Marine Chemistry最新文献

{"title":"Spatiotemporal variability in benthic-pelagic coupling on the Oregon-Washington shelf","authors":"Anna Hughes ,&nbsp;Clare E. Reimers,&nbsp;Kristen E. Fogaren,&nbsp;Yvan Alleau","doi":"10.1016/j.marchem.2024.104473","DOIUrl":"10.1016/j.marchem.2024.104473","url":null,"abstract":"<div><div>Continental shelf sediments are sinks for dissolved oxygen (DO) and sources of many major and minor nutrients required for oceanic surface primary production resulting in a strong coupling between benthic and pelagic biogeochemical cycling. In this study, we present paired benthic flux and bottom water biogeochemical data collected from two Oregon shelf sites sampled approximately quarter-annually between 2017 and 2019, and from nine other shelf sites, located off central Oregon to southern Washington, and sampled in either July or September 2022. The benthic fluxes were determined using a novel set-up for <em>ex situ</em> core incubations. When fluxes were normalized to the respective measured sediment DO flux, ratios aligned well with ratios of past flux estimates from the region which were determined using <em>in situ</em> benthic chambers; however, the <em>ex situ</em> flux magnitudes are generally lower. Our findings demonstrate sediments acting as net sinks for DO and nitrate, and sources for phosphate, silicate, and ammonium. Shelf-wide estimates of the relative contribution of sediment-remineralized phosphate and silicate to surface waters on the Oregon shelf, indicate that shelf sediments supplied at least 5 ± 7 % and 37 ± 7 % of the available phosphate and silicate during recent summer upwelling seasons, with similar, respective estimates of 2 ± 9 % and 35 ± 11 % during the spring. Remineralization ratios of C:N:P:O₂ corroborate increased denitrification during the summer and weak denitrification during the winter due to a more oxygenated water column in support of previous studies. A multi-tracer water mass analysis also exhibited an increased water-column nitrate deficit during the summer and fall. Benthic denitrification rates, estimated from benthic fluxes, were between 0.2 and 1.8 mmol N m^-2 day^-1 and in the range of past assessments during the upwelling season. A simple model, applied to further constrain the contributions to bottom water fixed nitrogen (N) loss under assumptions of benthic boundary layer height and residence time, showed that although sediment denitrification could readily account for total bottom water N losses during the summer, additional water-column denitrification is indicated by the strength of early fall deficits at some stations. Constraining water-column and benthic contributions to fixed N deficits is important for understanding how N-limited primary productivity in this region will respond to projected ocean deoxygenation under anticipated global warming. These results demonstrate the interplay of sediment and water-column remineralization processes across the OR-WA shelf. As in most shallow marine systems, the two are integral to the ecosystem dynamics and responses to environmental change.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"268 ","pages":"Article 104473"},"PeriodicalIF":3.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrous oxide variability along an estuary influenced by agricultural land use (Guadalquivir estuary, SW Spain)","authors":"J. Sánchez-Rodríguez ,&nbsp;A. Sierra ,&nbsp;S. Moreno ,&nbsp;J. Forja ,&nbsp;T. Ortega","doi":"10.1016/j.marchem.2024.104467","DOIUrl":"10.1016/j.marchem.2024.104467","url":null,"abstract":"<div><div>The Guadalquivir Estuary is the largest estuary in the southwest basin of the Iberian Peninsula, which is subject to strong anthropogenic influence such as the damming or the multitude of crop fields on its margins. Nitrous Oxide (N₂O) variability is analysed considering the influence of temperature, salinity, water-atmosphere fluxes, benthic fluxes, reactivity and lateral inputs. N₂O increases along the salinity gradient, with values ranging from 5.9 to 103.3 nmol L⁻¹. Thus, values of N₂O concentration are very close to equilibrium with the atmosphere at the mouth, while in the inner zone the fluxes to the atmosphere are higher, showing the greatest variability of N₂O in the estuary (74.26 ± 7.41 μmol m⁻² d⁻¹). Sediments act as a source of N₂O to the water column, with benthic fluxes presenting a wide range from 2 to 20 μmol m⁻² d⁻¹. Denitrification processes in the sediments may be important in the inner part of the estuary, where negative benthic fluxes of nitrate have been observed. Production rates of N₂O in the water column are estimated from incubation experiments, resulting in higher production with temperature, and lower with salinity. Lateral inputs are calculated by balance of the different processes characterized and seems to be an important factor influencing N₂O variability in the inner zone of the estuary.