Thesis advisor: Gail Kineke / Thesis advisor: Noah Snyder / Salt marshes are some of the world’s richest ecosystems and provide a plethora of benefits to coastlines and bays in terms of storm protection and chemistry. To ensure salt marsh survival under increasing rates of sea level rise, management practices have been trending towards natural sustainability measures to increase marsh resilience. To benefit these efforts, it is necessary to understand how natural salt marshes respond to environmental change in terms of sediment deposition and evolution of vegetation and open water. This study uses aerial image digitization to understand how Nauset Marsh in Cape Cod MA, a protected salt marsh on Cape Cod National Seashore, has responded to sea level rise and half a century of inlet migration. Digitized images from 1974-2019 were used to track changes to vegetation extent and open water features during study periods of different inlet migration stages. Observed changes were used to ascertain trends of marsh loss or adaptation based on previous research on ponding cycles and vegetation extent. Results indicate that Nauset Marsh has been relatively stable over the last half century, with the most significant change observed in Vegetated Marsh loss of 6.71% ± 3.19 primarily due to edge erosion near the present-day inlet. Despite net feature stability, significant differences in feature evolution trends were observed during different stages of inlet migration. Most notably, inlet breaching and migration correlated with dynamic feature changes throughout the marsh, while the static inlet period correlated with expansion of open water features near the inlet location. The evolution of Nauset Marsh suggests that inlet migration improves marsh resilience through periodic increases in sediment deposition in a natural salt marsh with sufficient sediment supply. / Thesis (MS) — Boston College, 2023. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

<p> This thesis describes the study of plate vortex ring generators invented and developed by Latta and modified and constructed by E.S.Fox. The vortex ring generator has been applied to destratify and aerate a natural pond in this research. Experiments were conducted to mix and aerate a stagnant and stratified pond in a natural, outdoor setting. Mixing times, temperatures, dissolved oxygen, BOD, COD and pH were measured for each experiment trial. A fluctuating single plate vortex ring generator was constructed and used in four of the five experiments with the depth of the vortex ring plate varied to determine the effect on mixing and aeration. A final experiment used a dual plate vortex ring mixer to examine the advantages of multiple plates with regard to mixing and aeration as well.</p> <p> It was found that the single plate vortex ring generator with an operating range of 1 /2 to 4/5Hz effectively destratified and mixed the pond within a 12 hour mixing duration. The generator aerated the pond by establishing a flow pattern in the pond such that the water at the surface of the pond experienced increased contact with the atmospheric air thereby transferring oxygen to the water. The impact of atmospheric air temperature proved to be a significant factor as a heat source to the pond which affected the time taken to destratify the pond. The increased oxygen transferred to the pond increased dissolved oxygen in the pond. The microbial organisms present in the pond experienced increased activity due to the increased dissolved oxygen available in the water because of the mixing action provided by the vortex ring generator.</p> <p> The summary of calculated results for all five experiments with the vortex ring mixer is as follows: (Refer to page iv for chart). <p> On the basis of the experimental results it was determined that the vortex ring generator has a bright future as a tool to improve water quality in natural water courses.</p> / Thesis / Master of Engineering (ME)

No description available.

In present thesis we study and describe a stochastic loss reserve model for individual insurers. Specifically, it is the model based on the three following features. Modelling of expected claims depends on unknown parameters which estimates need to be the most accurate. Aggregated occurred and paid losses for particular years are modelled by a collective risk model. The final reserve is estimated by Bayesian methodology that uses a prior information from a significant number of insurers. Part of the thesis is also an implementation of the program that calculates reserves by using our model and its testing on simulated data.

