014000400004 ◽

2014 ◽

Vol 26 (4) ◽

pp. 356-366 ◽

Cited By ~ 1

Author(s):

Thársia da Silva Pinto ◽

Vanessa Becker

Keyword(s):

Vertical Distribution ◽

Functional Groups ◽

Northeastern Brazil ◽

Severe Drought ◽

Dry Period ◽

Drought Period ◽

Tropical Water ◽

Phytoplankton Functional Groups ◽

The Vertical Distribution ◽

Dry And Rainy Seasons

AIM: This study analyzed - the diel and vertical dynamics of phytoplankton functional groups in a natural tropical lake (Extremoz Lake, northeast Brazil), to investigate and understand the driver factors of the community during a severe drought period. METHODS: Sampling of the abiotic variables and phytoplankton was performed at intervals of 6 hours over 24 hours in vertical profiles, in dry and rainy seasons (according to the historical average). The phytoplankton species were grouped according to the functional groups' approach sensu Reynolds et al. (2002). RESULTS: October/12 was considered as a dry period (18.4 mm), while March/13, due to the historical average, as a rainy season, due to the low rainfall during the study period (15.7 mm), it was called severe drought. The lake showed thermal and chemical destratification in both periods. Phytoplankton biomass was higher in the dry season and their vertical distribution was stratified in both periods. In both samplings there were less algal biomass during the night. Phytoplankton functional groups of mixed and shallow systems (S1, L0 and K) were descriptors throughout the study period with higher biomass always registered in the group S1, represented by Planktolyngbya limnetica (Cyanobacteria). CONCLUSION: The lack of seasonality observed in this study, due to prolonged drought, may have influenced the pattern of homogeneous behavior in both samplings. This pattern strongly influenced the vertical distribution of phytoplankton in the two periods, with a constancy of dominance of functional descriptors groups.

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Vertical distribution of phytoplankton functional groups in a tropical shallow lake: driving forces on a diel scale

Acta Limnologica Brasiliensia ◽

10.4322/actalb.2011.020 ◽

2011 ◽

Vol 23 (1) ◽

pp. 63-73 ◽

Cited By ~ 8

Author(s):

Luciana Gomes Barbosa ◽

Paulina Maria Maia Barbosa ◽

Francisco Antonio Rodrigues Barbosa

Keyword(s):

Vertical Distribution ◽

Functional Groups ◽

Shallow Lake ◽

Driving Forces ◽

Phytoplankton Functional Groups

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

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2020028 ◽

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.

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

Revista de Biología Tropical ◽

10.15517/rbt.v65i3.29446 ◽

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.

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Assembly history modulates vertical root distribution in a grassland experiment

10.1101/2021.08.24.457510 ◽

2021 ◽

Author(s):

Inés M. Alonso-Crespo ◽

Emanuela W.A. Weidlich ◽

Vicky M. Temperton ◽

Benjamin M. Delory

Keyword(s):

Vertical Distribution ◽

Functional Groups ◽

Plant Communities ◽

Functional Group ◽

Species Level ◽

The Other ◽

Priority Effects ◽

Rooting Depth ◽

Distribution Of Roots ◽

The Vertical Distribution

The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so-called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the mean rooting depth of plant communities was monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefolium and Centaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly than when forbs or legumes were sown first,. In addition, roots moved down the soil profile 24% more slowly in grasses-first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.

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Vertical distribution characteristics of phytoplankton functional groups and their relationships with environmental factors in Lake Basomtso, Tibet, China

Journal of Lake Sciences ◽

10.18307/2021.0114 ◽

2021 ◽

Vol 33 (1) ◽

pp. 86-101

Author(s):

An Ruizhi ◽

◽

Pan Chengmei ◽

Taba Lazhen ◽

Yang Xinlan ◽

...

Keyword(s):

Environmental Factors ◽

Vertical Distribution ◽

Functional Groups ◽

Distribution Characteristics ◽

Phytoplankton Functional Groups

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Vertical distribution and structure of copepod (Arthropoda: Copepoda) assemblages in two different seasons down to 1,200 m in the tropical Southwestern Atlantic

Zoologia (Curitiba) ◽

10.3897/zoologia.35.e13886 ◽

2018 ◽

Vol 35 ◽

pp. 1-11

Author(s):

Cristina de Oliveira Dias ◽

Adriana Valente de Araujo ◽

Sérgio Luiz Costa Bonecker

Keyword(s):

Environmental Factors ◽

Vertical Distribution ◽

Rainy Season ◽

Dry Season ◽

Total Density ◽

Southwestern Atlantic ◽

Southwestern Atlantic Ocean ◽

Different Seasons ◽

Dry Seasons ◽

The Vertical Distribution

The vertical distribution of copepod assemblages, ascertained from the surface down to 1,200 m, was investigated during two sampling periods (rainy and dry seasons), at four depths, in the oligotrophic waters of the southwestern Atlantic Ocean. Total density, diversity, and richness differed among sampling depths. Copepod density decreased with depth in the two sampling periods, with a maximum at 1 m and a slight decrease at 800 m. Higher diversities were observed at 250 m and 1,200 m during the rainy season and at 1 m and 1,200 m during the dry season. The maximum number of species was found at 1,200 m during the rainy season and at 1 m during the dry season. Various copepod assemblages were delimited in the water column in the two sampling periods. The deeper copepod assemblages occupied a wider range of depths. Salinity and temperature influenced the structure of copepod assemblages and reflected the hydrographic characteristics of the water masses in the region. Candaciapachydactyla (Dana, 1849), Scolecithrixdanae (Lubbock, 1856), and Agetuslimbatus (Brady, 1883) were the indicator species found at 1 m. The effects of different environmental factors on the copepod assemblages suggest that these consortia occupy distinct niches in the ocean.

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

Journal of Limnology ◽

10.4081/jlimnol.2017.1613 ◽

2017 ◽

Cited By ~ 1

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

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-1, and the group S1 (Pseudanabaena limnetica) had the greatest biomass. In phase II, phytoplankton biomass ranged from 2.22 to 50.61 mg·L-1, and groups Y (Cryptomonas sp.) and S1 (P. limnetica) 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-1 in phase I and between 0.008 and 0.389 day-1 in later spring and early summer. This showed a steady-state phytoplankton community during the two phases, in which the functional groups S1 (P. limnetica) and Y (Cryptomonas sp.) were dominant. Pseudanabaena limnetica, Synedra sp., Peridinium sp., and Cryptomonas sp. were dominant during summer, contributing to 70% of the total biomass in the steady-state community, and P. limnetica, Synedra sp., Cryptomonas sp., and Chlamydomonas 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 P. limnetica 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 P. limnetica 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.

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