Water level decrease and increased water stability promotes phytoplankton growth in a mesotrophic subtropical lake

Global warming and climate variability can promote changes in freshwater ecosystems that may result in increased frequency of algal blooms. These effects, however, depend strongly on local factors. Peri Lake is a cyanobacteria-dominated shallow lake that has experienced a strong reduction in water level, as well as increased occurrence of algal blooms. The goal of this study was to determine the influence of water level on phytoplankton biomass in Peri Lake. We hypothesise that increased algal blooms are associated with reduction in water level, possibly in response to changes in rainfall patterns. We measured meteorological, physical, and chemical variables over 5 years, as well as chlorophyll-a levels. We observed a strong reduction in total rainfall in the last year of the study, in which the flow of lake water nearly ceased. Phytoplankton biomass increased despite a lack of evidence of water heating or eutrophication. Our results suggest that changes in rainfall regime alter lake characteristics such as retention time and water stability (i.e. increased occurrence of diurnal stratification events), producing favourable conditions for growth of cyanobacterial biomass. These effects perhaps better explain increases in algal biomass in this system than do temperature or nutrient availability alone.

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Is similar the distribution of Chironomidae (Diptera) and Oligochaeta (Annelida, Clitellata) in a river and a lateral fluvial area?

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x1217 ◽

2017 ◽

Vol 29 (0) ◽

Cited By ~ 1

Author(s):

Daniela Aparecida Silveira Cesar ◽

Raoul Henry

Keyword(s):

Water Level ◽

Environmental Changes ◽

River Mouth ◽

Benthic Fauna ◽

Area Reduction ◽

Physical And Chemical Variables ◽

Temporal And Spatial ◽

Study Sites ◽

Physical And Chemical ◽

Lateral Area

Abstract Numerous factors may affect the pattern of distribution of benthic fauna in a river mouth region and, among the macroinvertebrates, Chironomidae and Oligochaeta are the most abundant groups and most tolerant to environmental changes. Aim The aim of this study was to evaluate the controlling factors of and a possible similarity between Chironomidae and Oligochaeta assemblies at two close sites, the mouth of the Guareí River into the Paranapanema River (São Paulo, Brazil) and its lateral fluvial area. Methods Fauna samples were collected every three months during one year. Water physical and chemical variables and sediment variables were also determined in the same period. Results Both assemblies presented low density variability over time in the lateral area due to sediment characteristics and environmental factors. Taxa Caladomyia, Parachironomus, Pristina sp., Pristina osborni, Bothrioneurum and Opistocysta funiculus were recorded at this site. The Guareí River presented both greater temporal and spatial variations, attributed mainly to a reduction in the water level. Greater organism abundance, especially of Chironomus and Tubificinae, was observed in the river. Conclusions Dissimilarity in temporal and spatial distributions of Chironomidae and Oligochaeta was attributed to peculiar characteristics of the two study sites, a river channel and a lateral area. Reduction in the water level over the year was the main controlling factor of Chironomidae and Oligochaeta richness and density in the river. In the lateral area, the presence and abundance of certain taxa were determined by the nature of the sediment and water physical and chemical variables.

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The effects of water level fluctuations and some physical and chemical variables on the macrophyte density in Lake Işıklı, Turkey

Lake and Reservoir Management ◽

10.1080/07438140809354061 ◽

2008 ◽

Vol 24 (2) ◽

pp. 196-206 ◽

Cited By ~ 2

Author(s):

Cengiz Koç

Keyword(s):

Water Level ◽

Water Level Fluctuations ◽

Physical And Chemical Variables ◽

Physical And Chemical

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Tilapia rendalli increases phytoplankton biomass of a shallow tropical lake

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x2014000400010 ◽

2014 ◽

Vol 26 (4) ◽

pp. 429-441 ◽

Cited By ~ 7

Author(s):

Lúcia Helena Sampaio da Silva ◽

Marlene Sofia Arcifa ◽

Gian Salazar-Torres ◽

Vera Lúcia de Moraes Huszar

Keyword(s):

