Fluxes of dissolved organic carbon (DOC) from marine sediments represent a poorly constrained component of the oceanic carbon cycle that may affect the concentration and composition of DOC in the ocean. Here we report the first in situ measurements of DOC fluxes from continental margin sediments (water depths ranging from 95 to 3,700 m), and compare these fluxes with measured benthic fluxes fro...

background: the most important factors and problems threatening the anzali wetland are the contaminant load and sediments entering the wetland, as well as lack of an integrated management plan for this wetland. the main objectives of the current research were to explore whether there are significant differences in concentrations of zn, cd, and pb in surface sediments among different sites (base...

water and sediment samples were collected from six different stations, located along the nil river between february and june 2015. concentrations of cadmium, lead, zinc, and copper were determined. the extent of the sediment pollution was assessed, using the multiple pollution indices, namely contamination factor (cf), pollution load index (pli), and the geoaccumulation index (igeo). the result...

since heavy metals are considered as one of the major pollutants threatening, the main goal of this study was to bring out the concentrations of pb, zn and mn in the surface sediments off bushehr in the persian gulf. for this purpose, after collection of samples, the concentrations of the three metals in surface sediments were measured through the atomic absorption. the results were compared wi...

pollution of marine waters is one of the important issues that has a irreparable effects. also, in the organic oil pollutants, due to inappropriate effects on the environment and humans health and ability to create cancer, hydro carbons of polycyclic (pahs) and heavy metals (ni,hg,v) have a particular importance. according to the importance of study of the environ mental contaminants in the fou...

Ocean Drilling Program Leg 201 was the first ocean drilling expedition dedicated to the study of life deep beneath the seafloor. Its seven sites were selected to represent the general range of subsurface environments that exist in marine sediments throughout most of the world’s oceans. In water depths as great as 5300 m and as shallow as 150 m, the expedition drilled as deep as 420 m into ocean...

We report on biomarker responses conducted as part of a multi-level assessment of the chronic toxicity of estuarine sediments to the amphipod Gammarus locusta. A companion article accounts for organism and population-level effects. Five moderately contaminated sediments from two Portuguese estuaries, Sado and Tagus, were assessed. Three of them were muddy and two were sandy sediments. The objec...

Focusing on Xujiaweizi fault depression, the geological conditions and geochemical characteristics of deep natural gas formation in north Songliao basin are evaluated, resources estimated, favorable areas optimized. Shahezi Formation shale is a set coal bearing sediments with high organic matter abundance (TOC 1%～12%), over maturity (Ro 1%～4%) shore shallow lake facies, which mainly distributed...

Depth variations of total mercury (Hg) and methylmercury (MeHg) concentrations were obtained in cores from nonvegetated sediments, sediments colonized by Sarcocornia fruticosa, Halimione portulacoides, and Spartina maritima and below-ground biomass in three Portuguese estuaries. Similar analyses were also performed on the above-ground plant tissues. Concentrations in below-ground biomass exceed...

The distribution of grain size parameters along 11 km stretch of the beach sediments between Karikal and Nagore, reveals that the mean grain size exhibits a marked decreasing trend on either side of the mouth of the Tirumalairajanar River which flow from west to east. The sediments are mainly of medium to coarse grained, moderately sorted, near-symmetrical skewed to fine skewed and leptokurtic ...