A extensa rede de lagoas presente no litoral do Rio Grande do Sul constitui ecossistemas de grande diversidade ecológica. Esses corpos de água, também se caracterizam por apresentarem pequena profundidade, tornando-os sensíveis às mudanças naturais ou antrópicas. As interferências antrópicas podem acarretar em diversas modificações físicas e químicas, provocando a eutrofização dos corpos de água. Esse processo modifica as variáveis ambientais em diversos aspectos, influenciados principalmente pela concentração de nutrientes inorgânicos, penetração da luz, temperatura e pH da água, bem como a alteração da comunidade fitoplanctônica, especialmente as cianobactérias. Assim, o presente trabalho teve como objetivo avaliar a dinâmica da comunidade fitoplanctônica e da cianotoxina Microcistina e a relação com parâmetros físico-químicos em três lagoas localizadas no Município de Osório-RS. Os dados foram obtidos por meio de amostragens realizadas sazonalmente em quatro pontos amostrais distribuídos em três lagoas (Marcelino, Peixoto e Pinguela). As amostras foram analisadas quanto aos parâmetros físico-químicos, a densidade fitoplanctônica e a concentração de microcistina. Com base nos dados obtidos foram elaboradas PCA’s considerando os parâmetros fisico-químicos e a relação com o fitoplâncton, bem como avaliada a relação entre as variáveis utilizando-se a correlação de Spearman. Os resultados mostram um processo de eutrofização nas lagoas estudadas, onde 67,6% da variabilidade ambiental total nos pontos amostrais está relacionada diretamente à clorofila-a, DBO5, N-NH4, P-total, condutividade e inversamente à transparência de Secchi. Quanto à dinâmica da comunidade fitoplanctônica conforme os parâmetros físico-químicos, a análise demonstrou efeito antagônico das variáveis com carga positiva (N-NH4, DBO5, P-total, clorofila-a, condutividade, densidade de Cyanophyceae, Chlorophyceae e Bacillariophyceae) versus as de carga negativa (transparência de Secchi). A concentração de microcistina variou de 0,02μg/L a 0,51 μg/L, permanecendo abaixo do limite permitido pela legislação brasileira para água potável. Contudo, a baixa concentração não assegura que os corpos hídricos estudados estejam livres de cianotoxinas, uma vez que não foram analisadas outras toxinas, como cilindrospermopsina, saxitoxina e anatoxina-a, abordadas na legislação vigente e produzidas por espécies pertencentes ao mesmo grupo taxonômico. Com os resultados verifica-se um nítido gradiente de eutrofização entre as lagoas, que se inicia na Marcelino, que é o corpo receptor do efluente doméstico proveniente de Osório, e segue em direção ao norte. Esse gradiente influencia diretamente a comunidade fitoplanctônica e favorece condições e recursos para o crescimento de grupos relacionados a elevada eutrofização, como as classes Chlorophyceae, Cyanophyceae e Bacillariophyceae. Apesar da baixa concentração da cianotoxina microcistina, o elevado número de cianobactérias encontradas durante a amostragem sugere que outras cianotoxinas possam estar presentes em altas concentrações nas lagoas. A elevada densidade de indivíduos do gênero Dolichospermum evidencia a necessidade de um constante monitoramento das lagoas, uma vez que a presença deste grupo taxonômico acarreta a possibilidade da existência de diversas cianotoxinas causadoras de efeitos nocivos à população humana, além de impactar os organismos aquáticos e a vida selvagem de diversas formas. / Petróleo Brasileiro, PETROBRAS

A compreensão da dinâmica hídrica e das relações ecológicas em estudos limnológicos inclui, imprescindivelmente, a morfologia do corpo de água. O conhecimento científico dos parâmetros morfométricos é fundamental não somente para medidas e quantificações, mas também para o entendimento dos processos internos que influenciam a dinâmica dos nutrientes e a distribuição das comunidades biológicas. A planície costeira do Rio Grande do Sul foi formada por processos de erosão e deposição durante eventos marinhos de transgressão e regressão, associados à erosão fluvial e eólica durante o Quaternário. Durante o Pleistoceno e Holoceno foram estruturados quatro sistemas de depósito, chamados laguna-barreira, compreendendo grande diversidade de ecossistemas úmidos, dentre os quais as lagoas ao longo da costa do Oceano Atlântico, em sua maioria contendo água doce. Devido a sua gênese, essas lagoas são rasas, com profundidade relativa inferior a 2% e alcançam profundidade máxima de 11 metros no litoral médio do Rio Grande do Sul. O presente estudo teve como objetivo caracterizar morfologicamente as lagoas do município de Osório, Rio Grande do Sul, Brasil. Devido às características regionais de toponímia e segmentação, algumas lagoas puderam ser avaliadas como um ou mais corpos de água, resultando na caracterização de 20 corpos de água a partir dos 16 nomes oficiais atribuídos às lagoas. Os levantamentos batimétricos foram realizados entre os anos de 2013 e 2015, com o uso de ecobatímetro acoplado de GPS e aplicação de