Kg Of Sediment Research Articles

Asteroidea (Echinodermata) from the Oxfordian (Late Jurassic) of Savigna, Départment du Jura, France

The asteroid fauna from the Late Oxfordian marls (bifurcatus Zone, stenocycloides Subzone) of Savigna includes 11 taxa, distributed between 8 families, of which 1 (Plumasteridae) is new. A goniasterid of distinctive morphology, Hessaster longimarginalis, is described as new, as is an asteriid, Savignasterias villieri. The material was recovered by surface picking and processing over 1,000 kg of sediment, and includes 28 partial individuals and approximately 2,000 isolated ossicles in excellent preservation, which show fine details of the stereom architecture and additionally allow ontogenetic changes to be described. Detailed comparison with extant asteroids enables diverse ossicle types to be assigned precisely to individual taxa. The phylogenetic relationships of individual fossil species with living taxa are determined using characters derived from numerous skeletal elements, and it is shown that the benthopectinid and pterasterid species present in the Savigna fauna are basal to their respective families. In comparison with other assemblages collected from Jurassic clay facies, the Savigna asteroid fauna is unusually diverse. Importantly, the fauna includes elements typical of present day deep sea environments (bathyal and abyssal), living abundantly in Oxfordian shelf seas of about 50 m depth.

Influences of Organic Carbon Supply Rate on Uranium Bioreduction in Initially Oxidizing, Contaminated Sediment

Remediation of uranium-contaminated sediments through in situ stimulation of bioreduction to insoluble UO2 is a potential treatment strategy under active investigation. Previously, we found that newly reduced U(IV) can be reoxidized under reducing conditions sustained by a continuous supply of organic carbon (OC) because of residual reactive Fe(III) and enhanced U(VI) solubilitythrough complexation with carbonate generated through OC oxidation. That finding motivated this investigation directed at identifying a range of OC supply rates that is optimal for establishing U bioreduction and immobilization in initially oxidizing sediments. The effects of OC supply rate, from 0 to 580 mmol of OC (kg of sediment)(-1) year(-1), and OC form (lactate and acetate) on U bioreduction were tested in flow-through columns containing U-contaminated sediments. An intermediate supply rate on the order of 150 mmol of OC (kg of sediment)(-1) year(-1) was determined to be most effective at immobilizing U. At lower OC supply rates, U bioreduction was not achieved, and U(VI) solubilitywas enhanced by complexation with carbonate (from OC oxidation). At the highest OC supply rate, the resulting highly carbonate-enriched solutions also supported elevated levels of U(VI), even though strongly reducing conditions were established. Lactate and acetate were found to have very similar geochemical impacts on effluent U concentrations (and other measured chemical species), when compared at equivalent OC supply rates. While the catalysts of U(VI) reduction to U(IV) are presumably bacteria, the composition of the bacterial community,the Fe-reducing community, and the sulfate-reducing community had no direct relationship with effluent U concentrations. The OC supply rate has competing effects of driving reduction of U(VI) to low-solubility U(IV) solids, as well as causing formation of highly soluble U(VI)-carbonato complexes. These offsetting influences will require careful control of OC supply rates in order to optimize bioreduction-based U stabilization.

The constructive functions of tropical cyclones and tsunamis on deep-water sand deposition during sea level highstand: Implications for petroleum exploration

Empirical data on tropical cyclones (meteorological phenomena) and tsunamis (oceanographic phenomena) from the Indian, Atlantic, and Pacific Oceans reveal that they are highly powerful and frequent events during the present sea level highstand. Tropical cyclones have the power to stir up the entire water column across the United States Atlantic continental shelf, which is 100 km (62 mi) wide and 200 m (656 ft) deep at the shelf edge. Maximum measured velocities of cyclone-triggered bottom flows are commonly in the range of 100–300 cm s1 (39–117 in. s1) on the shelf and 200–7000 cm s1 (78–2730 in. s1) in submarine canyons and troughs. At these high velocities, even gravel-size grains would be eroded and transported. Data also reveal that tropical cyclones accelerate deep-water siliciclastic deposition by transporting sediment seaward across the open shelf, over the shelf edge, and via submarine canyons into deep-water environments during the present highstand. Modern shelf edges are composed of both relict and active sand bodies that are suitable for delivering sand and gravel into the deep sea. Estimates suggest that 200,000 tropical cyclones (Bay of Bengal [Indian Ocean] and Atlantic Ocean) and 140,000 tsunamis (Pacific Ocean) would have occurred during the present highstand interval. During Hurricane Hugo (September 1989), more than 2 million kg of sediments were flushed down the Salt River Submarine Canyon (St. Croix, U.S. Virgin Islands) into deep water. Although cyclones and tsunamis could have a significant impact on developing deep-water siliciclastic and calciclastic reservoirs in equatorial regions during sea level highstand, such real-world possibilities have been overlooked by the petroleum industry.

