We investigate in three problems some effects of heat transfer in linked ocean/atmosphere models. In all the problems the term involving vertical thermal conduction is retained in the heat transfer equation and both molecular and eddy values for the conductivity are considered. In Part 1 we look at a two layer model, ignoring all macroscopic motion; the governing equation for both layers is therefore the heat transfer equation. With suitable boundary conditions the 'phase lag' between a heat source in the upper layer and the temperature at the inteface of the layers (the sea surface) is studied. In Part 2 we consider a one layer model. A perturbation model due to Blinova is extended to include the heat transfer equation. One boundary condition introduces a time dependent heat source at the bottom of the layer, simulating a heating at the sea surface. The stream function is obtained at the bottom of the layer. Finally, in Part 3, the stability of a two layer liquid model is examined. Macroscopic motion in the lower layer is ignored. The perturbation equations for the two layers are solved and homogeneous boundary equations yield an equation of consistency for the system which leads to criteria for stability. These criteria are found using difference methods and, following Meksyn we produce first order correction terms to Eady's well known stability results. Using Meksyn's methods once more, the model is extended to include a variable coriolis parameter and a stability equation is found.

A brief review is made of Laplace's equations governing tidal oscillations and of the subsequent claims and counter-claims on their validity. The purpose of this study is to investigate these claims further, with regard to long period and semi-diurnal oscillations. As the underlying assumptions are of importance, these are considered first in some depth. A set of equations is thereby formulated which differ from Laplace's equations in that extra terms of the Coriolis force are retained. These equations are taken as the basis from which a comparison is made with the previous findings. Taking the semi-diurnal constituent first, a solution is derived in the Equatorial Canal. Graphs are produced showing the velocity components as functions of canal depth and width. These compare favourably with Laplace's theory. However, whilst the description of the tidal elevation is qualitatively the same as before, there are significant quantitative differences. In particular tides become direct only in a much deeper ocean than previously predicted. Using a similar approach a solution is derived for the long period constituent in a canal-like region near the North Pole. Whereas Laplace's theory for this region gives a solution involving Bessel functions, these become Modified Bessel functions in the derived solution. Arising from this, some different effects are noted in the velocity components.

Atmospheric CO enrichment is a key factor contributing to global climate 2 change. Major consequences of climate change include increasing sea surface temperature and decreasing seawater pH (ocean acidification) – both of which are predicted to lead to an increase in ocean hypoxic events. Early ontogenetic stages of invertebrates have shown sensitivity to these environmental changes. Previous research has focused on short-term exposure to these environmental factors; however, the long- term and multi-generational effects of ocean acidification on organismal reproduction and development have received little attention. The aim of this thesis is to address this shortcoming for reproduction and early embryonic development of the economically- and ecologically-important sea urchin, Paracentrotus lividus (Lamark, 1816) and the reef-forming invasive polychaete, Ficopomatus enigmaticus (Fauvel, 1923). Fertilisation success and early embryogenesis of P. lividus were negatively impacted under conditions of increased pCO, at ambient temperature and ambient 2 +2°C after 12 months exposure. Sperm motility – determined by computer assisted sperm analysis (CASA) – showed a significant increase in average swimming speed measured as curvilinear velocity (VCL) at increased pCO levels after 6 months but by 2 12 months VCL values had decreased. There was no overall significant effect of pCO 2 on VCL but there was a significant reduction in fertilisation success under hypoxic conditions. Increasing pCO levels appeared to buffer the effects of hypoxia, however, 2 with significantly lower fertilisation success observed only under hypoxic conditions at ambient pCO. Multi-generational experiments examined the effects of increased pCO on 2 F.enigmaticus. Both percentage sperm motility and sperm VCL were similar between experimental treatments, but there was a significant difference between generations 0 and 2. In contrast, fertilisation success was negatively affected by both pH and generation, with a significant reduction seen with pH at all generations and a significant reduction seen between generation 0 and generation 2. Oocyte diameter was also significantly affected by pH and generation, with a significant increase in egg diameter seen at generation 1 in all pH treatments except pH 7.95, which shows a significant increase and generation 2, which suggests differing levels of maternal investment. This research suggests that in the long term, ocean acidification, temperature and hypoxia may seriously impact the reproduction and development of two important marine invertebrate species. This research highlights the need for further long-term investigation involving multiple stressors to provide a more comprehensive understanding of the long-term effects arising from changing oceanic chemistry.

