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Seasonal dynamics and allometric considerations of feeding and food processing for macrozooplankton in the northeast Pacific OceanEllis, Steven G. 26 July 1991 (has links)
Graduation date: 1992
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Tectonic, sedimentary, and volcanic processes associated with rifting of the central Bonin island arcBrown, Glenn R January 1991 (has links)
Three folded maps in pocket. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1991. / Includes bibliographical references. / Microfiche. / x, 173 leaves, bound ill. (some col.), maps 29 cm
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EASTERN EQUATORIAL PACIFIC PRODUCTIVITY VIA TWO GEOCHEMICAL PROXIESRobertson, Angela K. 16 March 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Drivers that influence oceanic productivity are not clearly constrained. However, sea level changes during glacial cycles have been proposed as a potential driver for productivity variations observed over warm and cold climate periods. In order to determine this, additional oceanic paleoproductivity data collection is necessary to estimate the ocean’s feedback in response to a dynamic climate. The eastern equatorial Pacific (EEP) is an ideal site for productivity studies due to its high levels of nutrients and deep upwelling. This research examines the phosphorous and barite geochemisty of four EEP sites while also comparing the sites’ glacial and interglacial productivity variations to the geochemistry and productivity results of an independent central equatorial pacific site.
Phosphorus and other elemental data were collected from sites 845, 848, 849, and 853 (ODP Leg 138). Using a Ba/Ti and P/Ti proxy (“excess” proxies), distinct productivity variations during glacial and interglacial periods were observed. While the age model for these sites has been estimated, the observed variations more than likely agree with high productivity during glacial periods and lower productivity during interglacial periods. Central equatorial Pacific cores RR0603-03TC and RR0603-03JC (IODP site survey cruise for Proposal 626) have been used as a reference for geochemical concentration parameters, as well as a comparison tool for productivity variations among the central and eastern sites. The central equatorial geochemistry results provided support for sea level changes driving paleoproductivity variations. The similar variation patterns displayed by the EEP’s geochemical data in this research could provide additional support for this hypothesis.
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Correlations of sea surface height and solid earth tides with seismicity in the equatorial Pacific Ocean : a GIS approachZennaro, Barbara 17 February 2006 (has links)
In the equatorial Pacific Ocean, earthquakes are used as an indicator of tectonic stress
for normal faults in the Galapagos Spreading Center, transform faults along the East
Pacific Rise and thrust faults in the Middle American subduction zone. Linkages between
seafloor tectonic processes and oceanographic and lunar conditions were explored using
time-series cross-correlation analyses on two different time scales.
Data for earthquakes in the eastern tropical Pacific study area are obtained using the
hydrophone arrays of the NOAA-VENTS Program. Hydroacoustic monitoring (listening
to underwater sounds) provides scientists with a detailed dataset that includes even small
earthquakes, starting as low as magnitude 0.6, that are not perceived by land-based
seismographs. Data for sea surface heights (SSH) consist of two different datasets. On a
moon's quarter time scale, SSH data used to investigate the influence of the earth tide and
changes in oceanic conditions were remotely acquired by the altimeter on board the
TOPEX/Poseidon (T/P) satellite. SSH data used to investigate the influence of the ocean
tides were obtained from the Tidal Model Driver (Padman and Erofeeva 2003), that
predicts SSH for locations every hour. The Geographic Information System (GIS) was
used for the visual display of the data and to compute basic descriptive statistics. A lab-book
was created for the educational-outreach section of this work, explaining step by
step how GIS has been used.
