scholarly journals Vertical and temporal dynamics of phytoplanktonic associations and the application of index assembly in tropical semi-arid eutrophic reservoir, northeastern Brazil

2015 ◽  
Vol 27 (1) ◽  
pp. 130-144 ◽  
Author(s):  
Pryscila Cynara Soares Vieira ◽  
Maria Marcolina Lima Cardoso ◽  
Ivaneide Alves Soares da Costa
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Functional Groups ◽  
Phytoplankton Community ◽  
Temporal Dynamics ◽  
Temporal Variations ◽  
Northeastern Brazil ◽  
Quality Of Water ◽  
Q Index ◽  
Semi Arid

AimTo determine the composition and biomass of functional groups around the vertical and temporal gradient correlated with environmental conditions and apply the index Q in a water-supply reservoir.MethodsWater samples were collected monthly (n = 92) between 2009 and 2011 in two points of the dam for physicochemical and biological analysis.ResultsThe pH, dissolved oxygen and water temperature showed significant differences between the photic and aphotic zones (p<0.05). The vertical variation of dissolved oxygen and water temperature, showed a profile of stratification. The phytoplankton community was represented by 11 functional groups: S1, M, H1, Lo, P, F, SN, J, W2, MP and R.ConclusionsThe vertical variations were less pronounced than the temporal variations in the phytoplankton community. The Q index pointed out poor water quality, corresponding to the current state of eutrophication in the reservoir and it was sensitive to responsive to environmental and hydrodynamic changes in these systems, demonstrating to be an appropriate tool for monitoring and evaluating the quality of water in tropical semi-arid reservoirs.

scholarly journals Morphofunctional changes of phytoplankton community during pluvial anomaly in a tropical reservoir

2015 ◽  
Vol 75 (3) ◽  
pp. 628-637 ◽  
Author(s):  
FRA Câmara ◽  
O Rocha ◽  
EKR Pessoa ◽  
S Chellappa ◽  
NT Chellappa
Keyword(s):  
Species Diversity ◽  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Phytoplankton Community ◽  
Diversity Index ◽  
Hydrodynamic Instability ◽  
Electrical Conductance ◽  
Northeastern Brazil ◽  
Tropical Reservoir ◽  
Cyanobacterial Species

AbstractThe present study focuses on the structure and function of phytoplankton community during periods of marked changes in hydrological traits, influenced by an atypical climatic event (La Niña) and its impact on Armando Ribeiro Gonçalves Reservoir of Rio Grande do Norte, situated in the Caatinga biome of northeastern Brazil. The main questions addressed were: What are the effects of environmental factors on the temporal variation of Morphologically Based Functional Group (MBFG) of phytoplankton community? How does the composition of cyanobacterial species shift in relation to high and low trends of phytoplankton diversity? The samples were collected monthly during 2008-2009 and analyzed for pH, temperature, electrical conductivity, dissolved oxygen content and the nutrients, such as, nitrate-nitrogen, ammoniacal nitrogen, total nitrogen and orthophosphate. Phytoplankton samples were collected for both qualitative and quantitative analyses to evaluate species richness index and species diversity index. The data was divided into two distinct hydrodynamic periods of instability and stability. The results demonstrate considerable changes in dissolved oxygen content, water transparency and nitrogen nutrients, which directly influenced the MBFG of phytoplankton community in space and time. The instability of reservoir water was caused by heavy rainfall, which exerts atypical external disturbances. The seasonal variation of MBFG demonstrates a change in cyanobacterial composition and their diversity during instability and stability periods. MBFG VII, composed by colonial cyanobacteria with mucilage, was associated with reduced values of electrical conductance and alterations in pH. The predominance of filamentous species with heterocyst (MBFG III) occurs only during the hydrodynamic stability period and did not show significant association with analyzed parameters. The co-dominance of MBGFs III, V and VII along with high species diversity of phytoplankton community occurred during the second hydrodynamic instability period which was associated with the reduction in water temperature. It is concluded that the decrease in cyanobacterial species dominance and the general increase in the diversity of phytoplankton community are influenced by pluvial anomaly. The higher water level during the period of pluvial anomaly resulted in nutrient pulse and the mixing of water column in the reservoir, which determined the MBPG phytoplankton community distribution.

scholarly journals Zooplankton assemblages in eutrophic reservoirs of the Brazilian semi-arid