No description available.

The Dove Time Series is a plankton monitoring station in the Northumberland coastal sea which has been sampled since 1969. Over the 20th century, major changes have occurred in the North Sea plankton which have in part correlated with oscillation in atmospheric mass over the Northern Hemisphere, the North Atlantic Oscillation (NAO). Westerly winds when the NAO is positive phase block northern low pressure systems and transport warm Atlantic water into the North Sea extending stratification, leading to greater phytoplankton biomass. Phytoplankton biomass in the central North Sea reached a sustained higher level after 1985. Phytoplankton, zooplankton and ichthyoplankton datasets were created or extended from the Dove Time Series to study the effect of oceanographic change at this location. There was a change to a high abundance community 10 years later, in 1995. The most important predictor of phytoplankton abundance was not the NAO index, but the Atlantic Meridional Oscillation (AMO), which exhibits 60-100 year and subordinate 11 and 14 year periodicity, describing a deviation from the long term sea surface temperature (SST) mean in the North Atlantic. Phytoplankton periodicity partly matched the 14 year period in the AMO, which correlates with a feedback mechanism of westerly versus northerly wind in the North Atlantic, regulating ocean-atmosphere heat flux. Zooplankton abundance was predicted by SST and ratio of maximum to minimum abundance by phytoplankton/AMO. Oceanographic conditions that were contemporary with the state of the AMO anomaly after 1995 promoted higher spring phytoplankton abundance and neritic copepod abundance peaks. Ichthyoplankton variability was not synchronous with these lower order changes, probably as a result of different effects on adult fish. The cyclical nature of the AMO means both low and high biomass communities observed in the Dove Time Series are part of one regime.

No description available.

Phosphonates, comprise a group of organic phosphorus molecules, characterised by a direct C-P bond, rather then the more usual C-O-P bond. Although phosphonates are resistant to both chemical and thermal hydrolysis, there are several bacterial enzymes capable of breaking the C-P bond, and thus liberating inorganic phosphorus. Despite indications that phosphonates comprise 30% of the dissolved organic phosphorus pool in the ocean, little is known of their fate, and research has concentrated on their degradation in oligotrophic environments. However, the quantification and speciation of phosphonate molecules in oceanic environments remained elusive, and although some advances in analytical methodology were made during this thesis, no significant progress was made on the central problem of the extraction of a highly polar analyte with an affinity for divalent cations, from a highly polar, ionic medium. During this thesis, the widespread presence of phosphate-limitation independent phosphonate hydrolase in genomes of marine bacteria, as well as in metagenomic libraries is illustrated, and the presence and expression of some of these genes is illustrated in such diverse marine environments, as coastal ocean, upwellings, coral-associated bacteria and shellfish pathogens. The expression of alkaline phosphatase (AP) was observed in high nutrient upwelling environments and this was linked with the expression of phosphoacetaldehyde dehydrogenase, a phosphonate-degrading enzyme also thought to be under pho regulon control. A possible mechanism involving carbon source activation of the pho regulon under euthrophic conditions is illustrated in the shellfish pathogen, Vibrio Tubiashii, which questions the assumption that DOP utilisation is only important during oligotrophic conditions.

A method is developed here for the assimilation of surface restricted satellite data into three dimensional numerical ocean models. Satellite altimetry provides observations of the dynamic topography i.e. the time variations in sea surface height, which provides some constraints on the three dimensional ocean state, but no unique solution. Traditionally, the surface data is projected into the deeper ocean by statistical methods. Here, the pre-analysis model potential vorticity fields are conserved at each analysis, which provides a unique solution for the vertical structure of each model gridpoint when combined with the local sea surface height. The assimilation method is tested in a series of twin experiments, in which the real ocean is substituted by a numerical model run, and limited datasets from this control run are assimilated into another model run with different initial conditions in an attempt to reconstruct the full three-dimensional state of the control run from the surface information alone. The assimilation run fields are then compared with the full control fields in order to determine the success of the assimilation method. Twin experiments with a four layer quasigeostrophic model, and a 21 level primitive equation model show that the typical amount of information available from a single altimeter is sufficient to constrain the full three-dimensional circulation of the ocean model, within the twin experiment framework. The reliance upon dynamically-based conservation laws rather than pre-calculated statistics makes the method computationally cheap and easily portable between models.

