Recent studies have found that equatorial Atlantic sea surface temperature (SST) variability may be influencing tropical Indian Ocean climate (Kucharski 2009, Wang 2009). Due to the economic and social impact of tropical cyclones, it is important to investigate how an Atlantic-Indian Ocean connection may be affecting tropical cyclone behavior in the southern Indian Ocean. In this study, the International Best Track Archive for Climate Stewardship (IBTrAC) tropical cyclone database is used to derive metrics of tropical cyclone behavior, which are then compared with indices of tropical Atlantic SST variability representing Atlantic Niño, and Benguela Niño events. Changes in tropical Atlantic SSTs are found to coincide with significant differences in tropical cyclone activity for portions of the southern Indian Ocean. In addition, for these same regions, tropical Atlantic SST variability is associated with changes in large-scale atmospheric conditions, including steering flow, low level vorticity, and humidity, typically associated with tropical cyclogenesis, and tropical cyclone track. The changes in steering flow related to both indices of Atlantic SST anomaly are reproduced by an atmospheric model. The changes in steering flow are also found to be linked to changes in TC translational velocity, and TC tracking. These findings indicate a possible link between tropical Atlantic conditions and cyclone activity in the Indian Ocean mediated through a teleconnection between tropical Atlantic SSTs and large scale atmospheric conditions over the southern Indian Ocean. The teleconnection related to the Benguela Niño region of SST variability was found to consist of a Rossby wave initiated off the coast of South America, and propagating into the Indian Ocean, thereby influencing several atmospheric variables, including steering flow. The teleconnection related to the Atlantic Niño region of SST variability was not well defined, although there was some evidence of a Walker circulation anomaly extending from the equatorial Atlantic over the continent of Africa, and influencing SIO steering flow. / Graduation date: 2012

This study reconceptualises Sri Lanka's external trade and interactions from the middle of the first millennium BC to the early second millennium AD. Unlike earlier analyses, mine draws on the excavated material culture from three port-cum-urban centres - Mantai, Kantharodai and Kirinda - which were linked to major urban complexes, interior resource bases and Indian Ocean maritime networks. The scale and intensity of their external trade and connectivity, crafts and industries varied greatly over time and location. My findings illustrate Sri Lanka's earliest cultural-commercial connections with India from the middle of the first millennium BC. By the beginning of the CE, islanders were trading with the Middle East and the Mediterranean in the west and Southeast Asia and China in the east. The Middle East was a particularly strong connection from about the mid-3^rd century. Materials from Southeast Asia and China arrive by the late 7^th/8^th centuries, with the focus of external trade shifting away from the Middle East to the Far-East around the end of the 10^th century, lasting until the 12^th/13^th centuries and beyond. My findings demonstrate that internal developments in irrigated agriculture, iron technology, crafts, industries and procurement-distribution networks were crucial for external trade and connectivity. Contrary to the traditional view, I identify local agency as an important driving force behind both internal and external trade in ancient Sri Lanka. The island's external connectivity did not depend on a single factor but was based on specific historical realities which were constantly redefined and reformulated in response to the changing dynamics within and outside Sri Lanka.

University of Macau / Faculty of Social Sciences and Humanities / Department of Government and Public Administration

