Si, pour Hennebont, les années 1660 et 1780 sont marquées par une érosion de l'activité commerciale maritime, cette forme de déclin s'inscrit dans un phénomène bien plus vaste de déclassement progressif des petits ports de fond d'estuaire ; dans le cas présent il s’opère au profit de la nouvelle voisine Lorient. Toutefois, celle-ci, apparaissant de prime abord comme une concurrente, peut être également source d'opportunités, fournissant du travail à la main d’œuvre locale et de nouveaux débouchés commerciaux, avec la captation d'une partie des produits traditionnellement exportés (bois, produits alimentaires...). D'autre part, des liens unissant Compagnie des Indes et artisans locaux s'établissent (fourniture de clous ou d’ustensiles en étain par exemple). Les négociants hennebontais savent également saisir les nouvelles opportunités que leur offre le commerce outre-mer ; s'ils gardent la main sur leurs activités traditionnelles, la Compagnie devient une nouvelle interlocutrice qu'il est intéressant de satisfaire et offre des opportunités d'investissements lucratifs. Prenant en main les destinées d'Hennebont, à travers la Communauté de Ville transformée en caisse de résonance de leurs intérêts, ils lancent une politique de grands travaux, permettant au port de devenir un outil plus efficace et jettent un nouveau regard sur la ville. Ouverture au monde et influence de la ville voisine ont des incidences sur la vie quotidienne de la population à travers la consommation de nouveaux produits, les métiers, la circulation des idées et des techniques notamment de soins, favorisant également la présence de minorités. / If, for Hennebont, 1660s and 1780s were marked by an erosion of the maritime business, this form of decline is part of a much broader phenomenon of gradual decommissioning of the small ports of estuary background; in this case it is for the benefit of the new neighbour Lorient. However it, appearing first as a new competitor, can also be a source of opportunities, providing work for local labor and new market opportunities, with the capture of some of the products traditionally exported (wood, food...). On the other hand, there’s also new links between East India Company and local craftsmen (provision of nails or utensils in Tin, for example). Hennebontais traders know also seize new opportunities that offers them trade overseas; If they keep the hand on their traditional activities, the company becomes a new interlocutor that it is interesting to satisfy and which offers lucrative investment opportunities. Taking in charge the destiny of city, traders transformed the city council to their advantage, they launch a policy of major works, allowing the port to become a more effective tool and take a new look on the City. Opening to the world and the influence of the nearby town also have an impact on the daily life of the population through consumption of new products, the trades, the movement of ideas including care, promoting the presence of minorities.

The primary production of Spartina maritima, the dominant macrophyte of the intertidal salt marshes of the Swartkops estuary, was determined for inclusion into the proposed ecosystem model. Several methods for measuring net production devised for North temperate Spartina species were used, as no single method was considered reliable for the local species. In addition, a new method was devised to take into account the aseasonal growth behaviour of S. maritima . Most energy for growth appears to be directed into leaf production, rather than shoot growth. Live net production values were 523-680 g m⁻²‚ yr ⁻¹, which are generally lower than estimates of N. American Spartina species. Total Live production of S. maritima for the whole Swartkops estuary was 495,6 x I0³kg yr ⁻¹, which is an estimation of potential food resources. Formation of S. maritima detritus by decomposition was significantly related to air and water temperatures. Thus detritus production showed a wide seasonal variation about a mean of 374 g m⁻² yr⁻¹. The total S. maritima detritus production of 307,5 x I0³kg for the whole Swartkops estuary was determined as an estimate of available food resources. Export of detrital material from Spartina marshes to estuarine waters was negligible. Even during a maximal Equinoctial tide, only 6,26 dry g m⁻² detritus was exported from the creek catchment area of Spartina stands. This study has shown that concepts evolved for North temperate estuaries should be carefully considered before being applied to local situations, particularly in view of the relatively low, aseasonal production of S. maritima and the negligible contribution of its detritus to estuarine waters. Furthermore, it is essential that utilisation of primary production by secondary producers be determined before the function of the estuarine ecosystem may be understood

