The St. Lucia Estuary, the largest estuary in South Africa, has been subject to many natural (a decade long drought) and anthropogenic impacts. A particular mouth manipulation activity, the artificial separation of the Mfolozi River and the St Lucia Estuary in 1952, was done to stop the perceived “silting up” of the estuary, but resulted in a decrease in freshwater supply. The changes in inflows (both fresh and marine) are controlled by management decisions and affect other system parameters such as salinity, water level and turbidity, which influence the distribution of biota. Therefore knowledge on the physico-chemical environment and eco-physiological tolerances of macrophytes will lead to informed future management decisions. The first of the three objectives carried out for this study determined the present state and distribution of the macrophytes of the St. Lucia and Mfolozi estuaries. The macrophyte habitats mapped in 2008 and 2013 were the submerged macrophytes, reeds and sedges, mangroves, grass and shrubs, salt marsh (succulent) and swamp forest. Results indicated that low salinity in the lakes and high water level in 2013 caused die-back or expansion of particular habitats. Submerged macrophytes, in particular Stuckenia pectinata, grows well in water with salinity <15 ppt, therefore this habitat increased by 412 ha (96%) in cover since 2008. Salt marsh decreased by 553 ha (57%) due to inundation. Since 2008 the reeds and sedges increased by 390 ha (in North Lake and the Narrows) due to the salinity decrease. In the Narrows the mangroves decreased by 28 ha (9%) in area cover. This was due to the drought that persisted for so many years, which caused low water levels and non-tidal conditions. The second objective was to determine the present state / health of the mangroves at four sites along the Narrows by assessing sediment condition and population structure of the trees. These results were compared to those obtained in 2010. The total density of Avicennia marina increased since 2010, however this was due to the large increase in seedlings at Site 1, the back channel site. The highest sediment salinity (26 ppt) and porewater salinity (29 ppt) was recorded for this site and these results show that this back channel site was strongly influenced by the open Mfolozi Estuary (increase in marine waters) and tidal conditions at the time of sampling in 2013. The total density of Bruguiera gymnorrhiza decreased, but an increase in adults was recorded at Site 2, the freshwater site. The soil collected from the Bruguiera quadrats was fresher and drier than that of the Avicennia quadrats of Site 2. Lack of seedlings (of both species) was due to the dense stands of Acrostichum aureum (mangrove fern) and Phragmites australis (common reed) and a thick, impenetrable mat of Avicennia pneumatophores. At Sites 3 and 4, the drier sites (where sediment moisture contents were the lowest for all sites at 43 and 42% respectively), seedling and sapling density was low, but adults increased in density since 2010. Recruitment and survival were impacted by the harsh environmental conditions that prevailed prior to 2013 (low water level and non-tidal influence), but adults survived. The results of the test that determined the percentage of aerenchyma of the pneumatophores indicated that waterlogging stress did not affect the aerenchyma of the pneumatophores. However the period of inundation was probably not significant enough to have affected the production of aerenchyma. The third objective formed part of an ongoing study by the Global Environmental Facility (GEF) on the feasibility of linking the Mfolozi River back to the St Lucia Estuary and the responses of these systems to different management scenarios: 1) the “do nothing” scenario; 2) maintain separate Mfolozi and St Lucia mouths representing an open mouth condition; and 3) actively facilitate a single mouth (therefore linking the Mfolozi and St Lucia mouths). Data gathered on the eco-physiological tolerances of the dominant macrophyte species was used to predict the response of the different habitats to these various management scenarios and the results indicated that the best management scenario would be to actively facilitate a single mouth (Scenario 3) as the estuary habitats would increase significantly because of preferred tidal and saline conditions, as this would represent more natural conditions. The results of the study will provide input to recommendations for future “adaptive management” strategies for the Global Environmental Facility (GEF) Project.