This study conducted the first high-resolution investigation of the ichthyofaunal assemblages on a high-latitude coral reef in the Western Indian Ocean (WIO). Two-Mile reef, in South Africa, is a large, accessible patch-reef, and was selected as a candidate study area. Although the effect of season in structuring coral reef fish communities is most-often overlooked, the relationship between these fish communities and their habitat structure has been investigated. In South Africa, however, neither of these potential community-level drivers has been explored. As coral reefs worldwide are faced with high levels of usage pressure, nondestructive underwater visual census (UVC) techniques were identified as the most appropriate survey methods. This study had two primary aims that were; (1) to identify the most suitable technique for the UVC of coral reef fishes, and to test variations of the selected technique for appropriateness to implementation in long-term monitoring programs, and (2) to determine if possible changes to ichthyofaunal community structure could be related to trends in season and/or habitat characteristics. A review of the literature indicated that the most appropriate UVC method for surveying epibenthic coral reef fishes is underwater transecting. To compare the traditional slate-based transects to variations that implement digital image technology, slate transects were compared to a first-attempt digital photographic transect technique, and digital videographic transects. Videographic transects produced the most favourable species richness, abundance, and standard deviations of the three techniques. Diversity was not significantly different between transect techniques. The minimum required sample size was lowest for videographic transects (17 replicates), intermediate for photographic transects (27 replicates) and highest for slate transects (37 replicates). Videographic and photographic transects required greater analysis time to generate counts, but required lower observer training time. While videographic transects produced the lowest proportion of species considered unidentifiable, all three transect techniques showed similar functionality to surveying epibenthic coral reef fishes. Videographic transects were therefore identified as the most appropriate UVC technique for this study. Videographic transects at shallow (6 – 14 m), intermediate (14 – 22 m) and deep (22 – 30 m) depths in mid-winter and mid-summer, sampled a total of 41 families consisting of 209 species and 18172 individuals, dominated by pomacentrids in abundance and labrids in richness. The fish assemblages on Two-Mile Reef were found to be similar in composition to lower-latitude WIO reefs. Overall ichthyofaunal abundance and richness was significantly higher in summer than in winter, and was higher at shallow sites than at intermediate and deep sites. A multivariate approach confirmed differences between seasons at shallow depths but not between seasons at intermediate and deep depths. The fish assemblages on Two-Mile Reef can therefore be described as being comprised of four relatively distinct communities: a shallow, winter community; a shallow, summer community; a year-round intermediate community; and a year-round deep community. The distributions of discriminating species indicated that high abundances of the algal-feeding pomacentrids are observed only at shallow and intermediate sites while high abundances of the zooplanktivorous serranid subfamily, the Anthiinae, are observed predominantly at deep sites. Assessment of all measured supplementary variables indicated that of all factor combinations, observed patterns could be ascribed most strongly to depth. Quantification of reef characteristics indicated that as depth increases, habitat complexity decreases, benthic communities shift from dense coral domination to sparse sponge domination, and algal biomass and cover decreases. The ability of the videographic transect technique to detect changes in community structure with season and depth indicates that season and depth should be accounted for in future high-latitude ichtyofaunal surveys, and that the videographic transect technique is suitable for implementation in long-term monitoring programs on coral reefs. The similarity in fish assemblages between Two-Mile Reef and lower latitude regions suggests that the protocol for surveying epibenthic coral reef fishes, resulting from this study, is relevant throughout the continental WIO.

