Готові списки джерел за темами / Marine organisms sensitivity

Добірка наукової літератури з теми "Marine organisms sensitivity"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Статті в журналах з теми "Marine organisms sensitivity"

de Hoop, Lisette, Aafke M. Schipper, Rob S. E. W. Leuven, Mark A. J. Huijbregts, Gro H. Olsen, Mathijs G. D. Smit, and A. Jan Hendriks. "Sensitivity of Polar and Temperate Marine Organisms to Oil Components." Environmental Science & Technology 45, no. 20 (October 15, 2011): 9017–23. http://dx.doi.org/10.1021/es202296a.

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Putman, Nathan F., and Ruoying He. "Tracking the long-distance dispersal of marine organisms: sensitivity to ocean model resolution." Journal of The Royal Society Interface 10, no. 81 (April 6, 2013): 20120979. http://dx.doi.org/10.1098/rsif.2012.0979.

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Ocean circulation models are widely used to simulate organism transport in the open sea, where challenges of directly tracking organisms across vast spatial and temporal scales are daunting. Many recent studies tout the use of ‘high-resolution’ models, which are forced with atmospheric data on the scale of several hours and integrated with a time step of several minutes or seconds. However, in many cases, the model's outputs that are used to simulate organism movement have been averaged to considerably coarser resolutions (e.g. monthly mean velocity fields). To examine the sensitivity of tracking results to ocean circulation model output resolution, we took the native model output of one of the most sophisticated ocean circulation models available, the Global Hybrid Coordinate Ocean Model, and averaged it to commonly implemented spatial and temporal resolutions in studies of basin-scale dispersal. Comparisons between simulated particle trajectories and in situ near-surface drifter trajectories indicated that ‘over averaging’ model output yields predictions inconsistent with observations. Further analyses focused on the dispersal of juvenile sea turtles indicate that very different inferences regarding the pelagic ecology of these animals are obtained depending on the resolution of model output. We conclude that physical processes occurring at the scale of days and tens of kilometres should be preserved in ocean circulation model output to realistically depict the movement marine organisms and the resulting ecological and evolutionary processes.

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MacLeod, Colin D., and Robert Poulin. "Parasitic infection: a buffer against ocean acidification?" Biology Letters 12, no. 5 (May 2016): 20160007. http://dx.doi.org/10.1098/rsbl.2016.0007.

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Recently, there has been a concerted research effort by marine scientists to quantify the sensitivity of marine organisms to ocean acidification (OA). Empirical data generated by this research have been used to predict changes to marine ecosystem health, biodiversity and productivity that will be caused by continued acidification. These studies have also found that the effects of OA on marine organisms can be significantly modified by additional abiotic stressors (e.g. temperature or oxygen) and biotic interactions (e.g. competition or predation). To date, however, the effects of parasitic infection on the sensitivity of marine organisms to OA have been largely ignored. We show that parasitic infection significantly altered the response of a marine gastropod to simulated OA conditions by reducing the mortality of infected individuals relative to uninfected conspecifics. Without the inclusion of infection data, our analysis would not have detected the significant effect of pH on host mortality. These results strongly suggest that parasitic infection may be an important confounding factor in OA research and must be taken into consideration when assessing the response of marine species to OA.

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Bennett, Scott, Carlos M. Duarte, Núria Marbà, and Thomas Wernberg. "Integrating within-species variation in thermal physiology into climate change ecology." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1778 (June 17, 2019): 20180550. http://dx.doi.org/10.1098/rstb.2018.0550.

