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Littérature scientifique sur le sujet « Bioturbation indice »
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Articles de revues sur le sujet "Bioturbation indice"
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LAING, BRITTANY A., LUIS A. BUATOIS, M. GABRIELA MÁNGANO, NICHOLAS J. MINTER, LUKE C. STROTZ, GUY M. NARBONNE et GLENN A. BROCK. « BIOTURBATORS AS ECOSYSTEM ENGINEERS : ASSESSING CURRENT MODELS ». PALAIOS 37, no 12 (29 décembre 2022) : 718–30. http://dx.doi.org/10.2110/palo.2022.012.
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ABSTRACT Bioturbating organisms can dramatically alter the physical, chemical, and hydrological properties of the sediment and promote or hinder microbial growth. They are a classic example of “ecosystem engineers” as they alter the availability of resources to other species. Multiple evolutionary hypotheses evoke bioturbation as a possible driver for historical ecological change. To test these hypotheses, researchers need reliable and reproducible methods for estimating the impact of bioturbation in ancient environments. Early efforts to record and compare this impact through geologic time focused on the degree of bioturbation (e.g., bioturbation indices), the depth of bioturbation (e.g., bioturbation depth), or the structure of the infaunal community (e.g., tiering, ecospace utilization). Models which combine several parameters (e.g., functional groups, tier, motility, sediment interaction style) have been proposed and applied across the geological timescale in recent years. Here, we review all models that characterize the impact of bioturbators on the sedimentary environment (i.e., ‘ecosystem engineering'), in both modern and fossil sediments, and propose several questions. What are the assumptions of each approach? Are the current models appropriate for the metrics they wish to measure? Are they robust and reproducible? Our review highlights the nature of the sedimentary environment as an important parameter when characterizing ecosystem engineering intensity and outlines considerations for a best-practice model to measure the impact of bioturbation in geological datasets.
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Ayranci, Korhan, Isa E. Yildirim, Umair bin Waheed et James A. MacEachern. « Deep Learning Applications in Geosciences : Insights into Ichnological Analysis ». Applied Sciences 11, no 16 (22 août 2021) : 7736. http://dx.doi.org/10.3390/app11167736.
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Ichnological analysis, particularly assessing bioturbation index, provides critical parameters for characterizing many oil and gas reservoirs. It provides information on reservoir quality, paleodepositional conditions, redox conditions, and more. However, accurately characterizing ichnological characteristics requires long hours of training and practice, and many marine or marginal marine reservoirs require these specialized expertise. This adds more load to geoscientists and may cause distraction, errors, and bias, particularly when continuously logging long sedimentary successions. In order to alleviate this issue, we propose an automated technique to determine the bioturbation index in cores and outcrops by harnessing the capabilities of deep convolutional neural networks (DCNNs) as image classifiers. In order to find a fast and robust solution, we utilize ideas from deep learning. We compiled and labeled a large data set (1303 images) composed of images spanning the full range (BI 0–6) of bioturbation indices. We divided these images into groups based on their bioturbation indices in order to prepare training data for the DCNN. Finally, we analyzed the trained DCNN model on images and obtained high classification accuracies. This is a pioneering work in the field of ichnological analysis, as the current practice is to perform classification tasks manually by experts in the field.
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Vesal, Seyed Ehsan, Federica Nasi, Rocco Auriemma et Paola Del Negro. « Effects of Organic Enrichment on Bioturbation Attributes : How Does the Macrofauna Community Respond in Two Different Sedimentary Impacted Areas ? » Diversity 15, no 3 (17 mars 2023) : 449. http://dx.doi.org/10.3390/d15030449.
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We assessed the influence of different organic matter (OM) inputs associated with terrigenous/freshwater allochthonous and sewage derive on bioturbation and irrigation potential community indices (BPc and IPc) of the soft-bottom macrofauna community. The macrofauna was sampled from two different sedimentary impacted areas, in front of the Po River Delta (northern Adriatic Sea) and sewage discharge diffusion zone (Gulf of Trieste). The highest values of BPc and IPc were observed at the northward sampling stations of the prodelta and the stations 25 m distance in front of the main sewage outfall. Species richness showed high values in the prodelta likely due to the OM positive effect from the delta, and it increased with increasing distance from the pipeline due to the effect of OM from the sewage discharge. The bioturbation indices differed due to the presence of surface deposit feeders and the injection depth (from 2 to 5 cm) with limited movement at the station located northwards in the prodelta and 25 m distance in the diffusion zone. We infer that the difference in bioturbation indices was likely due to the effects of grain-size composition and the degree of organic enrichment in both study areas.
