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Irgarol 1051 is a common antifoulant toxic to certain marine organisms. Submerged aquatic vegetation (SAV) are exposed to this herbicide when it leaches into the marine environment from painted structures, making SAVs ideal candidates to function as sentinel indicator of contamination. In the initial stage of this study, Coconut Grove and Key Largo Harbor were assessed for environmental exposure to Irgarol. Water, sediment and SAVs were collected, the latter two subject to automated solid phase extraction, and all samples analyzed by GC/MS-SIM for Irgarol and its metabolite, M1. Of the vegetation analyzed, Halodule and Syringodium had the highest capacity to bioaccumulate Irgarol and M1. The root system and leaf contributed negligibly and significantly, respectively, to Irgarol uptake. In the final stage, a transplant between Coconut Grove and Chicken Key showed that the biota Thalassia and Halodule were able to uptake and depurate Irgarol, respectively, over a period of 30 days.

This thesis resulted from an examination of Lake Worth plankton in comparison to plankton found in similar bodies of water throughout the United States.

Yes / Aquatic vegetation can significantly affect flow structure, sediment transport, bed scour and water quality in rivers, lakes, reservoirs and open channels. In this study, the lattice Boltzmann method is applied for performing the two dimensional numerical simulation of the flow structure in a flume with rigid vegetation. A multi-relaxation time model is applied to improve the stability of the numerical scheme for flow with high Reynolds number. The vegetation induced drag force is added in lattice Boltzmann equation model with the algorithm of multi-relaxation time in order to improve the simulation accuracy,. Numerical simulations are performed for a wide range of flow and vegetation conditions and are validated by comparing with the laboratory experiments. Analysis of the simulated and experimentally measured flow field shows that the numerical simulation can satisfactorily reproduce the laboratory experiments, indicating that the proposed lattice Boltzmann model has high accuracy for simulating flow-vegetation interaction in open channel. / National Natural Science Foundation of China (grant number: 11861003 and 11761005)

In river ecology the description and understanding of near-natural ecosystem functionality is a difficult task to achieve as the majority of river floodplains have been intensively impacted by human activities. This work addresses ecological functionality of a relatively unimpacted large river system, focussing on the lateral dynamic and connectivity mechanisms driving aquatic vegetation processes. Macrophytes were found to be very patchily distributed at the riverscape scale, being mainly confined to low energy lateral habitats in the floodplain, such as backwaters. Backwaters provided favourable conditions for plants to colonise and recruit and contributed highly to species diversity and productivity at the floodplain scale. Differences between backwaters were attributed to the frequency of connectivity with the main channel during flood events. Nevertheless, the ecological mechanism driving diversity through flooding appears not to be related to flow disturbance. Biomass produced in backwaters was found to remain stable after potentially scouring floods. Therefore the hypothesis that flood disturbances promote species diversity through the removal and destruction of biomass and rejuvenate communities such that species coexistence is increased was rejected. Rather, it appears that diversity in backwaters increases along a temporal gradient as a response to the input of colonists and their accumulation overtime through successive flood inputs. Despite the apparently non-destructive effect of floods on macrophyte biomass, backwaters appear to have a significant role in exporting large amounts of plant propagules from the site of production. Backwaters represented a net source of propagules which highly enriched the main channel pool of potential colonists. However, whereas propagules could be dispersed for long distances in flood flows the probability for them to reach a suitable downstream habitat was extremely low. This work showed that dispersal at baseflow and entry to backwaters through the downstream end after short dispersal drift provided a greater chance of successful colonisation despite the individually much shorter distance moved. Backwaters were demonstrated to be rather isolated aquatic habitats, even though they experience hydrological connectivity, suggesting that primary colonisation of these sites is a limiting step. Instead, colonisation was shown to rely primarily on propagules generated internally by established plants. Whereas colonisation could occur via internal re-organisation of existing plant propagules, the backwater seed bank could also contribute to the macrophytes species established in backwaters. Such contribution was consistently low to medium along a gradient of disturbances and connectivity and showed independence from such river flow processes. Species richness was found to be higher in the established species than in the seed bank, suggesting that asexual reproduction is prioritised by aquatic vegetation in riverine backwaters. The occurrence or persistence of macrophyte species in backwaters depends upon rhizome and plant shoot regeneration. The lack of influence of connectivity revealed that plants may originate from both in situ and externally waterborne vegetative propagules derived from other upstream backwaters. This research demonstrated that the lateral dynamic and associated connectivity are major components of river floodplain ecology which generate a wide spectrum of habitats and have a controlling effect on vegetation processes. Therefore a naturally dynamic ecological state is required to support ecosystem functionality in large river floodplains and especially to maintain a high level of species diversity, productivity and colonisation of backwaters by macrophytes.

