The sediments of the North Atlantic north of 45°N do not seem to have attracted widespread attention prior to 1940, when Bramlette and Bradley published the results of their studies of cores obtained between Ireland and Newfoundland by the cable ship Lord Kelvin (Bramlette and Bradley, 1940). Since that time, however, a wealth of information concerning the sediments of this region has been gath...

Mercury cycling in the water column and upper sediments of a contaminated area, the Largo do Laranjo, Aveiro (Portugal), was evaluated after determination of reactive and non-reactive mercury concentrations in the water column and pore waters of sediments, collected in several places of this bay. In the water column, reactive mercury concentrations varied between 10 and 37 pmol dm(-3), the high...

Thomas M. Iliffe Bermuda Biological Station for Research Ferry Reach GE 01, Bermuda Significant biological and geological discoveries have resulted from the use of specialized cave diving techniques for the exploration and study of anchialine caves. Many new and higher taxa of troglobitic organisms have been found, some of which are relic "living fossils". Marine troglobites have at least three...

7.03.3 SOURCES AND DIAGENESIS OF SHOAL-WATER CARBONATE-RICH SEDIMENTS 75 7.03.3.1 Sources of Shoal-water Carbonates 75 7.03.3.1.1 General considerations 75 7.03.3.1.2 Sources of carbonate muds 76 7.03.3.1.3 Formation of carbonate sands 76 7.03.3.2 Early Marine Diagenesis of Shoal-water Carbonate-rich Sediments 77 7.03.3.2.1 Pore-water chemistry 77 7.03.3.2.2 Precipitation of early carbonate cem...

measurement of availability and mobility of heavy metals in river sediments is required in order to understand the behavior of these metals and to prevent potential toxic hazards. leaching column experiments were conducted for four sediment samples to determine the degree of mobility and the distribution of zn, cd, ni, cu, and pb because of an application of spiked heavy metals in sediments. se...

Vitamin B1, or thiamin, can limit primary productivity in marine environments, however the major marine environmental sources of this essential coenzyme remain largely unknown. Vitamin B1 can only be produced by organisms that possess its complete synthesis pathway, while other organisms meet their cellular B1 quota by scavenging the coenzyme from exogenous sources. Due to high bacterial cell d...

The objectives of this study were to investigate the seasonal and spatial variations of heavy metal pollution in the overlying water and surface sediments of the Tiaozi River, a tributary of the Liao River, which is one of the seven major rivers and one of the most heavily-polluted rivers in China. Water and sediment samples were collected over four seasons, analyzed for heavy metals (Pb, Cu, N...

Lake Vostok, the 7(th) largest (by volume) and 4(th) deepest lake on Earth, is covered by more than 3,700 m of ice, making it the largest subglacial lake known. The combination of cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier), limited nutrients and complete darkness presents extreme challenges to life. Here, we report metagenomic/metatranscriptomic seq...

Ocean margin sediments have been considered as important sources of dissolved organic carbon (DOC) to the deep ocean, yet the contribution from advective settings has just started to be acknowledged. Here we present evidence showing that near-surface heating of sediment in the Guaymas Basin, a young extensional depression, causes mass production and discharge of reactive dissolved organic matte...

Uranium behaves as a nearly conservative element in oxygenated seawater, but it is precipitated under chemically reducing conditions that occur in sediments underlying low-oxygen bottom water or in sediments receiving high fluxes of particulate organic carbon. Sites characterized by a range of bottom-water oxygen (BWO) and organic carbon flux (OCF) were studied to better understand the conditio...