Human-induced changes in animal populations and distributions, and the subsequent effects on fluvial systems

Humans have profoundly altered hydrological pathways and fluvial systems through their near-extirpation of native populations of animal species that strongly influenced hydrology and removal of surface sediment, and through the introduction of now-feral populations of animals that bring to bear a suite of different geomorphic effects on the fluvial system. In the category of effects of extirpation, examples are offered through an examination of the geomorphic effects and former spatial extent of beavers, bison, prairie dogs, and grizzly bears. Beavers entrapped hundreds of billions of cubic meters of sediment in North American stream systems prior to European contact. Individual bison wallows, that numbered in the range of 100 million wallows, each displaced up to 23 m 3 of sediment. Burrowing by prairie dogs displaced more than 5000 kg and possibly up to 67,500 kg of sediment per hectare. In the category of feral populations, the roles of feral rabbits, burros and horses, and pigs are highlighted. Much work remains to adequately quantify the geomorphic effects animals have on fluvial systems, but the influence is undeniable.

Description of the small plastics fragments in marine sediments along the Alang-Sosiya ship-breaking yard, India

This study aimed to assess the accumulation of small plastic debris in the intertidal sediments of the world's largest ship-breaking yard at Alang-Sosiya, India. Small plastics fragments were collected by flotation and separated according to their basic polymer type under a microscope, and subsequently identified by FT-IR spectroscopy as polyurethane, nylon, polystyrene, polyester and glass wool. The morphology of these materials was also studied using a scanning electron microscope. Overall, there were on average 81 mg of small plastics fragments per kg of sediment. The described plastic fragments are believed to have resulted directly from the ship-breaking activities at the site.

Suspended sediment fluxes in a tidal wetland: Measurement, controlling factors, and error analysis

Suspended sediment fluxes to and from tidal wetlands are of increasing concern because of habitat restoration efforts, wetland sustainability as sea level rises, and potential contaminant accumulation. We measured water and sediment fluxes through two channels on Browns Island, at the landward end of San Francisco Bay, United States, to determine the factors that control sediment fluxes on and off the island. In situ instrumentation was deployed between October 10 and November 13, 2003. Acoustic Doppler current profilers and the index velocity method were employed to calculate water fluxes. Suspended sediment concentrations (SSC) were determined with optical sensors and cross-sectional water sampling. All procedures were analyzed for their contribution to total error in the flux measurement. The inability to close the water balance and determination of constituent concentration were identified as the main sources of error; total error was 27% for net sediment flux. The water budget for the island was computed, with an unaccounted input of 0.20 m3s−1 (22% of mean inflow), after considering channel flow, change in water storage, evapotranspiration, and precipitation. The net imbalance may be a combination of groundwater seepage, overland flow, and flow through minor channels. Change of island water storage, caused by local variations in water surface elevation, dominated the tidally averaged water flux. These variations were mainly caused by wind and barometric pressure change, which alter regional water levels throughout the Sacramento-San Joaquin River Delta. Peak instantaneous ebb flow was 35% greater than peak flood flow, indicating an ebbdominant system, though dominance varied with the spring-neap cycle. SSC were controlled by wind-wave resuspension adjacent to the island and local tidal currents that mobilized sediment from the channel bed. During neap tides sediment was imported onto the island but during spring tides sediment was exported because the main channel became ebb dominant. Over the 34-d monitoring period 14,000 kg of suspended sediment were imported through the two channels. The water imbalance may affect the sediment balance if the unmeasured water transport pathways are capable of transporting large amounts of sediment. We estimate a maximum of 2,800 kg of sediment may have been exported through unmeasured pathways, giving a minimum ent import of 11,200 kg. Sediment flux measurements provide insight on tidal to fortnightly marsh sedimentation processes, especially in complex systems where sedimentation is spatially and temporally variable.

