Thrombolite and stromatolite reefs occur at several stratigraphic levels within the terminal Proterozoic Nama Group (c. 550–543 Ma) of central and southern Namibia. The reefs form integral parts of several carbonate platforms within the Nama Group, including the Kuibis platform of the northern Nama Basin (Zaris subbasin), and Huns platform (Witputs subbasin) of the southern Nama Basin. The reef...

Researchers have independently documented the effects of land use on rivers and threats to river management institutions, but the relationship between changes in institutional context and river condition is not well described. This study assesses the connections between resource management institutions, land use, and rivers by integrating social science, geospatial analysis, and geomorphology. ...

Subducted sediments play an important role in arc magmatism and crust–mantle recycling. Models of continental growth, continental composition, convergent margin magmatism and mantle heterogeneity all require a better understanding of the mass and chemical fluxes associated with subducting sediments. We have evaluated subducting sediments on a global basis in order to better define their chemica...

Calcareous sediments cored at Broken and Ninetyeast ridges in the eastern Indian Ocean reveal the transitions from calcareous ooze to chalk and from chalk to limestone. Based on downhole porosity trends and laboratory mechanical consolidation tests, the compaction and lithification of these sedimentary sections occur at stratigraphically shallower depths than comparable marine calcareous sectio...

Mercury (Hg) contamination is pervasive in aquatic ecosystems and its bioaccumulation may lead to severe health concerns for both wildlife and humans. In this study we quantify historical Hg fluxes to the profundal sediment of Seneca Lake, NY. Previous studies show that the highest surface sediment Hg concentrations occur here, near a major tributary, the Keuka Lake Outlet. This tributary hoste...

A well-preserved Cambrian section in the Zanskar Valley of northern India has previously been interpreted to record the transition from a passive to an active tectonic margin related to Cambrian–Ordovician orogenesis. This interpretation has been used to support the tectonostratigraphic interpretation of other successions across the Tethyan Himalaya. Our detailed paleoenvironmental analysis sig...

The Eocene-Oligocene transition (between ca. 34 and 33.5 Ma) is the most profound episode of lasting global change to have occurred since the end of the Cretaceous. Diverse geological evidence from around the world indicates cooling, ice growth, sea-level fall, and accelerated extinction at this time. Turnover in the oceanic plankton included the extinction of the foraminifer Family Hantkeninid...

Synechococcus strain GL24 is a unicellular cyanobacterium that was isolated from Fayetteville Green Lake, New York, a meromictic lake which has high Ca and SO(4) concentrations. Epicellular mineralization of Synechococcus cells in the lake is the mechanism by which extensive calcitic bioherms (or microbial reefs) have been formed on the lake's shore and a marl sediment has been built on the lak...

Using shells collected from a sediment trap series in the Madeira Basin, we investigate the effects of seasonal variation of temperature, productivity, and optimum growth conditions on calcification in three species of planktonic Foraminifera. The series covers an entire seasonal cycle and reflects conditions at the edge of the distribution of the studied species, manifesting more suitable grow...

Coastal erosion is increasing worldwide due to the frequency of extreme natural phenomena and excessive human exploitation. In this study, a small model experiment was conducted investigate solidification effects three enzyme sources—soybean urease, freshwater Bacillus pasteurella, seawater domesticated pasteurella—on coastal sediments their impacts in environment. The solidifying effect differ...