Pacmanvirus isolated from the Lost City hydrothermal field extends the concept of transpoviron beyond the family Mimiviridae.

The microbial sampling of submarine hydrothermal vents remains challenging, with even fewer studies focused on viruses. Here we report what is to our knowledge the first isolation of a eukaryotic virus from the Lost City hydrothermal field, by co-culture with the laboratory host Acanthamoeba castellanii. This virus, named pacmanvirus lostcity, is closely related to previously isolated pacmanviruses (strains A23 and S19), clustering in a divergent clade within the long-established family Asfarviridae.

A long section of serpentinized depleted mantle peridotite.

The upper mantle is critical for our understanding of terrestrial magmatism, crust formation, and element cycling between Earth's solid interior, hydrosphere, atmosphere, and biosphere. Mantle composition and evolution have been primarily inferred by surface sampling and indirect methods. We recovered a long (1268-meter) section of serpentinized abyssal mantle peridotite interleaved with thin gabbroic intrusions.

Globally-distributed microbial eukaryotes exhibit endemism at deep-sea hydrothermal vents.

Single-celled microbial eukaryotes inhabit deep-sea hydrothermal vent environments and play critical ecological roles in the vent-associated microbial food web. 18S rRNA amplicon sequencing of diffuse venting fluids from four geographically- and geochemically-distinct hydrothermal vent fields was applied to investigate community diversity patterns among protistan assemblages. The four vent fields include Axial Seamount at the Juan de Fuca Ridge, Sea Cliff and Apollo at the Gorda Ridge, all in the NE Pacific Ocean, and Piccard and Von Damm at the Mid-Cayman Rise in the Caribbean Sea.

Metabolic Strategies Shared by Basement Residents of the Lost City Hydrothermal Field.

Alkaline fluids venting from chimneys of the Lost City hydrothermal field flow from a potentially vast microbial habitat within the seafloor where energy and organic molecules are released by chemical reactions within rocks uplifted from Earth's mantle. In this study, we investigated hydrothermal fluids venting from Lost City chimneys as windows into subseafloor environments where the products of geochemical reactions, such as molecular hydrogen (H), formate, and methane, may be the only available sources of energy for biological activity. Our deep sequencing of metagenomes and metatranscriptomes from these hydrothermal fluids revealed a few key species of archaea and bacteria that are likely to play critical roles in the subseafloor microbial ecosystem.

Particulate and Dissolved Organic Matter in Stormwater Runoff Influences Oxygen Demand in Urbanized Headwater Catchments.

Increasing inputs of organic matter (OM) are driving declining dissolved oxygen (DO) concentrations in coastal ecosystems worldwide. The quantity, source, and composition of OM transported to coastal ecosystems via stormwater runoff have been altered by land use changes associated with urbanization and subsequent hydrologic flows that accompany urban stormwater management. To elucidate the role of stormwater in the decline of coastal DO, rain event sampling of biochemical oxygen demand (BOD) in samples collected from the outfall of stormwater ponds and wetlands, as well as samples of largely untreated runoff carried by stormwater ditches, was conducted across a range of urban and suburban development densities.

Enzyme-free synthesis of natural phospholipids in water.

All living organisms synthesize phospholipids as the primary constituent of their cell membranes. Enzymatic synthesis of diacylphospholipids requires preexisting membrane-embedded enzymes. This limitation has led to models of early life in which the first cells used simpler types of membrane building blocks and has hampered integration of phospholipid synthesis into artificial cells.

Genomic Evidence for Formate Metabolism by as the Key to Unlocking Deep Carbon in Lost City Microbial Ecosystems.

The Lost City hydrothermal field on the Mid-Atlantic Ridge supports dense microbial life on the lofty calcium carbonate chimney structures. The vent field is fueled by chemical reactions between the ultramafic rock under the chimneys and ambient seawater. These serpentinization reactions provide reducing power (as hydrogen gas) and organic compounds that can serve as microbial food; the most abundant of these are methane and formate.

An artificial habitat increases the reproductive fitness of a range-shifting species within a newly colonized ecosystem.

When a range-shifting species colonizes an ecosystem it has not previously inhabited, it may experience suboptimal conditions that challenge its continued persistence and expansion. Some impacts may be partially mitigated by artificial habitat analogues: artificial habitats that more closely resemble a species' historic ecosystem than the surrounding habitat. If conditions provided by such habitats increase reproductive success, they could be vital to the expansion and persistence of range-shifting species.

Habitability of the marine serpentinite subsurface: a case study of the Lost City hydrothermal field.

