Atmospheric Deposition over the Aegean Sea and Its Impact on the Seawater Productivity

The role of the atmosphere as an external source of various nutrients and elements of both natural and anthropogenic origin in the Eastern Mediterranean and in particular the Aegean Sea has been investigated by using long-term deposition data collected over a 21-year period at Finokalia, Crete, Greece. Dry deposition was found to be the main mechanism contributing 67% of total insoluble matter flux, 68% of total dissolved inorganic nitrogen (DIN) flux, and 75% of total dissolved inorganic P (DIP) flux. Sediment traps data from 200 sinking particulate matter samples collected at 2 different depths in the seawater column (500 m and 1715 m) in the Cretan Sea (southern Aegean Sea) during a 9-year period (1997–2005) were compared with atmospheric deposition data (simultaneously collected) to assess the role of atmospheric deposition on seawater productivity and mass transfer in the seawater column. Atmospheric deposition was found to play a significant role in seawater productivity of the Aegean Sea by providing essential nutrients and especially N in excess and by facilitating the creation of aggregates between atmospheric dust and biological material and thus influencing their mass transfer to deeper waters by increasing their size and settling velocity.