A Ilha Comprida, localizada no litoral sul do Estado de São Paulo, é uma ilha-barreira arenosa holocênica de 63 km de comprimento por até 5 km de largura, limitada a SW pela desembocadura de Cananéia, e a NE, pela desembocadura de Icapara. Seu sistema praia - duna frontal teve grande variação no tempo, como evidenciado por sucessivos truncamentos de cordões litorâneos. Em escala de tempo mais restrita, dentro dos últimos 200 anos, coberta pelo registro histórico e cartográfico e por fotografias aéreas, as mudanças morfológicas mais significativas concentram-se no extremo nordeste da ilha. Incluem a variação de largura na área hoje caracterizada pelo máximo estrangulamento da ilha, a formação de um pequeno campo de dunas transgressivo nesta mesma área, o surgimento em 1943 de uma projeção da linha de costa, atualmente em estágio avançado de erosão, e o aparecimento intermitente e sucessivo de embaiamentos lagunares no setor adjacente da ilha de Iguape. A abertura do canal artificial do Valo Grande, em 1852, atuou de modo direto ou indireto em pelo menos parte destas mudanças. O aumento de vazão, de retrabalhamento de sedimentos arenosos e portanto de aporte de carga de fundo, devido ao Valo Grande, induziu o surgimento de ilhas arenosas e a formação de ?manchas de areia? no fundo do canal lagunar, bem como a intensificação da dinâmica de meandramento da desembocadura de Icapara, implicando possível aceleração na migração desta desembocadura rumo NE e no próprio crescimento longitudinal da barreira. O sistema praia - duna frontal da Ilha Comprida apresenta também grande variação no espaço, evidenciada pela alternância ao longo de sua extensão de morfologias diferentes, o que pode ser atribuído à intercalação entre setores de caráter deposicional e erosivo. As extremidades da barreira caracterizam-se pela ocorrência marcante de pequenos campos de nebkhas sobre terraços baixos de dunas frontais (<0,5 m). A presença dessas feições pode ser relacionada à contínua progradação próximo às desembocaduras lagunares de Icapara e de Cananéia. A zona erosiva mais evidente encontra-se na extensão centro-sul da praia, como evidenciado pela ocorrência de cordões antigos truncados pela linha de costa atual, e pela redução em tamanho de dunas frontais ativas incipientes e estabelecidas, as quais aparecem por vezes com falésias vivas associadas. Na mesma região, a morfodinâmica muda de regime dissipativo para intermediário, com presença de cúspides de espraiamento e berma. Esta região, ademais, concentra a mais alta variabilidade e complexidade de morfologia de dunas (i.e. cordões de dunas incipientes e estabelecidas obliquamente amalgamadas), além de uma concentração maior de dunas do tipo rampa. No restante do sistema, predomina ampla face de praia de baixa declividade (média de 0,66o), com tendência para formas mais estáveis de dunas frontais (terraços e cordões). Medidas estatísticas de distribuição granulométrica (diâmetro médio, desvio-padrão e assimetria) obtidas através do método dos momentos de Pearson, permitiram inferir, pela regra de McLaren, duas células de deriva litorânea longitudinal principais. A célula nordeste, dirigida para NE, abrange aproximadamente 53 km, e a célula sudoeste toma em sentido oposto (SW) os restantes 10 km. As duas zonas de pólo deposicional de deriva são caracterizadas por amplos e baixos terraços de dunas frontais incipientes progradacionais. A zona de divergência entre as células de deriva coincide com a região de erosão costeira mais intensa. A distribuição em massa de minerais pesados é concordante com o transporte longitudinal verificado. Responde a isso a tendência de aumento de minerais de menor equivalente hidráulico (em geral, quimicamente mais instáveis) a despeito da redução de minerais de equivalente hidráulico mais alto (em geral, quimicamente mais estáveis) no rumo de transporte. A integração dos resultados obtidos por análise morfológica (fotointerpretação e estudo de feições de campo) e sedimentológica (granulometria e minerais pesados) permitiu estabelecer um modelo morfodinâmico para o sistema praia - duna frontal recente da Ilha Comprida. Neste modelo, a fase final de evolução da ilha é atribuída tanto à superação do obstáculo ao crescimento