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Miernik, Natalia Anna, Urszula Janas et Halina Kendzierska. « Role of Macrofaunal Communities in the Vistula River Plume, the Baltic Sea—Bioturbation and Bioirrigation Potential ». Biology 12, no 2 (18 janvier 2023) : 147. http://dx.doi.org/10.3390/biology12020147.
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Macrozoobenthos plays a key role in the transformation of inputs from rivers to the sea, such as nutrients, organic matter, or pollutants, and influences biogeochemical processes in the sediments through bioturbation and bioirrigation activity. The purpose of our study was to determine the structure of benthic communities, their bioturbation (BPC) and bioirrigation potential (IPC), and the vertical distribution of macrofauna in the Gulf of Gdańsk. The study revealed changes in the structure of benthic communities and, consequently, in the bioturbation and bioirrigation potential in the study area. Despite the presence of diverse and rich communities in the coastal zone, BPC and IPC values, although high, were formed by a few species. Both indices were formed mainly by the clam Macoma balthica and polychaetes, although the proportion of polychaetes in IPC was higher than in BPC. In the deepest zones, the communities became poorer until they eventually disappeared, along with all macrofaunal functions. Both indices changed similarly with distance from the Vistula River mouth, and there was a very strong correlation between them. We also demonstrated that the highest diversity of the macrofauna was observed in the upper first cm of the sediment, but the highest biomass was observed in deeper layers—at a depth of up to 6 cm, and single individuals occurred even below 10 cm.
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Honeycutt, Chris Ebey, et Roy Plotnick. « Image analysis techniques and gray-level co-occurrence matrices (GLCM) for calculating bioturbation indices and characterizing biogenic sedimentary structures ». Computers & ; Geosciences 34, no 11 (novembre 2008) : 1461–72. http://dx.doi.org/10.1016/j.cageo.2008.01.006.
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Culhane, Fiona E., Robert A. Briers, Paul Tett et Teresa F. Fernandes. « Response of a marine benthic invertebrate community and biotic indices to organic enrichment from sewage disposal ». Journal of the Marine Biological Association of the United Kingdom 99, no 8 (28 octobre 2019) : 1721–34. http://dx.doi.org/10.1017/s0025315419000857.
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AbstractNutrient enrichment is a significant cause of ecosystem change in coastal habitats worldwide. This study focuses on the change in a benthic macroinvertebrate community and environmental quality as assessed through different biotic indices following the construction of a sewage outfall pipe in the west of Scotland, from first implementation to seven years after operation of the pipe. Benthic macroinvertebrates are an important part of marine ecosystems because they mediate ecosystem processes and functions, are a key part of food webs and they provide many ecosystem services. Results indicated a clear change in benthic communities over time with an increase in species richness and changes to benthic community composition (specifically feeding type, bioturbation mode and ecological group) towards those indicative of organic enrichment. No clear spatial zonation was observed because organic carbon content increased over the entire area. According to a suite of benthic indices calculated, some negative changes were detectable following the start of sewage disposal, but largely negative community changes, and a change from ‘good’ to ‘moderate’ quality, only occurred seven years after implementation. The increase in species richness in response to increasing disturbance reduced the utility of a multi-metric index, the Infaunal Quality Index, which, instead of amplifying the signal of negative impact, dampened it. We suggest that any change in communities, regardless of direction, should be heeded, and species richness is a particularly sensitive and early warning indicator for this, but a suite of approaches is required to understand benthic community changes.
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Mochizuki, Takafumi, Tatsuo Oji, Yuanlong Zhao, Jin Peng, Xinglian Yang et Sersmaa Gonchigdorj. « Diachronous Increase in Early Cambrian Ichnofossil Size and Benthic Faunal Activity in Different Climatic Regions ». Journal of Paleontology 88, no 2 (mars 2014) : 331–38. http://dx.doi.org/10.1666/13-056.
