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Abundance and Diversity of Denitrifying and Anammox Bacteria in Seasonally Hypoxic and Sulfidic Sediments of the Saline Lake Grevelingen Open
Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, d…
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Methane oxidation coupled to oxygenic photosynthesis in anoxic waters Open
Freshwater lakes represent large methane sources that, in contrast to the Ocean, significantly contribute to non-anthropogenic methane emissions to the atmosphere. Particularly mixed lakes are major methane emitters, while permanently and …
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Aerobic and anaerobic nitrogen transformation processes in N2-fixing cyanobacterial aggregates Open
Colonies of N2-fixing cyanobacteria are key players in supplying new nitrogen to the ocean, but the biological fate of this fixed nitrogen remains poorly constrained. Here, we report on aerobic and anaerobic microbial nitrogen transformati…
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Novel taxa of Acidobacteriota implicated in seafloor sulfur cycling Open
Acidobacteriota are widespread and often abundant in marine sediments, yet their metabolic and ecological properties are poorly understood. Here, we examined metabolisms and distributions of Acidobacteriota in marine sediments of Svalbard …
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Controls on the evolution of Ediacaran metazoan ecosystems: A redox perspective Open
A growing number of detailed geochemical studies of Ediacaran (635–541 Ma) marine successions have provided snapshots into the redox environments that played host to the earliest known metazoans. Whilst previous compilations have focused o…
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Metagenomics Reveals Microbial Diversity and Metabolic Potentials of Seawater and Surface Sediment From a Hadal Biosphere at the Yap Trench Open
Hadal biosphere represents the deepest part of the ocean with water depth >6,000 m. Accumulating evidence suggests the existence of unique microbial communities dominated by heterotrophic processes in this environment. However, investigati…
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Metagenomic analysis of nitrogen and methane cycling in the Arabian Sea oxygen minimum zone Open
Oxygen minimum zones (OMZ) are areas in the global ocean where oxygen concentrations drop to below one percent. Low oxygen concentrations allow alternative respiration with nitrate and nitrite as electron acceptor to become prevalent in th…
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Bacterial community structure across environmental gradients in permafrost thaw ponds: methanotroph-rich ecosystems Open
Permafrost thawing leads to the formation of thermokarst ponds that potentially emit CO2 and CH4 to the atmosphere. In the Nunavik subarctic region (northern Québec, Canada), these numerous, shallow ponds become well-stratified during summ…
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Photoferrotrophy: Remains of an Ancient Photosynthesis in Modern Environments Open
Photoferrotrophy, the process by which inorganic carbon is fixed into organic matter using light as an energy source and reduced iron [Fe(II)] as an electron donor, has been proposed as one of the oldest photoautotrophic metabolisms on Ear…
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Basin-scale controls on the molybdenum-isotope composition of seawater during Oceanic Anoxic Event 2 (Late Cretaceous) Open
It is well established that the burial of organic carbon in marine sediments increased dramatically at a global scale at the Cenomanian–Turonian boundary (Oceanic Anoxic Event 2: OAE-2, ∼94 Myr ago, Late Cretaceous). Many localities contai…
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A continental-weathering control on orbitally driven redox-nutrient cycling during Cretaceous Oceanic Anoxic Event 2 Open
The Cretaceous period (~145–65 m.y. ago) was characterized by intervals of enhanced organic carbon burial associated with increased primary production under greenhouse conditions. The global consequences of these perturbations, oceanic ano…
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Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes Open
The early Cambrian is a crucial interval, during which the marine environment encountered significant perturbations alongside key biological innovations. The nitrogen isotopic composition of ancient sediments has the potential to record co…
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Contrasting taxonomic stratification of microbial communities in two hypersaline meromictic lakes Open
Hypersaline meromictic lakes are extreme environments in which water stratification is associated with powerful physicochemical gradients and high salt concentrations. Furthermore, their physical stability coupled with vertical water colum…
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Decline of the Black Sea oxygen inventory Open
We show that from 1955 to 2015, the inventory of oxygen in the Black Sea has decreased by 44 % and the basin-averaged oxygen penetration depth has decreased from 140 m in 1955 to 90 m in 2015, which is the shallowest annual value recorded …
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Winter Limnology as a New Frontier Open
No one seeks the most improved award. But if Limnology were to recognize a most improved topic, our vote in 2016 would go to winter limnology. While much work still remains, we are cautiously optimistic about recent progress in winter limn…
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Microbial ecology of deep-sea hypersaline anoxic basins Open
Deep hypersaline anoxic basins (DHABs) are unique water bodies occurring within fractures at the bottom of the sea, where the dissolution of anciently buried evaporites created dense anoxic brines that are separated by a chemocline/pycnocl…