2013 ◽  
Vol 73 (1) ◽  
pp. 37-52 ◽  
Author(s):  
EM. Eskinazi-Sant'Anna ◽  
R. Menezes ◽  
IS. Costa ◽  
M. Araújo ◽  
R. Panosso ◽  
...  
Keyword(s):  
Arid Region ◽  
Temporal Dynamics ◽  
Spatial Differentiation ◽  
Zooplankton Community ◽  
Northeastern Brazil ◽  
Calanoid Copepods ◽  
Phytoplankton Assemblages ◽  
Semi Arid Region ◽  
Eutrophic Reservoirs ◽  
Semi Arid

Species composition, density, and temporal dynamics of zooplankton were studied in six reservoirs in a semi-arid region in tropical northeastern Brazil (Rio Grande do Norte state). All the reservoirs are highly eutrophic, with high contents of total nitrogen (minimum of 1200 µg.L-1) and total phosphorus (minimum of 10 µg.L-1), and extremely high algal biomass was registered (surpassing 20 µg Chl a.L-1). All the reservoirs showed an enduring condition of high turbidity and phytoplankton assemblages dominated by cyanobacteria. Zooplankton also showed quantitative patterns suggestive of eutrophic conditions, expressed by high densities, mainly in Passagem das Traíras and Sabugi reservoirs. A spatial differentiation in the composition of the zooplankton community was registered. Rotifers (especially Keratella tropica, Brachionus havanensis, and Keratella americana) were the dominant forms in the zooplankton community of Itans, Passagem das Traíras, and Sabugi reservoirs, while calanoid copepods (mainly Notodiaptomus cearensis) dominated in the Armando Ribeiro, Gargalheiras, and Parelhas systems. The existence of novel relationships in zooplankton community composition in eutrophic reservoirs in this tropical semi-arid region must be considered in designating zooplankton indicators of eutrophic conditions.

scholarly journals CHANGES IN CONCENTRATIONS OF ORGANIC MATTER IN THE MOUTHS OF THE DOTNUVELE AND SMILGA RIVERS

2018 ◽  
Author(s):  
Stefanija MISEVIČIENĖ
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Anthropogenic Activities ◽  
Precipitation Amount ◽  
Ecological Status ◽  
Sources Of Pollution ◽  
Temperature And Precipitation ◽  
Quality Of Water ◽  
The Difference

The quality of water in rivers of central Lithuania is often bad due to intensive anthropogenic activities. When rivers flow through the town’s territory, concentrated pollution, such as rainwater, industrial and productional waste water discharges, contributes to diffuse sources of pollution. If biogenic substances are the main indicators for diffuse pollution, organic matter, expressed as BOD, is the indicator for concentrated pollution. The article provides the 2013 – 2017 monitoring data on the changes of organic matter in the water of the Dotnuvele and Smilga Rivers and discusses the reasons for fluctuations in concentrations of BOD7. The aim of the research is to investigate the changes in the organic matter of the Dotnuvele and Smilga Rivers, depending on meteorological factors. For chemical analysis, water samples were taken quarterly. Water analysis was carried out by the ASU Chemical Analytical Laboratory of Water Resources Engineering Institute. The amount of organic matter (BOD7) is calculated as the difference in oxygen content after 7 days of incubation, while the amount of dissolved oxygen (O2) in the water is determined by the electrochemical probe method. The concentrations of BOD7 and O2 in the water of both rivers is compared with the criteria for assessing the ecological status of surface water bodies. The research has shown that the dissolved oxygen concentrations in rivers’ water are strongly influenced by water temperature and precipitation. The lower the temperature, the more of the dissolved oxygen is found in rivers’ water (r = -0.64). A lower precipitation amount, which reaches the rivers, increases the amount of dissolved oxygen in them (r = -0.45). The increase of BOD7 concentrations in rivers’ water was caused by higher precipitation amount (r = 0.46), higher air (r = 0.41) and lower water temperature (r = -0.41). The ecological status of the Dotnuvele River was usually good, while Smilga was average.

scholarly journals Vertical and temporal dynamics of cyanobacteria in the Carpina potable water reservoir in northeastern Brazil

2011 ◽  
Vol 71 (2) ◽  
pp. 451-459 ◽  
Author(s):  
AN Moura ◽  
EW Dantas ◽  
HSB Oliveira ◽  
MC Bittencourt-Oliveira
Keyword(s):  
Water Column ◽  
Potable Water ◽  
Temporal Dynamics ◽  
Water Reservoir ◽  
Optical Microscope ◽  
Temporal Variations ◽  
Northeastern Brazil ◽  
Cyanobacterial Blooms ◽  
Cylindrospermopsis Raciborskii