sensoriamento remoto e Sistemas de Informações Geográficas (SIG). Como resultados foram produzidos um artigo submetido à Revista Brasileira de Recursos Hídricos e um capítulo de livro na obra Atlas Sociombiental do Município de Osório. No artigo intitulado “Morphological characterization of thirteen lakes in Osório, northern coastal plain of Rio Grande do Sul, Brazil” foram caracterizadas morfologicamente 13 lagoas no município de Osório, Rio Grande do Sul, Brasil. A análise de Cluster distinguiu quatro grupos morfológicos, confirmados pela Análise Discriminante. A análise de componentes principais identificou o primeiro componente com carga positiva para parâmetros de tamanho e carga negativa para a profundidade relativa, enquanto o segundo componente apresentou carga positiva para as profundidades máxima e profundidade média e carga negativa para o desenvolvimento do perímetro e o desenvolvimento do volume. Os parâmetros de tamanho mostraram ser, portanto, mais importantes na classificação das lagoas do que os parâmetros de profundidade. A baixa profundidade das lagoas estudadas (profundidade máxima = 4,6 m, maior profundidade média = 2,2 m) é elemento fundamental na gestão dos recursos hídricos, uma vez que o pequeno volume e tamanho tornam as lagoas rasas mais suscetíveis a processos de eutrofização. No capítulo intitulado “Morfologia”, as lagoas são apresentadas com mapa batimétrico, imagem aérea, parâmetros morfométricos e descrição das principais características de cada lagoa. O capítulo é apresentado de forma didática e com linguagem acessível, de forma a abranger um público amplo. Dados morfológicos são essenciais para a compreensão ecológica das lagoas, especialmente se associados a análises de transparência, turbidez, distribuição vertical de nutrientes e oxigênio e aplicação de índices tróficos, bem como são subsídio para a gestão dos recursos hídricos. / The understanding of water dynamics and ecological relations in limnological studies necessarily includes the morphology of the water body. The scientific knowledge of morphometric parameters is fundamental not only for measurements and quantification, but also for the understanding of internal processes that influence nutrient dynamics and the biological communities distribution. The coastal plain of Rio Grande do Sul was formed by erosion and deposition processes during marine transgression and regression process, associated with fluvial and wind erosion during the Quaternary. During the Pleistocene and Holocene, four depositional systems, called barrier-lagoon, were settled comprising a great diversity of humid ecosystems, among them the lakes along the coast of the Atlantic Ocean, mostly containing fresh water. Due to their genesis, the lakes are shallow with relative depth less than 2% and maximum depth of 11 meters in the middle coast of Rio Grande do Sul. The study aimed to morphologically characterize the lakes of Osório, Rio Grande do Sul, Brazil. Due to the regional characteristics of toponymy and segmentation some lakes could be evaluated as one or more water bodies, resulting in the characterization of 20 water bodies from the 16 official names attributed to the lakes. Bathymetric surveys were conducted between the years 2013 and 2015, based on echo sounder coupled with GPS and application of remote sensing and GIS. As results were produced an article submitted to the Brazilian Journal of Water Resources and a chapter in book titled “Atlas Socioambiental do Município de Osório”. In the article titled "Morphological characterization of thirteen lakes in Osório, northern coastal plain of Rio Grande do Sul, Brazil" were morphologically characterized 13 lakes in Osório, Rio Grande do Sul, Brazil. Cluster analysis distinguished four morphological groups, confirmed by Discriminant Analysis. Principal component analysis identified the first component positively charged with parameters of size and negatively charged with relative depth, while the second component was positively charged with maximum and average depths and negatively charged with perimeter development and volume development. Therefore, size parameters were more important for the lakes classification than depth parameters. The coastal lakes shallowness (maximum depth = 4.6 m, largest average depth = 2.2 m) is a fundamental element for water resources management, since their low volume and small size make them more susceptible to eutrophication processes. In the chapter titled "Morfologia", the lakes are presented with bathymetric map, aerial photo, morphometric parameters and a description of the main characteristics for each lake. The chapter is presented in a didactic and accessible language in order to reach a wide public. Morphological data are essential ecological understanding of lakes, especially if associated with analyzes of transparency, turbidity, vertical distribution of nutrients and oxygen and application of trophic indexes, as well as being a subsidy for the water resources management.

