Thesis (Ph.D.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 116-135.

Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Oceanography." Includes bibliographical references (p. 35-39).

Thesis (Ph. D.)--University of Chicago, Dept. of the Geophysical Sciences, June 2003. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Includes bibliographical references.

Thesis (Ph. D.)--Florida State University, 2006. / Advisors: Don R. Levitan and Thomas E. Miller, Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed Sept. 22, 2006). Document formatted into pages; contains xi, 110 pages. Includes bibliographical references.

Η Μεσόγειος αντιπροσωπεύει µια από τις περιοχές “κλειδί” στις παλαιοωκεανογραφικές µελέτες από τη στιγµή που οι υδρογραφικές και ιζηµατογενείς διαδικασίες είναι ευαίσθητες στις κλιµατολογικές αλλαγές των παρακείµενων ηπείρων. Οι περισσότερες δηµοσιευµένες µελέτες εξέταζαν τις διαδικασίες που είναι υπεύθυνες για την απόθεση σαπροπηλών στην Ανατολική Μεσόγειο κατά τη διάρκεια του Πλειστοκαίνου. Η µελέτη αυτή βασίζεται στην µικροπαλαιοντολογική ανάλυση βενθονικών τρηµατοφόρων του πυρήνα ΤΙ13, ο οποίος συλλέχθηκε από το Ανατολικό Κρητικό Πέλαγος και υπάγεται στο βάθος απόθεσης του σαπριπηλού S1. / -

The subtidal whelk Burnupena papyracea (Brugière) co-occurs with a voracious predator, the rock lobster Jasus lalandii (Milne Edwards), in situations where other potential prey are largely eliminated. This has been ascribed to a symbiotic bryozoan, Alcyonidium nodosum (O’Donoghue and de Watteville), which characteristically encrusts the shells of B. papyracea and deters feeding by Jasus. In this study it is shown that this is not due to physical effects of either induced physical defences in the bryozoan or increased shell strength due to the presence of the bryozoan. Neither spectroscopic screening of chemical extracts of the bryozoan nor analysis for volatile constituents revealed any apparent chemical components that are likely to deter feeding. Chemical extracts also failed to show larvicidal effects in a standard toxicity assay using the brine shrimp Artemia salina (Leach). Despite this, bioassays using individual Jasus indicated a chemical basis for feeding deterrence. The assays were run separately on three sets of Jasus and some repeats of assays gave contradictory results. However, assays showing no significant effect of treatment occurred with moulting Jasus, involved very low overall feeding rates and so gave a less convincing result. In other assays Jasus always avoided Burnupena papyracea with live Alcyonidium encrusting the shell, and food pellets containing Alcyonidium or an Alcyonidium extract. Significant preferences were shown for an unencrusted whelk, B. cincta (Röding), over B. papyracea; for B. papyracea with the bryozoan scraped off over natural B. papyracea; for B. papyracea on which the bryozoans had been killed with liquid nitrogen over untreated B. papyracea; and for food pellets prepared from ground, dried mussel over pellets prepared with dried mussel mixed with A. nodosum or its crude organic extract. It is concluded that the protection which Alcyonidium confers on Burnupena papyracea does have a chemical basis, but that the chemical responsible is either present in only trace quantities, or that it is a structurally unremarkable compound which is distasteful to Jasus. This work highlights both the advantages of using ecologically relevant bioassays (positive results when standard techniques give a negative result) and also the disadvantages (logistic constraints on sample sizes when using large test animals and individual variability in a relatively sophisticated test animal).

Climate warming during the latest Permian is associated with the most severe mass extinction event of the Phanerozoic, and the expansion of hypoxic and anoxic conditions into shallow shelf settings. Our understanding of the magnitude, pattern and duration of the extinction event and subsequent recovery remains equivocal. Evidence suggests that the action of waves provided an oxygenated refuge, i.e. ‘habitable zone’, above wave base that may be limited to high latitudes, in association with a faster pace of recovery. In addition, advanced recovery faunas have been documented from the Induan and there is evidence from the pelagic realm that further biotic crises may have delayed the recovery of benthic organisms coinciding with large carbon isotope perturbations at the Lower Triassic sub-stage boundaries. To test these hypotheses, novel palaeoecological data was collected from localities in Hungary, northern Italy, and Svalbard. To understand better the ecological impact of the extinction, a database of all known benthic marine invertebrates from the Permian and Triassic periods was created, with each taxon assigned to a functional group based on their inferred lifestyle. This study found that the skeletal and ichnofaunal assemblages consistent with advanced ecological recovery are limited to settings aerated by wave activity, which supports the habitable zone hypothesis. In the western Palaeotethyan sections it was found that the proximal end of the ‘habitable zone’ was limited by persistent environmental stress attributed to increased runoff that resulted in large salinity fluctuations, increased sedimentation rates and eutrophication creating an environment only favourable for opportunistic taxa. In the Tirolites carniolicus Zone, however, the ‘habitable zone’ expands into more proximal and offshore settings. This is associated with climate cooling in the late Spathian. The data also demonstrate that despite the taxonomic severity of the extinction, only one mode of life went extinct and only one subsequently evolved in the aftermath. Functional diversity was, however, reduced in particular regions and environmental settings, and recovery varied spatially and temporally. In western Palaeotethys, benthic communities record evidence for biotic crises, such as reduced tiering in the Smithian, associated with Early Triassic carbon isotope excursions, but, until the Spathian there was no significant change in the composition of the benthic faunas.

