Download or read book Effects of Ocean Acidification on Early Developmental Stages of the Pacific Oyster Crassostrea Gigas in an Aquaculture Setting written by Manon Picard and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Ocean Acidification on Multiple Life History Stages of the Pacific Oyster Crassostrea Gigas written by Emma B. Timmins-Schiffman and published by . This book was released on 2014 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: As global climate change accelerates, due in large part to increasing emissions of carbon dioxide and other greenhouse gases from fossil fuel use, agriculture, and large-scale changes in land use, natural ecosystems bear the consequences. For marine systems these include increased mean seawater temperature, changes in carbonate chemistry equilibria, and increased pollutant loading due to non-point run-off, among other effects. Human-induced environmental changes will not have the same magnitude of effect in all regions, but on average the changes occurring are rapid and significant. Natural populations will either need to acclimatize and/or adapt, or shift their ranges to enable continued existence. This dissertation explores the effects of ocean acidification on the Pacific oyster, Crassostrea gigas. Oysters are sedentary and inhabit a naturally variable environment (the intertidal zone) and thus may be pre-adapted to withstand rapid environmental change. Oysters and similarly sedentary organisms are ideal for investigating the effects of environmental change on biology because they are not able to escape these changes, but must respond physiologically (acclimatize) if they are to survive. Due to this ecological history, oysters provide a model that allows us to explore potential physiological mechanisms that are needed in a response to specific environmental changes as well as the limits of these mechanisms. In the first chapter, the effects of elevated partial pressure of CO2 (pCO2, a major driver of ocean acidification) on oyster larvae are explored. Larvae were exposed to low pH during early development, a period that included the transition from energetic dependence on maternally derived lipids to dependence on exogenous resources. Larvae were found to experience a developmental delay at elevated pCO2, manifested as smaller size and slower rate of shell deposition. These significant effects of ocean acidification on early larval development may indicate a bottleneck in the oyster life cycle as the pH of marine waters decreases. Subsequent research has shown that these effects at early larval stages can carry over into later stages after settlement in another oyster species (Hettinger et al. 2012). In order to better understand the effects of environmental change on oyster physiology, we developed proteomic tools to explore changes in protein pathways in oyster gill (ctenidia) tissue. The second chapter explores the gill proteome (suite of expressed proteins) of adult oysters. Characterization of the proteome provides insight into the physiological mechanisms that may be available to the oyster during response to an environmental stress. The results revealed that the ctenidia proteome includes a diverse array of proteins that accomplish many functions and that it is a metabolically active tissue. The proteome sequencing lays the groundwork for exploring how ocean acidification affects various proteomic pathways in the tissue that acts as the interface between the oyster and its environment. Lastly, the adult oyster response to ocean acidification and a second stress are explored via proteomics, fatty acid profiles, glycogen content, shell microstructure, and mortality in response to heat shock. There was a significant impact of ocean acidification on oyster shell integrity, but no effects after one month of exposure on relative amounts of fatty acid, glycogen or response to acute heat shock. Through the proteomic analysis, we revealed an active and significant proteomic response to ocean acidification exposure, uncovering some of the mechanisms behind the observed macro-phenotypic changes. Additionally, the proteomic response to mechanical stimulation was largely altered between low and high pCO2, suggesting that ocean acidification can fundamentally change how oysters respond to a second stress.

Download or read book Ocean Acidification Influences on Physiology and Epigenetics in the Pacific Oyster Crassostrea Gigas written by Yaamini Ranjani Venkataraman and published by . This book was released on 2021 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: As ocean acidification continues to impact marine ecosystems at unprecedented rates, phenotypicplasticity may allow organisms to withstand more stressful conditions. Genomic methods can elucidate molecular mechanisms that contribute to phenotypic plasticity, allowing for a deeper understanding of how physiological processes will be impacted by low pH. My dissertation examines the effects of ocean acidification on the Pacific oyster (Crassostrea gigas) stress response and reproduction; elucidate how exposure history impacts phenotype; and explore the role of functional role DNA methylation in somatic and reproductive tissue. I investigated the effect of regional environmental variation on the molecular physiology of C. gigas outplanted at five different estuarine sites (four in Puget Sound, one in Willapa Bay) in Washington, USA using gel-free proteomic methods. While there was no difference in survival, or any protein abundances due to pH differences between sites, C. gigas outplanted at the site with the highest temperature had significantly higher abundances of antioxidant enzymes and molecular chaperones, elucidating the molecular underpinnings of thermotolerance. In a hatchery setting, I explored the impact of ocean acidification on reproductive maturity and output. A seven week low pH exposure did not affect sex ratio or maturation stage; however, it did significantly affect survival of larvae. Even though adult oysters spent four months in ambient pH conditions between low pH exposure and strip spawning, larvae from females that experienced low pH conditions had significantly higher mortality. Finally, I conducted the first investigations examining the effect of ocean acidification in C. gigas methylomes. To investigate the role of environmentally-responsive methylation in reproductive tissue, I analyzed gonad methylomes of female C. gigas exposed to low pH. A total of 1,599 differentially methylated loci (DML) were found in gene bodies. The genic DML were associated with cilium movement, development, and cytoskeletal processes, implying a need to regulate cellular growth in the gonad in response to low pH. I then explored the influence of low pH on the somatic tissue methylome using diploid and triploid oyster ctenidia. Differences in ploidy status yielded 154 DML. These ploidy-DML were associated with cell-cell adhesion and dephosphorlylation processes, which are not commonly associated with methylome changes in organisms that undergo natural polyploidization. The 178 pH-DML were associated with processes commonly observed in oysters exposed to ocean acidification, including apoptosis, protein ubiquitination, zinc ion binding, and cytoskeletal processes. In both reproductive and somatic tissue, the enrichment of DML in genes with multiple transcripts could indicate a role for methylation to regulate gene expression via alternative splicing. Investigating the molecular underpinnings of responses to ocean acidification in C. gigas will provide a thorough understanding of this global aquaculture product’s ability to withstand future ocean conditions.