Treatment Group ◽

Phytoplankton Biomass ◽

Experimental Period ◽

Control Group ◽

Filter Feeding ◽

Tropical Reservoir ◽

Tropical Water ◽

Tilapia Rendalli ◽

Physical And Chemical Variables ◽

Physical And Chemical

AIM: This study aimed to experimentally test the influence of a planktivorous filter-feeding fish (Tilapia rendalli) on the phytoplankton dynamics of a small and shallow tropical reservoir (Lake Monte Alegre, Brazil). Adults of T. rendalli of this lake feed preferentially on phytoplankton, and we hypothesize that: I) adults of T. rendalli will decrease the phytoplankton biomass and composition through direct herbivory, and II) as it is a eutrophic system, fish would not have strong influence on phytoplankton through nutrient cycling. METHODS: To evaluate these different effects on algae, a field experiment was performed in the summer period for 15 days, in mesocosms isolated from the sediment, using a control group (no fish) and a treatment group (with one fish in each mesocosm). Physical and chemical variables and phyto- and zooplankton were evaluated at the start, middle, and end of the experiment. RESULTS: At the end of the experiment, it was observed a significant increase in ammonium concentrations and total phytoplankton biomass, Cyanobacteria and Zygnemaphyceae and all size classes except class II (20-30 µm) in the treatment group (with fish). The biomass increase of the potentially toxic cyanobacterium Cylindrospermospsis raciborskii was also observed in the fish treatment at the end of the experimental period. CONCLUSION: This study did not support both initial hypotheses. It supports the assertion that in tropical water bodies, with similar characteristics to the environment studied, planktivorous filter-feeding fish, such as T. rendalli, are not effective in reducing phytoplankton biomass through direct grazing, even when phytoplankton is one of their main food items. T. rendalli can contribute to the increase of phytoplankton biomass and can promote or increase the eutrophication of aquatic systems.

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Implementation of Self-Organizing Maps (SOM) to analyses of environmental parameters and phytoplankton biomass in a macrotidal estuary and artificial lake

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315412000616 ◽

2012 ◽

Vol 93 (1) ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

Roksana Jahan ◽

Hyu Chang Choi ◽

Young Seuk Park ◽

Young Cheol Park ◽

Ji Ho Seo ◽

...

Keyword(s):

Phytoplankton Biomass ◽

Algal Blooms ◽

Suspended Solids ◽

Inorganic Nitrogen ◽

Environmental Parameters ◽

Ecological Data ◽

Self Organizing Maps ◽

Macrotidal Estuary ◽

Phytoplankton Communities ◽

Self Organizing

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.

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Generalized receptor law governs phototaxis in the phytoplanktonEuglena gracilis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1422922112 ◽

2015 ◽

Vol 112 (22) ◽

pp. 7045-7050 ◽

Cited By ~ 29

Author(s):

Andrea Giometto ◽

Florian Altermatt ◽

Amos Maritan ◽

Roman Stocker ◽

Andrea Rinaldo

Keyword(s):

