It has been recognized since the 1950's that radioisotopic disequilibrium between naturally occurring parent-daughter isotope pairs in seawater can provide information on the rate of processes segregating them. In the surface ocean, the U-238:Th-234 parent-daughter pair tends to display measurable disequilibrium that is attributable to the effects of scavenging on...
Subsurface hydrothermal activity dominates the heat and salt budgets of the deep water column in Crater Lake, Oregon. From a time series of conductivity-temperature-depth data and data from a thermistor chain mooring, we estimate that the net hydrothermal heat flow is ~1 W m⁻² and the corresponding salt flux is...
We present evidence for pore water flow through the sediment of Crater Lake, Oregon based on systematic variations in pore water chemical compositions and thermal gradients. Pore water was extracted from sediment by centrifugation and diffusive exchange using a gravity corer deployed from a surface vessel and a box corer...
To constrain the fluxes of methane (CH4) in the water column above the accretionary
wedge along the Cascadia continental margin, we measured methane and its stable carbon
isotope signature (δ¹³C-CH₄). The studies focused on Hydrate Ridge (HR), where
venting occurs in the presence of gas-hydrate-bearing sediments. The vent CH₄ has...
Methane reservoirs and seeps are an active component
of the continental margin carbon budget and represent a
poorly characterized pathway for reduced carbon cycling
and methane input to the atmosphere. Active gas seeps from
three shelf settings on the Cascadia Continental Margin off
Oregon and Northern California contain nearly pure...
Submersible investigations of the Cascadia accretionary
complex have identified localized venting of methane gas
bubbles in association with gas hydrate occurrence. Acoustic
profiles of these bubble plumes in the water column in the
vicinity of Hydrate Ridge offshore Oregon provide new
constraints on the spatial distribution of these gas vents...
Plankton tows from the northern California Current constrain biological and physical
influences on living planktonic foraminifera. In this region, the dominant factors controlling the
size and distribution of symbiotic and asymbiotic species are light and food. Food decreases offshore.
Light, needed for symbiont photosynthesis, increases offshore as water turbidity lessens....
Active inputs of thermally and chemically enriched fluids at the bottom of Crater Lake create small vertical and horizontal heterogeneities in the deep-lake temperature and salt distribution. Using an internally recording CTD and a precise definition for salinity as a function of in situ conductivity and temperature, we assess the...
Small temporal and spatial variations in the distribution of dissolved oxygen in Crater Lake, Oregon, are used to estimate the mean age of the lake’s deep water, the flux of labile organic carbon to the deep lake, and the influence of hydrothermal activity on the concentration of dissolved oxygen within...
This study assesses the role of the atmospheric dry fallout as a source of new nitrogen and phosphorus to the surface Levantine seawater. Leaching experiments of inorganic nitrogen (LINO-3, LINH+4) and phosphorus (LIPO4), using SE Mediterranean surface seawater, were performed on 41 aerosol (hereafter dust) samples collected on Whatman 41...
