Diante do quadro atual de previsões de mudanças climáticas, estudos a respeito das possíveis respostas dos organismos a estas alterações são importantes. Com a finalidade de prever e verificar se estas serão de fato deletérias ou se os organismos são capazes de lidar com elas sem alterações na sua fisiologia, e consequentemente na estrutura do ambiente, E. brasiliensis foi utilizada como modelo para estudar possíveis impactos do aumento da temperatura e acidificação dos oceanos na sua fisiologia. Para isso, espécimes foram expostos a 9 possíveis combinações de temperatura (24ºC, 28ºC e 30ºC) e pH (8.0, 7.7 e 7.3) em diferentes intervalos de tempo (1, 3, 12, 24 e 48 h). Amostras de gônadas e fluido celomático foram coletadas para avaliar a expressão das proteínas de estresse HSP70, AIF-1 e p38-MAPK, e a variação no número e viabilidade dos celomócitos. Nossos resultados mostram que o modelo é sensibilizado pelas mudanças no ambiente, através da hiper-regulação das proteínas de estresse. O cenário considerado mais extremo (30°C + pH7.3) ocasionou a morte de 100% dos organismos após 24horas. E o segundo cenário mais severo (30°C + pH7.7) desencadeou o desenvolvimento de ulceração de pele. Os efeitos são mais pronunciados nos celomócitos e a acidificação da água parece ter efeitos antagônicos com a temperatura nos celomócitos e sinérgicos nas gônadas. Embora a resposta tenha sido sistêmica, o grau e a dinâmica foram distintos em relação às diferentes amostras e estresses. Podendo causar modificações na resposta imune dos organismos e consequentemente na sobrevivência da espécie a longo prazo. / Under the current Climate Change context, studies about the potential responses of the organisms to their changing environment are of extreme importance. Recent studies point out the synergy of temperature and ocean acidification altogether. In this study, we used the sea star E. brasiliensis to assess the physiological effects of rising temperature, seawater acidification and the interaction of both factors. Independent individuals (N=225) were exposed to 9 possible combinations of temperature (24ºC, 28ºC and 30ºC) and pH (8.0, 7.7 and 7.3), for 1, 3, 12, 24 and 48 h. We compared the stress produced by these treatments measuring the expression of heat shock proteins (HSP70), the production of the allograft inflammatory factor (AIF−1) and the activation of mitogen kinases (MAPKs) at both gonad and celomic fluid. Furthermore, we assessed the quantity and quality of coelomocytes. Our results demonstrated that E. brasiliensis is vulnerable to the interaction of temperature and acidification. All the stress proteins evaluated were upregulated. The extreme scenario (30°C + pH7.3) caused the death of 100% of organisms after 24 hours, while the second most severe scenario (30°C + pH7.7) triggered skin ulceration. Nevertheless, we found that water acidification produces antagonistic effects to the temperature in coelomocytes and synergistic effects in gonad cells. Furthermore, these effects were more pronounced in the coelomocytes than in the gonads. The systemic response found in this study suggest that the interactive effects of elevated temperatures in conjunction with ocean acidification may endanger the survival of this species, and it could compromise the ecosystem functioning at long term.

Este projeto de pesquisa foi desenvolvido visando quantificar possíveis distúrbios de vazão em emissores do tipo gotejador (irrigação localizada) submetidos à aplicação de cloro livre e acidificação em condições estática e dinâmica de fluxo de água no sistema. O experimento foi realizado no período de setembro de 2005 a junho de 2006, utilizando-se 14 modelos de gotejadores autocompensantes com suas respectivas linhas gotejadoras montadas em uma bancada de ensaios em estrutura metálica. Os tratamentos utilizados no experimento foram: a) aplicação dinâmica de 100 mg L-1 de cloro livre com pH na faixa de 5,5 a 6,0; b) aplicação estática de 100 mg L-1 de cloro livre com pH na faixa de 5,5 a 6,0; c) aplicação de ácido nítrico com pH na faixa de 2,0 a 3,0 durante ½ h (sistema pressurizado); d) aplicação de ácido nítrico com pH na faixa de 2,0 a 3,0 durante 12 h (sistema pressurizado). Foram realizadas curvas vazão versus pressão para cada tratamento em três diferentes temperaturas da água (15, 25 e 40° C). O delineamento experimental utilizado foi o inteiramente aleatorizado em esquema fatorial, com utilização dos testes ?F? para análise de variância e Tuckey, a 5% de significância, para comparação de médias e análise