longitudinal exercido pelo morro de Icapara, quanto ao incremento de carga sedimentar na desembocadura de Icapara, induzido pela abertura do Valo Grande. / Ilha Comprida is a Holocene sandy barrier-island located on the south coast of São Paulo State, 63 km long and 2 to 5 km wide. Its transverse boundaries are Cananéia and Icapara inlets, at the SW and NE, respectively. The beach-foredune system of Ilha Comprida have experienced intense morphological variation in time, as showed by the successive truncations of littoral ridges. In a more restricted time-scale (at least 200 years) as covered by historical and cartographic records and aerial photographs, the most relevant changes have occurred on the northeast extremity of the island. These changes include: i) variation in width at the present most narrow region; ii) formation of a little transgressive dunefield (2 km2) in the same region; iii) initiation (in 1943) of a projection in the coastline, actually in advanced erosional state; iv) intermittent and successive appearing of lagoonal embayments at the neighboring sector of the Iguape island. The opening of the Valo Grande artificial channel, in 1852, acted either directly and indirectly on these changes. The increase of sedimentary bed-load supply induced the appearance of sand islands and submerged sand patches along the lagoonal channel. Beside this, the increasing meandering of Icapara inlet forced its rapid migration to the NE, and the longitudinal growing of the barrier. The beach-foredune system also shows great variability alongshore, observed on the morphologic alternance of depositional and erosional sectors. The tips of the barrier are characterized by the marked occurrence of small nebkha fields on foredune terraces (up to 0.5 m high). These aeolian morphological features can be related with a continuous progradation nearly Icapara and Cananéia inlets. The most-evidenced erosional zone stays at the mid-southwestern portion of the beach, as observed on the truncation of former beach and foredune ridges by the present coastline, and on the reduction in size of active incipient and established foredunes (that often appears with active cliffs). In the same region, the coastal morphodynamics changes from dissipative to intermediary beach, with presence of swash cusps and berm. Moreover, this site concentrates the highest variability and complexity of dune morphology (e.g. obliquely amalgamated incipient and established foredune ridges), beyond a increasing occurrence of ramp foredunes. In the remains of the beach-dune system, large shorefaces of low declivity (0.66o in mean), with tendency to more stable shapes of foredunes (terraces and ridges), are dominant. Statistical measures on the distribuition of granulometric frequencies (mean diameter, standard deviation, skewness), calculated through the Pearson?s moments method, indicate according to the McLaren rule two main longshore drift cells. The northeastern cell, oriented towards the NE, comprises about 53 km. The southwestern cell, comprising the remaining 10 km, is oriented towards the SW. The two depositional poles of longshore drift cells are characterized by wide and flat progradational, incipient foredune terraces. The divergence zone among these longshore cells drift coincides with the zone of the most intense coastal erosion. The mass distribution of heavy minerals is in agree with the deduced directions of longshore transport. This fact is confirmed by the tendency of increasing concentration of minerals with minor hydraulic equivalence (usually, more unstable minerals) in despite of reduction of minerals with high hydraulic equivalence (usually, more stable minerals) along the net longshore drift direction. The integration of data obtained by morphologic analysis (interpretation of aerial photographs and field features) and sedimentology (grain size, heavy minerals), allowed to postulate a morphodynamic model for the recent beach-foredune system of Ilha Comprida. According to this model, the late phase of barrier evolution is related both to the surpassing an obstacle to longitudinal growth (Icapara hill), and to the increasing sedimentary input at the Icapara inlet, favored by the opening of the Valo Grande channel.