Waste stabilization ponds (WSPs) are one of the most prevalent types of domestic wastewater treatment technologies employed worldwide, and global stressors such as urbanization, population growth, climate change, and water scarcity have increased the demand for reusing treated wastewater. The safe reuse of treated wastewater in agriculture can ease water scarcity, aid in food production, and reduce environmental degradation from the discharge of wastewater effluent to surface waters. The ability to predict virus concentrations in wastewater effluent is an important criterion for determining whether wastewater is suitable for discharge to the environment or for reuse in agriculture. However, many uncertainties remain about virus removal efficiency in WSPs and there is currently no mechanistic or empirical model that reliably predicts virus removal in WSPs. The overall objective of this thesis research was to model the extent of virus removal in individual waste stabilization ponds to support the reuse of wastewater. A literature review was used to create a database of estimated apparent virus removal rate coefficients (Kv,app) in three different WSP types (anaerobic, facultative, and maturation ponds). The database consisted of 249 paired influent and effluent concentrations of enteric viruses or bacteriophages from 44 unique WSP systems, comprised of 112 individual WSPs from 19 different countries. Apparent virus removal rate coefficients (Kv,app) were calculated for each individual WSP using the following three mathematical models from reactor theory: complete mix, plug flow, and dispersed flow. Pearson’s correlation analysis was used to determine correlations between Kv,app values and the following design, operational, and environmental parameters: solar radiation, air temperature, pond depth, hydraulic retention time (HRT), and virus loading rates. The median Kv,app values were greater for anaerobic ponds than for facultative and maturation ponds; however, Kv,app values in facultative and maturation ponds had more significant correlations with design, operational, and environmental parameters. Additionally, Kv,app values appear to be significantly different for various types of enteric viruses and bacteriophages. Alternative multiple linear regression equations were developed to predict Kv,app values using the design, operational, and environmental parameters as explanatory variables. Analysis of variance (ANOVA) tests were used to select the most appropriate multiple linear regression equations with the least amount of explanatory variables. The most appropriate plug flow and dispersed flow multiple linear regression equations for predicting Kv,app values included air temperature and HRT as explanatory variables. The results indicate that the plug flow regression equation was able to better predict Kv,app values (R2 = 0.38) than the dispersed flow regression equation (R2 = 0.24) in facultative and maturation ponds based on the dataset. However, both the dispersed flow and plug flow models had R2 values of approximately 0.84 when they were used to predict effluent virus concentrations in facultative and maturation ponds based on the dataset. According to this research, the plug flow regression equation is recommended for predicting apparent virus removal rate coefficients in WSPs. However, a multi-model approach that utilizes both the plug flow and dispersed flow models may yield a more robust mathematical model that can improve WSP design, reliably predict virus removal in WSPs, and ultimately be used to support wastewater reuse.

Magister Scientiae - MSc / The study shows conclusively that brine composition and concentration is highly variable at these South African power utilities and processes such as RO, contact with ash and CO2 ingress can have an impact upon the overall brine quality. Aq.QA was found to be a more accurate tool for classifying waters according to dominant ions than Stiff diagrams but Stiff diagrams still have the superior advantage of being a mapping tool to easily identify samples of similar composition as well as quickly identify what has been added or what has been removed from a water stream. Chemical speciation could identify effluent streams where CO2 dissolution had taken place. / South Africa

No description available.

Made available in DSpace on 2017-07-24T19:37:59Z (GMT). No. of bitstreams: 1 Joelma Adriane Wiesinieski.pdf: 2892011 bytes, checksum: cda8a9b8b1f38d58c117f0c13269172b (MD5) Previous issue date: 2009-03-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The final disposition place of trash at Ponta Grossa city started out in 1969, in an appearance of garbage in the Botuquara’s region, and became the controlled garbage earthwork in 2001. The leach forming in this kind of landfill is, currently, the purpose of many studies principally in the vehicular of diseases and damages to the environment. The aim in this paper is to evaluate the characteristics of the sediments of the decantation lagoons that receive the percolado from the “Aterro Controlado do Botuquara” and of the soil next to the place where the last lagoon liberates to the environment this percolado, in order to evaluate if it is occurring retention of weighty metals, how is this retention, and also if the near area is receiving these metallic species. It were done accomplishing analyses of pH, OM, organic carbon, total nitrogen, C:N relation, CEC, K+, phosphates and sand contents, clay and silt to the sediments, as well as determined the concentrations of Cu, Cr, Fe, Mn, Ni, Ag, Pb and Zn the carbonates, organic substance, oxides of iron and manganese and the easily exchangeable ones in the samples of the sediments.The results show that the sediment possesss high texts of Mn, Fe, Cr, Ag, Ni, Cu, in some fractions of the collection points, mainly in the total fraction. The treatment lagoons are not being efficient, because of the total metal found in the landfill´s leach, when it is launched in the water will be able to modify its properties and to compromise its quality. / A disposição final do lixo da cidade de Ponta Grossa-Pr teve início em 1969, com a criação de um lixão na região do Botuquara, que em 2001 passa a aterro controlado. A formação de lixiviado neste tipo de aterro é atualmente, objetivo de vários estudos, principalmente no que se refere à veiculação de doenças e aos danos ambientais. Este estudo tem por objetivo avaliar as características dos sedimentos das lagoas de decantação que recebem o percolado do Aterro Controlado do Botuquara, e do solo próximo ao local onde a ultima lagoa libera para o meio ambiente o percolado, a fim de avaliar se está ocorrendo à retenção dos metais pesados, como é esta retenção, e também, se área próxima está recebendo estas espécies metálicas. Foram realizadas análises de pH, carbono orgânico, matéria orgânica, capacidade de troca catiônica, nitrogênio total, relação carbono: nitrogênio, potássio, fosfato, teor de argila, areia e silte , assim como determinadas as concentrações de Cu, Cr, Fe, Mn, Ni, Ag, Pb e Zn ligados a carbonatos, matéria orgânica, óxidos de ferro e manganês e os facilmente trocáveis nas amostras dos sedimentos.Os resultados mostram que o sedimento possui teores elevados de Mn, Fe, Cr, Ag, Ni, Cu, , em algumas frações dos pontos de coleta, principalmente na fração total. As lagoas de tratamento não estão sendo eficientes, para retenção total de metais presentes no lixiviado do aterro, se este for lançado em corpos de águas, poderá alterar suas propriedades e comprometer sua qualidade.