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In order to clarify the pattern of diversification and processes of biological activity during the Cambrian radiation, ichnofossils were comparatively studied in the early Cambrian sections of Newfoundland, South China and western Mongolia. Special attention was paid to size distributions of the most common ichnogenus,Planolites, and the densities of all the observed ichnofossils that preserve animal activity as expressed by bedding plane bioturbation indices (BPBI).From the Fortune Head section in Newfoundland, a clear size increase in the ichnogenusPlanolitesis confirmed from theTreptichnus pedumZone to the overlyingRusophycus avalonensisZone. The BPBI also shows much stronger biological activity in theR. avalonensisZone than in theT. pedumZone. In Meishucun, South China and Gobi-Altai, Mongolia, however, a variety ofPlanolitessizes had already appeared in theT. pedumZone, and the BPBI's on some bedding surfaces of theT. pedumZone are already comparable to those in theR. avalonensisZone in Newfoundland. In the earliest Cambrian, diversification and increase in the biological activity of the benthic fauna were diachronous in the wide geographic scale, starting earlier at lower latitudes (South China and western Mongolia) than at higher latitudes (Newfoundland), reflecting differences in the onset of Cambrian benthic animal activity under different climatic conditions.
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Menta, Cristina, et Sara Remelli. « Soil Health and Arthropods : From Complex System to Worthwhile Investigation ». Insects 11, no 1 (16 janvier 2020) : 54. http://dx.doi.org/10.3390/insects11010054.
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The dramatic increase in soil degradation in the last few decades has led to the need to identify methods to define not only soil quality but also, in a holistic approach, soil health. In the past twenty years, indices based on living communities have been proposed alongside the already proven physical-chemical methods. Among them, some soil invertebrates have been included in monitoring programs as bioindicators of soil quality. Being an important portion of soil fauna, soil arthropods are involved in many soil processes such as organic matter decomposition and translocation, nutrient cycling, microflora activity regulation and bioturbation. Many studies have reported the use of soil arthropods to define soil quality; among taxa, some have been explored more in depth, typically Acari and Collembola, while generally less abundant groups, such as Palpigradi or Embioptera, have not been investigated much. This paper aims to evaluate and compare the use of different soil microarthropod taxa in soil degradation/quality studies to highlight which groups are the most reported for soil monitoring and which are the most sensitive to soil degradation. We have decided not to include the two most present and abundant taxa, Acari and Collembola, in this paper in consideration of the vast amount of existing literature and focus the discussion on the other microarthropod groups. We reported some studies for each taxon highlighting the use of the group as soil quality indicator. A brief section reporting some indices based on soil microarthropods is proposed at the end of this specific discussion. This paper can be considered as a reference point in the use of soil arthropods to estimate soil quality and health.
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Gogina, Mayya, Judith Rahel Renz, Stefan Forster et Michael L. Zettler. « Benthic Macrofauna Community Bioirrigation Potential (BIPc) : Regional Map and Utility Validation for the South-Western Baltic Sea ». Biology 11, no 7 (20 juillet 2022) : 1085. http://dx.doi.org/10.3390/biology11071085.
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Benthic community bioirrigation potential (BIPc), an index developed to quantify the anticipated capacity of macrofauna to influence the solute exchange at the sediment–water interface, was calculated for the south-western Baltic Sea. This index can be regarded as an effect trait that is useful for predicting ecosystem processes impacted by animal burrow ventilation. The special feature, and presumably an advantage, of BIPc, compared to alternative recently developed benthic macrofauna-based bioirrigation indices, lies in its ability to distinguish the taxa-specific score values between diffusion- and advection-dominated sediment systems. The usefulness of the BIPc index was compared against the estimates of the well-established community bioturbation potential index (BPc). The BIPc index displayed a moderately but significantly stronger correlation with estimates of irrigation rates derived from tracer experiments. Using a random forest machine learning approach and a number of available relevant environmental predictor layers, we have modelled and mapped the spatial differences in this ecosystem functioning expression. The key species contributing to bioirrigation potential in the study area were identified. The interannual variation in BIPc was assessed on a small exemplary dataset. The scores required to calculate the index, that were assigned to 120 taxa dominating abundance and biomass in the region, are provided for reuse. The utility, temporal variability and uncertainty of the distribution estimate are discussed.
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Schobben, Martin, Sebastiaan van de Velde, Jana Gliwa, Lucyna Leda, Dieter Korn, Ulrich Struck, Clemens Vinzenz Ullmann et al. « Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation ». Climate of the Past 13, no 11 (22 novembre 2017) : 1635–59. http://dx.doi.org/10.5194/cp-13-1635-2017.