The Murray cod (Maccullochella peelii peelii Mitchell 1838) is Australia�s largest freshwater fish. Once highly abundant in the Murray-Darling river system, populations have drastically declined in recent decades. Many causes for this decline have been proposed, including over-fishing, habitat loss and altered river flow regimes. This study hypothesised that elevated salinities have led to selective mortality in some developmental stages, which have in turn depleted stock recruitment and adult populations. The objectives of this study were to determine the optimal, threshold, upper sublethal and lethal salinities for development of eggs, yolk-sac larvae, fry and fingerlings of M. peelii peelii. Investigation the impact of salinity on fertilisation utilised gametes of trout cod (M. macquariensis, Cuvier 1829) instead of M. peelii peelii. Studies were carried out in a controlled laboratory environment using test media prepared from commercial sea salt. The results showed that the eggs of the trout cod hatched only when fertilised and incubated in freshwater, and only larvae hatched in freshwater survived through the yolk absorption period of 12 days. Yolk utilisation efficiencies were not significantly different among the salinities of 0-0.30 g/L. There was no effect of pre- or post- fertilising processes on the salinity tolerances of yolk-sac larvae. No larvae survived at salinities higher than 0.30 g/L during the yolk utilisation period. Lethal salinity concentration in Trout cod and Murray cod larvae was exposure time dependent. The 1 day LC50 of the larvae was 1.97 and 2.33 g/L respectively, compared with the 12 day LC50 values of 0.50 and 0.35 g/L respectively. The threshold (no effect level) salinities of larvae of Trout cod and Murray cod were 0.46 and 0.34 g/L respectively at 12 days exposure. The salinity sensitivities of fry of Murray cod were moderated by increasing pH between pH 6.2 and 8.8, and stimulated by increasing temperatures from 15 to 30°C. The optimal salinity was only slightly affected by temperature. The threshold and upper sublethal salinities varied slightly depending on feeding regime. The salinity sensitivities of fingerlings of Murray cod were: LC50 = 13.7 g/L; optimal salinity from 4.6 to 5.0 g/L ; threshold salinity from 5.9 to 7.4 g/L, and upper sub-lethal salinity from 9.2 to 9.9 g/L � with the range in all cases affected by acclimation period salinity. The blood osmolality at LC50 of the fingerlings was 444 mOsmol/kgH2O or equivalent to 14.2 g/L, and the dehydration rate was 4.8%. The osmolality increased significantly in salinities higher than 9.0 and 6.0 g/L when fish were exposed for a period of 1 day and 41 days respectively. The oxygen consumption increased significantly in salinities higher than 8.0 g/L. Distortion of the notochord and corrosive skin syndrome were major symptoms describing sub-lethal effects found in the embryos, and fry and fingerlings of Murray cod respectively. Noting the risks of extrapolating directly from laboratory to field conditions, it is predicted that when salinity in natural habitats increases above 0.34 g/L a significant impact on Murray cod recruitment will result.

Atlantic cod (Gadus morhua L.) is one of the most promising new fish species introduced to cold water aquaculture due to the large established market in Europe and the USA and the decline in wild stock. So far, the production of farmed cod has been relatively low, with the main hindrance due to diseases. Vibrio anguillarum has been recognised as the biggest disease problem of farmed cod and has slowed the development of a successful cod aquaculture industry. When the first incidences of V. anguillarum occurred in cod aquaculture, vaccines designed for vibriosis in Atlantic salmon (Salmo salar L.) were used in an attempt to combat the disease. However, these vaccines did not provide sufficient protection, possibly because they lacked serotype O2b, which is known to affect cod and to a lesser extent salmonids. Recently, vibriosis vaccines specifically designed to protect Atlantic cod have been formulated, but outbreaks of vibriosis in vaccinated fish are still being reported, suggesting that these formulations are inadequate. The aim of this project was to develop a whole cell inactivated vaccine formulation specifically tailored to protect Atlantic cod against Vibrio anguillarum. The serological classification of V. anguillarum was first investigated by producing a set of monoclonal antibodies (mAbs). Using lipopolysaccharides (LPS) extracted with butan-1-ol, 4 mAbs were selected and shown to react specifically with V. anguillarum serotypes O1, O2a and O2b. A collection of over 150 V. anguillarum isolates were screened using these, which revealed that most of the isolates had been previously correctly