The marine climate of the Galapagos is spatially and seasonally
heterogeneous. A taxonomically comprehensive study of Galapagos zooplankton has
never been done. This study is an initial effort to establish the distribution and
community structure of zooplankton in the Archipelago. I collected zooplankton
samples by vertical tows over the Galapagos...
Research on the application of soluble, metal chelates for
water tracing using thermal neutron activation analysis for tracer
determination has led to the development of several tracers with
promising solution stabilities (conservative behavior) and determination sensitivities. The solution stabilities of the ethylenediamine
tetraacetic acid (EDTA) and the diethylenetriamine pentaacetic acid...
Discrete layers of phytoplankton and zooplankton were observed over the Oregon continental shelf in summer and fall of 2001 and summer 2002 using optical and acoustical technologies and a pump sampling system. Layers of phytoplankton had steep vertical gradients which were associated with gradients in density and local peaks in...
Sedimentary sections recovered during the Deep Sea Drilling Project and the Ocean
Drilling Program provide the opportunity to study the evolution of Neogene climate at high
resolution overtime periods spanning millions of years. Two components of the paleodlimatic
system, eastern equatorial Pacific carbonate sedimentation and global ice volume, were
examined...
In eastern boundary current upwelling ecosystems, mesoscale circulation features such as eddies and upwelling filaments play a prominent role in the transfer of water and the associated plankton from the productive nearshore to the oligotrophic deep sea. The relationship between mesoscale circulation, zooplankton distributions, and the across-shelf transport of coastal...
A benthic microbial fuel cell (BMFC) is an electrochemical device that
generates current from the redox gradient at the sediment-water interface. Early
prototypes had anodes buried in anoxic sediments and cathodes in overlying water.
The BMFCs described in this dissertation are based on a chamber design that enables
the use...
The objective of this research was to improve our understanding of how
changes in the environment affect ecological processes. Change detection is often
confounded by the large variation found in ecological data due to the difficulty of
finding replicates in nature. Intertidal communities were chosen for studies of biophysical
interactions...
Motivated by observations of locally enhanced sea level variability near steep
topographic slopes in regions of strong time-mean flows, effects of zonal ridge topography
on zonal oceanic jet flow are investigated. Unstable wave properties and the
dynamics of eddy-mean flow interaction are evaluated as a function of topographic
geometry using...
Two separate studies on the distribution of gammarid amphipods in the bathyal and abyssal benthic environments demonstrated that different assemblages could be found at a single depth over distances on the order of 100 kilometers. These studies evaluated changes in the species composition and relative abundance of the amphipod assemblage...
Instability and turbulence in sheared, salt-fingering favorable stratification are studied
using three-dimensional direct numerical simulations (DNS). Salt-fingering favorable
stratification is gravitationally stable, because the unstable vertical gradient of salinity
is stabilized by temperature (warm, salty over cool, fresh water-masses). Salt-fingering
instability can occur at the interface of these different water-masses....
The character of the primary seismic wave in the
range of distances between 100 and 600 km is affected by
such factors as the nature of the source, exponential
attenuation, crustal structure, type of wave propagation,
recording site geology and instrument response. The
first arrivals from the GNOME and SHOAL...
Short-term changes in the distribution, surface to 10 meters, of
phytoplankton-associated trace metals (Fe, Mn, Cr, Zn, Co, Ni, and
Cu) were studied in the near-shore waters off Humboldt Bay,
California, through the summer of 1971. The depth distribution of
phytoplankton-associated trace metals was related to local hydrography.
During periods...
Tide-topography coupling is important for understanding surface-tide energy loss, the intermittency of internal tides, and the cascade of internal-tide energy from large to small scales. Although tide-topography coupling has been observed and modeled for 50 years, the identification of surface and internal tides over arbitrary topography has not been standardized....
Analogous to ocean surface waves, waves in the ocean interior also experience steepening, breaking, and dissipation as they approach the coastline. Much less is known about this internal beach. In this work, extensive moored Acoustic Doppler Current Profiler and temperature/salinity data together with optical remote sensing are combined to describe...
The time-averaged velocity field in the North Pacific was estimated in two
sets of inverse calculations. The planetary geostrophic equations were the basis for
dynamical models of the flow in each case. The inverse estimates of the circulation
were obtained by minimizing a positive-definite cost function, which measured the
inconsistency...
The inherent and apparent optical properties of different ocean regimes are the basis for all optical remote sensing of the ocean. Ecological information derived from remote sensors therefore relies on having a detailed understanding of how particulate backscattering and absorption contribute to the bulk optical signal. The absorption
characteristics of...
The local and remote sources of variability of the South Atlantic Ocean are investigated using a set of numerical experiments and satellite data. A global, eddy-permitting, numerical simulation is analyzed to investigate the dynamical links between the Antarctic Circumpolar Current (ACC) and the Malvinas Current (MC). The model results indicate...
The principal salinity extrema and extremum surfaces of the
world ocean are described by the analysis and plotting of data from
885 hydrographic stations in the three major oceans, the Southern
Ocean, and the American Mediterranean Sea. The distributions of
salinity, temperature, depth, and density along the extremum surfaces,
plotted...
A systematic study of highly branched isoprenoids (HBI) was carried out in
suspended particulate material (SPM) and Washington coastal sediments to determine
their origin and fate. SPM collected at 10 m depth was filtered through Nitex
membranes. C₂₅ HBI were found only in the 1.2-40 μm range over the shelf....
When adult spawning and juvenile settling locations of marine fishes are
geographically separated, their early life history stages must rely on transport and
their own behavior to move them toward suitable habitats for successful recruitment
to the juvenile phase. Variations in climate may reduce the availability of spawning
and juvenile...
The physical characteristics of continental shelf waters off
Oregon during late winter and spring of 1975 are described and compared
with observations taken previously during summer. The currents
in winter are barotropic in the monthly means while in summer
the currents are baroclinic. Alongshore current fluctuations on the
time scale...
Volcanic rocks from hotspots and island arcs/backarcs typically have enriched trace
element and isotopic compositions that contain a contribution from subducted oceanic crust.
Isotopic and trace element data suggest that the enriched components in hotspot volcanism
are ancient subducted sediment and crust, and the enriched components in arc/backarc
volcanism are...
Using a linear quasi-geostrophic model of large scale spiraling flow and vertical density gradient in the eastern North Pacific, we evaluate the complex dispersion relationships for quasi-geostrophic waves. Our calculations indicate that the geostrophic circulation of the eastern North Pacific can locally convert potential energy to mesoscale kinetic energy on...
Precise in situ measurement of the spectral absorption and scattering coefficients in several regions has revealed patterns in the distribution of the inherent optical properties on spatial scales that were previously unobtainable. The precision of the measurements was found to be consistent and unbiased across a variety of oceanic regimes...
This thesis investigates the influence of early diagenesis on trace metal and
molybdenum isotope behavior in marine and lacustrine environments. Chapter one is a
synthesis of previous research in all the marine environments investigated, providing an
essential geochemical context for interpreting the observed behavior of Mo in these settings.
Chapter...
A criterion is defined to compare seasonal ice coverage in the
Greenland Sea for the years 1900-57, and the areal coverage is
graphed using the 1898-1913 average as a standard. The factors
wielding possible influence on short-term variations of the ice cover
are examined individually and their relative importance established....