The Bushmans Estuary is one of the few permanently open estuaries in the Eastern Cape that is characterized by large intertidal salt marshes. Freshwater inflow to the estuary has decreased as a result of abstraction by more than 30 weirs and farm dams in the catchment. The mean annual run-off is naturally low (38 x 106 m3 y-1) and thus abstraction and reduction of freshwater inflow to the estuary is expected to cause a number of changes. The aims of this study were to determine the current health/status of the estuary based on the macrophytes and microalgae and identify monitoring indicators for the East London Department of Water Affairs, River Health Programme. Changes in the estuary over time were determined from available historical data which were compared with present data. This analysis showed that under normal average conditions freshwater inflow to the estuary is very low, less that 0.02 m3 s-1 most of the time. Under these conditions the estuary is in a homogenous marine state. Vertical and horizontal salinity gradients only form when high rainfall and run-off occurs (> 5 m3.s-1). Salinity gradients from 30.1 PSU at the mouth to 2.2 PSU in the upper reaches were measured in 2006 after a high flow event. However the estuary quickly reverted back to its homogenous condition within weeks after this flood. This study showed that freshwater inflow increased nutrient input to the estuary. Total oxidised nitrogen (TOxN) and soluble reactive phosphorus (SRP) concentrations were higher in August 2006, after the flood, than during the other low flow sampling sessions. TOxN decreased from a mean concentration of 21.6 μM in 2006 to 1.93 μM in February 2009. SRP decreased from 55.3 μM to 0.2 μM respectively. With the increased nutrient availability, the response in the estuary was an increase in phytoplankton biomass. After the 2006 floods the average water column chlorophyll-a was 9.0 μg l-1, while in the low freshwater inflow years it ranged from 2.1 to 4.8 μg l-1. The composition of the phytoplankton community was always dominated by flagellates and then diatoms, with higher cell numbers in the nutrient-enriched 2006 period. Although the water column nutrient data indicated that the estuary was oligotrophic, benthic microalgal biomass (11.9-16.1 μg.g-1) in the intertidal zone was comparable with nutrient rich estuaries. Benthic species indicative of polluted conditions were found (Nitzschia frustulum, Navicula gregaria, Navicula cryptotenelloides). These benthic species were found at the sites where wastewater / sewage seepage had occurred. Benthic diatom species also indicated freshwater inflow. During the high flow period in 2006 the dominant diatoms were fresh to brackish species that were strongly associated with the high concentrations of TOxN and SRP (Tryblionella constricta, Diploneis smithii, Hippodonta cf. gremainii, and Navicula species). During the freshwater limited period of 2008 and 2009 the benthic diatom species shifted to a group responding to the high salinity, ammonium and silicate concentrations. The species in this group were Nitzschia flexa, Navicula tenneloides, Diploneis elliptica, Amphora subacutiuscula and Nitzschia coarctata. Ordination results showed that the epiphytic diatom species responded to different environmental variables in the different years. Most of the species in 2008/2009 were associated with high salinity, temperature, dissolved oxygen, ammonium and silicate concentrations while the response was towards TOxN and SRP in 2006. The dominant species were Cocconeis placentula v euglyphyta in 2006; Nitzschia frustulum in 2008; and Synedra spp in 2009. The average biomass of the epiphytes was significantly lower in May 2008 than in both August 2006 and February 2009; 88.0 + 17.7 mg.m-2, 1.7 + 0.8 mg.m-2, and 61.8 + 14.4 mg.m-2 respectively. GIS mapping of past and present aerial photographs showed that submerged macrophyte (Zostera capensis) cover in 1966 and 1973 was less than that mapped for 2004. Salt marsh also increased its cover over time, from 86.9 ha in 1966 to 126 ha in 2004, colonizing what were bare sandy areas. Long-term monitoring of the health of the Bushmans Estuary should focus on salinity (as an indicator of inflow or deprivation of freshwater), benthic diatom identification and macrophyte distribution and composition (for the detection of pollution input), and bathymetric surveys (for shallowing of the estuary due to sedimentation).

