A diagnostic GDGT signature for the impact of hydrothermal activity on surface deposits at the Southwest Indian Ridge

Pan, Anyang; Qinye, Yang; Zhou, Huaiyang; Ji, Fuwu; Wang, Hu; Pancost, Richard D.

doi:10.1016/j.orggeochem.2016.07.001

Cited by 26 publications

(33 citation statements)

References 116 publications

(176 reference statements)

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“…It was found that there were no significant differences in microbial compositions between the hydrothermal plume samples and the ambient seawater (Li et al, ). Nevertheless, microorganisms (including bacterial and archaea) such as Fe, Mn, S oxidizers and reducers, and membrane lipids were abundant in the low‐temperature diffuse environment (Li et al, ; Pan et al, ; Peng et al, ). Therefore, organic matter from the nearby diffuse flow might be the most likely source of the ligands in Longqi hydrothermal plumes.…”

Section: Resultsmentioning

confidence: 99%

“…The possible sources include diffuse flow adjacent to the high-temperature vents and/or in situ biological activities. Since the Longqi hydrothermal field was found in 2007 (Tao et al, 2012), various studies, including the physical, chemical, and biological characteristics of the hydrothermal fluids, plumes, and the diffuse flow, have been carried out (Ji et al, 2017;Li et al, 2014Li et al, , 2016Liao et al, 2016;Pan et al, 2016;Peng et al, 2011;Tao et al, 2012Tao et al, , 2014Wang et al, 2012Wang et al, , 2015. It was found that there were no significant differences in microbial compositions between the hydrothermal plume samples and the ambient seawater (Li et al, 2016).…”

Section: The Fe Speciationmentioning

confidence: 99%

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The Size Fractionation and Speciation of Iron in the Longqi Hydrothermal Plumes on the Southwest Indian Ridge

et al. 2019

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The distribution and composition of Fe in hydrothermal plumes are crucial for understanding the contribution of hydrothermal venting to the oceanic Fe inventory. In this study, we conduct the first complete investigation of the size fractions of Fe and Fe‐binding ligands in the Longqi hydrothermal plumes on the Southwest Indian Ridge, combining the approaches of the size partitioning and reverse titration‐competitive ligand exchange‐adsorptive cathodic stripping voltammetry. Concentrations of all the Fe fractions were very high in the plume samples, and dissolved Fe (<0.2 μm) constituted a significant portion (48.7 ± 7.9%) of total Fe, which might be related to the existence of colloidal Fe oxyhydroxides and sulfides, as well as organic Fe complexes. Dissolved Fe consisted of colloidal Fe (10 kDa to 0.2 μm, ~70.2%) and soluble Fe (<10 kDa, ~29.8%). Colloidal Fe mainly contained Fe oxyhydroxides and sulfides (86.4 ± 6.2%), while most of the soluble Fe were organic Fe complexes (65.7 ± 5.4%). Fe speciation analyses showed that dissolved ligand concentrations were high in the hydrothermal plumes but were significantly lower than the dissolved Fe concentrations. Inferring from previous studies in the Longqi hydrothermal field, the ligands were most likely derived from the diffuse flow adjacent to the hydrothermal vents. The conditional stability constants (logK′FeL) of dissolved FeL (20.4 ± 0.5) were slightly higher than those of soluble FeL (19.6 ± 0.4), although they were not statistically different. Based on the ligands' size partitioning, the soluble ligands stabilized ~8.8 ± 3.8% of the hydrothermal Fe, which is over 2 times that of the colloidal ligands, ~4.0 ± 1.8%.

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Section: Resultsmentioning

confidence: 99%

Section: The Fe Speciationmentioning

confidence: 99%

The Size Fractionation and Speciation of Iron in the Longqi Hydrothermal Plumes on the Southwest Indian Ridge

et al. 2019

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“…(b) Relative contribution of sum of brGDGT‐I, brGDGT‐II, and brGDGT‐III. The sources of data are as follows: Schouten et al () and Weijers et al () for open marine sediments; Tierney et al () for lake sediments; Zell et al () for coastal sediments; Jaeschke et al () for black chimney; Pan et al () for low‐temperature hydrothermal deposits; Weijers et al () for soils; He et al () for hot springs; and Liu et al () for seawater column. GDGT = glycerol dialkyl glycerol tetraether.…”

Section: Discussionmentioning

confidence: 99%

Distributions and Sources of Glycerol Dialkyl Glycerol Tetraethers in Sediment Cores From the Mariana Subduction Zone

Peng

et al. 2019

JGR Biogeosciences

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Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitously found in marine sediments.However, their presence, distributions, and sources in the subduction zone are not fully understood. We investigated isoprenoidal GDGTs (isoGDGTs) and branched GDGTs (brGDGTs) in two sediment cores from the southern and northern subduction plates of Mariana Trench, respectively. IsoGDGTs and brGDGTs exhibited covariation in most sediment samples, and total GDGT concentrations reached a maximum at the subsurface sediment depth~10 cm. Concentrations of isoGDGTs and brGDGTs were clearly elevated at depths of~10 and~45 cm. These indicated that microbial activities potentially influenced the production of the specific membrane lipids of archaea and bacteria. We found that the branched and isoprenoid tetraether index and R b/i values increased with depth profiles of the Mariana subduction zone, suggesting that deeper sediments likely hosted more brGDGT-producing bacteria than crenarchaeol-producing archaea. The extremely high abundance of cyclopentyl rings in brGDGTs was determined in subsurface sediments. We further proposed that most of the brGDGTs in sediments were produced in situ in the Mariana subduction zone. This study highlights that the extremophilic microbial communities of the Mariana subduction zone may represent a significant component of the global carbon cycle.