classified. A new sub-serotype of V. anguillarum O2 was identified from isolates recovered from outbreaks of vibriosis in Norway as well as Scotland. This new sub-serotype was referred to as O2d since the subserotype O2c has been recently identified in vibriosis cases from Atlantic cod. However, it was shown that the O2c sub-serotype might not belong to the O2 serotype, but in fact belongs to another serotype. To protect Atlantic cod against all the V. anguillarum serotypes (and subserotypes) which they are susceptible to, it is recommended that isolates from serotypes O1, O2a, O2b, O2c and O2d should all be included in a bacterin vaccine for cod. In order to determine which isolates from each of the serotypes to include in the vaccine, a variety of virulence factors of V. anguillarum were investigated in vitro. The interaction of some candidate isolates from O1, O2a and O2b serotypes (O2c and O2d were not identified at the time this part of the study took place) with cod phagocytic cells were studied using flow cytometry. Phagocytosis and respiratory burst of cod macrophages and neutrophils as well as cod serum killing of V. anguillarum were quantified. It was found that isolates within the same serotype displayed varying degrees of resistance to phagocytosis and the subsequent respiratory burst activity as well as that all the V. anguillarum strains tested were resistant to Atlantic cod serum killing. These in vitro assays were found to be very useful in assessing the virulence of V. anguillarum. The isolate within each serotype eliciting the highest percentage of positive phagocytic cells was selected in order to increase the antigen presentation pathway, thus theoretically enhancing the protection elicited by the vaccine. A multivalent formalin-inactivated non-adjuvanted vaccine was prepared which included all the serotypes previously described and was injected intraperitoneally into Atlantic cod. A bath challenge was performed on vaccinated and mock-vaccinated fish, 6 weeks post immunisation, using V. anguillarum isolates from the serotypes O2b, O2c and O2d that were not included in the vaccine. An excellent level of protection was obtained against O2b and O2d (relative percentage survival 100% and 96.4%, respectively), but the challenge with the sub-serotype O2c isolate did not produce any mortality in the control group and needs to be repeated. The vaccine formulation was very efficient at protecting Atlantic cod against vibriosis but further challenges need to be performed with other serotypes included in the vaccine (O1 and O2a), as well as with more isolates from the O2b, O2c and O2d sub-serotype. To conclude, Atlantic cod is a species which will certainly have a major influence in marine aquaculture, but many areas have to be improved. The development of an effective and broad range vaccine to protect cod against Vibrio anguillarum offers another advance which should help Atlantic cod aquaculture to reach its full potential.

In Scotland, environmental regulation restricts commercial cod culture to the equivalent of 66 % of that granted for commercial Atlantic salmon (Salmo salar L.) farms. This calculation is based on estimations of nitrogen discharge from the difference in protein content between salmon and cod diets, with the higher levels of protein in cod diets suggesting a higher nitrogen discharge compared to that observed for salmon diets. In turn, this could potentially result in increased nitrogen enrichment of a marine ecosystem. The aims of this study (quantifying and modeling of nitrogenous wastes associated with the commercial culture of Atlantic cod (Gadus morhua L.) were achieved through a series of tank and cage investigations, each of which studied juvenile and adult Atlantic cod. The study provided data with respect to nitrogen excretion from juvenile and adult fish in both systems. This would allow the development of dispersion models and the calculation of nitrogen budgets for commercial cod culture, thus providing environmental regulators data independent of salmon models to create regulations that would be specifically applied to cod farming. The tank - based studies investigated three diet formulations produced by EWOS® Innovation in Norway, as a 4 mm pellet (juvenile study) and as a 7 mm pellet (adult study). The three iso -energetic diets varied primarily in protein content (40%, 50% and 60%). Two tank studies, one on juvenile and one on adult cod, investigated growth, condition and tissue composition, and the production of dissolved nitrogenous wastes over a 5 and 7 month period respectively. At the beginning of the acclimation period prior to the adult tank study commencing, the fish had a mean weight of approximately 1275 g. The difference in the final weight promoted by each diet was not