The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.

Many South African estuaries are currently believed to be generating lower levels of services than they used to in the past due to substantially reduced inflow of river water, among other reasons. The basis by which river water is allocated in South Africa has had to be re-examined. Local authorities are now required to integrate into their development planning sensitivity to the ways estuaries work; the relevant legislation being the Municipal Systems Act No. 32 of 2000. Sound water resource management requires that the benefits and costs of different water allocations be compared and an optimum determined. The Contingent Valuation Method (CVM) is used in this study to estimate the benefits of changing allocations of river water into estuaries. This study builds on a CVM pilot project done at the Keurbooms Estuary in the Southern Cape in year 2000 (Du Preez, 2002). Further CVM studies were conducted at the Knysna, Groot Brak and Klein Brak estuaries (Dimopolous, 2004). The CVM is a valuation technique based on answers given to carefully formulated questions on what people are willing to pay for specified changes of freshwater inflows into estuaries. The CVM depends on there being a close correspondence between expressed answers given to hypothetical questions and voluntary exchanges in competitive markets that would be entered into if money did actually change hands. The fact that it has proved very difficult to establish this correspondence has led to CVM being subject to criticism. However, many aspects of this criticism have been addressed in the form of methods to reduce biases, and the application of the technique has grown steadily in popularity during the past 25 years. Four estuaries, the Swartkops, Kariega, Mngazi and Mngazana, were surveyed as part of this study in order to determine users’ willingness to pay (WTP) for changes in freshwater inflows. Considerable research time was devoted at the estuaries getting to know how things worked around and in the estuaries. The Swartkops estuary is a permanently open system within the Nelson Mandela Bay metropolitan area. The estuary has the third largest salt marsh in South Africa. Its banks are highly developed with residential and industrial property and it is heavily used for both recreation and subsistence fishing by locals. The Kariega estuary is located near the semi-rural town of Kenton-on-sea, between Port Elizabeth and East London. Although it is permanently open, the Kariega estuary has very low inflows of river water. It is mainly used by retired pensioners living in holiday houses at Kenton-on-sea. The Kariega is not heavily used for recreation and subsistence fishing, except during holidays and the festive season because of its proximity to other estuaries such as the Bushmans and the Kleinemond. The Mngazi and the Mngazana estuaries are located in the Wild Coast area of the Eastern Cape, in the Port St Johns Municipal district. The Mngazi is a temporarily open/closed system which does not have high botanical ratings, although it is heavily used by visitors to the well known Mngazi River Bungalows, a highly rated hotel near the mouth of the Mngazi River. The Mngazana estuary is a permanently open system renowned for its Mangrove forests and excellent fishing spots. Both the Mngazi and Mngazana estuaries are located in rural areas and are heavily used by local village residents for subsistence purposes.

