EGU2020-19618, updated on 12 Jun 2020
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Spatio-temporal survey of the coastal carbonate system offshore Lebanon-Levantine Mediterranean Sea

Abed El Rahman Hassoun1, Milad Fakhri1, Majd Habib1,2, Anthony Ouba1, Sharif Jemaa1, Céline Mahfouz1, Houssein Jaber1, Abeer Ghanem1, Mariam Tannous3, and Mohamad El Kheir4
Abed El Rahman Hassoun et al.
  • 1National Council for Scientific Research, National Center for Marine Sciences, P.O.Box 534, Batroun, Lebanon (
  • 2CEREGE, Aix-Marseille Université -CNRS, BP80 cedex4, 13545 Aix en Provence, France
  • 3Faculty of Sciences, Lebanese University, Fanar, Lebanon
  • 4Faculty of Public Health, Lebanese University, Tripoli, Lebanon

The coastal carbonate system regulates the pH of the coastal waters and controls the circulation of CO2 between land-sea interfaces and open sea system. In the context of the ELME (Evaluation of the Lebanese Marine Environment: A multidisciplinary study) project, a seasonal survey of the carbonate system has been started in 2019 through the sampling of 3 different transects starting from the coast towards the open sea, offshore two Lebanese cities (Beirut and Tyre) to evaluate the spatio-temporal variations of this system in coastal areas. The carbonate chemistry is being studied by measuring both total alkalinity (AT) and total dissolved inorganic carbon (CT), together with other critical parameters in coastal ecosystems such as temperature, salinity, pH, dissolved oxygen, nutrients (phosphates, nitrates, nitrites, silicates), and chlorophyll a. The preliminary results show that the highest carbonate system inventories (2546.4 and 2266 µmol kg-1 for AT and CT respectively) were measured in transects influenced by discharges of dumpsite and port areas (offshore Beirut) where positive and significant correlations (p << 0.005) have been recorded with nutrients, particularly with nitrites (> 10 µmol kg-1). Furthermore, TrOCA approach was used to estimate the anthropogenic CO2 concentrations (CANT) below the mixed layer depth. The results demonstrate that all waters in both studied areas are contaminated by CANT, even the deep ones (> 400 m) located in the furthest monitored station, with values greater than 70 µmol kg-1. This fact raises concerns about the effects of such relatively high CANT concentrations on coastal organisms therein. This work presents the preliminary results of an ongoing study. The continuity of this project will help to assess the relationship between land-based anthropogenic pressures and the coastal biogeochemistry in a changing Eastern Mediterranean Sea.

How to cite: Hassoun, A. E. R., Fakhri, M., Habib, M., Ouba, A., Jemaa, S., Mahfouz, C., Jaber, H., Ghanem, A., Tannous, M., and El Kheir, M.: Spatio-temporal survey of the coastal carbonate system offshore Lebanon-Levantine Mediterranean Sea, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19618,, 2020

This abstract will not be presented.