Algal Blooms ◽

Nonlinear Response ◽

Temporal Dynamics ◽

Freshwater Ecosystems ◽

Trophic Levels ◽

Light Fields ◽

Light Sources ◽

Mathematical Framework ◽

Heterogeneous Environments ◽

Light Conditions

Phototaxis, the process through which motile organisms direct their swimming toward or away from light, is implicated in key ecological phenomena (including algal blooms and diel vertical migration) that shape the distribution, diversity, and productivity of phytoplankton and thus energy transfer to higher trophic levels in aquatic ecosystems. Phototaxis also finds important applications in biofuel reactors and microbiopropellers and is argued to serve as a benchmark for the study of biological invasions in heterogeneous environments owing to the ease of generating stochastic light fields. Despite its ecological and technological relevance, an experimentally tested, general theoretical model of phototaxis seems unavailable to date. Here, we present accurate measurements of the behavior of the algaEuglena graciliswhen exposed to controlled light fields. Analysis ofE. gracilis’ phototactic accumulation dynamics over a broad range of light intensities proves that the classic Keller–Segel mathematical framework for taxis provides an accurate description of both positive and negative phototaxis only when phototactic sensitivity is modeled by a generalized “receptor law,” a specific nonlinear response function to light intensity that drives algae toward beneficial light conditions and away from harmful ones. The proposed phototactic model captures the temporal dynamics of both cells’ accumulation toward light sources and their dispersion upon light cessation. The model could thus be of use in integrating models of vertical phytoplankton migrations in marine and freshwater ecosystems, and in the design of bioreactors.

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Limnological study of Piraquara river (Upper Iguaçu basin): spatiotemporal variation of physical and chemical variables and watershed zoning

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132003000300010 ◽

2003 ◽

Vol 46 (3) ◽

pp. 383-394 ◽

Cited By ~ 10

Author(s):

Paulo Henrique C. Marques ◽

Haydée Torres de Oliveira ◽

Eunice da Costa Machado

Keyword(s):

River Basin ◽

Oxygen Demand ◽

Principal Component ◽

Serra Do Mar ◽

Spatial Gradients ◽

Water Composition ◽

Physical And Chemical Variables ◽

Nitrite Nitrate ◽

Physical And Chemical ◽

Iguaçu River

The Piraquara river basin (Upper Iguaçu River basin - Brazil) was studied as an ecological system throughout a complete seasonal cycle, comprising the rainy and dry season. Analyzes of 16 physical and chemical water variables (dissolved oxygen, biochemical oxygen demand, temperature, pH, conductivity, total nitrogen, total phosphorus, ortophosphates, nitrite, nitrate, ammonium, reagent silicate, total suspended solids, chlorophyll - a, flow velocity and depth) showed correlations between water composition and watershed physiographic features, and the Principal Component Analysis allowed to evidence spatial gradients and seasonal differences. The sampling points were clustered in patches with homogeneous behavior, according to ecologycal concepts: patch 1, with strong influence of Serra do Mar mountains; patch 2, medium course, under Piraquara Dam influence and patch 3, under wetlands influence. Two main factors of serial discontinuity were identified: the Piraquara dam effect and the influence of wetlands. The watershed zoning based on limnological characteristics seeks to subsidize research and biomonitoring for this public springs area.

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Variations in time and space of some physical and chemical variables in the Bernesga river (León, Spain)

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/1988025 ◽

1988 ◽

Vol 24 (3) ◽

pp. 285-291 ◽

Cited By ~ 3

Author(s):

M. C. Fernandez Alaez ◽

M. Fernandez Alaez ◽

E. Luis Calabuig

Keyword(s):

Time And Space ◽

Physical And Chemical Variables ◽

Physical And Chemical

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Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x4014 ◽

2015 ◽

Vol 27 (2) ◽

pp. 171-190 ◽

Cited By ~ 8

Author(s):

Ahmed Mohamed El-Otify ◽

Isaac Agaiby Iskaros

Keyword(s):

