WAVE - INDUCED DEVICES FOR THE OXYGENATION OF DEEP LAYER: A PHYSICAL INVESTIGATION

Abstract

No other environmental variable of ecological importance to estuarine and coastal marine ecosystems around the world has changed so drastically, in such a short period of time, as dissolved oxygen. Coastal surveys in United States and Europe found that a staggering 78 % of the assessed continental U.S. coastal area and approximately 65 % of Europe’s Atlantic coast exhibit symptoms of eutrophication. The 65 % of the coasts counted by Diaz does not take into account inland seas like the Adriatic or Baltic Seas but also for these, eutrophication and consequently anoxia are common problems. In the present study a simple and economic device is proposed to enhance vertical mixing processes and to induce aeration of deep water by pumping of oxygen-rich surface water downwards to a desired depth around the halocline. The hydrodynamic parameters of the device are estimated through free oscillation tests. Preliminary values of the downward water flux velocity inside the device and the movements of the floater under the action of 4 regular waves, characterizing of the wave climate in the Nord Adriatic Sea, are estimated.