Thesis (MSc. Agriculture (Soil Science)) -- University of Limpopo, 2014 / Phosphorus (P) runoff from agricultural sites and the subsequent loading into surface water bodies contribute to eutrophication. Environmental concerns associated with P loading in soil have motivated the need for the development of a proper tool that will allow farmers to identify agricultural areas or management practices that have the greatest potential to accelerate eutrophication. The objective of the study was to determine the spatial variability of soil test P, soil loss potential of the farm, P application rate and methods, and map P runoff risk across the field. This study was conducted in Vierfontein Boerdery in Kriel, Mpumalanga province, South Africa (longitude 29.11258833 and latitude -26.27104340). The field was under dryland cultivation and planted to yellow maize that was rotated with soybeans. Soil samples were taken at georeferenced locations in a 100 x 100 m grid for soil analysis. Spatial layers of soil P distribution, soil loss potential as well as application rate and method were created in ArcGIS software. These layers were used as input factors in a P index model to identify areas in the farm that are vulnerable to P runoff. Results indicated a variation in soil test P. Although soil test P variation was not statistically different at P≤0.05, variation had both agronomic and environmental implications. This variation could be attributed to differences in site-specific conditions and management practices. Furthermore, soil loss potential across the study site predicted by the Revised Universal Soil Loss Equation (RUSLE) showed variation with a range of 3-15 tons/ha/yr. This variation was attributed to differences in topographic variations in the study site. There is a need for best management practices that control soil erosion to minimize P runoff into water bodies. KEYWORDS: Eutrophication, Geographic Information System, Phosphorus best management practises, Phosphorus runoff index, Soil erosion, Site-specific management.

Thesis (M.S.)--State University of New York at Binghamton, Department of Biological Sciences, 2008. / Includes bibliographical references.

Three coastal Oregon dunal lakes, Mercer Lake, Munsel Lake, and Woahink Lake, were studied in an effort to determine if eutrophication has occurred since initial studies were conducted in 1938 and to determine each lake's current trophic status. Data collected in 1991 and 1992 for phytoplankton primary productivity; chlorophyll gi phytoplankton species, biovolumes, and densities; nutrients; optical characteristics; and dissolved oxygen were compared with historical data sets. Additional data for zooplankton, benthic invertebrates, and other relevant limnological data were used to more completely characterize each lake. Phytoplankton primary productivity measurements indicate that biological productivity has increased at each lake since 1969-1971. Chlorophyll ~ concentrations appear to have increased only at Mercer Lake. Other limnological data are insufficient to determine if and to what extent these lakes have eutrophicated. Based on data collected in 1991 and 1992, the current trophic state of each lake can be described as follows: Mercer Lake is mesotrophic to eutrophic but closer to mesotrophic, Munsel Lake is oligotrophic to mesotrophic but closer to mesotrophic, and Woahink Lake is oligotrophic to mesotrophic but closer to oligotrophic.

Μία από τις πιο σημαντικές περιβαλλοντικές απειλές των υδάτινων συστημάτων αποτελεί ο ευτροφισμός. Αυτός νοείται ως ο εμπλουτισμός των υδάτων ενός συστήματος με ανόργανα θρεπτικά, κυρίως άλατα, αζώτου και φωσφόρου με άμεσο αποτέλεσμα την αύξηση της πρωτογενούς παραγωγής και τελικές επιπτώσεις την αλλαγή του συνόλου της βιοποικιλότητας και την υποβάθμιση του υδάτινου περιβάλλοντος. Στόχος της παρούσας διπλωματικής εργασίας είναι η εκτίμηση της ποιότητας των υδάτων σε περιβάλλον ανάμειξης γλυκού και αλμυρού νερού στις εκβολές του ποταμού Ευήνου και Γλαύκου καθώς επίσης και ο καθορισμός του βαθμού επίδρασης του γλυκού νερού στο θαλάσσιο πεδίο. Για το λόγο αυτό πραγματοποιήθηκαν δειγματοληψίες επιφανειακών υδάτων σε σημεία εντός της κοίτης του ποταμού Εύηνου και της εκβολής του σε δύο περιόδους (23/10/2012 και 27/5/2013). Επίσης έγιναν δειγματοληψίες νερού θαλάσσιας στήλης σε βάθη 0,2,10,15 και 20 μέτρων σε αυξανόμενες αποστάσεις από το σημείο εκβολής του ποταμού