Seasonal changes in metal and nutrient fluxes across the sediment-water interface in tropical mangrove creeks in the Amazon region

Matos, Christiene R.L.; Berrêdo, José Francisco; Machado, Wilson; Metzger, Édouard; Sanders, Christian J.; Faial, K.C.F.; Cohen, Marcelo Cancela Lisboa

doi:10.1016/j.apgeochem.2022.105217

Cited by 14 publications

(6 citation statements)

References 86 publications

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“…Although limited, existing studies on the sulfidation of pure Fh ,, and influence of coprecipitated OM on Fe(II)-catalyzed Fh transformation , suggest that the anoxic reductive dissolution of ferrihydrite and its pyritization under OM loading depend on various factors, including OM properties, C/Fe ratio, S(-II)/Fe ratio, and pH. , Yet, few studies have systematically evaluated the impact of the abovementioned factors as well as their interactions on the sulfidation of Fh–OM coprecipitates. In porewaters of OM-rich wetland and estuarine sediments, both C/Fe molar ratios (0.2–25.0) , and DS(-II) concentrations (0.023–5.0 mM) − have wide spectrum. Considering the controlling effect of the S(-II)/Fe molar ratio in pure Fh sulfidation, , we therefore hypothesize that the kinetics and mineralogical evolution pathways of Fh–OM sulfidation depend on the interrelated effects of carbon and sulfur loadings.…”

Section: Introductionmentioning

confidence: 99%

Transformations of Ferrihydrite–Extracellular Polymeric Substance Coprecipitates Driven by Dissolved Sulfide: Interrelated Effects of Carbon and Sulfur Loadings

Wang

et al. 2023

Environ. Sci. Technol.

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The association of poorly crystalline iron (hydr)oxides with organic matter (OM), such as extracellular polymeric substances (EPS), exerts a profound effect on Fe and C cycles in soils and sediments, and their behaviors under sulfate-reducing conditions involve complicated mineralogical transformations. However, how different loadings and types of EPS and water chemistry conditions affect the sulfidation still lacks quantitative and systematic investigation. We here synthesized a set of ferrihydrite−organic matter (Fh−OM) coprecipitates with various model compounds for plant and microbial exopolysaccharides (polygalacturonic acids, alginic acid, and xanthan gum) and bacteriogenic EPS (extracted from Bacillus subtilis). Combining wet chemical analysis, X-ray diffraction, and X-ray absorption spectroscopic techniques, we systematically studied the impacts of C and S loadings by tracing the temporal evolution of Fe mineralogy and speciation in aqueous and solid phases. Our results showed that the effect of added OM on sulfidation of Fh−OM coprecipitates is interrelated with the amount of loaded sulfide. Under low sulfide loadings (S(-II)/Fe < 0.5), transformation to goethite and lepidocrocite was the main pathway of ferrihydrite sulfidation, which occurs more strongly at pH 6 compared to that at pH 7.5, and it was promoted and inhibited at low and high C/Fe ratios, respectively. While under high sulfide loadings (S(-II)/Fe > 0.5), the formation of secondary Fe−S minerals such as mackinawite and pyrite dominated ferrihydrite sulfidation, and it was inhibited with increasing C/Fe ratios. Furthermore, all three synthetic EPS proxies unanimously inhibited mineral transformation, while the microbiogenic EPS has a more potent inhibitory effect than synthetic EPS proxies compared at equivalent C/Fe loadings. Collectively, our results suggest that the quantity and chemical characteristics of the associated OM have a strong and nonlinear influence on the extent and pathways of mineralogical transformations of Fh−OM sulfidation.

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Section: Introductionmentioning

confidence: 99%

Transformations of Ferrihydrite–Extracellular Polymeric Substance Coprecipitates Driven by Dissolved Sulfide: Interrelated Effects of Carbon and Sulfur Loadings

Wang

et al. 2023

Environ. Sci. Technol.