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104467"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sea-air CO2 exchanges, pCO2 drivers and phytoplankton communities in the southwestern South Atlantic Ocean during spring","authors":"Rodrigo Kerr ,&nbsp;Thiago Monteiro ,&nbsp;Iole Beatriz M. Orselli ,&nbsp;Virginia Maria Tavano ,&nbsp;Carlos Rafael B. Mendes","doi":"10.1016/j.marchem.2024.104472","DOIUrl":"10.1016/j.marchem.2024.104472","url":null,"abstract":"<div><div>Hydrographic properties and carbon dioxide partial pressure (<em>p</em>CO₂) were measured through underway survey of surface waters during spring 2014, mainly along the Surface Haline Front in the continental shelf-break domain in the southwestern South Atlantic Ocean margin. Additionally, discrete seawater surface samples were collected along the ship track to identify the phytoplankton community and measure seawater chemical properties. This study aims to identify the drivers of the marine CO₂‑carbonate chemistry and the role played by the phytoplankton composition on changes in the surface marine carbonate properties and the sea-air CO₂ exchanges in two biogeochemical provinces (i.e., South Brazil Bight – SBB, and Southern Brazilian Shelf – SBS) governed by the dynamics of the Brazil Current system in the South Atlantic Ocean. The water masses identified on the surface of the region were Tropical Water (mostly present at offshore regions), Subtropical Shelf Water (mostly present over the continental shelf and slope), and Plata Plume Water (present in the south coastal domain of the SBS). On average, the study area behaved as a weak net CO₂ outgassing zone of 1.2 ± 2.3 mmol m⁻² d⁻¹ during the spring, despite some subregions behaving as CO₂ ingassing zones. The CO₂ uptake verified in the SBB was related with mesoscale activity bringing cold waters in the region while CO₂ uptake in the continental shelf domain of SBS was associated with the presence of cooler and fresher Plata Plume Water. Changes in total alkalinity and dissolved inorganic carbon at surface were mainly governed by CaCO₃ production in SBB and seawater dilution in SBS, although other processes may also have influenced on their spatial variability. The dominant phytoplankton groups were haptophytes (31 %), <em>Trichodesmium</em> (21 %), and picocyanobateria (28 %), corresponding to <em>Synechococcus</em> (17 %) and <em>Prochlorococcus</em> (11 %). The dominance of the diatom group was associated with a decrease in sea surface <em>p</em>CO₂ (mainly at coastal zones at southern areas), although the sea-air CO₂ exchanges were regulated by cooling process due the presence of Plata Plume Water in that region. Changes in surface pH were related to high concentration of <em>Trichodesmium</em> slicks at offshore zones with the highest microalgae concentration, leading to pH drops of up to 0.4. <em>Trichodesmium</em> slicks likely allowed the development of haptophytes in offshore oligotrophic waters due to its role on N₂ fixation. An increase of ∼20 % in the dominance of haptophytes contribution was verified in that situation, which was likely in a post-bloom development stage, since an increased dissolved inorganic carbon content was observed, associated with a prevalence of net respiration processes.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104472"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal variation of CO2 air-sea flux and effects of warming in the Kuroshio Current of the East China Sea","authors":"Shou-En Tsao ,&nbsp;Po-Yen Shen ,&nbsp;Chun-Mao Tseng","doi":"10.1016/j.marchem.2024.104469","DOIUrl":"10.1016/j.marchem.2024.104469","url":null,"abstract":"<div><div>The partial pressure of CO₂ (<em>p</em>CO₂) and associated CO₂ air-sea flux exhibit highly heterogeneous temporal and spatial patterns in ocean margins. In this study, we analyzed a three-year time-series of data sampled during 2011–2014 along the Kuroshio Current within the East China Sea (ECS) to investigate the seasonal pattern of carbonate chemistry and CO₂ air-sea fluxes. Annually, the Kuroshio within the ECS operates as a net CO₂ sink at approximately 1.3 mol C m⁻² yr⁻¹, less than estimates over the ECS shelf (∼1.8 mol C m⁻² yr⁻¹). The thermal control of <em>p</em>CO₂ makes the Kuroshio a strong CO₂ sink in winter, with a transition to net-neutral, or a weak CO₂ source in summer. On an interannual basis, however, the seasonal CO₂ air-sea fluxes in the Kuroshio may undergo shifts if warming conditions continue.