De nombreuses espèces de poissons marins côtiers à forte valeur économique ont un cycle de vie complexe impliquant des migrations saisonnières entre l'environnement marin et les habitats côtiers. Une meilleure compréhension de leur cycle de vie, en particulier l'identification de leurs nourriceries clés, est vitale pour la gestion durable des stocks de poissons exploités. Cette étude évalue la fonction de nourricerie des lagunes côtières du Golfe du Lion (Méditerranée NO) pour la daurade royale, Sparus aurata, une espèce d'intérêt commercial, dont les juvéniles colonisent ces habitats chaque année pendant leur premier été de vie. La qualité en tant que nourriceries de quatre lagunes aux conditions environnementales contrastées a été estimée par des mesures de la condition (indices de Fulton et TAG:ST) et du taux de croissance (par otolithométrie) des juvéniles. Les résultats montrent une condition et une croissance des juvéniles plus importantes dans les deux lagunes les plus dessalées et peu profondes (Bages-Sigean et Mauguio) que dans les deux lagunes profondes aux salinités proches de celle de la mer (Salses-Leucate et Thau). Les différences spatiales, stables dans le temps, de signatures élémentaires des otolithes ont permis de valider ces dernières comme tag naturel pour discriminer les habitats des juvéniles de daurade royale. Ainsi, l'identification a posteriori des nourriceries colonisées au stade juvénile chez des adultes pêchés le long de la côte du Golfe du Lion a pu être réalisée. Les estimations de la contribution relative des habitats des juvéniles au stock d'adultes (selon la contribution absolue ou la contribution par unité de surface) révèlent l'importance globale des lagunes pour le maintien des populations. Les lagunes les plus dessalées ont été identifiées comme les meilleures nourriceries de la zone d'étude. Le rôle important de la lagune de Thau pour le maintien des stocks de poissons a également été mis en évidence. Les résultats dans leur ensemble montrent une certaine convergence entre les estimations d'exports potentiel et réel des habitats des juvéniles. Les conclusions de cette étude sont primordiales pour la gestion et la protection des habitats clés des juvéniles ainsi que les ressources exploitées qui en dépendent. / Many coastal marine species of major socio-economic importance exhibited complex life histories include seasonal migrations between offshore marine environments and inshore coastal habitats. An adequate scientific understanding of their life cycle and, in particular the identification of the most significant juvenile nursery grounds are urgently needed for the sustainable management of fish stocks. This present study investigated the nursery function of coastal lagoons in the Gulf of Lions (NW Mediterranean) for a valuable fish species, the gilthead sea bream Sparus aurata, whose juveniles colonize these habitats each year for feeding and growing over their critical first summer of life. Habitat quality of four contrasted lagoons was measured with body condition (Fulton and muscle TAG/ST indices) and otolith growth rate of juveniles. Results showed better condition and higher growth rates in juveniles inhabiting the two shallow and brackish lagoons (Bages-Sigean, Mauguio) compared to the two deeper and more saline lagoons (Salses-Leucate and Thau). Otolith elemental signatures were temporally validated as natural tags to discriminate among juvenile habitats, allowing the retrospective identification of juvenile origin of S. aurata adults captured along the Gulf of Lions coastline. The estimations of relative contributions of juvenile habitats to adult stocks revealed the overall significance of lagoons for the maintenance of population. While, brackish lagoons were identified as the major contributors and best nursery habitats in the area, the importance of Thau lagoon to sustain fish stocks was also highlighted. Combined results of this research revealed some agreement between potential and effective export estimates from juvenile habitats. Information derived from this study is highly valuable for the sustainable management and protection of juvenile habitats, and the fishery resources that depend on them.