Γλαύκου στον Πατραϊκό Κόλπο. Διεξήχθησαν δειγματοληψίες σε διαφορετικές περιόδους ως εξης: 1/12/2012, 1/2/2013, 28/3/2013, 19/4/2013 και 27/5/2013. Τα δείγματα αναλύθηκαν και έγιναν μετρήσεις για τις πιο κάτω παραμέτρους: νιτρικά και φωσφορικά άλατα, pH, ηλεκτρική αγωγιμότητα. Η αξιολόγηση των εργαστηριακών αποτελεσμάτων έγιναν με τη βοήθεια διαγραμμάτων που κατασκευάστηκαν ώστε να βρεθούν οι μεταβολές των ανωτέρω παραμέτρων ως προς το βάθος του νερού, οι μεταβολές των παραμέτρων ως προς την απόσταση από την εκβολή και οι διαχρονικές μεταβολές των παραμέτρων. Γενικά από την αξιολόγηση των αποτελεσμάτων προκύπτει ότι : 1. Για τον Ποταμό Εύηνο οι μεγαλύτερες συγκεντρώσεις των θρεπτικών εμφανίστηκαν εντός του ποταμού και για τις δύο δειγματοληψίες. Οι συγκεντρώσεις μειώνονται προς την εκβολή. 2. Στις εκβολές του Ποταμού Γλαύκου εμφανίστηκε μείωση της συγκέντρωσης των θρεπτικών αλάτων σε συνάρτηση με το βάθος. Η πλειοψηφία των μέγιστων συγκεντρώσεων εντοπίστηκε στην επιφάνεια είτε στο μικρό βάθος των 2 μέτρων . 3. Επιπλέον, οι μικρότερες συγκεντρώσεις νιτρικών εντοπίστηκαν την υγρή περίοδο (Μάρτης-Απρίλιος 2013). Αντίθετα, την ίδια περίοδο εμφανίστηκαν οι μεγαλύτερες συγκεντρώσεις φωσφορικών. 4. Η θετική συσχέτιση της ηλεκτρικής αγωγιμότητας με τη συγκέντρωση των νιτρικών δηλώνει ότι οι μεγαλύτερες συγκεντρώσεις νιτρικών εμφανίζονται στα αλμυρά νερά. 5. Το αντίθετο φαινόμενο συνέβη για τα φωσφορικά κάτι που δηλώνει ότι ο ποταμός Γλαύκος εμπλουτίζει με φωσφορικά τον Πατραϊκό Κόλπο. 6. Συγκριτικά με τη βιβλιογραφία οι τιμές των θρεπτικών αλάτων στις εκβολές Ευήνου και Γλαύκου, εμφανίζονται μεγαλύτερες με εκείνες σε εκβολές άλλων ελληνικών ποταμών. Για τον Ποταμό Εύηνο αυτό πιθανά οφείλεται στην γεωργική δραστηριότητα στη λεκάνη απορροής του, ενώ για τον Ποταμό Γλαύκο οφείλεται στις έντονες ανθρώπινες πιέσεις του μεγάλου πολεοδομικού συγκροτήματος της Πάτρας. / Eutrophication is one of the most significant environmental threats to natural water systems. It is the enrichment of water with inorganic nutrients, mainly salts, such as nitrogen and phosphorus, resulting in increase of primary production with final impact in biodiversity and the degradation of the aquatic environment. The aim of the present Master Thesis is to assess the water quality in a mixing fresh -salt water estuary of rivers Evinos and Glafkos as well as setting the effect of freshwater into the marine field. For this reason, samplings were conducted, surface water samples were collected into the river bed and outfall of Evinos River in two periods (23/10/2012 and 27/5/2013). In addition, water samples were collected at depths 0,2,10,15 and 20m at increasing distances from the outfall of Glafkos river in Patraikos Gulf. Samplings were conducted in different periods as follows: 1/12/2012, 1/2/2013, 28/3/2013, 19/4/2013 και 27/5/2013. Water samples were analyzed and measurements were made for the following parameters: Nitrates and Phosphates, pH and Electrical conductivity. Evaluation of laboratory results were made with diagrams, constructed in order to find changes in the above parameters versus water depth, also changes between these parameters and the distance from the river mouth and the temporal changes of measured parameters. In general, from the evaluation, the results indicate that: 1. In Evinos River maximum nutrient concentrations occurred in the river bed for both samplings periods. Concentrations reduced from the river bed to the outfall. 2. In Glafkos outfall a decline of nutrients concentration was observed in relation to depth. The majority of the maximum concentrations were detected in the surface or at shallow depth of 2 m. 3. Moreover, minimum nitrate concentrations were detected at Wet season (March-April 2013). In contrast, in the same period occurred the maximum phosphate concentrations. 4. The positive correlation between electrical conductivity and nitrate concentration indicate that the highest concentrations of nitrate occur in salt water. 5. The opposite effect occurred for phosphates which indicate that the river Glafkos enriches with phosphates the Gulf of Patras. 6. In comparison with the literature, nutrient concentrations in Evinos and Glafkos outfalls appeared to be greater to those in other Greek rivers. This is probably due to agricultural activity in the catchment basin of Evinos River, and due to intense human pressures of Patras in the Glafkos River respectively.