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104469"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reactivity and fluxes of antimony in a macrotidal estuarine salinity gradient: Insights from single and triple quadrupole ICP-MS performances","authors":"Teba Gil-Díaz ,&nbsp;Frédérique Pougnet ,&nbsp;Lionel Dutruch ,&nbsp;Jörg Schäfer ,&nbsp;Alexandra Coynel","doi":"10.1016/j.marchem.2024.104465","DOIUrl":"10.1016/j.marchem.2024.104465","url":null,"abstract":"<div><div>Trace element analyses in brackish waters are challenging for many elements at ppb/ppt levels and analytical methods. In this work, we compare two methods using inductively coupled plasma mass spectrometry (ICP-MS) for quantifying antimony (Sb). Results of a previous study along the salinity gradient in a macrotidal estuary (i.e., the Gironde Estuary, France) using isotopic dilution via single quadrupole ICP-MS are compared to reanalyzed aliquots of the same samples. Direct analyses of estuarine water samples via standard additions (<em>N</em> = 52) were performed with a QQQ-ICP-MS (new generation, iCAP TQ Thermo®) to determine dissolved (&lt; 0.2 μm filtered and UV-irradiated replicates) Sb concentrations during two contrasting hydrological conditions (low vs high freshwater discharges). Despite following good analytical practices on both studies, the use of the new analytical device provides more robust results and highlighted a characteristic ¹²¹Sb isotopic interference in estuarine samples at S &gt; 20, efficiently eliminated by the QQQ-ICP-MS performance. This means that Sb reactivity shows an additive, non-conservative behavior in the Gironde Estuary, with a more defined bell-shaped profile in low discharge compared to high discharge conditions. This approach allows to quantify for the first time in the literature Sb dissolved net fluxes from the Gironde Estuary to the Atlantic coast and provides an updated value for the seawater endmember. This study opens future applications of QQQ-ICP-MS for quantifying on a more routine basis dissolved trace elements in brackish waters, providing guidelines and good practices for field studies regarding Sb determination in estuarine systems.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104465"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracing marine and terrestrial biochemical signatures of particulate organic matter in an Arctic fjord (Kongsfjorden)","authors":"Archana Singh ,&nbsp;Anand Jain ,&nbsp;Richa Singh ,&nbsp;Keisham S. Singh ,&nbsp;Biswajit Roy ,&nbsp;Manish Tiwari ,&nbsp;Divya David T. ,&nbsp;Ashok Jagtap","doi":"10.1016/j.marchem.2024.104468","DOIUrl":"10.1016/j.marchem.2024.104468","url":null,"abstract":"<div><div>Arctic fjords are hotspot for organic matter (OM) transformation and storage, however, the composition and sources of the particulate organic matter (POM) are still not completely understood. Further, due to the ongoing enhancement in the glacier melting, runoff, and precipitation, the coastal Arctic is expecting considerable increase in POM inputs. Therefore, we investigated the biochemical composition of the POM through the application of stable isotopes, C:N ratio, and biomolecules, across different regions and depths in Kongsfjorden (Svalbard) during the late-summer. We observed that Kongsfjorden-POM was characterized by low δ¹³C (−29.0 to −26.7 ‰) with similar values at different locations (inner to outer) of the fjord at each depth. However, C:N ratio showed increasing trend (5.7 to 10.9) from outer to inner fjord indicating marine to terrestrial transition. Monosaccharide distribution (such as fucose, galactose, arabinose, xylose, ribose, and rhamnose) and their diagnostic ratios supported the marine versus terrestrial gradient in the POM characteristics in the surface water across the fjord. Only the outermost station showed consistent biochemical distribution indicative of phytoplanktonic sources in the POM, while the rest of the fjord showed mixed signatures of marine and terrestrial sources. Higher abundance of mannuronic acid (26.6–50.8 mol%) at the middle and bottom depths highlighted possible macroalgal contribution to the POM. The stratified surface water had a relatively higher (0.5–2 ‰) δ¹³C and carbohydrates (40–65 μg/L) than the middle and bottom depths, with a strong positive correlation between δ¹³C and particulate carbohydrates, indicating a stratification-induced distribution of POM. The study showed the importance of non-phytoplanktonic OM sources, such as terrestrial, freshwater and macroalgae POM in the fjord water column, and the fate of labile (carbohydrates) fraction that predominates in stratified surface waters. Therefore, the future warm and wet Arctic will most likely lead to changes in the fate of the organic matter in the fjord water.