The Byron Bay Sewage Treatment work consists of a conventional treatment system discharging into an 8 ha wetland. The wetland was constructed around the dune and swale remnants of a coastal beach ridge formation. The wetland design incorporated stands of broad leaf paperback, Melaleuca quinquenervia , in two distinct Sections, separated by, and each preceded by, open water Sections fringed by predominantly emergent macrophytes. Spatial and temporal patterns in sediment phosphorus concentrations were examined using sediment cores. Core consisted of three main sediment types - surface organic accumulation, pre-existing organic layers and sand. Results suggest that the design and management of wetland systems should be aimed at maximising the deposition of sediment (and associated phosphorus) and minimising subsequent phosphorus release from the sediment. This might be achieved through the removal of accumulated organic sediments to retain the phosphorus adsorption capacity of the system, consideration of wind direction during periods of high (floating) plant growth (as detritus may accumulate along the up-wind edges of the wetland), incorporation of deep zones to minimise sediment phosphorus release and the inclusion of stands of M. quinquenervia. Results highlight pitfalls in the prevailing approach to wetland design, which ignore the complex functions which occur in natural wetland systems. A more holistic approach incorporating a high diversity of ecozones in wetland design is proposed, in effect mimicking natural systems. / Master of Science (Hons)

<p>The aim of this thesis is to describe present and past coastal dune environments in southern Buenos Aires Province, Argentina. </p><p>The present vegetation of a dune system and its zonation are described on the basis of air photographs, physiognomy of the dune system and floristic composition. The vegetation was characterized by a large number of Poaceae and Asteraceae species. Five vegetation zones, based on floristic composition, were defined by cluster analysis. </p><p>Pollen-vegetation comparison revealed that pollen assemblages differed considerably from the associated vegetation. Some of the major discrepancies were caused by large differences between pollen and vegetation proportion of <i>Hyalis argentea</i> and <i>Discaria americana</i>. However, the local vegetation was well represented in recent soil samples. Pollen traps recorded predominantly extralocal and regional pollen. </p><p>A new species of ostracods was recovered from an interdunal lake. The species, a giant cypridid, was described and illustrated, and its geographical distribution and ecology were discussed. </p><p>Two sediment sequences from the coastal intertidal zone and from a shallow freshwater lake were analysed for loss on ignition, calcareous microfossils (ostracods and foraminifers), macro remains and pollen. The coastal sequence was deposited between 7890 and 7630 cal. BP. Its pollen assemblages were typical for halophytic associations, with some psammophytic taxa also present in recent vegetation. The microfossils were representative of a littoral lagoon. The lake sequence comprised the last 3000 cal. BP. Pollen spectra indicated a relatively stable vegetation composition after the lake had been formed. Pollen assemblages reflected the present regional grassland vegetation with taxa characteristic for the surrounding dune communities. Human settlement was indicated in the pollen spectra by the presence of introduced taxa in the uppermost samples. </p><p>The data presented provide a useful reference for the interpretation of fossil sequences from similar environments.</p>

The aim of this thesis is to describe present and past coastal dune environments in southern Buenos Aires Province, Argentina. The present vegetation of a dune system and its zonation are described on the basis of air photographs, physiognomy of the dune system and floristic composition. The vegetation was characterized by a large number of Poaceae and Asteraceae species. Five vegetation zones, based on floristic composition, were defined by cluster analysis. Pollen-vegetation comparison revealed that pollen assemblages differed considerably from the associated vegetation. Some of the major discrepancies were caused by large differences between pollen and vegetation proportion of Hyalis argentea and Discaria americana. However, the local vegetation was well represented in recent soil samples. Pollen traps recorded predominantly extralocal and regional pollen. A new species of ostracods was recovered from an interdunal lake. The species, a giant cypridid, was described and illustrated, and its geographical distribution and ecology were discussed. Two sediment sequences from the coastal intertidal zone and from a shallow freshwater lake were analysed for loss on ignition, calcareous microfossils (ostracods and foraminifers), macro remains and pollen. The coastal sequence was deposited between 7890 and 7630 cal. BP. Its pollen assemblages were typical for halophytic associations, with some psammophytic taxa also present in recent vegetation. The microfossils were representative of a littoral lagoon. The lake sequence comprised the last 3000 cal. BP. Pollen spectra indicated a relatively stable vegetation composition after the lake had been formed. Pollen assemblages reflected the present regional grassland vegetation with taxa characteristic for the surrounding dune communities. Human settlement was indicated in the pollen spectra by the presence of introduced taxa in the uppermost samples. The data presented provide a useful reference for the interpretation of fossil sequences from similar environments.