Download or read book Climate Change written by Laura M. Parker and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout the Earth's history climate change has led to a proliferation and disappearance of species thus playing a major role in shaping the structure of marine ecosystems. Over the next century, rising atmospheric carbon dioxide (CO2) levels will cause a rise in the partial pressure of CO2 (pCO2) in the surface ocean leading to a reduction in surface ocean pH from 8.1 to 7.7 units and a reduction in the concentration of surface ocean carbonate ions (in a process known as 'ocean acidification') vital in the construction of calcium carbonate (CaCO3) shells and skeletons. At the same time, this rise in atmospheric CO2 levels will lead to an increase in sea-surface temperatures (SSTs). Of growing concern are the potentially serious implications that ocean acidification and rising SSTs may have on marine organisms and ecosystems and the potential risk to marine aquaculture internationally. Recent studies, which have mimicked ocean acidification, have reported adverse consequences of elevated pCO2, including reduced calcification and growth, and increased rates of abnormality and mortality in larvae and adults of a range of marine organisms. Yet, we know comparatively little of the synergistic consequences of elevated pCO2 and temperature nor the potential for species to acclimate through genetic adaptation, at the population and ecosystem level. This lack of knowledge limits our ability to create models that accurately predict the consequences of future climate change. Among the organisms most likely to be affected in an acidifying and warming ocean are marine calcifying organisms which construct shells and skeletons of CaCO3. Studies on these organisms, to date, have focused predominately on adults, with comparatively few considering the sensitive early life history stages. This study compared the synergistic effects of elevated pCO2 and temperature on the early life history stages of two ecologically and economically important oysters: the Sydney rock oyster, Saccostrea glomerata and the Pacific oyster, Crassostrea gigas. Gametes, embryos, larvae and spat were exposed to four pCO2 (375, 600, 750, 1000 ppm) and four temperature (18, 22, 26, 30 °C) levels in acute exposure experiments. At elevated pCO2 and suboptimal temperatures there was a reduction in the fertilisation success of gametes, a reduction in the development of embryos and size of larvae and spat and an increase in abnormal morphology of larvae. These effects varied between species with S. glomerata having greater sensitivity than C. gigas. Combined, elevations in pCO2 of 750-1000 ppm and a temperature of 30 °C resulted in 100% mortality of D-veliger larvae of S. glomerata. In contrast, the same pCO2 and temperature combination resulted in only 26% mortality of D-veliger larvae of C. gigas. A comparison between two commonly used methods for manipulating the seawater carbonate system (HCl-acidification and CO2-acidification) showed that there was no significant difference in the responses of S. glomerata and C. gigas to the two methods. This indicates that both HCl-acidification and CO2-acidification are adequate methods for determining the effects of elevated pCO2 for these species.

Download or read book Ocean Acidification written by National Research Council and published by National Academies Press. This book was released on 2010-09-14 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.

