Marine climate in Trondheim Fjord analyzed by hydrographical data collected during 1963-2005
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- Institutt for biologi 
As a result of the investigation of long-time series of hydrographical data, the higher salinity in the Trondheim Fjord was observed in summer, and the data showed rising salinity with increasing depth. The result also revealed that the highest salinity was observed in 1971. Moreover, the lowest salinity was recorded in April.Although the mean inflow of AW to the fjord is not accurately known, the fjord has obviously received a substantial amount of warm and high-saline AW. The deeper waters of the fjord consist of eater of relatively pure Atlantic origin. The hydrography of the fjord is influenced by the hydrographical conditions of the surrounding water masses, Atlantic Water and Coastal Water. Compared to the Svinøy section, the Trondheim Fjord exhibited a corresponding yet lagging pattern. The result suggests a possibility of predicting conditions in the fjord one year ahead by looking at the hydrographical pattern at the Svinøy section.The gradually increasing temperature and enhanced salinity observed in the fjord could largely affect the marine organisms living in it. In order to reduce the effect of marine climate change in Norwegian Fjord the following future research is needed. a. To enhance the understanding of estuarine circulation and hydrodynamic situations (temperature, salinity, oxygen concentration and stratification) and how they respond to regional climatic responses.b. To get know the detailed property and influence of large climatic forcing in Trondheim Fjord and develop hydrographical scenario.Generally, the salinity at the same depth at the sampling stations (0 m, 100 m and 200 m) showed a decreasing pattern as we move north ward in the fjord, whereas the temperature was variable temporally and spatially. However, relatively highest temperature at the same depth of all the sampling stations was observed in the southern part of the fjord. Despite large freshwater supply into the fjord comes from the western and south western part, the salinity minimum was observed in the northern region of the fjord. This may lead to a conclusion; as we go northward (as the latitude increases) the effect of AW in the hydrography of the local area was small. Additionally, the salinity at the whole column of water in Trondheim Fjord was comparatively higher during NAO negative (summer) and lower in NAO positive (winter).