Foredunes are formed and developed in association with vegetation. A bare sand area has been viewed as a measure of dune mobility or activity and researched in association with climate controls: particularly wind power, annual mean precipitation, and temperature, expressed in annual mean potential evapotranspiration. There has been no research that utilized the patterns of bare sand areas to classify foredune areas in coastal dune systems and investigated climate controls related to sand patch patterns, or “foredune textures” such as size, number, and distribution of sand patches Four foredune types were classified based on four landscape metrics (PLAND: percentage of bare sand area, PLADJ: proportion of like-adjacencies, NLSI: normalized landscape shape index, and ENN_RA: range of Euclidean nearest neighbor), by applying the concepts and methodologies of landscape ecology. Four climate variables (annual mean precipitation, annual mean potential evapotranspiration, Lancaster’s mobility index, and the standard deviation of annual mean precipitation) were found to affect the foredune types and help in distinguishing one foredune type from another. The amount of bare sand area on coastal foredune areas can be explained by annual mean precipitation (R^2 is 0.52 at the 99 % confidence level), standard deviation of precipitation (R^2 is 0.51 at the 99 % confidence level), and Lancaster’s mobility index (R^2 is 0.37 at the 99 % confidence level) but wind variables such as drift potential do not explain much (R^2 is 0.04 at maximum). This suggests that dune activity or stabilization in coastal dune systems is mainly controlled by vegetation cover, which is in turn affected by precipitation. Foredune textures can be a useful tool to predict foredune types in association with future climate change, and the optimal averaging period of precipitation for each bare sand area was seven years.

Coastal ecosystems provide important resources for social, economic and environmental capital to global and local communities. Socially, coastal ecosystems provide a place for people to recreate and get in touch with nature. Economically, tourism, fisheries, and businesses are dependent upon coastal resources. Environmentally, coasts provide habitat for diverse species of flora and fauna, and protection for watersheds and anthropogenic structures. This research investigates three studies in order to provide information on social, economic and environmental issues in Matagorda, Texas. The first study uses LIDAR (Light Image Detection-and-Ranging) scanning, a remote sensing methodology that uses laser pulses to collect X, Y, and Z coordinates, to evaluate coastal changes after Hurricane Ike. Results suggest that landscape loss occurs immediately after the hurricane, but recovers and fluctuates throughout the year. Also, different areas of the dunes show unique changes during different times of the year. The second study uses questionnaire surveys to collect demographic, social perspectives and opinions and economic information about coastal users on Matagorda Peninsula. The questionnaire investigates the most important characteristics to beach users, opinions and perceptions about beach safety, activities, maintenance and presence of seaweed, information about their trip, cost of their trip and demographics. The results provide broader knowledge about the beach users in Matagorda and indicate that while direct costs of using the beach are minimal, the indirect and intrinsic costs are much higher which result in a greater overall use value. The third study investigates the use of the sargassum, a natural marine subsidy, as a fertilizer for dune plants. Beach raking provides a cleaner, more aesthetically pleasing experience for beach users but alters the natural design of the ecosystem by subsequently moving sand, nutrients, subsidies for habitat and fauna from the fore-beach to the dunes. Results show that sargassum does have potential as a natural fertilizer as it did not negatively affect any of the species. The results could be used to alter management practices in order to capitalize on this natural resource while still providing a clean sandy beach for recreationalists. These three studies together provide ecological information about coastal functions and processes that can help in creating broad holistic science based management strategies.

