Introduction to the Subseafloor Database
This website provides ready access to geochemical and geophysical information to help scientists assess the kinds of microbial communities and the levels and kinds of microbial activity that are likely to exist in marine sediments of different regions at different depths beneath the seafloor. This information is also intended to help scientists identify chemical species and geological regimes that should be examined in greater detail to more fully characterize the geochemical environment and activity of microbes in sediments throughout the world’s ocean basins.
The Biogeochemical Database
Sediment biogeochemical data may be used to predict burial depths and geographic regions in which specific microbial communities, such as communities with active sulfate reducers, MnO2 reducers, methanogenic microbes, or anaerobic methanotrophs, can be most effectively targeted and recovered. Biogeochemical data in this website include porewater concentrations of SO42- and NO3- (electron acceptors) and dissolved manganese and iron (inferred to be products of MnO2 and Fe-oxide reduction). The compiled data also include headspace concentrations of CH4 (a product of methanogenesis and an electron donor). These biogeochemical data are presented in two forms on the website: as profiles from individual sites, automatically drafted on demand, and in global maps that integrate data from the entire database. Some of these maps show the global distribution of Ocean Drilling Program (ODP) and Deep Sea Drilling Project (DSDP) sites where concentrations of the individual chemical species were measured in porewater samples. Additional SO42- and CH4 maps exhibit global patterns of edited concentration data.
The Geothermal Database
The website also contains global maps of estimated sediment depths for several isotherms that may be useful for studies of subseafloor microbial communities (30°C, 60°C, 90°C, and 120°C isotherms). Because there are distinct temperature limits for different microbial classes, estimates of subsurface temperatures may be useful for identifying drilling targets of special microbiological interest. For example, they may be used to predict geographic regions and sediment depths where active microbial communities in deep-sea sediments might be mesophilic, thermophilic, or hyperthermophilic. They might also be used to inform the search for anaerobic communities strongly supported by chemolithotrophy and the search for the upper thermal limit to life in deeply buried deep-sea sediments.
Explore Sediment Isotherms