Significant results show correlations between normal faults and ocean tides and
between the thrust fault and earth tides. Also, the Quebrada and the Discovery transform
faults show high correlation of earthquake events, suggesting that at such temporal and
spatial resolution, the plate moves as a rigid block. / Graduation date: 2006
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Oceanographic factors affecting the catchability of Pacific Ocean perch, Sebastes alutus (Gilbert)Scott, Beth Emily January 1990 (has links)
A main concern in fisheries science has been to identify an accurate index of fish abundance. An underlying paradigm in the science has been that the amount of effort (calculated in hours and standardized for boat size) spent fishing was the best variable to be used to account for the variation in catches. The use of the ratio, catch per unit of effort (cpue), assumes that variations in fish abundance are due to human-controlled processes above the ocean's surface. It does not account for variation due to oceanographic processes that affect fish behaviour and movement patterns below the ocean's surface.
This study investigated the possibility that oceanographic factors such as temperature, salinity and depth could have effects on the variations observed in the apparent abundance of a demersal rockfish, Pacific Ocean Perch (Sebastes alutus. Gilbert). Simultaneous monitoring of physical variables and fish abundance estimation was achieved by attaching oceanographic equipment to the fishing gear of commercial vessels, monitoring the acoustic equipment and sampling the fish catch. It was found that Perch prefer a temperature range from 6.7 °C, down to at least 4.8 °C and that their movement patterns are linked to the movement of these temperatures by coastal wind patterns. Perch prefer areas with steep bathymetry, characterized by frontal activity due to interactions between the local bathymetry and tidal currents.
Concerns that sampling only from highly successful commercial vessels may have biased abundance estimates, prompted the analysis of historical records of fish catch and government research surveys. Analyses between different boat sizes, different areas and different seasons from the original historical data base and a corrected subset revealed that it was mainly differences between areas that was responsible for the biasing of estimates. Deeper areas predictably produced more fish for all sizes of boats, but were fished more often by the larger boats used in the study. Therefore the field abundance estimates are likely to be biased towards areas of larger perch concentrations. / Science, Faculty of / Zoology, Department of / Graduate
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The chemistry of iron and manganese in submarine hydrothermal systemsHudson, Andrew G January 1980 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1980. / Microfiche copy available in Archives and Science. / Bibliography: leaves 79-80. / by Andrew G. Hudson. / M.S.
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Numerical simulation of landslide-generated tsunamis with application to the 1975 failure in Kitimat Arm, British Columbia, CanadaSkvortsov, Andrey 10 April 2008 (has links)
No description available.
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Sedimentation within the Cocos Gap, Panama BasinDowding, Lynn Gretton 04 November 1975 (has links)
The Cocos Gap is a deeper portion, or saddle, of the Cocos
Ridge and forms part of the western boundary of the Panama Basing
It is probably typical of saddles within most submarine ridges, In
order to determine the mechanisms controlling sediment dispersal,
the nature and sources of the sediments at 23 core locations were
defined by hydrodynamic size separation (> 63, 2- 63, <2 micron) and
microscopic or X-ray diffraction analysis of the individual fractions.
In addition, calcium carbonate, organic carbon, opal and quartz
determinations were made for the total sediment.
The silt sized fraction was resolved into eight textural modes,
The coarse modes reflect the progressive breakage and winnowing of
the corase fraction (foraminifera) under the influence of bottom
currents and gravity. Above 2000 m mechanical breakdown, winnowing
and relocation by bottom currents mask the effects of depth related
dissolution of the carbonate fraction, Intermediate modes in general
represent a transitional facies with both biogenic and terrigenous influences,
while the finest modes characterize a distal regime of clay
deposition, The clay fraction is amorphous material with very low
percentages of well crystallized clays. Three main sources and
transport paths were recognized, including one associated with the
circulation of the Panama Basin.
Sedimentation within the Gap is controlled by local processes,
predominantly the interaction between tidally induced intensification
of bottom water flow and directional (thermohaline) flow. The steep'
ness of the sea floor slope is a major factor controlling the efficiency
of winnowing of the sediment away from certain higher elevations
(biogenic source areas) to the sheltered parts and flanks of the ridge.
Superimposed upon this sediment dispersal is the influx of terrigenous
material carried by directional bottom currents that operate as
postulated upper and lower contour currents along the flanks of the
ridge.
