Submarine mud volcanoes as a source of chromophoric dissolved organic matter to the deep waters of the Gulf of Cádiz

Amaral, Valentina; Romera‐Castillo, Cristina; Forja, Jesús M.

doi:10.1038/s41598-021-82632-3

Cited by 38 publications

(5 citation statements)

References 60 publications

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“…Meanwhile, low HIX values, large fraction of protein-like components (46-80%) and high BIX values also indicate intensified production of relatively labile FDOM with lower degradation degree associated with AOM at the seep cores compared to the reference core where sedimentary DOM is mostly produced by POCSR (Figure 4). Similar results have been reported at the mud volcanoes in the Gulf of Cádiz where the protein-like components accounted for ∼70% of the total FDOM (Amaral et al, 2021).…”

Section: Enhanced Production Of Labile Dissolved Organic Carbon In the Seep Sedimentssupporting

confidence: 88%

“…In addition to POC mineralization, DOC production in seepimpacted sediments is closely associated with the anaerobic oxidation of methane (AOM; Pohlman et al, 2011). As a result, significantly higher DOC concentrations have been observed in seep sediments compared to non-seep deep sea sediments (Hung et al, 2016;Amaral et al, 2021). Valentine et al (2005) found that the proportion of methane-derived DOC increases with enhanced AOM rates and microbial activity in the cold seep sediments.…”

Section: Introductionmentioning

confidence: 99%

“…Optical property provides important insights into the source, composition, and reactivity of dissolved organic matter (DOM; Burdige et al, 2004;Coble, 2007;Dittmar and Stubbins, 2014;Chen et al, 2016;Wagner et al, 2020). Microbial metabolism sustained by deeply-sourced methane-rich fluids via mud volcanism has been documented to significantly contribute to the production of fluorescence dissolved organic matter (FDOM), ∼70% of which was characterized by labile, proteinlike fluorescence components (Amaral et al, 2021). Apart from the microbe-derived FDOM, thermogenically altered FDOM transported from the deep subsurface has also been detected in mud volcano pore fluids (Brogi et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Production of Labile Protein-Like Dissolved Organic Carbon Associated With Anaerobic Methane Oxidization in the Haima Cold Seeps, South China Sea

Luo

et al. 2021

Front. Mar. Sci.

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Cold seeps where methane-rich fluids escape from the seafloor generally support enormous biomass of chemosynthetic organisms and associated fauna. In addition to transporting a great amount of methane toward the seafloor, cold seeps also contribute to the aged, dissolved organic carbon (DOC) pool in the deep ocean. Here, two sediment cores from the “Haima cold seeps,” northern South China Sea and a nearby reference core were analyzed for pore-water sulfate and DOC concentrations, δ13C of DOC, and optical properties of dissolved organic matter (DOM). High DOC concentrations (0.9–3.7 mM) accompanied by extremely low δ13C values (−43.9 to −76.2‰) suggest the conversion of methane into sedimentary DOC pool in the seep sediments. Parallel factor analysis (PARAFAC) of the fluorescence excitation-emission matrices shows higher fluorescent intensities of labile protein-like components (C2 and C4) and lower fluorescent intensities of refractory humic-like components (C1 and C3) in the seep cores compared to the reference core. The intensity of C2 is positively correlated with DOC concentrations and δ13C-DOC in the seep sediments, suggesting that the labile protein-like DOM was produced by the anaerobic oxidation of methane (AOM). Moreover, low humification index (HIX) and high biological index (BIX) values also indicate intensified production of relatively labile DOM with lower degradation degree in the seep cores compared to the reference core. Hence, we highlight that methane-derived DOC may serve as important carbon and energy sources for heterotrophic microbial communities due to its relatively labile nature.

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Section: Enhanced Production Of Labile Dissolved Organic Carbon In the Seep Sedimentssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Production of Labile Protein-Like Dissolved Organic Carbon Associated With Anaerobic Methane Oxidization in the Haima Cold Seeps, South China Sea

Luo

et al. 2021

Front. Mar. Sci.

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“…The venting of SMV transport not only thermogenic methane but also DOC into the ocean (Hung et al, 2016;Brogi et al, 2019;Chen et al, 2020;Amaral et al, 2021). Our simulations shows that the benthic DOC flux is in the range of 0.04-3.33 mmol C m −2 yr −1 (Table 4), which is much lower than that in the previous study (57-90 mmol C m −2 yr −1 ; Hung et al, 2016).…”

Section: Benthic Doc Flux At Ty1mentioning

confidence: 99%

Controlling factors on patterns of dissolved organic carbon and volatile fatty acids in a submarine mud volcano offshore southwestern Taiwan

Chen¹,

Yang²,

Liou³

et al. 2023

Front. Earth Sci.

