Estimating marine sediment properties in a temporally varying water column environment

2010 ◽  
Author(s):  
Yong-Min Jiang ◽  
N. Ross Chapman ◽  
Jeffrey Simmen ◽  
Ellen S. Livingston ◽  
Ji-Xun Zhou ◽  
...  
Keyword(s):  
Water Column ◽  
Marine Sediment ◽  
Sediment Properties

Improving the Dewatering of Marine Sediment Using a Combination of Geo-Textile and Electrokinetic Treatment

2017 ◽  
Author(s):  
Silja Kostia ◽  
Janika Tuomi ◽  
Martin Romantschuk
Keyword(s):  
Water Column ◽  
Direct Current ◽  
Marine Sediment ◽  
Clay Content ◽  
Water Layer ◽  
Control Treatment ◽  
Dredged Material ◽  
Dredged Sediment ◽  
Electric Treatment ◽  
Electro Osmosis

The purpose of this study was to test whether electro-osmosis can be used to increase the effectiveness of dewatering of dredged sediment being drained in geo- textile tubes. The marine sediment used in the study had a high proportion of clay known to be problematic in geo-tube treatment. The laboratory set-ups were performed using sediment-filled sacks (approximately 5-7 liters / sack) sewn from geo-textile (TenCate Geotube® GT500), and plastic columns (approximately 1.6 liters / column) closed at the bottom with geo-textile, both supplied with electrodes for applying direct current. In the sack set-ups, a seven-hour electric treatment led to the same result as the 72-hour control treatment. The volume of the sediment decreased in column set-ups by 32 % due to electric treatment while only a 14 % decrease was obtained in the controls after 189 hours. The water layer on top of the sediment treated with electro-osmosis decreased by up to one-fifth, as compared to the control columns. We can conclude that electro-osmosis is an effective approach to boost the dewatering of the dredged sediment treated in geo-textile tubes. When draining sediment with a high clay content, electric treatment can prevent the formation of a water column on top of the sediment. This in turn accelerates dewatering of the dredged material.

Density-dependent effects of bioturbation by the clam, Scrobicularia plana, on the erodibility of estuarine sediments

2009 ◽  
Vol 60 (7) ◽  
pp. 737 ◽  
Author(s):  
Claudia Soares ◽  
Paula Sobral
Keyword(s):  
Water Column ◽  
Chlorophyll A ◽  
Extracellular Polymeric Substance ◽  
Feeding Behaviour ◽  
Estuarine Sediments ◽  
Tagus Estuary ◽  
Benthic Organisms ◽  
Sediment Properties ◽  
Density Dependent ◽  
Scrobicularia Plana

Benthic organisms are known to modify sediment properties and influence the flux of materials to the water column. In this study, the density-dependent effects of bioturbation by the estuarine clam, Scrobicularia plana, on the biogeochemical properties and erodibility of the sediment were assessed using laboratory annular flumes. Sediments with different mud contents (~98% and 90%) were collected undisturbed from two different sites of the Tagus estuary. S. plana were added to the sediment at increasing densities (0, 57, 115 and 229 ind m–2) and left to bioturbate the sediment before the experimental erosion runs. All erosion runs were carried out following a stepwise increase of current velocities (U) up to 0.25 m s–1. Sediment chlorophyll a, pheopigments and extracellular polymeric substance fractions were measured at the time of sampling in the field and in the end of the erosion runs. Increasing densities of S. plana in the muddier sediment raised eroded mass, while the sediment with less mud behaved as non-cohesive and registered a decrease in eroded mass possibly due to a switch in the feeding behaviour of S. plana.

scholarly journals Forecasting Marine Sediment Properties with Geospatial Machine Learning.

2021 ◽  
Author(s):  
Jennifer Frederick ◽  
William Eymold ◽  
Michael Nole ◽  
Benjamin Phrampus ◽  
Taylor Lee ◽  
...  
Keyword(s):  
Machine Learning ◽  
Marine Sediment ◽  
Sediment Properties

Methane oxidation processes in sediment of the Laptev and East Siberian Seas indicated from microbial lipids and carbon isotope composition

2021 ◽  
Author(s):  
Weichao Wu ◽  
Henry Holmstrand ◽  
Birgit Wild ◽  
Natalia Shakhova ◽  
Denis Kosmach ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arctic Ocean ◽  
Water Column ◽  
Marine Sediment ◽  
The Arctic ◽  
Laptev Sea ◽  
Microbial Lipids ◽  
East Siberian Sea ◽  
Siberian Arctic ◽  
The Laptev Sea