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Accurately forecasting the response of global biota to warming is a fundamental challenge for ecology in the Anthropocene. Within-species variation in thermal sensitivity, caused by phenotypic plasticity and local adaptation of thermal limits, is often overlooked in assessments of species responses to warming. Despite this, implicit assumptions of thermal niche conservatism or adaptation and plasticity at the species level permeate the literature with potentially important implications for predictions of warming impacts at the population level. Here we review how these attributes interact with the spatial and temporal context of ocean warming to influence the vulnerability of marine organisms. We identify a broad spectrum of thermal sensitivities among marine organisms, particularly in central and cool-edge populations of species distributions. These are characterized by generally low sensitivity in organisms with conserved thermal niches, to high sensitivity for organisms with locally adapted thermal niches. Important differences in thermal sensitivity among marine taxa suggest that warming could adversely affect benthic primary producers sooner than less vulnerable higher trophic groups. Embracing the spatial, temporal and biological context of within-species variation in thermal physiology helps explain observed impacts of ocean warming and can improve forecasts of climate change vulnerability in marine systems. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.

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DeForest, David K., and Christian E. Schlekat. "Species sensitivity distribution evaluation for chronic nickel toxicity to marine organisms." Integrated Environmental Assessment and Management 9, no. 4 (May 28, 2013): 580–89. http://dx.doi.org/10.1002/ieam.1419.

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Araújo-Castro, Cristiane M. V., Lília P. Souza-Santos, Anny Gabrielle A. G. Torreiro, and Karina S. Garcia. "Sensitivity of the marine benthic copepod Tisbe biminiensis (copepoda, harpacticoida) to potassium dichromate and sediment particle size." Brazilian Journal of Oceanography 57, no. 1 (March 2009): 33–41. http://dx.doi.org/10.1590/s1679-87592009000100004.

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For the future use of the marine benthic copepod Tisbe biminiensis in solid-phase sediment toxicological bioassays, the present study investigated the effect of muddy sediment from the Maracaípe estuary (northeastern Brazil), sediment particle size and the reference toxicant potassium dichromate on the species. Muddy sediment from Maracaípe can be used as control sediment, since it does not interfere in the copepod life-cycle and has metal contamination levels that are unlikely to produce any detrimental biological effects on benthic invertebrates. Neither survival nor fecundity was affected by grain size, suggesting that this species can be used with any kind of sediment from muddy to sandy. The sensitivity of T. biminiensis to K2Cr2O7 in acute tests was similar to that of other organisms. The LC50 (lethal concentration to 50% of the test organisms) medium values for T. biminiensis were 7.51, 4.68 and 3.19 mg L-1 for Cr in 48, 72 and 96 h, respectively. These results suggest that T. biminiensis is a promising organism for use in solid-phase sediment toxicity assessments.

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McCormick, Lillian R., and Lisa A. Levin. "Physiological and ecological implications of ocean deoxygenation for vision in marine organisms." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2102 (August 7, 2017): 20160322. http://dx.doi.org/10.1098/rsta.2016.0322.

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Climate change has induced ocean deoxygenation and exacerbated eutrophication-driven hypoxia in recent decades, affecting the physiology, behaviour and ecology of marine organisms. The high oxygen demand of visual tissues and the known inhibitory effects of hypoxia on human vision raise the questions if and how ocean deoxygenation alters vision in marine organisms. This is particularly important given the rapid loss of oxygen and strong vertical gradients in oxygen concentration in many areas of the ocean. This review evaluates the potential effects of low oxygen (hypoxia) on visual function in marine animals and their implications for marine biota under current and future ocean deoxygenation based on evidence from terrestrial and a few marine organisms. Evolutionary history shows radiation of eye designs during a period of increasing ocean oxygenation. Physiological effects of hypoxia on photoreceptor function and light sensitivity, in combination with morphological changes that may occur throughout ontogeny, have the potential to alter visual behaviour and, subsequently, the ecology of marine organisms, particularly for fish, cephalopods and arthropods with ‘fast’ vision. Visual responses to hypoxia, including greater light requirements, offer an alternative hypothesis for observed habitat compression and shoaling vertical distributions in visual marine species subject to ocean deoxygenation, which merits further investigation. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’.

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Canova, Luca, Michela Sturini, Federica Maraschi, Stefano Sangiorgi, and Elida Nora Ferri. "A Comparative Test on the Sensitivity of Freshwater and Marine Microalgae to Benzo-Sulfonamides, -Thiazoles and -Triazoles." Applied Sciences 11, no. 17 (August 25, 2021): 7800. http://dx.doi.org/10.3390/app11177800.

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The evaluation of the ecotoxicological effects of water pollutants is performed by using different aquatic organisms. The effects of seven compounds belonging to a class of widespread contaminants, the benzo-fused nitrogen heterocycles, on a group of simple organisms employed in reference ISO tests on water quality (unicellular algae and luminescent bacteria) have been assessed to ascertain their suitability in revealing different contamination levels in the water, wastewater, and sediments samples. Representative compounds of benzotriazoles, benzothiazoles, and benzenesulfonamides, were tested at a concentration ranging from 0.01 to 100 mg L−1. In particular, our work was focused on the long-term effects, for which little information is up to now available. Species-specific sensitivity for any whole family of pollutants was not observed. On average, the strongest growth rate inhibition values were expressed by the freshwater Raphidocelis subcapitata and the marine Phaeodactylum tricornutum algae. R. subcapitata was the only organism for which growth was affected by most of the compounds at the lowest concentrations. The tests on the bioluminescent bacterium Vibrio fisheri gave completely different results, further underlining the need for an appropriate selection of the best biosensors to be employed in biotoxicological studies.

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Deidda, Irene, Roberta Russo, Rosa Bonaventura, Caterina Costa, Francesca Zito, and Nadia Lampiasi. "Neurotoxicity in Marine Invertebrates: An Update." Biology 10, no. 2 (February 18, 2021): 161. http://dx.doi.org/10.3390/biology10020161.

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Invertebrates represent about 95% of existing species, and most of them belong to aquatic ecosystems. Marine invertebrates are found at intermediate levels of the food chain and, therefore, they play a central role in the biodiversity of ecosystems. Furthermore, these organisms have a short life cycle, easy laboratory manipulation, and high sensitivity to marine pollution and, therefore, they are considered to be optimal bioindicators for assessing detrimental chemical agents that are related to the marine environment and with potential toxicity to human health, including neurotoxicity. In general, albeit simple, the nervous system of marine invertebrates is composed of neuronal and glial cells, and it exhibits biochemical and functional similarities with the vertebrate nervous system, including humans. In recent decades, new genetic and transcriptomic technologies have made the identification of many neural genes and transcription factors homologous to those in humans possible. Neuroinflammation, oxidative stress, and altered levels of neurotransmitters are some of the aspects of neurotoxic effects that can also occur in marine invertebrate organisms. The purpose of this review is to provide an overview of major marine pollutants, such as heavy metals, pesticides, and micro and nano-plastics, with a focus on their neurotoxic effects in marine invertebrate organisms. This review could be a stimulus to bio-research towards the use of invertebrate model systems other than traditional, ethically questionable, time-consuming, and highly expensive mammalian models.

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Barry, John F., Matthew J. Turner, Jennifer M. Schloss, David R. Glenn, Yuyu Song, Mikhail D. Lukin, Hongkun Park, and Ronald L. Walsworth. "Optical magnetic detection of single-neuron action potentials using quantum defects in diamond." Proceedings of the National Academy of Sciences 113, no. 49 (November 22, 2016): 14133–38. http://dx.doi.org/10.1073/pnas.1601513113.

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Magnetic fields from neuronal action potentials (APs) pass largely unperturbed through biological tissue, allowing magnetic measurements of AP dynamics to be performed extracellularly or even outside intact organisms. To date, however, magnetic techniques for sensing neuronal activity have either operated at the macroscale with coarse spatial and/or temporal resolution—e.g., magnetic resonance imaging methods and magnetoencephalography—or been restricted to biophysics studies of excised neurons probed with cryogenic or bulky detectors that do not provide single-neuron spatial resolution and are not scalable to functional networks or intact organisms. Here, we show that AP magnetic sensing can be realized with both single-neuron sensitivity and intact organism applicability using optically probed nitrogen-vacancy (NV) quantum defects in diamond, operated under ambient conditions and with the NV diamond sensor in close proximity (∼10 µm) to the biological sample. We demonstrate this method for excised single neurons from marine worm and squid, and then exterior to intact, optically opaque marine worms for extended periods and with no observed adverse effect on the animal. NV diamond magnetometry is noninvasive and label-free and does not cause photodamage. The method provides precise measurement of AP waveforms from individual neurons, as well as magnetic field correlates of the AP conduction velocity, and directly determines the AP propagation direction through the inherent sensitivity of NVs to the associated AP magnetic field vector.

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Більше джерел

Дисертації з теми "Marine organisms sensitivity"

Rodriguez, Dominguez Almendra. "How marine organisms cope with changing climate." Thesis, 2020. http://hdl.handle.net/2440/126088.

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As anthropogenic CO2 levels continue to rise, the oceans are becoming warmer and more acidic. Organisms need to adjust to such environmental changes and display a variety of mechanisms to maintain their fitness in novel conditions. These adjustments can operate at various levels of biological organisation: from cellular levels to organismal physiology and behaviour. Such adaptive responses of species will determine their persistence under future ocean warming and acidification conditions. If organisms are capable of maintaining fitness after long-term exposure to a stressor this can be indicative of acclimation potential. However, their sensitivity to stressors is linked to life stage. Early life phases are considered to be the most vulnerable to fluctuations in the environment. If detrimental effects occur during an organism’s early life this could modify its capability to handle stress at later life stages. The physiological and behavioural adjustments that are triggered in response to changing conditions can lead to modifications in the phenotypic distributions of traits within a population. Analysing the variation of phenotypical traits offers an insight into the capacity of populations to persist by acclimating to their environment. In this thesis I evaluated the sensitivity of marine organisms to ocean warming and acidification and their various coping mechanisms. I reveal that ocean acidification and warming can alter the behaviour of fish species by increasing their anxiety (chapter 2), boldness (chapter 3 and 5), or feeding rates (chapter 2). Modifications in feeding behaviour were linked to physiological and to changing environmental conditions, creating a feedback mechanism between their cellular and behavioural responses that helped organisms maintain their fitness (chapter 3). However, altered behaviours in a population are not always accompanied by physiological changes, as in chapter 5 I also found changes in risk taking behaviours that did not alter the body condition of temperate or tropical fishes. The direction of responses (negative, positive or neutral) exhibited by a species in response to changing conditions will depend on their specific physiological requirements that determine their sensitivity to stressors. Using a meta-analysis in chapter 4 I showed that when facing climatic stressors, the growth and survival of diverse marine species vary according to their species-specific physiological requirements. For example, negative responses in growth were observed in calcifying organisms and positive responses were found for primary producers. Life stage was key in determining survival, as eggs and larvae showed to be more vulnerable to stressors than older juvenile and adult stages. The sensitivity of early life stages was also found in laboratory experiments performed in this thesis (chapter 2). A mouthbrooder species was used to test early stage sensitivity, and I showed that the parental environment of the mouthbrooder fish did not provide protection to embryos from acidified conditions. Enriched CO2 conditions exerted negative effects on the behaviour of their juvenile stage by increasing their anxiety. The distinct species-specific responses in physiology and behaviour have the potential to modify the distribution of phenotypical traits. I revealed that ocean acidification and warming can alter the phenotype distribution of risk taking behaviours (chapter 5). The redistribution of phenotypical traits has the potential to re-shape populations interactions as more dominant species are selected for under future conditions. Additionally, under naturally acidified and warming conditions I found that some species experience a loss of risk-taking phenotypes, as their phenotypic variability was reduced compared to the control conditions. This behavioural homogenisation puts populations of animals at risk to increasing global environmental change. The coping strategies that species use by adjusting their physiology and behaviour can enable them to maintain their fitness under climate change. If species maintain fitness during their entire life span and in future generations, then species will have a greater chance to persist under climatic disturbances. Understanding species sensitivity and their potential to acclimate to environmental change will help improve how we anticipate the future of adaptive capacity of organisms to warming and acidifying oceans.
Thesis (Ph.D.) -- University of Adelaide, School of Biological Sciences, 2020

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Частини книг з теми "Marine organisms sensitivity"

Hummel, Herman, Roelof Bogaards, Tatiana Bek, Lennard Polishchuk, Claude Amiard-Triquet, Guy Bachelet, Michel Desprez, et al. "Sensitivity to stress in the bivalve Macoma balthica from the most northern (Arctic) to the most southern (French) populations: low sensitivity in Arctic populations because of genetic adaptations?" In Interactions and Adaptation Strategies of Marine Organisms, 127–38. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-017-1907-0_13.

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Viarengo, A., B. Burlando, V. Evangelisti, S. Mozzone, and F. Dondero. "SENSITIVITY AND SPECIFICITY OF METALLOTHIONEIN AS A BIOMARKER FOR AQUATIC ENVIRONMENT BIOMONITORING." In Biomarkers in Marine Organisms, 29–43. Elsevier, 2001. http://dx.doi.org/10.1016/b978-044482913-9/50004-3.

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Riebesell, Ulf, and Philippe D. Tortell. "Effects of Ocean Acidification on Pelagic Organisms and Ecosystems." In Ocean Acidification. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199591091.003.0011.

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Over the past decade there has been rapidly growing interest in the potential effects of ocean acidification and perturbations of the carbonate system on marine organisms. While early studies focused on a handful of phytoplankton and calcifying invertebrates, an increasing number of investigators have begun to examine the sensitivity to ocean acidification of various planktonic and benthic organisms across the marine food web. Several excellent review articles have recently summarized the rapidly expanding literature on this topic (Fabry et al. 2008; Doney et al. 2009 ; Joint et al. 2011). The focus of this chapter is on the potential ecosystem-level effects of ocean acidification. Starting with a brief review of the basic physical, chemical, and biological processes which structure pelagic marine ecosystems, the chapter explores how organismal responses to perturbations of the carbonate system could scale up in both time and space to affect ecosystem functions and biogeochemical processes. As with many chapters in this volume, and indeed much of the ocean acidification literature at present, our review raises more questions than it answers. It is hoped that these questions will prove useful for articulating and addressing key areas of future research. Complexity in marine pelagic food webs results from the interactions of multiple trophic levels across a range of temporal and spatial scales. The traditional view of marine food webs (Steele 1974) involved a relatively short trophic system in which large phytoplankton (e.g. net plankton such as diatoms) were grazed by a variety of mesozooplankton (e.g. copepods), which were in turn consumed by second-level predators, including many economically important fish and invertebrate species. This ‘classic’ marine food web is typical of high-productivity regions such as coastal upwelling regimes (Lassiter et al. 2006). A characteristic feature of these systems is a strong decoupling between primary production and grazing, which results from the different metabolic rates of consumers and producers and, in many cases, ontogenetic and seasonal delays in the emergence of feeding predators. The uncoupling between phytoplankton and their consumers leads to significant export of organic material out of the euphotic zone, the so-called biological carbon pump (discussed further below).

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Rosenzweig, Cynthia, and Daniel Hillel. "Impacts of El Niño and La Niña Cycles: Systems and Sectors." In Climate Variability and the Global Harvest. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195137637.003.0007.

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Perturbations of the climate system caused by El Niño and La Niña events affect natural and managed systems in vast areas of the Pacific Ocean and far beyond it. (Other oscillations affect systems and sectors in wide swaths of the world as well.)1 El Niño–Southern Oscillation (ENSO) events have been associated with ecosystem disruptions and forest fires, crop failures and famines, disease epidemics, and even market fluctuations in various regions. The forms and degrees of impact depend not only on the strength and duration of an El Niño or La Niña event and its associated teleconnections, but also on the state, sensitivity, and vulnerability of the affected system and its biotic community, as well as its human population. The underlying characteristics of ecosystems and human societies in each region are important factors in their susceptibility to ENSO-related damages. Variation may be enhanced as ENSO effects ripple through natural and managed ecosystems. The underlying health of the affected biota, interrelationships among different biotic associations, and pressure by humans all affect marine as well as terrestrial ecosystem responses to ENSO events. Impacts on human systems can be both direct and indirect. Some ENSO phenomena, such as severe storms, affect human lives and infrastructures directly. Other impacts occur through alterations in the marine and terrestrial ecosystems and water supplies upon which human populations ultimately depend. In this chapter we consider some of the impacts that ENSO and other oscillations (described with their teleconnections in chapter 1) have on marine and terrestrial ecosystems and on human-managed systems apart from agriculture. The significant and geographically widespread changes that El Niño events induce in the Pacific Ocean alter conditions for various marine communities. These alterations include dramatic changes in the abundance and distribution of organisms, associated collapses of commercial fisheries, and ensuing consequences affecting human livelihood (Glantz, 2004; Lehodey et al., 2006). Some of the effects are well documented. Reductions in primary production of up to 95% were measured in the eastern equatorial Pacific in 1982–83 (Barber and Chavez, 1983.) Large changes in ecosystem structure and productivity have also been recorded in other parts of the Pacific Ocean, including the western Pacific and in the North Pacific subtropical gyre (north of the Hawaiian Islands) (Karl et al., 1995).

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Navarro-Barranco, Carlos, Macarena Ros, José M. Tierno de Figueroa, and José M. Guerra-García. "Marine Crustaceans as Bioindicators: Amphipods as Case Study." In Fisheries and Aquaculture, 436–62. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190865627.003.0017.

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A bioindicator species can be defined as “an organism that provides information on the environmental conditions of its habitat by its presence or absence, and its behavior.” In this sense, crustaceans present many biological and ecological characteristics that make them particularly useful as bioindicators (e.g., widespread distribution in different habitats and geographical areas, key role in community functioning, great diversity of life history strategies). Within Crustacea, the order Amphipoda has been considered an especially relevant and suitable group due to its direct development and its special sensibility to disturbances, among other reasons. Crustaceans can be used in biomonitoring studies in a wide variety of habitats (e.g., both soft- and hard-bottom substrata from intertidal to deep environments) and for different types of environmental stressors. An extensive amount of literature has reported the sensitivity of crustacean species to heavy metal contamination, sewage and desalination discharges, or engineering and aquaculture activities, among others. Special emphasis has been placed on the role of crustaceans in the most used indexes (e.g., AMBI, BENTIX, BOPA) developed to establish the environmental quality of European coastal and marine areas. Crustaceans are one of the groups with a higher contribution to those indexes, although their presence is not necessarily indicative of low environmental disturbances. Within amphipods, the importance of the family Caprellidae as a monitoring tool in environmental programs (e.g., trace metal or tributyltin pollution) is highlighted. Alien crustaceans can also play a pivotal role as bioindicators of anthropogenic pressures, and their likely influence on the accuracy of ecological assessment programs should be taken into account. Finally, there is an increasing need to improve our scarce taxonomic knowledge in many crustacean groups since that information is vital for the correct development of monitoring tools. Studies dealing with the species’ ecological and biological traits are also encouraged in order to understand the potential application of these species as bioindicators.

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"sequences allows for the design of PCR primer sets that specifically amplify the genes encoding the enzyme from DNA samples extracted from the natural environment (Henckel et al. 1999, Meyer et al. 1999, Mesarch et al. 2000). Although the PCR method is both specific and sensitive, such standard reactions are not quantitative. To obtain quantitative data from PCR-based analyses, statistical methods based on most probable number (MPN) estimations have been used (Wand et al. 1997). In MPN-PCR, DNA extracts are diluted before PCR amplification and limits are set on the number of genes in the sample by reference to known control dilutions. Another way to quantify PCR-amplified products for comparison is to include an internal control in the PCR reaction (Leser et al. 1995, Mesarch et al. 2000). Here, a known amount of target DNA is added to a PCR reaction containing DNA from the mixed microbial population. The known target DNA is complementary to the same primers and thus competes with the target sequences in the extracted DNA sample. By preparing a dilution series of the known and unknown DNA species, it is possible to quantify the amount of product produced from die complementary gene in the extracted DNA. The known DNA target can be generated by cloning the gene of interest or purifying the PCR-amplified product after which a deletion is introduced to give a differently sized PCR product. There exists many variations of the standard PCR technique. The sensitivity and specificity of the PCR may be improved by adopting a nested approach. The initial amplification is carried out with a pair of primers that are not organism-specific, whereafter a second round of amplification is conducted on the product using primers specific for an organism with target sites internal to the first primer pair (el Fantroussi et 1997, Levesque et al. 1997, Rheims and Stackebrandt 1999)." In Recent Advances in Marine Biotechnology, Vol. 8, 223. CRC Press, 2003. http://dx.doi.org/10.1201/9781482279986-16.

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"slowly growing natural populations. Various approaches have been adopted in order to improve the sensitivity. These have included the use of multiple probes labelled with a single fluor (Lee et al. 1993); or labelled with multiple fluors (Trebesius et al. 1994) and enzyme-linked probes or detection systems that allow signal amplification (Lebaron et al. 1997, Schonhuber et al. 1999). The latter indirect approach not only has the potential for signal amplification, but may also be used in natural samples showing high levels of autofluorescence. Any thorough identification method has to include positive and negative controls. False-positive results may either be caused by cells emitting autofluorescence upon excitation or by nonspecific binding of the probe to nontarget cells. Samples should therefore be checked for autofluorescence before hybridization and a negative control with a fluorescent oligonucleotide not complementary to rRNA has to be applied to check for sequence-independent nonspecific binding. Such non-specific binding may be due to interaction of the dye compound of the probe with hydrophobic cell components. Failures to detect cells containing target sequences (false-negatives) may originate from cells with either low cellular ribosome content or limited permeability of the cell periphery for the fluorescent probe (Manz et al. 1992). With the rapidly expanding database of 16S rRNA sequences, the problem of probe specificity has become more apparent and the design of probes is becoming increasingly difficult. These problems are also applicable to PCR and other oligonucleotide-dependent techniques. The problem of probe specificity may be overcome by using multiple specific oligonucleotide probes targeting different sites on the rRNA molecule and labelled with different fluorochromes. While a single oligonucleotide target sequence may be found in a number of related taxa, the probability that target sites for three designed oligonucleotides are found in a nontarget organism is, however, much reduced." In Recent Advances in Marine Biotechnology, Vol. 8, 232. CRC Press, 2003. http://dx.doi.org/10.1201/9781482279986-25.

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Тези доповідей конференцій з теми "Marine organisms sensitivity"

Ameryoun, Hamed, and Franck Schoefs. "Probabilistic Modeling of Roughness Effects Caused by Bio-Colonization on Hydrodynamic Coefficients: A Sensitivity Study for Jacket-Platforms in Gulf of Guinea." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11101.

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Nowadays, challenge for requalification of existing offshore platforms through the reassessment process leads to consider the importance of updating new information (e.g. environmental data, new regulations, etc.). Regarding to this information and depending on offshore fields, data of marine growth colonization is shown to have a dominant effect. This is a real challenge in the Gulf of Guinea that this study focuses on. Marine growth is known to cause adverse effects on the performance of offshore structures. Its presence can change the roughness and the diameter of structural members and hence change the level of hydrodynamic coefficients. Moreover, modifying the added mass can change the natural period and hence dynamic responses of structures. Even platforms with the best protection schemes against marine organisms will after few weeks at least few months start to be covered by various types of marine growth. Generally, it was also recognized that the most important source of loading exerted on offshore structures comes from hydrodynamic actions which are influenced by hydrodynamic coefficient values. The colonization process is very complex and results are in a large diversity of marine growth type (animal, vegetal — hard, soft) and species. This study therefore proposes a stochastic modeling of marine growth and the roughness of hard species based on Response Surface Methodology. A geometrical description of nth order of Stokes model, formed by a random linear combination of deterministic vectors is employed. Finally, the complexity level of roughness modeling is analyzed and the results are discussed.

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Schoefs, Franck, and Hamed Ameryoun. "Probabilistic Modeling of the Bio-Colonization Effects on Hydrodynamic Forces With Several Combinations of Sea-State Condition: A Study on Jacket-Platforms in the Gulf of Guinea." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11100.

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During the stage of designing or re-assessment of a jacket-type offshore structure, one of the most important phases is the re-evaluation of environmental loads, which are exerted by the waves, the wind and the currents, and updating the new data (e.g. meteocean, new regulation, structural damaging etc.). The former is mainly caused by the randomness or uncertainty nature of the marine environment as well as the presence of marine growth that makes the modeling of environmental loading more complicated. The general species of marine growth may be divided into two main categories: vegetable (e.g. algae) and animal (e.g. mussel, anemones, and corals). Indeed, the structures can be covered by many marine organisms quickly (in the first weeks). The influence of bio-colonization on an offshore structure can be measured at several levels: obstruct or prohibits a visual inspection of the subjacent support, cost of procedures of cleaning for oil industries and increasing the hydrodynamic forces on the structure. Considering the latter, loading change due screen effect and added mass are shown to be the most relevant. This study aims to provide a probabilistic modeling of marine growth colonization in the Gulf of Guinea. A physical matrix response surface is used in view to provide a probabilistic modeling of the environmental loading on Jacket type offshore structures for quasi-static behavior in the presence of marine growth. The paper focuses on uncertainty and sensitivity studies respecting to the effects of wave, wind-sea and currents.

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Pistora, Vladislav, and Milan Brumovsky. "PTS Benchmark Performed Within IAEA Coordinated Research Project 9." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77407.

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During the period 2005 – 2008, the Coordinated Research Project 9 (CRP 9) “Review and Benchmark of Calculation Methods for Structural Integrity Assessment of RPVs During PTS” was organised by the IAEA. The overall objective of this Coordinated Research Project was to perform benchmark deterministic calculations of a typical pressurised thermal shock (PTS) regime and finally to recommend the best practice for PTS assessment. The benchmark concerns the assessment of the reactor pressure vessel (RPV) resistance against fast fracture for events in the NPP leading to PTS. This assessment is based on the stress intensity factors KI for a postulated crack. The aim of the benchmark was to compare the results obtained by individual participants for well-defined task, to compare the results obtained when applying national codes requirements, and to assess the influence of individual parameters entering the analysis when performing a large set of sensitivity studies. Further aim of this benchmark was to create data which can be used for training of young specialists and for validation of their approach. The benchmark phase of CRP 9 comprised: • Definition of two separate benchmarks for generic WWER-440/213 and PWR-900 (3 Loop) designs, considering the Participants’ own experience and the results of previous international studies. • Basic case analysis of the benchmark problems and application of national code approaches. • Sensitivity studies to assess the impact of individual parameters on the assessment results. The basic (mandatory) case was defined uniquely (all input parameters precisely defined) to enable comparison of the results. Only effect of different models, methods of solving the problems or user effect can be source of the differences in the results, but not the difference in the input data (e.g. material properties, crack geometry, safety margins etc.). The extent and format of output data to be used for comparison were also well-specified. This paper describes the definition of the PTS benchmarks and some examples of the comparative results, like: • variation of temperature through the RPV wall thickness, • variation of stress through the RPV wall thickness, • KI and KIC in dependence on temperature, • variation of KI along crack front, • resulting maximum allowable transition temperature. Finally, it was concluded that the differences among the results were reasonably low and that the methods and models used by the participants can be used for integrity assessment of real RPVs.

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