significant (with an approximate final weight of 2400g), suggesting that a low protein diet (40 % protein) promoted similar growth to a high protein diet (60 % protein). Other growth and condition parameters were also similar for all diets with the condition improving over the course of the study. As the fish completed spawning immediately prior to the commencement of the study, an increase in condition was not observed until approximately day 90 of the 210-day investigation. Over the course of the 5-month juvenile study, growth was approximately 224g for the 40% protein diet and approximately 275g for the 50% protein and 60% protein diets. This suggests that a higher protein diet is required for optimal growth of juvenile cod and that 50 % and 60% protein diets promote similar growth and condition, potentially reducing the protein requirement of juvenile diets. In the juvenile investigation, condition increased over the full range of the study. In both tank studies, nitrogen digestion was directly related to protein (and associated nitrogen) content of the diets in the juvenile study expressed as a percentage of the nitrogen content of the diet as 59.19% (40% protein), 56.90% (50% protein) and 52.23% (60 % protein) suggesting that nitrogen digestion is more efficient at lower protein content in the diet. When expressed as a percentage of the nitrogen content of the diet, nitrogen digestion observed in the adult study was 60.55%, (40% protein) 60.92% (50% protein) and 60.60% (60% protein) respectively, suggesting protein digestion is similar regardless of protein content in adult cod. In the adult tank study, under a manual feeding regime, a post-prandial-peak is observed at 105 min. following the cessation of feeding. Thereafter, ammonia levels drop over the course of the sampling period. Following the afternoon meal commencing at 420 min., ammonia levels rise at least until the final samples are collected at 450 min. Under an automated regime, a lesser post-prandial-peak is observed but the ammonia concentration is lower over the sampling period compared to the respective profile under a manual regime. The ammonia profile produced throughout the juvenile tank study follows a very similar trend to that observed in the adult study under the manual feeding regime. Two cage - based investigations took place at the No Catch® Ltd. commercial organic cod farm in Vidlin Voe on the east coast of Shetland. Both studies investigated growth, condition and tissue composition, as well as the production of dissolved nitrogenous and particulate wastes associated with the culture of juvenile and adult Atlantic cod in cage systems. Sampling for the adult study occurred over three days during three sampling trips (September 2005, November 2005 and February 2006). Sampling for the juvenile study took place over three days on a single trip to Vidlin in late April 2006. The diets used at No Catch® Ltd. were produced by Biomar® in Grangemouth. A relationship between feeding and ammonia concentration is less evident in the cage studies than in the tank studies, and similarly, the relationship between feeding and ammonia concentration is less evident in juvenile fish than in adult fish. As ammonia values were converted to (µg/L/tonne biomass), the ammonia concentration recorded is largely dependent upon the biomass of the sampled cages at both the nursery site and production site. Deposition rates of organic carbon and nitrogen around the production and nursery cage sites in Vidlin Voe are related to the position of the sediment trap relative to its location and proximity of the trap to the specific cage site. Weather condition also had an impact on deposition rates with calmer weather producing lesser deposition rates. Around the production site, deposition rates of organic carbon and nitrogen are greatest in the direction of the prevailing current. Deposition rates decrease with an increasing distance from the cages. Although sediment trap results were inconsistent, a similar trend is observed for each of the three sampling trips, although actual deposition values were different. Differences between the deposition rates at the highly dynamic production site and the low energy nursery site indicated that sedimentation of waste from cod culture is highly dependent on water currents. Models of particulate waste deposition associated with the production cage site in Vidlin Voe were produced using the spreadsheet - based Cage Aquaculture Particulate Output and Transport (CAPOT) model, developed at the Institute of Aquaculture. The models were parameterised using the data collected and tested against an established regulatory model, DEPOMOD. The similarity in results illustrated the robustness of the highly flexible spreadsheet waste model for cod culture.