de regressão. Os resultados obtidos mostram que para o tratamento da água com 100 mg L-1 de cloro livre em condição dinâmica, ocorreu um decréscimo de 10 a 20% em média da vazão (L h-1) para alguns modelos de gotejadores mais sensíveis aos produtos químicos, sendo que o modelo I apresentou redução drástica de vazão na ordem de 100% em virtude do bloqueio total do labirinto do emissor, em decorrência do aumento de 112% do volume da membrana após 2688 h de aplicação contínua de cloro. Os tratamentos estáticos não apresentaram variações acentuadas de vazão média (L h-1), coeficiente de variação (%), uniformidade de distribuição (%), Vazão Relativa (%) e Grau de Entupimento (%). Verificou-se relação linear entre a vazão e a temperatura da água para os gotejadores novos, sendo que após a aplicação dos diferentes tratamentos, as curvas vazão versus pressão para cada modelo de gotejador sofreram influência tanto da pressão quanto da temperatura de maneira distinta. / This research project was developed to quantify possible flow rate variation in emitters (drip irrigation) submitted to the application of free chlorine and acidification under static and dynamics conditions of water flow. The experiment was accomplished in the period of September, 2005 to June, 2006, being analyzed 14 models of pressure compensating emitters set up in a metallic bench. The treatments used in the experiment were the following ones: a) dynamic application of 100 mg L-1 of free chlorine with pH 5,5 to 6,0; b) static application of 100 mg L-1 of free chlorine with pH 5,5 to 6,0; c) application of acid nitric with pH 2,0 to 3,0 during ½ h (pressurized system); d) application of acid nitric with pH 2,0 to 3,0 during 12 h (pressurized system). The operating pressures and emitter model combination were: 50, 100, 200, 300, 400 kPa for emitters A to N, in three different water temperatures (15, 25 and 40° C). The obtained values of flow rate were used to calculate the CUD, CV, relative flow rate, the percentage of drippers in each flow rate range, and the number of the drippers completely clogged. The statistical analysis of the treatments were accomplished by Tukey test at 5% probability. The obtained results show that for the treatment of the water with 100 mg L-1 of free chlorine in dynamic condition, a reduction from 10 to 20% of the flow rate (L h-1) occurred for some models more sensitive to chemical products. Model I presented drastic reduction of flow rate in the order of 100% by total blockade of the labyrinth of the emitter, due to the increase of 112% of the volume of the membrane after 2688 h of continuous application of 100 mg L-1 of chlorine free with pH 5,5 to 6,0. The static treatments didn\'t present accentuated variations of medium flow rate (L h-1), variation coefficient (%), distribution uniformity (%), relative flow rate (%) and degree of blockage (%). For pressure compensating emitters, where the discharge sensitivity to temperature is insignificant, after the application of the different treatments, the measured discharge/pressure relationship for each emitter model was sensitive to pressure as well to temperature.

Arsen im Trinkwasser und in der Nahrung stellen regional bedeutsame Probleme dar. Die Abschätzung der Dimension und eine wissenschaftliche Klärung der Ursachen sind Voraussetzung für den Schutz von Mensch und Natur. Mit dem Speicher Altenberg wurde ein Trinkwasserspeichersystem untersucht, in dem erhöhte Arsenkonzentrationen zu beobachten sind. Ziel der Untersuchungen waren Erkenntnisse über eine mögliche Fortsetzung des bisher beobachteten Trends zu steigenden Arsenkonzentrationen. Hierzu wurde das System in Kompartimente unterteilt und diese auf ablaufende Prozesse und Dynamiken untersucht. Das System besitzt eine geringe Produktivität auf Grund von Nährstoffarmut, insbesondere einer Phosphat-Oligotrophie. Es ist, wie viele Gewässer in der nördlichen Hemisphäre, im Kontext sinkender Immissionsbelastungen wie auch des Klimawandels von hohen und zunehmenden Huminstoffeinträgen aus dem Einzugsgebiet geprägt. Hinzu kommt das Wirken von internen und externen Arsenquellen. Am Grund der Gewässer wurden arsenreiche und humose Substrate nachgewiesen. Sie sind einerseits die Folge einer lang anhaltenden Akkumulation von Sedimenten, die auf Einträge aus dem von arsenreichen Grundgesteinen und anmoorigen Böden geprägten Einzugsgebiet zurückgehen. Andererseits kommt eine Überstauung anmooriger Böden und Moore mit gespeichertem lithogenen bzw. chalkogenen Arsen am Baugrund der Speichergewässer in