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“…Dissolved [Nd] and [Hf] of the Pará River endmember (Sal = 0.3) are 1036 pmol kg -1 and 13.4 pmol kg -1 , respectively, and are thus significantly higher than 502 pmol kg -1 and 12.3 pmol kg -1 of the Amazon River freshwater endmember (Sal = 0.2) (Supplementary Data 1 ). These higher concentrations are likely a result of the overall lower pH of the Pará River pH of 6.2–7.4 (Amazon River: 6.8–7.3) 27 and/or feeding by tributaries from the mangrove forests, which is consistent with high trace metal export from the Amazonian mangrove forest areas 28 – 30 . In addition, parent rock characteristics and floodplain supply may play a role given that elevated REY concentrations in the waters exiting the floodplain have been observed in the Amazon Basin 31 .…”

Section: Resultsmentioning

confidence: 56%

Overlooked riverine contributions of dissolved neodymium and hafnium to the Amazon estuary and oceans

Hathorne

Laukert

2023

Nat Commun

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The Amazon River accounts for 20% of global freshwater runoff and supplies vital trace metals to the Atlantic Ocean. Suspended particles within its plume are thought to partially dissolve, constituting a large potential source of metals, which is, however, not well constrained. Here we used combined neodymium (Nd) and hafnium (Hf) isotopes to disprove the release of Nd and Hf from particles as the cause of the observed dissolved concentration increases and isotopic variability across the plume. Instead, the changes reflect admixture of nearby Pará River freshwater with exceptionally high dissolved Nd and Hf concentrations contributing 45–100% of the riverine fraction to the southern and outer estuary. This result led us to develop an empirical relationship between riverine Nd concentration and pH to revise the global dissolved riverine Nd flux, which accordingly is at least three times higher than commonly used estimates. Future work should focus on contributions of low-pH rivers to global metal fluxes.

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“…The sampling technology for pore-water below the sediment has also been developed. Sediment pore-water usually reflects the trend of seafloor geological changes, which is of great significance for marine geochemical changes and deep-sea resource acquisition (Matos et al, 2022). The main way to obtain pore-water in two ways: One is the non-in-situ pore-water sampling technology, as shown in Figure 9, through the first collection of sediments and then through pressure filtration (Bender et al, 1987), centrifugation (Carignan et al, 1985) or vacuum filtration (Dickens and others, 2007) to separate the porewater.…”

Section: Main Content Of Pore-water Sampling Techniquesmentioning

confidence: 99%

Advances and development in sampling techniques for marine water resources: a comprehensive review

Wang,

Chen,

Guo

et al. 2024

Front. Mar. Sci.

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Marine water resources (including seawater and pore-water) provide important information for understanding the marine environment, studying marine organisms, and developing marine resources. Obtaining high-quality marine water samples is significant to marine scientific research and monitoring of marine resources. Since the 20th century, marine water resources sampling technology has become the key research direction of marine equipment. In order to have a comprehensive understanding of marine water resource sampling technology, promote the development of marine water resource sampling technology, and obtain high-quality marine water samples, this paper summarizes the current development status of the sampling technology of marine water resources from the aspects of research and application. This paper first provides an overview of seawater and pore water sampling techniques. The two sampling technologies are categorized and discussed according to different sampling means, and the advantages of different sampling means are compared. We also found similarities between seawater and pore water sampling means. Then, a comprehensive analysis of existing technologies and equipment reveals the development trend of marine water resources sampling technology, for example, the need for high temporal and spatial accuracy in sampling, etc. Finally, it explores the challenges facing deep-sea water sampling technology regarding future research, development and equipment industrialization. These reviews not only help researchers better understand the current development of marine water sampling technologies but also provide an important reference for the future development of marine water sampling technology, which provides guidance and support for in-depth marine scientific research and effective use of marine resources.

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Seasonal changes in metal and nutrient fluxes across the sediment-water interface in tropical mangrove creeks in the Amazon region

Cited by 14 publications

References 86 publications

Transformations of Ferrihydrite–Extracellular Polymeric Substance Coprecipitates Driven by Dissolved Sulfide: Interrelated Effects of Carbon and Sulfur Loadings

Transformations of Ferrihydrite–Extracellular Polymeric Substance Coprecipitates Driven by Dissolved Sulfide: Interrelated Effects of Carbon and Sulfur Loadings

Overlooked riverine contributions of dissolved neodymium and hafnium to the Amazon estuary and oceans

Advances and development in sampling techniques for marine water resources: a comprehensive review

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