Profiles of dissolved organic carbon (DOC) were measured in the pore water of sediments from 1000, 2000 and 3500 m water depth in the eastern North Atlantic. A net DOC accumulation in the pore waters was observed, which followed closely the zonation of microbial respiration in these sediments. The concentration of pore water DOC in the zone of oxic respiration was elevated relative to that in t...

Ecological evidence suggests that heterotrophic diazotrophs fueled by organic carbon respiration in sediments play an important role in marine nitrogen fixation. However, fundamental knowledge about the identities, abundance, diversity, biogeography, and controlling environmental factors of nitrogen-fixing communities in open ocean sediments is still elusive. Surprisingly, little is known also ...

Microplastics are small plastic particles (<1 mm) originating from the degradation of larger plastic debris. These microplastics have been accumulating in the marine environment for decades and have been detected throughout the water column and in sublittoral and beach sediments worldwide. However, up to now, it has never been established whether microplastic presence in sediments is limited to...

In the absence of fractures, methane bubbles in deep-water sediments can be immovably trapped within a porous matrix by surface tension. The dominant mechanism of transfer of gas mass therefore becomes the diffusion of gas molecules through porewater. The accurate description of this process requires non-Fickian diffusion to be accounted for, including both thermal diffusion and gravitational a...

The Yazd-Ardakan basin in Central Iran has two separated aquifers. The shallow unconfined aquifer is supplies 40 Qanats. The deep saturated confined aquifer is the main water storage. Due to over-withdrawal, water table has been decreasing during last 25 years. Recent study shows that the shortage of the aquifer is about 16 meters and land subsidence is 0.5 1.2 meters. Long deep cracks are foun...

[1] The phosphorus budget of the prehuman modern ocean is constrained applying the most recent estimates of the natural riverine, eolian, and ice‐rafted input fluxes; the phosphorus burial in marine sediments; and the hydrothermal removal of dissolved phosphate from the deep ocean. This review of current flux estimates indicates that the phosphorus budget of the ocean is unbalanced since the ac...

Baltic Sea deep water and sediments hold one of the largest anthropogenically induced hypoxic areas in the world. High nutrient input and low water exchange result in eutrophication and oxygen depletion below the halocline. As a consequence at Landsort Deep, the deepest point of the Baltic Sea, anoxia in the sediments has been a persistent condition over the past decades. Given that microbial c...

Reactive phosphorus undergoes diagenetic transformation once transferred into marine sediments. The degree of regeneration and redistribution of phosphorus depends on early diagenetic and environmental conditions, which may be linked to larger scale phenomena, such as bottom water circulation, water column ventilation, and organic carbon flux. Phosphorus phases of the 50m-sized fraction of deep...

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...

A study was carried out on the occurrence of chitinolytic bacteria inhabiting surface water, water above the sediment and bottom sediments of lakes: Jeziorak, Jeziorak Maty and Tynwald. The greatest amounts of them were found in demersal water and in bottom sediment surface stratum. However, the percentage share of chitinolytic bacteria proved greater in deep water (9.35%) than in bottom sedime...