Inaug.-Diss.--Zurich. / From Archiv für Hydrobiologie. Bd. III. "Durchgesehene Litteratur": p. 175-177.

Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2006. / Includes bibliographical references (leaves 155-173).

Thesis (M.S.)--University of North Carolina at Greensboro, 2006. / Title from PDF title page screen. Advisor: Parke A. Rublee.; submitted to the Dept. of Biology. Includes bibliographical references (p. 35-40)

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references. Also available in electronic version.

Thesis (Ph. D.)--Massachusetts Institute of Technology and woods Hole Oceanographic Institution, 1984. / Includes bibliographical references.

Bacterial abundances and production, and the size distribution of oxygen metabolism and chlorophyll a concentration were followed through two seasonal cycles in the Menai Strait (North Wales, U. K. ) and during austral summer in the Southern Ocean. In the Menai Strait, spring blooms were characterised by a diatom to Phaeocystis succession. In both the Menai Strait and the Southern Ocean, meso- and microphytoplankton dominated phytoplankton production and biomass during diatom blooms. Nanophytoplankton predominated when production and biomass were low, i. e. during the summer in the Menai Strait, in waters near the Polar Front, and in some samples from the Weddell Sea. In both ecosystems substantial respiration resided in the bacterial (< 0.8 gm) size-fraction. Consequently during the Menai Strait temporal study, phasing of respiration in relation to photosynthesis was strongly influenced by bacterial metabolism and abundance changes. The respiration maximum occurred 1-2 weeks after the Phaeocystis abundance maximum. An explanation for this temporal lag was sought by considering the time scales of flow of organic material between the phytoplankton and the bacteria. The observations were consistent with routes via a slowly cycling pool, such as polymeric organic material. This pool would function as a reservoir and result in microheterotrophic respiration persisting after the decline of photosynthesis, causing a positive to negative temporal sequence in net community production. There was no evidence for differences in any measure of microbial biomass between the Southern Ocean and the Menai Strait. General relationships could be derived for both ecosystems: (a) the biomass quotient (< 20 µm phytoplankton / unfractionated phytoplankton) generally increased sharply as unfractionated phytoplankton biomass decreased, (b) bacterial biomass generally increased as phytoplankton biomass increased, (c) the biomass quotient of bacteria to unfractionated phytoplankton increased sharply as unfractionated phytoplankton biomass decreased. Different relationships were derived for the oxygen fluxes in terms of phytoplankton biomass for the Southern Ocean and Menai Strait observations. In these relationships, the oxygen fluxes were generally relatively (relative to the explanatory variable: phytoplankton biomass) higher in the Menai Strait. In contrast, a single relationship for DCR in terms of GCP was fitted for both data sets. This difference is consistent with a temperature effect on the oxygen fluxes, with GCP and DCR similarly suppressed at lower temperatures.

Purely qualitative investigations of the plankton of an area cannot provide sufficient information for the full understanding of the seasonal changes that oocur nor of the interrelation of the various planktonic plants and animals. Quantitative data must be obtained before these can be properly described. Except for the qualitative records by Scott (1906, 19(7) and Hiddell (1914) the plankton of waters off the north ooast of Wales, and of the Menai Straits in particular, has tended to be neglected. The unusual hydrographic conditions of the Menai Straits, which connect areas whose fauna and flora show considerable differences (Crisp &amp; Knight-Jones, 1953) suggested such studies would be rewarding. In describing the various populations the policy in the present work has been to give the details of the most numerous species of both plants and animals individually and to summarize the others in various groups. This simplified the description and discussion of the dynamics of the population, which would be difficult to follow if all species were described in detail. At an early stage in the investigations it became obvious that the plankton of these coastal waters differed considerably from that of the Irish Sea in general, which has been described by Williamson (1956). In particular tho copepods Oithonina nana (Giesbrecht) and Euterpina acutifrons (Dana) were prominent species in the Menai Straits. Euterpina acutifrons was found to have several points of interest. Firstly, dimorphism occurs in the male; this has received considerable attention and has been found to be of some significonce in the biology of the species. Secondly, Euterpina is pelagic, while most other harpacticoid copepods are benthic or littoral. Investigations of its development (which was inadequately described by Tesch (1915)) in culture allowed a consideration of the adaptive modifications of Euterpina to a pelagic existence, of its rate of growth and development, and of the developmental aspects of dimorphism in the male. The latter has been a controversial subject in previous studies of copepod development (Sewell, 1912, 1929, 1940; Gurney, 1929; Coker, 1934) . Thirdly, Euterpina has a world-wide distribution, mainly centered in the warmer seas. Consideration of this led to investigations of some aspects of the relationship between the environment and the development of the species and also to a comparison of its breeding season in the waters round Anglesey with those reported in other latitudes . The present work also includes studies of the larval development of Oithonina nana, another warm water form. Despite its being a very common plankton animal, the larval. development of this species has tended to be neglected. In the work as now presented the studies of these species are given a considerable proportion of the total space, since the data provided on their development, growth and breeding illuminate the general study of the plankton which, in turn, forms a background to the detailed studies. The form of presentation of this thesis may perhaps call for some explanation. The sections into which it is divided have been prepared in the form of separate papers intended for publication. This means that figures and tables are numbered oonsecutively within each section and not continuously throughout the thesis, and also that a separate bibliography will be found at the end of each section. It is hoped that this method of presentation will cause no inconvenience to the reader.

