Nymphon (Pycnogonida) in the Eastern Arctic

A thesis submitted to the Council for National Academic Awards in partial fulfilment of the requirements for the degree of Doctor of Philosophy.Nymphon is the largest genus of Pycnogonida reaching its greatest diversity in the Polar regions. A revision of the genus within the Eastern Arctic has proved necessary due to the numerous nomenclatural complexities which have accumulated in the literature since its last major revision by Sars in 1891. This has been achieved using multivariate analyses involving the measurement of over 1500 specimens. Fifteen species are now recognized from the area and each has been redrawn and redescribed. It has not proved necessary to propose any new species. Two distinct sub-groups are found within the genus in this area, differing in leg morphology and reproductive strategy. The first group, exemplified by Nymphon stromi, has a leg morphology suited to walking or striding. A large number of lightly yolked eggs are typically produced and the larvae spend only a short period of their development on the male ovigers before they disperse. The other group, exemplified by Nymphon hirtipes, has a leg morphology more suited to clinging. Fewer eggs are produced but these are richer in yolk and the male overwinters with the larvae which are lost only when metamorphosis is nearly complete. These interspecific differences have been discussed and it is thought that they may enable direct competition to be avoided by the exploitation of different facets of the same environment. In addition, differences in the musculature have been discussed for species within Nymphon and for the Pycnogonida generally. The male ovigers of all species examined show various adaptations which increase the surface area compared with that of the female. These modifications have been discussed and are shown to afford a greater area for attachrnent of the maturing egg masses. A histological examination of the internal structure of the femoral cement glands of Nymphon hirtipes has revealed that the adult males have a broad band of glandular tissue lying under the epidermis whereas specimens in the final larval stage have little or none. The life-cycle of Nymphon hirtipes is postulated, showing the species to take between two and a half and three years to attain maturity. It breeds only once, during its final summer. This is compared with existing knowledge of the life cycles of shallow and tropical water species

The viability of some helminth parasites in sewage sludges applied to agricultural land

A thesis submitted to the Council for National Academic Awards in partial fulfilment of the requirements for the degree of Doctor of PhilosophyThe public health and veterinary significance of sewage transmissible helminth infections is largely underestimated. Since land application is the ultimate destination of mu.ch of the sludge produced, this study was designed to investigate the longevity of helminth parasites in such material. The initial aim of the investigation was to develop reliable and quantitative isolation techniques. After determining specific gravity values for the ova of Taenia and Ascaris, several methods of isolating these were compared and modified to improve the efficiency of recovery. The effectiveness of sewage treatment for the removal of these ova was examined by measuring sedimentation rates. These values indicated that the retention times currently used in treatment plants must often be inadequate • .Anaerobic mesophilic digestion had no observable effect on the removal of ova. A number of criteria for judging the viability of ova were used to investigate the persistance of helminth ova stored in raw, digested and dried-cake sludge. Treated sludges were found to provide the leas:t favourable conditions for egg survival. The influence of ultraioletv light, temperature and humidity on egg survival was studied. Of these, humidity had the most detrimental effect. In situ lysimeter experiments were conducted to examine both persistance and viability of helminth ova under field conditions. Under the cirumstances tested Ascaris ova were found to persist longer than Taenia ova. Calves were infected. experimentally with ova recovered from raw sludge in order to obtain conclusive proof that such eggs were infective; ova retained infectivity upto 3 months. This work contributes to the understanding of the fate of animal parasites in sludges a:p:plied to agricultural land and may therefore be used to assist in the drafting of responsible policies for the safe use of sludge in agriculture

The biological and chemical effects of digested sludge as a nitrogenous fertiliser on grass crops using in situ lysimeters