Role of riverine sediment and particulate matter in adsorption of heavy metals

Riverine sediments and suspended matters have been subjected to several bench scale tests for the evaluation of adsorption potential of heavy metals. For this purpose water, sediment and suspended particulate matters of Tadjan River (southern part of the Caspian Sea) were collected. In the vicinity of the river many polluting sources were recognized; for instance , pulp and paper mill, dairy factory and municipal sewage that can introduce various amounts of heavy metals into the river water. Bottom sediments and suspended particulate matters have been individually subjected to adsorption tests. The results of analy sis showed that riverine bottom sediments have greater potential for adsorbing heavy metals than suspended matters. However the trend of adsorption in both sediments and suspended matters are similar. Maximum adsorption capacity of heavy metals (in terms of mg of metal per kg of sediments and suspended matters) by sediments and suspended matters are as: Sediments : Cu (2200 )> Mn (2000 )> Ni (1400 )> Zn (320 ) Suspended matters : Cu (2100 )> Ni (1500 )> Mn (1200 )> Zn (310 ) Further, results revealed that increasin g concentration of metals would cause desorbing Cadmium from both sediments and suspended matters.

Use of SeaWiFS ocean color data to estimate neritic sediment mass transport from carbonate platforms for two hurricane-forced events

Plumes of neritic sediment caused by the passage of Hurricane Gert near Bermuda in 1999, and by the passage of Hurricane Michelle over Cuba’s Gulf of Batabano in 2001, were observed by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The mass of sediments in each of these plumes, which consist largely of neritic carbonate particles, was estimated using an algorithm for the calculation of suspended sediment concentrations. The Bermuda and Batabano plumes transported 0.22 and 1.2–1.35 million kg of sediment, respectively. The algorithm results were compared with the results from two other sediment mass algorithms and proved to be consistent. These results indicate the potential use of remote sensing to estimate carbonate flux from coral reefs and banks and atolls as an augmentation to in situ studies. In addition, the use of remote sensing data may improve estimates of the annual global carbonate sediment flux, a quantity important to models of global carbonate production and the global carbon cycle.

Post‐fire thin debris flows: sediment transport and numerical modelling

AbstractThe creation of a hydrophobic layer in the soil during fires in semi‐arid environments inhibits the infiltration of rainfall. This leads to increased rates of runoff and associated sediment transport. When the hydrophobic layer is deposited beneath the soil surface, a perched water table develops which may cause thin (1–2 cm) hillslope failures that are distinguishable from features caused by rilling and sheetflow. Evidence for these failures was observed after a fire near Santa Barbara, California. The amount of sediment eroded from some hillslopes was substantial, with 290 kg of sediment per metre width of hillslope delivered to the valley floor. The mechanics of these failures are examined with a numerical model that incorporates a stability analysis with subsurface flow routing along a typical hillslope profile. The model correctly predicts the location of the failures as well as the rainfall amount necessary to trigger them. Copyright © 2003 John Wiley & Sons, Ltd.

Sediment Movement and Filtration in a Riparian Meadow following Cattle Use

Improper livestock grazing practices in western U.S. riparian areas may reduce the nutrient and pollutant removal function of riparian communities, resulting in degradation of surface water quality. Short duration-high intensity cattle use in 3 x 10 m plots was evaluated in a montane riparian meadow in northern Colorado to quantify livestock effects on sediment movement and filtration under simulated rainfall (approximately equal to 100 mm hour(-1)) plus overland flow (approximately equal to 25 mm hour(-1)) conditions. Four treatments: 1) control, 2) mowed to 10 cm stubble height, 3) trampled by cattle, and 4) cattle grazed plus trampled (grazed) were evaluated. Sixty kg of sediment was introduced to overland flow in each plot. Sediment movement was evaluated using sediment traps positioned in microchannels and on vegetation islands at 5 distances downslope from the upper end of the plots and by sediment front advancement. Most sediment deposition occurred within the first meter downslope from application. About 90% of the applied sediment was filtered from runoff within 10 m in the control and mowed treatments, while approximately 84 and 77% of the applied sediment was trapped in the trampled and grazed treatment plots, respectively. The primary variables that influenced sediment filtration were stem density and surface random roughness. Stem density was the most influential variable that affected sediment filtration. Cattle grazing reduced the stem density by 40%. Monitoring of stem density should aid land managers in regulating cattle use of riparian communities and facilitate the protection of surface water quality from sediment in overland flow. DOI:10.2458/azu_jrm_v55i4_mceldowney