A microprocessor- controlled coulometric system for measuring total inorganic carbon in seawater samples was refined. A precision of 0.5 micromoles/kg (one standard error) from a single sample was routinely achieved in the laboratory. This was reduced to 1.0 micromoles/kg at sea due to an increase in the instrument blank. The system has proved to be a robust and reliable method, well suited for routine plankton productivity measurements and oceanic mapping. The coulometric technique was used in conjunction with an automated Winkler oxygen method to make in vitro and in situ observations of planktonic photosynthetic ana respiratory quotients. In common wi th earlier published observations, a wide range of quotients were obtained. A detailed consideration of analytical and sampling errors led to the conclusion that the quotients could mostly be explained by the stoichiometry of conventional biochemical products and reactants. In situ observations were carried out within mesoCosms:-Tn one field study, particular attention was paid to the correction of data for physical mixing within the mesocosm and exchange with the atmosphere. A dye diffusion study coupled wi th continuous temperature profiles led to the the conclusion tha t the circulation wi thin these bags is complex and cannot be described by use of a one-dimensional vertical diffusion model. The total inorganic carbon measurements determined from vertical CTD profiles during the 1987 RV Challenger cruise were compared to similar stations sampled during the Transient Tracers in the Ocean Programme (1981). Although the TTO measurements were calculated from a potentiometric titra tion there was no evidence for major errors of accuracy.

Climate change has a profound impact on the phenology and abundance of plankton in the NE Atlantic and North Sea. There is concern that harmful algal bloom (HAB) species may increase, accompanied by negative socio-economic impacts, including threats to human health and marine harvesting. We reviewed historical major UK outbreaks of poisoning and attempted to examine the epidemiology on a finer scale by linkage of hospital admissions, GP and pathology records. As expected the incidence of shellfish poisonings was very low but accurate identification of poisoning was generally unreliable. The current UK shellfish monitoring programme is the key indicator for monitoring trends in the risk of human exposure. Using the Continuous Plankton Recorder (CPR) survey, we mapped spatial and temporal trends of various phytoplankton, including HAB species, and zooplankton (Tintinnids and Calanus). We found fundamental shifts in the relative abundance of diatoms versus dinoflagellates, with a dramatic dinoflagellate decline in recent years. Northward shifts in abundance were found for some Tintinnid and Calanus taxa. Using criteria of statistical causality, these changes were linked to climate, in particular sea surface temperature and increasingly windy conditions in the summer, with a notable non-linear interaction between these factors. Focusing on Calanus, we showed the strength of statistical links between abundance and climate variables can wax and wane as the time series lengthens. We found tentative evidence for adaptation of Calanus to climate change, but not at a level that could reverse overall long-term patterns. Links with climate are often argued to be proxies for unobserved mechanisms that determine species abundance, such as stratification. We developed a new stratification index, covering the whole NE Atlantic from 1970 to 2009. We propose that this has wide applicability in marine climate change studies. Throughout, our work demonstrates the importance of consistent long-term ecological survey data.

Caccolithopliorids are important members of phytoplankton communities in most parts of the world's oceans. The formation, release and flux of the calcite scales (coccoliths) of these organisms over millions of years, has led to sedimentary deposits of great geological significance. The reporting of immense blooms of coccolithophorids by satellite photography and their passible involvement in atmospheric sulphur emissions has emphasised the necessity for further information on their distribution and ecology. During an extensive sampling programme in the N.E. Atlantic, water samples were collected throughout the photic zone at 30 stations. Scanning electron microscopy of filtered water samples enabled coccolithophorid family and species distributions to be compiled. It was found that certain species assemblages could be assigned to distinct biogeographic zones and that these zones closely conformed to the movements of the N. Atlantic surface currents. However, at the Azores Front it was shown that a transitional region existed between the cold and warm water masses, where the flora of each zone could be found. Detailed studies of coccolithophorid vertical distribution has shown that most species can be assigned to discrete depth bands within the euphotic zone. Furthermore, it was noticed that in two species which have no depth preference, the degree of calcification increased with depth. One of these species, E. huxleyi, displayed two ecomorphotypic variants differing in their calcification, size and morphology. During two east to west transects it was noticed that the halocaccolitiiophorid numbers increased towards the Mid-Atlantic Ridge. A number of new species are described and current taxonomic problems reviewed.