Interstitial Water Studies, Leg 15, Study of CO2 Released from Stored Deep-Sea Sediments

Tsou, Judy; Hammond, Douglas; Horowitz, R.M.

doi:10.2973/dsdp.proc.20.212.1973

“…7A), with a maximum rate of 24.77 nmol/cm 3 /d at the shallowest depth (0.125 mbsf), declining rapidly to 3.3 nmol/cmVd at 0.775 mbsf and then more gradually to 0.06 nmol/cπvVd at 5.52 mbsf. The maximum rate of sulfate reduction is low but comparable to pre-viously published rates for more productive sites such as inshore marine sites (0.2-2800 nmol/cirrVd; Senior et al, 1982;Parkes and Taylor, 1985;Parkes and Buckingham, 1986), and also with rates from continental shelf surface sediments (0.0001^46 nmol/cπvVd; Sorokin, 1962, Tsou et al, 1973Goldhaber and Kaplan, 1975;J0rgensen, 1983;Parkes and Taylor, 1985;Edenborn et al, 1987;Cragg et al, 1990). Sulfate reduction is present at all depths to 424.9 mbsf (Fig.…”

Section: Potential Activitiessupporting

confidence: 78%

Bacterial Biomass and Activity in the Deep Sediment Layers of the Japan Sea, Hole 798B

Cragg¹,

Harvey²,

Fry³

et al. 1992

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

Sediment whole-round cores from a dedicated hole (798B) were obtained for detailed microbiological analysis, down to 518 m below the seafloor (mbsf) These sediments have characteristic bacterial profiles in the top 6 mbsf, with high but rapidly decreasing bacterial populations (total and dividing bacteria, and concentrations of different types of viable heterotrophic bacteria) and potential bacterial activities. Rates of thymidine incorporation into bacterial DNA and anaerobic sulfate reduction are high in the surface sediments and decrease rapidly down to 3 mbsf. Methanogenesis from CO 2 /H 2 peaks below the maximum in sulfate reduction and although it decreases markedly down the core, is present at low rates at all but one depth. Consistent with these activities is the removal of pore-water sulfate, methane gas production, and accumulation of reduced sulfide species. Rates of decrease in bacterial populations slow down below 6 mbsf, and there are some distinct increases in bacterial populations and activities that continue over considerable depth intervals. These include a large and significant increase in total heterotrophic bacteria below 375 mbsf, which corresponds to an increase in the total bacterial population, bacterial viability, a small increase in potential rates of sulfate reduction, and the presence of thermogenic methane and other gases. Bacterial distributions seem to be controlled by the availability of terminal electron acceptors (e.g., sulfate), the bioavailability of organic carbon (which may be related to the dark/light bands within the sediment), and biological and geothermal methane production. Significant bacterial populations are present even in the deepest samples (518 mbsf) and hence it seems likely that bacteria may continue to be present and active much deeper than the sediments studied here. These results confirm and extend our previous results of bacterial activity within deep sediments of the Peru Margin from Leg 112, and to our knowledge this is the first comprehensive report of the presence of active bacterial populations from the sediment surface to in excess of 500 mbsf and sediments > 4 m.y. old.

show abstract

“…7A), with a maximum rate of 24.77 nmol/cm 3 /d at the shallowest depth (0.125 mbsf), declining rapidly to 3.3 nmol/cmVd at 0.775 mbsf and then more gradually to 0.06 nmol/cπvVd at 5.52 mbsf. The maximum rate of sulfate reduction is low but comparable to previously published rates for more productive sites such as inshore marine sites (0.2-2800 nmol/cirrVd; Senior et al, 1982;Parkes and Taylor, 1985;Parkes and Buckingham, 1986), and also with rates from continental shelf surface sediments (0.0001^46 nmol/cπvVd; Sorokin, 1962, Tsou et al, 1973Goldhaber and Kaplan, 1975;J0rgensen, 1983;Parkes and Taylor, 1985;Edenborn et al, 1987;Cragg et al, 1990). Sulfate reduction is present at all depths to 424.9 mbsf (Fig.…”

