<p>My dissertation project is an ethnographic history of "homes of capital," merchant homes located in port-cities of Gujarat in various states of splendor and decrepitude, which continue to mark a long history of Indian Ocean cross-cultural trade and exchange. Located in western South Asia, Gujarat is a terraqueous borderland, connecting the western and eastern arenas of the Indian Ocean at the same time as it connects territorial South Asia to maritime markets. Gujarat's dynamic port-cities, including Rander, Surat and Bombay, were and continue to be home to itinerant merchants, many with origins and investments around the littoral from Arabia to Southeast Asia. I argue that rather than a point of origin or return, Gujarat's merchants--many of whom are themselves itinerants from Arabia, Persia and Northwest India--produce and produced Gujarat as a place of arrival and departure: as a crucible of mobility. Gujarat's merchant homes offer a model of transregional engagement produced through the itineraries of merchants who continue to see the regions bordering the Indian Ocean as an extension of their homes.</p><p>While historians have generally studied these merchants through the bureaucratic archival records of imperial trade-companies, my project examines the yet-unexplored archives that collect around historic merchant homes. Curated by a current generation of merchant families who continue to ply old routes at the same time as they forge new ones, merchant homes offer a way to study oceanic connections from the inside-out and capital in cultural terms. Drawing on a rich array of collective and personal ethnographic and historical materials within homes, including architectural form; material objects; private journals, datebooks and travelogues; visual media; and merchant memory, my project brings into view a mercantile space-time on ocean's edge. Though emerging from concrete ethnographic and historical materials that cast powerful light on Gujarati merchant mobility in the British Empire over the course of the nineteenth and first half of the twentieth century, my account of "homes of capital" pursues mercantile imaginings across long tranches of time routed through the political economic transformations of the period stretching between the tenth and twelfth centuries. I argue that these non-linear imaginings structured by oceanic mobility exist in the interstices of imperial, colonial and post-colonial state space.</p><p> </p><p>Placing merchant imaginings at the center of my analysis, my dissertation argues that the Indian Ocean was and continues to be a key spatial and temporal motivator of mercantile life. My project makes explicit the terms of this intimacy through a "chronotopic" study of merchant homes across Gujarat. Homes of capital in its broadest sense also include mercantile buildings like bridges, libraries, funerary sites, mosques and community centers, which, when linked together, created shaded pathways across the region in the face of an emergent colonial state centered on Bombay. In doing so I also reveal a more capacious mercantile subject, showing how new kinds of nineteenth-century circulations of Gujarati-language texts across merchant libraries, reading rooms and homes were embedded in and shaped a longue durée oceanic topography. My project documents the range of visual, material, textual and affective modes from within this topography through which merchants gave and give form to such a terraqueous region.</p> / Dissertation

The human-abetted introduction of commensal species (i.e. those that opportunistically exploit the anthropogenic environment for food and shelter, e.g. rats, cockroaches etc.) to new areas has occurred throughout history. This has resulted in detrimental ecological changes worldwide but, from a viewpoint of human knowledge, a beneficial corollary of these translocations is that the species in question can be used as proxies to study the movement of the humans who transported them. I reconstruct colonisation histories of three widespread commensal mammalian species in the Western Indian Ocean, the black rat Rattus rattus, house mouse Mus musculus and Asian house shrew Suncus murinus, through phylogeographic studies (the geographic distribution of genetic lineages) of maternally-inherited mitochondrial markers, and zooarchaeological data. The DNA analyses are conducted on samples largely derived from museum specimens collected up to 110 years ago, and from archaeological bones (in the case of rats). I show considerable cryptic diversity in all three species, particularly in mice for which we find a potential major new lineage. Certain lineages within each species predominantly reveal long-distance translocations within the Indian Ocean, but high resolution geographic and genetic clustering is also evident, particularly in Asian house shrews. Phylogeographic structuring of the three species in East Africa and the southern Indian Ocean region (e.g. Madagascar, Reunion, etc.) indicate connections with Arabia, the Middle East, and India in the Islamic period from the first millennium AD, and later European connections during the Age of Exploration. Closer to the origins of the three species (the Indian subcontinent in all cases), range expansions in Eurasia and nearby islands relate to early to mid Holocene human populations, but also with signals of later secondary colonisations. Through ancient DNA studies I found genetic continuity between temporally separated populations of black rats suggesting population persistence, and high levels of diversity in Songo Mnara, a Swahili stonetown in Tanzania. Knowledge of the colonisation history and genetic diversity of an introduced species is essential to understand their resilience in novel landscapes, and to identify pathways of invasion and, by proxy, human trade and exchange networks that facilitated their dispersal. My research contributes significantly to that end for three socially, economically and ecologically important species that are well-established in the Indian Ocean region and beyond.

