Rhizon Sampling of Pore Waters on Scientific Drilling Expeditions: An Example from the IODP Expedition 302, Arctic Coring Expedition (ACEX)

Dickens, Gerald R.; Kölling, Martin; Smith, David C.; Schnieders, Luzie

doi:10.2204/iodp.sd.4.08.2007

Cited by 41 publications

(36 citation statements)

References 8 publications

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“…Two experiments conducted during the SWERUS-C3 Leg 2 expedition using the Rhizons suggest that part of the problem concerns the timing and location of sampling (Supplement). Notably, however, as clearly documented in previous works (SeebergElverfeldt et al, 2005;Dickens et al, 2007;Pohlman et al, 2008), Rhizon sampling can lead to smooth concentration profiles for multiple dissolved species, including alkalinity (Figs. 4-8).…”

Section: Fidelity Of Rhizon Pore Water Measurementssupporting

confidence: 61%

“…Researchers have employed multiple methods to extract pore waters from marine sediments over the last few decades, but the Rhizon technique remains relatively novel (e.g., SeebergElverfeldt et al, 2005;Dickens et al, 2007;Pohlman et al, 2008). Several studies have questioned the accuracy and precision of analyses obtained through this approach (e.g., Schrum et al, 2012;Miller et al, 2014).…”

Section: Fidelity Of Rhizon Pore Water Measurementsmentioning

confidence: 99%

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Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

et al. 2017

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Abstract. Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH 4 ) in sediments as gas hydrate and free gas. Although release of this CH 4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) expedition. The cores come from depth transects across the slope and rise extending between the Mendeleev and the Lomonosov ridges, north of Wrangel Island and the New Siberian Islands, respectively. Upward CH 4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO 2− 4 ), alkalinity, and the δ 13 C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143 • E longitude. In the upper 8 m of these cores, downward SO 2− 4 flux never exceeds 6.2 mol m −2 kyr −1 , the upward alkalinity flux never exceeds 6.8 mol m −2 kyr −1 , and δ 13 C composition of DIC (δ 13 C-DIC) only moderately decreases with depth (−3.6 ‰ m −1 on average). Moreover, upon addition of Zn acetate to pore water samples, ZnS did not precipitate, indicating a lack of dissolved H 2 S. Phosphate, ammonium, and metal profiles reveal that metal oxide reduction by organic carbon dominates the geochemical environment and supports very low organic carbon turnover rates. A single core on the Lomonosov Ridge differs, as diffusive fluxes for SO 2− 4 and alkalinity were 13.9 and 11.3 mol m −2 kyr −1 , respectively, the δ 13 C-DIC gradient was 5.6 ‰ m −1 , and Mn 2+ reduction terminated within 1.3 m of the seafloor. These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH 4 , including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on assumption.

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Section: Fidelity Of Rhizon Pore Water Measurementssupporting

confidence: 61%

Section: Fidelity Of Rhizon Pore Water Measurementsmentioning

confidence: 99%

Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

et al. 2017

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“…Rhizons have been used on several deep ocean drilling expeditions, but there is little documentation on how these samplers behave with respect to traditional squeezing methods, in regard to their effect on the concentration and isotopic content of the pore fluid. Dickens et al [2007] compared the manganese and ammonium concentrations in samples recovered with Rhizons versus those recovered through squeezing, concluding that Rhizons had no deleterious effect on the samples, but their study only compared a few overlapping Rhizon and squeeze samples (six points). Schrum et al [2012] made a more comprehensive study of alkalinity, dissolved inorganic carbon (DIC), ammonium, sulfate, and chloride.…”

Section: Introductionmentioning

confidence: 99%

Rhizon sampler alteration of deep ocean sediment interstitial water samples, as indicated by chloride concentration and oxygen and hydrogen isotopes

Miller

Adkins

Hodell

2014

Geochem Geophys Geosyst

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Despite their potential to inform past ocean salinity, d18 O, and temperature, high-resolution depth profiles of interstitial water chloride concentration and hydrogen and oxygen isotopes exist in very few locations. One of the primary limitations to the recovery of these depth profiles is that traditional interstitial water sampling requires 5-10 cm whole rounds of the sediment core, which has the potential to interfere with stratigraphic continuity. The Rhizon sampler, a nondestructive tool developed for terrestrial sediment interstitial water extraction, has been proposed for efficient and nondestructive sampling of ocean sediment pore waters. However, there exists little documentation on the reliability and performance of Rhizon samplers in deep ocean sediments, particularly in regard to their effect on chloride concentration and oxygen and hydrogen isotopic measurements. We perform an intercomparison of chloride concentration and oxygen and hydrogen isotopic composition in samples taken using traditional squeezing versus those taken with Rhizon samplers. We find that samples taken with Rhizons have positive biases in both chloride concentration and stable isotopic ratios relative to those taken by squeezing water from sediments in a hydraulic press. The measured offsets between Rhizon and squeeze samples are consistent with a combination of absorption by and diffusive fractionation through the hydrophilic membrane of the Rhizon sampler. These results suggest caution is needed when using Rhizons for sampling interstitial waters in any research of processes that leave a small signal-to-noise ratio in dissolved concentrations or isotope ratios.

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“…Pore water was collected through 0.15 μm mesh 5 cm long CSS-F Rhizon samplers (Rhizosphere Research Products, Netherlands) into precleaned 20 mL plastic syringes following established protocols (Dickens et al, 2007;Seeberg-Elverfeldt et al, 2005). Table T9 summarizes the samples collected for pore water analysis.…”

Section: Iodp Proceedingsmentioning

confidence: 99%

Expedition 357 methods

Früh-Green¹,

Orcutt²,

Green³

et al. 2017

Proceedings of the International Ocean Discovery Program

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Rhizon Sampling of Pore Waters on Scientific Drilling Expeditions: An Example from the IODP Expedition 302, Arctic Coring Expedition (ACEX)

Cited by 41 publications

References 8 publications

Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

Rhizon sampler alteration of deep ocean sediment interstitial water samples, as indicated by chloride concentration and oxygen and hydrogen isotopes

Expedition 357 methods

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