<p> Primnoa resedaeformis is a deep-sea gorgonian coral with worldwide distribution and a lifespan of at least several hundred years. Recent work has suggested that it may be possible to obtain extended, high-resolution records of ambient oceanographic conditions from Primnoa skeletons. This thesis focuses on specimens recently collected live from the Northeast Channel, SW of Nova Scotia, from depths of 300-500m. </p> <p> Skeletal microstructure was examined as a prerequisite to geochemical sampling. Skeletons exhibit periodic growth at three distinct scales. Concentric annual rings throughout the skeleton, and sub-annual laminae in the horny axis, measure 200 +1-100 microns and 15 +1-10 microns, respectively. Fine-scale striae in the outer calcite cortex measure 1.5 +1-2 microns. The dark, gorgonin-rich portion of annual rings in the horny axis forms in winter, when currents in the NE Channel are most energetic. Growth in these animals is apparently tied to the passage of currents at seasonal, lunar and tidal frequencies. Annual ring widths in the horny axis could not be successfully cross-dated, however, a prominent dark ring that appears to have been formed in 1976 is present in several of the colonies examined. Prominent dark rings may serve as useful benchmarks in sclerochronology. </p> <p> Mg/Ca and Sr/Ca were measured by laser ablation ICP-MS in the predominantly calcite axial cortex. Across a 1.5°C gradient, Mg/Ca is positively related to temperature. Sr/Ca also increases with temperature, but this may be explained by the influence of Mg/Ca on Sr partitioning, rather than temperature. Near annual-resolution timeseries profiles of Mg/Ca are consistent within and among colonies having different growth rates. Conversion of Mg/Ca profiles to temperatures using a provisional calibration [Mg/Ca (mmollmol) = 4.88(+/-1.09) T (°C) + 70.92 (+/-6.79)] yields a range of values and trends that are consistent with the observational data. Mg/Ca in Primnoa, therefore, is a viable means of monitoring bottom-water temperatures. The North Atlantic Oscillation (NAO) is responsible for a significant component of inter-annual temperature variability in the Scotia-Maine region. Mg/Ca records from older corals could therefore provide extended proxy records of the NAO. </p> / Thesis / Master of Science (MSc)

The deep sea is the largest ecosystem on the planet, comprising more than 90% of the volume that life can inhabit, yet it is the least explored biome in the world. The deep sea includes the benthos, which makes up 91.5 % of all the seafloor globally, and the water column deeper than 200 meters. It hosts a wealth of ecosystems including deep-sea vents, seamount coral gardens, abyssal plains, high-productivity whale falls, and life even in the deepest trenches. We now understand that all of these ecosystems host a variety of habitats, each with their own ecology and unique species. These ecosystems and habitats- and their associated biodiversity- provide essential ecosystem services such as carbon sequestration, nutrient regeneration, microbial processes detoxification, fisheries provisioning, and many others. However, despite the uniqueness of these ecosystems and the importance of the services they provide, we still know far less about them than we do about their shallow water and terrestrial counterparts. In this dissertation, I contribute new insights about the patterns of biodiversity in the Pacific Ocean across a large geographic area, and across a wide range of depths. To that end, in Chapter 1, I have used one of the largest ocean exploration datasets to look for patterns of the abundance and diversity across the most common benthic invertebrate families found on Pacific seamounts: Anthozoa, Porifera, and Echinodermata across the Central and Western Pacific. In addition to quantifying the diversity and abundance of known taxa, I also documented patterns of as-of-yet unidentified taxa by region, depth, and deepwater feature (seamount shape). Building on patterns associated with seamount shape that were described in Chapter 2, I focused on the effect of seamount shape on the diversity and abundance of deep-sea coral communities in Chapter 3. The analysis presented in Chapter 3 provides strong support for the novel hypothesis that gross seamount morphology is a significant driver of community composition. In Chapter 4, I focused on a single seamount to investigate biodiversity and abundance of coral and sponge taxa on a finer spatial scale, examining the role of direction (N, S, E, W) on different flanks of a single equatorial seamount. This analysis yielded interesting consistent patterns of zonation on all sides of the seamount in terms of depth, but with differences in abundance patterns on each flank for individual taxa. Finally, in Chapter 5, I took a global perspective to investigate gaps in deepwater data, with the goal of determining what regions need further exploration to conclusively determine patterns of deep-sea biodiversity, which will be critical for determining the health of deepwater ecosystems under climate change conditions with increased exploitation pressure and cooccuring with increased conservation efforts. Merging Ocean Biogeographic Information System (OBIS) records with the largest collection of deep submergence dive records ever collected, I used proposed biogeographic provinces schema to identify areas with the least supporting data. Additionally, I coupled records from OBIS with climate change projections to identify the areas with the fewest number of biodiversity records that are likely to change the fastest under different IPCC projections. These areas of low number of records and high likelihood of change by the end of the century should become priority targets for future exploration. Taken together, this dissertation provides valuable insights and generates new hypotheses about patterns and drivers of deep-sea biodiversity, and puts forth recommendations for future research and exploration efforts.

Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies since the first lead-radium dating study on fish in 1982. The activity of radium-226 measurements ranged over 3 orders of magnitude (<0.001 to >1.0 dpm.g⁻¹). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.

The role of Serrivomer beanii in bathypelagic food webs is poorly known, but abundance and biomass estimates from the 2004 G.O. Sars MAR-ECO Expedition suggest it to have a high level of importance. MAR-ECO, a Census of Marine Life field project, has allowed us to increase our knowledge of S. beanii through spatial analysis, including the congeneric species Serrivomer lanceolatoides, and trophic analysis. Serrivomer beanii abundance and biomass exhibited a decreasing trend along the northern Mid-Atlantic Ridge from north to south. In terms of size, S. beanii was found to increase as distance from the ridge decreased, suggesting a topographic aggregation strategy. The diet of S. beanii consisted of crustaceans, cephalopods, and teleosts. The trophic results of this study reveal a likely "alternative" trophic pathway in the deep mid-North Atlantic, and perhaps other, bathypelagic ecosystems: higher trophic-level predators are supported by micronektonic invertebrates as primary prey. / by Megan E. Geidner. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

Thesis (MBA)--Stellenbosch University, 1984. / BACKGROUND AND OBJECTIVE: The chief sector of the South African fishing industry, demersal trawling is in a state of uncertainty that brings its competitiveness and long term developnent into question. The Hake (Merluccius capensis and Merluccius paradoxus) resource, which accounts for 70% of the landed catch, has finally started on the expected road to recovery and it is anticipated that this will proceed shortly for a nunber of years. During 1983 comfort was derived from the resulting rise in catch per unit effort rates and a significant improvement in the average size of fish landed. This, together with lower fuel prices and increased operating efficiences, enable the industry to operate at lower expenditure. Unfortunately, a second successive reflection of the T.A.C. (Total Allowable Catch ) of 12% in 1983 meant that gains in productivity were not fully reflected in reduced landed costs. This year (1984) the T. A. C. was increased by 4,8% which only marginally improves the already poor situation. More serious difficulties can be traced to adverse market developments. The price of fish has fallen in real terms (see Table 1.1 below) over a number of years. However, in 1983, the industry experienced a startling fall in prices, the severity of which may be gauged from the fact that actual prices realised were roughly equal to those of 1981. (Bross, 8 May, 1984) This pattern is continuing through 1984 - as is seen in Table 1 .1, an extract from Irvin & Johnson financial results .

A wealth of empirical and theoretical studies has investigated the consequences of biodiversity loss on ecosystem properties. Whilst the importance of biodiversity in mediating ecosystem properties has been established, the magnitude and direction of effects vary between studies and are dependent on the biotic and abiotic conditions of the experimental system. Consequently there are still significant gaps in our understanding of how species loss may affect ecosystem properties, what the underlying mechanisms are, and how the effects of species loss are modified by environmental context.