Durant de nombreuses décennies, la faune phlébotomienne (Diptera, Psychodidae, Phlebotominae) Malgaches est demeurée très peu explorée. Deux Grassomyia avaient été signalés puis une espèce décrite sous le nom de Sergentomyia berentiensis. A partir des années 2000, la faune de Madagascar a révélé une richesse et une diversité non soupçonnées jusqu'alors avec la description de plusieurs espèces nouvelles et d'un sous-genre nouveau : Vattieromyia. Cette thèse est une contribution à la connaissance des Phlébotomes de Madagascar et des îles voisines des Seychelles et des Comores.Notre approche a été qualitative et non quantitative. Les phlébotomes collectés à Madagascar, aux Comores et aux Seychelles ont été étudiés morphologiquement puis, pour certains d'entre eux, par biologie moléculaire à diverses fins : associations mâles-femelles et systématique évolutive. Dans ce dernier cas, différents marqueurs ribosomiques, mitochondriaux et nucléaires ont été séquencés selon les problématiques.A Madagascar, les Phlebotomus forment un groupe monophylétique. Nous suggérons, sur des arguments morphologiques et moléculaires, de les individualiser dans un sous-genre nouveau étant donnée la mise en évidence de la paraphylie du sous-genre Anaphlebotomus dans lequel ont été classées les espèces malgaches.Nos travaux révèlent que P. fertei possède une aire de distribution qui couvre la presque totalité du pays. Les séquences de cytochrome b individualisent de nombreuses populations selon leurs origines géographiques mais nous n'avons pas pu individualiser ces populations sur le plan morphologique et morphométrique. Les séquences de l'ITS2 n'individualisent pas ces populations et nous critiquons l'utilisation du cytochrome b, et plus largement des marqueurs mitochondriaux, pour la systématique des Phlébotomes.En ce qui concerne les autres espèces de Phlebotomus, elles possèdent toutes une distribution étroite, réduite à leur lieu de capture. Nous avons décrit deux espèces nouvelles durant cette thèse : P. vaomalalae et P. vincenti. Les études moléculaires et morphologiques révèlent l'existence d'au moins trois espèces nouvelles : deux sympatriques à Andranoilovy (dont une espèce commune avec Berenty) et une à Ankililaoka.Enfin, nous proposons le rattachement de P. huberti au genre Sergentomyia. Cette espèce ne possède pas de soies mésanepisternales et le mâle que nous décrivons dans ce travail possède les caractères génitaux des Sergentomyia. De plus, nous décrivons sur une la seule femelle, une espèce nouvelle proche de S. huberti. Une étude moléculaire menée avec d'autres espèces supposées proches (appartenant au sous-genre Sintonius) nous conduit à proposer la création d'un nouveau sous-genre pour classer ces espèces malgaches.Nous analysons la paléobiogéographie des Phlébotomes de Madagascar et envisageons au moins deux épisodes de peuplement : l'un très ancien (environ 120 millions d'années), « africain » datant de la fragmentation du Gondwana et le second, plus récent (65 millions d'années), provenant d'Asie via un pont formé par le plateau des Seychelles.D'un point de vue épidémiologique, la recherche d'ADN leishmanien s'est révélée négative sur tous les phlébotomes testés.Dans l'archipel des Comores, aucun phlébotome n'avait été rapporté. Au cours de trois campagnes de piégeage menées en 2003, 2007 et 2011, nous rapportons la première mention de phlébotomes dans ces îles et décrivons deux taxons nouveaux S. pessoni et S. goodmani comorensis.Aux Seychelles, nous avons identifié S. clydei à Aldabra. Cette population possède des séquences mitochondriales très différentes des nombreuses populations continentales étudiées. L'origine du peuplement de cette île volcanique demeure mystérieuse, sans adéquation avec les données relatives à l'horloge moléculaire du cytochrome b dont nous doutons de la fiabilité. / During the last century, the Phlebotomine sand fly fauna (Diptera, Psychodidae, Phlebotominae) of Madagascar remained largely unexplored. Two Grassomyia were recorded and a species has been described as Sergentomyia