Made available in DSpace on 2014-06-11T19:30:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-05-25Bitstream added on 2014-06-13T19:06:11Z : No. of bitstreams: 1 boschi_ls_dr_prud.pdf: 3170628 bytes, checksum: e8c33fe726b1f0ca366ff51cc7177d42 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As plantas aquáticas têm um papel fundamental no equilíbrio dos ambientes aquáticos e importância crucial no fornecimento de alimento e refúgio para animais. Porém, seu crescimento desequilibrado pode obstruir canais, represas e reservatórios e reduzir a disponibilidade de água para uso humano. No que se refere a plantas aquáticas submersas, a utilização de medidas de controle torna-se mais complexa, face à dificuldade em mapear e quantificar volumetricamente as áreas de infestação. Nessas situações, considera-se que a combinação de dados georreferenciados oriundos de sensores baseados tanto na energia eletromagnética do espectro óptico, como em sinais acústicos, possibilite o mapeamento e mensuração dessas áreas, auxiliando na elaboração de propostas de manejo sustentáveis para esse tipo de vegetação aquática. Assim, o presente trabalho prevê a utilização integrada de dados ópticos e acústicos, para estimar o biovolume de plantas aquáticas submersas. As análises foram conduzidas a partir de dados obtidos em três levantamentos ecobatimétricos e espectrorradiométricos (abril de 2010, novembro de 2010 e janeiro de 2011) realizados em uma área de estudos localizada no Rio Paraná, caracterizada pela dificuldade de navegação, e para a qual foi adquirida a imagem World View-2 em dezembro de 2010. A correlação entre biovolume de plantas aquáticas submersas e valores de brilho registrados em bandas do espectro óptico visível da imagem World View-2 foi menor que 60%, inviabilizando a utilização dos dados espectrais para espacialização do biovolume... / Aquatic plants are fundamental for the balance of opened aquatic environments and crucial in providing food and shelter for animals. However, its unbalanced growing can clog channels, dams and reservoirs, reducing water availability for human use. In the case of submerged aquatic vegetation, the use of control actions becomes more complex due to the difficulty in mapping and volumetrically quantifying the areas of infestation. In these situations, it is considered that georeferenced data – originated both in sensors based on electromagnetic energy of the optical spectrum and acoustic signals – allow the mapping and measuring of these areas, helping to create proposals for the sustainable management of this type of aquatic vegetation. This work uses optical and acoustic data integration method for estimating the biovolume of submerged aquatic vegetation and performing the biovolume mapping. The analysis was performed by using data from three hydroacoustic and spectroradiometer surveys – April 2010, November 2010, and January 2011 – carried out in a test area located in the Paraná River, characterized by the difficulty of navigation. A World View-2 image of this area was acquired in December 2010 to be used in this work. The correlation between the biovolume of submerged aquatic vegetation and brightness values recorded in the visible optical spectrum bands was less than 60%, precluding the use of spectral data for spatial distribution of biovolume through the adjustment of a regression... (Complete abstract click electronic access below)

Orientador: Maria de Lourdes Bueno Trindade Galo / Banca: João Fernando Custódio da Silva / Banca: Nilton Nobuhiro Imai / Banca: Cláudio Clemente Faria Barbosa / Resumo: As plantas aquáticas têm um papel fundamental no equilíbrio dos ambientes aquáticos e importância crucial no fornecimento de alimento e refúgio para animais. Porém, seu crescimento desequilibrado pode obstruir canais, represas e reservatórios e reduzir a disponibilidade de água para uso humano. No que se refere a plantas aquáticas submersas, a utilização de medidas de controle torna-se mais complexa, face à dificuldade em mapear e quantificar volumetricamente as áreas de infestação. Nessas situações, considera-se que a combinação de