O modo de vida da humanidade demanda novas alternativas às fontes energéticas fósseis, precisa garantir a produção de alimentos e energia para uma população que já ultrapassa 7 bilhões, além de ter de gerir seus Resíduos Sólidos (RS) e efluentes (esgoto), em que grande parte dos primeiros, são enterrados em aterros sanitários e/ou lixões, gerando problemas sanitários e ambientais e desperdício de nutrientes para a agricultura. Parte dessa tripla solução energética/alimentar/sanitária pode vir dos recursos contidos nos Resíduos Biodegradáveis (RB), ou como dito na Lei Brasileira Nº 12.305 - "Resíduos Orgânicos" (RO), que podem ser biometanizados para gerar gás combustível, metano, CH4 e/ou gás hidrogênio, H2 e posterior uso do sólido e líquido resultante na forma de substrato para a agricultura, ou processos fotossintéticos aquáticos mediados por microalgas e macrófitas. Paralelamente ao tratamento anaeróbio, se os RO forem tratados aerobicamente, via compostagem e/ou vermicompostagem, não se gera nenhum gás combustível que possa ser usado em outro momento e local, apenas calor. Diante desse quadro, se propõe uma alternativa para o tratamento de resíduos biodegradáveis e efluentes domésticos em zonas rurais e periurbanas, por meio da proposta de uma pequena central de tratamento de resíduos orgânicos composta por uma lagoa facultativa com geração e coleta de biogás, associada com um sistema de hidrolisação de resíduos sólidos orgânicos e de tratamento de biogás, havendo a separação do CO2 em fase aquosa para alimentação de carbono e alcalinidade ao sistema de bacia de fotossíntese de microalgas e macrófitas do gênero lemna. Foram realizados balanços de água, nutrientes, eletricidade e monetário para aferir a consistência teórica para futura aplicação dos projetos e suprir as três demandas/soluções citadas. Foi possível aferir que o custo do metro cúbico de gás metano gerado ficou em torno de 0,5- 4 R$.m-3 de gás metano. Foi possível propor um projeto para se caminhar no sentido de poder dar base a trabalhos futuros, que desenvolvam métodos inovadores de gestão de resíduos para serem aplicados no Brasil, com o fim de descentralizadamente adequar os municípios ao PNRS, ao mesmo tempo em que se cria na nação o conceito de biorrefinaria, integrando-a ao saneamento básico e ambiente, em prol da soberania individual energética/alimentar/hidrológica dos brasileiros. / People's way of living demands alternatives to fossil energy, needs to produce food for a population that has already reached more than seven billion and has to deal with waste generation, namely solid wastes and sewage, while most of the first are buried in landfills or even dumped, generating sanitary and environmental problems while wasting nutrients for agriculture. Part of that triple energy/food/sanitation solution can come from biodegradable wastes, or like the way is said on Brazilian Law Nº12.305 - &#34Organic Wastes", that can be converted into biogas, methane or hydrogen gas, and subsequent use of solid and liquid digestate for agriculture, or aquatic photosynthetic processes mediated by microalgae and macrophytes. Paralel to anaerobic treatment, if organic wastes are aerobically treated, by compoting and/or wormcomposting, not any renewable gas will be generated for later use, it just generates heat. By this cenario, this master thesis propose and evaluate, technological alternatives for biodegradable waste and wastewaters in cities vicinities and/or rural areas nearby urban areas by proposing a small biodegradable waste treatment plant composed of a facultative lagoon with biogas generation on its bottom, associated with a system of solid waste hydrolysis built inside a shed which realizes biogas treatment as well, with carbon dioxide gas liquid separation for carbon and alkalinity feeding the multispecies photosynthesis bowl, half consisted of dispersed microalgae and the other half composed of macrophyte of lemna genera. Water, nutrients, electricity and money balances were done in order assess the theoretical consistency for future development of those projects and quench the three cited demands/solutions. It was possible to affirm that the cost of a cubic meter of methane gás is around 0,5 – 4 R$.m-3. Projects were proposed, that can develop innovative methods for biodegradable waste management to be done in Brazil, with the ultimate goal of adequating towns to the National Solid Waste Policy (Política Nacional de Resíduos Sólidos – PNRS in portuguese) in a decentralized manner, meanwhile it helps to create alog the nation the biorefinery concept, integrating itself into waterworks, sanitation and the environment, feeding individuals energy, food and hydrological sovereignity of brazilians.