Frage. Die Bedeutung deponierter Flugaschen wird für das System als untergeordnet eingeschätzt. Für den im System als Vorsperre genutzten Galgenteich zeigt sich seit Beginn der Arsenmessungen im Jahre 1997 ein bis zum Jahre 2000 andauernder stetiger Anstieg der Arsenkonzentration, der statistisch signifikant mit einem Rückgang der Nitratkonzentration einhergeht. Diese ist ihrerseits Teil eines allgemeinen Trends einer ökologischen Regeneration mitteleuropäischer bewaldeter Wassereinzugsgebiete seit Ende der Achtzigerjahre in der Folge abnehmender Depositionslasten. Die wahrscheinlichste kausale Verknüpfung zwischen beiden Parametern ist eine Änderung des redoxchemischen Milieus der Gewässersedimente. Zu Zeiten der hohen Depositionen unterdrückten hohe Konzentrationen von Nitrat als sekundärem Elektronenakzeptor eine Freisetzung von Arsen aus Eisenoxid-Sorbaten. Im Zuge andauernder reduktiver Prozesse und mit dem Rückgang der Nitratkonzentration gewinnen Rücklösungsprozesse an Bedeutung. Seit der Jahrtausendwende zeigen sich reguläre zyklische Jahresverläufe der Arsenkonzentration mit Maxima im Spätsommer und Minima im Frühjahr. Eine Bilanzierung der Massenströme legt eine Quellfunktion der Gewässersedimente im Sommerhalbjahr offen, während der Rückgang der Arsenkonzentration im Winterhalbjahr hauptsächlich auf eine Auswaschung und, zu geringerem Anteil, auf eine interne Senkenfunktion zurückgeführt werden kann. Der Speicher Altenberg ist im Sommer thermisch geschichtet. Aber eine Schichtung von Arsen ist weit schwächer ausgeprägt. Ein Anstieg der Arsenkonzentration wurde sowohl im Hypo- als auch im Epilimnion nachgewiesen. Dies legt eine Arsenfreisetzung auch aus epilimnischen Sedimenten nahe, trotz oxischer Bedingungen im überstehenden Wasserkörper. Der dystrophen Natur des Gewässers entsprechend, wird die Triebkraft der zur Arsenfreisetzung führenden respirativen Prozesse dem Abbau humosen Kohlenstoffes zugeordnet. Für Sicker- und Interstitialwässer im System wurde die Mobilisation des Arsens in Zusammenhang mit der Respiration huminstoff-bürtigen Kohlenstoffes nachgewiesen. Neben der internen Arsenmobilisation ist auch die Arsennachlieferung aus dem Einzugsgebiet von Bedeutung. Die Arsenfracht befindet sich in diesen Wasserströmen vorzugsweise in Abhängigkeit von gelöstem organischen Kohlenstoff und der Abflussintensität. Daraus ergibt sich für den Arsenhaushalt des Speichersystems eine besondere Bedeutung von Starkregenereignissen mit verstärktem hypodermischen Abfluss und der Verfrachtung von Arsen in Assoziation mit wasserlöslichen Huminstoffen. Es wird eine Fallunterscheidung vorgestellt, wonach a) in trockenen Jahren mit geringen Durchflüssen sich Arsen aus der internen Rücklösung aus Sedimenten im Wasserkörper des Speichers anreichert; b) bei durchschnittlichen Durchflüssen im Speicher Verdünnungseffekte über die Anreicherung dominieren und tendenziell niedrige Arsenkonzentrationen resultieren; sowie c) in Jahren mit hohen dynamischen Durchflüssen bzw. ausgeprägten Starkregenereignissen ein verstärkter Eintrag aus dem Einzugsgebiet die Arsenkonzentrationen im Speicher ebenfalls ansteigen lässt. Eine exemplarische Analyse der chemischen Spezies des Elements hat ergeben, dass anorganisches fünfwertiges Arsen die dominante Form im Wasser des Speichers Altenberg ist. Der Anteil von höher toxischem dreiwertigen Arsen ist niedrig, ebenso auch der von methylierten Spezies. Daher wird auch eine Bildung volatiler Methylspezies, d.h. eine Öffnung des Arsenhaushaltes zur Atmosphäre, als unbedeutend eingeschätzt. Im Speichersystem offenbart sich eine spezifische Verknüpfung eines an Eisen-Huminstoff-Kolloide gebundenen Antransportes von Arsen aus dem Einzugsgebiet mit einer auf Huminstoffabbau basierenden, redoxchemisch gesteuerten saisonalen Arsenfreisetzung aus den Sedimenten. Dies hat Modellcharakter für Gewässersysteme, in denen hohe Huminstoffmobilität mit geogen oder auch anthropogen bedingten Arsenvorräten zusammentrifft. / Arsenic in drinking water and food represent regionally significant problems. The estimation of the dimension and a scientific explanation of the causes is a prerequisite for the protection of humans and nature. The Altenberg reservoir system was investigated as a drinking water facility, where elevated arsenic concentrations are observed. The aim of the investigations was to get findings about a possible continuation of recently observed trends of increasing arsenic concentrations in the water reservoir. For this purpose, the system was divided into compartments and