Jill Mcdermott

• PhD
• Professor (Associate) at Lehigh University

The nature of deep-sea hydrothermal systems is commonly inferred from physicochemical plume characteristics and seafloor observations, as was the case for the 'Polaris' site on the ultraslow-spreading Gakkel Ridge, Earth's northernmost hydrothermal system. Initial reports showing temperature and turbidity anomalies in its hydrothermal plume combine...

Fissures and faults provide insight into how plate separation is accommodated by magmatism and brittle deformation during crustal accretion. Although fissure and fault geometry can be used to quantify the spreading process at mid‐ocean ridges, accurate measurements are rare due to insufficiently detailed mapping data. Here, fissures and faults at t...

In isolated fracture networks in the Precambrian Shield, long-term water and rock interactions produce saline anoxic fluids that host extant microbial communities deep within the continental subsurface. Light and oxygen (O2) are absent in these environments. Thus, chemotrophic organisms inhabiting these systems rely on anaerobic reactions for energ...

Metabarcoding analysis of environmental DNA samples is a promising new tool for marine biodiversity and conservation. Typically, seawater samples are obtained using Niskin bottles and filtered to collect eDNA. However, standard sample volumes are small relative to the scale of the environment, conventional collection strategies are limited, and the...

Comprehensive knowledge of the distribution of active hydrothermal vent fields along midocean ridges is essential to understanding global chemical and heat fluxes and endemic faunal distributions. However, current knowledge is biased by a historical preference for on-axis surveys. A scarcity of high-resolution bathymetric surveys in off-axis region...

The compositions of hydrothermal fluids in back-arc basins (BABs) can be affected by the influx of magmatic fluids into systems that are dominated by reactions between basement rocks and seawater-derived fluids. The East Scotia Ridge (ESR) in the Scotia Sea hosts such hydrothermal systems where the role of magmatic fluid influx has not yet been add...

Significance Hydrothermal fluid geochemistry exerts a key control on subseafloor microbial community structure and function. However, the effects of microbial metabolic activity, thermal decomposition of biomass, and abiotic reactions on geochemistry remain unconstrained. Depletions in molecular hydrogen and enrichments in methane in submarine hydr...

Abstract Explosive volcanic eruptions lead to ash deposition and subsequent leaching of contaminants into soils or surface water, impacting flora and fauna, including human health. This study determined the control of ash surface area and chemical composition on ash dissolution rates. Fresh, unhydrated ash samples from four contrasting volcanoes we...

In 2015, the deepest high-temperature hydrothermal vents in the Pacific Ocean (3,700 m) were discovered in a sediment-covered pull-apart basin along the Pescadero Transform Fault in the Gulf of California. Biological communities were observed thriving among the carbonate chimney structures (Figure 1; Goffredi et al., 2017). As a result of their str...

Hosted in basaltic substrate on the ultra-slow spreading Mid-Cayman Rise, the Piccard hydrothermal field is the deepest currently known seafloor hot-spring (4957-4987 m). Due to its great depth, the Piccard site is an excellent natural system for investigating the influence of extreme pressure on the formation of submarine vent fluids. To investiga...

Hot-spring fluids emanating from deep-sea vents hosted in unsedimented ultramafic and mafic rock commonly contain high concentrations of methane. Multiple hypotheses have been proposed for the origin(s) of this methane, ranging from synthesis via reduction of aqueous inorganic carbon (∑CO2) during active fluid circulation to leaching of methane-ric...

Little is known about evolutionary drivers of microbial populations in the warm subseafloor of deep-sea hydrothermal vents. Here we reconstruct 73 metagenome-assembled genomes (MAGs) from two geochemically distinct vent fields in the Mid-Cayman Rise to investigate patterns of genomic variation within subseafloor populations. Low-abundance populatio...

We show that fluid volumes residing within the Precambrian crystalline basement account for ca 30% of the total groundwater inventory of the Earth (> 30 million km³). The residence times and scientific importance of this groundwater are only now receiving attention with ancient fracture fluids identified in Canada and South Africa showing: (1) micr...

In 2014 and 2016, RV Polarstern expeditions examined two hydrothermally active areas on the Arctic Gakkel Ridge that had been located during the AMORE Expedition in 2001. We report on results of ship-based bathymetry as well as deep-tow visual and sonar survey data collected with the new Ocean Floor Observation and Bathymetry System (OFOBS). The Au...

During the 2016 RV Polarstern expedition exploring the axial volcanic Gakkel Ridge, we employed CTD casts to identify the source and dispersion characteristics of a hydrothermal plume at 87°N, 55°30’E, first identified by the 2001 AMORE expedition. We collected buoyant plume water samples characterized by pronounced Eh and potential temperature ano...