Climatological winds over the equatorial Indian Ocean (EqlO) are westerly most of the year. Twice a year, in April-May ("spring") and October-December ("fall"), strong, sustained westerly winds generate eastward equatorial jets in the ocean. There are several unresolved issues related to the equatorial jets. They accelerate rapidly to speeds over lms"1 when westerly wind stress increases to about 0.7 dyne cm"2 in spring and fall, but decelerate while the wind stress continues to be westerly; each jet is followed by westward flow in the upper ocean lasting a month or longer. In addition to the semi-annual cycle, the equatorial winds and currents have strong in-traseasonal fluctuations. Observations show strong 30-60 day variability of zonal flow, and suggest that there might be variability with periods shorter than 20 days in the central EqlO. Observations from moored current meter arrays along 80.5°E south of Sri Lanka showed a distinct 15 day oscillation of equatorial meridional velocity (v) and off-equatorial zonal velocity (u). Recent observations from current meter moorings at the equator in the eastern EqlO show continuous 10-20 day, or biweekly, oscillations of v. The main motivation for the present study is to understand the dynamics of intraseasonal variability in the Indian Ocean that has been documented in the observational literature. What physical processes are responsible for the peculiar behavior of the equatorial jets? What are the relative roles of wind stress and large scale ocean dynamics? Does intraseasonal variability of wind stress force intraseasonal jets? What is the structure and origin of the biweekly variability? The intraseasonal and longer timescale variability of the equatorial Indian Ocean circulation is studied using an ocean general circulation model (OGCM) and recent in Abstract ii situ observations. The OGCM simulations are validated against other available observations. In this thesis, we document the space-time structure of the variability of equatorial Indian Ocean circulation, and attempt to find answers to some of the questions raised above. The main results are based on OGCM simulations forced by high frequency reanalysis and satellite scatterometer (QuikSCAT) winds. Several model experiments with idealized winds are used to interpret the results of the simulations. In addition to the OGCM simulations, the origin of observed intraseasonal anomalies of sea surface temperature (SST) in the eastern EqlO and Bay of Bengal, and related air-sea interaction, are investigated using validated satellite data. The main findings of the thesis can be summarized as: • High frequency accurate winds are required for accurate simulation of equatorial Indian Ocean currents, which have strong variability on intraseasonal to interannual time scales. • The variability in the equatorial waveguide is mainly driven by variability of the winds; there is some intraseasonal variability near the western boundary and in the equatorial waveguide due to dynamic instability of seasonal "mean" flows. • The fall equatorial jet is generally stronger and longer lived than the spring jet; the fall jet is modulated on intraseasonal time scales. Westerly wind bursts can drive strong intraseasonal equatorial jets in the eastern EqlO during the summer monsoon. • Eastward equatorial jets create a westward zonal pressure gradient force by raising sea level, and deepening the thermocline, in the east relative to the west. The zonal pressure force relaxes via Rossby wave radiation from the eastern boundary. • The zonal pressure force exerts strong control on the evolution of zonal flow; the decel eration of the eastward jets, and the subsequent westward flow in the upper ocean in the presence of westerly wind stress, is due to the zonal pressure force. • Neither westward currents in the upper ocean nor subsurface eastward flow (the ob served spring and summer "undercurrent") requires easterly winds; they can be gener ated by equatorial adjustment due to Kelvin (Rossby) waves generated at the western (eastern) boundary. • The biweekly variability in the EqlO is associated with forced mixed Rossby-gravity (MRG) waves generated by intraseasonal variability of winds. The biweekly MRG wave in has westward and upward phase propagation, zonal wavelength of 3000-4500 km and phase speed of 4 m s"1; it is associated with deep off equatorial upwelling/downwelling. Intraseasonal SST anomalies are forced mainly by net heat flux anomalies in the central and eastern EqlO; the large northward propagating SST anomalies in summer in the Bay of Bengal are due to net heat flux anomalies associated with the monsoon active-break cycle. Coherent variability in the atmosphere and ocean suggests air-sea interaction.

Univ., Diss. u.d.T.: Barendse, Rene J.: Koningen, Compagnieën en kapers: de Arabische zeeën 1640 - 1700--Leiden, 1992. / Frühere Ausg. u.d.T.: Barendse, Rene J.: The Arabian seas 1640 - 1700.

Master of Science / Department of Geology / Kirsten Nicolaysen / The Kerguelen Archipelago and the submarine Northern Kerguelen Plateau consist primarily of basalt erupted by the intraplate Kerguelen hotspot. The exposed volcanic rocks are tholeiitic basalts (29 Ma) followed by lesser alkalic basalts, highly alkaline phonolites, and syenites (24 Ma). This study presents the mineralogy, isotopic and geochemical compositions of lavas (n=59) from a 650 m section exposed in the wall of a glacial valley at Trois Menestrels in the Kerguelen Archipelago. This basalt section, exposed south of the Cook Ice Cap and closest to the Raillier du Baty alkalic plutonic complex, is further south and west of previously studied basalts exposed on the Plateau Central. Results of 40Ar/39Ar dating show the Trois Menestrels lavas erupted approximately 25 Ma, approximately contemporaneously with other Plateau Central lavas and thus provide an opportunity to examine spatial compositional variations within the Kerguelen hotspot. Though the Trois Menestrels lavas are tholeiitic, The samples plot on the tholeiitic field at the stratigraphic section of Trois Menestrels, 80% of lavas from Mt. Tourmente are transitional to alkalic in the younger rocks (25.6 Ma). This sequence of tholeiitic to transitional to alkalic compositions is mirrored at Mt. Capitole and Mt. Marion Dufresne. Sr, Ba, Pb, Nb, Zr versus Nb plots show similar patterns across the Plateau Central and abundances overlap within error. Variations in isotopic composition reveal that Trois Menestrels is rather homogeneous compared to the other sections. A fundamental issue that derives from these results is the close relationship between these different rocks of the various region of the Plateau Central.

Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: This study investigated the evolution of the genus Palinurus at the higher and lower taxonomic levels. The population genetics of the spiny lobster, Palinurus delagoae, was investigated by making use of a portion of the mitochondrial DNA (mtDNA) control region (547 base pairs) that was sequenced for 285 lobsters from the southeastern coast of Africa (six sites) and 49 lobsters from Walters Shoals (one site), a submerged seamount on the Madagascar Ridge. Lobsters from these two areas shared no haplotypes and differed by at least 27 mutational steps. An analysis of molecular variance showed significant genetic partitioning, and pairwise comparisons suggested that lobsters from Walters Shoals are distinct from those of other sampling areas. Along the south east African coastline there was shallow genetic partitioning between four southern sites (South Africa) and two northern (Mozambique) sites, suggesting two Management Units along the African coast. Female gene flow along the African coast may be propagated by larval dispersal in the Mozambique and Agulhas Currents and counter-current migrations by benthic juveniles along the shelf, but the mtDNA data strongly suggest that larvae at Walters Shoals have been, or are currently still retained by other oceanographic processes. The magnitude of mtDNA divergence among lobsters from the southeastern coast of Africa and those at Walters Shoals, together with the absence of any shared haplotypes between these regions, strongly suggested that these two taxa represent distinct species. The molecular data of the large subunit ribosomal RNA, 16S rRNA (481 bp), and cytochrome oxidase subunit I, COI (520 bp) were then used for a higher level phylogenetic analysis of the genus. A total of 33 individuals (five representatives from each of the six species), and two outgroups (Projasus parkeri and Palinustus unicornutus), were subjected to maximum parsimony, maximum likelihood and Bayesian inference analyses. All analyses were conducted on both the separate data sets as well as a combination of the two genes. Bootstrap analyses of the 16S rRNA data resulted in >70% support for the monophyly of all six Palinurus species but no support could be obtained for any of the interspecific associations. Likewise, individual analyses of the COI gene resulted in strong support for the monophyly of the species. The combined data (parsimony analyses) increased the resolution considerably and apart from the monophyly of all six species, good bootstrap support was also obtained for associations among species. The topology for the maximum likelihood analyses displayed a more resolved and well supported tree when the basal ingroup taxon P. elephas was used to root the tree. The combined Bayesian analyses did not result in a well resolved topology and no significant posterior probabilities could be obtained reflecting the associations among species. / AFRIKAANSE OPSOMMING: Hierdie studie het die evolusie van die genus Palinurus by hoë en laer taksonomiese vlakke ondersoek. Die bevolkingsgenetika studie op die kreef, Palinurus delagoae, is ondersoek deur gebruik te maak van 'n gedeelte van die mitokondriale (mtDNA) kontrole-area (547 basispare) waarvan die volgorde bepaal is vir 285 krewe van die suidoos-kus van Afrika (afkomstig van ses verskillende gebiede) en 49 krewe afkomstig van Walters Shoals (een gebied), 'n ondersese berg op die Madagaskar Rand. Krewe van hierdie twee areas deel geen haplotipes nie en verskil met ten minste 27 mutasiestappe. 'n Analise van die molekulêre variansie toon dat daar 'n beduidende genetiese verdeling tussen die twee groepe is en 'n gepaarde vergelyking toon dat krewe afkomstig van Walters Shoals verskil beduidend van krewe uit ander gebiede. Volgens die vlak genetiese verdeling tussen die vier suidelike (Suid-Afrika) en twee noordelike (Mosambiek) gebiede van die suidoos-kus van Afrika wil dit voorkom of daar twee bestuurseenhede langs die kuslyn van Afrika is. Vroulike geenvloei langs hierdie kuslyn kan dalk bevarder word deur larwale verspreiding in die Mosambiek- en Agulhas- Seestrome en teenstroom migrasie van jong bodemwonende krefies op die kontinentale plaat. Die mtDNA data stel egter voor dat kreeflarwes by Walters Shoals deur ander oseanografiese prosesse steeds (of tot onlangs toe) behou word. Die grootte van mtDNA divergering tussen krewe van die suidoos-kus van Afrika en die by Walters Shoals, sowel as die afwesigheid van enige gemeenskaplike haplotipes tussen die twee gebiede, toon met beduidende sekerheid aan dat hierdie twee taksa twee unieke spesies verteenwoordig. Die molekulêre data van die 16S-rRNA (481bp) van die groot ribosomale-subeenheid en die sitochroom oksidase subeenheid, COI (520bp) is gebruik om 'n hoër resolusie filogenetiese analise van die genus te bepaal. Data van 33 individue (vyf individue uit elk van die ses spesies) en twee buitegroepe (Projasnus parkeri en Palinustus uniconutus) is geanaliseer deur gebruik te maak van die maksimum-parsimonie, die maksimum-waarskynlikheid en die Bayes-inferensie metodes. Alle analises is uitgevoer op beide die afsonderlike datastelle sowel as op die gekombineerde data van die twee gene. Analise van die 16S-rRNA data deur die skoenlusmetode (steekproefhersteekproef- metode) toon meer as 70% steun vir die monofilie van al ses Palinurus spesies maar dit toon geen steun vir enige van die interspesifieke assosiasies nie. Net so toon individuele analise van die COI geen beduidende steun vir die monofilie van die spesies. Die gekombineerde data (parsimonie) het 'n aansienlike verhoging in die resolusie teweeg gebring en behalwe vir die monofilie van al ses die spesies was daar ook goeie steun deur die skoenlusmetode vir die assosiasie tussen spesies verkry. Die topologie vir die maksimum-parsimonie het 'n goed gesteunde en hoër resolusie boom vir die gekombineerde datastel (sonder die buitegroepe) getoon. Die gekombineerde Bayesanalise het nie 'n soortgelyke boom opgelewer nie en die assosiasie tussen die spesies is nie ondersteun nie aangesien geen beduidende a posteriori-waarskynlikheid verkry kon word nie.