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Abstract. Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian–Triassic boundary in the marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data, we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ13C variability, which is reproducible for the two studied regions. We suggest that (sub-)sea-floor microbial communities and their control on calcite nucleation and ambient porewater dissolved inorganic carbon δ13C pose a viable mechanism to induce bulk-rock δ13C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization and linked carbon isotope alteration can be controlled by organic matter supply and subsequent microbial remineralization. A major biotic decline among Late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation. Combined with low marine sulfate, this resulted in varying degrees of carbon isotope overprinting. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to 1 out of 10 samples, is sufficient to induce the observed signal of carbon isotope variability. These findings put constraints on the application of Permian–Triassic carbon isotope chemostratigraphy based on whole-rock samples, which appears less refined than classical biozonation dating schemes. On the other hand, this signal of increased carbon isotope variability concurrent with the largest mass extinction of the Phanerozoic may provide information about local carbon cycling mediated by spatially heterogeneous (sub-)sea-floor microbial communities under suppressed bioturbation.
Actes de conférences sur le sujet "Bioturbation indice"
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Shimomura, Takahiro, et Motoyoshi Yamanaka. « Sedimentary Characters and Flow Transitions of Reworked Carbonates : A Case Study of Cenomanian-Turonian Reworked Sediments in the Eastern Abu Dhabi, UAE ». Dans ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211637-ms.
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Abstract Reworked carbonate caused by the major erosional event of the "Turonian Unconformity" is considered to be distributed around the eastern part of Abu Dhabi, UAE. During 2021-2022, new wells were drilled in a prospective area where the reworked carbonate was deposited. By using the new wells data (wireline logs and cores) and pre-existing wells data, we considered lateral changes in sedimentary character and flow transitions of the reworked carbonate. We conducted a well-well correlation, based on the wireline logs (GR, Neutron, Density, Resistivity and Sonic) of a total of 5 wells which were drilled in the prospective area. To understand the spaciotemporal changes of the reworked carbonate facies and properties, we conducted core observation and description, and routine core analysis (porosity and permeability) for the new wells. In addition, based on the distribution and flow direction of this reworked deposit, we considered the changes of flow regime towards the flow direction. The result of the well-well correlation and seismic interpretation suggests that the wells penetrated the same reworked carbonate body. We can recognize the variety of grain size, sorting, sedimentary structure, and a degree of the bioturbation between the wells: poorly sorted coarse-grained to pebbly carbonate is dominant around the depositional up-dip side, and sharp based well-sorted grainstone with sedimentary structures (grading and lamination) is dominant around the depositional down-dip side, with bioturbation being more intense especially at the upper part of these grading beds. These sedimentary characters suggest that the flow regime changed towards the flow direction: dense flow at the depositional up-dip side and dilute flow at the down-dip side. In addition, several grading beds in the same indicate that the flow repeated several times. Routine core analysis and log calculation (porosity and permeability) results suggest that the sediments in a middle body of the reworked sediments has better reservoir properties. There is remaining exploration potential for this new play concept (reworked carbonate reservoir) around Abu Dhabi. In this time, we drilled new wells to confirm this new play concept, and we suppose that the knowledge of this study may have a big impact to the future exploration.
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Meng, Xiangmei, Yonggang Jia, Hongxian Shan et Jingtai Song. « Tidal Flat Erosional Features of the Modern Yellow River Delta ». Dans ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79209.
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In July and October of 2008, selected physical-mechanical sediment properties were measured at 20 tidal flat experiment stations of 8 regions along the seashore of the modern Yellow River delta. At the same time, the environmental characteristics were observed. Seabed properties were compared with measurements of sediment erodibility made at the same stations to gain insight into the bioturbation and physical-mechanical sediment properties’ controls on sediment erodibility. Results indicate that crabs obviously alter the surface roughness of seabed, which makes the sediment more easily eroded than the neighboring area without crabs. Sediment erodibility along the seashore of the modern Yellow River delta varies in different stations. The critical erosion shear stress varies between 0.088 Pa and 0.254 Pa for all measurements. The factors influencing sediment erodibility are complicated. No clear relationship was found between distinct physical-mechanical sediment properties parameters and the critical erosion threshold except that there’s a positive correlation between shear strength and critical erosion shear stress. Further studies are needed to more accurately resolve the relationship between erodibility and sediment properties.