A thesis submitted to the Council for National Academic Awards for the degree of Doctor of Philosophy.This thesis details field and laboratory experiments on the biological and chemical effects of liquid anaerobically digested sewage sludge (LDS) used as a nitrogenous fertiliser on grass crops. The main objectives of the investigation were to ascertain the nitrogen (N) fertiliser value of LDS on grassland and evaluate its leaching losses using monolith lysimeters. Some LDS volatilisation studies were undertaken in the laboratory and a N balance compiled for the field lysimeters. To enable a detailed assessmBnt of crop uptake of LDS N some LDS was prepared with isotopic N15 using laboratory anaerobic digesters. The product LDS contained N15 as organic and inorganic N and was similar to a typical LDS. The field lysimeters were arranged as an integral part of each field plot and some techniques devised for their installation in situ. For laboratory work a scaled-down version of the field lysimeter was used. An assessment of the comparability of lysimeter and field conditions showed a satisfactory correlation with respect to crop productivity. Similar levels of N15 uptake were recorded for the field and lysimeter swards. Crop productivity trials showed that LDS applied as a single and split application was about 70% as effective as a split dressing of ammonium nitrate (Nitram). Evidence from the field trials suggested that LDS organic N contributes less than 10% of its fertiliser value during its year of application. Leaching losses of LDS were found to be similar to those of Nitram. At application rates equivalent to 300 kgN/ha/season typical nitrate-N concentrations in the leachate water were 1 mg/1 and 0.1-6.2% applied N was lost from the field A quick crop response to LDS N was recorded with N15 accumulation by the crop 7 days after LDS application. Crop productivity trials indicated a lack of sustained response by the grass to LDS applications

The volcanic geology of the southern wall of the Valle Del Bove, Mount Etna, Sicily

A thesis submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy of the C.N.A.A.The Valle del Bove is a horse-shoe shaped depression, 8km long and 5km wide, cut into the eastern flanks of Mount Etna, Sicily. In the southern cliff walls there are exposed the lavas and pyroclastics erupted by six ancient centres of activity which existed in the vicinity of the site now occupied by the Valle del Bove. The majority of these volcanics originated at a centre, Trifoglietto II, which occupied a position on the site of the southern Valle del Bove, and which was still erupting lavas at 25,000 ys BP. A reconstruction of the topography which previously existed within the Valle del Bove, is accomplished by extrapolating preserved contours on the northern and southern walls of the depression. Reconstruction of the Trifoglietto II centre shows that its summit was probably between 2500m and 2600m above present sea-level, and that it consisted of a cone constructed predominantly from pyroclastic materials, overlain on its southern and eastern flanks by lavas. A stratigraphy is constructed for the southern wall. The Trifoglietto II lavas rest unconformably upon the eroded remnants of an older centre, and are themselves overlain by the products of younger centres. All the lavas exposed in the southern wall are of alkalic affinity, and comprise a trachybasaltic suite ranging from hawaiite to benmoreite. Variation in the chemistry of most of the lavas can be explained by their differentiation at high levels in the crust, from a more basic magma of alkalibasalt/hawaiite composition. Chemical variation in the Trifoglietto II lavas, however, can best be explained as a result of generation by the partial melting of garnet-peridotite material at upper mantle depths and pressures. A study has been made of the numerous dykes exposed in the walls of the Valle del Bove., the alignments of which parallel trends which are important on Etna at the present time. It is proposed that the Valle del Bove was formed by phreatic or phreato-magmatic eruptions which destroyed the Trifoglietto II centre, some 15-17,000 ys BP, following magmatic extinction at the centre. The eruptions produced lahars which are evident to the east of the depression, and extensive air-fall ashes. Subsequent enlargement of the Valle del Bove was accomplished by fluvial erosion

Some studies in the contribution of nitrogen fixing blue-green algae to the nitrogen economy of temperate soils