The study involves the investigation of the chemical composition of some marine organisms. This entails collecting the organism, extracting compounds from it and separation, characterization and identification of these compounds. Marine chemistry has been ignored by many scientists in the past and it is for this reason that these organisms have been investigated, with the aim of discovering their chemistry and also finding new compounds which might be of value in our society. Such value may be the medicinal benefit and/or the understanding of some toxicological effect of some species. This study was conducted on Codium extricatum, Palythoa natalensis, Zoanthus sansibaricus and Zoanthus durbanensis all of which were collected from reefs situated at the southern part of Durban in KwaZulu-Natal (KZN). Carpobrotus edulis was another organism that was used in this work. The plant normally occurs on sand dunes. This, however, was collected from the terrestrial environment within the premises of University of Natal (Durban). Sterols, i.e., compound l, 2 and compound 4 were obtained from both the Codium and Zoanthus genera. Zoanthus also gave compounds which are derivatives of genetic material and these include inosine nucleoside, adenine nucleoside and guanine nucleoside. Zoanthus further gave a compound which is aromatic in nature i.e., compound 5 and this belongs to a class of compounds known as the tyramines. Cinnamic acid was found from Carpobrotus edulis. The structures of all compounds were elucidated by conducting a number of experiments using spectroscopic methods. These included nuclear magnetic resonance spectroscopy (n.m.r), mass and infrared spectroscopy. / Thesis (M.Sc.)-University of Natal, Durban, 2000.

This thesis aims to explain how British naval power was sustained in the Indian Ocean during the French Revolutionary and Napoleonic Wars. To improve efficiency and economy, the Admiralty had to reorganise the management of shore support services, as well as to rationalise the bases available to the navy to meet the enemy it faced. The basic proposal of this thesis is that British naval power was projected overseas by the Admiralty's effective reconciliation of two competing demands, the naval demand for strategic deployment and the domestic demand for reform. The thesis argues that British naval power in the Indian Ocean was increased by the acquisition of the Cape of Good Hope and Trincomalee and the naval bases built at these locations. The removal of the navy from complete dependence on the East India Company for support services was part of a long term policy of increasing Admiralty control of facilities in the east. In 1793 Bombay was the main naval base but Madras quickly became another hub supporting naval activities in the east. Other locations were considered. Calcutta was used and investigations were made into developing Penang as a navy base before Trincomalee became part of Britain’s long-term naval infrastructure. At the Cape a separate naval command was given responsibility for part of the Indian Ocean. Following the capture of Mauritius in 1810 this island was used temporarily as a forward support base. Admiralty control of the naval support services delivered to the squadrons at the Cape and in the East Indies was dramatically improved by the appointment overseas of resident commissioners from 1809. This resulted from the implementation of the recommendations of the Commission of Naval Revision, first suggested by the Commissioners on Fees in 1788. Resident commissioners ensured Admiralty instructions and policies were implemented and executed, resulting in improved efficiency and reduced costs.