berentiensis. From the 2000s, this fauna revealed a richness hitherto unsuspected: it included the description of several new species for Science and of a new subgenus (Vattieromyia). The present study is a contribution to the knowledge of Phlebotomine sand flies from Madagascar and the neighboring archipelagos of the Seychelles and the Comoros.The sand flies collected in Madagascar, the Comoros and the Seychelles were studied morphologically and, for some of them, by molecular biology in order to associate males with females and also to perform molecular systematics. Several molecular ribosomal, nuclear, and mitochondrial markers have been combined.In Madagascar, the Phlebotomus are grouped in a clade. Based on morphological characters and molecular studies, we suggest their individualization in a new subgenus because we show subgenus Anaphlebotomus where the Malagasy Phlebotomus were classified, is paraphyletic.P. fertei exhibits a wide distribution all over country. Sequences of cytochrome b individualize many populations linked to their geographical origins. However, it is not possible to individualize these populations based on morphological and morphometric characters. The sequences of ITS2 do not individualize these populations and we criticize the use of cytochrome b and other mitochondrial markers for the systematics of Phlebotomine sand flies.Regarding the other Malgaches Phlebotomus, all of them have a narrow distribution, reduced to their place of capture. We described two new species for Science: P. vaomalalae and P. vincenti. Moreover, molecular and morphological studies support the existence of at least three new species: two in sympatry in Andranoilovy (probably also recorded in Berenty) and one in Ankililaoka.Finally, we propose that P. huberti belongs to the genus Sergentomyia and not to the genus Phlebotomus. It does not have mesanepisternal setae and the male that we describe here exhibits Sergentomyia's genital characters. Moreover, we described on a female belonging to a new species close to S. huberti. We carried out a molecular study including continental species supposed closely related (belonging to the subgenus Sintonius). It individualizes the Malagasy specimens and consequently, considering their typical pharyngeal armature, we propose the creation of a new subgenus to classify them.We analyze the paleobiogeography of Malagasy sand flies. In agreement with generalized tracks, the settlement of Madagascar followed two routes at different times: one very old (about 120 million years ago), from "Africa" dating from the Gondwana fragmentation and the second, more recent (65 million years), from Asia using a bridge formed by the Seychelles plateau.From an epidemiological point of view, the search of Leishmania DNA was negative in all sandflies processed.In the Comoros Archipelago, no sand fly had been reported in the past. During three field works carried out in 2003, 2007 and 2011, we report the first record of sandflies in these islands and we describe two new taxa: S. pessoni and S. goodmani comorensis.In the Seychelles, we identified S. clydei in Aldabra. This population has mitochondrial sequences highly differing from those of many continental populations processed. The settlement of this volcanic island remains mysterious. They are not in agreement with molecular clock of cytochrome b sequences which seems of doubtful use.

Thesis (MTech (Oceanography))--Cape Peninsula University of Technology, 2009 / A collaborative study between Marine and Coastal Management (MCM) and the Oceanographic Research Institute (ORI) was initiated in March 2001 to investigate the physical oceanography of Sodwana Bay, South Africa, and the affects on coral communities resident to the area. A bottom-mounted Acoustic Doppler Current Profiler (ADCP) and three Underwater Temperature Recorders (UTR) were deployed to complement the long-term monitoring UTR deployed on Nine-Mile Reef (NMR) in 1994. The study was terminated after 30 months, whereby all instruments were removed except for the long-term monitoring UTR.