<p>The East Siberian Arctic Shelf is an integrated coastal sea system with complex biogeochemical processes influenced by underlying subsea permafrost, hydrates and thermogenic compartments. Methane is released from the marine sediments to the water column, which serves as an interphase between the lithosphere and the atmosphere. Before escaping into water column and atmosphere, methane has potentially experienced extensive aerobic and anaerobic oxidation by microbes in the marine sediment. In particular, the aerobic process is assumed to be dominant in the surface oxic/suboxic marine sediment (upper 1cm) after anaerobic processes in deeper zones. However, these processes are insufficiently understood in sediments of the Arctic Ocean. To probe these, we investigated the microbial lipids and their stable carbon composition in surface marine sediment (upper 1 cm) from two active methane seep areas in the Laptev Sea and the East Siberian Sea.</p><p>The microbial fatty acids (C12 to C18 fatty acids) were relatively enriched in <sup>13</sup>C (δ<sup>13</sup>C -18.8 to -31.2‰) compared to that of dissolved CH<sub>4</sub> in nearby bottom water (-54.6 to -29.7‰). This contrasts to previous reports of strongly depleted δ<sup>13</sup>C signals in microbial lipids (e.g., -100‰) at active marine mid-ocean ridges and mud volcanoes, from quite different ocean areas. The absence of a depleted δ<sup>13</sup>C signal in these general microbial biomarkers suggest that these reflect substrates other than methane such as other parts of the sediment organic matter, indicated by the stronger correlation of δ<sup>13</sup>C between fatty acids and bulk organic carbon than that between fatty acid and CH<sub>4</sub>. However, the putatively more specific biomarkers for aerobic methanotrophic bacteria (mono-unsaturated C16 and C18 fatty acids) show a distinct pattern in the Laptev Sea and East Siberian Sea: C16:1 and C18:1 were enriched in <sup>13</sup>C (up to 4.5 ‰) relative to their saturated analogs in the Laptev Sea; whereas, C18:1 was depleted in <sup>13</sup>C (up to 4.5 ‰) compared to C18 in the East Siberian Sea. This could be because the relative populations of Type I and II methanotrophs were different in the two areas with different carbon assimilation pathways. Our results cannot exclude a slowly active aerobic methanotrophs at methane seeps in the East Siberian Arctic Ocean and thus call for more information from molecular microbiology.</p>

Spatial Distribution of Total 210Pb in the Marine Sediment of Peninsular Malaysia: Radioactivity Level Variations in The Sunda Shelf Seas

2021 ◽  
Author(s):  
Nur Ashikin Zaini ◽  
Mohamad Arif Che Abd Rahim ◽  
Shengfa Liu ◽  
Xuefa Shi ◽  
Che Abd Rahim Mohamed
Keyword(s):  
Spatial Distribution ◽  
Water Column ◽  
Marine Sediment ◽  
Peninsular Malaysia ◽  
Andaman Sea ◽  
Anthropogenic Sources ◽  
Sunda Shelf ◽  
Radioactivity Level ◽  
The North ◽  
Malacca Strait

Abstract Radiochemical separation techniques were applied to measure 210Pb radioactivity in the samples to determine spatial distribution of total 210Pb radionuclide in surface sediments and water column for the main waters on the Sunda Shelf. The average 210Pb radioactivity level recorded from the Malacca Strait (MS) is significantly higher than the southern South China Sea (sSCS); this is attributed to the supply of input from the Andaman Sea in its northern areas, and massive terrestrial processes from bordering land masses. The results reveal that the decreasing trend of total 210Pb in Peninsular Malaysia’s marine sediment starts with the north maritime zone of Malacca Strait (64.28 ± 5.97 Bq/kg) > south maritime zone of Malacca Strait (50.88 ± 6.15 Bq/kg) > east maritime zone of sSCS (41.01 ± 3.07 Bq/kg) > south maritime zone of sSCS (40.78 ± 3.16 Bq/kg). The Kelantan and Pahang Deltas have been identified as two of the main anthropogenic sources of input for total 210Pb in the sSCS while atmospheric transboundary mobilization affecting total 210Pb in water column. In the Malacca Strait, however, the distribution of total 210Pb might be influenced mainly by in situ processes of the strait’s seafloor and sources origin of sediment.

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