Download or read book Ocean Acidification Affects Larval Swimming in Ostrea Lurida But Not Crassostrea Gigas written by Shannon Buckham and published by . This book was released on 2015 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impacts of Ocean Acidification and Mitigative Hydrated Lime Addition on Pacific Oyster Larvae written by Carolyn Susanne Duckham and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic CO2 emissions are rapidly altering marine chemistry, significantly impacting calcifying organisms' ability to produce and maintain shells. In the Pacific Northwest, shellfish hatcheries have already observed mass die offs of larvae, potentially from ocean acidification. This study aims to elucidate if hydrated lime can be used at the hatchery level to chemically reverse ocean acidification and its negative impacts on larval stages of the Pacific oyster, Crassostrea gigas. For 24 days, larvae were exposed to four treatments: ambient - 390 ppm, ocean acidified - 1500 ppm, limed-ambient and limed-ocean acidified treatments to meet pre-industrial levels ~280 ppm. Hydrated lime significantly increased larval shell length after two weeks of development, but did not affect survival or percent abnormality between treatments. Investigations into mitigative lime use appear cost effective and feasible for shellfish hatcheries under future CO2 scenarios, but requires more extensive research at the hatchery level, and for other species.

Download or read book Biomineralization Mechanism of the Pearl Oyster Pinctada fucata written by Rongqing Zhang and published by Springer. This book was released on 2019-01-04 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an overview of our current understanding of the biomineralization mechanisms for shell formation in the pearl oyster Pinctada fucata, based on molecular biology, biochemistry, cell biology, structural biology and environmental biology. Pinctada fucata is the major pearl-producing shellfish in the South China Sea and is also an established model system for the research on the nacre biomineralization mechanism. Extensive studies on nacre biomineralization have provided valuable information for novel bionic material design. Discussing the isolation and gene cloning of the matrix proteins involved in the shell formation, as well as the cell signaling pathways, shell microstructures, and the environmental impacts on shell biomineralization, it is a valuable reference resource for researchers working in the field of nacre biomineralization and biomaterials.

Download or read book Evaluation of the Deleterious Effects of Heavy Metals and Pesticides on Early Life Stages and Gametes of the Pacific Oyster Crassostrea Gigas written by Huong Mai and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The coastal areas are subject to multiple anthropogenic pressures including chemical pollution that can pose a real risk to the sustainability of aquatic species. The Arcachon Bay, macrotidal lagoon located on the French Atlantic coast, is the important ecosystem for oyster farming. But for several years, the oyster farms face lower recruitment and high mortality of oyster spat. Chemical contamination of the environment as a factor that may contribute to the observed effects on oysters has so far not been investigated.The present thesis aimed at evaluating through different approaches, of the potential toxicity of heavy metals and pesticides representative of the Arcachon Bay contamination on the early life stages of the Pacific oyster, Crassostrea gigas. Embryotoxicity, genotoxicity and expression levels of eleven targeted genes were studied. Firstly, different pesticides (S-metolachlor, irgarol, and diuron) and metals (copper and cadmium) were separately tested to determine their spectrum of effects. It were shown that exposure of gametes and embryos of oyster to environmental concentrations of pesticides and copper increased developmental abnormalities and DNA damage, and reduced fertilization success and affected offpring quality. Cadmium, meanwhile, showed no embryotoxic and genotoxic effects at the concentrations found in the Arcachon Bay. Metabolites of metolachlor, metolachlor ESA and metolachlor OA, are found in the Arcachon Bay at higher concentrations than their parent compound. The results showed that these metabolites were less embryotoxic and genotoxic on oyster embryos and spermatozoa than metolachor. Significant changes in expression of genes involved in antioxidant defense were observed for oyster larvae exposed to metolachlor and metolachlor ESA. Toxicity of mixtures of pesticides representative of the Arcachon Bay contamination with and without copper was then evaluated. Exposures of oyster embryos to these mixtures lead to development defects, DNA damage and changes in the expression of genes involved mainly in oxidative stress responses. Finally, mapping of toxicity of sediments from the Arcachon Bay was conducted for four seasons of 2011 with the oyster embryo-larvae assay. Sediments collected from Arguin exhibited low toxicity, regardless any season. In contrast, sediments from Le Tès showed higher toxicity in spring and summer seasons compared to winter season.From this work, it can be hypothesized that chemical contamination of the Arcachon Bay represents a threat for oyster reproduction and development.

Download or read book Summer Mortality of Pacific Oyster Crassostrea Gigas written by Jean-François Samain and published by Editions Quae. This book was released on 2008-02-13 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass oyster mortalities have been known for many years throughout the world, but no strictly pathological explication has been found. This book describes how environmental influences, reproduction, stress, genetics, pathogens and temperature contribute to oyster summer mortality in France. An interaction model is derived from the results and recommendations are made for forecasting and managing risk factors.