A Thesis for the degree of Doctor of Philosophy submitted to the Council for National Academic Awards based on work carried out at Luton College of Higher Education, Beds.The work in this thesis is an extension of a large study carried out by this college at Rothamsted Experimental Station (J. Featherstone-Witty, Ph.D thesis, 1974; with Keay, and Froggatt in press) and was aimed at scaling down the fieldwork to lysimeter investigations in order to elucidate the true value of algal inoculation as a replacement for synthetic fertilizers. Two lysimeters (each measuring 5m. x 3m.) were constructed above ground on concrete rafts with a built in facility to collect drainage water from the four quarters of each lysimeter. Both units were filled with calcareous soil (pH. 8). Each unit was divided into 4 treatments and sown to spring wheat. Previous indications were that this variety would benefit more from algal release of nitrogen than winter wheat because of a later maturation, and hence greater likelihood of the ears receiving nitrogen released from algal cells during late summer. A continuous record was kept of variations in soil, crop and drainage water nitrogen together with surface nitrogen fixation measurements (using the acetylene reduction technique), so that estimates of the efficiency of algal inoculation, to increase soil-N levels, could be made. Laboratory studies have suggested nitrogen fixation occurs only in soils low in nitrogen (less than about 4ppmJ and algal cells apparently release very little extracellular nitrogen when grown on solid surfaces. These low levels of nitrogen would not support crop yields equivalent to those achieved by the application of synthetic fertilizers. Results from the two year lysimeter study suggest no improvement in crop yield for the algal inoculated treatments, compared with the controls, though total crop nitrogen, for the algal treatments was approximately 7% higher than the fertilizer treatments and 60% higher than the mean value for the two controls; ear nitrogen was as much as 46% higher than the controls. Algal inoculation, together with herbicide application, proved the best treatment, improving both crop dry weight and nitrogen composition significantly

Tectonic studies at the S.W end of the Aar Massif, Switzerland

Submitted to the Council for National Academic Awards for the degree of Doctor of PhilosophyComparisons are drawn of the effects of the Alpine orogeny on Mesozoic sediments and the underlying Hercynian massif basement rocks at the SW end of the Aar Massif. The study has also brought a clearer understanding of the pre-Permian geological history of the massif. The main lithological units in basement and cover are briefly described, and their mapping on 1 : 10,000 scale has shown large and medium scale structures. Deformation sequences have been established for the basement (D1b to D6b) and for the cover (D1c to D3c) and there is a clear correlation of Alpine st ructures (D1c to D3c equivalent to D4b to D6b). In the basement the late-Hercynian deformation of Upper Carboniferous metasediments is recognizable. These sediments were deposited on the older Altkristallin gneiss complex which had previously suffered the main Hercynian deformation and metamorphism. The trend of Alpine structures is subparallel to the trend of late-Hercynian structures, producing difficulties in discernment, and consolidating the regional NE-SW trend of basement structures. Alpine deformation was fairly simple, comprising one main deformation, followed by two weak phases producing only localized small-scale structures. Quantitative strain analysis for the main Alpine deformation investigates local situations and compares different types of strain marker. Incremental strains are recorded in curved pressure shadow quartz fibres in both basement and cover. These indicate early extension directions steeply plunging SE, later rotating through gentle plunge E, to subhorizontal NE and gentle plunge SW. Deformed Carboniferous pebbles, and cover ooids, intraclasts, faecal pellets, and ammonites have been analyzed, but all except faecal pellets suffer from the presence of initial preferred orientations and ductility contrasts with their matrix materials. Illite crystallinity studies show that the pelitic rocks investigated (basement and cover) reached a degree of Alpine metamorphism just inside low-grade as defined by WINKLER (1974) though the presence of graphite may have allowed this grade to be attained at relatively low temperatures. Further studies show this to have been a Barrovian-type syntectonic metamorphism. Generally similar finite Alpine deformation of basement and cover may be inferred from similar development of structures and similar quantitative strain estimates, but the very varied compositions and textures of rocks will have required somewhat different deformation mechanisms, and varied strain distribution