dados georreferenciados oriundos de sensores baseados tanto na energia eletromagnética do espectro óptico, como em sinais acústicos, possibilite o mapeamento e mensuração dessas áreas, auxiliando na elaboração de propostas de manejo sustentáveis para esse tipo de vegetação aquática. Assim, o presente trabalho prevê a utilização integrada de dados ópticos e acústicos, para estimar o biovolume de plantas aquáticas submersas. As análises foram conduzidas a partir de dados obtidos em três levantamentos ecobatimétricos e espectrorradiométricos (abril de 2010, novembro de 2010 e janeiro de 2011) realizados em uma área de estudos localizada no Rio Paraná, caracterizada pela dificuldade de navegação, e para a qual foi adquirida a imagem World View-2 em dezembro de 2010. A correlação entre biovolume de plantas aquáticas submersas e valores de brilho registrados em bandas do espectro óptico visível da imagem World View-2 foi menor que 60%, inviabilizando a utilização dos dados espectrais para espacialização do biovolume... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Aquatic plants are fundamental for the balance of opened aquatic environments and crucial in providing food and shelter for animals. However, its unbalanced growing can clog channels, dams and reservoirs, reducing water availability for human use. In the case of submerged aquatic vegetation, the use of control actions becomes more complex due to the difficulty in mapping and volumetrically quantifying the areas of infestation. In these situations, it is considered that georeferenced data - originated both in sensors based on electromagnetic energy of the optical spectrum and acoustic signals - allow the mapping and measuring of these areas, helping to create proposals for the sustainable management of this type of aquatic vegetation. This work uses optical and acoustic data integration method for estimating the biovolume of submerged aquatic vegetation and performing the biovolume mapping. The analysis was performed by using data from three hydroacoustic and spectroradiometer surveys - April 2010, November 2010, and January 2011 - carried out in a test area located in the Paraná River, characterized by the difficulty of navigation. A World View-2 image of this area was acquired in December 2010 to be used in this work. The correlation between the biovolume of submerged aquatic vegetation and brightness values recorded in the visible optical spectrum bands was less than 60%, precluding the use of spectral data for spatial distribution of biovolume through the adjustment of a regression... (Complete abstract click electronic access below) / Doutor

Submerged aquatic vegetation (SAV) is an important source of food for waterfowl. Effects of waterfowl grazing on SAV has foremost been studied in freshwater and agricultural ecosystems. This study used drone-based remote sensing to identify waterfowl grazing patterns and quantify the effect their grazing has on SAV in shallow coastal areas in Västerbotten County. Six subareas containing a total of 27 bays were studied in detail. Grazed areas were delimited by polygons in GIS. Using GIS, layers containing water depth, wave exposure and biotope were added to polygons and mean-values were calculated. Field data containing types of SAV were noted in grazed areas and compiled by number of observations. Data was tested in a regression analysis and a X2-test. Results revealed no connection between water depth and wave exposure in regard to the proportion of grazed area. Grazing was identified in 20 out 27 bays and in 41 out of 126 drone images. Field data containing charophytes often overlapped with polygons for grazed areas, but a more systematic collection of data is needed to conclude whether the presence of charophytes is crucial for the choice of grazing area. Shallow coastal areas can have a great variance in SAV species composition from year to year due to ice scraping during winter and yearly land raise. Continuous studies of these areas are therefore needed in order to conclude if changes in SAV species composition is due to abiotic factors or grazing from waterfowl.

Runtom i Sverige och Europa skapar igenvuxna sjöar och vattendrag allt fler problem, vilket bland annat beror på klimatförändringar och mänsklig påverkan. En av de främsta anledningarna till igenväxning av sjöar och vattendrag är övergödning. Studiens syfte är att utvärdera om det är möjligt att på ett automatiskt sätt identifiera utbredning av vattenvegetation i sjöar och vattendrag med hjälp av fjärranalys och GIS. En analys av vegetationsförändringar i sjön Sottern i Uppland genomförs, där utbredd igenväxning skapar problem och där röjningsmaskiner används för att hantera vegetationen, som främst består av bladvass, näckrosor och annan flytande vatten-vegetation. Genom tillämpning av olika klassificeringsalgoritmer, bandkombinationer och vegetationsindex undersöks förändringar i sjöns tillstånd genom att klassa Sottern i två huvudklasser, vatten och vattenvegetation. Studien baseras på fjärranalysdata från den optiska satellitkonstellationen Sentinel-2 och en högupplöst referensbild från Google Earth Pro. Data samlades in under växtsäsongen, maj till oktober, för åren 2021 och 2022 för att analysera om och hur vattenvegetationen förändras över tid. Resultaten visar att Maximum Likelihood Classification (MLC) framträder som den mest effektiva algoritmen för att studera vegetationsförändringar, särskilt om den appliceras på en "False color" bandkombination bestående av banden 8 (NIR), 4 (rött) och 3 (grönt). MLC visar högre (94%) noggrannhet jämfört med Random Trees (RT) och Support Vector Machine (SVM). Genom att tillämpa vegetationsindexet NDVI (Normalized Difference Vegetation Index) ger studien en fördjupad förståelse för hur vegetationen förändras över tid. Genom att kombinera resultaten från dessa metoder går det att dra slutsatser om hur vattenvegetationen breder ut sig över tid i sjön Sottern, där en tydlig ökning av vattenvegetation sker mellan mitten av maj till mitten av juni, medan minskningen av vattenvegetationen inte är lika konsekvent. / In Europe, overgrown lakes and watercourses are creating increasing problems, which are partly due to climate change and human impact. One of the main reasons for the overgrowth of lakes and watercourses is eutrophication. The aim of the study is to evaluate the possibility of automatically identifying overgrown lakes and watercourses using remote sensing and GIS. An analysis of vegetation changes in Lake Sottern in Uppland county, Sweden is conducted, where overgrowth creates problems and where clearing machines are used to manage the vegetation, primarily consisting of reeds, water lilies, and other aquatic vegetation. By applying various classification algorithms, band combinations and vegetation indices, changes in the lake's condition are investigated by classifying Sottern into two main classes: water and aquatic vegetation. The study is based on remote sensing data from the optical satellite constellation Sentinel-2 and a high-resolution reference image from Google Earth Pro. Data were collected during the growing season, from May to October, for the years 2021 and 2022 to analyze if and how aquatic vegetation changes over time. The results show that Maximum Likelihood Classification (MLC) emerges as the most effective algorithm for identifying aquatic vegetation, especially when combined with a "False color" band combination consisting of bands 8 (NIR), 4 (red), and 3 (green). MLC shows higher accuracy compared to Random Trees (RT) and Support Vector Machine (SVM). By applying the Normalized Difference Vegetation Index (NDVI), the study provides a deeper understanding of how vegetation changes over time. By combining the results from these methods, it is possible to draw conclusions about how aquatic vegetation changes over time in lakes like Sottern, where a clear increase in aquatic vegetation occurs between May and June, while the decrease in aquatic vegetation is not as consistent.