Download or read book Proteomic Analysis of Oyster Larvae Reveals Molecular Mechanism of Ocean Acidification and Multiple Stressor Effects written by Dineshram Ramadoss and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Proteomic Analysis of Oyster Larvae Reveals Molecular Mechanism of Ocean Acidification and Multiple Stressor Effects" by Dineshram, Ramadoss, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The increase in carbon dioxide emissions due to human activities has led to drastic variations in global climate. In addition to global warming and extreme weather patterns, the high CO2 levels have been leading to progressive ocean acidification. Compounded with other climate change related stressors, ocean acidification will hinder the ability of marine organisms to adapt to the ensuing changes and might affect human dependence on oceans as a source of food. Most marine organisms have complex life cycles, involving metamorphosis from larval to adult forms. In the early stages of life, oysters have calcium carbonate shells that are particularly sensitive to low pH, and the rapid climatic changes can compromise their metamorphosis. High temperature, low salinity and low pH resulting from ocean acidification are detrimental to both native and cultivated oyster populations. Although mechanistic studies to understand the tolerance responses of closely related species would be significant in this context, none have been reported to date. Therefore, this thesis aims to reveal the mechanisms that distinguish the "winners" from the "losers" among the selected aquatic species of commercial importance, in withstanding the stress induced by climate change. The present study employed molecular approaches to evaluate the interactive and cumulative effects of multiple stressors on large-scale cultures of pediveliger larvae from two oyster populations, Crassostrea hongkongensis and Crassostrea gigas. The study undertook transcriptomic and proteomic profiling of changes induced by ocean acidification in the larvae. The results revealed that oyster larvae could adopt an energy 'trade-off' strategy through metabolic suppression and adjust cell signalling pathways to overcome the stress induced by ocean acidification. Information from the oyster genome database facilitated the shotgun proteomics investigations on oyster larvae remarkably revealed over 1350 proteins in both the species. The study identified species- and stressor-specific tolerance responses, and survival mechanisms that preserved calcification, in oyster larvae. The larvae showed depletion of energy reserves due to enhanced metabolism, oxidative damage-induced immune response and metabolic suppression. The study reveals the existence of tolerance mechanisms in oysters that help them adapt to stresses resulting from climate change. It pioneered the use of a proteomics approach to understand the impact of multiple stressors on oyster larvae and the molecular mechanisms underlying their successful adaptation to them. Highlighted several potential possible biomarkers in this study will likely to play an important role in identifying oyster species showing heritable tolerance for future aquaculture. DOI: 10.5353/th_b5317012 Subjects: Ocean acidification Oysters - Effect of stress on

Download or read book The Eastern Oyster written by Victor S. Kennedy and published by University of Maryland Sea Grant Publications. This book was released on 1996 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1966 Congress passed the National Sea Grant College Program Act to promote marine research, education, and extension services in institutions along the nation's ocean and Great Lakes coasts. In Maryland a Sea Grant Program -- a partnership among federal and state governments, universities, and industries -- began in 1977, and in 1982 the University of Maryland was named the nation's seventeenth Sea Grant College. The Maryland Sea Grant College focuses its efforts on the Chesapeake Bay, with emphasis on the marine concerns of fisheries, seafood technology, and environmental quality. The first comprehensive review of the biology of the eastern oyster in more than thirty years. The twenty-one chapters synthesize every aspect of oyster biology -- for instance, general anatomy, physiology, the circulatory system, reproduction, genetics, diseases -- and issues related to management and aquaculture.

Download or read book Measured Effects of the Pacific Oyster Crassostrea Gigas on Water Quality for the Design of a Holding System written by Marcin Whitman and published by . This book was released on 1989 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Species Profiles written by Gilbert B. Pauley and published by . This book was released on 1988 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biochemical Changes in the Pacific Oyster Crassostrea Gigas Thunberg 1795 During Larval Development and Metamorphosis written by Bruce Robert Bartlett and published by . This book was released on 1978 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy strategies of early development of the Pacific Oyster, Crassostrea gigas, were examined. Changes in proteins, total carbohydrates, free reducing sugars and total and neutral lipids were determined for the unfertilized egg and larval stages through 13 days post-settlement. During early larval stages neutral lipid levels decreased and provided the principle source of energy for development. Subsequently they remained unchanged throughout settlement and metamorphosis. Protein levels increased during larval stages and remained largely unchanged after settlement. Total carbohydrate levels were unchanged during larval development and through settlement and metamorphosis. Phospholipid values rose slightly during early larval stages and remained unchanged through settlement and metamorphosis. Starvation experiments confirmed the aforementioned findings that neutral lipid was an important source of energy during early larval life. Protein, however, contributed more energy than neutral lipid in late larval life. This study has shown that in C. gigas development, contrary to the European oyster Ostrea edulis, neutral lipid was not accumulated during larval feeding nor utilized during settlement and metamorphosis relative to other organic fractions.

Download or read book Species Profiles written by Gilbert B. Pauley and published by . This book was released on 1988 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Ocean Acidification on Gonadal Development of the Eastern Oyster Crassostrea Virginica written by Ashley DeMay and published by . This book was released on 2016 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: