Bibliografie tematiche / Hypoxie marine

Letteratura scientifica selezionata sul tema "Hypoxie marine"

Autore: Grafiati

Pubblicato: 22 giugno 2024

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Articoli di riviste sul tema "Hypoxie marine":

Plowman, Caitlin Q., Cynthia D. Trowbridge, John Davenport, Colin Little, Luke Harman e Rob McAllen. "Stressed from above and stressed from below: dissolved oxygen fluctuations in Lough Hyne, a semi-enclosed marine lake". ICES Journal of Marine Science 77, n. 6 (5 agosto 2020): 2106–17. http://dx.doi.org/10.1093/icesjms/fsaa108.

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Abstract Dissolved oxygen (DO) concentrations of the fully marine Lough Hyne, SW Ireland, were sampled in biologically different habitats between 2014 and 2019 to investigate the declining water quality in the marine reserve and the severity of oxidative stress on benthic communities. DO was measured above and below shallow subtidal rocks, in the Rapids connection to the Celtic Sea, in seagrass meadows (Zostera marina), and at various water depths (1–15 m) in the South Basin. DO values above rocks were normoxic to hyperoxic in daytime (7.8–17.3 mg l−1); below rocks were often hypoxic (0.24–2 mg l−1). South Basin sites experienced hypoxia less often than the North Basin, except for the Goleen, presumably due to differential current flow. DO fluctuations occurred in spring (before ephemeral macroalgae proliferate), summer (when algal mats smother the benthos), and autumn (when macroalgae decay). While the Rapids were normoxic, the seagrass meadows below them exhibited periodic DO stress. Labhra Cliff (9–14.5 m) was normoxic to hyperoxic in autumn but experienced suboxic and hypoxic events in summer. Many organisms in Lough Hyne are experiencing periods of hypoxia below their published sublethal limits, the effects of which could be exacerbated by periodic hyperoxia.

Vaquer-Sunyer, Raquel, e Carlos M. Duarte. "Thresholds of hypoxia for marine biodiversity". Proceedings of the National Academy of Sciences 105, n. 40 (29 settembre 2008): 15452–57. http://dx.doi.org/10.1073/pnas.0803833105.

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Hypoxia is a mounting problem affecting the world's coastal waters, with severe consequences for marine life, including death and catastrophic changes. Hypoxia is forecast to increase owing to the combined effects of the continued spread of coastal eutrophication and global warming. A broad comparative analysis across a range of contrasting marine benthic organisms showed that hypoxia thresholds vary greatly across marine benthic organisms and that the conventional definition of 2 mg O2/liter to designate waters as hypoxic is below the empirical sublethal and lethal O2 thresholds for half of the species tested. These results imply that the number and area of coastal ecosystems affected by hypoxia and the future extent of hypoxia impacts on marine life have been generally underestimated.

Hasler-Sheetal, Harald. "Detrimental impact of sulfide on the seagrass Zostera marina in dark hypoxia". PLOS ONE 18, n. 12 (7 dicembre 2023): e0295450. http://dx.doi.org/10.1371/journal.pone.0295450.

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Sulfide poisoning, hypoxia events, and reduced light availability pose threats to marine ecosystems such as seagrass meadows. These threats are projected to intensify globally, largely due to accelerating eutrophication of estuaries and coastal environments. Despite the urgency, our current comprehension of the metabolic pathways that underlie the deleterious effects of sulfide toxicity and hypoxia on seagrasses remains inadequate. To address this knowledge gap, I conducted metabolomic analyses to investigate the impact of sulfide poisoning under dark-hypoxia in vitro conditions on Zostera marina, a vital habitat-forming marine plant. During the initial 45 minutes of dark-hypoxia exposure, I detected an acclimation phase characterized by the activation of anaerobic metabolic pathways and specific biochemical routes that mitigated hypoxia and sulfide toxicity. These pathways served to offset energy imbalances, cytosolic acidosis, and sulfide toxicity. Notably, one such route facilitated the transformation of toxic sulfide into non-toxic organic sulfur compounds, including cysteine and glutathione. However, this sulfide tolerance mechanism exhibited exhaustion post the initial 45-minute acclimation phase. Consequently, after 60 minutes of continuous sulfide exposure, the sulfide toxicity began to inhibit the hypoxia-mitigating pathways, culminating in leaf senescence and tissue degradation. Utilizing metabolomic approaches, I elucidated the intricate metabolic responses of seagrasses to sulfide toxicity under in vitro dark-hypoxic conditions. My findings suggest that future increases in coastal eutrophication will compromise the resilience of seagrass ecosystems to hypoxia, primarily due to the exacerbating influence of sulfide.

Thomas, Peter, e Md Saydur Rahman. "Extensive reproductive disruption, ovarian masculinization and aromatase suppression in Atlantic croaker in the northern Gulf of Mexico hypoxic zone". Proceedings of the Royal Society B: Biological Sciences 279, n. 1726 (25 maggio 2011): 28–38. http://dx.doi.org/10.1098/rspb.2011.0529.

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The long-term impacts on marine ecosystems of the recent dramatic worldwide increase in the incidence of coastal hypoxia are unknown. Here, we show widespread reproductive disruption in Atlantic croakers collected from hypoxic sites approximately 120 km apart in the extensive northern Gulf of Mexico continental shelf hypoxic zone. Gonadal growth and gamete production were impaired in croakers from hypoxic sites compared with fish from reference normoxic sites east of the Mississippi River Delta. Male germ cells were detected in approximately 19 per cent of croaker ovaries collected in the hypoxic region, but were absent in ovaries from normoxic sites. In addition, the sex ratio was skewed towards males at the hypoxic sites. The masculinization and other reproductive disruptions were associated with declines in neuroendocrine function, as well as ovarian and brain expression of aromatase (the enzyme that converts androgens to oestrogens). A similar incidence of ovarian masculinization and decline in ovarian aromatase expression were observed in croaker after chronic laboratory hypoxia exposure, indicating that ovarian masculinization is a specific hypoxia response and is due to decreased aromatase activity. The results suggest severe reproductive impairment can occur over large coastal regions in marine fish populations exposed to seasonal hypoxia, with potential long-term impacts on population abundance.

Fennel, Katja, e Jeremy M. Testa. "Biogeochemical Controls on Coastal Hypoxia". Annual Review of Marine Science 11, n. 1 (3 gennaio 2019): 105–30. http://dx.doi.org/10.1146/annurev-marine-010318-095138.

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Aquatic environments experiencing low-oxygen conditions have been described as hypoxic, suboxic, or anoxic zones; oxygen minimum zones; and, in the popular media, the misnomer “dead zones.” This review aims to elucidate important aspects underlying oxygen depletion in diverse coastal systems and provides a synthesis of general relationships between hypoxia and its controlling factors. After presenting a generic overview of the first-order processes, we review system-specific characteristics for selected estuaries where adjacent human settlements contribute to high nutrient loads, river-dominated shelves that receive large inputs of fresh water and anthropogenic nutrients, and upwelling regions where a supply of nutrient-rich, low-oxygen waters generates oxygen minimum zones without direct anthropogenic influence. We propose a nondimensional number that relates the hypoxia timescale and water residence time to guide the cross-system comparison. Our analysis reveals the basic principles underlying hypoxia generation in coastal systems and provides a framework for discussing future changes.

Su, Jianzhong, Minhan Dai, Biyan He, Lifang Wang, Jianping Gan, Xianghui Guo, Huade Zhao e Fengling Yu. "Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in a large eutrophic estuary: the lower reach of the Pearl River Estuary, China". Biogeosciences 14, n. 18 (19 settembre 2017): 4085–99. http://dx.doi.org/10.5194/bg-14-4085-2017.

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Abstract. We assess the relative contributions of different sources of organic matter, marine vs. terrestrial, to oxygen consumption in an emerging hypoxic zone in the lower Pearl River Estuary (PRE), a large eutrophic estuary located in Southern China. Our cruise, conducted in July 2014, consisted of two legs before and after the passing of Typhoon Rammasun, which completely de-stratified the water column. The stratification recovered rapidly, within 1 day after the typhoon. We observed algal blooms in the upper layer of the water column and hypoxia underneath in bottom water during both legs. Repeat sampling at the initial hypoxic station showed severe oxygen depletion down to 30 µmol kg−1 before the typhoon and a clear drawdown of dissolved oxygen after the typhoon. Based on a three endmember mixing model and the mass balance of dissolved inorganic carbon and its isotopic composition, the δ13C of organic carbon remineralized in the hypoxic zone was −23.2 ± 1.1 ‰. We estimated that 65 ± 16 % of the oxygen-consuming organic matter was derived from marine sources, and the rest (35 ± 16 %) was derived from the continent. In contrast to a recently studied hypoxic zone in the East China Sea off the Changjiang Estuary where marine organic matter dominated oxygen consumption, here terrestrial organic matter significantly contributed to the formation and maintenance of hypoxia. How varying amounts of these organic matter sources drive oxygen consumption has important implications for better understanding hypoxia and its mitigation in bottom waters.

Joyce, William, Karlina Ozolina, Florian Mauduit, Hélène Ollivier, Guy Claireaux e Holly A. Shiels. "Individual variation in whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance in a marine teleost". Biology Letters 12, n. 1 (gennaio 2016): 20150708. http://dx.doi.org/10.1098/rsbl.2015.0708.

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Hypoxia is a pervasive problem in coastal environments and is predicted to have enduring impacts on aquatic ecosystems. Intraspecific variation in hypoxia tolerance is well documented in fish; however, the factors underlying this variation remain unknown. Here, we investigate the role of the heart in individual hypoxia tolerance of the European sea bass ( Dicentrarchus labrax ). We found individual whole-animal hypoxia tolerance is a stable trait in sea bass for more than 18 months (duration of study). We next examined in vitro cardiac performance and found myocardial muscle from hypoxia-tolerant individuals generated greater force, with higher rates of contraction and relaxation, than hypoxic-sensitive individuals during hypoxic exposure. Thus, whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance. As the occurrence of aquatic hypoxia is expected to increase in marine ecosystems, our experimental data suggest that cardiac performance may influence fish survival and distribution.

Keister, Julie E., Amanda K. Winans e BethElLee Herrmann. "Zooplankton Community Response to Seasonal Hypoxia: A Test of Three Hypotheses". Diversity 12, n. 1 (1 gennaio 2020): 21. http://dx.doi.org/10.3390/d12010021.

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Several hypotheses of how zooplankton communities respond to coastal hypoxia have been put forward in the literature over the past few decades. We explored three of those that are focused on how zooplankton composition or biomass is affected by seasonal hypoxia using data collected over two summers in Hood Canal, a seasonally-hypoxic sub-basin of Puget Sound, Washington. We conducted hydrographic profiles and zooplankton net tows at four stations, from a region in the south that annually experiences moderate hypoxia to a region in the north where oxygen remains above hypoxic levels. The specific hypotheses tested were that low oxygen leads to: (1) increased dominance of gelatinous relative to crustacean zooplankton, (2) increased dominance of cyclopoid copepods relative to calanoid copepods, and (3) overall decreased zooplankton abundance and biomass at hypoxic sites compared to where oxygen levels are high. Additionally, we examined whether the temporal stability of community structure was decreased by hypoxia. We found evidence of a shift toward more gelatinous zooplankton and lower total zooplankton abundance and biomass at hypoxic sites, but no clear increase in the dominance of cyclopoid relative to calanoid copepods. We also found the lowest variance in community structure at the most hypoxic site, in contrast to our prediction. Hypoxia can fundamentally alter marine ecosystems, but the impacts differ among systems.

Kraus, Richard T., Carey T. Knight, Troy M. Farmer, Ann Marie Gorman, Paris D. Collingsworth, Glenn J. Warren, Patrick M. Kocovsky e Joseph D. Conroy. "Dynamic hypoxic zones in Lake Erie compress fish habitat, altering vulnerability to fishing gears". Canadian Journal of Fisheries and Aquatic Sciences 72, n. 6 (giugno 2015): 797–806. http://dx.doi.org/10.1139/cjfas-2014-0517.

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Seasonal degradation of aquatic habitats from hypoxia occurs in numerous freshwater and coastal marine systems and can result in direct mortality or displacement of fish. Yet, fishery landings from these systems are frequently unresponsive to changes in the severity and extent of hypoxia, and population-scale effects have been difficult to measure except in extreme hypoxic conditions with hypoxia-sensitive species. We investigated fine-scale temporal and spatial variability in dissolved oxygen in Lake Erie as it related to fish distribution and catch efficiencies of both active (bottom trawls) and passive (trap nets) fishing gears. Temperature and dissolved oxygen loggers placed near the edge of the hypolimnion exhibited much higher than expected variability. Hypoxic episodes of variable durations were frequently punctuated by periods of normoxia, consistent with high-frequency internal waves. High-resolution interpolations of water quality and hydroacoustic surveys suggest that fish habitat is compressed during hypoxic episodes, resulting in higher fish densities near the edges of hypoxia. At fixed locations with passive commercial fishing gear, catches with the highest values occurred when bottom waters were hypoxic for intermediate proportions of time. Proximity to hypoxia explained significant variation in bottom trawl catches, with higher catch rates near the edge of hypoxia. These results emphasize how hypoxia may elevate catch rates in various types of fishing gears, leading to a lack of association between indices of hypoxia and fishery landings. Increased catch rates of fish at the edges of hypoxia have important implications for stock assessment models that assume catchability is spatially homogeneous.

Seitaj, Dorina, Regina Schauer, Fatimah Sulu-Gambari, Silvia Hidalgo-Martinez, Sairah Y. Malkin, Laurine D. W. Burdorf, Caroline P. Slomp e Filip J. R. Meysman. "Cable bacteria generate a firewall against euxinia in seasonally hypoxic basins". Proceedings of the National Academy of Sciences 112, n. 43 (7 ottobre 2015): 13278–83. http://dx.doi.org/10.1073/pnas.1510152112.

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Seasonal oxygen depletion (hypoxia) in coastal bottom waters can lead to the release and persistence of free sulfide (euxinia), which is highly detrimental to marine life. Although coastal hypoxia is relatively common, reports of euxinia are less frequent, which suggests that certain environmental controls can delay the onset of euxinia. However, these controls and their prevalence are poorly understood. Here we present field observations from a seasonally hypoxic marine basin (Grevelingen, The Netherlands), which suggest that the activity of cable bacteria, a recently discovered group of sulfur-oxidizing microorganisms inducing long-distance electron transport, can delay the onset of euxinia in coastal waters. Our results reveal a remarkable seasonal succession of sulfur cycling pathways, which was observed over multiple years. Cable bacteria dominate the sediment geochemistry in winter, whereas, after the summer hypoxia,Beggiatoaceaemats colonize the sediment. The specific electrogenic metabolism of cable bacteria generates a large buffer of sedimentary iron oxides before the onset of summer hypoxia, which captures free sulfide in the surface sediment, thus likely preventing the development of bottom water euxinia. As cable bacteria are present in many seasonally hypoxic systems, this euxinia-preventing firewall mechanism could be widely active, and may explain why euxinia is relatively infrequently observed in the coastal ocean.

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Tesi sul tema "Hypoxie marine":

Vanderplancke, Gwenaëlle. "Conséquences à long terme d'une exposition précose à l'hypoxie sur la physiologie du bar européen (Dicentrarchus labrax) et de la sole commune (Solea solea)". Thesis, Brest, 2015. http://www.theses.fr/2015BRES0006/document.

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L’oxygène dissous dans l’eau de mer a régulièrement baissé dans de nombreux écosystèmes marins côtiers ces 50 dernières années du fait du réchauffement climatique et des activités humaines côtières croissantes. Cette diminution de l’oxygène présent dans l’eau de mer provoque des épisodes d’hypoxie de plus en plus fréquents et sévères dans les zones côtières et estuariennes. Certains organismes peuvent échapper à ces contraintes environnementales par migration ou dispersion. D’autres, présentant des capacités de nages plus réduites, doivent mettre en oeuvre des régulations physiologiques (plasticité phénotypique) pour leur permettre de s’adapter et survivre. C’est notamment le cas des larves de poissons marins qui sont susceptibles d’être présentes dans les nourriceries côtières à la fin de leur développement. Il est aujourd’hui bien établi que les régulations mises en oeuvre par les organismes pour faire face à leur environnement durant les jeunes stades de vie peuvent imprégner leur fonctionnement physiologique sur le long-terme et modifier leur trajectoire de vie. Si de nombreuses informations relatives aux conditionnements précoces sont disponibles dans le domaine médical, les connaissances de ces effets chez les organismes marins dans un contexte écologique sont encore très fragmentaires. L’objectif principal de ce travail de thèse a donc été d’évaluer les conséquences physiologiques, non seulement à court-terme mais surtout à long-terme, d’une exposition de poissons marins en fin de développement larvaire à une hypoxie modérée (8 jours, 40% de saturation à l’air). L’autre originalité de ce travail reposait sur la comparaison des réponses adaptatives mises en oeuvre chez deux espèces, l’une pélagique ─ le bar Européen (Dicentrarchus labrax) ─ et l’autre benthique ─ la sole commune (Solea solea). Nos résultats nous ont permis de montrer un effet significatif à long-terme de la contrainte hypoxique précoce sur les performances physiologiques des juvéniles et notamment sur leur croissance. Les juvéniles de bars et de soles présentent respectivement de plus faibles et de plus fortes croissances après avoir été exposés à un environnement hypoxique au stade larvaire. L’effet négatif sur la croissance observé chez le bar s’explique, au moins en partie, par une moins bonne assimilation énergétique due à un impact sur la fonction digestive. Les analyses moléculaires réalisées au niveau hépatique chez le juvénile de bar révèlent, par ailleurs, une imprégnation au niveau transcriptionnel de l’expression de gènes impliqués dans la réponse à l’hypoxie. L’effet positif observé sur la croissance des juvéniles de sole est associé à une meilleure tolérance aux stress thermiques et hypoxiques et à une diminution du registre métabolique. Les résultats obtenus chez le bar et la sole suggèrent que des modifications d’allocations énergétiques sous-tendent les effets observés à long-terme sur les performances physiologiques. Plus globalement, l’ensemble des données obtenues au cours de cette thèse soutiennent l’importance que revêt la nature de l’environnement rencontré par le poisson au cours de ses jeunes stades de vie sur ses futures performances physiologiques. Nos résultats indiquent par ailleurs que l’imprégnation physiologique par l’environnement est espèce-spécifique révélant des probables stratégies d’adaptation différentes suivant les espèces
The dissolved oxygen in seawater has steadily declined in many coastal marine ecosystems in the last 50 years because of global warming and increasing coastal human activities. This decrease in oxygen in seawater causes episodes of hypoxia increasingly frequent and severe in coastal and estuarine areas. Some organisms may escape these environmental constraints by migration or dispersion. Others, with limited swimming capabilities must implement physiological regulation (phenotypic plasticity) to enable them to adapt and survive. This is particularly the case of marine fish larvae that are likely to be present in coastal nursery at the end of their development. It is now well established that the regulations implemented by organisms to cope with their environment during the early stages of life can imprint their physiological function in the long-term and change their life trajectory. While much information on early conditioning is available in the field of medicine, knowledge of these effects in marine organisms in an ecological context are still very fragmentary. Therefore, the main objective of this thesis was to evaluate the physiological consequences, not only in the short-term but especially in the long-term, of an exposition to a moderate hypoxia (8 days, 40% air saturation) of marine fish at the end of larval development. Another originality of this work was based on the comparison of adaptive responses implemented in two species, one pelagic ─ European sea bass (Dicentrarchus labrax) ─ and one benthic ─ the common sole (Solea solea). Our results have allowed us to show a significant long-term effect of early hypoxic stress on the physiological performance of juvenile and especially their growth. Juveniles of European sea bass and juveniles of common sole have, respectively, lower and higher growth after being exposed to a hypoxic environment in the larval stage. The negative effect on growth observed in sea bass was due, in part, to lower energy assimilation as a consequence of an impact on the digestive function. Moreover, molecular analyzes in the liver of sea bass juveniles indicate an impregnation at the transcriptional level of the expression of genes involved in the response to hypoxia. The positive effect observed on the growth of sole juveniles is associated with better tolerance to thermal and hypoxic stress and a decrease in metabolic scope. The results obtained in European sea bass and common sole suggest that changes in energy allocations could explain the physiological performances observed in the long-term. Globally, all the data obtained in this thesis underline the importance of the environmental parameters encountered by fish during their young life stages on their future physiological performances. Such physiological impregnation by the early environment is species-specific, revealing potential different adaptation strategies

李嵐 e Laam Li. "Effects of hypoxia on marine benthic communities : from bacteria to invertebrates". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193402.

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Because of the eutrophication resulting from increasing anthropogenic activities, hypoxia (i.e. dissolved oxygen < 2.8 mg O2 L-1) is on the rise globally. The objective of this research was to understand more about the effects of hypoxia on the marine benthic communities. Particularly, it focused on the latent effects and indirect effects of hypoxia by investigating how early exposure to hypoxia affect the later life stage of a marine gastropod Crepidula onyx, and how hypoxia alter the bacterial composition of biofilms and the subsequent larval settlement of marine invertebrates. In the first study, the larvae of C. onyx were exposed to 2, 3, and 6 mg O2 l-1. Under low food concentration (Isochrysis galbana at 1 × 105 cells l-1), larvae in both hypoxic treatments (2 and 3 mg O2 l-1) required a longer time to become competent to metamorphose. But when they did, they had a similar size and total lipid content to the control larvae. Moreover, the latent effects of early hypoxic exposure on the juvenile growth were evident. After 2 weeks development in field, the growth rate, mean dry weight and filtration rate of juveniles were significantly reduced in the hypoxic treatments. However, there was no discernible effect on larvae or juveniles when the food concentration during the larval stage was doubled (I. galbana at 2 × 105 cells l-1), suggesting that the latent effects of hypoxia can be offset by larval access to high algal concentration. In the second study, the biofilms were exposed to hypoxia and normoxia in microcosms for up to 7 days, and their bacterial community composition was analysed by terminal-restriction fragment length polymorphism (T-RFLP). The results suggested that hypoxia altered the bacterial community structure within biofilms, and the difference between the hypoxia and normoxia treatments increased through the length of exposure period. The resulting changes in biofilms did not alter the larval settlement response of a model species (i.e. C. onyx) in laboratory assays. Nevertheless, when the biofilms were deployed in the field to allow natural larval settlement and recruitment, biofilms that had been exposed to hypoxia altered the overall larval settlement pattern of different marine invertebrates, potentially leading to a shift in the benthic invertebrate community. This research suggested that periodic hypoxic events and the resulting exposure of organisms to hypoxia during their early development might have effects that persist across the life history. Moreover, it highlighted the possibility that the effects of hypoxia on species composition and structure of benthic invertebrate communities might be mediated through changes in biofilms and subsequently larval settlement and recruitment. To conclude, this research demonstrated that hypoxia could affect the growth in the later life stages of marine invertebrates and the recruitment of the benthic communities.
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Biological Sciences
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Master of Philosophy

Nestlerode, Janet A. "Effects of Periodic Environmental Hypoxia on Predator Utilization of Macrobenthic Infauna". W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539617700.

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Hypoxia and anoxia have significant deleterious ecological effects on living resources throughout many estuarine and marine ecosystems worldwide. Brief periods of low oxygen facilitate transfer of benthic production to higher trophic levels as many benthic infaunal species have shallower sediment depth distributions during hypoxic events. A baited time-lapse camera equipped with a water quality datalogger was used to document in situ exploitation of oxygen-stressed benthic invertebrate prey organisms by mobile fish and crustacean predators during alternating normoxia-hypoxia cycles in the York River. Based on photographic and diver observations, this hypoxiainduced benthic-pelagic transfer of production is more likely to occur when environmental dissolved oxygen concentrations rise above an apparent threshold between 1 and 2 ml/1. When oxygen concentrations decline below 2 ml/1, the functional response of the predator to increased prey availability is interrupted. There is no energy gain by the predator until oxygen concentrations rise above this critical level when predators return to affected areas and resume feeding activity.

Artigaud, Sébastien. "Approche intégrative de la réponse d'un organisme marin face au changement climatique : la coquille Saint-Jacques Pecten maximus et les stress thermique et hypoxique". Thesis, Brest, 2013. http://www.theses.fr/2013BRES0078/document.

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Les écosystèmes côtiers sont parmi les plus vulnérables aux changements globaux actuels, qui entraînent notamment une augmentation de la température de l'eau, ainsi que de la fréquence des épisodes hypoxiques. La coquille Saint-Jacques, Pecten maximus, est une espèce subtidale évoluant à des profondeurs de 2 à 210 m. Malgré son intérêt commercial et un intérêt écologique majeur, cette espèce n'a fait l'objet que de peu d'études au niveau moléculaire. L'objectif de cette thèse était de caractériser les mécanismes moléculaires régissant l'acclimatation de cette espèce aux contraintes thermique et hypoxique. Nous avons dans un premier temps caractérisé les modifications d'expression des gènes/protéines, par des approches transcriptomiques (RNAseq) et protéomiques (2-DE), dans un tissu, le manteau, d'animaux exposés à une contrainte thermique prolongée (56 jours). Nous avons ainsi pu identifier les voies majeures de régulation (eg., AP-1), les grandes fonctions (eg., cytosquelette) et processus (eg., apoptose) impliqués dans la réponse, mais également d'observer les grandes orientations du métabolisme (eg., dégradation des lipides de réserve). La réponse des organismes à l'hypoxie dépend de leur manière de gérer les faibles teneurs en oxygène. Nous avons d'abord, par une approche comparative avec une espèce intertidale, la moule (Mytilus spp.), caractérisée la réponse physiologique de la coquille Saint-Jacques à l'hypoxie. Nous avons pu ainsi déterminer ses paramètres d'oxyregulation, plus particulièrement son Point critique en 02 (Pc02). Le développement d'une approche protéomique, couplant l'effet de la température et de l'hypoxie, nous a ensuite permis d'identifier plusieurs protéines (CK2, GLN, etc.) potentiellement impliquées dans la réponse au niveau moléculaire. Enfin, dans l'optique de mieux comprendre la physiologie particulière de ces mollusques dans leur environnement naturel, nous avons comparé les signatures protéomiques de deux populations de P. maximus évoluant dans des écosystèmes contrastés, i.e. en limite nord- (Norvège) et au centre- (Brest) de l'aire de répartition de l'espèce. Les résultats suggèrent des différences majeures entre les deux populations au niveau du cytosquelette. En conclusion, ce travail ouvre des perspectives nouvelles pour la compréhension des mécanismes moléculaires régissant l'adaptation des mollusques aux contraintes thermiques et hypoxiques, deux stress particulièrement importants pour les organismes marins dans le contexte du changement global
Coasts are among the most vulnerable ecosystems to the ongoing global changes, which result in increased water temperatures and frequencies of hypoxic episodes. The great scallop, Pecten maximus, is a subtidal species living at depths of 2-210 m. In spite of its commercial and major ecological values, only few studies at the molecular level were performed on this species. This thesis aimed at characterizing the molecular mechanisms implied in acclimation of this species to thermal and hypoxia stresses. We first characterized the changes of expression of the genes / proteins in response to a long-term thermal stress (56 days), by using both a transcriptomic- (RNAseq) and a proteomic- (2-DE based) approaches, in the mantle tissue of scallops. This allowed us to identify key regulatory pathways (eg., AP-1), the major functions (eg., cytoskeleton) and processes (eg., apoptosis) involved in the response, but also to observe the main orientations of metabolism (eg., degradation of lipid reserves). The response of organisms to hypoxia depends on how they cope with low oxygen availability. Therefore, we first carried out a comparative approach with an intertidal species, the mussel (Mytilus spp.) to characterize the physiological response of P. maximus to hypoxia. Of note, we could determine its oxyregulatory parameters, particularly its critical point in 02 (Pc02). Then, coupling the effects of temperature and of hypoxia, we developed a proteomic approach that allowed us to identify several proteins (CK2, GLN, etc.) potentially involved in the response at the molecular level. Finally, in an effort to better understand the particular physiology of these mollusks in their natural environment, we compared the proteomic signatures of two populations of P. maximus living in highly contrasted ecosystems, ie in the northern limit- (Norway) and the center- (Brest) of the biogeographical distribution of this species. The results suggest major differences between the two populations, especially at the cytoskeleton level. In all, this work opens new avenues for understanding the molecular mechanisms governing the adaptation of mollusks to heat and hypoxia, two stresses that will most probably greatly influence the lifestyle of marine organisms and populations in future years

Da, Fei. "Impacts of Atmospheric Nitrogen Deposition and Coastal Nitrogen Fluxes on Chesapeake Bay Hypoxia". W&M ScholarWorks, 2018. https://scholarworks.wm.edu/etd/1530192498.

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Although rivers are the primary source of dissolved inorganic nitrogen (DIN) inputs to the Chesapeake Bay, direct atmospheric DIN deposition and DIN fluxes from the continental shelf can also significantly impact Chesapeake Bay hypoxia. The relative role of these additional sources of DIN has not previously been thoroughly quantified. In this study, the three-dimensional Estuarine-Carbon-Biogeochemistry model embedded in the Regional Ocean Modeling System (ChesROMS-ECB) is used to examine the relative impact of these three DIN sources. Model simulations highlight that DIN inputs from the atmosphere have roughly the same impact on hypoxia as the same gram for gram change in riverine DIN loading. DIN inputs from the shelf have a similar overall impact on hypoxia as those from the atmosphere (~0.2 mg L-1), however the mechanisms driving these impacts are different. While atmospheric DIN impacts dissolved oxygen (DO) primarily via the decomposition of autochthonous organic matter, coastal DIN also impacts DO via the decomposition of allochthonous organic matter entering the Bay from the continental shelf. The impacts of coastal and atmospheric DIN on estuarine hypoxia are greatest in the summer, and occur farther downstream (lower mesohaline) in wet years than in dry years (upper mesohaline). Integrated analyses of the relative contributions of all three DIN sources on summer bottom DO concentrations indicate that impacts of atmospheric deposition are largest in shallow near-shore regions, riverine DIN has dominant impacts in the largest tributaries and the oligohaline Bay, while coastal DIN fluxes are most influential in the polyhaline region. During the winter when estuarine circulation is strong and shelf DIN concentrations are relatively high, coastal DIN impacts bottom DO throughout the Bay.

Ogino, Tetsuya. "Environmental adaptation mechanism in marine annelids". Kyoto University, 2019. http://hdl.handle.net/2433/242707.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21830号
農博第2343号
新制||農||1068(附属図書館)
学位論文||H31||N5202(農学部図書室)
京都大学大学院農学研究科応用生物科学専攻
(主査)教授佐藤健司, 教授澤山茂樹, 准教授豊原治彦
学位規則第4条第1項該当

Damerval, Marc. "Identification et rôle physiologique des inclusions contenues dans le système nerveux central de la moule Mytilus edulis et de la crépidule Crepidula fornicata". Caen, 1985. http://www.theses.fr/1985CAEN2004.

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Les inclusions des cellules gliales et des neurones des ganglions cérébroïdes de crépidule et cérépleuraux de la moule ont été examinés. Une première approche a permis de distinguer les granules de neurosécretion de type neuroendocrine des inclusions pigmentées. L'ultrastructure de ces inclusions permet de les caracteriser avec précision. L'étude biochimique révèle la présence de carotènes et de différentes xanthophylles. On précise enfin le rôle de ces inclusions dans des conditions d'hypoxie et d'anoxie du milieu

Morell, Alaia. "Dynamiques éco-évolutives des espèces exploitées en Mer du Nord en réponse à des variations biotiques et abiotiques de l'environnement". Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR079.

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Les scénarios de changements globaux sont précieux pour guider les stratégies de gestion et de gouvernance, inciter à la prise de décision et augmenter la prise de conscience collective des tendances futures de la biodiversité. Le degré de réalisme et d'intégration des modèles écosystémiques utilisés à cet effet est en constante progression, mais ils négligent encore souvent l'évolution des populations marines dans les projections futures. Or, celles-ci s'adaptent aux changements globaux, que ce soit par la plasticité phénotypique ou l'évolution, au travers de modifications de leurs caractéristiques biologiques telles que les traits d'histoire de vie, physiologiques et bioénergétiques. L'enjeu de cette thèse est de développer un modèle écosystémique qui permette d'explorer des scénarios de biodiversité aux échelles intra- et inter-spécifiques en représentant explicitement la plasticité phénotypique des traits d'histoire de vie, leur variabilité génétique, leur sélection et leur évolution sous l'influence combinée de la pêche et du changement climatique, ainsi que la dérive génétique et la perte de diversité génétique qui en résultent. Appliqué à la mer du Nord, ce nouveau modèle est utilisé pour comprendre les processus responsables des changements de traits d'histoire de vie qu'ils soient d'origine plastique ou d'origine évolutive. D'une part, les processus bioénergétiques sous-jacents aux changements plastiques sont étudiés par une approche originale comparant les différences entre les courbes de réponses thermiques fondamentales et réalisées pour différentes espèces et stades du cycle de vie. D'autre part, les changements des traits d'histoire de vie sont explorés à travers le prisme de l'évolution grâce à la prise en compte de pressions de sélection multiples telles que la pêche, les interactions proies-prédateurs et le changement climatique.L'intégration des processus plastiques et évolutifs dans les modèles écosystémiques permet de décrire la variabilité interindividuelle des traits biologiques et de comprendre leurs tendances temporelles observées dans le milieu marin. En cela, elle répond à l'enjeu crucial de crédibilité des projections de la biodiversité intra- et inter-spécifique sous scénarios combinant climat et pêche. L'intégration de ces processus permettra également de quantifier plus précisément les effets synergiques et antagonistes de ces deux pressions et de prendre en compte la capacité d'adaptation des populations aux changements globaux pour estimer de manière plus fiable leur résilience
Global change scenarios are valuable for guiding management and governance strategies, stimulating decision making, and increasing collective awareness of future biodiversity trends. The degree of realism and integration of ecosystem models used for this purpose is constantly improving, but they still often neglect the evolution of marine populations in future projections. However, marine populations adapt to global changes, either through phenotypic plasticity or evolution, through modifications of their biological characteristics such as life history traits, physiological and bioenergetic traits. The challenge of this thesis is to develop an ecosystem model that allows the exploration of biodiversity scenarios at intra- and inter-specific scales by explicitly representing the phenotypic plasticity of life history traits, their genetic variability, selection and evolution under the combined influence of fisheries and climate change, and the resulting genetic drift and loss of genetic diversity. Applied to the North Sea, this new model is used to understand the processes responsible for changes in life history traits, whether they are of plastic or evolutionary origin. On the one hand, the bioenergetic processes underlying plastic changes are studied by an original approach comparing the differences between the fundamental and realized thermal response curves for different species and life history stages. On the other hand, changes in life history traits are explored through an evolutionary lens by taking into account multiple selection pressures such as fishing, prey-predator interactions and climate change.The integration of plastic and evolutionary processes in ecosystem models allows to describe the inter-individual variability of biological traits and to understand their temporal trends observed in the marine environment. In this way, it responds to the crucial issue of credibility of intra- and inter-specific biodiversity projections under scenarios combining climate and fisheries. The integration of these processes will also allow to quantify more precisely the synergistic and antagonistic effects of these two pressures and to take into account the capacity of populations to adapt to global changes in order to estimate more reliably their resilience

Plante, Audrey. "Marine benthic hypoxia and its consequences for sediment-water exchanges and early diagenesis". Doctoral thesis, Universite Libre de Bruxelles, 2020. https://dipot.ulb.ac.be/dspace/bitstream/2013/312521/4/Thesis.pdf.

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The northwestern (NW) continental shelf of the Black Sea undergoes seasonal hypoxia. The benthic environment, the exchanges at the water-sediment interface and the diagenetic reactions are influenced by this phenomenon. In the framework of the BENTHOX project, two field cruises were conducted on the shelf in spring 2016 and in summer 2017.The first part of this investigation concerned the study of the impact of low oxygen levels in bottom waters on the diagenetic reactions. The microprofilings of geochemical parameters and the flux measurements showed both spatial and temporal variabilities in the benthic compartment of the NW continental shelf for the two seasons studied. The areas closest to the coasts exhibited the most important fluxes of oxygen consumption and of sulfate. These regions were strongly influenced by riverine inputs inducing a higher productivity and in turn resulting in an increase in the fluxes of organic matter deposited on the seabed.The diagenetic reactions were impacted by seasonal deoxygenation in bottom waters. The oxic respiration was less important in the summer as reflected by the shallower penetration depth of dissolved oxygen. Since 1995, the diffusive oxygen uptake (DOU) reported during hypoxic period indicated that the concentration of dissolved oxygen played an important role in the benthic exchange fluxes. Furthermore, a shallower reduction of sulphate and of Mn- and Fe-oxides observed in the sediments evidenced the impact of low oxygen levels on the diagenetic cascade. As a consequence, the benthic mineralization of organic matter was affected. During summer 2017, the oxic mineralization of organic carbon was less important and the contribution of the reducing species to oxygen consumption increased. The anaerobic mineralization of organic matter became thus the dominant process during the period of deoxygenation.The second part concerned the study of the sulfur and iron cycling in the shelf sediments during the low oxygen event of summer 2017. The sediments from the station close to the mouth of the Danube and that near the Dnieper exhibited a signature of detrital material different from that of the upper crust. The inputs of organic matter, in particular transported by the rivers, could influence the signal. The sediments of the NW shelf investigated were however of marine origin.Following the sulfate reduction already observed and mentioned above, the hydrogen sulfides produced were rapidly consumed as suggested by the low concentrations of acid volatile sulfide (AVS) and of the dissolved sulfide. The presence of pyrite in the upper layers of the sediments close to the water-sediment interface was plausible because the formation of pyrite in the water column had been reported due to the higher resistance of pyrite to oxidation compared to AVS (Wijsman et al. 2001). A non steady-state deposition was observed as suggested by Wijsman et al. (1999). It was characterized by an abrupt drop in the pyrite content caused possibly by fluctuations in salinity, dissolved O2 concentrations and organic matter fluxes.The non-reactive iron constituted the principal fraction of the total iron present in the sediments. Its contribution fell in the range reported for the marine sediments of the continental margins. A spatial variation of the concentration of highly reactive iron was nevertheless observed. Near the Dnieper mouth, the contents of reactive iron were lower and could be attributed to the less important fluvial inputs, to the sorption and/or precipitation processes or yet to the reallocation of the reactive iron of the shelf deposits towards the sediments in deep and euxinic waters.The last part of this thesis concerned the biogeochemistry of metals (Fe, Mn, Zn, Cu, Ni, Hg, Co and Cd) during the early diagenesis and the assessment of enrichment and pollution of these metals in the sediments of the shelf. The results showed that trace metals are probably linked to iron and manganese oxides as well as to sulphides. Ni and Zn could be involved in adsorption onto and co-precipitation with Fe- and Mn-oxides. Cu seemed to be associated preferentially to sulphides but no clear correlation was found. The enrichment and pollution of these metals in the shelf sediments showed spatial variability. The Danube delta area was enriched in Ni, Cu and Zn while the Odessa region was enriched in Co and Cd. The pollution of shelf sediments ranged from “unpolluted” to “very highly polluted”. Since the late 20th century, the heavy metal contents in shelf sediments remained stable in the Odessa region but increased in the Danube delta area.
Le plateau continental du Nord-Ouest de la Mer Noire subit une hypoxie saisonnière. L'environnement benthique, l'échange à l'interface eau-sédiment et les réactions diagénétiques sont influencés par ce phénomène. Dans le cadre du projet BENTHOX, deux campagnes de prélèvement ont été menées sur le plateau au printemps 2016 et à l'été 2017 dans le but de comprendre ces changements.La première partie de cette recherche concerne l’impact des faibles concentrations en oxygène dans les eaux de fond sur les réactions diagénétiques. Les micro-profils de paramètres géochimiques et les mesures de flux ont montré des variabilités spatiales et temporelles dans le compartiment benthique pour les deux saisons étudiées. Les zones les plus proches des côtes ont présenté les flux les plus importants de consommation d'oxygène et de sulfate. Ces régions ont été fortement influencées par les apports fluviaux induisant une productivité plus élevée et entraînant à son tour une augmentation des flux de matière organique déposée sur le fond marin. Les réactions diagénétiques sont affectées par la désoxygénation saisonnière des eaux de fond. La respiration oxique etait moins importante en été comme en témoigne la profondeur de pénétration moins profonde de l’oxygène. Depuis 1995, l’absorption d’oxygène dissous (DOU) rapportée pendant la période limitée en oxygène a indiqué que la concentration d'oxygène dissous jouait un rôle important dans les flux d'échanges benthiques. De plus, une diminution de la profondeur à laquelle la réduction des sulfates et la réduction des oxydes métalliques témoigne de l'impact d'une faible concentration en oxygène sur la cascade diagénétique. En conséquence, la minéralisation benthique de la matière organique a été affectée. Au cours de l'été 2017, la minéralisation oxique du carbone a été moins importante et la contribution des espèces réductrices à la consommation d’oxygène a augmenté. La respiration anaérobie de la matière organique est ainsi devenue le processus dominant pendant la période d'hypoxie.La deuxième partie portait sur l'étude du cycle du soufre et du fer dans les sédiments du plateau lors de l'événement de faible teneur en oxygène de l'été 2017. Les sédiments de la station proche de l'embouchure du Danube et de celle du Dniepr présentaient une signature de matière détritique différente de celle de la croûte supérieure. Les apports de matière organique, notamment transportés par les rivières, pourraient influencer le signal. Les sédiments du plateau nord-ouest étudiés étaient cependant d'origine marine. Suite à la réduction du sulfate déjà observée et mentionnée ci-dessus, les sulfures d'hydrogène produits ont été rapidement consommés comme le suggèrent les faibles concentrations en sulfure acide volatil (AVS) et en sulfure dissous. La présence de pyrite dans les couches supérieures des sédiments près de l'interface eau-sédiment était plausible car la formation de pyrite dans la colonne d'eau avait été signalée en raison de la résistance plus élevée de la pyrite à l'oxydation par rapport à l'AVS (Wijsman et al. 2001). Un dépôt à l'état non stationnaire a été observé comme le suggèrent Wijsman et al. (1999). Elle a été caractérisée par une chute brutale de la teneur en pyrite causée peut-être par des fluctuations de salinité, des concentrations d'O2 dissous et des flux de matière organiqueLe fer non réactif constituait la fraction principale du fer total présent dans les sédiments. Sa contribution est tombée dans la gamme signalée pour les sédiments marins des marges continentales. Une variation spatiale de la concentration en fer hautement réactif a néanmoins été observée. Près de l'embouchure du Dniepr, les teneurs en fer réactif étaient plus faibles et pouvaient être attribuées aux apports fluviaux moins importants, aux processus de sorption et / ou de précipitation ou encore à la réallocation du fer réactif des dépôts du plateau vers les sédiments en profondeur et eaux euxiniques.La dernière partie de cette thèse concerne la biogéochimie des métaux (Fe, Mn, Zn, Cu, Ni, Hg, Co et Cd) lors de la diagenèse précoce et l'évaluation de l'enrichissement et de la pollution de ces métaux dans les sédiments du plateau. Les résultats ont montré que les métaux traces sont probablement liés aux oxydes de fer et de manganèse ainsi qu'aux sulfures. Ni et Zn pourraient être impliqués dans l'adsorption et la coprécipitation avec les oxydes de Fe et de Mn. Le Cu semble être associé préférentiellement aux sulfures mais aucune corrélation claire n'a été trouvée. L'enrichissement et la pollution de ces métaux dans les sédiments du plateau ont montré une variabilité spatiale. La zone du delta du Danube a été enrichie en Ni, Cu et Zn tandis que la région d'Odessa s'est enrichie en Co et Cd. La pollution des sédiments du plateau allait de « non polluée » à « très fortement polluée ». Depuis la fin du 20e siècle, la teneur en métaux lourds des sédiments du plateau est restée stable dans la région d'Odessa mais a augmenté dans la région du delta du Danube.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Sagasti, Alessandra. "The role of stress in determining community structure: Effects of hypoxia on an estuarine epifaunal community". W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539616839.

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Community models predict the effects of stress on community structure and processes. I tested the Menge and Sutherland 1987 model in an estuarine epifaunal community experiencing low oxygen stress, termed hypoxia. Epifauna, animals living on the surfaces of substrates, are ecologically important in many estuaries where hypoxia occurs, yet little is known about the effects of hypoxia on these communities. Epifauna formed dense communities in the York River, a tributary of the Chesapeake Bay, USA, despite frequent hypoxia. Abundance and species composition was similar in two areas of the river, even though the downstream study area often experienced lower oxygen concentrations during hypoxic episodes than the upstream study area. Many dominant species exposed to high and low oxygen in the laboratory had a median lethal time (LT50) in hypoxia greater than the duration of typical hypoxic episodes in the York River, suggesting that hypoxia may cause little mortality for many species in this system. Predation by a variety of taxa decreased during hypoxia in the laboratory, because many mobile predators had higher mortality than sessile prey, and because predation rates decreased. Peak recruitment of dominant taxa, and of total epifauna, in the York River occurred during neap tides in the downstream study area, coinciding with the lowest oxygen concentrations. In the laboratory, low oxygen decreased recruitment of dominant taxa, but some recruitment continued in hypoxia for most taxa, indicating that larvae of dominant epifauna are tolerant of hypoxia. Larval tolerance of hypoxia may allow communities to persist even though the recruitment season of many epifaunal species coincides with the peak season of hypoxia. These findings supported some predictions of the consumer stress model, but not all. as predicted, when stress increased, the importance of disturbance for determining community structure increased, while the importance of predation decreased. Unlike predictions, stress changed recruitment rates in the laboratory. There were few effects of stress on abundance and diversity, possibly because in this system hypoxia is mild, brief, and because the species in this community can tolerate stress, colonize disturbed areas quickly, and grow quickly enough to complete life-cycles between hypoxic episodes.

Più fonti

Libri sul tema "Hypoxie marine":

Diaz, R. J. Ecological and economic consequences of hypoxia: Topic 2, report for the integrated assessment on hypoxia in the Gulf of Mexico. Silver Spring, Md. (1315 East-West Highway, Room 9700, Silver Spring 20910): U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Sponsored Coastal Ocean Research--Coastal Ocean Program, 1999.

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Salas, Benjamin M. Hypoxia in the northern Gulf of Mexico. New York: Nova Science Publishers, 2011.

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National Science and Technology Council (U.S.). Committee on Environment and Natural Resources., a cura di. Integrated assessment of hypoxia in the northern Gulf of Mexico. [Washington, D.C.]: National Science and Technology Council, Committee on Environment and Natural Resources, 2000.

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United States. Congress. Senate. Committee on Environment and Public Works. Water quality in Lake Erie: Field hearing before the Committee on Environment and Public Works, United States Senate, One Hundred Seventh Congress, second session, on anoxia in the central basin of Lake Erie, and the impact of "dead zones" on the ecology of the Great Lakes region, August 5, 2002, Cleveland, OH. Washington: U.S. G.P.O., 2004.

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Renaud, Maurice L. Annotated bibliography on hypoxia and its effects on marine life, with emphasis on the Gulf of Mexico. Seattle, Wash.]: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 1985.

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Louisiana State University (Baton Rouge, La.). Coastal Studies Institute, Coastal Marine Institute (Baton Rouge, La.) e United States. Minerals Management Service. Gulf of Mexico OCS Region, a cura di. Effects of simultaneous exposure to petroleum hydrocarbons, hypoxia, and prior exposure on the tolerance and sublethal responses of marine animals: Blue crabs and killifish : final report. [New Orleans]: U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, 2002.

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Stickle, William B. Effects of simultaneous exposure to petroleum hydrocarbons, hypoxia, and prior exposure on the tolerance and sublethal responses of marine animals: Blue crabs and killifish : final report. New Orleans: US Department of the Interior, Minerals Management Service, 2002.

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H, Johnson Owen, Tully Michael J, New York (State). Legislature. Senate. Committee on Environmental Conservation. Subcommittee on the Long Island Marine District e New York (State). Legislature. Senate. Majority Task Force on Suburbs in Transition, a cura di. In the matter of a legislative briefing on the subject: hypoxia - its causes and solution: Room 227, Samuels Hall, U.S. Merchant Marine Academy, Kings Proint, New York, October 11, 1988, 10:00 a.m. [Albany, NY: Long Island Marine District Subcommittee, 1988.

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Riggs, Sharon R. The effect of exposure to environmental normoxia and hypoxia on photosynthetic rate and chlorophyll concentration in intertidal Zostera marina leaves. Mount Vernon, Wash: Padilla Bay National Estuarine Research Reserve, Shorelands and Coastal Zone Management Program, Washington State Dept. of Ecology, 1995.

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National, Research Council (U S. ). Committee on the Mississippi River and the Clean Water Act: Scientific Modeling and Technical Aspects of Nutrient Pollutant Load Allocation and Implementation. Nutrient control actions for improving water quality in the Mississippi River basin and northern Gulf of Mexico. Washington, D.C: National Academies Press, 2009.

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Capitoli di libri sul tema "Hypoxie marine":

Kamp, G. "Intracellular Reactions Controlling Environmental Anaerobiosis in the Marine Annelid Arenicola Marina, A Fresh Look at Old Pathways". In Surviving Hypoxia, 5–17. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9780367813048-4.

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Brush, Mark J., e Scott W. Nixon. "A Reduced Complexity, Hybrid Empirical-Mechanistic Model of Eutrophication and Hypoxia in Shallow Marine Ecosystems". In Modeling Coastal Hypoxia, 61–93. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-54571-4_4.

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Diaz, Robert J., e Rutger Rosenberg. "Overview of anthropogenically-induced hypoxic effects on marine benthic fauna". In Coastal and Estuarine Studies, 129–45. Washington, D. C.: American Geophysical Union, 2001. http://dx.doi.org/10.1029/ce058p0129.

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Guerrini, A., M. A. Colangelo e V. U. Ceccherelli. "Recolonization patterns of meiobenthic communities in brackish vegetated and unvegetated habitats after induced hypoxia/anoxia". In Recruitment, Colonization and Physical-Chemical Forcing in Marine Biological Systems, 73–87. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-2864-5_7.

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Craig, J. Kevin, Larry B. Crowder, Charlotte D. Gray, Carrie J. McDaniel, Tyrrell A. Kenwood e James G. Hanifen. "Ecological effects of hypoxia on fish, sea turtles, and marine mammals in the northwestern Gulf of Mexico". In Coastal and Estuarine Studies, 269–91. Washington, D. C.: American Geophysical Union, 2001. http://dx.doi.org/10.1029/ce058p0269.

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"Mitigating Impacts of Natural Hazards on Fishery Ecosystems". In Mitigating Impacts of Natural Hazards on Fishery Ecosystems, a cura di Wayne A. Palsson, Robert E. Pacunski, Tony R. Parra e Jim Beam. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874011.ch21.

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Abstract.—The impacts of hypoxia on fishes have been studied in shallow estuaries of the eastern coast of the United States and in Europe, but only recently has hypoxia received attention on the West Coast of North America. Hypoxia has had a dramatic impact on fish populations in southern Hood Canal, Washington, a long, narrow fjord characterized by weak flushing. We have used visual surveys while on scuba to track the abundance and depth distribution of rockfishes, lingcod Ophiodon elongatus, and other marine fishes at the Sund Rock Conservation Area in southern Hood Canal since 2001. By correlating ambient oxygen concentrations with fish abundance and by relating fish kills to oxygen concentrations, we are developing a model for predicting when fish will avoid or be killed by low oxygen events. Copper rockfish Sebastes caurinus avoid oxygen concentrations below 2 mg/L but can tolerate concentrations to 1 mg/L. Other marine fish species show similar responses, but smaller fish and species appear to be affected more than larger ones. Fish kill events are not consistent between years, affecting rockfish in one instance and lingcod in another. Differences in behavior and lethality during hypoxic conditions may relate to the magnitude and duration of exposure, temperature, past experience, and physiology. Recent and past fish kill events have resulted in long-term impacts reducing populations of rockfish and lingcod at Sund Rocks by one-third. Based on our results, continued efforts to minimize other population stressors are warranted.

Nor, Rizal Mohd, e Mikhail Nesterenko. "Unattended Sensors in Marine Environments". In Oceanography and Coastal Informatics, 396–419. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7308-1.ch018.

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This chapter discusses the use of unattended sensors and its use in marine environment. The authors present challenges of designing a marine sensor in harsh environments and a case study in implementing a marine sensor to study hypoxia. Hypoxia is a world-wide anthropogenic phenomenon related to pollution. The authors describe the construction of an inexpensive sensor buoy system, Oxybuoy, designed for long-term unattended oxygen sensor measurements. The technology is available to construct such sensor buoys. The authors showed a prototype based on commercial off-the shelf components: an embedded PC, an optical dissolved oxygen sensor, a temperature sensor, a Wi-Fi transmitter and a satellite transmitter. Its total cost is around $5,000 to construct, program and test a proof of concept of such sensor. The authors describe the buoy's architectural design and three experiments that the authors carried out to demonstrate its viability.

Kirchman, David L. "Dead Zones Discovered in Coastal Waters". In Dead Zones, 21–35. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197520376.003.0003.

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This chapter describes the discovery of coastal dead zones, such as the Gulf of Mexico and Chesapeake Bay in North America and the Baltic and Black Seas in Europe. Gene Turner sailed out of Pascagoula, Mississippi, in the spring of 1975, on the first of seven cruises that led to the discovery of the Gulf of Mexico dead zone. In the Chesapeake Bay, an unlikely environmentalist, Charles Officer, sounded the alarm in 1984. The biggest dead zone, however, is the Baltic Sea. Even as early as 1969, ecologists feared hypoxia was turning the Baltic into a “biological desert.” The northwest shelf of the Black Sea turned hypoxic in the 1970s, which killed bottom-dwelling fish like goby and flounder. Many coastal regions around the world have low oxygen waters that devastate marine life and habitats. The early studies emphasized one or two of three ingredients—sewage, fresh water, and plant nutrients—thought to be essential in creating a dead zone. This chapter and Chapter 3 discuss these ingredients before revealing which is most important.

Burge, Colleen A., e Paul K. Hershberger. "Climate change can drive marine diseases". In Marine Disease Ecology, 83–94. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198821632.003.0005.

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As an ultimate driver of marine ecosystem processes, climate change is expected to influence proximate disease drivers in marine systems. The observable effects of climate change, including changes in temperature, hypoxia, CO₂ accumulation, precipitation, and storm and cyclone frequencies and intensities, may directly act as proximate drivers of marine disease, especially in poikilotherms. These climate-driven changes are expected to result in the active and passive movement of pathogens and hosts into previously naïve geographical areas, thereby disrupting the long-evolved, stable host–pathogen relationships. Additionally, large-scale ecological changes stemming from climate change are expected to impact pathogen virulence and host susceptibilities. These real and anticipated changes present evolving challenges for resource managers who are charged with managing stochastic marine diseases in a constantly changing environment.

Diaz, R. J., R. J. Neubauer, L. C. Schaffner, L. Pihl e S. P. Baden. "Continuous monitoring of dissolved oxygen in an estuary experiencing periodic hypoxia and the effect of hypoxia on macrobenthos and fish". In Marine Coastal Eutrophication, 1055–68. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89990-3.50091-2.

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Atti di convegni sul tema "Hypoxie marine":

Essassi, Fatima Elzahra, e Yucheng Liu. "Engineering a Cost-Effective Solution for Measuring Sea Turtles’ Responses to Hypoxia". In ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-111634.

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Abstract This study aimed to design a case for an accelerometer, a pressure transducer, and a battery to be attached to sea turtles in order to determine their reactions in hypoxic environments. Hypoxia, caused by fertilizer runoff from the Mississippi River into the Gulf of Mexico, represents a significant challenge to the marine ecosystem in the waters. The case design was expected to be waterproof, buoyant, 3D printable, secure for all components, able to withstand pressures at a depth of 500 feet, and resistant to the corrosiveness of salt water, all while being cost-effective. The study resulted in the creation of a dome-shaped case manufactured using ABS plus. This case could be attached to a turtle’s shell using an epoxy adhesive and implemented a nitrile rubber O-ring to ensure waterproofness. In addition, stainless steel fasteners were used to protect it against saltwater corrosion. Despite meeting all the design requirements, the study made recommendations for a more failsafe design. This work provides a valuable contribution to the field of marine biology by offering a cost-effective and reliable solution for monitoring sea turtle responses to hypoxia in oxygen-deficient environments. The developed case meets all the requirements and can be a useful tool for ocean ecology research.

Zygadlowska, Olga, Wytze Lenstra, Niels van Helmond, Thomas Röckmann, Jessica Venetz, Anna Wallenius, Paula Dalcin Martins, Annelies Veraart, Mike Jetten e Caroline Slomp. "Methane dynamics in a seasonally hypoxic coastal marine basin". In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.7163.

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Chiba, Satoshi, Satoshi Chiba, Maki Oyagi, Maki Oyagi, Hideki Kokubu, Hideki Kokubu, Yoshinori Tanimura et al. "FIELD SURVEY FOR REFRACTORY ORGANIC MATTER QUANTITY IN THE MARINE SEDIMENT OF ISE BAY AND EVALUATION OF ITS EFFECT ON THE PERSISTENCY OF HYPOXIC WATER GENERATION". In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b944a57dc00.06450512.

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This study was performed to investigate the effect of the refractory organic matter (ROM) in the marine sediment on the lengthening of the large scale generation of the hypoxic water in Ise Bay. A field survey for collecting core samples of the sediment was conducted in 2015. The analysis with the data of sedimentation rate revealed many important features. A considerable amount of ROM deposited during the period of excess eutrophication in the past was found in the sediment. The total quantity of the degradable ROM (d-ROM) per unit seafloor area was from 71 to 231 mgC/cm2. The mean characteristic time of degradation of d-ROM was about 47 years. A pelagic ecosystem - marine sediment coupled model was employed and the long-term simulation from 1950 was carried out. The simulation results showed the total quantity of d-ROM reaches its maximum at the year around 2000 and there is about a 20 year delay from the peak time of the eutrophication. This feature caused the prolongation of the higher oxygen consumption as well as the higher nutrient release from the sediment in recent years. The increase of the hypoxic water area and the volume in 2010 due to the excess ROM was about 11% and 18%, respectively. These findings show the substantial effect of ROM in the marine sediment on the persistency of water pollution.

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Marquez, Jose, Justin Penn, Kyra N. Anderson, Murray Ian Duncan, Richard Stockey, Christopher P. Noll, Thomas Boag, Kemi Ashing-Giwa, Curtis Deutsch e Erik A. Sperling. "COMPARING THE HYPOXIA TOLERANCE AND TEMPERATURE SENSITIVITIES OF PALEOZOIC AND MODERN MARINE FAUNA". In GSA Connects 2023 Meeting in Pittsburgh, Pennsylvania. Geological Society of America, 2023. http://dx.doi.org/10.1130/abs/2023am-394731.

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Marquez, Jose Andres, Murray Ian Duncan, Murray Ian Duncan, Richard Stockey, Richard Stockey, Thomas Boag, Thomas Boag, Erik Sperling e Erik Sperling. "COMPARING THE HYPOXIA TOLERANCE AND TEMPERATURE SENSITIVITIES OF PALEOZOIC AND MODERN MARINE FAUNA". In GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-370636.

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Marquez, Jose. "COMPARING THE HYPOXIA TOLERANCE AND TEMPERATURE SENSITIVITIES OF PALEOZOIC AND MODERN MARINE FAUNA". In GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-383857.

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"Genes expression related to the effects of hypoxia in the marine mussel, Mytilus galloprovincialis". In Bioinformatics of Genome Regulation and Structure/ Systems Biology. institute of cytology and genetics siberian branch of the russian academy of science, Novosibirsk State University, 2020. http://dx.doi.org/10.18699/bgrs/sb-2020-083.

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Miller, Jonathon D., Brett J. Warren e Luc G. Chabot. "Microbiologically Influenced Corrosion of Gulf of Mexico Mooring Chain at 6,000 Feet Depths". In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-84067.

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Abstract (sommario):

During a post-installation inspection of a polyester and chain mooring system in water depths of approximately 6,000 ft, evidence of microbiologically influenced corrosion (MIC) was found in the form of rust tubercles known as rusticles. These porous concretions commonly form on submerged steel shipwrecks and provide evidence that subsea corrosion occurs in a hypoxic environment. Iron and sulfate-reducing bacteria cause corrosion in marine environments. This paper will discuss one form of MIC found on submerged steel structures, analyze the ambient conditions required for MIC to occur, and compare rusticles found during the mooring inspection to those found on other subsea shipwrecks such as the RMS Titanic. An analysis of the type of iron used in mooring chains and the rate of rusticle formation will be presented. Possible remedies to prevent rusticle growth on mooring chains will be summarized.

Bach, Duc-Hiep, Woong Sub Byun, Seong-Hwan Kim, Ji-Young Hong, Hyen Joo Park, Dong-Chan Oh e Sang Kook Lee. "Abstract 4070: Salternamide A, a marine natural product, suppresses hypoxia-induced accumulation of HIF-1α and induces apoptosis in human colorectal cancer cells". In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-4070.

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