On the use of validated ocean models to investigate the evolution of primary productivity in the Levantine Sea

Abstract

Marine ecosystems are vital natural resources that contribute to the global biogeochemical cycle, food, and energy production. In order to monitor and evaluate variations of different factors for decision making processes, validated ecosystem models were used in this study to analyze the evolution of different variables: temperature and salinity concentrations (from 1987 to 2014) and nitrate, phosphate, dissolved oxygen, chlorophyll concentrations, and phytoplankton biomass (from 1999 to 2014) in four sites (from 0 to 66 m depth) along the Levantine Sea: Lebanon, Turkey, Egypt and in the Open Sea. Principal component analysis and TRIX were then applied. Spatio-temporal analysis and PCA results showed that phytoplankton biomass is temporally affected by temperature and nutrients (in all stations) as well as salinity in some cases, in addition to its decrease with depth. TRIX analysis showed that all stations had higher primary productivity, in the first half of the year (January-May). Intense anthropogenic activities in Turkey and Egypt have altered the ecosystem’s stability and affected the phytoplankton biomass.

Evolution of primary production and its drivers on the Lebanese coast between 1986 and 2013

“…Ecosystems are dynamic systems and the study of their evolution requires the development of models in order to study the complex physicalbiogeochemical interactions between the atmosphere and the surface ocean controlling marine ecosystems (Kanj and Fadel 2020). Meanwhile aquatic ecosystems and phytoplankton can be monitored by costly field sampling and laboratory analysis or by remote sensing that can be limited by cloud cover (El Hourany et al 2017;Ghoussein et al 2019;Pinardi et al 2018;Sharaf et al 2019).…”