The alongshore variability of beach-dune systems and the response and recovery from extreme storms remains poorly understood. The height and extent of foredunes along barrier islands varies over a range of spatial scales, implying that during extreme storms, the beach-dune system should respond in different ways depending on the elevation and volume of the dunes relative to the storm surge. The purpose of this study is to use Ground-Penetrating Radar (GPR) and vibra-cores to investigate the internal structure of small, intermediate and large dunes along a 2.5 km transect of beach in Padre Island National Seashore, TX with particular attention to storm impacts. A series of dune normal and parallel GPR profiles were collected to capture the variation in beach-dune morphology at the three sites. Site locations were chosen along a transition from dissipative to intermediate beach states. Following the Sallenger (2000) storm impact model, the small dune is defined by low-lying topography that is susceptible to overwash and inundation depending on the size of the storm surge. The large dune is characteristic of the “collision regime”, while the intermediate dune represents a transition between “overwash” and “collision regimes”, with the underlying assumption that all three dunes would be impacted by the same level of surge during a single storm event. Results from the GPR survey suggest that each site contains a bright, laterally continuous radar reflector that is interpreted with the aid of the sedimentary data as an erosional layer. Different characteristic radar facies and sequence boundaries provide evidence as to how each dune evolved through and after the storm. Results from XRF scans and grain size analysis show a direct comparison between the GPR reflectors at the storm surface and spikes in calcium counts from XRF scans to distinct changes in grain size parameters at the same depth. It is argued that the location of each shell layer corresponds to a storm surface generated during a single storm, which means it is possible to interpret different recovery mechanisms. The presence of the storm layer across the backbeach and dunes provides evidence for the height and extent of the surge during the storm event. The data suggests that the small dune was overtopped by the surge, experiencing minimal erosion and recovery. The intermediate dune was completely eroded by the surge, but showed the greatest recovery of all the dune sites. The large dune was scoured at the base with marginal impact along its crest and shows minimal recovery after the storm. These results suggest that the evolution (i.e., transgression) of a barrier island varies considerably over short distances.

The impact of development on coastal ecological processes within the coastal zone is often noted as being of ecological concern, due to the suggested destabilization of dune systems as a result of construction activities and post construction impacts such as stormwater disposal, trampling and other artificial influences on, in particular, the plant ecology of the frontal dune systems. Given that the stability of frontal dune systems along the Kwa Zulu Natal north coast is often attributed to the maintenance of vegetation and seral progression on such systems, the identification of changes in dune plant communities that may arise from the influence of proximal or adjacent activities was sought to be identified. Utilising data collected from a number of sites in the Kwa Dukuza Municipal area, the classification and ordination of environmental and botanical species information collated over approximately 6 months was undertaken. The results of this investigation indicate that: Species composition differs in terms of richness and abundance in the three frontal dune vegetation zones sampled. 2 3 4 5 Some species occur in all three zones and others are confined to one zone only. Bearing and the associated influence of wind, the slope and length of the beach, and the steepness ofthe dune face all influence the species composition at any particular site The influence of anthropogenic activities on dune synusia is such that human influence on one species may disrupt associations between species and may result in attenuation or '" reversal of seral movement. Anthropogenic impacts influences species composition at different sites by causing some species to decline abundance or disappear from a site and others to invade or oust established species. In Zone I the species that appears to be most affected by human activity is Gazania rigens, which appears to dominate in sites of high human activity, at the expense of Sporobolus virginicus. In Zone IT under high human activity species such as Cynanchum obtusifolium, Rhoicissus digitata and Sporobolus virginicus dominate, while the woody species Mimusops caffra and Eugenia capensis, as well as the liane Gloriosa superba appear to decline or be ousted from this Zone. In Zone Ill, Asystasia gangetica, is a dominant species where low to moderate human impacts are encountered, while where human impacts are high, species common to Zone I, such as G rigens may become prevalent, ousting A gangetica and grasses such as S virginicus may be ousted by more competitive species such as Stenotaphrum secundatum. It is thus concluded that human activities in and around the frontal dune system may be influential in re-inforcing aeolian impacts on sites with bearings affected by strong prevailing winds. / Thesis (M.Sc.)-University of KwaZulu- Natal,Durban, 2004.