Previous pulse-chase experiments have revealed a wide diversity of benthic response patterns to organic matter (OM) input depending on environmental setting, benthic community structure and experimental conditions i.e. quantity and quality of the added OM.  However, the mechanisms and interaction of environmental and biological factors that produce an observed response pattern are poorly understood. The present thesis set out to improve our current understanding on the set of parameters that determine benthic response patterns.  The core of this study was based on two pulse-chase experiments in two bathyal settings: the Faroe-Shetland Channel (FSC) and the SW Cretan slope in the E. Mediterranean (E. Med).  The sub-zero temperatures in the FSC enabled the observation of the benthic response in “slow-motion” and showed that the response is not static but instead might go through various “phases”.  In the warm E. Med, C processing rates were considerably lower compared to previous measurements in adjacent regions.  The discrepancy was attributed to the particularly refractory sedimentary OM at the sampling station with apparent consequences for the physiological state of the bacterial community.  Both experiments showed that bacterial metabolism and its regulation is a key factor determining the reaction of the benthic community to OM inputs.  This thesis provided further understanding on the short-term fate of organic C in deep-sea sediments but also raised certain issues that could be addressed in future studies.

In this thesis anchoring systems for marine renewable energy devices are examined for an area of interest off the coast of Southeast Florida that contains both ocean current and thermal resources for future energy extraction. Bottom types observed during previous regional benthic surveys are compiled and anchor performance of each potential anchor type for the observed bottom types is compared. A baseline range of environmental conditions is created by combining local current measurements and offshore industry standards. Numerical simulations of single point moored marine hydrokinetic devices are created and used to extract anchor loading for two potential deployment locations, multiple mooring scopes, and turbine rotor diameters up to 50 m. This anchor loading data is used for preliminary anchor sizing of deadweight and driven plate anchors on both cohesionless and cohesive soils. Finally, the capabilities of drag embedment and pile anchors relevant to marine renewable energy devices are discussed. / by Michael Grant Seibert. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Simulations have been carried out to validate a hydrokinetic energy system non-dimensional scaling procedure. The requirements for a testing facility intended to test such devices will be determined from the results of the simulations. There are 6 simulations containing 3 prototype systems and 2 possible model facility depths to give a range of results. The first 4 tests are conducted using a varying current profile, while the last 2 tests use a constant current profile of 1.6 m/s. The 3 prototype systems include a: 6 m spherical buoy, a 12 m spherical buoy and a turbine component system. The mooring line used for the simulations is a 6x19 Wire Rope Wire Core of diameter 100 mm and length 1000 m. The simulations are implemented using Orcaflex to obtain the dynamic behavior of the prototype and scaled system. / by William Valentine. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

xx, 198 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / "Bathymodiolus" childressi is a mixotrophic mussel from Gulf of Mexico cold seeps. There is no genetic differentiation of mussels among the seeps, suggesting wide dispersal of their larvae. This dissertation describes larval biology, ecology, and recruitment dynamics for "B." childressi. Cleavage is spiral at a rate of one per 3-9 hours, with blastula larvae hatching by 40 hours at 7-8 à à °C. At 12-14 à à °C, D-shell veligers developed by day 8 without being fed. Egg size and shell morphology indicate planktotrophy, but feeding was not observed. Embryos developed normally from 7-15 à à °C and 35-45 ppt. Although survival of larvae declined with temperature, some survived at 25 à à °C. Larval survivorship was similar at 35 and 45 ppt. Oxygen consumption increased from blastulae to trochophores and was higher for "B." childressi than for shallow-water mussel trochophores. Estimated energy content of "B." childressi eggs was greater than the energy content of shallow-water mussel eggs. An energetic model predicts that the eggs provide sufficient energy for "B." childressi trochophores to migrate into the euphotic zone. In fact, "B." childressi veligers were found in plankton tows of surface waters. The influence of recruitment on fine-scale distributions of adults at the Brine Pool cold seep was examined through manipulative field experiments. The "Bathymodiolus" childressi population at this site has a distinct bimodal size structure that shifts across an environmental gradient. New recruits of "B." childressi are abundant in the inner zone, where methane and oxygen are high and sulfide is low, leading to the inference that larvae settle preferentially there. Experiments were placed in the inner and outer zones and 2-m away from the bed. The number of larvae collected in traps did not differ among the three zones, nor did settlement density. Juveniles survived and grew in all zones, but more caged than uncaged juveniles survived. Mortality of uncaged juveniles was similar in all zones, suggesting that predation does not cause the bimodal distribution. These results suggest that the bi-modal distribution cannot be attributed to settlement preferences or juvenile mortality, but instead to migration or early post-settlement mortality. This dissertation includes my co-authored materials. / Adviser: Craig M. Young