(Table T2) Sulfur isotopes of pore water from ODP Leg 201 sites

Fifty-seven interstitial water samples from six sites (Ocean Drilling Program Sites 1225-1229 and 1231) in the eastern equatorial Pacific Ocean and the Peru margin were analyzed for the stable sulfur isotopic composition (34S/32S) of dissolved sulfate along with major and minor ions. With the exception of Site 1231, sulfate from the interstitial fluids (d34S values as much as 89 per mil vs. the SF6-based Vienna-Canyon Diablo troilite standard) is found at depth to be enriched in 34S with respect to modern seawater sulfate (d34S = ~21 per mil), indicating that microbial sulfate reduction (MSR) took place to different extents at all investigated sites. Deeper sediments at Sites 1228 and 1229 are additionally influenced by diffusion of a sulfate-rich brine that has already undergone sulfate reduction. The intensity of MSR depends on the availability of substrate (organic matter), sedimentation conditions, and the active bacterial community structure. Formation of isotopically heavy diagenetic barite at the sulfate-methane transition zone is expected at Sites 1227 (one front), 1229 (two fronts), and probably Site 1228. At Site 1231, the constant sulfur isotopic composition of sulfate and concentrations of minor pore water ions indicate that suboxic (essentially iron and manganese oxide based) diagenesis dominates and no net MSR occurs.

Susceptibility, magnetization and S-ratio of ODP Sites 201-1225 and 201-1227

Samples were collected at Sites 1225 and 1227 to investigate the occurrence of fine-grained, biogenic magnetic particles (magnetosomes). Several magnetic methods, including anhysteretic remanent magnetization and isothermal remanent magnetization, were used to characterize the main magnetic carriers in the samples. Extracts were made to isolate the fine-grained fraction, which was then examined under a transmission electron microscope. Grains with the unique characteristics of magnetosomes were found in samples from regions in the core with both high and low concentrations of magnetic minerals. This suggests they have the potential to be a persistent proxy of paleoredox conditions.

(Table T1) Dissolved carbohydrate concentrations of interstitial waters from seven ODP Leg 201 sites

Total dissolved carbohydrates (DCHOs) were determined in interstitial waters collected at open-ocean and Peru margin sites cored during Ocean Drilling Program Leg 201. Concentrations of DCHOs ranged from 0 to ~1500 µM and showed no consistent trends between open-ocean and Peru margin sites either in the magnitude or direction of downhole interstitial water gradients. In contrast, relative DCHO concentrations (normalized to dissolved organic carbon concentrations) were higher in open-ocean vs. margin sediments. These trends are consistent with results from more shallow estuarine and nearshore continental margin sediments and may be related to changes in the overall controls on sediment organic matter remineralization with decreasing remineralization rates.

(Table T1) Amino acid ratios and concentrations in interstitial waters of seven ODP Leg 201 sites

Proteins and their amino acid building blocks form a major group of biomolecules in all organisms. In the sedimentary environment, proteins and amino acids have two sources: (1) soft tissues and detritus and (2) biotic skeletal structures, dominantly from calcium carbonate-secreting organisms. The focus of this report is on D/L ratios and concentrations of selected amino acids in interstitial waters collected during ODP Leg 201. The Peru margin sites are generally low in carbonates, whereas the open-ocean sites are more carbonate rich. Seifert et al. (1990, doi:10.2973/odp.proc.sr.112.152.1990) reported amino acid concentrations in interstitial waters from Site 681 (ODP Leg 112) comparable to Leg 201 Site 1229.