Amy Gartman, PhD

No abstract available.

Metal sulfide minerals exist in several marine environments and are in thermodynamic disequilibrium with oxygenated seawater from the time of their formation. Oxidation is both ubiquitous and heterogeneous, as observational and experimental evidence demonstrates that sulfide minerals may oxidize completely on decadal timescales (hydrothermal plumes) or incompletely in billions of years...

Polymetallic sulfide (PMS) deposits produced at hydrothermal vents in the deep sea are of potential interest to miners. Hydrothermally active sulfide ecosystems are valued for the extraordinary chemosynthetic communities that they support. Many countries, including Canada, Portugal, and the United States, protect vent ecosystems in their Exclusive Economic Zones. When hydrothermal...

Chemical, physical and biological processes in hydrothermal plumes control the flux of elements from hydrothermal vents to the global oceans. The timescales of these processes range from less than a second, as the hydrothermal fluid mixes with seawater at the seafloor, to decades, as the plume disperses over thousands of kilometers. Integrating hydrothermal geochemistry throughout the...

Hydrothermal activity results in the formation of hydrothermal mineral deposits, including seafloor massive sulfide deposits, at oceanic spreading ridges, arcs, and back-arcs. As hydrothermal systems age, the mineral deposits eventually become severed from the heat source and fluid-flow pathways responsible for their formation and become extinct. The timescales and processes by which...

Interactions among microorganisms and their mineralogical substrates govern the structure, function, and emergent properties of microbial communities. These interactions are predicated on spatial relationships, which dictate metabolite exchange and access to key substrates. To quantitatively assess links between spatial relationships and metabolic activity, this study presents a novel...

Precipitation processes in hydrothermal fluids exert a primary control on the eventual distribution of elements, whether that sink is in the subseafloor, hydrothermal chimneys, near-field metalliferous sediments, or more distal in the ocean basin. Recent studies demonstrating abundant nanoparticles in hydrothermal fluids raise questions as to the importance of these nanoparticles...

Deep-sea hydrothermal vents are a significant source of dissolved metals to the global oceans, producing midwater plumes enriched in metals that are transported thousands of kilometers from the vent source. Extensive particle precipitation upon emission of hydrothermal fluids, due to temperature and pH changes during mixing with ambient seawater, controls metal speciation and the...

Ferromanganese (FeMn) crusts from Mendeleev Ridge, Chukchi Borderland, and Alpha Ridge, in the Amerasia Basin, Arctic Ocean, are similar based on morphology and chemical composition. The crusts are characterized by a two- to four-layered stratigraphy. The chemical composition of the Arctic crusts differs significantly from hydrogenetic crusts from elsewhere of global ocean by high mean...

Mineral formation in the modern oceans can take place over millions of years as a result precipitation from ambient ocean water, or orders of magnitude more rapidly from hydrothermal activity related to magmatic and tectonic processes. Here, we review associations between transform faults and related fracture zones and marine minerals. We define marine transform faults as strike-slip or...

Gold colloids occur in black smoker fluids from the Niua South hydrothermal vent field, Lau Basin (South Pacific Ocean), confirming the long-standing hypothesis that gold may undergo colloidal transport in hydrothermal fluids. Six black smoker vents, varying in temperature from 250 °C to 325 °C, were sampled; the 325 °C vent was boiling at the time of sampling and the 250 °C fluids were...

Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, HLY1202). We determined mineral and chemical compositions of the crusts and nodules and...