The hydrography of the Chupa Estuary, White Sea, Russia

12 páginasThis study was undertaken to determine the fate and fluxes of materials from Arctic estuaries to the coastal zone. The paper is the first of a series addressing questions relating to the physics and chemistry of the region. Three seasonal cruises were undertaken in the Chupa Estuary, White Sea, Russia; in summer (July 1994), autumn (September, 1995) and spring (May/June 1997). The Chupa is a fjord type estuary about 37 km long with several deep troughs, connected by shallow sills, situated south of the Arctic circle on the western shore of Kandalaksha Bay. Vertical profiles were carried out on an axial grid of 10 stations, at spring and neap tidal states, during which measurements were made of salinity, temperature, current speed and direction, the concentration of suspended particulate material (SPM), pH, dissolved oxygen, nutrients (phosphate, silicate, nitrate, nitrite and ammonia) and particulate trace metals in sediments and SPM (Millwardet al., 1999, Estuarine, Coastal and Shelf Science,48,13–25). Additionally, sampling for the hydrodynamic determinants was carried out on diurnal anchor stations at key points in the estuary. Vertical stratification was pronounced, particularly in summer, with sharp gradients in temperature and salinity. A three layer vertical structure was observed with surface (0–5 m) and deep (20–65 m) water layers providing net down-estuary transport while the intermediate (5–20 m) water layer drives net up-estuary transport and advection of more saline waters into the estuary. Strong internal waves were observed in the seaward half of the estuary at certain tidal states. The mechanism for renewal of deep waters in the troughs was investigated, this being considerably slower than in the near surface waters. Evidence of under-saturation of dissolved oxygen was evident in the deep waters of the troughs during the three surveysPeer reviewe

Zooplankton abundance and vertical fluxes of sedimentary matter and chemical elements in the White Sea from 15 to 24 June, 2000

A multidisciplinary oceanographic survey of the White Sea was carried out in the Gorlo Straight, Basin, and Kandalaksha Bay regions including estuaries of Niva, Kolvitza and Knyazhaya rivers. Hydrophysical study in the northern part of the Basin revealed long-lived step-like structures and inversions in vertical profiles of temperature and salinity, which formed due to tidal mixing of saline and cold Barents Sea waters and warmer White Sea waters in the Gorlo Straight. Biological studies revealed the main features of spatial distribution, as well as qualitative and quantitative composition of phyto- and zooplankton in all studied areas; tolerance of main zooplankton species to fresh water influence in estuaries was shown. Study of suspended matter in estuaries clearly demonstrated physicochemical transformations of material supplied by the rivers. Data on vertical particle flux in the deep part of the Kandalaksha Bay showed difference between the upper and near-bottom layers, which could result from sinking of spring phytoplankton bloom products and supply of terrigenic suspended matter from the nepheloid layer formed by tidal currents