The Endeavour segment of the Juan de Fuca mid-ocean ridge is one of the best studied ridge segments and has recently been instrumented as part of Ocean Networks Canada's NEPTUNE cabled observatory. Here we investigate the interaction between high-temperature vent fluids and the overlying water column. A new tow-yo survey found that the average temperature anomaly in the neutrally buoyant plume was 0.0438C. The water column temperature and light attenuation anomalies correlate linearly in some areas of the plume but in other areas there is a low light attenuation anomaly relative to the temperature anomaly. This temperature excess is interpreted to reflect heat input through (particle-poor) diffuse flow. If this is correct, about half of the heat flux along the Endeavour segment comes from diffuse flow. Sediment trap and push core data show that the mass accumulation rate of the hydrothermal component of the sediments decreases rapidly with distance from the major vent fields. Large changes in the composition of the hydrothermal component of the sediments also occur with distance from the vent fields. The composition of the sediments indicates (i) sulfides precipitate early and accumulate most rapidly close to the vents with a preferential order of element removal from the plume of Cd > Ag > Cu > Co Fe; (ii) barite is deposited somewhat further from the vents. Strontium and Pb appear to be strongly incorporated in barite and/or other sulfate minerals; (iii) at most a few percent of the mass of these ''insoluble'' elements that is vented gets deposited within 1.5 km of the vents.

Samples were collected from rainwater, the resulting runoff in urban drainage channels and the Khoshk River (a seasonal river which passes through the city and receives urban drainage channels runoff). Major elements and selected heavy metals (Cu, Pb and Zn) concentrations were investigated for rainwater samples. Marine and non-marine sources of the elements in rainwater were investigated by calculation of Sea salt fraction, Non sea salt fraction and application of factor analysis. pH and mean concentrations of major ions and heavy metals (Cu, Pb and Zn) were compared to the results of similar studies in other countries. GIS interpolation maps indicated the impact of traffic pollution and Shiraz industrial complex on spatial distribution of Cu, Pb and Zn in rainwater. Major ions and Cu, Pb and Zn mean concentrations in runoff samples were also studied and compared to the rainwater results. Since the Khoshk River is the main runoff drainage channel in the city and is used for irrigation, its water quality was also examined.

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