This thesis explores the geomorphic implications of large woody debris (LWD) residing in the backshore of beach-dune systems along the northeastern coasts of Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada. Detailed topographic surveys were employed to quantify seasonal mass balance of the beach-dune systems along two distinctly different coastlines. Erosion and accretion potential models were applied to characterize sediment transport conditions. Holman’s (1986) R2% wave runup model was superimposed on total water levels, to model wave runup exceedence of the beach-dune junction elevation (6.5 m aCD). Modelled ‘erosion potential’ hours were demonstrated to correspond with observed erosion including removal of the LWD zone, resulting in decreased mass balance. Similarly, Fryberger and Dean’s (1979) Drift Potential model was used to model accretion potential hours. Modelled accretion potential hours were also able to effectively describe conditions when actual accretion occurred. The presence of LWD in the backshore offered two functions to the above processes: it acted effectively as an ‘accretion anchor’, promoting increased mass balance and rebuilding of the incipient foredune; and, it offered a mass of sediment fronting the foredune to protect the beach-dune system from storm wave attack and subsequent erosion.

A passagem de um padrão monsoonal para um padrão de circulação atmosférica zonal ocorreu durante o Cretáceo devido à fragmentação do Supercontinente Gonduana. Essa mudança na direção dos paleoventos é registrada no mergulho de estratos cruzados de dunas eólicas acumuladas em várias bacias de Gonduana. Três mapas de reconstrução de paleoventos foram construídos com a integração de dados paleocorrentes compilados de bacias Fanerozoicas brasileiras, Bacia de Neuquén na Argentina e bacias do Congo e Huab na África. O Gonduana foi dominado por ventos do nordeste ao norte e ventos do sudoeste ao sul, deslocando, assim, a Zona de Convergência Intertropical para 15º a 20 sul do equador durante o Jurássico Tardio até o início do Cretáceo. Por sua vez, os ventos apresentaram uma tendência geral para o oeste-noroeste em latitudes baixas e médias no Gonduana no final do Cretáceo Inical. Esses resultados apontam para a existência de um padrão monsoonal durante o Jurássico Tardio até o início do Cretáceo Inicial e a entrada do padrão zonal no final do Cretáceo Inicial, associado à fragmentação de Gonduana. / The passage of a monsoonal pattern to a zonal atmospheric circulation pattern occurred during the Cretaceous due to fragmentation of Gondwana Supercontinent. This change in the paleowind direction is recorded in crossstrata dip directions of eolian dunes accumulated in various basins of Gondwana. Three maps of paleowind reconstruction were built with integration of compiled paleocurrent data from Phanerozoic basins in Brazil, Neuquén Basin in Argentina and Congo Basin and Huab Basin in Africa. Gondwana was dominated by northeast winds to the north and southwest winds to the south, thus shifting the Intertropical Convergence Zone to 15º to 20⁰ south of the equator during Late Jurassic to the beginning of the Cretaceous. In turn, winds had a general tendency towards west-northwest at low and mid-latitudes in Gondwana at the end of Early Cretaceous. These results point to the existence of a monsoonal pattern during the Late Jurassic to the beginning of Early Cretaceous and the entry of zonal pattern at the end of Early Cretaceous, associated with fragmentation of Gondwana.