Section: Potential Activitiessupporting

confidence: 55%

Bacterial Biomass and Activity in the Deep Sediment Layers of the Japan Sea, Hole 798B

Cragg¹,

Harvey²,

Fry³

et al. 1992

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

Sediment whole-round cores from a dedicated hole (798B) were obtained for detailed microbiological analysis, down to 518 m below the seafloor (mbsf) These sediments have characteristic bacterial profiles in the top 6 mbsf, with high but rapidly decreasing bacterial populations (total and dividing bacteria, and concentrations of different types of viable heterotrophic bacteria) and potential bacterial activities. Rates of thymidine incorporation into bacterial DNA and anaerobic sulfate reduction are high in the surface sediments and decrease rapidly down to 3 mbsf. Methanogenesis from CO 2 /H 2 peaks below the maximum in sulfate reduction and although it decreases markedly down the core, is present at low rates at all but one depth. Consistent with these activities is the removal of pore-water sulfate, methane gas production, and accumulation of reduced sulfide species. Rates of decrease in bacterial populations slow down below 6 mbsf, and there are some distinct increases in bacterial populations and activities that continue over considerable depth intervals. These include a large and significant increase in total heterotrophic bacteria below 375 mbsf, which corresponds to an increase in the total bacterial population, bacterial viability, a small increase in potential rates of sulfate reduction, and the presence of thermogenic methane and other gases. Bacterial distributions seem to be controlled by the availability of terminal electron acceptors (e.g., sulfate), the bioavailability of organic carbon (which may be related to the dark/light bands within the sediment), and biological and geothermal methane production. Significant bacterial populations are present even in the deepest samples (518 mbsf) and hence it seems likely that bacteria may continue to be present and active much deeper than the sediments studied here. These results confirm and extend our previous results of bacterial activity within deep sediments of the Peru Margin from Leg 112, and to our knowledge this is the first comprehensive report of the presence of active bacterial populations from the sediment surface to in excess of 500 mbsf and sediments > 4 m.y. old.

show abstract

“…Calculations (Tsou et al, 1973) indicate that the rates of bacterial metabolism at depths greater than a few meters must be very slow (10~8 moles liter~ yr~1) to produce the noted small effects over the long time periods available. It would seem, therefore, that the presence of relatively small numbers of bacteria, coupled with the greatly reduced metabolic rates noted by Jannasch and Wirsen (1977) for barotolerant bacteria, could readily account for the slow but steady destruction of organic material in deep-sea sediments.…”

Section: Nutrient Value Of Sedimented Organic Materialsmentioning

confidence: 99%

Carbon and Nitrogen Profiles in Deep-Sea Sediments: New Evidence for Bacterial Diagenesis at Great Depths of Burial

Waples¹,

Sloan²

1980

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

The sediments penetrated on Leg 58 of the Deep Sea Drilling Project in the Philippine Sea represent long periods of geologic time during which depositional conditions apparently remained very constant.Organic carbon and nitrogen contents of the sediments decrease with increasing depth of burial, before leveling off at minimum values of about 0.05 to 0.10 per cent and 0.01 per cent, respectively. The depth at which the minimum values are reached varies from site to site, but ages of sediments corresponding to the minima are all about 5 m.y.We infer that slow bacterial diagenesis is responsible for the gradual depletion of organic carbon and nitrogen. It is likely that the rate of bacterial metabolism is controlled by the rate of diffusion of electron acceptors within the sediments.These results suggest that bacterial ecosystems in deep-water sediments play a much more important role in diagenesis than has previously been thought.

show abstract

Interstitial Water Studies, Leg 15, Study of CO2 Released from Stored Deep-Sea Sediments

Cited by 3 publications

References 4 publications

Bacterial Biomass and Activity in the Deep Sediment Layers of the Japan Sea, Hole 798B

Bacterial Biomass and Activity in the Deep Sediment Layers of the Japan Sea, Hole 798B

Bacterial Biomass and Activity in the Deep Sediment Layers of the Japan Sea, Hole 798B

Carbon and Nitrogen Profiles in Deep-Sea Sediments: New Evidence for Bacterial Diagenesis at Great Depths of Burial

Contact Info

Product

Resources

About