these were investigated for running processes and dynamics. The system has a low productivity due to a low nutrient state, in particular a phosphate oligotrophy. Like a lot of surface waters in the northern hemisphere, it is shaped by high and increasing inputs of humic matter from the catchment area in context of declining immissions as well as of climate change. Additionally, there are internal and external sources of arsenic. At the bottom of the reservoirs, sediments rich in arsenic and humic matter were found. On the one hand side, they are the result of a long-lasting accumulation of sediments which originate in inputs from the catchment area, which is shaped by arsenic-rich basic rocks and histic soils. Likewise, an inundation of gleyic and histic soils with stored lithogenic respectively chalcogenic arsenic inside the construction ground of the reservoirs is an option. The importance of deposited fly ash for the system is assessed to be subordinate. For the Galgenteich, which is operated as a predam, since the beginning of arsenic measurements in 1997 an until the 2000 lasting steady increase in the concentration of arsenic concentration was found, which is significantly associated with a decrease in nitrate concentration. The nitrate concentration decrease in turn is part of an ecological regeneration of Central European forested catchments since the late eighties as a result of decreasing deposition loads. The most likely causal linkage between both parameters is a change in the redox-chemical environment of reservoir sediments. At past times of high depositions, high concentrations of nitrat as a secondary electron acceptor suppressed a release of arsenic from iron oxide sorbates. In the course of reductive processes, and with the decrease in nitrate concentration, release processes gain importance. Since the turn of the millennium regular cyclic annual courses of the arsenic concentration emerge with maxima in the late summer and minima in spring. An accounting of the mass flows reveals a source function of reservoir sediments in the summer season, whilst the decrease of the arsenic concentration during the winter months can be mainly attributed to washout and to a lesser proportion to an internal sink function. The Altenberg reservoir is thermally stratified in summer. But a stratification of arsenic is far less pronounced. An increase in the arsenic concentration was detected in hypolimnion and in epilimnion too. This suggests an arsenic release also from epilimnetic sediments despite oxic conditions in the overlaying water body. According to the dystrophic nature of the water body, the driving force leading to arsenic release during the respiratory processes is assigned to the use of humic carbon. For seepage and interstitial waters in the system, the mobilization of arsenic has been demonstrated in connection with the respiration of humic carbon. In addition to the internal arsenic mobilization, also a recent arsenic delivery from the catchment area is of importance. The arsenic load in these water flows preferably depends on contents of dissolved organic carbon and on runoff intensity. That implies a special meaning of heavy rainfall events with intensified hypodermic runoff and the transportation of arsenic in association with water-soluble humic matter for the arsenic budget of the reservoir system. A case distinction is presented, according to which a) in dry years with low flow rates sediment released arsenic accumulates in the reservoir water to higher concentrations; b) at average flow rates in dilution effects dominate over the enrichment with the result of low arsenic concentrations; and c) in years with high dynamic flows and strong heavy rains an increased input from the catchment area can also increase the arsenic concentration in the reservoir. An exemplary analysis of chemical species has shown that inorganic pentavalent arsenic is dominant in the water of the Altenberg reservoir. Higher toxic trivalent arsenic was found to a lesser extent as well as methylated species. Therefore, a formation volatile methyl species, i.e. an opening of the arsenic budget to atmosphere, is assessed to be insignificant. The dynamics in the reservoir system reveal a specific linkage between a catchment arsenic feed based on arsenic in iron-humic colloids and a redox-chemically controlled arsenic release from the sediments of the reservoir. This serves as a model for water systems, where high humic matter mobility coincides with geogenic or anthropogenic arsenic inventories.