Sediment movement and filtration in a riparian meadow following cattle use

Improper livestock grazing practices in western U.S. riparian areas may reduce the nutrient and pollutant removal function of riparian communities, resulting in degradation of surface water quality. Short duration-high intensity cattle use in 3 x 10 m plots was evaluated in a montane riparian meadow in northern Colorado to quantify livestock effects on sediment movement and filtration under simulated rainfall (approximately equal to 100 mm hour(-1)) plus overland flow (approximately equal to 25 mm hour(-1)) conditions. Four treatments: 1) control, 2) mowed to 10 cm stubble height, 3) trampled by cattle, and 4) cattle grazed plus trampled (grazed) were evaluated. Sixty kg of sediment was introduced to overland flow in each plot. Sediment movement was evaluated using sediment traps positioned in microchannels and on vegetation islands at 5 distances downslope from the upper end of the plots and by sediment front advancement. Most sediment deposition occurred within the first meter downslope from application. About 90% of the applied sediment was filtered from runoff within 10 m in the control and mowed treatments, while approximately 84 and 77% of the applied sediment was trapped in the trampled and grazed treatment plots, respectively. The primary variables that influenced sediment filtration were stem density and surface random roughness. Stem density was the most influential variable that affected sediment filtration. Cattle grazing reduced the stem density by 40%. Monitoring of stem density should aid land managers in regulating cattle use of riparian communities and facilitate the protection of surface water quality from sediment in overland flow.

Associated fauna of Sabellaria alveolata colonies on the central coast of Portugal

This study deals with the associated fauna of Sabellaria alveolata (Annelida: Polychaeta) colonies on the central coast of Portugal. Samples were collected on two shores, Magoito and Avencas and a total of 137 taxa were found on both shores. In qualitative terms, χ2-test shows significant differences between shores. In Magoito crustaceans are the most abundant associated fauna while in Avencas polychaetes are the most abundant. Relative biomass and abundance per kg of sediment is much higher in eroded colonies than in developed ones and diversity seems to increase with reduced wave action.

SPATIAL AND TEMPORAL DISTRIBUTION OF SEDIMENT CONCENTRATION AND PARTICLE SIZE DISTRIBUTION IN A FIELD SCALE SEDIMENTATION BASIN

The degree of uniform sediment concentration and particle size distribution at 13 spatially distributedsampling points in a 155-m3 sedimentation basin during the inflow period of six identical 100-m3 inflow hydrographscontaining 454 kg of sediment was evaluated. The six events represented the sediment concentration and particle sizedistributions in three replications each of an unlined and a lined (no re-suspension) basin. Sediment concentrationsobserved at all sampling locations and up to 12 sampling times showed no significant difference during either the lined orunlined treatments. These results strongly confirm that sediment concentrations were consistent with those expected in asingle, completely mixed reactor. The unlined treatment, however, yielded sediment concentrations 36% higher and thesuspended particle sizes averaged 3.7 m smaller than during the lined treatment. The increased mass of smallerparticles suspended during the unlined treatment was attributed to an increased amount of re-suspended sediment.

Sediment Filtration in a Montane Riparian Zone under Simulated Rainfall

A 2 year study was conducted to evaluate the effectiveness of riparian vegetation to filter sediment from overland water flow. Three vegetation height treatments: clipped to the soil surface, clipped to a 10 cm height, and undisturbed were evaluated in 2 montane riparian vegetation communities (grass and sedge) in northern Colorado. Water was sprayed on 2 macro-plots (3 m X 10 m) and 2 micro-plots (0.6 m X 2 m) simultaneously at a rate of 60 mm hr-1 with a rotating boom rainfall simulator. Overland flow containing sediment was introduced at the upper end of the plots at a rate of 25 mm hr-1 to simulate runoff and sediment transport from an upland area. Two sediment sources were used, a sandy loam soil and a ground silica sediment (loam). Thirty kg of sediment were added to each macro-plot and 1.2 kg of sediment were introduced to each micro-plot (10 Mg ha-1). Sediment yields, at the downslope end of the plot, were greater when the finer silica sediment was introduced into overland flow as compared with sediment derived from the sandy loam soil. As expected the small micro-plots yielded more sediment and were often more sensitive to community and treatment differences than larger plots. We believe this resulted from the shorter travel distance. However, sediment filtration treatment effects were usually similar for both plot sizes. Sediment yields, measured at the outlet of the plots, did not decrease, or increase, as vegetation heights increased. Accurate prediction of sediment filtration from shallow flow in riparian zones required consideration of a combination of vegetation and soil surface characteristics.