This study analysed vertical and temporal variations of cyanobacteria in a potable water supply in northeastern Brazil. Samples were collected from four reservoir depths in the four months; September and December 2007; and March and June 2008. The water samples for the determination of nutrients and cyanobacteria were collected using a horizontal van Dorn bottle. The samples were preserved in 4% formaldehyde for taxonomic analysis using an optical microscope, and water aliquots were preserved in acetic Lugol solution for determination of density using an inverted microscope. High water temperatures, alkaline pH, low transparency, high phosphorous content and limited nitrogen content were found throughout the study. Dissolved oxygen stratification occurred throughout the study period whereas temperature stratification occurred in all sampling months, with the exception of June. No significant vertical differences were recorded for turbidity or total and dissolved forms of nutrients. There were high levels of biomass arising from Planktothrix agardhii, Cylindrospermopsis raciborskii, Geitlerinema amphibium and Pseudanabaena catenata. The study demonstrates that, in a tropical eutrophic environment with high temperatures throughout the water column, perennial multi-species cyanobacterial blooms, formed by species capable of regulating their position in the water column (those that have gas vesicles for buoyancy), are dominant in the photic and aphotic strata.

scholarly journals Biomonitoring ecological status of two reservoirs of the Brazilian semi-arid using phytoplankton assemblages (Q index)

2015 ◽  
Vol 27 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Ana Paula Cardoso Silva ◽  
Ivaneide Alves Soares da Costa
Keyword(s):  
Phytoplankton Community ◽  
Ecological Status ◽  
Sample Period ◽  
Phytoplankton Composition ◽  
Santa Cruz ◽  
Phytoplankton Assemblages ◽  
Total Phytoplankton ◽  
Moderate Condition ◽  
Q Index ◽  
Semi Arid

AimAssess whether the assembly index is a suitable tool for biomonitoring of aquatic ecosystems of semi-arid environment.MethodsMonthly, samples were collected between October 2011 and May 2012 in Santa Cruz do Apodi (5°43'59"S; 46" 00 119 "W) and Pau dos Ferros (6°08'30.12" S; 038°10'59 880"W) reservoirs.ResultsThe Pau dos Ferros reservoir, shallow, turbid and eutrophic showed dominance of the functional group SN throughout the sample period. Total phytoplankton biovolume ranged between 20 and 70 mm³.L–1, the lowest values coincided with the increase of the mixing zone and transparency, which occasioned a change in composition of the phytoplankton community. Pau dos Ferros reservoir was categorized as poor for most of the sample period. The Santa Cruz do Apodi reservoir was characterized as meso-eutrophic, exhibiting low total phytoplankton biovolume (0.04 to 0,4 mm³.L–1) and greater diversity in the phytoplankton composition. It showed moderate condition during most of the period.ConclusionIn summary, the index Q reflected well the changes in phytoplankton composition, being a good indicator for biomonitoring of these systems.

A study on bioecology of macroalgae, genus Caulerpa in northern Minahasa Waters, North Sulawesi Province

2013 ◽  
Vol 1 (1) ◽  
pp. 26
Author(s):  
Irma Pulukadan ◽  
Rene Ch Keppel ◽  
Grevo S Gerung
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Raw Materials ◽  
Economic Value ◽  
Algal Growth ◽  
Environmental Parameters ◽  
Caulerpa Racemosa ◽  
Bottom Substrate ◽  
North Sulawesi ◽  
Ecological Aspects