Estuaries require sufficient quantity, quality and appropriate timing of freshwater inflow, referred to as environmental flow requirements, to ensure adequate health and functioning. In South Africa the environmental flow requirements of estuaries is determined using Resource Directed Measures (RDM). The present health and importance of an estuary must be considered when determining the ecological flow required to maintain an estuary in its desired state. An Estuarine Health Index that quantifies changes in abiotic and biotic components from natural conditions to present day is used. Health of biotic components is assessed according to changes in species richness, abundance and community composition. There has, however, been debate regarding the calculation of these attributes. In particular, for macrophytes, the inclusion of all habitat within the Estuarine Functional Zone (i.e. 5 m topographical contour) would affect the health and changes over time determined in past assessments. This is due to different areas being included as different areas would be included The aim of this study was to test the validity and suggest improvements to South Africa’s RDM macrophyte health score determination. The health of macrophytes were assessed at varying levels of intensity from desktop studies to thorough field studies. Rapid field studies provided a visual estimate of macrophyte health; while the intermediate and comprehensive assessments quantified change by mapping the distribution of macrophyte habitats from aerial photographs. These approaches were applied to the 64 estuaries within the Mvoti-Mzimkulu Water Management Area (WMA 11), situated in KwaZulu-Natal (KZN) on the subtropical east coast. Historically, these estuaries have supported restricted macrophyte habitats. Consequently, estuaries that presently or historically supported range limited habitats such as mangroves and swamp forest are considered important. Submerged macrophytes are scarce in KZN estuaries due to siltation and low turbidity and thus estuaries supporting this macrophyte habitat are also important. Based on available literature important estuaries were highlighted and selected for field studies. Transects spanning from the estuary water channel to the boundary of the EFZ provided a generalised distribution of KZN vegetation along an elevation gradient. The transition from estuarine to terrestrial vegetation can be used to improve the current EFZ boundaries, as estuarine area has been found to occur outside of the 5 m contour in some estuaries. Results from the desktop assessment indicated that most of the estuaries are moderately modified. There was a 50 % similarity in the macrophyte health scores determined by the desktop assessment to the 2011 National Biodiversity Assessment (NBA). Field studies mostly confirmed the desktop assessment aside from seven estuaries that had different scores. There has been a significant loss of macrophyte habitat with 100% loss of certain habitats from 9 of the 22 estuaries for which there were field assessments. Submerged macrophytes were not found at any of the estuaries that were assessed in the field. Black mangroves, Bruguiera gymnorrhiza (L.) Lam., were rediscovered at Ngane Estuary, however the few individuals could not be considered a ‘mappable’ community (i.e. <0.5 ha). Mtamvuna and Mkomazi estuaries both supported small stands of mangroves that, compared to data from 2006, appeared healthy. Macrophyte habitats and surrounding coastal forest matched the species composition described in the Vegetation Map of South Africa. The freshwater mangrove or Powder puff tree, Barringtonia racemosa (L.) Roxb, was not abundant in the estuaries. It was only found at four (Damba, Fafa, Little Amanzimtoti and Mvoti) of the estuaries that were assessed in the field. Important estuaries, from a botanical perspective, included some of the larger estuaries such as Mgeni, Durban Bay and Sipingo. Smaller, healthier estuaries that presently support mangrove and swamp forest habitat were also identified as important from a botanical perspective. Macrophyte habitats have mainly been lost due to non-flow related pressures. Sugarcane cultivation occurred within the floodplain of 25% of the estuaries. Nutrient enrichment was evident for 12.5% of the estuaries and reed encroachment was evident for 27% of estuaries for which there were field assessments. Development, aside from the N2 road bridges, was evident for 40% of the estuaries assessed in the field. Invasive plant species, including aquatic invasive plants, were present in all estuaries assessed in the field. The extent of invasive plant species was related to the degree of disturbance and surrounding land use pressures. The Mkomazi and Mvoti estuaries that were assessed at a comprehensive level, as they have earmarked for further water abstraction, had the poorest macrophyte health scores. The macrophyte health of these estuaries was much lower than previously determined by the NBA. The decline in health was attributed to the removal of macrophyte habitat for sugarcane cultivation and development as well as displacement by invasive plant species. The areas covered by the macrophyte habitats also differed from the NBA highlighting the importance of updated mapping and ground truthing. Largely differing macrophyte health scores were produced when attributes were calculated using different combinations of macrophyte habitats. Results indicate that only macrophyte habitats and no other floodplain vegetation should be included when calculating abundance. All macrophyte habitats, physical habitats and floodplain should be incorporated when calculating community composition. The minimum of these attributes is used as the overall macrophyte health score as a precautionary approach is followed. Scoring of health is subjective and the only benchmark for determining the most appropriate method is comparion with previous RDM studies. This study illustrates the need for a standardised RDM scoring method that is presented in a manner that ensures the same results irregardless of the speciliast conducting the study. The updated estuary health and importance scores for WMA 11 are necessary to inform management, particularly as few of the estuaries receive formal protection. In conclusion, this study contributed to the limited knowledge of the estuaries of WMA 11 and assisted in determining appropriate methods for assessing the health and importance of estuary macrophytes.

