engleski

Long-term analyses of atmospheric and marine data in the Adriatic basin and observed changes

Environmental changes and anthropogenic disturbance can cause variations in marine ecosystems and marine animal populations. During the last century important alterations in marine animal populations have been recorded and numerous studies suggest that those changes do not depend only on intensity of fishery but also on climate fluctuations. Moreover, it is deduced that ongoing changes could have a stronger and faster effects on small and enclosed seas than other seas and oceans. The Adriatic Sea is small and semi-enclosed basin of the Mediterranean Sea which, as one of the most sampled sub-basin of the Mediterranean Sea, represents an optimal area where to assess effects of ongoing changes on marine ecosystem. It is characterized by winter production of dense water, large river runoff, high biological productivity and episodic events like anoxia, harmful algal blooms and massive mucilage appearances. With its high fish production, it represents one of the richest fishing grounds in the whole Mediterranean. For this reason, long-term analyses of marine and atmospheric historical data have been carried out with the aim to contribute to a better understanding of vulnerabilities and ongoing changes in the Adriatic basin. In order to do that, different datasets have been analyzed, considering in the same time the complexity of available data and interconnections between different parameters. Obtained results show that air and sea temperatures in the Adriatic basin exhibit a significant increase in the last 40 years. Changes in precipitation pattern are detected, together with varying of Po river inflow and salinity variations mostly detected in the surface layer. Seasonal analyses of bio-chemical climatologies show relevant variations, particularly evident in winter season. A general reduction of chlorophyll-a is detected in winter, together with a relevant increase of nutrient concentrations. A decrease of nutrient salts has been detected in summer. Dissolved oxygen values show seasonal changes mainly influenced by sea temperature. A general decrease of pH values has been recorded in all seasons and in all layers, except for spring when higher values reported in area near Po River delta are probably caused by fluctuations of river inflow. Alterations in marine animal species are detected in terms of abundance and geographical distribution. Species showing decrease of abundance indexes in general showed decrease in the extension of distribution area and vice versa, overlapping with environmental changes. Further monitoring and studies are needed in order to understand all linkages and processes of alterations in the Adriatic Sea.

Long-term; Adriatic basin

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