The Sundays Estuary is permanently open to the sea and has been described as channel-like along its entire length with a narrow intertidal area (mostly less than 5 - 6 m in width). The estuary experiences regular freshwater inflow with large supplies of nutrients, derived from the Orange River transfer scheme and agricultural return flow. In particular, nitrate concentrations are high as a result of fertilisers used in the Sundays River catchment area. The objectives of this study were to measure microalgal biomass and community composition and relate to flow, water quality and other environmental variables. Surveys in August 2006, March 2007, February, June and August 2008 showed that salinity less than 10 percent mostly occurred from 12.5 km from the mouth and this was also where the highest water column chlorophyll a (>20 μg l-1) was found. Different groups of microalgae formed phytoplankton blooms for the different sampling sessions, which were correlated with high chlorophyll a. These included blooms of green algae (August 2006), flagellates (March 2007), dinoflagellates (June 2008) and diatom species (February and August 2008). The dominant diatom (Cyclotella atomus) indicated nutrient-rich conditions. Green algae and diatoms were associated with low salinity water in the upper reaches of the estuary. Flagellates were dominant throughout the estuary particularly when nutrients were low, whereas the dinoflagellate bloom in June 2008 was correlated with high ammonium and pH. Maximum benthic chlorophyll a was found at 12.5 km from the mouth in February, June and August 2008 and was correlated with high sediment organic and moisture content. Benthic diatoms were associated with high temperature whereas some species in June 2008 were associated with high ammonium concentrations. The middle reaches of the estuary characterise a zone of deposition rather than suspension which would favour benthic diatom colonization. Phytoplankton cells settling out on the sediments may account for the high benthic chlorophyll a because maximum water column chlorophyll a was also found in the REI zone (where salinity is less than 10 percent and where high biological activity occurs) in the Sundays Estuary.

This thesis report is part of a larger thesis project which includes the museum exhibit Changing Tides and the UBC Museum of Anthropology Museum Note No. 13, entitled Changing Tides: The Development of Archaeology in B.C.'s Fraser Delta. This report chronicles the planning and production of this exhibit project and outlines the criteria on which it is based. The main objective of this project was to aid in the development of public appreciation for scientific archaeology. Justification for this objective is provided through a discussion of the role of public interpretation in archaeology. Funding, exhibit development, exhibit co-ordination and scheduling, exhibit conservation, Museum Note development, and related activities are discussed and evaluated. A series of appendixes are included which document the development of Changing Tides. / Arts, Faculty of / Anthropology, Department of / Graduate

Recent geomorphic and hydrologic environments of a mid-latitude alpine basin are investigated under the integrative theme of paleohydrology. The aims of this research are: 1) to characterize the response of selected biological and geophysical elements to recent climatic change; 2) to determine the resolution and length of paleoenvironmental records in the study area; and 3) to ascertain the significance of observed and inferred environmental change over the Little Ice Age interval. Bella Coola River drains 5050 km² of glacierized mountains along the central coast of British Columbia. Biological elements examined on a basin-wide scale included: tree-growth in temperature and moisture-stressed environments, damage to trees in glacial and fluvial settings, pollen variations in a variety of sedimentary deposits and soil development. Geophysical elements include primarily glacio-lacustrine and floodplain sediments, glacier deposits and river channel morphology. A retrospective strategy was adopted by testing initially for the nature of relationships between synoptic climate, basin hydrology and element response during the period of instrument record (1900 AD to present). Inferences about pre-instrument environments were then made using the proxy data. Events of several types are characteristically mixed in a response record. Variations in Douglas and subalpine fir growth, glacio-lacustrine sedimentation rates, glacier fluctuations and shifting of the Bella Coola River reflect a combination of persistent and episodically extreme behavior. Glaciers appear to respond by advancing or retreating after departures in winter precipitation persistent for several years. Extreme events, particularly high-magnitude autumn floods, are not exclusively linked to a particular set of mean climatic departures. This makes inferences from proxy data such as floodplain deposits and flood-damaged vegetation difficult. Periods of increased flood frequency are supposed to relate to an increase in floodplain sedimentation. Except in very favorable circumstances, paleoenvironmental methods do not have the resolution promised. Climatic information recoverable from tree-ring data and glacio-lacustrine sediments is