The Lost City hydrothermal field is a dramatic example of the biological potential of serpentinization. Microbial life is prevalent throughout the Lost City chimneys, powered by the hydrogen gas and organic molecules produced by serpentinization and its associated geochemical reactions. Microbial life in the serpentinite subsurface below the Lost City chimneys, however, is unlikely to be as dense or active.

Growth Kinetics, Carbon Isotope Fractionation, and Gene Expression in the Hyperthermophile during Hydrogen-Limited Growth and Interspecies Hydrogen Transfer.

Hyperthermophilic methanogens are often H limited in hot subseafloor environments, and their survival may be due in part to physiological adaptations to low H conditions and interspecies H transfer. The hyperthermophilic methanogen was grown in monoculture at high (80 to 83 μM) and low (15 to 27 μM) aqueous H concentrations and in coculture with the hyperthermophilic H producer The purpose was to measure changes in growth and CH production kinetics, CH fractionation, and gene expression in with changes in H flux. Growth and cell-specific CH production rates of decreased with decreasing H availability and decreased further in coculture.

Enrichments of Metals, Including Methylmercury, in Sewage Spills in South Carolina, USA.

Exposure to microbial pathogens is the primary concern of sanitary sewer overflows; however, sewage spills may also be a significant source of toxic metals, including methylmercury (MeHg). Between November 2015 and January 2017, after Hurricane Joaquin, surface water samples were collected routinely from three creeks in Columbia, SC. Routine sampling coincided with six sewage spills.

Serpentinization: Connecting Geochemistry, Ancient Metabolism and Industrial Hydrogenation.

Rock⁻water⁻carbon interactions germane to serpentinization in hydrothermal vents have occurred for over 4 billion years, ever since there was liquid water on Earth. Serpentinization converts iron(II) containing minerals and water to magnetite (Fe₃O₄) plus H₂. The hydrogen can generate native metals such as awaruite (Ni₃Fe), a common serpentinization product.

Deeply-sourced formate fuels sulfate reducers but not methanogens at Lost City hydrothermal field.

Hydrogen produced during water-rock serpentinization reactions can drive the synthesis of organic compounds both biotically and abiotically. We investigated abiotic carbon production and microbial metabolic pathways at the high energy but low diversity serpentinite-hosted Lost City hydrothermal field. Compound-specific C data demonstrates that formate is mantle-derived and abiotic in some locations and has an additional, seawater-derived component in others.

Mineralizing Filamentous Bacteria from the Prony Bay Hydrothermal Field Give New Insights into the Functioning of Serpentinization-Based Subseafloor Ecosystems.

Despite their potential importance as analogs of primitive microbial metabolisms, the knowledge of the structure and functioning of the deep ecosystems associated with serpentinizing environments is hampered by the lack of accessibility to relevant systems. These hyperalkaline environments are depleted in dissolved inorganic carbon (DIC), making the carbon sources and assimilation pathways in the associated ecosystems highly enigmatic. The Prony Bay Hydrothermal Field (PHF) is an active serpentinization site where, similar to Lost City (Mid-Atlantic Ridge), high-pH fluids rich in H and CH are discharged from carbonate chimneys at the seafloor, but in a shallower lagoonal environment.

Metagenomic identification of active methanogens and methanotrophs in serpentinite springs of the Voltri Massif, Italy.

The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy.

Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA).

Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as char and soot. PyC is ubiquitous in the environment due to its long persistence, and its abundance might even increase with the projected increase in global wildfire activity and the continued burning of fossil fuel. PyC is also increasingly produced from the industrial pyrolysis of organic wastes, which yields charred soil amendments (biochar).

Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN.

Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization.

Biosignatures in chimney structures and sediment from the Loki's Castle low-temperature hydrothermal vent field at the Arctic Mid-Ocean Ridge.

We investigated microbial life preserved in a hydrothermally inactive silica–barite chimney in comparison with an active barite chimney and sediment from the Loki's Castle low-temperature venting area at the Arctic Mid-Ocean Ridge (AMOR) using lipid biomarkers. Carbon and sulfur isotopes were used to constrain possible metabolic pathways. Multiple sulfur (dδ34S, Δ33S) isotopes on barite over a cross section of the extinct chimney range between 21.

Stable isotope analysis of organic carbon in small (µg C) samples and dissolved organic matter using a GasBench preparation device.

The stable isotopes of organic matter can provide valuable information on carbon cycling dynamics, microbial metabolisms, and past climates. Since bulk measurements may mask dynamic changes to critical portions of the organic pool, researchers are increasingly isolating individual compounds for isotopic analysis. The amount of carbon isolated is frequently small, requiring specialized equipment for its analysis.