Sediment Movement through Riparian Vegetation under Simulated Rainfall and Overland Flow

A 2-year rainfall simulation study was conducted to evaluate the effectiveness of riparian vegetation to reduce sediment movement. Three vegetation height treatments [clipped to the soil surface, 10 cm height, and undisturbed (unclipped)] were evaluated in 2 montane riparian vegetation communities in northern Colorado. One community was a tufted hairgrass (Deschampsia caespitosa (L.) Beauv.), cinquefoil (Potentilla gracilis Dougl. ex Hook), Kentucky bluegrass (Poa pratensis L.), and sedge (Carex spp.) association. The other community was dominated by beaked sedge (Carex rostrata Stokes) and water sedge (Carex aquatilis Wahl.). Water was sprayed on plots (3 m X 10 cm) at a rate of 60 mm hour-1 with a rainfall simulator, while overland flow containing sediment was introduced at the upper end of the plots at a rate of 25 mm hour-1. Two sediment sources were evaluated. In the first year's studies the sediment was derived from an upland soil. The second year a fine silica sediment was used. Thirty kg of sediment was added to each plot. The first of 2 experiments was concerned with movement of sand particles greater than 200 micrometers. The second experiment was designed to evaluate the quantity of 5 particle size classes (2-10, 10-30, 30-50, 50-100, and 100-200 micrometers) contained in sediment traps at 60, 120, and 180 cm downslope from the upslope border of the simulator plots. Results of the first experiment showed a significant increase in sand movement downslope when vegetation was clipped to the soil surface compared with undisturbed vegetation. In the second experiment, most significant differences in movement for finer particles occurred in the 2-10 micrometers and 10-30 micrometers particle ranges. A smaller percentage of particles in the 2-10 micrometers range was present in sediment traps at all 3 distances downslope when vegetation was clipped to the soil surface, as these smaller particles stayed in suspension. Increased vegetation height resulted in a significantly smaller percentage of the 10-30 micrometers particle size range present at 120 cm distance. This study showed that additional variables (% surface vegetation cover, aboveground biomass, % shrubs, surface roughness coefficient, soil texture of introduced sediment, % bare ground, distance downslope, vegetation density, grass spp., and sedge spp.), besides vegetation height, influenced sediment movement. Land managers should understand that when they manage ecosystems for a single factor, such as vegetation height, they cannot address complex issues such as sediment particle detachment, movement and filtration.

Detrital sediment fluxes from continents to oceans

Detrital sediment is carried from land to the sea by three agents, rivers, glaciers, and winds. The shoreline is an arbitrary boundary within the detrital sediment transport system, which extends from a site of origin across areas of temporary storage to a site of long-term deposition. The most important of the agents moving sediment across the land is river transport, estimated to be in the order of 20×10 12 kg of sediment annually at present. Analysis of drainage basins indicates that relief and runoff are the most important factors in determining the sediment load of rivers. The competence of rivers to transport sediment is governed by the volume flow, gradient, and the sediment load itself. Today, most large rivers are fed by snowmelt in highland areas, runoff from rainfall in the drainage basin, and groundwater inflow. Along the river course, water is lost to evaporation and groundwater infiltration. River courses can often be divided into two segments, a degradational section in which the gradient is relatively steep and little temporary storage of sediment takes place, and an aggradational section where the gradient is sharply reduced through meandering, and where large-scale temporary sediment storage forms a flood plain. Lakes trap sediment inland and prevent its transport to the sea. Today, many high and mid-latitude rivers are interrupted by lakes of glacial origin. There are also some large areas of internal drainage that deliver no sediment to the sea. The load carried by rivers has been markedly altered by human activity, and may have doubled over the past few thousand years, only to be reduced in the past century by the widespread construction of dams. The ancient use of fire in hunting and its subsequent use in clearing land has increased erosion. Extensive deforestation and cultivation processes have also increased the sediment supply. Dam construction is a relatively new factor and affects the sediment transport system by trapping sediment before it can reach the sea. The resulting lower sediment supply from rivers is, at least in part, compensated by increased coastal erosion. Glacial erosion is difficult to estimate. There is an ongoing controversy whether ice sheets are effective erosive agents or not. Estimates of the present global flux of glacial detritus range from 0.8–50×10 12 kg annually, with the lower value most probable. The dust flux is in the order of 0.5 to 0.9×10 12 kg annually, but may vary greatly with time.