Aspects of the biology of polar pycnogonids

Submitted to the Council for National Academic Awards in fulfilment of the requirements for the degree of Doctor of Philosophy.The internal morphology of fixed specimens of Antarctic pycnogonids WDS examined. Theories postulated during the course of these histological studies were then tested and modified by observations on live material and specimens fixed specially for histochemistry on visits both to the Arctic and d Antarctic. Live material was also transported back to Britain from these regions and cultured in refrigerated marine aquaria. The digestive system was studied in considerable detail. It is suggested that digestion is intracellular with gut cells changing their morphology during their lifetime. Embryo cells develop into Absorptive cells which at some stage take up a glandular appearance but not a glandular function. There are therefore two gut cell types, 'Embryo' and 'Absorptive/glandular'; this is in disagreement with some previous authors who separate the latter. The rele of the gut cell in the light of present day lysosome theory is discussed and a re-interpretation of work by previous authors suggested. It is found that the digestive process is slow and the prey tastes of the species studied, catholic. Furthermore, it is found that some species can survive for long periods without appearing to feed. Suggestions are made as to the significance and mechanisms of these phenomena. Mass transport in the body cavities is considered flnd compared with that of Hydra, an animal with which previous authors have made comparisons; - their philosophy is questioned. Blood flow, heartbeat and intestine movements are also considered and suggestions for future studies made. The role of blood itself is studied a possible clotting system described. Preliminary experiments on blood electrophoresis and chromatography indicate that such techniques may be useful in clarifying some complexities of pycnogonid classification and might provide a means by which future workers in the field might better link nutritional state, mass transport, digestion and external environment conditions

Algal nitrogen fixation on solid surfaces and temperate agricultural soils

A thesis presented by JOHN FEATHERSTONE-WITTY for the Degree of Doctor of Philosophy in the Faculty of Science of the University of LondonThis thesis examines various factors controlling algal nitrogen fixation and nitrogen release in temperate agricultural soils. New apparatus for investigating nitrogenase activity on uniform soil grown algal crusts and for the in.situ estimation of nitrogen fixation in the field is described. The effects of oxygen concentration and temperature on acetylene reduction by soil grown cultures of Nostoc ellipsosporum in the light and in the dark suggest that ATP generated by oxidative phosphorylation contributes to fixation even in the light. The oxygen concentration giving optimum nitrogenase activity depends on the intensity of illumination, largely because of the continuing contribution from dark fixation. The oxygen dependent acetylene reduction continued throughout the night in the field at 20% of the midday rate. This proportion is dependent on daytime light intensity and day/night temperature drop. The release of nitrogenous compounds by soil and sand grown cultures of N .ellipsosporum was investigated in the laboratory. Algal cultures growing on sand released only 20/0. of the total nitrogen compared with 10% released by liquid cultures. Freezing to below -30C, drying to less than 4% moisture or pathogenic infection all cause extensive cellular lysis with a concomitant loss of nitrogenase activity, followed, after several days, by a surge in ammonia concentration. The recovery of nitrogenase activity after re-wetting was investigated in the field after a period of dry weather. All samples achieved a steady rate of nitrogenase activity after 400 minutes irrespective of the magnitude of recovery. Nitrogenase activity in the field was monitored at weekly intervals using an in situ technique over a two year period on Broadbank, one of the Rothamsted classic plots sown to winter wheat. The seasonal fixation rates varied from 1.4 to 28 Kg/ha depending on the fertilizer and herbicide treatment. The greatest seasonal fixation was given by non-herbicide plots receiving 48 Kg N/ha of applied nitrogen. The effect of various species of algal inoculum was investigated on 60 plots sown to winter wheat with and without irrigation and added nitrogen. A significant increase in fixation was produced and the most effective treatment was a liquid application of N. ellipsosporum. Both the N. punctiforme and Anabaena cylindrica were more effective when applied as dried sand cultures. The most important single factor limiting algal development in field experiments was soil moisture