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“…There are also relatively few studies on the effects of hydrothermal activity on the surrounding environment, especially the metalliferous sediments (Pan et al, 2016) formed via a combination of sulfide mass wasting and debris flow, low-temperature fluid flow and mineralization, or plume formation, dispersal and fallout (Dias et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…These three distinct surface deposits provide an opportunity to explore the potential effects of hydrothermal activity on the surrounding sediments. Our previous study examining the distribution of glycerol dialkyl (and monoalkyl) glycerol tetraether (GDGT and GMGT) archaeal membrane lipids (Pan et al, 2016) clearly showed that GDGT distributions in normal marine sediments, near-field metalliferous sediments and low-temperature hydrothermal deposits vary significantly, whereas the far-field metalliferous sediments have the same GDGT distribution as that of the background sediments.…”

Section: Introductionmentioning

confidence: 99%

Geochemical impacts of hydrothermal activity on surface deposits at the Southwest Indian Ridge

Pan

Qinye

Zhou

et al. 2018

Deep Sea Research Part I: Oceanographic Research Papers

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Submarine hydrothermal circulation has attracted much scientific interest since seafloor hydrothermal activity was first observed in the 1970s; an area of particular interest is the impact of exported inorganic and organic materials from hydrothermal vent systems into the open ocean. In 2007, the first active hydrothermal vent field, with vent fluid temperatures up to 379 °C, was discovered at the ultraslow spreading Southwest Indian Ridge (SWIR), where active vents are much less abundant than fast spreading ridges, and the effect of hydrothermal extrusion on surface sediments is not fully understood. To explore how geochemical proxy signatures respond to hydrothermal activity, we investigated the distributions of elements, minerals and lipids in surficial normal marine sediments, metalliferous sediments and low-temperature hydrothermal deposits collected from the SWIR. The results showed different effects of hydrothermal activity on the surface deposits. The normal marine sediments were predominantly calcium carbonate characterized by >42% CaO and >90% calcite, with a significant autochthonous marine contribution to organic matter (OM) and a predominance of lower molecular weight alkanols and fatty acids; they were uninfluenced by hydrothermal activity but received some terrigenous input represented by abundant high molecular weight n-alkanes with an odd-over-even predominance. The near-field metalliferous sediments and hydrothermal deposits were very different. Some near-field metalliferous sediments were influenced by low-temperature hydrothermal activity, and their distributions of elements and minerals were similar to those of hydrothermal deposits, which were characterized by abundant Fe/Si and opal/nontronite. Other near-field metalliferous sediments were evidently influenced by mixing of high-temperature hydrothermal sulfides typically containing abundant Cu/Zn. With respect to the organic matter assemblages, near-field deposits contained little evidence for thermal maturation of organic matter and all were characterized by a strong microbial signature, including hopanoids, isoprenoidal and non-isoprenoidal dialkyl glycerol ether lipids, and low molecular weight n-alkanes with an even carbon number predominance. The far-field metalliferous sediments, despite the influence of non-buoyant plumes and slightly higher concentrations of hydrothermal-derived metals (e.g., Fe, Cu and Zn), had the same distribution of organic lipids and major mineral composition (>90% calcite) as did normal marine sediments. Thus, the influence of non-buoyant plume inputs appears to have been minimal possibly due to the dilution of in situ microorganisms by normal marine organisms in sediment and seawater. Furthermore, these characteristics indicate inorganic indices based on abundant metal elements derived from the hydrothermal systems (such as Fe/Cu/Zn content, ∑REE/Fe, the ternary diagram of Fe, Cu×100 and Ca) are more sensitive, serving as better proxies than organic matter assemblages to differentiate the effects of diverse h...

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A diagnostic GDGT signature for the impact of hydrothermal activity on surface deposits at the Southwest Indian Ridge

Abstract: The impact of hydrothermal activity on wider ocean geochemistry and microbial ecology

Cited by 26 publications

References 116 publications

The Size Fractionation and Speciation of Iron in the Longqi Hydrothermal Plumes on the Southwest Indian Ridge

The Size Fractionation and Speciation of Iron in the Longqi Hydrothermal Plumes on the Southwest Indian Ridge

Distributions and Sources of Glycerol Dialkyl Glycerol Tetraethers in Sediment Cores From the Mariana Subduction Zone

Geochemical impacts of hydrothermal activity on surface deposits at the Southwest Indian Ridge

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