The main aim of this thesis was to determine how marine metazoans might persist as ocean acidification (OA) conditions intensify. This was done using a combination of field surveys, field transplants and laboratory experiments with polychaetes from a site where volcanically-derived CO2 gas bubbles through the seafloor and drives the seawater pH down, resulting in a marine ecosystem representative of global OA projections for, or before, the year 2100. My first objective was to identify phenotypes, or traits, associated with OA tolerance (Chapter 2 and 5). To do this, I characterized the distribution of dominant calcifying polychaetes along natural pH gradients and used a comparative species recruitment trial to investigate life history traits underlying species’ OA tolerance, or vulnerability. I first found two dominant, closely related species of polychaete: Pileolaria militaris Claparède, 1870 and Simplaria sp. (Serpulidae, Spirorbinae). I then found that increased fecundity and rapid settlement are important traits in determining species’ abilities to persist in low pH environments (Chapter 2). Afterwhich, I investigated the life history traits of the non-calcifying polychaete, Platynereis dumerilii (Audouin & Milne Edwards, 1834), of one of the few species from the low pH site known to have broadcasting, pelagic development. I performed breeding experiments on P. dumerilii collected in both ambient and low pH sites and found that specimens from the low pH site were actually the direct developing brooder sister species, Platynereis massiliensis (Moquin-Tandon, 1869). By reanalayzing the distributions of both species at each site using genetic barcoding, I found clear evidence that direct development and brooding are dominant traits at low pH site, and for OA persistence (Chapter 5). My second objective was to use reciprocal transplant experiments to compare the relative importance of local adaptation and/or plasticity as potential mechanisms responsible for the differential tolerances of populations of the polychaete species Simplaria sp. to low pH. Laboratory transplants indicate that a local adaptation response occurred through genetic accommodation in the Simplaria sp. population from the low pH site. However, neither local adaptation nor plasticity appeared responsible for this species natural low pH persistence when assessed in situ (Chapter 3 & 4). My final objective was to create a framework using the polychaete vent model to identify other types of marine metazoans that are likely to be able to adapt to, and survive, under the predicted environmental conditions (Chapter 5). I overviewed the life history strategies of all dominant polychaetes in the low pH sites, and related trends in their life history strategies to those of other marine invertebrates. Brooding and direct development appear to be key traits for species likely to persist in future oceans pH. I conclude by summarizing how research regarding evolutionary responses may be advanced to add confidence to our projections of future marine metazoan responses.

Climate change is predicted to affect the larval stages of many marine organisms. Ocean warming can reduce larval survival and hasten larval development, whereas ocean acidification can delay larval development. Ocean acidification is especially concerning for marine organisms that develop and grow calcified shells or skeletons in an environment undersaturated with calcium carbonate minerals. This study assessed the effects of ocean warming and acidification on the fertilization and larval development of the green sea urchin, Lytechinus variegatus, a tropical species common in Florida and the Caribbean. After spawning, gametes were fertilized and embryos/larvae were reared at: 1) 28°C and pH 8.1 (control), 2) 28°C and pH 7.8 (ocean acidification scenario), 3) 31°C and pH 8.1 (ocean warming scenario), and 4) 31°C and pH 7.8 (ocean warming and acidification scenario). Exposure to acidified conditions had no effect on fertilization, but delayed larval development, stunted growth and increased asymmetry. Exposure to warm conditions decreased fertilization success at a high sperm to egg ratio (1,847:1), accelerated larval development, but had no significant effect on growth. Under exposure to both stressors (ocean warming and acidification), larval development was accelerated, but larvae were smaller and more asymmetric. These results indicate that climate change will have a serious impact on the larval development and growth of the green sea urchin, L. variegatus, and may negatively affect its persistence.