Coastal and shallow lakes are often subjected to eutrophication due to nutrients from catchment farming activities. Lake Ellesmere (Te Waihora) is a hyper-eutrophic lake which has gained recent attention because of concerns over its ecological health and fishery status. This study investigated the benthic ecology of the lake by extensive spatial and temporal sampling. Eight littoral sites were sampled on a single occasion, and 20 benthic sites were sampled once per season for one year. Water chemistry conditions, substrate and invertebrate communities varied significantly around the lake. Salinity, pH, DO and seston were primarily affected by freshwater inputs from inflow streams and salt water intrusion due to the lake opening to the sea. On these occasions, salinity reached 32 ‰ at the lake outlet. The lake invertebrate community was depauperate, comprising of only two species of invertebrate predators restricted to the littoral zone and eight benthic invertebrate taxa, dominated by oligochaetes, amphipods and chironomids. Benthic invertebrate abundances also reflect the dominant local substrate, where oligochaetes and chironomids preferred areas of silt substrate, whereas Potamopyrgus preferred harder substrate. Stable isotope and gut analysis determined that the primary food sources within the lake were phytoplankton and algae. Macrophytes provided a minimal contribution to the food web, possibly relating to the change in status from a clear water, macrophyte dominated lake to a turbid, phytoplankton dominated condition since the Wahine Storm in 1968. Isotope analysis also showed that the lake food web was markedly different in its carbon values from food webs of its inflow streams and nearby marine source. However the lake food web did show a marine-derived carbon signature. A mesocosm experiment testing the effect of common lentic predators on the abundance of the lake chironomid Chironomus zealandicus, showed that if invertebrate predators were present in the lake they could markedly reduce the abundance of the pest prey species. This study highlights that the frequent re-suspension of bottom sediments, lake level fluctuation resulting in wetting and drying of littoral zones, and the management of the lake opening to the sea all have an effect on the benthic ecology of Te Waihora.

One of today's major environmental issues is algal blooms linked to eutrophication of lakes and oceans. That is a result of anthropogenic influence with nutrient loads (including phosphorus) from agriculture and industry, which benefits primary production (phytoplankton). Studies have shown that phosphorus availability in the water column can be limited by liming, therefore could be a way to counteract eutrophication. This was tested in the agriculturally surrounded lake Tåkern in southern Sweden, which in its present state is an internationally important bird lake and therefore in several respects would be affected by eutrophication. The purpose of this study was to investigate whether liming would be a good solution to solve any future eutrophication problems in Lake Tåkern. Liming experiments were performed in mesocosms during April 2015 with a mixture of limestone and slaked lime. Quantity and diversity of plankton and water chemical variables were measured before and after liming. Moreover, samples of phytoplankton from a similar experiment conducted in July 2014 were analyzed. Liming did not show any effect on neither phyto- nor zooplankton when performed in spring of 2015. During summer of 2014, there was an increase in number of phytoplankton (ml-1 ) and chlorophyll in controls while the study showed constant levels in treated mesocosms. For zooplankton there was no significant effects of liming on neither quantity nor diversity. Results of this study suggest that liming is not the most appropriate method to resolve eutrophication in Lake Tåkern.