of considerably lower than annual resolution. Statistically based climate models using proxy data as independent variables produce low levels of explained variance. Proxy data sources in the basin were largely restricted to the last 300 to 4OO years or Little Ice Age interval. Most glaciers in the basin reached Little Ice Age maxima in the middle of the 19th century in response to below average temperatures and above average precipitation between approximately 1800 and 1855 AD. Tree-ring data and equilibrium line altitudes on glaciers indicate that precipitation was on average 25 to 30% greater than the 1951-1980 mean. Inferred below average temperatures in the early l8th century probably signaled the beginning of the Little Ice Age along the central coast; however, there was not a major response in glaciers until persistent positive departures in precipitation occurred. Recession of glaciers from Little Ice Age maxima was slowed by cooler and wetter conditions between I885 and 1900 AD. The persistence of warmer and drier conditions in the first half of the 20th century was exceptional in comparison with inferred climate of the last 330 years. Major floods in 1805/06, 1826, 1885 and 1896 correspond to intervals of increased precipitation. / Arts, Faculty of / Geography, Department of / Graduate

Thesis advisor: Gail C. Kineke / An observational study was conducted from 2013 to 2016 to investigate suspended-sediment transport processes in the stratified Connecticut River estuary. Time-series measurements of velocity and suspended-sediment concentration from the upper estuary were analyzed to determine the relative importance of different processes driving sediment flux under highly-variable river discharge. Results indicate that under high discharge the salt intrusion is forced towards the mouth causing large seaward sediment fluxes throughout the water column. Seaward fluxes are dominated by mean advection, with some contribution due to tidal pumping. Under low discharge the salt intrusion extends to the upper estuary, advancing as a bottom salinity front during each flood tide. Stratification and strong velocity shear during the ebb tide cause the upper and lower water column to become dynamically decoupled. Sediment flux near the bed is landward throughout the tidal cycle despite the net seaward depth-integrated flux, and is almost fully attributed to the mean estuarine circulation. River discharge is the primary factor affecting the magnitude and direction of sediment flux because of its high variability and direct connection to the salt-wedge dynamics. A generalized three-phase conceptual model describes suspended-sediment transport in shallow, stratified estuaries with low trapping efficiencies. First, fine sediment bypasses the estuary during high river flows and exports to the coastal ocean where a portion of this sediment is temporarily deposited outside the mouth. Second, during low discharge offshore mud deposits are reworked by wave- and tidally-driven currents and some sediment is advected back into the estuary with the advancing salt intrusion that transports sediment landward. Third, spatial salinity gradients facilitate sediment transport from the main channel to channel margins, marshes and off-river coves where it is retained and deposited long-term, as demonstrated in prior studies. This re-introduction and trapping of recycled sediment under low-discharge conditions can have important implications for pollutant transport, shoaling of navigation channels and harbors, and salt marsh accretion in the face of rising sea levels. / Thesis (MS) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Atmospheric deposition of nitrogen has been implicated in the destruction of seagrass beds and in the decline of water quality of Tampa Bay, Florida. The objective of this research was to determine the tendency for air masses of different origins to wet-deposit nitrate and ammonium species to the bay. Precipitation chemistry data was obtained via the NADP AIRMoN Gandy Bridge monitoring site for the period of 1 August 1996 through 31 December 2000. Rainfall events were classified by using the NOAA HYSPLIT trajectory model, precipitation chemistry data, and tropical storm history data. Average nitrate and ammonium concentrations and nitrogen fluxes were calculated based upon the chosen categories. The average annual nitrogen flux for nitrate and ammonium were 2.1 kg/ha/yr and 1.4 kg/ha/yr, respectively. For trajectory-classified data, the lowest nitrate and ammonium nitrogen fluxes were observed with air masses from the west and south, over the Gulf of Mexico. The highest ammonium nitrogen flux was seen from trajectories from the east, while local trajectories demonstrated the highest average nitrate nitrogen flux. For chemically-classified data, the highest nitrate and ammonium fluxes were associated with the local combustion classification. Rainfall from tropical weather systems deposited lower average nitrate nitrogen fluxes than non-tropical events, but ammonium nitrogen fluxes were the same between tropical and non-tropical precipitation. Even the events representing the cleanest air masses contributing precipitation to Tampa Bay had nitrate and ammonium concentrations more than two times the background concentrations associated with the northern hemisphere.