Após a viagem inaugural de Vasco da Gama, os portugueses traçaram um projeto ambicioso de controle das rotas e dos entrepostos comerciais do oceano Índico, que previa a instalação de feitorias nas cidades africanas costeiras de Quiloa e Sofala. A importância dessa última residia na sua proximidade com os centros produtores de ouro do interior do continente, principalmente o reino do Monomotapa, identificado pelos contemporâneos como o mais rico e poderoso da região. Se no início de sua presença na costa índica os lusitanos aguardaram os mercadores africanos dentro da fortaleza, a partir da queda do volume nos negócios os comerciantes particulares e representantes da Coroa passaram a prospectar o sertão em busca das fontes de riqueza que escapavam da feitoria, desviadas pelas redes mercantis muçulmanas para a cidade de Angoche. Em duas fases distintas, o movimento português em direção ao sertão do continente africano se desenrolou ao longo de todo o século XVI e seus atores produziram grande volume de documentos sobre as diversas características das sociedades com que travaram contato. A partir do vasto conjunto documental, e partindo do pressuposto de que a aplicação de uma metodologia de leitura crítica das fontes nos permitiria acessar, ainda que não em sua totalidade, características das estruturas sociais, políticas e econômicas shona, o objetivo dessa pesquisa é investigar a história política do reino do Monomotapa ao longo do Quinhentos, tendo como ponto de partida a investigação dos interesses que levaram os mutapas a estabelecer relações amistosas com os lusitanos que penetraram em seu território. Ainda que o foco central não seja a presença dos portugueses em África, entendemos que a história do Monomotapa no século XVI somente pode ser compreendida a partir do contato, uma vez que o encontro dos projetos e interesses shona e português provocou o surgimento de novos contextos e arranjos significativos para as dinâmicas históricas dessa região. / After the inaugural trip of Vasco da Gama, the Portuguese have drawn an ambitious project for the control of routes and trading posts of the Indian Ocean, which included the installation of trading stations in the African coastal cities of Kilwa and Sofala. The importance of the latter lays in its proximity to the gold producers in the outback, especially in the Kingdom of the Monomotapa - identified by contemporaries as the richest and most powerful in the region. At the beginning of its presence on the coast, the Portuguese traders waited for African merchants inside the fortress. As the volume of business decreased, the private traders and agents of the Crown began to explore the wilderness due to the seeking of wealth sources that did not reach the feitoria of Sofala. By that time, Muslims had shifted commercial networks for the city of Angoche. In two different phases, the Portuguese movement towards the hinterland of the continent took place throughout the sixteenth century. This research relies on the vast amount of documents left behind by the Portuguese when they passed that encounter . It is based on the assumption that the use of a methodology of critical reading of the sources allows us to approach Shonas political, social and economic structures. Therefore, the purpose of this research is to investigate the political history of the kingdom of Monomotapa throughout the sixteenth century, starting with the research of the interests which led the Mutapas to establish friendly relations with the Lusitanians who invaded their territory. Even though the Portuguese presence in Africa is not our main focus, we understand that the history of Monomotapa in the sixteenth century can only be understood through the analysis of the contact of this people with the Portuguese. This is to say that the projects and interests of the Shona and the Portuguese led to the rise of new contexts and significant arrangements for the historical dynamics in this region.

Esta pesquisa tem por objetivo analisar as características da modernização militar da Índia para o Comando do Espaço e para a Batalha Aeronaval no Oceano Índico. O destaque ao âmbito espacial, aéreo e naval se justifica pela prioridade que o país atribui a esses campos em suas metas de modernização. O conceito base de modernização militar é sintetizado na digitalização das plataformas de guerra para incremento da Consciência de Situação do teatro de operações e para proporcionar capacidade de Ataque de Precisão. Essa ideia é complementada pela constituição de um perfil de forças que tenha massa e pela internalização das tecnologias adquiridas, ou indigenização. A hipótese principal é que a modernização indiana tem se realizado de acordo com um Modelo Híbrido. Em tal modelo há a ênfase nos meios espaciais, aéreos e navais para operações principalmente no Oceano Índico, combinada com a manutenção estrutural e organizacional das Forças Armadas do país. Este padrão é uma convergência do conceito de modernização apresentado pelos Estados Unidos na Guerra do Golfo de 1991 com as necessidades demonstradas após a Guerra do Kargil de 1999, e com os fundamentos tradicionais e a função social das forças militares do país. Do modelo híbrido são derivadas hipóteses auxiliares para o Comando do Espaço e para a Batalha Aeronaval. Em relação ao primeiro caso, atribuiu-se a categoria de Modelo