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The microbiome of the Black Sea water column analyzed by shotgun and genome centric metagenomics Open
Background The Black Sea is the largest brackish water body in the world, although it is connected to the Mediterranean Sea and presents an upper water layer similar to some regions of the former, albeit with lower salinity and temperature…
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Metatranscriptomic analysis of prokaryotic communities active in sulfur and arsenic cycling in Mono Lake, California, USA Open
This study evaluates the transcriptionally active, dissimilatory sulfur- and arsenic-cycling components of the microbial community in alkaline, hypersaline Mono Lake, CA, USA. We sampled five depths spanning the redox gradient (10, 15, 18,…
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Succession of Bacterial Communities in a Seasonally Stratified Lake with an Anoxic and Sulfidic Hypolimnion Open
Although bacteria play key roles in aquatic food webs and biogeochemical cycles, information on the seasonal succession of bacterial communities in lakes is still far from complete. Here, we report results of an integrative study on the su…
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Impact of Seasonal Hypoxia on Activity and Community Structure of Chemolithoautotrophic Bacteria in a Coastal Sediment Open
Seasonal hypoxia in coastal systems drastically changes the availability of electron acceptors in bottom water, which alters the sedimentary reoxidation of reduced compounds. However, the effect of seasonal hypoxia on the chemolithoautotro…
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<i>Arcobacter peruensis</i> sp. nov., a Chemolithoheterotroph Isolated from Sulfide- and Organic-Rich Coastal Waters off Peru Open
Our multidisciplinary approach provides new insights into the ecophysiology of a newly isolated environmental Arcobacter species, as well as the physiological flexibility within the Arcobacter genus and sulfide-oxidizing, denitrifying micr…
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Carbon and Sulfur Cycling below the Chemocline in a Meromictic Lake and the Identification of a Novel Taxonomic Lineage in the FCB Superphylum, Candidatus Aegiribacteria Open
Mahoney Lake in British Columbia is an extreme meromictic system with unusually high levels of sulfate and sulfide present in the water column. As is common in strongly stratified lakes, Mahoney Lake hosts a dense, sulfide-oxidizing photot…
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Life on the edge: active microbial communities in the Kryos MgCl2-brine basin at very low water activity Open
The Kryos Basin is a deep-sea hypersaline anoxic basin (DHAB) located in the Eastern Mediterranean Sea (34.98°N 22.04°E). It is filled with brine of re-dissolved Messinian evaporites and is nearly saturated with MgCl2-equivalents, which ma…
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Water column and sediment stable carbon isotope biogeochemistry of permanently redox‐stratified Fayetteville Green Lake, New York, U.S.A. Open
Carbon cycling in natural ecosystems is a biologically mediated process with global consequences. Recent work has revealed the important role that lakes play in the global carbon cycle, suggesting organic carbon burial in small lakes and r…
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Microbial carbon, sulfur, iron, and nitrogen cycling linked to the potential remediation of a meromictic acidic pit lake Open
Cueva de la Mora is a permanently stratified acidic pit lake and a model system for extreme acid mine drainage (AMD) studies. Using a combination of amplicon sequencing, metagenomics and metatranscriptomics we performed a taxonomically res…
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Biogeochemical and 16S rRNA gene sequence evidence supports a novel mode of anaerobic methanotrophy in permanently ice‐covered Lake Fryxell, Antarctica Open
Lake Fryxell, McMurdo Dry Valleys, Antarctica contains a constantly cold water column and perennial ice‐cover. Although carbon and sulfur cycling in this amictic lake have been studied previously, a paired investigation of 16S rRNA gene ba…
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Oxygenation of Hypoxic Coastal Baltic Sea Sediments Impacts on Chemistry, Microbial Community Composition, and Metabolism Open
The Baltic Sea has undergone severe eutrophication during the last century, resulting in increased algal blooms and the development of hypoxic bottom waters. In this study, we sampled oxygen deficient sediment cores from a Baltic Sea coast…
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Lower Wenlock black shales in the northern Holy Cross Mountains, Poland: sedimentary and geochemical controls on the Ireviken Event in a deep marine setting Open
The stratigraphic variability and geochemistry of Llandovery/Wenlock (L/W) Series boundary sediments in Poland reveals that hemipelagic sedimentation under an anoxic/euxinic water column was interrupted by low-density bottom currents or de…
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Spatio-temporal dynamics of sulfur bacteria during oxic--anoxic regime shifts in a seasonally stratified lake Open
Sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria drive major transformations in the sulfur cycle, and play vital roles in oxic--anoxic transitions in lakes and coastal waters. However, information on the succession of these su…
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Geochemical Characterization of Two Ferruginous Meromictic Lakes in the Upper Midwest, USA Open
To elucidate the role of (bio)geochemical processes that fueled iron and carbon cycling in early Earth oceans, modern environments with similar geochemical conditions are needed. As the range of chemical, physical, and biological attribute…