Silty Sand Sediments Research Articles

Global Warming Potential of Carbon dioxide and Methane Emission from Mangrove Sediment in Waiheru Coastal, Ambon Bay.

Mangroves can store carbon. However, it also produces carbon emissions by degrading organic matter in mangrove sediments. This research was conducted in a mangrove ecosystem at Waiheru, in the inner Ambon bay, to determine CO2 and CH4 emissions and their potential for global warming (GWP) from mangrove sediments. Gas is taken through a syringe mounted on the hood. Gas concentration analysis used the gas chromatography method, while the average gas concentration in each sediment was tested using ANOVA Single Factor. The results showed that the average concentration of CO2 gas was significantly different for each sediment (P-value <0.05), while the average concentration of CH4 gas was not significantly different (P-value >0.05). The largest CO2 gas emission in mangrove sediments in Waiheru Village was found in sandy mud sediments with an emission value of 136.99 mg.m−2.h−1, and the lowest was in sand sediments, namely 13.01 mg.m−2.h−1. Meanwhile, the largest emission of CH4 gas was in silty sand sediments, namely 0.32 mg.m−2.h−1, and the lowest was in sandy mud sediments, namely 0.15 mg.m−2.h−1. Fluctuations in carbon gas emissions in each sediment are inversely proportional, which indicates that the formation of CH4 gas is obtained through ethanol reduction, which utilizes CO2 gas concentrations. The total GWP in the mangrove sediments of Waiheru Village is 231.58 mg.m−2.h−1. The GWP contributed by the type of sandy silt sediment was 140.72 CO2-eq mg.m−2.h−1, muddy sand was 70.95 mg.m−2.h−1, and sand sediment was 19.91 CO2-eq mg.m−2. h−1.

Temperature-Induced Environmental Chain Reaction in Marine Sedimentation and Its Impact on Manila Clam Ruditapes philippinarum

Marine Heatwaves (MHWs) events have been increasing, causing severe impacts on marine ecosystems and aquaculture. In this study, the effects of temperature on changes in sediment dissolved oxygen (DO) and hydrogen sulfide (H2S) concentrations and their effects on the behavioral and physiological responses of a bivalve were investigated by simulating different sudden summer temperature change conditions. The results showed that temperature was an important factor affecting DO consumption and H2S release in sediments, and sediment type also played a key role. At higher temperatures, DO was consumed more rapidly and H2S release increased in sediments, and the DO was consumed and H2S released in sandy sediments was less than in silty sand sediments. The response of Manila clam’s exercise behavior under environmental pressure was also rapid. The excavation index of the Manila clam decreased with the DO consumption, indicating that the Manila clam could alter its burial depth and move toward the sediment-water interface when stressed. Compared with phenol oxidases (PO) activity being activated under experimental conditions, succinate concentrations only increased slightly at 32°C, and did not surpass the threshold indicative of anaerobic metabolism. However, when toxic substances such as H2S start to accumulate, they may damage the immune system and tissues of the Manila clam, thereby affecting its future survival. Therefore, when temperatures are high for long periods in summer, it is necessary to take timely action to prevent and guard against harm caused by DO and H2S to aquaculture organisms.

Assessment of the Effect of Skin Friction on the Results of Dynamic Penetration Testing in Cohesionless Soil

Dynamic cone penetration (DCP) is a field test that is used as a substitute for other penetration tests because it is portable, low cost, quick and simple to use. However, the effect of skin friction can significantly influence the accuracy of the test results. The current study investigated the effect of skin friction through field testing on silt and fine sand deposits. The tests were initially conducted at different energy levels using seven cones with different geometries. The optimal cone was selected after ascertaining the repeatability of the test results. The effect of soil collapse around the rods, as an important factor causing error in the results, was addressed by recording the torsion and developing a correction coefficient. Finally, the model was verified at different sites featuring silty sand sediment where the predicted values showed good compliance with the measured DCPT results.

Functional trait composition and diversity patterns of marine macrobenthos across the Arctic Bering Sea

The use of functional trait analysis has been advocated to uncover the global mechanisms behind biodiversity responses to environmental variation, but the application of this approach to the Arctic macrobenthic community is underdeveloped relative to that used for other organism groups. Based on several summer surveys (July to September 2010, 2012, 2014 and 2016) in the Bering Sea, we used biological trait analysis (BTA) to quantify the composition and diversity of macrobenthic biological traits along an environmental gradient ranging from the shallowest portion of the continental shelf to the shelf break and deep basin. Our results show a clear shift in the macrobenthic functional composition through the application of abundance- and biomass-based measurements in six different subregions of the Bering Sea. The macrobenthic community of the south-western shelf and shelf break of the Bering Sea, an area with silty-sand sediment, was mainly composed of taxa characterized by high body flexibility, vermiform, and tube-dweller/burrower modalities or large, semi-motile, deposit feeder and flattened dorsally modalities. However, the community of the north-eastern shelf of the Bering Sea with sandy sediment was mainly characterized by organisms characterized as motile surface crawlers and carnivores/scavengers. Similar to the factors that determine the taxonomic distribution and composition of the macrobenthos, sediment composition and depth were found to be the main factors that affect the distribution of the macrobenthic functional structure in the study area. The species and functional diversity of the macrobenthos show a strong linear relationship, potentially indicating that the community exhibits relatively low functional redundancy and that the benthic ecosystem is vulnerable to species loss or regime shifts.