: In freshwater systems phosphorus (P) is the limiting element in the cause of eutrophication. In many Swedish lakes, causes of eutrophication have been attributed to more of internal loading than external since the external loading has been fairly well managed. Internal loading is linked to the mobility of sediment P, which are known to be Bioavailable P (BAP). Sediments from Lake Hällerstadsjön in Sweden was studied to know the BAP concentration and its possible release into the water column under reduced conditions. Sediments were sampled at two different depths, 0-5 cm and 5-10cm. BAP was determined by a phosphorus fractionation scheme. Sediments were incubated under oxic and anoxic conditions in the laboratory to evaluate sediment P release. Spatial variation in the distribution of P forms across the lake was also studied, in order to examine possible local patterns, particularly along a transect from the main inlet to the outlet. Fractionation analyses showed a trend of; Residual-P > NaOH-P > HCl-P > BD-P > Loosely bound P. The fractions constituting the BAP was higher at the 0-5 cm sediment depth than 5-10 cm. Sediment P flux was recorded for anoxic but not oxic sediment. BAP correlated significantly with sediment P flux (P= 0.01). Spatially, the P distribution varied both at depths and along a latitudinal transect, from the main inlet to the outlet.  Dredging of the surface sediments with high BAP content would possibly be an effective means of preventing eutrophication of the lake.

Considerando a importância da represa do Lobo, os indícios de eutrofização encontrados na área e tendo a recreação como seu principal uso, buscou-se, neste trabalho, avaliar a qualidade da água nos rios tributários e na represa, e sua adequação a balneabilidade. Para os afluentes do sistema, estimando-se, ainda, a contribuição dos mesmos ao aporte de materiais à represa, foram amostrados o córrego do Geraldo, a confluência dos córregos Água Branca e Limoeiro, o rio Itaqueri (antes da mineradora), o ribeirão do Lobo, o córrego das Perdizes, avaliando-se parâmetros físicos, químicos e biológicos da água e a vazão dos rios, em dois períodos (agosto/setembro e dezembro) de 2002. Os resultados, com base no índice de estado trófico, indicam que a maioria dos tributários, com exceção do córrego Água Branca (eutrófico), é oligotrófico. Na represa o estudo teve avaliações mensais para alguns parâmetros (nutrientes totais e dissolvidos, clorofila total e material em suspensão) e semanais para outros (pH, condutividade elétrica, temperatura da água, oxigênio dissolvido e coliformes fecais) ao longo de um ano (dezembro de 2001 a dezembro de 2002), em nove pontos, abrangendo a região de foz do rio Itaqueri, córrego do Geraldo e ribeirão do Lobo, quatro pontos distribuídos na praia do balneário Santo Antônio e um ponto a jusante da represa. A foz do rio Itaqueri apresentou-se meso-eutrófica no período, enquanto os outros pontos avaliados, oligotróficos. Apesar da condição favorável apresentada, a análise temporal dos dados (com estudos realizados nos últimos 30 anos), mostra uma evidente e preocupante alteração nas condições originárias desse sistema, indicando um evidente processo de eutrofização do reservatório, associado aos usos e ocupação da bacia hidrográfica (resíduos domiciliares, turismo, agricultura e pecuária). Em relação a balneabilidade os principais pontos de contaminação fecal na represa são as entradas dos tributários, enquanto o corpo da represa foi considerado excelente em todo o período amostrado. O córrego Água Branca, como corpo receptor do esgoto de Itirapina, é o mais comprometido dos corpos de água avaliados, além de ser o principal contribuinte de nutrientes e coliformes fecais para a represa do Lobo, através do rio Itaqueri. / Considering the importance of the Lobo reservoir, the sights of eutrophication found in the area and having recreation as its main usage, it has been tried, in the following paper, to evaluate the water quality in the tributary rivers and also in the reservoir as well as its adequacy to balneability. As main tributaries of the system, estimating yet their contribution to the input of materials to the reservoir, there have been sampled the Geraldo river, the meeting of Água Branca and Limoeiro rivers, the Itaqueri river (before the mining plant), the Lobo river, the Perdizes river, evaluating their physical, chemical and biological parameters and the rivers leakage during two different periods of time (August/September and December) from 2002. The results, which are based in the amount of trophic state, show that most of the tributaries, excepting the Água Branca river (eutrophic) are oligotrophic. In the reservoir, the evaluation has been more systematic, with monthly evaluations to some parameters (amount of total nutrients and dissolved nutrients, total chlorophyll and suspended material) and weekly evaluation to others (pH, electrical conductivity, water temperature, dissolved oxygen and fecal coliforms), during the period of one year (December, 2001 to December, 2002), in nine sites considering the region of the mouth of the rivers Itaqueri, Geraldo and Lobo, four sites along the beach of balneário Santo Antônio, and one site at the upper part of the reservoir. The mouth of the Itaqueri river has been meso-eutrophic throughout the period, while the other evaluated sites have been oligotrophic. In spite of the favorable condition showed by the IET, the timing analyses of the data (based on studies done in the last 30 years) shows a clear and worrying change in this system original conditions, related mainly to the increase of nutrients and its consequences, indicating a clear process of eutrophication of the system, what may be associated to the usages and occupation of the river basin (homes wasting material, tourism, agriculture and cattle-raising). Relating to balneability, the main sites of fecal contamination in the reservoir are the tributaries entrances (in the Itaqueri river the contamination happens due to Itirapina\'s sewer system), while the reservoir body has been considered excellent throughout all the sampled period. The Água Branca river, as receptor of the Sewer treatment station and also the sewer from two Itirapina\'s prisons, is the most risking one from the water bodies evaluated, besides being the main contributor of nutrients and fecal coliforms to the Lobo reservoir through the Itaqueri river.