For decades, humans have impacted marine ecosystems in a variety of ways including contamination by pollution, fishing, and physical destruction of habitats. Global change has, and will, lead to alterations in in a number of abiotic factors of our ocean in particular reduced oxygen saturation, salinity changes, elevated temperature (ocean warming or OW) and elevated carbon dioxide (ocean acidification or OA). Now and in the future, OA and OW will operate together with local anthropogenic drivers such as oil pollution. And yet, at present, very little is known about their potential combined interactive effects on physiological performance and tolerance of marine organisms. Therefore, multiple driver experiments are required if we are to understand and predict future vulnerability of species, populations and ecosystems. Early life stages of invertebrates are generally considered most vulnerable to environmental stress. However, few studies consider the combined effects OA and OW on survival and growth during early development of marine invertebrates, and to our knowledge, there is no information on the additional effects of oil pollution. Therefore, the aim of this thesis was to investigate the effects of combined exposure to OA, OW, and incorporating local drivers such as oil pollution on the development, morphology and physiology of three economically and ecologically important marine invertebrates. These are Northern shrimp Pandalus borealis, Northern krill Meganyctiphanes norvegica, and the green sea urchin Strongylocentrotus droebachiensis. All are cold-water species, assumed to have a narrower tolerance than more temperate species, and so could be particular sensitive to combined stressor affects. Both Northern krill and to a lesser extent Northern shrimp larvae survived experimental conditions, mirroring those predicted under a future global change scenario (combined OA and OW exposure). Neither was hatching success affected. Both shrimp and krill larvae exhibited accelerated developmental rates and incurred greater maintenance costs as a result of exposure to these stressors. Shrimp larvae showed accelerated developmental rates (-9 days), increased metabolic rates (+20 %), and increased feeding rates (+20 %), but reduced growth (- 9 %) when exposed to OW compared with the control. OA increased development rate but only at the control temperature. Although juvenile mortality of krill was not affected by predicted OA/OW conditions, metabolic rate increased significantly (+ 36 %), as did larval developmental rate, while number of moults, feeding rate and growth (- 67 %) decreased significantly (- 67 %, - 60 % and -8 % respectively). Accelerated development was accompanied by greater maintenance costs possibly due to experience a mismatch between energy supply and demand. Both species had an excess of food, and so growth reduction was more likely to be associated with higher metabolic demands in the future global change treatments. Food shortage in situ, due to variable food availability in the sea and/or mismatch with key prey species (algae and zooplankton) could result in more negative effects on growth and ultimately survival. Green sea urchins were also able to survive OA exposure, without detectable effects on hatching success. However, at day 44 post-fertilization, larval body length in the OA treatment was 9 % lower compared to the control. Furthermore, there was a significant tendency of urchin larvae to increase swimming activity in the OA conditions that might indicate compensatory feeding. Elevated maintenance and repair costs as a result of exposure to multi-stressors affected the energy budget of all the three species studied here resulting in reduced growth. Global drivers (OA and OW) resulted in trade-offs with more energy reallocated to swimming activity and metabolism, rather than growth. Exposure to oil reduced the acquisition of energy by reduced feeding which in turn resulted in less energy being available for growth. Both shrimp and sea urchin larvae showed reduced activity and feeding when exposed to oil. It is possible that the reduced swimming activity observed may be due to a narcotic effect of the oil. Furthermore, early stage sea urchin larvae showed increased mortality when exposed to oil while the older larvae did not, indicating a stage specific toxicity to oil for sea urchin larvae. The combination of global drivers and oil pollution acted additively on growth for both sea urchin and shrimp larvae. The impact of combined drivers on the size of shrimp larvae was equal the sum of the negative impacts observed for each driver: a 5 % reduction when exposed to OA and OW, a 9 % reduction when exposed to oil, and a cumulative 15 % reduction when exposed to all stressors. Similarly, the impact of combined drivers on the size of sea urchin larvae was equal to the sum of the negative impacts observed for each driver: a 14 % reduction when exposed to OA, a 9 % reduction when exposed to oil, and a 21 % reduction when exposed to all drivers. Therefore, the study demonstrated the additive physiological effects of OA, OW and a contaminant, and indicated that larval (sea urchin and shrimp) resilience to future changes (i.e. pollution) could be greatly reduced if larvae were already energy limited and severely stressed (reduced development) as a result of exposure to the global drivers. This study therefore shows the importance that the effective management of local drivers such as oil pollution could have against the backdrop of OA and OW, and emphasises that it is important to study impacts of toxicants, such as an oil pollution, in the context of predicted changes in the environment, as OW and OA are becoming major concerns. Finally, the fact that some local and global drivers seem to act additively should encourage local managers to act on local driver regulations, to obtain positive effects on local populations and environment and thereby rendering them more resilient to the negative impacts of future global drivers.