Supplementary Figures 1-6, Supplementary Tables 1-4 and Supplementary References

Fig. S1. Map of Caribbean Sea, with blue diamond indicating the location of the Mid‐Cayman Rise (inset). Von Damm and Piccard hydrothermal vent fields are shown in white diamonds. Fig. S2. ROV pictures of vent fluid sampling at selected vent site locations. (A) Old Man Tree at Von Damm; (B) Shrimp Hole at Von Damm; (C) Shrimp Gulley at Piccard, Be...

Warm fluids emanating from hydrothermal vents can be used as windows into the rocky subseafloor habitat and its resident microbial community. Two new vent systems on the Mid-Cayman Rise each exhibit novel geologic settings and distinctively hydrogen-rich vent fluid compositions. We have determined and compared the chemistry, potential energy yieldi...

This thesis examines the controls on organic, inorganic, and volatile species distributions in hydrothermal fluids venting at Von Damm and Piccard, two recently discovered vent fields at the ultra slow spreading Mid-Cayman Rise, Earth's deepest mid-ocean ridge. A wide variety of possible temperatures and substrates for fluid/rock reaction exist at...

Significance Arguments for an abiotic origin of organic compounds in deep-sea hot springs are compelling because of their potential role in the origin of life and sustaining microbial communities. Theory predicts that warm H 2 -rich fluids circulating through serpentinizing systems create a favorable thermodynamic drive for inorganic carbon reducti...

To make progress in understanding the origin of life, we require a deeper understanding of abiotic organic synthesis in geological systems. One way to obtain new information is to explore environments on the modern Earth that contain evidence of abiotic organic synthesis. Hydrothermal vents can serve as analogues of early Earth environments, and th...

Multiple sulfur isotopes were measured in metal sulfide deposits, elemental sulfur, and aqueous hydrogen sulfide to constrain sulfur sources and the isotopic systematics of precipitation in seafloor hydrothermal vents. Areas studied include the Eastern Manus Basin and Lau Basin back-arc spreading centers and the unsedimented basalt-hosted Southern...

Significance Simple alkyl thiols such as methanethiol are widely speculated to spontaneously form in seafloor hot spring fluids and are implicated in facilitating the emergence of protometabolism and microbial life in early Earth hydrothermal systems, the complexation of hydrothermally derived metals, and as fuels for microbial ecosystems. Existing...

Chemoautotrophic production in seafloor hydrothermal systems has the potential to provide an important source of organic carbon that is exported to the surrounding deep-ocean. While hydrothermal plumes may export carbon, entrained from chimney walls and biologically rich diffuse flow areas, away from sites of venting they also have the potential to...

The multiple sulfur isotope systematics of hydrothermal fluids and associated sulfide mineral deposits collected in 2006 in the eastern Manus Basin, Papua New Guinea, provide an opportunity to better understand the processes of mineral precipitation, pore fluid composition, chemosynthetic energy sources, and metal-rich ore deposition in a felsic-ho...

Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global Mid Ocean Ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultra-slow spreading ridges which were the last to be demonstrated to host high-temperature venting, but may host systems particularly rele...

Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global Mid Ocean Ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultra-slow spreading ridges which were the last to be demonstrated to host high-temperature venting, but may host systems particularly rele...

We present the first systematic characterization of the extent and distribution of hydrothermal activity along the previously unexplored Mid-Cayman Rise, Earth's deepest mid-ocean ridge as part of a NASA-funded ASTEP program.

The Mid-Cayman Rise, an isolated deep mid-ocean ridge, hosts all 3 known submarine vent-types AND the deepest vents known, making it an ideal natural laboratory for continuing studies of astrobiology, evolutionary biology and the origins of life.

We report the first systematic exploration for and characterization of hydrothermal vents and vent ecosystems on the short (~110 km), deep (> 5000 m), ultra-slow-spreading (<20 mm yr-1) Mid-Cayman Rise in the Caribbean Sea. This work was carried out aboard the RV Cape Hatteras in October-November 2009 as part of the ChEss Project of the Census of M...

Hydrothermal fluids circulated through mid-oceanic ridges provide the necessary chemical energy for biological reactions in the thriving deep biosphere (1). In order to refine hydrothermal flux estimates and determine the implications for macro- and microbiological communities, the processes controlling chemical composition of hydrothermal fluids m...

The Ridge2000 Integrated Study Site (ISS) on the East Pacific Rise (EPR), 9-10° north latitude was impacted by several volcanic eruptions in the months preceding April 2006. In June 2006 during the RESET06 cruise (AT15-6) we used the DSV Alvin to collect samples from the hydrothermal system at this site from M Vent in the north (9°°50.7'N) to L Ven...