Intermediário Público-Privado, que reflete o nível, a sustentabilidade econômica e o viés social do programa espacial, ajustado aos propósitos militares e regionais do país na Ásia meridional. No segundo, da Batalha Aeronaval, foi empregado o termo Modelo Heterogêneo Defensivo, relativo à conjugação de aeronaves e embarcações de origens e gerações distintas, e ao pragmatismo no estabelecimento de parcerias internacionais para aquisição de plataformas e transferência de tecnologia. A modernização militar indiana tem privilegiado o Comando do Espaço e a Batalha Aeronaval para projetar força em áreas do Oceano Índico, se deslocando de sua área de interesse histórica, a fronteira terrestre com o Paquistão. Como não há uma definição da zona operacional oficial no Índico declarada pelo governo do país, procurou-se defini-la a partir dos documentos doutrinários e estratégicos e das capacidades militares do país. Assim, se estabeleceu uma Área Vital, da qual a Índia depende para a manutenção de suas linhas de comunicações internacionais e crescimento econômico, e uma Área Operacional, onde ocorreria a Defesa Avançada. A modernização espacial e aeronaval, e a atuação na área vital e operacional com redundância de meios têm por objetivo garantir supremacia na porção norte do Índico. / This research aims to analyze the characteristics of the military modernization of India to the Space Command and the Air-Sea Battle in the Indian Ocean. The highlight to the space, air and naval dimensions is justified by the priority that the country concedes to these fields in their modernization goals. The military upgrading core concept is summarized in the digitization of war platforms to increase the Situational Awareness of theater operations and to provide Precision Attack capability. This idea is complemented by the creation of a profile of forces that has mass and the internalization of the acquired technologies, or indigenization. The main hypothesis is that the Indian modernization is performed according to a Hybrid Model. In such a model there is emphasis on space, air and naval assets to military operations primarily in the Indian Ocean, combined with the structural and organizational maintenance of the Armed Forces of the country. This pattern is a convergence of the concept of modernization introduced by US in the 1991 Gulf War with the requirements demanded after the Kargil War of 1999 and with to the traditional bases and the social function of the military forces of the country. Of the hybrid model are derived auxiliary hypotheses for the Space Command and the Air-Sea Battle. Regarding the former, was attributed the category of Public-Private Intermediary Model, which reflects the level, economic sustainability and social bias of the space program, adjusted to the military and regional purposes of the country in South Asia. In the second, the Air-Sea Battle, was used the term Heterogeneous Defensive Model due the combination of aircraft and vessels from different origins and generations, and due the pragmatism in establishing international partnerships to acquire platforms and technology transfer. The Indian military modernization has privileged the Space Command and the Air-Sea Battle to project force in areas of the Indian Ocean, moving away from their historic area of interest, the land border with Pakistan. As there is no official definition of the operational zone in the Indian Ocean declared by the India government, was an objective its definition by considering the doctrinal and strategic documents and the military capabilities of the country. Therefore, it established a Vital Area, of which India depends on to maintain its international lines of communication and economic growth, and an Operational Area, where occur the Advanced Defense. The modernization of Space and Air-Naval assets and the acting in the vital and operational area with military platforms in redundancy aims to ensure supremacy in the northern part of the Indian Ocean.

This study examined patterns of coral reproduction and recruitment on lagoonal reefs adjacent to Mombasa in Kenya, at latitude 4ºS. Very little detailed research has been done on the reproductive patterns of scleractinian corals on equatorial reefs, where it has been suggested that seasonality and spawning synchrony may break down due to the weak environmental cues that are thought to govern the onset and timing of reproduction. Gametogenic data were collected for three faviid (Echinopora gemmacea, Platygyra daedalea and Leptoria phrygia) and three Acropora species (A. tenuis, A. valida and Acropora sp.1) in the Mombasa Marine National Park and Reserve between April 2003 – May 2005. A further 20 species of Acropora were identified (9 species represented range extensions) and marked to examine intra- and inter-specific spawning synchrony within this genus. In comparison to other regions, the overall pattern of coral reproduction in Kenya was found to be asynchronous, with spawning occurring over 9 months of the year from August – April, with some level of ‘temporal reproductive isolation’ occurring between species in relation to the main lunar month and lunar quarter when spawning occurred. Proximate cues governing the timing of reproduction could not be clearly discerned in Kenya with spawning occurring during both rising and maximum temperatures, during