This work describes efforts to improve methodologies and instrumentation for investigation of the marine CO2 system. In the first section of my thesis, a method was developed that provides simple, calibration-free measurements of seawater carbonate saturation states (Ωspec) based solely on the use of a laboratory spectrophotometer. Measurements of pH are made in paired optical cells, one with and one without added nitric acid. The amount of added nitric acid is determined through the direct proportionality between nitrate concentration and UV absorbance. After an initial calibration, the method is calibration-free and requires no volumetric or gravimetric analyses thereafter. Saturation state measurements can be obtained in twelve minutes and attain Global Ocean Acidification Observing Network accuracy goals over a wide range of conditions. This simple one-step measurement protocol is ideal for monitoring ocean acidification conditions in coastal areas, fish hatcheries and shellfish farms. The second section of my thesis outlines the development of a next-generation handheld photometer for field measurements of seawater pH. The hand-held instrument is simple to use, inexpensive, and has a pH measurement accuracy of ±0.01. Each photometer is calibrated by relating pH-indicator absorbance ratios (RB) obtained with the broadband photometer to indicator absorbance ratios (RN) obtained with a high quality, narrowband scanning spectrophotometer. The RB vs RN relationship for each photometer is entered into the instrument’s software, providing discrete, real-time pH observations from measurements of RB, salinity and temperature. Measurement accuracy is assessed through comparisons of photometer pH with pH observations obtained using standard measurement procedures and high-quality spectrophotometers. The targeted user-groups for these instruments include middle and high school students, citizen scientists, and resource managers

Ocean acidification is a phenomenon associated with global change and anthropogenic CO2 emissions that is changing the chemistry of seawater. These changes result in elevated pCO2 and reduced pH in seawater and this is impacting marine organisms in various ways. Marine fishes are considered generally tolerant to conditions of ocean acidification; however, these assumptions are based on juvenile and adult fish tolerance and the larval stages have not been frequently assessed. Furthermore, it has been suggested that temperate species, particularly those with an estuarine association, may be tolerant to variable CO2 and pH. This study used an eco-physiological approach to understand how the early life stages of Argyrosomus japonicus, an estuarine dependent marine fisheries species found in warm-temperate regions, may be impacted by ocean acidification. The metabolic response of early stage larvae (hatching to early juvenile stage) was assessed under conditions of elevated pCO2 and reduced pH in a controlled laboratory setting. Small volume static respirometry was used to determine the oxygen consumption rate of larvae raised in three pCO2 treatments including a low (pCO2 = 327.50 ± 80.07 µatm at pH 8.15), moderate (pCO2 477.40 ± 59.46 µatm at pH 8.03) and high treatment (PCO2 910.20 ± 136.45 µatm at pH 7.78). These treatment levels were relevant to the present (low) and projected conditions of ocean acidification for the years 2050 (moderate) and 2100 (high). Prior to experimentation with ocean acidification treatments, baseline metabolic rates and diurnal variation in oxygen consumption rates in early stage A. japonicus was determined. Distinct ontogenetic structuring of metabolic rates was observed in early stage A. japonicus, with no cyclical fluctuations in metabolic rate occurring during the 24 hour photoperiodic cycle. Pre-flexion larvae showed no metabolic response to ocean acidification treatments; however post-flexion stage larvae showed metabolic depression of standard metabolic rate in the moderate (32.5%) and high (9.5%) pCO2 treatments (P = 0.02). Larvae raised in the high pCO2 treatment also showed high levels of mortality with no individuals surviving past the post-flexion stage. Larvae raised in the moderate pCO2 treatment were unaffected. This study concluded that ocean acidification conditions expected for the end of the century will have significant impacts on the metabolism of early stage A. japonicus, which may result in reduced growth, retardation of skeletal development and ultimately survival as a result of increased mortality. Furthermore, the timing of reduced metabolic scope will significantly impact the recruitment ability of A. japonicus larvae into estuarine habitats. This could ultimately impact the sustainability of A. japonicus populations. Most importantly, this study highlighted the need to consider the combined effect of ontogeny and life-history strategy when assessing the vulnerability of species to ocean acidification.

Orientadores: Jose Luiz Antunes de Oliveira e Sousa, Paulo Dore Fernandes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-18T16:09:28Z (GMT). No. of bitstreams: 1 Neumann_LuisFernando_M.pdf: 28066529 bytes, checksum: 854d0f8d8feee96cc1c3e1adff5373dc (MD5) Previous issue date: 2011 / Resumo: O sucesso da estimulação por fraturamento hidráulico ou ácido é dependente da geração de condutividade. No fraturamento hidráulico sustentado, a condutividade é gerada pela introdução de uma quantidade significativa de um agente de sustentação granular e praticamente esférico. No fraturamento ácido, a condutividade é gerada por irregularidades reveladas devido à reação desigual do ácido em cada uma das faces da fratura naturalmente rugosa e da resistência destas mesmas irregularidades para suportar as tensões que atuam após o fechamento da fratura. A baixa resistência das irregularidades leva ao colapso e cicatrização da fratura ácida com a perda total da condutividade. Esta dissertação investiga a viabilidade da estimulação por fraturamento ácido em carbonatos microbiais rasos e