Rare earth elements in intertidal sediments of Bohai Bay, China: Concentration, fractionation and the influence of sediment texture

Surface sediments from intertidal Bohai Bay were assessed using a four-step sequential extraction procedure to determine their concentrations of rare earth elements (REEs) and the chemical forms in which those elements were present. The normalized ratios La/Gd and La/Yb showed that LREE contents were not significantly higher than the middle REEs or HREE contents. A negative Ce anomaly and positive Eu were observed in sand and silty sand sediments, whereas no significant Ce or Eu anomaly was found in clayey silt sediments. Residual fraction of REEs accounted for the majority of their total concentrations. Middle REEs were more easily leached than other REEs, especially in clayey silt sediment. REEs contents in the surface sediment from the intertidal Bohai Sea were consistent with data from the upper continental crust and China shallow sea sediments, indicating that they were generally unaffected by heavily anthropogenic effects from adjacent areas.

Nitrate pollution in the coastal aquifer system of the Korinthos Prefecture (Greece)

Over the last decades intensified agricultural production is applied in the northern coastal part of Korinthos Prefecture (Peloponnese, Greece). An aquifer system occurs in the recent basin deposits, which consists of unconsolidated material, namely sands, pebbles and fine clay to silty sand sediments. A network of production boreholes and wells distributed over the studied region were sampled in June 1998 and the waters analyzed for major ions, nitrites and ammonia. Quality deterioration was detected and attributed by crop overfertilization and use of abandoned shallow wells as septic tanks, inducing increased nitrogen compound concentrations. Nitrates are noticeable throughout the entire region rendering most of the analyzed waters improper for human consumption, as concentrations by far exceed 50 mg l-1. Mean nitrate concentration in the groundwater is 74 mg l-1 and the standard deviation 72. In general, low nitrate concentrations were observed in wet seasons.

Distribution of total carbohydrates in surface sediments of the Egyptian Mediterranean coast, in relation to some inorganic factors

The interrelation between calcium, magnesium, carbonate, fluoride and total carbohydrates (THCO) distribution was investigated for surface sediments collected from three sectors (A–C) along the Egyptian Mediterranean coast during the summer of 2008. The recent ultrasound-acetic acid technique was used for the simultaneous extraction and hydrolysis of total carbohydrates. Based on the average values, the sandy sediments of sector (C) exhibited the highest THCO levels (163.78±53.28μg/g). In contrast, the silty sand sediments of sector (A) had the lowest average THCO level (8.56±2.60μg/g). Linear regression model with one predictor showed that there are significant correlations between total carbohydrates, carbonate and fluoride suggesting the common origin of these components. Neither calcium nor magnesium has correlation with THCO. This study revealed that carbonate is the dominant factor affecting the distribution of carbohydrates in the sediments. The spatial distribution of THCO was not affected by the potential sources of runoff, but varied according to the sediments mineralogy.

Macrozoobenthos of two Antarctic glacial coves: a comparison with non-disturbed bottom areas

There are only few studies on shallow Antarctic benthic communities associated with habitats affected by intense mineral sedimentation inflow. The analysis of macrofaunal communities associated with two shallow, isolated glacial coves was performed in Admiralty Bay (King George Island) and compared with non-disturbed sites. Multivariate analyses (hierarchical classification, nMDS) clearly separated glacial cove communities (two assemblages) from the sites situated outside both basins (two assemblages). The community influenced by the streamflow of glacial discharge of meltwater situated in the area with sandy–clay–silt sediments had a very low species richness, diversity and abundance. It was dominated by eurytopic, motile deposit feeding polychaetes such as Mesospio moorei, Tharyx cincinnatus and Leitoscoloplos kerguelensis as well as the bivalve Yoldia eightsi. The second glacial community of the area located at a grater distance from the outlet of the stream was characterized by sandy–clay–silt and clay–silt deposits and showed also a low diversity and species richness. The most abundant here were peracarid crustaceans, with the dominant opportunistic feeder Cheirimedon femoratus. Community from the non-disturbed area with silty–clay–sand, and silty–sand sediments had higher species richness and diversity. The assemblage of fauna from the sandy bottom has values of those two indexes similar to those found in the disturbed areas.