both neap and spring tides and across all lunar phases. Acropora species spawned over a 7-month period between October – April and faviid species over a 5-month period from December - April. The timing of reproduction in Acropora varied both within and among species, with the main release of gametes occurring from January – March when sea surface temperatures were at their summer maximum. Individual species released gametes over 2-5 months. The greatest overlap in spawning Acropora species occurred in February, which coincided with the spawning months of P. daedalea and E. gemmacea and suggests that some degree of multispecific spawning is a characteristic of Kenyan reefs. Within the main spawning period individual Acropora species had their main spawning in different lunar months. Acropora species released gametes in all lunar quarters, with the highest number of colonies and species spawning in the 3rd lunar quarter (i.e. in the 7 nights after full moon). Spawning in the faviids was more synchronised than Acropora species with the majority of faviid corals spawning in the 3rd lunar quarter. Single annual cycles of gametogenesis were recorded in E. gemmacea, A. tenuis, L.phrygia, most colonies of A. valida and Acropora sp.1, and in 84% of P. daedalea colonies. Biannual cycles of gametogenesis were recorded in 16% of P.daedalea colonies, which included two morphotypes identified in the Mombasa lagoon through morphometric and genetic studies. The presence of different oocyte sizes in L.phrygia during gametogenesis suggested that in some colonies there were two slightly overlapping oogenic cycles, which terminated in spawning within 1-2 months of each other. Overlapping oogenic cycles have not previously been recorded in hermaphroditic broadcast spawning corals in the tropics. The findings from Kenya support the hypothesis of protracted breeding seasons and a breakdown of spawning synchrony nearer the equator. It is hypothesised that the high fecundities recorded in faviid and Acropora species in Kenya compared to other regions, may allow reef corals to stagger their reproduction over 2-5 months, without incurring a significant reduction in fertilisation rates. Spat from the Family Pocilloporidae dominated settlement tiles in the Marine National Park and Reserve comprising 93.7% of spat, which contrasts with other tropical reefs where Acroporidae spat dominate. Patterns of settlement of Acroporidae spat generally coincided with the timing and extended spawning season in Acropora species in Kenya. The density and relative composition of coral recruits and juvenile corals on natural substrata recorded during this study were similar to those recorded before the 1997-98 bleaching event. There is no evidence to suggest that Kenya’s reefs have undergone a phase-shift in community structure, and reef recovery is occurring post-bleaching with mean percent hard coral cover currently at 25%. The slow rate of recovery of Kenya’s reefs is likely to reflect the scale of the mortality, source and availability of coral larvae as well as post-settlement processes operating at individual sites. In the medium-term, the recovery of Kenya’s reefs appears to be more strongly dependent on larvae from local reefs.

A numerical study is made of the wintertime circulation within the Southeast Indian Ocean (SEIO). The downwelling favourable winds result in a continuous eastward Coastal Current (CC) extending from Cape Leeuwin to the eastern coast of Tasmania, where it forms a confluence with the south branch of the East Australian Current. An additional forcing mechanism for the CC is the Leeuwin Current in the western part of the domain. The study here is divided in two parts: (1) available data and the wintertime averaged results from the Ocean Circulation and Climate Advanced Model (OCCAM) are analysed to provide a first order description of the large-scale circulation; (2) a high resolution model (Princeton Ocean Model) is nested within OCCAM to examine the shelf-slope circulation within the eastern SEIO. The nested model is forced with climatological monthly average winds and several experiments were run to simulate the effects of surface fluxes of density, enhanced bottom friction and stronger winds. In summary, the shelf-slope circulation is governed by a surface south-eastward CC that carries around 2 Sv and reaches velocities of up to 50 cm/s, where the shelf is narrowest. The core of the current is generally constrained to the shelf-break region. Zonal winds and geostrophic control of the CC lead to a transport of 1 Sv through Bass Strait and a north-eastward jet that is directed into the strait between King Is. and Tasmania. Further south, the CC is poleward and known as the Zeehan Current (ZC). Between Cape Leeuwin and Tasmania and over the slope region, a westward current (the Flinders Current) is found at depths of 500-1000 m and has an associated transport of 5-7 Sv. The current is shown to result from a northward Sverdrup transport in the deep ocean. Meso-scale eddies are shown to result from baroclinic instability and have wavelengths of around 250 km and transports of 3-4 Sv, and can dominate the slope circulation. A comparison of the numerical results is also made with two current meter data sets and results show an interannual variability in the ZC strength, that is probably related to ENSO.

