scholarly journals Spatial and temporal variation of the phytoplankton structure in cascading oligotrophic reservoirs of southeast Brazil

2020 ◽  
Vol 32 ◽  
Author(s):  
Ana Margarita Loaiza-Restano ◽  
Gisele Carolina Marquardt ◽  
Carla Ferragut ◽  
Carlos Eduardo de Mattos Bicudo
Keyword(s):  
Species Composition ◽  
Phytoplankton Biomass ◽  
Structural Changes ◽  
Longitudinal Profile ◽  
Spatial And Temporal Variation ◽  
Austral Winter ◽  
Phytoplankton Structure ◽  
Cascade Effect ◽  
Key Factor ◽  
Cascading Reservoirs

Abstract: Aim Structural changes in phytoplankton was evaluated in one ultraoligotrophic and two oligotrophic cascading reservoirs during two climatic periods (austral winter and summer) of 2014. Changes in phytoplankton biomass, species composition, and codons (functional groups) were evaluated along a vertical and a longitudinal profile. Methods Four sampling sites were selected for the first reservoir in the cascade (Cachoeira do França) and three for each of the other two reservoirs (Cachoeira da Fumaça and Serraria). Samples were collected along a vertical and a longitudinal profile. Species biomass and codons ‘sensu’ Reynolds were identified and expressed in terms of biomass. Results 18 codons were identified and associated to the reservoirs’ limnological conditions. Composition and biomass of descriptor species changed among seasons. Codon B consisting mainly of Discostella stelligera was the most frequent in all reservoirs in both climatic seasons. Conclusions Our findings showed that seasonality was the key factor for the species composition and phytoplankton codons changes. However, the cascade effect on phytoplankton structure was shown by the continuous contribution of Ceratium furcoides (codon LM) during the winter, and of Discostella stelligera (codon B) in both sampling periods in all three reservoirs.

Effect of Water Body Morphology on Phytoplankton Biomass and Species Composition

2013 ◽  
Vol 777 ◽  
pp. 375-379
Author(s):  
Yue Hong Zhang ◽  
Fei Peng Li ◽  
Hu Hu Zhao ◽  
Hai Ping Zhang
Keyword(s):  
Species Composition ◽  
Water Body ◽  
Environmental Variables ◽  
Phytoplankton Biomass ◽  
Population Variation ◽  
Nutrient Concentrations ◽  
Body Morphology ◽  
Key Factor ◽  
Lake Type ◽  
River Type

Environmental variables, phytoplankton biomass and species composition in Nanhu Lake in Yingdong Village, Chongming Island were monitored from August 2010 to September 2011. The relationship between environmental variables and population variation of phytoplankton was discussed. The results showed that water body morphology was the key factor leading to the variation of phytoplankton community. In river-type waters the level of phytoplankton biomass was generally higher than that in lake-type waters, especially in summer. During the period of seasonal change, in river-type waters Cyanophyta dominated longer with the succession from Cyanophyta to Chlorophyta and Bacillariophyta occurred later than that in lake-type waters. Redundancy analysis (RDA) indicated that the morphology of enclosed waters had influence on phytoplankton biomass and species composition. One of the mechanisms may be that water body morphology could have impact on the growth and species dynamics of phytoplankton indirectly by affecting nutrient concentrations.

The effect of cyanobacterial blooms in the Siemianówka Dam Reservoir on the phytoplankton structure in the Narew River

2011 ◽  
Vol 40 (1) ◽  
Author(s):  
Magdalena Grabowska ◽  
Hanna Mazur-Marzec
Keyword(s):  
Chemical Analysis ◽  
Species Composition ◽  
Phytoplankton Biomass ◽  
Cyanobacterial Blooms ◽  
Dam Reservoir ◽  
Long Distance ◽  
Toxic Cyanobacteria ◽  
Phytoplankton Structure ◽  
North Eastern ◽  
Lowland Reservoir