“An estuary is a partially or fully enclosed body of watera) which is open to the sea permanently or periodically; b) within which the sea water can be diluted, to an extent that is measurable, with freshwater drained from inland” (National Water Act, 1998). Estuaries are ecologically important because they are habitats for birds, fish and plants and they are valuable because they provide human beings with food (fish) and recreational pleasure in the form of unique views, bird watching and opportunities for swimming and boating. It is in this context that they may be said to provide economic goods and services for current and future generations. The provision of these services is dependent on the inflow of freshwater into estuaries. The problem with estuarine freshwater demand is that estuaries are the ‘last in line’, literally and perhaps in the typical prioritisation of human wants by government. Clearly it is imperative that the value of freshwater inflows into estuaries be determined and these values incorporated into catchment management decision making. South African estuaries have in the past mainly been managed on a piecemeal basissometimes in the interest of fishermen, sometimes property development owners and sometimes other local interest groups. This situation changed with the National Water Act of 1998. One of its objectives was to address the mismanagement and inadequate research about water inflow impacts on estuaries (Allanson and Baird, 1999). The global warming phenomenon is going to negatively affect estuaries and put more pressure on the availability of freshwater inflows into estuaries, as well as the availability of drinking water. The majority of South African estuaries are temporally open/closed and experiencing reduced functioning due to reductions of freshwater inflow to them. Given the overwhelming evidence available on the significance of freshwater inflow to estuary functionality, it is clear that an important component of catchment management is the allocation of river water into estuaries. Economic guidance comes in the form of comparisons of value. There are seven estuaries for which values were generated, the Heuningnes, Kleinmond, Klein, Palmiet, Cefane, Kwelera and Haga- Haga. All of the seven estuaries fall in areas characterized by warm temperate climates and low rainfall levels. Estuary services, like many other environmental services, are not traded in the markets. For this reason, in order to estimate their value, reference must be made to proxy markets, and methods of valuation have to be employed that can use proxy market information - like the contingent valuation method (CVM), the travel cost method (TCM) and the hedonic pricing method (HPM). For the purpose of this research the CVM was preferred because it is best suited to including passive or nonuse values. The CVM estimated values are compared with other values generated using the TCM. The information required to make the CVs was gathered through surveys in at the seven selected estuaries from December 2005 to April 2006. From this information sample mean and median Willingness to Pay (WTP) values for freshwater were calculated, socio economic profiles were generated, the importance that respondents attached to various activities in the estuary was deduced, and, Tobit and Ordinary Least Squares (OLS) statistics models were used to predict household WTP. The Total WTP (TWTP) for each estuary was obtained by multiplying the median WTP by the total number of households that use the estuary. The median WTP is preferred to the mean WTP because of a skewed bid distribution of WTP among the users. The value per m3 of freshwater was obtained by dividing the TWTP by the total forecast reduction in water inflows into the estuary.