Το πρόβλημα της αυξημένης σύλληψης υπομεγεθών ατόμων τσιπούρας (Sparus aurata, Linnaeus 1758) στις ιχθυοσυλληπτικές εγκαταστάσεις της λιμνοθάλασσας Μεσολογγίου-Αιτωλικού τις τελευταίες δεκαετίες έχει αποκτήσει σοβαρές διαστάσεις. Το φαινόμενο αυτό εκτός του ότι συνιστά περιβαλλοντική απειλή έχει επιφέρει σημαντική μείωση της εμπορικής αξίας του αλιεύματος με αποτέλεσμα τη συρρίκνωση του εισοδήματος των αλιέων. Η παρούσα εργασία μελετά την επιλεκτικότητα νέων τροποποιημένων ιχθυοπαγίδων που έχουν εγκατασταθεί στη λιμνοθάλασσα στο πλαίσιο μιας πρωτοβουλίας για την αντιμετώπιση του συγκεκριμένου προβλήματος. Η παρακολούθηση αυτής της πρωτοβουλίας έδειξε ότι οι νέες ιχθυοπαγίδες συμβάλλουν στη διαφυγή των υπομεγεθών ψαριών, οπότε και στη μείωση των ποσοτήτων των απορριπτόμενων ψαριών διασφαλίζοντας έτσι τη βιωσιμότητα του ιχθυοπληθυσμού. Επίσης, αυξάνονται τα έσοδα της αλιευτικής εκμετάλλευσης και βελτιώνεται η καθημερινότητα των αλιέων δεδομένου ότι δε μεσολαβεί το στάδιο του διαχωρισμού των μη εμπορεύσιμων από τα εμπορεύσιμα ψάρια. Οι διαφυγές των ψαριών από τις ιχθυοπαγίδες φάνηκε να επηρεάζονται από την αφθονία του αλιεύματος και πιο συγκεκριμένα σε περιπτώσεις μεγάλης αφθονίας παρατηρήθηκε να δυσχεραίνεται η διαφυγή των υπομεγεθών ψαριών από τις ιχθυοπαγίδες. Ενδεχομένως, αυτό να δημιουργεί την ανάγκη επέκτασης της τροποποιημένης επιφάνειας των ιχθυοπαγίδων. Η παρούσα εργασία αποτελεί πηγή σημαντικών πληροφοριών στη λήψη μέτρων με στόχο τη βελτίωση του προτύπου της αλιευτικής εκμετάλλευσης της λιμνοθάλασσας. / The problem of increased capture of undersized individuals of gilthead seabream (Sparus aurata, Linnaeus, 1758) at the Messolonghi - Etoliko lagoon fish traps, the last decades has become serious. This phenomenon apart from the ecological threat has decreased the commercial value of the catch thus leading to a reduction of the fishermen income. The present study investigates the selectivity of new fish traps installed in the lagoon in order to deal with this problem. It was found that modified traps contribute to the escapement of undersized individuals thus decreasing the discards as well as ensuring the sustainability of fish population. Furthermore, new traps exploitation leads to an increase of the income. Also, there is no need to sort undersized fish from the catch thus improving the daily lives of the fishermen. Fish escapement was found to be affected by the abundance of fish catch. In more details, high abundance was observed to make fish escapement difficult. Perhaps, this highlights the need of modified area extension. The present study reflects a source of useful information to take into consideration for the improvement of the lagoon fishery exploitation.

Στην παρούσα διδακτορική διατριβή μελετήθηκαν οι λιμνοθάλασσες της Δυτικής Ελλάδας Ροδιά, Τσουκαλιό και Λογαρού του Αμβρακικού κόλπου, η λιμνοθάλασσα Κλείσοβα του συμπλέγματος λιμνοθαλασσών Μεσολογγίου-Αιτωλικού, η λιμνοθάλασσα του Αράξου και η λιμνοθάλασσα του Καϊάφα με σκοπό να αξιολογηθεί η οικολογική τους κατάσταση με τη χρήση υδρόβιων μακροφύτων ως ειδών δεικτών. Τα αποτελέσματα της διατριβής παρουσιάζονται σε τέσσερα μέρη. Στο πρώτο μέρος γίνεται διάκριση των λιμνοθαλασσών της Δυτικής Ελλάδας σε τύπους με βάση τα κύρια αβιοτικά και γεωμορφολογικά χαρακτηριστικά τους. Στο δεύτερο μέρος διερευνώνται οι εποχικές και χωρικές διακυμάνσεις των αβιοτικών παραμέτρων που μετρήθηκαν σε κάθε τύπο λιμνοθάλασσας από την άνοιξη του 2005 έως το φθινόπωρο του 2007. Στο τρίτο μέρος γίνεται διάκριση των υδρόβιων μακροφύτων των λιμνοθαλασσών της Δυτικής Ελλάδας σε συναθροίσεις και διερευνώνται οι εποχικές και διαχρονικές τους μεταβολές σε κάθε τύπο λιμνοθάλασσας. Τέλος, στο τέταρτο μέρος της διδακτορικής διατριβής εκτιμήθηκε η οικολογική κατάσταση κάθε τύπου λιμνοθάλασσας με τη χρήση έξι διαφορετικών δεικτών που βασίζονται τόσο σε αβιοτικά (TSI-Chl-a, TSI-TP, TRIX) και βιοτικά κριτήρια (EEI, E-MaQI) ή συνδυασμό και των δύο (TWQI). Στη Μεσόγειο διακρίθηκαν συνολικά πέντε τύποι λιμνοθαλασσών που διαφέρουν σημαντικά μεταξύ τους ως προς το μέγεθος και την αλατότητα. Οι