Sediment data for Georgia streams, water years 1958-82

1985 ◽  
Author(s):  
Howard Perlman
Keyword(s):  
Sediment Data

Multifractal analysis of geochemical stream sediment data in Bange region, northern Tibet

2015 ◽  
Vol 26 (3) ◽  
pp. 317-327 ◽  
Author(s):  
Xianzhong Ke ◽  
Shuyun Xie ◽  
Youye Zheng ◽  
Salah Fadlallah Awadelseid ◽  
Shunbao Gao ◽  
...  
Keyword(s):  
Multifractal Analysis ◽  
Stream Sediment ◽  
Northern Tibet ◽  
Sediment Data

scholarly journals Data heterogeneity and oldness, two difficulties to overcome for the world seabed sediment mapping

2021 ◽  
Vol 4 ◽  
pp. 1-7
Author(s):  
Thierry Garlan ◽  
Isabelle Gabelotaud ◽  
Elodie Marchès ◽  
Edith Le Borgne ◽  
Sylvain Lucas
Keyword(s):  
Global Scale ◽  
Single Product ◽  
Seabed Sediment ◽  
Bathymetric Data ◽  
The World ◽  
Data Heterogeneity ◽  
Sediment Data ◽  
The University ◽  
Seabed Sediments

Abstract. A global seabed sediment map has been developed since 1995 to provide a necessary tool for different needs. This project is not completely original since it had already been done in 1912 when the French hydrographic Office and the University of Nancy produced sedimentary maps of the European and North American coasts. Seabed sediments is one of the last geographical domains which can’t benefit of satellite data. Without this contribution, sediment maps need to use very old data mixed with the new ones to be able to reach the goal of a global map. In general, sediment maps are made with the latest available techniques and are replaced after a few decades, thus generating new cartographic works as if all the previous efforts had become useless. Such approach underestimates the quality of past works and prevents to have maps covering large areas. The present work suggests to standardize all kind of sedimentary data from different periods and from very different acquisition systems and integrate them into a single product. This process has already been done for bathymetric data of marine charts, we discuss in this article of the application of this method at a global scale for sediment data.

scholarly journals Technical note: A time-integrated sediment trap to sample diatoms for hydrological tracing

2020 ◽  
Vol 24 (10) ◽  
pp. 4709-4725
Author(s):  
Jasper Foets ◽  
Carlos E. Wetzel ◽  
Núria Martínez-Carreras ◽  
Adriaan J. Teuling ◽  
Jean-François Iffly ◽  
...  
Keyword(s):  
Water Quality Assessment ◽  
Technical Note ◽  
Sampling Effort ◽  
Terrestrial Environment ◽  
The Third ◽  
Run Off ◽  
Analysis Of Similarity ◽  
Sediment Data ◽  
Almost All ◽  
Diatom Community Composition

Abstract. Diatoms, microscopic single-celled algae, are present in almost all habitats containing water (e.g. streams, lakes, soil and rocks). In the terrestrial environment, their diversified species distributions are mainly controlled by physiographical factors and anthropic disturbances which makes them useful tracers in catchment hydrology. In their use as a tracer, diatoms are generally sampled in streams by means of an automated sampling method; as a result, many samples must be collected to cover a whole storm run-off event. As diatom analysis is labour-intensive, a trade-off has to be made between the number of sites and the number of samples per site. In an attempt to reduce this sampling effort, we explored the potential for the Phillips sampler, a time-integrated mass-flux sampler, to provide a representative sample of the diatom assemblage of a whole storm run-off event. We addressed this by comparing the diatom community composition of the Phillips sampler to the composite community collected by automatic samplers for three events. Non-metric multidimensional scaling (NMDS) showed that, based on the species composition, (1) all three events could be separated from each other, (2) the Phillips sampler was able to sample representative communities for two events and (3) significantly different communities were only collected for the third event. These observations were generally confirmed by analysis of similarity (ANOSIM), permutational multivariate analysis of variance (PERMANOVA), and the comparison of species relative abundances and community-derived indices. However, sediment data from the third event, which was sampled with automatic samplers, showed a large amount of noise; therefore, we could not verify if the Phillips sampler sampled representative communities or not. Nevertheless, we believe that this sampler could not only be applied in hydrological tracing using terrestrial diatoms, but it might also be a useful tool in water quality assessment.

Subsurface sediment profiles below Point Pelee: indicators of postglacial evolution in western Lake Erie

1998 ◽  
Vol 35 (1) ◽  
pp. 88-99
Author(s):  
John P Coakley ◽  
Allan S Crowe ◽  
Patrice A Huddart
Keyword(s):  
Lake Levels ◽  
Dune Sand ◽  
Radiocarbon Dates ◽  
Subsurface Sediment ◽  
Fine Grained ◽  
Western Lake ◽  
Planar Wave ◽  
Point Pelee ◽  
Sediment Data ◽  
Point Pelee National Park

An extensive drilling program, undertaken along the western barrier bar at Point Pelee National Park, Ontario, Canada, yielded considerable subsurface sediment data relevant to the nature and lateral geometry of sedimentary units below the Point Pelee foreland. Four major sedimentary units were identified: a basal clay-rich till, a fine-grained glaciolacustrine sand, a medium-grained sand unit (subdivided into a poorly sorted shoreface sand and an aeolian (dune) sand derived from the shoreface sand), and an organic marsh (gyttja) deposit. The present study confirms the existence of a planar, wave-eroded till surface below the southern portion of Point Pelee at an elevation of approximately 164 m asl. Following this low-water period in the basin, lake levels rose abruptly to an elevation several metres above 172 m asl. This resulted in erosion of the upper part of the glaciolacustrine sand during a later period of stable higher lake levels, perhaps coinciding with the Nipissing flood event (about 4000 BP). This resulted in a planar surface at approximately 169.5 m asl. Several radiocarbon dates on basal gyttja from the marsh (averaging 3200 BP) reflect a subsequent drop in levels to about 2-3 m below present levels. Though undated, the initiation of shoreface and dune sand deposition is roughly coeval with the basal marsh deposits.