River flow is important in controlling phytoplankton distribution in estuaries. Data on the effect of river inflow on phytoplankton distribution patterns in temporarily open/closed estuaries is lacking. This study investigated the influence of river inflow on size-fractionated phytoplankton biomass (Chl a), community composition and environmental parameters measured monthly over three years in two temporarily open/closed estuaries in the Eastern Cape, South Africa. A once-off primary production study over an annual cycle was completed in the Van Stadens and Maitland estuaries. The study monitored physical, chemical and biological characteristics in both estuaries to examine the effects of changes in environmental factors and river inflow. Daily sampling of physico-chemical and biological variables from river to sea was carried out in the Van Stadens to investigate short-time scale effects of changes in environmental factors and river inflow on the phytoplankton biomass. Five and three stations in the main channel of the Van Stadens and Maitland estuaries respectively were sampled at 0.5 m below the water surface and 0.5 m above the sediment surface for biological and chemical variables and at the surface, 0.25 m and every 0.5 m thereafter for physical parameters. Five stations adjacent to the main channel along the estuary were monitored for groundwater macronutrient concentrations and five additional sites located within the upper catchment of the Van Stadens River were sampled on a quarterly basis over two years. Both estuaries were characterised by distinct hydrological conditions, an overwash, an open, a closed and a semi-closed mouth phase. Flooding in the Maitland and Van Stadens estuaries in 2001 and 2002 caused sediment scour, altered channel morphology and brought about breaching of the mouth. Flood driven mouth-breaching events occurred three and four times in each of the estuaries during the study. The mouth stayed open 20 – 25 percent and was closed 60 – 65 percent of the time. In the Van Stadens the closed overwash mouth condition occurred approximately 10 – 20 percent of the time while in the Maitland it occurred less with the semi-closed mouth condition occurring 10 – 20 percent of the time. Incidents related to mouth opening not associated with strong river floods occurred approximately 10 – 15 percent of the time, although in the Maitland a semi-closed mouth state persisted more frequently than in the Van Stadens Estuary. During flooding events salinity dropped to low levels (< 5 psu) but soon recovered to brackish conditions when river flow was reduced and marine water penetrated deep upstream. Reduction in river flow combined with marine sediment deposition resulted in the closure of the mouth. During closed mouth conditions strong onshore storm surges and spring high tides introduced marine water through overwash that kept salinity high. In both estuaries salinity showed a negative correlation with rainfall (R2 = 0.12), indicative of the strong influence of marine overwash that kept salinity high thus masking the influence of freshwater. High rainfall in the Van Stadens Estuary caused high levels of turbidity that reduced light penetration at depth. Light attenuation was positively correlated with the high rainfall (R 2 = 0.26) suggesting that increased turbidity was linked to rainfall induced discharge. In contrast, in the Maitland Estuary light attenuation did not show any correlation with increased rainfall possibly because of the reduced water depth and increased euphotic zone following the floods in 2002. High river inflow introduced macronutrients in both estuaries such that dissolved inorganic phosphates (DIP) and dissolved inorganic nitrogen (DIN) concentrations in the Van Stadens Estuary were strongly correlated with rainfall (R2 = 0.78 and 0.57 respectively). In the Maitland Estuary DIP and DIN concentrations remained significantly higher (p < 0.05) compared to that in the Van Stadens suggesting that the Maitland catchment contributed greater nutrient input into the estuary and may be associated with farming activities. Phytoplankton chlorophyll a (Chl a) ranged from 0.8 – 13.9 μg L-1 in the Van Stadens and in the Maitland Estuary from 5.3 – 138 μg L-1 during the 3-year study. During the open mouth condition Chl a biomass and primary production ranged from 5.4 – 52.9 μg Chl a L-1 and 1.2 – 11.7 mg C m-2 d-1 in the Maitland and in the Van Stadens from 1.6 – 9.8 μg Chl a L-1 and 1.2 - 14 mg C m-2 d-1 respectively. Maximum annual primary production in the Maitland and Van Stadens estuaries was 8.8 and 5.1 g C m-2 y-1 respectively. When the mouth was open in the Van Stadens Estuary the microphytoplankton (> 20 μm) accounted for > 65 percent of the Chl a, whereas during closed mouth conditions they accounted for about 55 percent of the Chl a biomass. Chlorophytes became the dominant taxon in the dry summer months but were replaced by cryptophytes and dinoflagellates during the wet season. When nutrient concentrations were low during low flow conditions in the Van Stadens Estuary mixotrophic microphytoplankton became an important fraction of the water column together with phototrophic dinoflagellates and cryptophytes. In the Maitland large sized chlorophytes were the dominant taxa in late spring and summer seasons and made up more than 80 percent of the cell numbers. In the Maitland before the floods in 2002 cyanophytes were the dominant group in late spring contributing more than 75 percent in cell abundance. Data from the short-term study in the Van Stadens Estuary showed similarities and differences in the Chl a response to increased river inflow. High river inflow initially reduced Chl a biomass followed by a recovery period of a couple of days compared to a 8 – 10 week recovery period in studies monitored over seasonal and annual temporal scales. The responses may be dissimilar but help to illustrate that there are similar response patterns to environmental forcing necessary to support phytoplankton biomass at different temporal scales. This study has demonstrated that flooding events caused by strong river flow cause breaching of the mouth, a reduction in salinity and marked nutrient input. Although the causes of flooding can be similar in both estuaries the resultant effects are varied and can alter the ability of the estuary to retain water. This study was able to demonstrate that the supply of macronutrients from the catchment was strongly correlated with rainfall (R2 = 0.67) and that phytoplankton growth mainly depended on an allochthonous source of macronutrients although internal supplies could be critical at times in controlling microalgal biomass.