λιμνοθάλασσες της Δυτικής Ελλάδας ανήκουν στους τέσσερις από τους πέντε τύπους. Οι τιμές των αβιοτικών παραμέτρων που μετρήθηκαν κατά τη διάρκεια των περιόδων παρακολούθησης (άνοιξη 2005-φθινόπωρο 2007), υποδεικνύουν τη χωρική και χρονική διακύμανση των χαρακτηριστικών της στήλης του νερού στους τέσσερις τύπους λιμνοθαλασσών της Δυτικής Ελλάδας, με σημαντικότερες μεταβολές να παρατηρούνται κυρίως την άνοιξη και το καλοκαίρι. Στην παρούσα διδακτορική διατριβή για πρώτη φορά γίνεται συστηματική καταγραφή και παρακολούθηση της υδρόβιας βλάστησης στις λιμνοθάλασσες της Δυτικής Ελλάδας. Συνολικά συλλέχθηκαν και αναγνωρίστηκαν 40 είδη υδρόβιων μακροφύτων που σχηματίζουν πέντε διαφορετικές συναθροίσεις μακροφύτων. Τα αγγειόσπερμα είδη Zostera noltii, Ruppia cirrhosa, Cymodocea nodosa, Potamogeton pectinatus καθώς και τα χαρόφυτα Lamprothamnium papulosum και Chara hispida f. corfuensis αποτελούν τα κυρίαρχα είδη στους τύπους λιμνοθαλασσών της Δυτικής Ελλάδας και είναι εκείνα τα οποία συμβάλλουν σημαντικά στην ανομοιότητα (ANOSIM) των συναθροίσεων μεταξύ των τύπων λιμνοθαλασσών. Οι δείκτες εκτίμησης της τροφικής κατάστασης των μεταβατικών οικοσυστημάτων που χρησιμοποιούνται μέχρι σήμερα έχουν σχεδιαστεί είτε για λίμνες είτε για παράκτια ύδατα και η επιλογή του καταλληλότερου αποτελεί πρόκληση για την επιστημονική κοινότητα. Η εφαρμογή αβιοτικών δεικτών στις λιμνοθάλασσες της Δυτικής Ελλάδας κατατάσσει την τροφική κατάσταση των λιμνοθαλασσών κυμαίνεται από ολιγοτροφική έως υπερτροφική. Επιπλέον, στην παρούσα διδακτορική διατριβή, η εφαρμογή βιοτικών δεικτών που στηρίζονταν στην υδρόβια βλάστηση παρουσίασε δυσκολίες και περιορισμούς λόγω των διαφορετικών ειδών υδρόβιων μακροφύτων που απαντώνται στις λιμνοθάλασσες της Δυτικής Ελλάδας. Ο δείκτης E-MaQI μπόρεσε να εφαρμοστεί μόνο σε δύο (Κλείσοβα, Άραξος) από τις έξι λιμνοθάλασσες λόγω περιορισμένου αριθμού ειδών, ενώ ο δείκτης ΕΕΙ-c δεν εφαρμόστηκε στη λιμνοθάλασσα του Καϊάφα λόγω έλλειψης κατάταξης του είδους Chara hispida f. corfuensis σε ομάδα οικολογικής κατάστασης. Παρόλα αυτά, στις περιοχές όπου εφαρμόστηκαν οι παραπάνω δείκτες η οικολογική κατάσταση των λιμνοθαλασσών κυμαίνονταν από φτωχή έως άριστη. Στην παρούσα διδακτορική διατριβή ελέγχθηκε και βαθμονομήθηκε ο πολυμετρικός δείκτης TWQI στους τέσσερις τύπους λιμνοθαλασσών της Δυτικής Ελλάδας και συγκρίθηκε με άλλα έξι διαφορετικά μεταβατικά οικοσυστήματα της Μεσογείου. Από τα αποτελέσματα προκύπτει ότι η εφαρμογή του πολυμετρικού δείκτη TWQI είναι καταλληλότερη για τα μεταβατικά οικοσυστήματα. Τα αποτελέσματα της παρούσας διδακτορικής διατριβής μπορούν να αποτελέσουν σημαντικό εργαλείο στην κατανόηση των σχέσεων που αναπτύσσονται μεταξύ των φυσικοχημικών παραμέτρων και των υδρόβιων μακροφύτων ως μέρους των δομικών στοιχείων των λιμνοθαλασσών και τα συμπεράσματά της μπορούν να συγκριθούν με αντίστοιχα των λιμνοθαλασσών της Μεσογείου. / In the current thesis they were monitored six coastal lagoons positioned at the Western coast of Greece: Rodia, Tsoukalio and Logarou lagoons belonging to the Amvrakikos Gulf lagoonal complex, as well as Kleisova which belong to the Messolonghi-Aitoliko lagoonal complex, Araxos and Kaiafas lagoons in order to assess their ecological status using aquatic macrophytes as indicator species. The results of this study are presented in four parts. Into the first part coastal lagoons were classified into lagoon types according to their main abiotic and geomorphological characteristics. The second part explores the seasonal and spatial variations of abiotic parameters measured in each lagoon type from spring 2005 to autumn 2007. Additionally, the third part distinguishes the aquatic macrophytes of Western Greece coastal lagoons in assemblages and investigated the seasonal and temporal changes of them in each lagoon type. Finally, the fourth part of the thesis assessed the trophic status of each lagoon using six different indicators based on both abiotic (TSI-Chl-a, TSI-TP, TRIX) and biotic criteria (EEI-c, E-MaQI) or combination of both (TWQI). In the Mediterranean region coastal lagoons were totally distinguished