AbstractThe effect of cyanobacterial blooms on the phytoplankton structure in the lowland Narew River (north-eastern Poland) was examined. The studies were carried out at stations situated at different distances from the eutrophic Siemianówka Dam Reservoir. In 2008, the investigated lowland reservoir and the outflowing river were characterized by the dominance of toxic cyanobacteria (from July to October). At a station situated 130 km below the dam, species composition in the river was very similar to that in the shallow reservoir. Planktothrix agardhii was the main and permanent dominant, both in limnoplankton and potamoplankton. The current study indicates that the eutrophic Siemianówka Dam Reservoir is the main and rich source of phytoplankton for the outflowing Narew River. Cyanobacteria were dominant in the river phytoplankton at all sampling stations, but their share in phytoplankton biomass gradually decreased with the distance from the dam. Chemical analysis revealed the presence of microcystins (MCs) in water samples collected from June to October. The toxins, mainly demethylated MC analogues, were detected at a long distance down the river, even 100 km from the dam. Maximum concentration of MCs (14.3 μg l−1) was measured on 13 October, 9.1 km below the dam.

scholarly journals Diversity of Algae and Cyanobacteria and Bioindication Characteristics of the Alpine Lake Nesamovyte (Eastern Carpathians, Ukraine) from 100 Years Ago to the Present

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 256
Author(s):  
Petro M. Tsarenko ◽  
Olena P. Bilous ◽  
Olha M. Kryvosheia-Zakharova ◽  
Halyna H. Lilitska ◽  
Sophia Barinova
Keyword(s):  
Species Composition ◽  
Structural Changes ◽  
Algal Species ◽  
Taxonomic Composition ◽  
Alpine Lake ◽  
Algal Flora ◽  
Ecological Analysis ◽  
Modern Species ◽  
Eastern Carpathians ◽  
Infraspecific Taxa

The species diversity and changes in the structural dynamics of the algal flora from the alpine lake Nesamovyte has been studied for 100 years. During the period of investigations, 234 species (245 infraspecific taxa) were revealed to cover more than 70% of the modern species composition of the studied lake. The modern biodiversity of algae is characterized by an increase in the number of widespread forms, a change from the baseline “montane” complex in comparison to the beginning of the 20th century. Nevertheless, the Nesamovyte Lake still has a unique algae composition that is typical for high-mountainous European lakes. The presence of a different complex of conventionally arctic species of algae, in particular, diatoms is discussed. Structural changes in the taxonomic composition of the algal flora of the lake as well as in the complex of the leading genera, species and their diversity are revealed. An ecological analysis of the algal species composition of the lake showed vulnerability and degradation to the ecosystem of the lake. On this basis, the issue regarding the question of protection and preservation of the algae significance and uniqueness of the flora of algae in the Nesamovyte Lake are discussed.

Development of Forest Shelterbelts Considering Statistical Forecasts Modelling of Local Weather

2021 ◽  
Vol 18 (1) ◽  
pp. 7-14
Author(s):  
Irina Volkova ◽  
Kseniia Pitulko ◽  
Anzhelika Sergeeva ◽  
Saida Pshidatok
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Structural Changes ◽  
Moscow Oblast ◽  
Phytopathogenic Bacteria ◽  
Heat Damage ◽  
Class 1 ◽  
Local Weather ◽  
Species Class

This work aims to study the effect of high temperatures and phytopathogenic bacteria on different types of trees in the forest shelterbelts. Therefore, in 2018, 17 tree species were studied from 50 sample sites in the Moscow oblast (Russia). Leaf scorching, diseases caused by phytopathogenic bacteria, and heat damage to the crowns were examined in 5224 tree species. Based on the degree of crown damage, the studied tree species were divided into four classes. It was found that the heat damage to tree crowns was identical between the three sampling aspects (correlation coefficient 0.99). The plant species composition must be considered when developing forest shelterbelts. A long-term forecast on structural changes of planted areas is possible, considering the species composition and climatic characteristics of the region. Class 5 includes only chestnut; class 4 includes three species; class 3 is represented by seven species. Class 2, includes six species, and is the most suitable in developing forest plantations. No tree species in class 1 were found (trees with no damage). There is a connection between pathologies and heat injuries in trees from classes 4 to 5 (correlation 0.89).