South Africa, like the rest of the world, is vulnerable to the impact of climate change and loss of biodiversity. Water pollution is one of the six global threats to freshwater biodiversity. The future health status and productivity of South Africa’s estuaries is dependent on two main factors: management and quality and quantity of freshwater inputs. South Africa has around 250 functioning estuaries along its 3000 km coastline (Hosking 2004). They play an invaluable role in ecosystem functioning and biodiversity conservation. Estuaries are amongst the richest and most productive parts of the marine environment and as such call for careful management. Some of these ecosystems are focus areas for urban an industrial development. Urbanization and industrialization pose a serious threat to these sensitive systems. Increased water pollution from domestic use, industry and agriculture affect the ecology of these estuarine, river and lake systems. A large number of South African estuaries are still in excellent or good condition, but these are mainly the very small systems. The larger systems, like the Swartkops estuary, often very important in terms of conservation value, are also often compromised in some way or other. The reasons why they are compromised include habitat destruction, artificial breaching and pollution, especially those close to urban areas. This situation is aggravated by outdated and inadequate sewage treatment plant infrastructure and unskilled operators that dispose untreated waste into these systems. Pollution into estuaries can result in the partial loss of the environmental service flows supplied by them. The result of lost environmental service flows has adverse consequences, such as diminished residential and holiday recreational appeal, as well as reduced capacity to support subsistence livelihoods. Poor water quality not only limits its utilisation value, but is also places added economic burden on society, through both the primary treatment costs and the secondary impacts on the economy. Healthy estuarine ecosystems are essential for the maintenance of biodiversity and a wide range of environmental goods and services. Without a drastic improvement in water quality management approaches and treatment technologies, the continuous deterioration in water quality will decrease benefits and increase costs affiliated with use of these water resources.The market-based system of the South African economy has to a large extent failed to account for the value of the “free” goods and services provided by the natural environment. When the true value of the natural resources is unknown, there is a risk that less financial resources and capacity are made available to manage and protect these natural resources than is efficient. To ensure that these goods are properly taken into account, they must be valued and these values incorporated in social decision making. This study uses the contingent valuation method (CVM) to establish the value of the Swartkops estuary for changes to water quality. The CVM is a non-market valuation method that is widely used in cost-benefit analysis and environmental impact assessment. The CVM establishes the economic value of the good by asking the users of an environmental good to state their willingness to pay for a hypothetical scenario to prevent, or bring about, certain changes in the current condition of the environmental good. This method is subjected to some criticism. This criticism revolves around the validity and the reliability of estimated results and the effects of various biases and errors on them. The North Oceanic and Atmospheric Administration (NOAA) Blue-Ribbon panel investigating the validity of the CVM resolved that the CVM can be used to guide social decision making, if a series of guidelines are followed. The Swartkops contingent valuation (CV) was conducted with these guidelines in mind. The results of the Swartkops CV indicate that the user population has a total willingness to pay (TWTP) of R68848 (median bid) and R203632 (mean bid) annually for the implementation of a project to improve the water quality in the Swartkops estuary. User population is an important determinant of the TWTP value. As a result, using a more broadly defined user population, TWTP per annum was calculated to be R3481987 (median bid) and R10298688 (mean bid). Management of natural resources should be informed by values that reflect efficient balances, so as to obtain the most efficient use of them (Trupie 2008). Polluted water inflows into South Africa’s estuaries are a threat to their biodiversity. Healthy estuarine ecosystems are essential for the maintenance of biodiversity and human well-being (Water Assessment Programme Report 2006: 15). As a result, this study recommends that a project be implemented by the Nelson Mandela Bay Municipality to improve water quality in the Swartkops estuary.