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104468"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic manganese cycling in the northern Gulf of Mexico","authors":"Jessalyn E. Davis ,&nbsp;Rebecca S. Robinson ,&nbsp;Emily R. Estes ,&nbsp;Veronique E. Oldham ,&nbsp;Evan A. Solomon ,&nbsp;Roger P. Kelly ,&nbsp;Katherine E. Bell ,&nbsp;Joseph A. Resing ,&nbsp;Randelle M. Bundy","doi":"10.1016/j.marchem.2024.104466","DOIUrl":"10.1016/j.marchem.2024.104466","url":null,"abstract":"<div><div>Transport processes along the river-ocean continuum influence delivery of nutrients, carbon and trace metals from terrestrial systems to the marine environment, impacting coastal primary productivity and water quality. Although trace metal transformations have been studied extensively in the Mississippi River Delta region of the Northern Gulf of Mexico, investigations of manganese (Mn) and the presence of ligand-stabilized, dissolved manganese (Mn(III)-L) and its role in the transformation of trace elements and organic matter during riverine transport and estuarine mixing have not been considered. This study examined the chemical speciation of dissolved and particulate Mn in the water column and sediment porewaters in the Mississippi River and Northern Gulf of Mexico in March of 2021 to explore transformations in Mn speciation along the river-ocean continuum and the impact of different processes on the distribution of Mn. Total dissolved Mn concentrations were highest in the Mississippi River and decreased offshore, while Mn(III)-L contributed most to the dissolved Mn pool in near-shore waters. Porewater profiles indicated that ligand stabilization prevented dissolved Mn(III) reduction below the depth of oxygen penetration and in the presence of equimolar dissolved iron(II). Dissolved Mn(III)-L was enriched in bottom waters at all Northern Gulf of Mexico stations, and diffusive flux modelling of porewater dissolved Mn suggested that reducing sediments were a source of dissolved Mn to the overlying water column in the form of both reduced Mn(II) and Mn(III)-L. A simple box model of the Mn cycle in the Northern Gulf of Mexico indicates that Mn(III)-L is required to balance the Mn budget in this region and is an integral, and previously unconsidered, piece of the Mn cycle in the Northern Gulf of Mexico. The presence of Mn(III)-L in this system likely has an outsized impact on trace element scavenging rates, oxidative capacity, and the carbon cycle that have not been previously appreciated.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104466"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boron to salinity ratios in the Fram Strait entering the Central Arctic: The role of sea ice formation and future predictions","authors":"Samantha Rush ,&nbsp;Penny Vlahos ,&nbsp;Chang-Ho Lee ,&nbsp;Kitack Lee ,&nbsp;Lauren J. Barrett","doi":"10.1016/j.marchem.2024.104463","DOIUrl":"10.1016/j.marchem.2024.104463","url":null,"abstract":"<div><div>The Arctic Ocean's sea ice loss dynamically impacts carbon uptake potential, as assessed through measured carbonate parameters, such as total alkalinity. In the open ocean, boron (B) is the third largest contributor to alkalinity via borate and is usually accounted for through the conservative boron to salinity ratio (B/S), and not directly measured. Here, we present findings on non-conservative boron dynamics, that results in significant B/S deviations, observed in ice melt zone waters, snow, slush, brine, and annual sea ice (<em>n</em> = 169) in the Fram Strait entering the Central Arctic. These samples were collected during the onset of the melt season on the 2023 ARTofMELT expedition, covering a wide practical salinity range (2–59). Barring snow, the average B/S ratio across the study was 0.1321 ± 0.0032 mg kg⁻¹ ‰⁻¹, similar to the mean B/S ratio measured amongst several polar water masses near Iceland, as well as the accepted B/S for other ocean regions. Results indicate minor deviations from accepted B/S ratios (indicating conservative behavior) across the sample practical salinity range and reflect an uncertainty in the borate contribution to total alkalinity of less than 2.9 μmol kg⁻¹ at in-situ temperatures. B fractionation appears to occur during sea ice formation, causing greater B in the sea ice reservoir whereas brine, slush, lead, and under-ice water reservoirs are depleted in B. As such, under-ice and lead, brine, and slush samples all had measured B/S ratios (0.1305 ± 0.0011, 0.1305 ± 0.0018, and 0.1304 ± 0.0017 mg kg⁻¹ ‰⁻¹, respectively) lower than the established ratio whereas