Globally, the methane (CH4) efflux from ocean to atmosphere is small, despite high rates of CH4 production in continental shelf and slope environments. This low results biological removal through anaerobic oxidation with sulfate marine sediments. In some settings, however, pore water found throughout sulfate-bearing zone, indicating an apparently inefficient barrier for CH4. Here we demonstrate that rapid sediment accumulation can explain this limited capacity coastal a saline reservoir...

Methane (CH 4 ) is a key greenhouse gas. Coastal areas account for major proportion of marine CH emissions. Eutrophication and associated bottom water hypoxia enhance production in coastal sediments. Here, we assess the fate produced sediments at site seasonally anoxic eutrophic basin (Scharendijke, Lake Grevelingen, Netherlands) spring (March) late summer (September) 2020. Removal sediment through anaerobic oxidation with sulfate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Coastal zones account for 75% of marine methane emissions, despite covering only 15% the ocean surface area. In these ecosystems, tight balance between production and oxidation in sediments prevents most from escaping into seawater. However, anthropogenic activities could disrupt this balance, leading to an increased escape coastal sediments. To quantify unravel potential mechanisms underlying disruption, we used a suite biogeochemical microbiological analyses investigate impact...

Aeration followed by rapid sand filtration is a common method in drinking water treatment to remove iron (Fe) and manganese (Mn) from anoxic groundwater. To ensure the successful removal of Fe Mn within single filter, several factors such as raw characteristics, backwash procedures chemical microbial interactions with filter medium need be considered. Here, we assess characteristics highly efficient Mn. Using synchrotron X-ray spectroscopy, show that formation ferrihydrite-type oxides top...

Oxygen depletion in coastal waters may lead to release of toxic sulfide from sediments. Cable bacteria can limit by promoting iron oxide formation Currently, it is unknown how widespread this phenomenon is. Here, we assess the abundance, activity, and biogeochemical impact cable at 12 Baltic Sea sites. were mostly absent sediments overlain anoxic sulfidic bottom waters, emphasizing their dependence on oxygen or nitrate as electron acceptors. At sites that temporarily reoxygenated, bacterial...

Rapid sand filtration is a common method for removal of iron (Fe), manganese (Mn) and ammonium (NH4+) from anoxic groundwaters used drinking water production. In this study, we combine geochemical microbiological data to assess how filter age influences Fe, Mn NH4+ in dual media filters, consisting anthracite overlying quartz sand, that have been operation between ∼2 months ∼11 years. We show the depth where dissolved Fe occurs reflected medium coatings, with ferrihydrite forming top filters...

Abstract In coastal waters, methane-oxidizing bacteria (MOB) can form a methane biofilter and mitigate emissions. The metabolism of these MOBs is versatile, the resilience to changing oxygen concentrations potentially high. It still unclear how seasonal changes in availability water column chemistry affect functioning MOB community composition. Here, we determined depth profiles, methanotrophic structure, oxidation potential, water–air fluxes eutrophic marine basin during summer...

Coastal environments are a major source of marine methane in the atmosphere. Eutrophication and deoxygenation have potential to amplify coastal emissions. Here, we investigate dynamics eutrophic Stockholm Archipelago. We cover range sites with contrasting water column redox conditions rates organic matter degradation, latter reflected by depth sulfate-methane transition zone (SMTZ) sediment. find highest benthic release (2.2-8.6 mmol m

Abstract. Estuarine sediments are key sites for removal of phosphorus (P) from rivers and the open sea. Vivianite, an Fe(II)-P mineral, can act as a major sink P in Fe-rich coastal sediments. In this study, we investigate burial Öre Estuary northern Baltic Sea. We find much higher rates at our five study (up to ∼0.145 molm-2yr-1) when compared more southern areas Sea with similar sedimentation. Detailed sediment forms site highest rate sedimentation reveals role associated Fe presence...

Abstract. Coastal systems can act as filters for anthropogenic nutrient input into marine environments. Here, we assess the processes controlling removal of phosphorus (P) and nitrogen (N) four sites in eutrophic Stockholm archipelago. Bottom water concentrations oxygen (O2) P are inversely correlated. This is attributed to seasonal release from iron-oxide-bound (Fe-oxide-bound) surface sediments degrading organic matter. The abundant presence sulfide pore its high upward flux towards...

Abstract Continental shelves are a major source of iron (Fe) and manganese (Mn) to marine waters. Here, we investigate controls on benthic release Fe Mn the impact water column in Baltic Sea. We find high situ rates dissolved at seasonally hypoxic sites (bottom oxygen between 0–63 μ mol L −1 ) receiving inputs organic matter. that is sensitive bottom concentrations. Benthic likely additionally controlled by Fe–sulfur redox chemistry surface sediment. For Mn, correlates positively with oxide...

