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...
We examined the characteristics of biological patches at four different locations to assess the relationship of patch vertical scale, amplitude, and persistence. In contrast to patches of larger animals, we found that the majority of coherent aggregations of plankton at each site were vertically compressed, with most smaller than 5m...
This thesis investigates the behavior of major inorganic nutrients (P, N, Si), trace metals (Mn, Fe), and alkaline-earth metals (Ba) within Tillamook Bay over seasonal cycles and under a range of river discharge conditions from October 1997 through December 1999. Located in the Pacific Northwest region, Tillamook Bay is an...
The objective of this study was to compare two techniques for estimating benthic fluxes of nutrients (nitrate, phosphate, and silicic acid) and Ge/Si flux ratios. In situ flux chambers were deployed, and cores were collected and incubated at 9 sites along the California margin in July 2001. Both techniques were...
The isotopic composition of the dissolved inorganic carbon (DIC) collected at sites of active methane discharge on Hydrate Ridge, Oregon, reveals anaerobic methane oxidation mediated by bacteria, with δ13CDIC reaching values as low as –48‰ in the upper 4 cm of the sediment. In spite of the high sulfide levels...
Benthic chamber measurements of the reactants and products involved with biogenic matter diagenesis (oxygen, ammonium, nitrate, silicate, phosphate, TCO₂, alkalinity) were used to define fluxes of these solutes into and out of the sediments off southern and central California. Onshore to offshore transects indicate many similarities in benthic fluxes between...
Geophysical and biogeochemical processes associated with fluid venting from active and passive continental margins will receive significant scientific and economic attention
into the next century and are of major societal relevance. An important unknown among these interrelated processes is the role played by methane gas hydrates, at and below the...
A massive release of methane on the Cascadia Hydrate Ridge was documented
during a ROPOS program in August 1998, consistent with previously reported
observations in 1996. An extensive survey of the seafloor revealed that the
seeps lie within a narrow band trending 109 degrees. This feature parallels larger
mounds imaged...
A study was conducted to determine the heat transfer characteristics
of pin finned heat sinks in natural convection. Three pin
diameters were studied: 0.238 cm, 0.318 cm and 0.396 cm. The pins
were attached to the base in two arrangements, triangular and
rectangular, forming a horizontal array. Pin spacing was...
Cores taken from the ridge areas of the Gorda-Juan de Fuca
plate have a sedimentation rate that is appropriate for the study of
late Quaternary stratigraphy. An analysis of the clay and silt
mineralogy of the cores using X-ray diffraction methods and by
noting changes in the foraminiferan-radiolarian abundances in...