into five lagoons types which differ significantly in size and salinity. Coastal lagoons of Western Greece belong only to four of them. The principal component analysis applied separately to the lagoons of Western Greece verify the above results and except from size and salinity, considers that the average depth, the freshwater inflow, the length and width of the barrier and the degree of confinement contribute significantly to their differentiation. The values of abiotic parameters measured during the monitoring periods, indicate the spatial and temporal variation of water quality characteristics at four lagoon types of Western Greece, with significant changes mainly occur in spring and summer. Coastal lagoons with high degree of confinement (Type I – Rodia) showed high nitrate concentrations and lower salinity values, unlike lagoon Types II and III (Tsoukalio, Logarou, Kleisova, Araxos) that are exposed to higher seawater influence. In all studied lagoons of Western Greece, the mean concentration values of Chl-a were low, although nutrient concentrations were high, indicating ongoing eutrophication phenomena. The current thesis constitutes the first systematic approach of monitoring the submerged aquatic vegetation of coastal lagoons in Western Greece. They were totally collected and identified 40 submerged aquatic macrophyte species which forming five different macrophytic assemblages. The angiosperm species of Zostera noltii, Ruppia cirrhosa, Cymodocea nodosa, Potamogeton pectinatus, as well as, the charophytes Lamprothamnium papulosum and Chara hispida f. corfuensis are the dominant species of coastal lagoons in Western Greece. These species contribute significantly to the dissimilarity (ANOSIM) of macrophytic assemblages between lagoon types. The presence of opportunistic species of the genus Ulva and Cladophora, as well as epiphytic species of genus Chondria or Ceramium were more pronounced in spring and summer. During the monitoring period they were recorded significant changes in salinity values in Rodia lagoon resulting thus to the decrease of mean abundance of the angiosperm species Zostera noltii which was replaced by Ruppia cirrhosa. The results of Redundancy Analysis (RDA) showed that abiotic parameters such as depth, salinity, dissolved oxygen, pH and concentrations of Chl-a and total inorganic nitrogen affect the composition of macrophytic assemblages. The calculation of diversity indices in coastal lagoons of Western Greece showed statistically significant differences between seasons and sampling stations. Lagoon types that are more influenced by seawater intrusion such as Types II and III showed higher number of species and higher Shannon index values with respect to lagoon Types I and IV. In this thesis the application of biotic indices based on submerged aquatic vegetation presented difficulties and limitations due to the different species of aquatic macrophytes found in coastal lagoons of Western Greece. The index E-MaQI could be implemented in only two (Kleisova, Araxos) of the six lagoons due to the limited number of species, while the index EEI-c could not be applied in Kaiafas lagoon due to the lack of classification of species Potamogeton pectinatus in an ecological status group. However, into the areas in which both indices applied yielded different results ranging from poor to high ecological condition. The multimetric index TWQI was tested and calibrated in four different lagoon types of Western Greece and compared with other Mediterranean transitional water ecosystems. The results showed that the application of TWQI is appropriate for transitional ecosystems. The index is simple to use and is less sensitive to changes in Chl-a and nutrients that derived from nutrient inputs due to anthropogenic activities. The results of this thesis could be considered an important tool for understanding the relationships between physicochemical parameters and aquatic macrophytes, as part of the structural elements of the lagoons, while the findings could be compared with other lagoons of the Mediterranean Sea.