Abstract The Bothnian Sea is an oligotrophic brackish basin characterized by low salinity and high concentrations of reactive iron, methane, ammonium in its sediments, enabling the activity interactions many microbial guilds. Here, we studied network these sediments analyzing geochemical community depth profiles at one offshore two near coastal sites. Analysis 16S rRNA gene amplicons revealed a distinct stratification both archaeal bacterial taxa. communities sites were more similar to each...

Continental shelf sediments are a key source of trace metals to the ocean. In this study, we investigate impact sedimentary processes on water column concentrations iron (Fe), manganese (Mn), cobalt (Co), and nickel (Ni) at five stations Louisiana continental slope, Gulf Mexico. The highest metal were observed close seafloor most nearshore station (water depth 16 m), with present in particulate form. This enrichment bottom is likely combined effect input suspended matter from...

Enhanced recycling of phosphorus as ocean deoxygenation expanded under past greenhouse climates contributed to widespread organic carbon burial and drawdown atmospheric CO 2 . Redox-dependent was more efficient in such ancient anoxic marine environments, compared modern settings, for reasons that remain unclear. Here, we show low rates apatite authigenesis organic-rich sediments can explain the amplified settings reflected highly elevated ratios total phosphorus. We argue may be partly...

The potential and drivers of microbial methane removal in the water column seasonally stratified coastal ecosystems importance methanotrophic community composition for ecosystem functioning are not well explored. Here, we combined depth profiles oxygen with 16S rRNA gene amplicon sequencing, metagenomics oxidation rates at discrete depths a marine system (Lake Grevelingen, Netherlands). Three sequence variants (ASVs) belonging to different genera aerobic Methylomonadaceae corresponding three...

Coastal waters worldwide suffer from increased eutrophication and seasonal bottom water hypoxia. Here, we assess the dynamics of iron (Fe), manganese (Mn), phosphorus (P) in sediments eutrophic, brackish Gulf Finland populated by cable bacteria. At sites where are oxic spring, surface enrichments Fe Mn oxides high abundances bacteria were observed upon sampling early summer. one site, P enriched a thin layer (~ 3 mm) just below sediment-water interface. X-ray absorption near edge structure...

An existing sequential extraction scheme for particulate iron (Fe) is evaluated manganese (Mn) using a range of Mn standards. The consists 5 steps and quantifies operationally defined pools (1) poorly ordered oxides phosphates (ascorbic acid extractable); (2) carbonates sulfides (1 M HCl extractable), (3 4) crystalline (citrate buffered dithionite ammonium oxalate extractable, respectively) (5) associated with pyrite (concentrated HNO3 extractable). Application the to coastal sediments from...

Methane is a powerful greenhouse gas that produced in large quantities marine sediments. Microbially mediated oxidation of methane sediments, when balance with production, prevents the release to overlying water. Here, we present gene-based reactive transport model includes both microbial and geochemical dynamics use it investigate whether rate growth oxidizers sediments impacts efficiency filter. We focus on iron- methane-rich coastal and, model, show at our site, up 10% all removed...

The production of methane in coastal sediments and its release to the water column is intensified by anthropogenic eutrophication bottom hypoxia, it still uncertain whether emissions atmosphere will be enhanced. Here, we assess seasonal variations dynamics a eutrophic, seasonally euxinic basin (Scharendijke, Lake Grevelingen). In-situ benthic chamber incubations reveal high rates from sediment (74 – 163 mmol m−2 d−1) during monthly measurements between March October 2021. Comparison these...

Microbial methane oxidation is a major biofilter preventing larger emissions of this powerful greenhouse gas from marine coastal areas into the atmosphere. In these zones, various electron acceptors such as sulfate, metal oxides, nitrate, or oxygen can be used. However, key microbial players and mechanisms are poorly understood. study, we inoculated bioreactor with methane- iron-rich sediments Bothnian Sea to investigate iron cycling under low concentrations. Using metagenomics, investigated...

Sediments are a key sink for phosphorus (P) in coastal systems. This allows areas to act as filter P that is transported from land sea. Recent work suggests vivianite-type ferrous iron (Fe(II))-P minerals may be more important sediments than previously thought. Here, we investigate the occurrence of such three eutrophic sites with contrasting dynamics respect (Fe) and sulfur (S), covering salinity range 0 7. We only find authigenic at low intermediate sites, where Fe available excess over...