Currents and Sediment Transport in Mangrove Forests

A field study of the tidal currents, cohesive sediment dynamics and transport of organic carbon in a highly vegetated mangrove swamp was carried out at Middle Creek, Cairns, Australia. The interaction of tidal currents and the vegetation generated jets, eddies and zones of stagnant waters which were numerically modelled. A high value of the Manning friction coefficient ( n=0·1) was derived by the dense vegetation. About 80% of the suspended sediment brought in from coastal waters at spring flood tide was trapped in the mangroves, corresponding to about 10–12 kg of sediment m −1creek length/spring tide, resulting in a rise of the substrate by about 0·1 cm year −1. The selective trapping of clay was caused by flocculation of the finer particles in the mangroves. There was an indication of a slight inwelling of organic carbon. Creek water was readily differentiated from mangrove water by large differences in the molecular weight distribution of the dissolved organic carbon.

EXPERIMENTAL EVALUATION OF SEDIMENTATION BASIN PERFORMANCE FOR ALTERNATIVE DEWATERING SYSTEMS

The effectiveness of four sediment removal/water control treatments, each designed to dewater the 155-m3 sedimentation basin in 24 h, was evaluated using 100-m3 inflow hydrographs (35-mm, 2-yr runoff events) from a 0.4-ha denuded construction site containing 454 kg of sediment. The treatments were a perforated riser alone that discharged 26.1 kg of sediment and had an overall sediment retention efficiency of 94.3%; two internal barriers designed to trisect the basin’s volume with a perforated riser, significantly reduced the sediment loss below that of the perforated riser alone to 20.4 kg; a skimmer alone discharged the least total sediment at only 14.3 kg; and trisecting the basin with barriers, with the skimmer, did not improve the capture efficiency of the basin over that of the skimmer alone. All treatments removed 100% of soil particles and aggregates larger than 75 im. The basin sediment was completely mixed during the entire inflow/dewatering event and the effluent particle size distribution was the same as that observed for the influent sediment smaller than 75 im. Particle sizes retained between 0.1 and 75 im ranged from 77 to 100% with the poorest retention in the 6 to 12 im range.

INFLUENCE OF PRINCIPAL SPILLWAY GEOMETRY AND PERMANENT POOL DEPTH ON SEDIMENT RETENTION OF SEDIMENTATION BASINS

Sediment retained in a 197-m3 sedimentation basin during 12, two-year storms with identical 100-m3 inflow hydrographs and 454 kg sedigraphs was measured. Sediment discharged through the perforated riser and single-orifice principal spillways was similar at 23.1 kg. Of the average of 23.1 kg of sediment discharged during each event, 3.0 kg was resuspended from previously deposited sediment, 9.1 kg originated from the basin floor and sides, and 11.0 kg originated from the soil injected during that event. Sediment discharge averaged 13.4 kg for the 0.46-m deep permanent pool and 24.0 kg for the 0.15-m deep permanent pool.

Procedures for Sampling Deep Subsurface Microbial Communities in Unconsolidated Sediments

AbstractA corehole sampling project utilizing a wireline coring system provided sediment samples for microbiological characterization from deep unconsolidated sediments. Sampling tools were developed or modified to minimize contamination during sample acquisition and to facilitate stringent decontamination requirements. Quality assurance procedures, including the use of tracers, were implemented to minimize and quantify contamination from drilling hardware, drilling fluids and sample processing. Tracers included microspheres, potassium bromide, rhodamine dye, and perfluorocarbons, which enabled the detection and measurement of 1mg of drilling fluid per kg of sediment. In addition, sample processing was performed on‐site in an anaerobic chamber to prevent exposure of the subsurface materials to atmospheric oxygen concentrations. Sediment samples were then disbursed to investigators at National Laboratories and universities funded through the Department of Energy Subsurface Science Microbiology Program for microbiological characterization. Results of these efforts demonstrated that representative subsurface samples were collected and disbursed.