profundos. Ensaios de laboratório em escala reduzida foram projetados para verificar se a condutividade de uma fratura induzida por reação química da rocha reservatório com um ácido forte pode ser mantida frente às elevadas tensões normais efetivas que agirão na fase de explotação do poço. A dissertação ainda investiga se o emprego de uma pequena quantidade de agente de sustentação é capaz de dividir os esforços aplicados sobre as irregularidades de uma fratura ácida e manter a condutividade por maiores períodos de tempo. As superfícies que imitam fraturas ácidas são criadas pelo ataque ácido em corpos de prova em condições de laboratório que reproduzem em escala aquelas observadas em um fraturamento ácido real. Imagens digitais são utilizadas para medir a rugosidade das fraturas ácidas e o consumo de rocha carbonática pelo ácido na face do corpo de prova. A resistência das irregularidades é medida indiretamente pelo decréscimo da condutividade da fratura ácida frente a tensões de confinamento crescentes. O efeito ou não da adição de agente de sustentação é medido pela comparação dos parâmetros da correlação empírica desenvolvida por Nierode e Kruk / Abstract: A well succeeded stimulation by hydraulic or acid fracturing is related to conductivity creation. In a hydraulic fracturing, the conductivity is created by means of introducing a significant amount of a propping agent. In an acid fracturing, the conductivity is related to the creation of asperities due to uneven acid reaction on each naturally rougher fracture side and the asperities strength to withstand high stresses that start to act just after fracture closure. Low asperities strength leads to collapse of acid fracture and fracture healing with total conductivity loss. The dissertation investigates the feasibility of acid fracturing stimulation in shallow and deep microbial carbonates. Laboratory tests were designed to verify if the acid fracture conductivity induced by chemical reaction of reservoir rock with a strong acid could be kept when facing the high effective normal stress that is expected in exploitation phase. The dissertation still investigates whether the use of a small amount of proppant is able to share the tension that acts on asperities and maintain the acid facture conductivity for longer periods. The surfaces that mimic acid fractures are created by acid etching specimens in laboratory conditions reduced in scale from those observed in an actual acid fracturing job. Digital images are used to measure fracture roughness and rock consumption by acid on the specimen face. The asperities strength is indirectly measured from acid conductivity decrease under increased confinement tension. The effect of adding or not adding propping agent is accomplished comparing empirical parameters from Nierode and Kruk correlation / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo

Orientador: Flavio Luis Schmidt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-14T15:45:20Z (GMT). No. of bitstreams: 1 Quast_Ernesto_M.pdf: 1820232 bytes, checksum: 30904cbd0aa1ec3f045d21ff606867b5 (MD5) Previous issue date: 2009 / Resumo: A garantia da segurança microbiológica de alimentos prontos para o consumo é essencial para a sua comercialização. Alimentos sensíveis ao calor, como o palmito, podem ser conservados com tratamentos térmicos brandos, adição de conservantes químicos, diminuição do pH ou por métodos combinados. Aliando-se a pasteurização com a acidificação adequada é possível impedir a germinação de Clostridium botulinum. A difusão de ácido até o interior do tecido vegetal deve ocorrer durante um intervalo de tempo que não seja suficiente para permitir a germinação de esporos, multiplicação das células e conseqüente formação de toxina botulínica. A cinética de acidificação dos diferentes tecidos que compõe o tolete de palmito foi estudada, observando-se uma diferença significativa do tempo necessário para o abaixamento do pH dos mesmos. O tempo para a acidificação de toletes de com diferentes comprimentos também foi avaliado, sendo observado o desenvolvimento de esporos de C. sporogenes (PA3679) em toletes de palmito pupunha com comprimento maior que 3 cm, com pH de equilíbrio de 4,41, indicando a possibilidade da formação de toxina botulínica em toletes com tamanho comercial em pH de equilíbrio = 4,5 desde que exista a presença de esporos de C. botulinum no seu interior. O palmito não é um meio rico para o desenvolvimento de esporos de PA3679, fato observado pela não germinação destes esporos em suspensão de palmito triturado e misturado, com pH < 5,2. Isto mostra que o pH no interior do tolete deve atingir pH < 5,2 para impedir o desenvolvimento de esporos microbianos / Abstract: Ready to eat food must have their food safety guaranteed. Heat sensible food, such as heart of palm, can be preserved using mild heat treatment, chemical preservatives addition and acidification or combined methods. Germination of Clostridium botulinum can be inhibited by combining mild heat treatment and lowering of pH. The diffusion of the acid to the interior of the vegetable tissue must be fast enough not to permit spores germination, multiplication of the vegetative cells and consequent botulinum toxin formation. Study of the acidification of heart of palm showed a significant difference between the tissues regarding to the time necessary for lowering the pH. Hearts of palm Bactris gasipaes were evaluated and were observed the growth of C. sporogenes (PA3679) spores in stems with length larger than 3 cm in equilibrium pH of 4.41, indicating the possibility of botulism toxin formation in commercial heart of palm preserves with pH = 4.5 if spores of C. botulinum are present in the vegetable tissue. Heart of palm is not rich growing medium as observed that spores of PA3679 did not grow in suspension of triturated heart or palm with pH < 5.2. This fact shows that pH in the interior of heart of palm should reach pH < 5.2 to inhibit bacteria spores development / Mestrado / Mestre em Tecnologia de Alimentos