the average sea ice B/S ratio (0.1331 ± 0.0035 mg kg⁻¹ ‰⁻¹) was closest to accepted values (0.1336 ± 0.0005 mg kg⁻¹ ‰⁻¹). Arctic open ocean samples also had a lower B/S ratio (0.1304 ± 0.0014 mg kg⁻¹ ‰⁻¹). Our findings, together with a previous Arctic B ice study, suggest that B (probably in the form of B(OH)₄⁻) is incorporated into authigenic CaCO₃ minerals, replacing CO₃²⁻ within the mineral lattice during sea ice formation. This process consequentially lowers the B/S ratio in the open Arctic Ocean, compared to the established global ocean ratio. Nevertheless, the incorporation of B into the sea ice reservoir does not fully account for the deficit of B in the Arctic Ocean samples, suggesting further accounting of B Arctic pathways is necessary. In future climate scenarios involving increased sea ice melt, the transition from multiyear to annual sea ice, permafrost thaw, and increased riverine discharge, the behavior of B in the Arctic Ocean is expected to become more dynamic.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104463"},"PeriodicalIF":3.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biogeochemical sulfur transformations in the cohesive and permeable tidal flat sediments of Jade Bay (North Sea)","authors":"Alexey Kamyshny Jr ,&nbsp;Debora Sela ,&nbsp;Rotem Klein ,&nbsp;Alexandra V. Turchyn ,&nbsp;Gilad Antler ,&nbsp;Holger Freund","doi":"10.1016/j.marchem.2024.104464","DOIUrl":"10.1016/j.marchem.2024.104464","url":null,"abstract":"<div><div>Intertidal flats are highly productive coastal marine ecosystems which are affected by fast changes in environmental conditions and host dynamic biogeochemical cycles in their sediments. Bioturbation by burrowing organisms and roots of plants strongly affects speciation and cycling of redox-sensitive elements in intertidal sediments. In this work, we have studied the impact of sediment type and vegetation on the cycling of redox-sensitive elements including sulfur, iron, and manganese in sandy and muddy tidal flats sediments in the Jade Bay (North Sea) and adjacent area. The redox speciation of these elements was analyzed in the pore-waters and the total sediment. The isotopic compositions of sulfur species were measured in non-vegetated sediments and in sediments which are inhabited by various plants. In the cohesive sediments, which are not affected by vegetation, a decrease in sulfate concentration, coupled with the presence of relatively high concentrations of hydrogen sulfide in the pore-waters and the presence of sulfide minerals as well the isotopic compositions of sulfur species are consistent with fast rates of sulfate reduction in the sediments. In the cohesive sediments affected by roots of <em>Salicornia stricta</em> and sediments desiccation, a cryptic sulfur cycle, which is characterized by microbial sulfate reduction coupled to fast reoxidation of hydrogen sulfide by Fe(III) (hydr)oxides and, possibly, by oxygen is present. Below the roots penetration depth, speciation of redox-sensitive elements is similar to those in the baren sediments. In the cohesive sediments affected by the roots of <em>Spartina anglica</em> and <em>Triglochin maritima</em>, which have longer roots, a cryptic sulfur cycle was detected in the upper 30 cm of sediments. At the sites that are characterized by permeable surface sediments and alternating permeable and cohesive layers in the deeper sediments, the composition of the sediment has a similar or even more significant impact on the speciation of the redox-sensitive elements than penetration of relatively weak roots of <em>Spartina anglica</em>. These sediments are characterized by the formation of hydrogen sulfide and sulfide oxidation intermediates in the cohesive layers and their diffusion to (and oxidation at) the boundaries between cohesive and permeable sediments. We conclude that in the cohesive sediments, the penetration of roots and desiccation leads to the formation of overall oxidized conditions, while in the sediments with alternating layers, permeability may provide a more significant control for speciation of redox-sensitive elements.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104464"},"PeriodicalIF":3.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Characterizing the stable oxygen isotopic composition of the Southeast Indian Ocean” [Marine Chemistry 262 (2024) 104397]","authors":"Ryan H. Glaubke ,&nbsp;Amy J. Wagner ,&nbsp;Elisabeth L. Sikes","doi":"10.1016/j.marchem.2024.104460","DOIUrl":"10.1016/j.marchem.2024.104460","url":null,"abstract":"","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"267 ","pages":"Article 104460"},"PeriodicalIF":3.0,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}