Alga is a marine resource of potential to fisheries and marine sector. It has an important economic value to promote the economy in Indonesia. Nowdays, algae have been used as a relatively high value fisheries commodity since it has been used for food, industrial, pharmaceutical and cosmetic raw materials. This important potential needs to be supported with understanding of its biology and ecology, so that its utilization could increase the livelihood of the coastal villagers. This study was aimed at inventorying and identifying the members of genus Caulerpa found in North Minahasa Regency waters and studying some biological and ecological aspects of the algae in the area. Resuls showed that there were 7 species recorded, Caulerpa racemosa, C. racemosa var. macrophysa, C. sertularioides, C. taxifolia, C. serrulata,C. lentillifera and C. peltata. Ecologically, the environmental parameters, such as water temperature, salinity, pH, dissolved oxygen, turbidity, were in tolerable ranges for algal growth. Bottom substrate supported the growth of genus Caulerpa as well© Saat ini alga dijadikan sebagai komoditas hasil perikanan dengan nilai ekonomis yang relatif tinggi karena manfaatnya sebagai bahan makanan serta bahan baku industri, farmasi, dan kosmetik. Potensi yang cukup penting ini harus ditunjang dengan ilmu pengetahuan tentang biologi dan ekologi dari alga laut, sehingga pemanfaatannya dapat meningkatkan taraf hidup masyarakat pesisir. Penelitian tentang kajian bioekologi alga makro genus Caulerpa di perairan Minahasa Utara ini dilaksanakan dan diharapkan dapat memberikan informasi ilmiah tentang bioekologi alga makro genus Caulerpa, sehingga dapat dimanfaatkan untuk pengembangan pemanfaatan bagi kepentingan masyarakat pesisir khususnya dan industri alga makro umumnya. Penelitian ini bertujuan untuk menginventarisasi dan mengidentifikasi alga makro genus Caulerpa di perairan Kabupaten Minahasa Utara, dan mengkaji aspek bioekologinya. Hasil penelitian menunjukkan bahwa ditemukan 7 spesies, yaitu Caulerpa racemosa, C. racemosa var. macrophysa, C. sertularioides, C. taxifolia, C. serrulata, C. lentillifera dan C. peltata. Parameter lingkungan seperti suhu, salinitas, pH, oksigen terlarut, tingkat kecerahan air berada pada kisaran yang dapat ditolerir untuk pertumbuhan alga makro, sedangkan substrat juga mendukung pertumbuhan alga makro ini©

scholarly journals Surface Water Temperature Predictions at a Mid-Latitude Reservoir under Long-Term Climate Change Impacts Using a Deep Neural Network Coupled with a Transfer Learning Approach

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1109
Author(s):  
Nobuaki Kimura ◽  
Kei Ishida ◽  
Daichi Baba
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Water Temperature ◽  
Transfer Learning ◽  
Air Temperature ◽  
Climate Models ◽  
Temporal Variations ◽  
Training Data ◽  
Surface Water Temperature

Long-term climate change may strongly affect the aquatic environment in mid-latitude water resources. In particular, it can be demonstrated that temporal variations in surface water temperature in a reservoir have strong responses to air temperature. We adopted deep neural networks (DNNs) to understand the long-term relationships between air temperature and surface water temperature, because DNNs can easily deal with nonlinear data, including uncertainties, that are obtained in complicated climate and aquatic systems. In general, DNNs cannot appropriately predict unexperienced data (i.e., out-of-range training data), such as future water temperature. To improve this limitation, our idea is to introduce a transfer learning (TL) approach. The observed data were used to train a DNN-based model. Continuous data (i.e., air temperature) ranging over 150 years to pre-training to climate change, which were obtained from climate models and include a downscaling model, were used to predict past and future surface water temperatures in the reservoir. The results showed that the DNN-based model with the TL approach was able to approximately predict based on the difference between past and future air temperatures. The model suggested that the occurrences in the highest water temperature increased, and the occurrences in the lowest water temperature decreased in the future predictions.

scholarly journals Simulating Diurnal Variations of Water Temperature and Dissolved Oxygen in Shallow Minnesota Lakes

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1980
Author(s):  
Bushra Tasnim ◽  
Jalil A. Jamily ◽  
Xing Fang ◽  
Yangen Zhou ◽  
Joel S. Hayworth
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Shallow Lakes ◽  
Quality Model ◽  
Lake Water Quality ◽  
Ecological Processes ◽  
Turbulent Diffusion Coefficient ◽  
Hourly Data ◽  
Mean Square Errors

In shallow lakes, water quality is mostly affected by weather conditions and some ecological processes which vary throughout the day. To understand and model diurnal-nocturnal variations, a deterministic, one-dimensional hourly lake water quality model MINLAKE2018 was modified from daily MINLAKE2012, and applied to five shallow lakes in Minnesota to simulate water temperature and dissolved oxygen (DO) over multiple years. A maximum diurnal water temperature variation of 11.40 °C and DO variation of 5.63 mg/L were simulated. The root-mean-square errors (RMSEs) of simulated hourly surface temperatures in five lakes range from 1.19 to 1.95 °C when compared with hourly data over 4–8 years. The RMSEs of temperature and DO simulations from MINLAKE2018 decreased by 17.3% and 18.2%, respectively, and Nash-Sutcliffe efficiency increased by 10.3% and 66.7%, respectively; indicating the hourly model performs better in comparison to daily MINLAKE2012. The hourly model uses variable hourly wind speeds to determine the turbulent diffusion coefficient in the epilimnion and produces more hours of temperature and DO stratification including stratification that lasted several hours on some of the days. The hourly model includes direct solar radiation heating to the bottom sediment that decreases magnitude of heat flux from or to the sediment.

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