Abstract
This study focuses on the analysis of annual cycles of air-sea CO2 fluxes in the Bay of BouIsmail, Algeria. Through meticulous collection of physicochemical data, such as temperature,
salinity, pH, dissolved oxygen, total alkalinity, chlorophyll and phytoplankton, this research
makes a significant contribution to the understanding of these processes.
The main conclusions of this study are as follows:
In winter, Bou-Ismail Bay functions as a source of CO2 for the atmosphere, characterized by
pronounced vertical mixing and oxygen supersaturation throughout the water column.
In spring, increased photosynthetic activity leads to a decrease in water pH and an increase in
the partial pressure of CO2, thus transitioning the region from acting as a CO2 sink to becoming
a CO2 source for the atmosphere.
During summer, despite higher temperatures, the bay continues to act as a CO2 sink. There is
thermal stratification in the water column, with deeper waters being slightly undersaturated in
oxygen.
These results are crucial in the environmental context of Algeria and contribute to a better
understanding of biogeochemical cycles as well as the potential impacts of climate change on
this coastal region.