Coccolithophores are a biogeochemically important phytoplankton group, fulfilling an important role in the global carbon cycle through primary production and the formation and export of calcium carbonate. Despite this biogeochemical importance, relatively little is known about their ecophysiology, for example their response to nutrient availability in terms of both macronutrient (nitrate, phosphate) and micronutrient (trace metal) or how this impacts on their competition with other phytoplankton groups (e.g. diatoms, Synechococcus). Hence, this study investigated the response of coccolithophores to trace metal (iron, zinc and cobalt) additions in the high latitude North Atlantic (Iceland and Irminger basins) and the Southern Ocean (Great Calcite Belt, Scotia Sea). The response of coccolithophores to environmental conditions was investigated by examining distribution patterns in situ and in targeted bioassays where natural communities were incubated with elevated levels of trace metal concentration. The wide range of initial conditions for these bioassays (e.g. temperature, macro- and micro-nutrient availability and phytoplankton community composition), provided valuable insights into coccolithophore responses to trace metal addition across a range of different biogeographic regions. These responses were investigated in terms of coccolithophore cell abundances, species composition, calcite production and growth rates, and were contrasted with responses of the total phytoplankton community (chlorophyll α) and abundances of diatoms and other phytoplankton groups (e.g. Synechococcus). The major finding of this thesis is that iron addition positively enhances coccolithophore growth rates and calcite production in both the Northern and Southern subpolar oceans. Another significant finding was that zinc addition also positively enhanced growth rates of coccolithophores (and diatoms) in a number of bioassays across the Great Calcite Belt (Southern Ocean). Thus, the trace metals iron and zinc are important micronutrients to consider in regulating coccolithophore growth and calcite production. As climate change potentially altering the flux of such trace metals to the ocean it is therefore important to further investigate the role of these micronutrients in regulating coccolithophore communities and their biogeochemical impact.

Internationally, shipping, boating and ancillary services are seen as significant contributors to degradation of the marine environment, affecting water quality, habitats and coastal amenity. As a result, it is important to ensure good practice with regard to safety issues when discharging or handling such wastes while vessels are in the port's jurisdiction. The international standards for regulating the prevention of marine pollution through ship generated waste are clearly outlined primarily in the United Nations Convention on the Law of the Sea 1982 ("UNCLOS") and the International Convention for the Prevention of Pollution from Ships1973 as amended by the Protocol of 1978 ("MARPOL 73/78"). The proposed study will explore compliance to MARPOL 73/78 Convention's requirement for governments to ensure the provision of adequate port reception facilities capable of receiving ship board residues and mixtures, containing oil, noxious liquids or garbage, without causing undue delay. The paper further reviews the implementation of the Conventions in the European Union and South Africa as it aims to provide a profile of the availability of waste reception facilities to assess their effectiveness in addressing the problem of marine pollution through ship generated waste. It is concluded that a variety of South African legislation is also applicable to marine pollution, but inadequately enforced. Further, that there was a considerable range of legislation intended to protect the North Sea and European waters in general from marine pollution but marine pollution from vessels is still considered to be a significant problem. In conclusion, it is recommended that South Africa should urgently develop effective mechanisms to monitor the enforcement oflegislation adequately. / Thesis (M.Com.)-University of KwaZulu-Natal, Durban, 2010.