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-08-19T14:06:23Z No. of bitstreams: 1 PDF - Rayssa Soares da Silva.pdf: 6993577 bytes, checksum: 4b28a1b3bf1dccef7a141f2729ec2180 (MD5) / Made available in DSpace on 2016-08-19T14:06:23Z (GMT). No. of bitstreams: 1 PDF - Rayssa Soares da Silva.pdf: 6993577 bytes, checksum: 4b28a1b3bf1dccef7a141f2729ec2180 (MD5) Previous issue date: 2016-02-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Seagrass beds are essential habitats for the high biodiversity in coastal environments. They provide nursery, feeding and shelter areas for many organisms. Despite its importance, the seagrass beds are among the most threatened coastal ecosystems on the planet and its influence on fish populations has been little studied in Brazil. The understanding of its influence on the dynamics of fish assemblages associated with these environments and the study of the feeding habits of the species that use them supports the development of new conservation policies of these habitats. Thus, the aim of this study was to compare the composition, structure and feeding ecology of fish assemblages found in vegetated and unvegetated areas on the estuary of the Mamanguape River, Paraiba - Brazil, observing the variations in hydrological conditions between the dry and rainy periods. The values of abundance and biomass were higher in non-vegetated areas, although there was no significant difference in species diversity between study areas. Thus, the environmental stability of unvegetated areas proved to be an important factor in determining the biomass and richness patterns. In addition, it was observed that these areas are used by the species at different stages of their ontogenetic development according to the ratio of optimal foraging and the possibility of refuge from predation. Among the species captured in vegetated and unvegetated áreas on the estuary, the four most representative were selected for analysis of stomach contentes, according to their abundance. Of these, three were considered generalists and showed a high degree of individual specialization, supporting the hypothesis of niche variation proposed by Van Valen. Also, we observed the importance of intraspecific competition and the availability of food items in the intraindividual variation in the diet of the species. / Os bancos de fanerógamas marinhas são habitats essenciais para a elevada biodiversidade em ambientes costeiros, pois constituem áreas de berçário, alimentação e refúgio para diversos organismos. Apesar de sua importância, os bancos de fanerógamas estão entre os ecossistemas costeiros mais ameaçados do planeta e sua influência sobre a ictiofauna foi pouco estudada no Brasil. O entendimento da sua influência sobre a dinâmica das assembleias de peixes associados a estes ambientes e o estudo dos hábitos alimentares das espécies que os utilizam auxilia no desenvolvimento de novas políticas de conservação destes habitats. Deste modo, o objetivo deste estudo foi comparar a composição, estrutura e ecologia alimentar de assembleias de peixes encontradas em áreas vegetadas e não vegetadas do estuário do Rio Mamanguape, Paraíba – Brasil, observando as variações do regime hidrológico entre os períodos seco e chuvoso. Os valores de abundância e de biomassa foram maiores nas áreas não vegetadas, apesar de não haver diferença significativa da diversidade de espécies entre áreas estudadas. Deste modo, a estabilidade ambiental das áreas não vegetadas mostrou -se como fator importante na determinação dos padrões de biomassa e riqueza de espécies. Além disso, foi observado que essas áreas são utilizadas pelas espécies em diferentes fases do seu desenvolvimento ontogenético de acordo com a razão entre o forrageamento ótimo e a possibilidade de refúgio contra a predação. Dentre as espécies capturadas nas áreas vegetadas e não vegetadas do estuário do rio Mamanguape as mais representativas foram selecionadas, de acordo com sua abundância, para análise do conteúdo estomacal. Das quatro espécies, três delas foram consideradas generalistas e apresentaram um alto grau de especialização individual, corroborando com a hipótese da variação de nicho proposta por Van Valen. Além disso, observou-se a importância da competição intraespecífica e da disponibilidade de itens alimentares na variação intraindividual da dieta das espécies.