Pappersbruken har två pappersmaskiner, PM4 som tillverkar mjukpapper från returfiber och PM13 som tillverkar papper till transformatorer och kablar från oblekt barrsulfatmassa. Överskottsvattnet från PM4, PM13 och returfiberanläggningen samt dagvattnet leds vidare till den externa avloppsreningen. Då någon utav pappersbruken har driftsstop erhålls ojämna utfall främst för pH och COD. Syftet med projektet är att kartlägga pH och COD förändringen i de enskilda delstegen i processerna PM 4, PM 13 samt den externa avloppsreningen. Det genomfördes intensiv provtagning från tolv provtagningspunkter i trettiotvå dagar. Prover analyserades samma dag med avseende på pH, konduktivitet, alkalinitet, COD, suspenderade ämnen och glödrester. Dessutom utfördes fällningsförsök på inkommande processavloppsvatten med styrd dosering av järnsulfat, järnklorid och aluminiumsulfat. Det genomfördes även metodvalidering, kalciumbestämning, samt försök med sammanblandat avloppsvattenprov. Resultat från mätningarna visar att processlinje PM 4 har generellt sätt högre pH-, konduktivitet-, alkalinitet - och COD värden och högre halt glödrester, men lägre halt suspenderade ämnen än PM 13. Det konstaterades att den största förändringen i de två processerna sker strax innan och efter pappersmaskinen. Efter pappersmaskinen, i det vattnet som leds vidare till den externa avloppsreningen, erhålls 70% COD reduktion och en pH ökning på 0,75 pH ekvivalenter för PM 13, respektive 30% COD reduktion och en pH sänkning  på 1,27 pH ekvivalenter för PM 4. Totalt sätt, tyder resultat på att den största pH förändringen sker vid avloppsreningen, med 1,74 pH ekvivalenter. Från fällningsförsöken konstateras det att bästa pH- och lägsta COD- värden erhålls för fällningsmedlen, järnklorid och järnsulfat vid lägsta doseringsmängder, d.v.s. 97 g/m3 respektive 101 g/m3, utan pH justering. Resultat från jämförelse mellan processavloppsvatten och sammanblandat avloppsvatten, där dagvattenpåverkan utesluts tyder på 0,01-0,86 högre pH-värden i dem sammanblandade avloppsvattenprover. Alltså finns det en antydan att dagvatten bidrar till pH sänkning i ingående processavloppsvatten. För att åtgärda problemen borde järnklorid utprövas i lägre doseringsmängder i kombination med minskad svavelsyretillsats. Eventuellt kan järnklorid bytas ut mot järnsulfat. Installera mätinstrument för mätning av pH och COD direkt på det ingående- och utgående vattenflödet i den externa avloppsreningen för att möjliggöra exakt dosering av fällningskemikalierna utifrån dessa värden. Dagvattnet borde avskiljas från avloppsreningen och istället avledas till det kommunala avloppsnätet. / The paper mills have two paper machines, the PM 4, producing tissue from the RCF and the PM 13, producing paper for transformers and cables from the unbleached softwood craft pulp. Excess water from PM4, PM13 and RCF factory, together with the storm water, leads on to the external wastewater treatment. When any of the paper mills has downtime, unequal outcomes are obtained, primarily with respect to pH and COD. The aim of the project is to identify the individual steps in the processes PM 4, PM 13 and wastewater treatment re to the pH and COD changes. Intensive sampling was carried out from twelve sampling points during thirty-two days. These samples were analyzed on the same day re to the pH, conductivity, alkalinity, COD, suspended solids, and inorganic residue. In addition, precipitation tests were carried out on the incoming wastewater with controlled doses of the ferrous sulphate, ferric chloride and aluminium sulphate. In addition methodological validation, calcium determination, and experiments with the mixed wastewater samples were carried out. The results show that the process line PM 4 has generally higher pH, conductivity, alkalinity, COD and concentration inorganic residues, but has a lower content of suspended solids than PM 13. But the biggest difference in the two processes takes place just before and after the paper machine. After the paper machine, the water that goes on to the external wastewater treatment, where a 70% COD reduction and a pH increase of 0,75 pH equivalents for PM 13, and 30% COD reduction and a pH decrease of 1,27 pH equivalents for the PM 4 are obtained. The results suggest that the greatest pH change occurs in wastewater treatment, with 22.06%. From precipitation experiments it was found that the best pH values and lowest COD values where obtained for precipitation chemicals, ferric chloride and ferrous sulphate at the lowest dose levels, i.e. 97 g/m3 and 101 g/m3, without pH adjustment. Results from the correlation between wastewater- and mixed wastewater samples, which excludes impact of storm water, indicates that pH values are 0.01 to 0.86 pH equivalents higher in those mixed wastewater samples. Thus, there is a hint that the storm water contributes to pH reduction of the input wastewater. To address these concerns ferric chloride should be tested at lower dose levels combined with reduced sulphuric acid addition. Eventually ferric chloride may be replaced by the iron sulphate. In addition, there should be measuring devices for pH and COD installed on the process wastewater and outgoing water, in the external wastewater treatment in order to allow for accurate dosing of chemicals precipitate from these values. Storm water should be separated from wastewater treatment and instead be diverted directly to the municipal sewage system.

