While bubble plumes have been acoustically imaged in the water column above marine gas
hydrate deposits in many studies, little is known about the temporal variation in plume intensity. In
July 2008, we conducted surveys using 3.5 and 12 kHz echosounders and a 75 kHz acoustic Doppler
current profiler (ADCP)...
Subduction zone earthquake and tsunami hazards affect tens of millions worldwide and the recurrence of these disasters can be evaluated with paleoseismic techniques, because earthquake cycles (and their supercycles) typically span many millennia. In these three chapters, I discuss a suite of analyses I use to evaluate the sedimentary record...
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, I es mate that slopes become unstable when a seismic
load of <0.2 g is imparted. Using infi nite
Carbonate communities:The activity of anaerobic methane oxidizing microbes facilitates
precipitation of vast quantities of authigenic carbonate at methane seeps. Here we demonstrate
the significant role of carbonate rocks in promoting diversity by providing unique habitat
and food resources for macrofaunal assemblages at seeps on the Costa Rica margin
(400–1850 m)....
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Carbonate at Costa Rica Methane Seeps
Levin, L. A., Mendoza, G. F., Grupe, B. M., Gonzalez, J. P., Jellison
The atmospheric flux of methane from the oceans is largely mitigated through microbially
mediated sulphate-coupled methane oxidation, resulting in the precipitation of authigenic
carbonates. Deep-sea carbonates are common around active and palaeo-methane seepage,
and have primarily been viewed as passive recorders of methane oxidation; their role as active
and unique...
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pieces of
carbonate (B5 cm diameter pieces, B300 g total mass) with
2mM 15NH4Cl and 0.44mM CH4 (50% 13CH4
We investigated dissolved methane distributions along a 6 km transect crossing active seep sites at 40 m water depth in the central North Sea. These investigations were done under conditions of thermal stratification in summer (July 2013) and homogenous water column in winter (January 2014). Dissolved methane accumulated below the...
Hydroacoustic data document the occurrence of 5 flare clusters and several single flares from which bubbles rise through the entire water column from an active seep site at 40 m water depth in the central North Sea. We investigated the difference in dissolved methane distributions along a 6 km transect...