A presente pesquisa teve por objetivo analisar a composição e distribuição das espécies de macrófitas aquáticas no reservatório do Lobo (Broa), em quatro períodos do ano de 2007: março, maio, agosto e novembro. Para atender os objetivos propostos, variáveis limnológicas envolvendo os compartimentos água (pH, condutividade, temperatura, oxigênio dissolvido, clorofila, formas nitrogenadas e fosfatadas, silicato reativo e material em suspensão) e sedimento (granulometria, matéria orgânica, fósforo e nitrogênio) foram analisadas em 8 pontos de amostragem na região litorânea do reservatório. Simultaneamente, exemplares de macrófitas foram fotografados e coletados para identificação, buscando-se uma relação com as características limnológicas, hidrológicas (vazão e tempo de residência) e climatológicas (temperatura do ar, precipitação, vento e radiação). Os resultados da análise das variáveis físicas, químicas e biológicas dos diversos pontos de amostragem mostraram que existe uma diferenciação espacial e temporal no reservatório, verificando-se aumento do grau de trofia do mesmo em relação aos estudos anteriores. Quanto à composição e distribuição das macrófitas, estas se encontram mais concentradas na área alagada formada pelo barramento das águas do rio Itaqueri e ribeirão do Lobo, embora a maior riqueza de espécies tenha ocorrido no ribeirão do Lobo e córrego das Perdizes, sendo mais elevada em comparação com estudos anteriores. A distribuição espacial e temporal das macrófitas aquáticas apresenta relação com as características morfométricas, hidrodinâmicas e com o aporte de nutrientes pelos tributários, além das condições climatológicas, que inserem modificações na dinâmica do reservatório e, conseqüentemente, no estabelecimento e estruturação das comunidades. / The objective of this study was to examine the composition and distribution of aquatic macrophytes species in the Lobo reservoir (Broa) in four periods of the year 2007: March, May, August and November. To achieve the proposed objectives, limnological variables involving water (pH, conductivity, temperature, dissolved oxygen, chlorophyll, nitrogen and phosphated forms and reactive silicate) and sediment (grain, organic matter, phosphorus and nitrogen) compartments were analyzed at 8 sample stations in the littoral region of the reservoir. Meanwhile, samples of macrophytes were photographed and collected for identification, seeking a relationship with the limnological, hydrological (flow and length of residence time) and weather (air temperature, precipitation, wind and radiation) characteristics. The results of physical, chemical and biological variables of the various sample points showed that there is a spatial and temporal differentiation in the reservoir, verifying the increasing of the trophic levels in relation to previous studies. As to the composition and distribution of macrophytes, they are more concentrated in the flooded area formed by the barred waters of Itaqueri river and Lobo river, although the greatest wealth of species has occurred in Lobo river and Perdizes, being higher compared with earlier studies. The spatial and temporal distribution of aquatic macrophytes presents relationship with the morphometric and hydrodynamic characteristics and intake of nutrients by the rivers, in addition to climatic conditions, which inserts changes in the dynamics of the reservoir and, consequently, the establishment and structure of communities.