Abstract In this thesis, I used the Chironomid Pupal Exuvial Technique (CPET) to detect anthropogenic impacts and to determine chironomid species composition in boreal rivers and lakes. The main objectives of the thesis research were i) to evaluate the importance of timing of sampling in the use of the CPET method (I, II), ii) to identify chironomid indicators of different environmental conditions (II, III, IV), and iii) to compare performance of the CPET method and more traditional sampling techniques in detecting anthropogenic impacts and chironomid species composition (III, V). I also determined emergence patterns of lotic chironomids in southern Finland (II, IV). Timing of sampling was found to be a critical design factor in the application of the CPET, especially if the trophic gradient between study sites was short. Sampling occasions need to match with the emergence periods of indicator chironomid taxa to ensure the maximum likelyhood of detecting human impacts, if any exist. However, the optimal timing of sampling varies spatially and is dependend on several environmental factors, such as latitude, altitude and trophic gradient. The shift in taxonomic composition of emerging chironomids was found to be especially rapid in spring, and tended to decrease towards autumn. This was probably due to the short emergence periods of some spring-emerging univoltine species, with their annual emergence taking only a few weeks. In contrast to whole genera, the detection of a certain species may require accurate timing of sampling. Thus, among-site differences observed at species level may reflect spatially varying emergence patterns rather than true differences in community composition. On the other hand, because of the among-species variation in species' tolerances towards, for example eutrophication, genus level identification may mask subtle differences between study sites. Nevertheless, for most monitoring purposes genus level identification seems practical and adequate, although species level resolution is desirable. Comparisons of the CPET method and more traditional grab sampling showed that pupal exuvial samples provided a more complete picture of the chironomid fauna, and that this information was obtained cost-effectively. Further, the integrative nature of the CPET was found to be critically important in the assessment of both lotic and lentic habitats. Sampling only a single macrohabitat type may result in biased estimates of the ecological condition of the whole water body. Further, in comparison to profundal grab samples, integrating species from various habitats using the CPET method appeared to have only a minor negative influence on the signal strength. Determination of emergence patterns of lotic chironomids showed that nearly 200 chironomid species occurred frequently in rivers of southern Finland. A major proportion of species richness was accounted for the sub-families Chironominae (emerging mainly during the summer months) and Orthocladiinae (spring and autumn). Overall, these studies demonstrated that the CPET is a cost-effective and sensitive method for the assessment and monitoring of freshwaters, and should be considered as an alternative and/or supplementary tool to more traditional sampling methods.

The objectives of this study were to characterise macrozoobenthic community structure of the western sector of Algoa Bay, to identify the drivers of community structure and to develop a long-term monitoring framework. Data were collected from six study sites stratified along-shore. Each site comprised three stations; most sites were located in areas directly influenced by anthropogenic activities such as inflow from storm water drains and areas where dredged spoil was dumped. Other sites included areas in close proximity to estuary mouths. Physico-chemical parameters of the water column were measured with a YSI instrument, sediment for faunal and physico-chemical analyses was sampled with a Van Veen grab, and collected macrofauna were sedated and preserved pending analysis. In the laboratory, macrofauna were identified to finest taxonomic resolution possible under dissecting and compound microscopes, and enumerated. Sediment samples for physico-chemical analyses were kept frozen pending analysis. Up to 187 species belonging to 137 genera and 105 families were identified. Univariate community parameters such as abundance and number of species varied significantly along-shore, generally increasing towards less wave-exposed sites. Multivariate analyses revealed that community assemblages were heterogeneously distributed along-shore, corresponding to areas where anthropogenic influences such as effluent discharge and commercial harbour activities prevailed. During the 2008 survey, species assemblages separated into six groups corresponding to the six sites but xvii during the 2009 survey, species assemblages separated into four groups probably due to changes in environmental parameters such as the hydrodynamic regime. In both surveys the assemblage opposite a drainage canal (Papenkuils outfall) was distinct as it was dissimilar to all other assemblages. This site was also heterogeneous over relatively small spatial scales. Important physico-chemical variables influencing community structures during the 2008 survey included bottom measurements of temperature, salinity, dissolved oxygen, coarse sand and mud. During the 2009 survey, only bottom temperature and mud content were identified as important physico-chemical variables structuring community assemblages. The principal variable was probably the hydrodynamic regime, driving community structure at a larger scale in Algoa Bay. On a localised scale, communities were probably structured by other factors such as effluent discharges, influence of estuary mouths and activities associated with the harbour. With a lack of information on keystone species (regarded as good monitoring species) in Algoa Bay, it was proposed that groups that cumulatively comprise 50–75 percent of total abundance within communities be monitored annually. Included are amphipods, polychaetes, cumaceans, ostracods, tanaids and bivalves. It was also proposed that areas opposite estuary mouths, effluent outfalls and the dredged spoil dumpsite be monitored. This routine monitoring programme should be accompanied by periodic hypothesis driven research to assess the importance of stochastic events (e.g., upwelling) on macrozoobenthic community dynamics. Keywords: macrozoobenthos, soft-bottom, community assemblages, spatial distribution patterns, environmental drivers, long-term monitoring framework.