Experimental culling of minnows suppresses cyanobacterial bloom under low-nutrient conditions

2019 ◽  
Vol 76 (11) ◽  
pp. 2102-2109 ◽  
Author(s):  
Blake R. Stuparyk ◽  
Mark Graham ◽  
Jenna Cook ◽  
Mitchell A. Johnsen ◽  
Karen K. Christensen-Dalsgaard ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Trophic Cascade ◽  
Phytoplankton Biomass ◽  
Management Practices ◽  
Phytoplankton Community ◽  
Cyanobacterial Bloom ◽  
Nutrient Status ◽  
Cyanobacterial Blooms ◽  
Phytoplankton Blooms ◽  
Cascade Effect

Cyanobacterial blooms in lakes of low nutrient status are recent ecological surprises. Culling of planktivorous fish may help suppress phytoplankton blooms via a trophic cascade effect. To test this hypothesis, we conducted a 90-day experiment adjacent to a shallow oligomesotrophic lake increasingly beset by midsummer cyanobacterial blooms in the presence of high abundances of minnows and sparse herbivorous zooplankton. The single-factor (± three spottail shiners, Notropis hudsonius) experimental design was replicated 10 times for a total of twenty 1200 L capacity mesocosms. Contrary to the trophic cascade hypothesis, minnow removal decreased the abundance of bosminids capable of grazing cyanobacteria. Nevertheless, removal of the minnows significantly both suppressed phytoplankton biomass and offset the development of cyanobacteria, such as Gloeotrichia echinulata. Lower concentrations of phosphorus and nitrogen in the fishless relative to stocked mesocosms best explained these differences in the phytoplankton community. Our findings highlight how fisheries management practices that enhance minnow populations in lakes of low productivity may inadvertently contribute to cyanobacterial blooms through increased nutrient cycling.

scholarly journals Monitoring Post-Fire Recovery of Chaparral and Conifer Species Using Field Surveys and Landsat Time Series

2019 ◽  
Vol 11 (24) ◽  
pp. 2963
Author(s):  
Christopher L. Kibler ◽  
Anne-Marie L. Parkinson ◽  
Seth H. Peterson ◽  
Dar A. Roberts ◽  
Carla M. D’Antonio ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Land Cover ◽  
Species Composition ◽  
Vegetation Cover ◽  
Spatial And Temporal Variation ◽  
Conifer Species ◽  
Burn Scar ◽  
Green Vegetation ◽  
Normalized Burn Ratio

Recovery trajectories derived from remote sensing data are widely used to monitor ecosystem recovery after disturbance events, but these trajectories are often retrieved without a precise understanding of the land cover within a scene. As a result, the sources of variability in post-disturbance recovery trajectories are poorly understood. In this study, we monitored the recovery of chaparral and conifer species following the 2007 Zaca Fire, which burned 97,270 ha in Santa Barbara County, California. We combined field survey data with two time series remote sensing products: the relative delta normalized burn ratio (RdNBR) and green vegetation (GV) fractions derived from spectral mixture analysis. Recovery trajectories were retrieved for stands dominated by six different chaparral species. We also retrieved recovery trajectories for stands of mixed conifer forest. We found that the two remote sensing products were equally effective at mapping vegetation cover across the burn scar. The GV fractions (r(78) = 0.552, p < 0.001) and normalized burn ratio (r(78) = 0.555, p < 0.001) had nearly identical correlations with ground reference data of green vegetation cover. Recovery of the chaparral species was substantially affected by the 2011–2017 California drought. GV fractions for the chaparral species generally declined between 2011 and 2016. Physiological responses to fire and drought were important sources of variability between the species. The conifer stands did not exhibit a drought signal that was directly correlated with annual precipitation, but the drought likely delayed the return to pre-fire conditions. As of 2018, 545 of the 756 conifer stands had not recovered to their pre-fire GV fractions. Spatial and temporal variation in species composition were important sources of spectral variability in the chaparral and conifer stands. The chaparral stands in particular had highly heterogeneous species composition. Dominant species accounted for between 30% and 53% of the land cover in the surveyed chaparral patches, so non-dominant land cover types strongly influenced remote sensing signals. Our study reveals that prolonged drought can delay or alter the post-fire recovery of Mediterranean ecosystems. It is also the first study to critically examine how fine-scale variability in land cover affects time series remote sensing analyses.

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