The crest of the Cocos Gap acts as a catchment area for the
biogenic components, while the adjacent more sloping region, the
sub-plateau, acts as a source area. The extreme breakage of the
foraminifera is most likely a function of the tidally induced intensification
of the bottom water flow, characteristic of many shallow ridges,
and is probably most significant in the subplateau. Hydrographic
data indicates that there is no significant transport of bottom water
across the Cocos Gap into the Panama Basin, but downslope transport
of carbonate and siliceous fragments and minerals from the Gap into
the basin is associated with cyclical tidal bottom water flow. / Graduation date: 1976
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Cascadia channel : the anatomy of a deep-sea channelGriggs, Gary B. 08 November 1968 (has links)
Graduation date: 1969
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Seasonal distribution of nutrients off the coast of Oregon, 1968Ball, David Stephen 16 March 1970 (has links)
Phosphate, silicate and nitrate concentrations in the sea off
the coast of Oregon were determined to study their seasonal distribution
patterns. The water samples were collected monthly along the
east-west hydrographic line off Newport, Oregon, from the shore to
165 miles (310 km) offshore. The samples were analyzed by both a
Technicon Autoanalyzer® and by manual methods.
Phosphate in January was greater than 0.5μM at the surface,
increasing to a 3.3μM maximum at 1000m. A phosphate maximum
occurred at 1000m throughout the year. With the onset of photosynthetic
activity, there was a general decrease in surface concentrations.
Concentrations decrease to less than 0.1μM in October
with surface concentrations increasing in November and December,
reaching a maximum in January.
Silicate concentration was approximately 170μM at 2600m during
the entire year. In January, surface silicate increased from less than
5μM offshore to 13μM nearshore; a weak silicate minimum was
observed at a depth of 60m offshore and at 5m near the coast. In
March nearshore surface concentrations were greater than 15μM due
to increased coastal river runoff; the silicate concentrations of
Oregon coastal rivers were 150-250μM. In July, a pronounced minimum
occurred at 40-50m depth, where the concentration was less
than 2μM. Summer surface concentrations were less than 2M offshore,
increasing to 40μM nearshore as a result of coastal upwelling.
Surface concentrations in October were generally less than 5FIM along
the Newport hydrographic line with increased near shore concentrations
due to river runoff.
The nitrate maximum of 40-45μM existed at 1000- 1200m. In
January surface concentrations ranged from 3μM offshore to 6μM
nearshore. March values were lower, ranging from 11μM offshore to
5μM nearshore at NH-3 (6 km). In July patches of nitrate-free water
were observed at 40-50m depth offshore, disappearing at 25 miles
(46 km) off the coast, at station NH-25, as a result of the influence
of upwelled and nitrate containing water. Late in October, nitrate
concentrations were higher, 5-6μM, near the coast, and dropping to
less than 0.1μM offshore. Patches of nitrate-free water were found
from May to November.
The existence of nitrate-free water near the surface indicated
that the feature was formed by the photosynthetic activities of phytoplankton.
The formation of the silicate minimum and oxygen
maximum below or near the bottom of the Columbia River Plume
during summer months indicated intense photosynthetic activity.
Neither preformed phosphate nor preformed nitrate changed
with depth below the layers of active photosynthetic processes. Preformed
phosphate was generally 1.0-1.2μM below 200m with variation
occurring in surface waters. For surface values, 1.2μM, the highest
of the year, was observed in July in upwelled water; 0.4μM, the
lowest, also occurred in July within the influence of the Columbia
River Plume.
The vertical distribution of preformed nitrate seemed to be
random and may have reflected analytical techniques. The range was
between 5 and 10μM with a maximum at 12μM. The 5μM values were
found at approximately 200m with a maximum observed at 1000m
deep. The highest surface values of preformed nitrate, 2.0-5.0μM,
were observed in January and the lowest, 1.0-1.5μM, in July. March
and October values were between the above extremes (1.1-2.0μM). / Graduation date: 1970
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