In this thesis a novel method for assimilating upper ocean temperature profiles with salinity adjustments into numerical ocean models is presented. The approach uses a <i>T-S</i> relation more local in space and time than the climatological <i>T-S</i> used in previous studies. The assimilation method also avoids convective instability as the temperature data are introduced. In order to test the method, three sets of experiments are carried out. First, Conductivity-Temperature-Depth measurements in the western tropical Pacific, and also instantaneous fields from an ocean model, are used to test the assimilation method by combining one profile with another. These tests recover the salinity profiles and the 0-500-m dynamic height very well (differences smaller than 1 dyn cm). By contrast, analyses using a climatological <i>T-S</i> relation did not provide a good salinity profile or dynamic height (greater than 3 dyn cm errors). Second, a synthetic assimilation experiment using a 3-D primitive equation model is carried out. Four runs are considered: the truth (<i>Tr</i>), the parallel (<i>Pa</i>) and two assimilation runs, one in which the salinity method is applied (<i>A_ST</i>) and the other in which salinity is left unmodified during the temperature assimilation (<i>A_SZ</i>). The only difference between <i>Pa </i>and <i>Tr</i>is that <i>Pa</i> is forced by a wind stress 15% larger than <i>Tr,</i> so as to simulate a systematic observational error. <i>A_ST</i>and <i>A_SZ</i> use the same forcings as <i>Pa. </i>Vertical temperature profiles down to a depth of 525 m are taken as synthetic data from <i>Tr</i>and assimilated every 30 days for two years into <i>A_ST</i>and <i>A_SZ</i>. Results show that <i>A_ST</i>yields better salinity analyses than both <i>Pa</i> and <i>A_SZ</i>, which, in terms of rms errors, translate into at least 15% improvement at the end of the 2-year experiment. In addition to assessing the success of the assimilation method (e.g. using <i>T</i> and <i>S</i> rms), a more physical analysis of the model modifications, due to the assimilation, is presented.

Biostratigraphic analysis of the lower part (Oxfordian-Kimmeridgian) of the Upper Jurassic Humber Group in the Outer Moray Firth of the North Sea and coeval onshore Scottish sections has resolved a long-standing controversy regarding the stratigraphic range of key dinoflagellate cyst (‘dinocyst’) taxa. The biostratigraphic ranges of these key species can now be shown to be comparable for Scotland, the North Sea and the classic Upper Jurassic English sections, indicating that the former North Sea Dome did not represent a barrier to faunal migration in Kimmeridgian times. Causes behind previously reported biostratigraphic anomalies can now be demonstrated to result from a combination of erroneous identification of cored material, inconsistent taxonomy and past failures to adhere to the codes of taxonomic nomenclature. The resolution of these reported biostratigraphic anomalies enables a new, robust, chronostratigraphically calibrated dinocyst biozonation to be proposed for the Regulare to Mutabilus Standard Ammonite Zones of Scotland and the North Sea. The application of the unified biostratigraphic scheme enables a revision of the lithostratigraphy, and therefore depositional history, of the Piper and Kimmeridge Clay Formations of the Humber Group in the Outer Moray Firth. The results from the Ivanhoe, Rob Roy and Hamish fields of United Kingdom Continental Shelf (U.K.C.S.) block 15/21 indicate that the Mid Shale Member, a component part of the Piper Formation, was deposited from Oxfordian, Rosenkrantzi Zone times to basal Kimmeridgian, Baylei Zone times. This conclusively demonstrates its strategraphic equivalence to the I-shale Member of the Piper field for the first time, thus necessitating redefinition but simplification of the lithostratigraphic terms used in the basin. Deposition of the Supra Piper Sands was terminated by a transgressive event which was initiated in Mutabilis Zone times, with Kimmeridge Clay Formation mudstone deposition occurring in response to a major transgression which reached its maximum extent in the Eudoxus Zone.