Munksunds pappersbruk är ett integrerat massa- och pappersbruk som består av två fiberlinjer, en barr- och en lövlinje där båda kokarna är kontinuerliga med efterföljande tvättsteg. En kartering av COD (eng. Chemical Oxygen Demand) och natrium utfördes för båda linjerna för att utvärdera tvätteffektiviteten. COD anger hur mycket syre som krävs för att bryta ned det kvarvarande organiska materialet och natrium används som en indikator på tvättförlusten av kokkemikalierna. Karteringen utfördes genom att analysera in- och utgående flöden vid varje tvättsteg, exklusive kokarna. En förenklad metod användes, där tre flöden analyserades och den fjärde beräknades genom flödes- och massbalanser. Modellen som användes för att beskriva tvätteffektiviteten för respektive utrustning var tvättutbytet Y, som erhölls genom en massbalans. Studien visade att halten COD och Natrium minskar mest från början för respektive linje och når ett gränsvärde runt 8,2 kg COD/adt och 6,6 kg Na/adt för barrlinjen, respektive 8,5 kg COD/adt och 4,8 kg Na/adt för lövlinjen, där ytterligare substans inte kan tvättas bort. Båda linjerna tvättar likvärt med avseende på COD, men lövlinjen tvättar bättre med avseende på natrium. I det sista tvättsteget hade båda fiberlinjerna eliminerat 98% av den inkommande COD-mängden med massan från kokarna. Vidare hade barrlinjen eliminerat 86% och lövlinjen 93% med avseende på natrium i det sista tvättsteget. Utvärderingen av de olika tvättutrustningarna visade att DD-filtret i lövlinjen var effektivast både med avseende på COD och natrium, följt av PO-pressen. På barrlinjen var filter 1 mest effektivt med avseende på COD och natrium. / A mapping of COD (Chemical oxygen demand) and sodium will be done to evaluate the different washing steps. COD describe the amount of oxygen needed to dissolve the organic matter left in the pulp and sodium is used as an indicator of the washing loss of the cooking chemicals. The in- and outgoing streams of the washing steps was analyzed to examine the efficiency. A simplified method was applied where three streams were analyzed and the fourth was calculated through flow-and mass balances. The model used to describe the wash efficiency in this study was the wash yield, which can be obtained by mass balances. The study showed that the content of COD and sodium decreased most in the beginning and reaches a limit value of 8,2 kg COD/adt and 6,6 kg Na/adt in the softwood pulp line and 8,5 kg COD/adt and 4,8 kg Na/adt in the soft wood pulp line, where no more content could be removed. Both pulp lines washed efficient with aspect of COD, but the hardwood pulp line washed more efficient in the aspect of natrium compared to the softwood pulp line. In the last washing step, both pulp lines had removed 98% of the ingoing COD from the digester. With aspect to natrium the softwood pulp line had removed 86% and the hardwood pulp line 93% in the last washing step. The evaluation of the different washing equipment showed that the DD-filter in the hardwood pulp line was the most efficient with aspect of both COD and Sodium, followed by the PO-press. In the softwood pulp line, filter 2 was the most efficient regarding both COD and Sodium. The flow- and mass balances turned out to be complicated at some of the washing steps, especially around the Q1-press in the hardwood pulp line and press 1-3 and filter 2 in the softwood pulp line. The reason for this could be that different functional chemicals are added before the Q1-press, which was not considered in this study, additional causes could be unidentified flows that affect the balances. The study was limited to only analyze three streams and calculate the fourth, an analyze of all the streams would give a more accurate result. However, the study provides a good overview of the wash efficiency in the pulp mill.

In this project, an investigation of a neural network based system is used to examine the following: a) the possibility and practicability of analysing and recognising parasites/sealworms on a parasite/sealworm infested cod fish images, b) the most efficient but robust way of presenting data to the neural network for efficient training and generalisation. The basic problem is to automate the sorting of sealworm infested cod fish from good normal cod fish using a neural network based system. The generalised back propagation supervised learning algorithm is used and both steepest descent and conjugate gradient methods are investigated. Various data representation schemes in unprocessed and processed formats before presentation for training of the neural network, are also examined. Finally the level of recognition achieved by the neural network when presented with the cod fish images is computed. Thus in this project an attempt is made to analyse and find the best components for solving the basic problem and then use this information to develop a neural network based system to recognise, detect and locate parasite/sealworms on cod fish images. / Thesis / Master of Science (MSc)