Distribution and diversity of cumacean assemblages in Admiralty Bay, King George Island

Distribution and diversity of cumacean assemblages in Admiralty Bay, King George IslandEleven species of cumaceans were found in 105 samples collected in Admiralty Bay (King George Island) in the summers of 1984/85 and 1985/86, from 20 to 500 m depth range. Four cumacean assemblages were distinguished using the multivariate analysis. They were characterized by the dominance of one or two species often with low density values. Two assemblages were found in open waters of Admiralty Bay. The first inhabited on sandy-clay-silt and silty-clay-sand bottom deposits in the depth range from 140 to 330 m, withCampylaspis maculata(1.6 ± 2.1 ind./0.1m2; F = 72.4%) andLeuconsp. (1.4 ± 1.6 ind./0.1m2; F = 68.9%) as key species. The second assemblage was found in the depth range from 50 to 120 m with silty-sand sediments, and it was characterized by the presence of Vauthompsonia inermis (6.5 ± 6.6 ind./0.1m2; F = 92.0%). A third assemblage was found in shallow waters influenced by glaciers in the bottom area of Ezcurra Inlet. It was characterized by sandy-clay-silt sediments and the presence ofEudorella splendida(14.6 ± 9.4 ind./0.1m2; F = 100.0%) as a core species. The last assemblage was found in the shallow sublittoral (50-100 m) of Ezcurra Inlet and the central basin, withDiastylis anderssoni armata(1.5 ± 1.1 ind./0.1m2; F = 85.7%) andDiastylopsis goekei(1.1 ± 1.0 ind./0.1m2; F = 71.4%) as the most frequent and abundant species.V. inermisis considered a eurytopic species with high frequency in the whole material, and was present in all four distinguished assemblages.E. splendidaandD. goekeiwere also recorded in each of the assemblages, but their total frequency was lower.

Penyebaran dan Karakteristik Zirkon Dasar Laut sebagai Endapan Sekunder di Perairan Singkawang dan sekitarnya, Kalimantan Barat

DOI: 10.17014/ijog.v5i2.98The abundance of sea floor zircon mineral in the studied area was found at the southwest of Kabung Island (SKWL-56) which was accumulated in silty sand sediments at 23 m water depth. Based on the grain mineragraphy analysis, this mineral has various characteristics: rose, white, and brownish yellow colours, elongated prismatic crystals, and translucent to transparent appearances. The distribution profile lines have shown that the distribution of seafloor zircon tends to decrease from Kabung and its surrounding areas to Lemukutan, and from Kabung to the Land of Kalimantan. Considering the abundances, distribution, crystal shape, and mineral association, the zircon mineral in the studied area is a placer deposit that was produced by transport processes characterized by the changing form of crystal. Some samples observed, showed corrosion marks due to a transportation activity, while the transparent level change of these minerals was suggested to be due to much penetration into cavities in the mineral, which lead to the presence of gangue material during the deposition process.

Arsenic and fluoride in a loess aquifer in the central area of Argentina

The objective of this study is to analyze the geochemical conditions associated with the presence of arsenic (As) and fluoride (F) in the phreatic aquifer of Coronel Moldes, in the central sector of the Argentine Chacopampean plain. The studied aquifer is composed of silty sand sediments of aeolian origin, typically loess-like sediments. The geochemical composition of water varies from sodium bicarbonate to sodium sulfate-chloride water. As contents range from low concentrations, below detection level, to 250 μg/l. High values of F (up to 12 mg/l) were recorded. A high As–F correlation was found (R 2 = 0.84). The pH varied from 7.31 to 8.85 and the nitrates reached concentrations up to 200 mg/l, indicating an oxidant environment. The highest values of As and F agreed with sodium bicarbonate waters as well as with the highest values of pH recorded. There was a high correlation between As and F− as well as between As and the Na/Ca ratio. The composition and texture of loess, low permeability and hydraulic gradients together with the geochemical features of sodium bicarbonate waters are proper conditions for the mobilization of As and F in groundwater in the central area of Argentina.