Community Structure ◽

Zooplankton Community ◽

Water Level Fluctuations ◽

Main Stream ◽

Upper Egypt ◽

Physical And Chemical Variables ◽

Different Seasons ◽

High Current Velocity ◽

Major Nutrients ◽

Physical And Chemical

Aim: The composition, abundance, community structure of potamoplankton and major physical and chemical variables of the Nile water in Upper Egypt were investigated to assess its status in different seasons during 2007.MethodsWater samples were collected seasonally during 2007 from six investigated sites from variable depths at levels of 0, 2.5 and 5 m. The area of this investigation is defined as the southern 120 Km of the main stream of the Nile in Upper Egypt (24° 04’ – 25° 00’ latitudes and 32° 51’ – 32° 54’ longitudes), downstream of Aswan Old Dam.ResultsAltogether, 121 potamoplankton species, of which 85 related to phytoplankton and 36 appertaining to zooplankton were recorded. Most numerous phytoplankton were Chlorophyceae (42 species) followed by Bacillariophyceae (30 species). Cyanobacteria and Dinophyceae were less numerous with only 11 and 2 species, respectively. Zooplankton species were mainly belonging to three systematic groups namely; Rotifera (24 species), Copepoda (3 species) and Cladocera (9 species). Besides, other rare zooplankton including Platyhelminthes, Nemata and Ciliophora were sparsely encountered. The main hydrological conditions characterizing the investigated area include water level fluctuations (˂82 - ˃85 m above sea level), relatively high current velocity (0.8 - 1.3 m sec–1) and disposal of wastewater. Plankton populations were variably but rather weakly dependent on the major nutrients due to their excessive availability in accessible form for uptake by the producers. For phytoplankton, the community structure was categorized in relation to temperature, pH, SO42– and Mg2+. For zooplankton, the community structure was categorized in relation to conductivity as well as Mg2+. Sampling intervals were inadequate to demonstrate the existing successional pattern of the Nile potamoplankton community. Alterations in the phytoplankton community structure accompanied changes in water temperature represented by the alternate dominance between diatoms and cyanobacteria, while zooplankton community was always dominated by rotifers. Phytoplankton populations were numerically more abundant in autumn and zooplankton peaked in spring.ConclusionsWastewater disposal restricted the abundance of the Nile zooplankton assemblages mainly due to the numerical decline of Rotifera and Cladocera. Otherwise, wastewater did not exert major limits for phytoplankton. The data obtained in this investigation will be crucial to understand potamoplankton regulation and contribute to the knowledge regarding the Limnology of the Nile basin.

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Photosynthetic response to nitrogen source and different ratios of nitrogen and phosphorus in toxic cyanobacteria, Microcystis aeruginosa FACHB-905

Journal of Limnology ◽

10.4081/jlimnol.2016.1458 ◽

2016 ◽

Cited By ~ 3

Author(s):

Guotao Peng ◽

Zhengqiu Fan ◽

Xiangrong Wang ◽

Chen Chen

Keyword(s):

Chlorophyll Fluorescence ◽

Algal Blooms ◽

Freshwater Ecosystems ◽

Cyanobacterial Blooms ◽

Photosynthetic Response ◽

Nitrogen And Phosphorus ◽

Ammonium Toxicity ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

N Assimilation

The frequent outbreak of cyanobacterial blooms has become a worldwide phenomenon in freshwater ecosystems. Studies have elucidated the close relationship between harmful algal blooms and nutrient contents, including the loading of nitrogen and the ratios of nitrogen (N) and phosphorus (P). In this study, the effect of inorganic (nitrate and ammonium) and organic (urea) nitrogen at varied N/P ratios on the Microcystis aeruginosa FACHB-905 accumulation and photosynthesis was investigated. The optimal NO3/P in this study were 30~50 indicated by the cell abundance (4.1×106/mL), pigment concentration (chlorophyll a 3.1 mg/L, phycocyanin 8.3mg/L), and chlorophyll fluorescence parameters (rETR, Ek, α, φPSII and Fv/Fm values), while too high NO3-N (N/P=100:1) would cause an intracellular nitrate inhibition, leading to a decrease of photosynthetic activity. In addition, low concentration of NH4-N (N/P=4:1) would favor the M. aeruginosa growth and photosynthesis, and high NH4/P ratio (>16) would rise the ammonium toxicity of algal cells and affect the N assimilation. In urea treatments, M. aeruginosa responded similarly to the NH4-N treatments both in growth curves and pigment contents, and the favorable N/P ratio was between 16~30, suggested by the chlorophyll fluorescence parameters. The results demonstrated that the various chemical forms of N and N/P ratios have a significant impact on Microcystis abundance and photosynthesis. More work is needed to figure out the mechanism of nitrogen utilization by Microcystis and the photosynthetic response to nutrient stress at the molecular level.

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