An attempt to understand δ13C cycles with a simple conceptual model.

2021 ◽  
Author(s):  
Gaelle Leloup ◽  
Didier Paillard
Keyword(s):  
Organic Matter ◽  
Carbon Cycle ◽  
Conceptual Model ◽  
Carbon Isotope ◽  
Time Scale ◽  
Marine Biology ◽  
Climate Modelling ◽  
Orbital Eccentricity ◽  
Sediment Data ◽  
Geomagnetic Polarity

<div> <div> <p>A correct understanding of the human perturbation on the carbon cycle is a fundamental prerequisite of future climate modelling on large timescales.</p> <p>However, « classical » carbon cycle theories barely take into account the « organic » part of the carbon cycle and are not able to reproduce past δ<sup>13</sup>C data.</p> <p>Analysis of sediment data reveals the presence of cycles in the δ<sup>13</sup>C record. A 400 kyr cycle has been observed at several time periods, from the Eocene to present [1-4]. Moreover, longer cycles have been observed : 2.4, 4.6 and 9 Myr [5-8]. The 9 Myr cycle is present since the start of the Mesozoic. These periodicities seem linked to eccentricity periods.</p> <p>By forcing astronomically the (net) organic matter burial in a carbon cycle conceptual model, Paillard [9] reproduced 400 kyr and 2.4 Myr cycles in δ<sup>13</sup>C.</p> <p>The net organic matter burial has a key role on δ<sup>13</sup>C, as terrestrial and marine biology preferentially use <sup>12</sup>C during photosynthesis. Therefore if the burial of (<sup>12</sup>C rich) organic matter is relatively more important, the δ<sup>13</sup>C of the superficial system will decrease, and inversely.</p> <p>However, this conceptual model was not able to explain longer term cycles at 4.6 and 9 Myr.</p> <p>Here, we develop a new conceptual model based on Paillard [9], which includes the role of oxygen. Indeed, oxygen also influences the organic matter burial.</p> <p>With this new conceptual model coupling carbon and oxygen cycle, it is possible to obtain 400 kyr, 2.4 Myr, but also longer cycles.</p> <p> </p> <p>References :</p> <p>[1] Sexton et al, 2011, Eocene global warming events driven by ventilation of oceanic dissolved organic carbon</p> <p>[2] Pälike et al, 2006 The Heartbeat of the Oligocene Climate System</p> <p>[3] Billups et al, 2004 Astronomic calibration of the late Oligocene through early Miocene geomagnetic polarity time scale</p> <p>[4]Wang et al, 2010, Obscuring of long eccentricity cyclicity in Pleistocene oceanic carbon isotope records</p> <p>[5] Boulila et al, 2012, A ~9 myr cycle in Cenozoic δ13C record and long-term orbital eccentricity modulation: Is there a link?</p> <p>[6] Ikeda et al, 2014, 70 million year astronomical time scale for the deep-sea bedded chert sequence (Inuyama, Japan): Implications for Triassic–Jurassic geochronology.</p> <p>[7] Martinez et al, 2015, Orbital pacing of carbon fluxes by a ∼9-My eccentricity cycle during the Mesozoic</p> <p>[8] Sprovieri M, et al. (2013) Late Cretaceous orbitally-paced carbon isotope stratigraphy from the Bottaccione Gorge (Italy).</p> <p>[9] Paillard, 2017, The Plio-Pleistocene climatic evolution as a consequence of orbital forcing on the carbon cycle.</p> </div> </div>

Collaborative Seabed-Habitat Mapping

2015 ◽  
pp. 154-176 ◽  
Author(s):  
Sytze van Heteren ◽  
Vera Van Lancker
Keyword(s):  
Habitat Heterogeneity ◽  
Environmental Science ◽  
End Users ◽  
Habitat Mapping ◽  
Small Scale ◽  
Science And Policy ◽  
Research Institutes ◽  
Point Data ◽  
Sediment Data ◽  
Flexible Querying

This chapter discusses the uncertainties associated with sediment data, which are a commonly neglected obstacle in collaborative seabed-habitat mapping, complicating harmonization. Standardization of these data, although an important prerequisite in the harmonization of surrogate-based habitat maps, is not enough to achieve full map uniformity. Through time and between research institutes, data have been acquired, described, analyzed, and classified using a range of methods and protocols. The effects of differing error margins and indicative meanings remain hidden for most end users in environmental science and policy. The interpolation required to generate full-coverage data products from sedimentological point data creates additional uncertainty. Finally, small-scale habitat heterogeneity not captured by even the densest sampling places limits on the usability of sediment-based surrogates as well. Despite these limitations, there is much room for improvement when it comes to using surrogates in habitat mapping. Multiple visualizations generated from merged digital sediment datasets with flexible querying protocols are especially promising.

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