Com a rápida e desorganizada expansão humana o processo de eutrofização do complexo Billings está acelerado, afetando a dinâmica das comunidades aquáticas, em particular a fitoplanctônica. Uma das conseqüências da eutrofização são as florações de cianobactérias. Dentre os 150 gêneros de Cyanobacteria, cerca de 40 são produtores de toxinas (cianotoxinas). O reservatório Billings abrange áreas de 7 municípios e localiza-se a oeste da cidade de São Paulo, a 23º 47\' S e 46º e 40\' W, e a uma altitude de 746m. Seus usos incluem saneamento, geração de energia elétrica, lazer e abastecimento público. Este trabalho tem como objetivos principais: a) efetuar análises em duas coletas (época chuvosa e época seca) das varáveis físicas, químicas e biológicas da água em três pontos no complexo Billings e em três profundidades (superfície, meio e fundo) (Capítulo II), b) Identificar e quantificar a comunidade de cianobactérias em cada um dos pontos e relacionar a riqueza e abundância com a qualidade das águas (Capítulo II) e c) Analisar qualitativamente as cianobactérias presentes, com uso de técnicas de biologia molecular, incluindo polimorfismo genético (Capítulo III); d) Comparar os dados obtidos com as análises qualitativas tradicionais com os dados das análises moleculares, associados à diferentes amostragens e em épocas do ano distintas (Cápitulo IV). As concentrações de clorofila-a, fósforo total e oxigênio dissolvido não estão em conformidade com a resolução CONAMA nº357 para corpos hídricos classe II na maioria das amostras dos pontos analisados. As florações fitoplanctônicas, foram presentes neste estudo na represa Billings, apresentando altos biovolumes de cianobactérias (20568,5 µm3/mL no Ponto 1 em fevereiro de 2012) e de outros organismos fitoplanctônicos como os dinoflagelados (1000544 µm3/mL no Ponto 2 em fevereiro de 2012). Foram observadas florações do dinoflagelado Ceratium furcoides e da cianobactéria Microcystis aeruginosa em agosto e fevereiro, respectivamente, levando a preocupações com relação às condições tróficas do reservatório e aos potenciais prejuízos que estas espécies podem causar. O reservatório foi classificado entre supereutrófico e hipereutrófico, indicando forte degradação da qualidade das águas nos pontos amostrados. As análises moleculares não foram satisfatórias para a caracterização molecular das cianobactérias, pois as enzimas utilizadas para a digestão do DNA extraído e amplificado não encontraram o sítio para clivagem, sendo as adequações das reações e a utilização de outras enzimas as próximas etapas deste trabalho / With the rapid expansion and disorganized human process of eutrophication complex Billings is accelerated, affecting the dynamics of aquatic communities, particularly the phytoplankton. One consequence of eutrophication are cyanobacterial blooms. Among the 150 genera of Cyanobacteria, about 40 are producers of toxins (cyanotoxins). The Billings reservoir covers seven counties and areas located west of the city of São Paulo, at 23 º 47 \'S and 46 º 40\' W, at an altitude of 746m. Its uses include sanitation, power generation, recreation and public supply. This work has as main objectives: a) conduct analyzes in two samples (wet season and dry season) variables of the physical, chemical and biological characteristics of water at three points in the complex Billings and three depths (surface, middle and bottom) (Chapter II ), b) Identify and quantify the community of cyanobacteria in each of the points and relate the richness and abundance with water quality (Chapter II) and c) analyze qualitatively the cyanobacteria present, using molecular biology techniques, including genetic polymorphism (Chapter III); d) Compare the data obtained with the traditional qualitative analyzes with data from molecular analyzes, associated with different samples and different seasons (Chapter IV). The concentrations of chlorophyll-a, total phosphorus and dissolved oxygen are not in accordance with the Resolution CONAMA 357 for class II water bodies in most of the samples analyzed points. The phytoplankton blooms were present in this study in the Billings, showing high biovolumes cyanobacterial (20,568.5 μ m3/mL at Point 1 in February 2012) and other organisms as phytoplankton dinoflagellates (1000544 μ m3/mL at Point 2 in February 2012). Were observed blooms of the dinoflagellate Ceratium furcoides and the cyanobacterium Microcystis aeruginosa in August and February, respectively, leading to concerns in relation to trophic conditions of the reservoir and the potential damage that these species can cause. The reservoir was ranked among supereutrophic and hypertrophic, indicating strong degradation of water quality in the sampled points. Molecular analyzes were not satisfactory for the molecular characterization of cyanobacteria, as the enzymes used for digestion of DNA extracted and amplified not find the site for cleavage, and the adequacy of the reactions and the use of other enzymes the next steps of this work