Cadmium in the ocean has a nutrient-like cycling pattern: with biological uptake at the surface, subsequent sinking in particulate form and then regeneration as dissolved species in deeper waters. Many measurements have been made over time of the ratio of the concentrations of dissolved Cd to those of PO₄ (Cd/PO₄) in the world ocean and this has become one of the best relationships documented between a trace metal and a nutrient. Combined with the measurements of the Cd/Ca ratio in foraminifera, the Cd/PO₄ ratio has been used to reconstruct the oceanographic circulation patterns that existed during past glacial periods and hence provides information on past climate changes. In the present study Cd/PO₄ ratios of the Southern Indian Ocean in surface and deep waters were investigated. The slopes of the relationships between Cd and PO₄ concentrations in waters of this region are high compared to the global correlations, and lie between those reported for other parts of the Southern Ocean and the Pacific Ocean. In surface waters of the Southern Indian Ocean, Cd/PO₄ ratios decrease from regions exhibiting high nutrient-low chlorophyll (HNLC) characteristic in the south to oligotrophic waters further north. It is also found that particulate Cd plays an important role in regulating the high Cd/PO₄ ratios reported in waters south of the Polar Front. Very low Cd/PO₄ ratios were measured in waters associated with the Subtropical Front southeast of New Zealand compared to other Southern Ocean and global oceanic waters. Seasonal variations in the Cd/PO₄ ratios measured for these waters strongly suggest they are associated with a significant biological uptake of dissolved Cd particularly during the phytoplankton growth season in summer. Dissolved Fe concentrations in the Southern Indian Ocean and seasonal variations of Fe in waters off the Otago Coast (southeast of New Zealand) suggest that Fe may stimulate phytoplankton growth and this might result in lower Cd/PO₄ ratios in surface waters through enhanced Cd uptake relative to PO₄ by the phytoplankton. However there is no distinct relationship between dissolved Fe concentrations and the dissolved Cd/PO₄ ratios measured in these surface waters. This finding is in disagreement with the recent 2006 hypothesis put forward by J.T. Cullen, which proposed that waters exhibiting low dissolved Cd/PO₄ ratios were associated with the HNLC regions. From a consideration of the potential Zn concentrations calculated from Si concentration measurements reported for these waters, it would appear that Zn may play a more important role than Fe in regulating Cd/PO₄ ratios in these waters. Measurements of dissolved and total Cd concentrations relative to those of PO₄ were also undertaken in the Otago Harbour and immediate surrounding coastal waters. These exhibited higher Cd concentrations and higher Cd/PO₄ ratios than open ocean waters further off the Otago Coast. The particulate Cd concentrations showed a negative correlation with Cd concentrations measured in cockle species (Austrovenus stuchburyi) collected in the harbour, suggesting that particulate Cd is not the source of Cd measured in the tissue of this species. The concentrations of Cd and other trace metals were also measured in samples of green mussel (Perna canaliculus), ribbed mussel (Aulacomya atra maoriana) and oyster (Saccostrea cucullata) collected from Otago Harbour and possible correlations explored between these concentrations and other parameters such as the shellfish condition indices and environmental gradients in the harbour. In summary, measurements of dissolved and particulate Cd concentrations in the water column can provide unique information on a number of processes occurring in the global marine environment.

<p>Discoveries in recent years have disclosed the importance of marine cyano-bacteria in the context of primary production and global nitrogen cycling. It is hypothesized here that microbial mats in tropical coastal habitats harbour a rich diversity of previously uncharacterized cyanobacteria and that benthic marine nitrogen fixation in coastal zones is substantial.</p><p>A polyphasic approach was used to investigate cyanobacterial diversity in three tropical benthic marine habitats of different characters; an intertidal sand flat and a mangrove forest floor in the Indian Ocean, and a beach rock in the Pacific Ocean. In addition, nitrogenase activity was measured over diel cycles at all sites. The results revealed high cyanobacterial diversity, both morphologically and genetically. Substantial nitrogenase activity was observed, with highest rates at daytime where heterocystous species were present. However, the three habitats were dominated by non-heterocystous and unicellular genera such as <i>Microcoleus</i>, <i>Lyngbya</i>, <i>Cyanothece</i> and a large group of thin filamentous species, identified as members of the Pseudanabaenaceae family. In these consortia nocturnal nitrogenase activities were highest and <i>nifH</i> sequencing also revealed presence of non-cyanobacterial potential diazotrophs. A conclusive phylogenetic analysis of partial nifH sequences from the three sites and sequences from geographi-cally distant microbial mats revealed new clusters of benthic potentially ni-trogen-fixing cyanobacteria. Further, the non-heterocystous cyanobacterium <i>Lyngbya majuscula</i> was subjected to a physiological characterization to gain insights into regulatory aspects of its nitrogen fixation. The data demon-strated that nitrogenase activity is restricted to darkness, which called upon a re-evaluation of its diazotrophic behaviour.</p>