An estuary is the last stage of a river. It is where the river meets the sea. Estuaries are one of the most significant features of the South African coastline. In recent years, South Africa has witnessed an increase in the demand for freshwater for both industrial and domestic purposes. At the same time, there has been a gradual deterioration of river systems and their catchments. To add to this, there has been a gradual reduction in the amount of recorded rainfall, which is the primary source of freshwater for rivers. This has resulted in decreased freshwater inflow into estuaries, a situation which poses a serious threat to the biological functioning of these estuaries and the services rendered to its recreational users. A deterioration of estuary services reduces the yield for subsistence households and their appeal for recration. This study uses the contingent valuation method as its primary methodology to elicit users' willingness-to-pay to reduce the negative impacts of reduced freshwater inflow into selected western and southern Cape estuaries. Eight estuaries were selected for this study; the Breede, Duiwenhoks, Great Berg, Kleinemond West, Mhlathuze, Swartvlei and Olifants estuaries. The contingent valuation (CV) method is widely used for studies of this nature because of its ability to capture active, passive and non-use values. The CV method involves directly asking people how much they would be willing to pay for specific environmental services. In this case, users were asked what they would be willing to pay to sustain freshwater inflows into selected estuaries in order to prevent the negative impacts of reduced inflows. The travel cost method (TCM) was uesed to generate an alternative comparative set of values for the purposes of convergence testing. This is because convergence testing is highly desirable as a validity test for CV estimates.

No description available.

Orientador: Wanilson Luiz Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-27T06:38:54Z (GMT). No. of bitstreams: 1 Volpato_Juliano_M.pdf: 8591527 bytes, checksum: 58b14d8c8d308419f349e7d957c88674 (MD5) Previous issue date: 2015 / Resumo: A existência de sedimentos altamente enriquecidos principalmente por Fe e P, provenientes das indústrias siderúrgica e de fertilizantes localizadas próximas ao estuário do rio Morrão, um dos principais receptores de efluentes industriais do Sistema Estuarino de Santos-Cubatão (São Paulo Brasil), juntamente com as condições físico-químicos do meio, constitui elementos especiais para avaliar se as condições formadoras de minerais como magnetita, hematita, pirita e vivianita podem ser influenciadas por contribuições químicas antrópicas. Este trabalho analisou as condições de formação desses minerais nos sedimentos superficiais do estuário do rio Morrão, na sua relação com a geoquímica dos sedimentos, condições físico-químicas, texturas sedimentares e conteúdo de matéria orgânica. A coleta de sedimentos de superfície consistiu em uma malha amostral de 10 x 10 m, em três transectos paralelos que cruzaram perpendicularmente o canal do rio Morrão. Os resultados mostraram que os sedimentos do rio Morrão encontram-se enriquecidos em diversos elementos químicos dentre os quais Fe, P, elementos terras raras (ETR) e vários metais-traço. O ambiente sedimentar do rio Morrão mostrou-se favorável à autigênese e coexistência de minerais como hematita, magnetita, pirita e vivianita. As fases minerais hematita e magnetita ocorrem amplamente no ambiente, já as fases minerais pirita e vivianita têm sua distribuição mais restrita. Os locais mais favoráveis à ocorrência de pirita e vivianita foram áreas de menor energia de fluxo, tais como planícies de intermaré lamosa, onde há altos teores de enxofre, ferro, fósforo, matéria orgânica e sedimentos finos / Abstract: The presence of sediments highly enriched by contaminant elements, mainly Fe and P, derived from a steel plant and fertilizer industries located near the Morrão River Estuary, the most anthropogenically influenced estuary of the Santos-Cubatão Estuarine System (São Paulo, Brazil), together with the environment physic-chemical conditions constitute special elements to evaluate if the forming conditions of mineral such as magnetite, hematite, pyrite and vivianite can be influenced by the anthropogenic input into the environment. This work studied the forming conditions of these minerals in the superficial sediments of the Morrão River Estuary in its relation with sediment geochemistry, physicochemical conditions, sedimentary texture, and organic matter content. The sample collection comprised a 10 by 10 meters grid composed of three parallel transects crossing perpendicularly the Morrão River channel. The results showed the sediments of Morrão River Estuary are enriched by several chemical elements among which Fe, P, REE and multiple trace elements. The sedimentary environment of the Morrão River showed to be propitious to the authigenesis and coexistence minerals such as hematite, magnetite, pyrite, and vivianite. Magnetite and hematite broadly occur in the environment, and pyrite and vivianite have restrict distribution. Moreover, the places more favorable to the pyrite and vivianite occurrence are areas with low water flux action, such as the intertidal mudflats, where concentrations of S, Fe, P, organic matter, and fine sediments are high / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