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Dissolved organic carbon (DOC) and volatile fatty acids (VFAs) play key roles in the carbon cycling of marine sediment. Both microbially or thermally activated cracking of organic matter often produces high quantities of DOC and VFAs. To uncover the distribution pattern of DOC and VFAs in sediments under both impacts, a submarine mud volcano (SMV), was chosen to denote a model system that could witness how microbial activities react under the mixing of seawater and deeply-sourced fluids in a subsurface environment. We examined the concentration profiles of DOC and several VFAs (lactate, formate, acetate, propionate, and butyrate) in pore water, covering both sulfate reduction and methanogenesis zones, and further numerically modeled six porewater species (DOC, bromide, calcium, magnesium, ammonium, and total alkalinity) to quantify their fluxes from depth as well as the rates of in-situ microbial processes. Apparently, bulk DOC concentrations fluctuated with depths, probably primarily controlled by in situ microbial processes. Lactate was detectable in some samples, while propionate and butyrate were under detection limit. Acetate and formate concentrations were consistently and uniformly low throughout all biogeochemical zones, with a slightly increasing trend with depth at the center of the SMV, suggesting active utilization and turnover by the terminal steps of organic matter mineralization. The numerical modeling suggests that most DOC patterns were primarily influenced by in-situ organic matter degradation, while the impact of upward migrating fluid become more significant at center sites. The calculation of the Gibbs energy of metabolic redox reactions reveals that acetoclastic sulfate reduction yields the highest energy throughout sediment columns and may co-exist with methanogenesis below sulfate reduction zone. In contrast, acetoclastic methanogenesis yields higher energy within sulfate reduction zone than below that region, suggesting it is thermodynamically feasible to co-occur with sulfate reduction in dynamic SMV environments.

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“…One of the main abiotic factors in uencing its composition and structure is water salinity. While a lot of studies have explored spatial and temporal variations in DOM content and composition in estuarine waters (Bianchi 2011;Walker et al 2013;Amaral et al 2021), only a limited number of studies have directly assessed the transformation of soil DOM under the in uence of salinity (I. Esteves et al 1999; Gao et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Direct Salinity Effect on Absorbance and Flourescence of Chernozem Water-Extractable Organic Matter

Холодов

Данченко

Ziganshina

et al. 2023

Preprint

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Soil-derived dissolved organic matter (DOM) has a significant impact on aquatic ecosystems. Identifying the fluorescence signatures of DOM from different soils in river and sea waters can provide valuable insights into its migration patterns. This makes crucial the assessment of pH, salinity, and other parameters contribution to the variability of DOM fluorescence. Present study investigates the changes of DOM of typical Chernozems under varying salinity using UV-visible absorbance and excitation–emission matrices of fluorescence spectroscopy coupled with parallel factor analysis (EEMs-PARAFAC). Water-extractable organic matter (WEOM) as a proxy for DOM was isolated from soils of two field experiment plots with contrasting land uses: long-term bare fallow (LTBF) and annually mowed steppe (Steppe). The extracts were incubated in the dark with varying NaCl concentrations and examined. Steppe WEOM exhibited high structural and aggregation resistance to salinity changes, while significant changes in optical parameters and loads of PARAFAC components were observed for LTBF WEOM. The remarkable stability of the Steppe WEOM can be attributed to its chemical diversity. Two distinct and sufficiently stable humic-like PARAFAC components have the potential to serve as markers of Chernozem DOM. The findings contribute to the limited existing knowledge on the direct influence of salinity on the transformation of specific soil types DOM.

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Submarine mud volcanoes as a source of chromophoric dissolved organic matter to the deep waters of the Gulf of Cádiz

Cited by 38 publications

References 60 publications

Production of Labile Protein-Like Dissolved Organic Carbon Associated With Anaerobic Methane Oxidization in the Haima Cold Seeps, South China Sea

Production of Labile Protein-Like Dissolved Organic Carbon Associated With Anaerobic Methane Oxidization in the Haima Cold Seeps, South China Sea

Controlling factors on patterns of dissolved organic carbon and volatile fatty acids in a submarine mud volcano offshore southwestern Taiwan

Direct Salinity Effect on Absorbance and Flourescence of Chernozem Water-Extractable Organic Matter

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