DISTRIBUSI SUSPENSI DAN SEDIMEN DI TELUK JAKARTA DAN PERAIRAN KEPULAUAN SERIBU

The objectives of this study were to know total suspended solid (TSS) and sediment distributions in Jakarta bay and Seribu Islands waters. This study was conducted on 5-11 August 2003. Water samples for TSS measurement were taken from the water surface (2 m depth), 1 m upper the bottom surface, and in the middle of water column in each station. The highest TSS was found at 0.75 g/l on the water surface in front of the westside of Cengkareng drain. In Seribu Island waters, TSS was lower than 0.07 g/l. High TSS in the middle of water column were found in the north of Untung Jawa Island, Rambut Island waters, and north of Cengkareng drain. The highest TSS in the middle of water column reached 0.0324 g/l in surrounding Muara Angke waters. On the other hand, low TSSs in the middle of water column were found in the east of Untung Jawa Island and in the west of Rambut Island at around 0.0268 g/l. On the bottom, high TSSs were found in the most east of Bidadari and Karang Ubi Islands at 0.23 g/l. Low TSSs at around 0.02 g/l were found in the east and southeast of Untung Jawa Island and the north part of sampling location in this study. Silty mud sediment was observed in the northwest of Cengkareng drain estuary. In the surrounding Dadap and Kamal estuaries, silt, sandy silt, sand, and silty sand sediments were gradually found. Distribution of muddy sand sediment was found very narrow in the Jakarta Bay, but wider in the north of Tanjung Pasir. Silty sand, sand, sandy silt, and silt sediment were observed in the north part of sampling location in this study.The objectives of this study were to know total suspended solid (TSS) and sediment distributions in Jakarta bay and Seribu Islands waters. This study was conducted on 5-11 August 2003. Water samples for TSS measurement were taken from the water surface (2 m depth), 1 m upper the bottom surface, and in the middle of water column in each station. The highest TSS was found at 0.75 g/l on the water surface in front of the westside of Cengkareng drain. In Seribu Island waters, TSS was lower than 0.07 g/l. High TSS in the middle of water column were found in the north of Untung Jawa Island, Rambut Island waters, and north of Cengkareng drain. The highest TSS in the middle of water column reached 0.0324 g/l in surrounding Muara Angke waters. On the other hand, low TSSs in the middle of water column were found in the east of Untung Jawa Island and in the west of Rambut Island at around 0.0268 g/l. On the bottom, high TSSs were found in the most east of Bidadari and Karang Ubi Islands at 0.23 g/l. Low TSSs at around 0.02 g/l were found in the east and southeast of Untung Jawa Island and the north part of sampling location in this study. Silty mud sediment was observed in the northwest of Cengkareng drain estuary. In the surrounding Dadap and Kamal estuaries, silt, sandy silt, sand, and silty sand sediments were gradually found. Distribution of muddy sand sediment was found very narrow in the Jakarta Bay, but wider in the north of Tanjung Pasir. Silty sand, sand, sandy silt, and silt sediment were observed in the north part of sampling location in this study.

Micro-craters in muddy tidal flats of cold regions

Meltwaters dripping from overhanging ice cakes, stranded at low tide on muddy tidal flats of the St.Lawrence Estuary, near Québec City, cause micro-craters to form on soft mud and silty-sand sediments. The shallow depressions are circular, symmetrical, and with rims a few mm high, some have a tiny hole centered in the bottom. Craters range from 7 to 15 cm in diameter, and 20 to 50 mm in depth ; they characterize tidal flats of cold regions.

Acoustic penetration of a silty sand sediment in the 1-10-kHz band

An experiment was performed to measure sediment penetrating acoustic waves to test a model of acoustic propagation, which is based on Biot's theory. Independent geophysical measurements provided model input parameters. A parametric sound source was used to project a narrow beam pulse into a silty sand sediment at a shallow grazing angle. The sediment acoustic waves were measured by an array of buried sensors and processed to measure wave directions and speeds. Two acoustic waves were observed, corresponding to the fast and slow waves predicted by Biot's theory. Discrepancies between model predictions and measured acoustic waves were examined, deficiencies in the model identified, and strategies for improvement postulated. The permeability and bulk modulus of the solid frame were of particular interest.

Pore‐water pressure change in submarine sediments due to waves

Abstract The pore‐water pressure was measured in disturbed silty sand sediment at 1.5 m depth below the sea floor in about 12 m water depth, concurrently with monitoring of wave pressure in the water at about 10 m above the sea floor, over the period 1976–1978 in Shimizu Harbor, Central Japan. The piezometer was designed to measure perturbation of a minimum differential pore‐water pressure of 2 g/cm2 (0.196 kPa, 2 cm water head) and a maximum of 0.1 kg/cm2 (9.8 kPa, 1 m water head) from the wave pressure at the sea floor. The measured surface wave had periods of 4–20 seconds and heights of 50–100 cm. The wave pressure at the sea floor was transmitted to the pore‐water, being diminished to Vi to 4/s with a time lag at 1.5 m depth in the sediment. The damping was smaller for a long‐period wave than for a short‐period one. The time lag was relatively clear for long‐period waves. The forms of wave pressure were slightly different from the fluctuation forms of the differential pore‐water pressure. The damping transfer of the wave pressure to the pore‐water pressure in the submarine sediment will generate a change in the state of effective stress therein, and affect submarine slope stability.