The objective of this research is to evaluate a coastal prediction system under various real world scenarios to test the efficacy of the system as a management tool in Tampa Bay. The prediction system, comprised of a three-dimensional numerical circulation model and a Lagrangian based particle tracking model, simulates oceanographic scenarios in the bay for past (hindcast), present (nowcast) and future (forecast) time frames. Instantaneous velocity output from the numerical circulation model drives the movement of particles, each representing a fraction of the total material, within the model grid cells. This work introduces a probability calculation that allows for rapid analysis of bay-wide particle transport. At every internal time step a ratio between the number of particles in each individual model grid cell to the total number of particles in the entire model domain is calculated. These ratios, herein called transport quotients, are used to construct probability maps showing locations in Tampa Bay most likely to be impacted by the contaminant. The coastal prediction system is first evaluated using dimensionless particles during an anhydrous ammonia spill. In subsequent studies biological and chemical characteristics are incorporated into the transport quotient calculations when constructing probability maps. A salinity tolerance is placed on particles representing Karenia brevis during hindcast simulations of a harmful algal bloom in the bay. Photobleaching rates are incorporated into probability maps constructed from hindcast simulations of seasonal colored dissolved organic matter (CDOM) transport. The coastal prediction system is made more robust with the inclusion of biological parameters overlaid on top of the circulation dynamics. The system successfully describes the basic physical mechanisms underlying the transport of contaminants in the bay under various real world scenarios. The calculation of transport quotients during the simulations in order to develop probability maps is a novel concept when simulating particle transport but one which can be used in real-time to support the management decisions of environmental agencies in the bay area.

Lionfish (Pterois spp.), an invasive species native to the Indo-Pacific, have permanently established themselves throughout the greater Caribbean, Gulf of Mexico, and regions of the Western Atlantic ranging from as far north as North Carolina to central Brazil. As their fundamental range expands, lionfish threaten to migrate into estuarine environments as they have been found to tolerate low salinities and an eclectic range of temperatures. The physiological capacity of invasion was assessed by quantifying the visual ecology of lionfish utilizing corneal electroretinography (ERG) as well as their metabolic scope and hypoxia tolerances under various temperature-oxygen-regimes utilizing intermittent-flow respirometry. Seasonal changes in temperature-dissolved oxygen levels consistent with Atlantic/Gulf of Mexico inshore estuaries not only exceed the physiological tolerances of lionfish, but also constrain metabolic scope at sub-lethal levels by significantly limiting maximum metabolic rate across all temperatures. Median Scrit values were 33%, 39%, 46%, and 54% at 15, 20, 25, and 30℃ respectively. Luminous sensitivities, temporal resolutions (Flicker fusion frequency), and spectral sensitivities scaled similarly with other estuarine piscivores indicating lionfish possess a visual system that can function effectively within estuarine photic conditions. Overall, visual characteristics of estuaries will not pose as a significant barrier to lionfish, but minimum winter temperatures and hypoxia will pose controlling and limiting factors substantially preventing further inshore invasion. However, caution should still be advised as lionfish may capitalize on specific temporal and spatial scales that provide suitable habitat quality and abundance of prey items. Further insight is needed to forecast the effects of temperature-dissolved oxygen on lionfish metabolic-scope.