Drivers of the coastal ocean surface salinity in the Gulf of Naples, Mediterranean Sea, and implications of their climatic trends for the primary production

Abstract

An analysis using a Random Forest algorithm confirms that coastal phytoplankton production in the Gulf of Naples (GoN) is directly influenced by surface water salinity, tied to nutrient-rich freshwater and offshore salty water influxes. Understanding salinity variability in the GoN could help predict chlorophyll and phytoplankton changes.Modeling surface salinity at the coastal Long-term Marechiara point (LTER-MC) links freshwater runoff and the mixed layer's depth, validated by the Random Forest exploration. These elements, freshwater contribution and surface layer stratification, effectively replicate monthly and yearly salinity fluctuations.Freshwater runoff relates to precipitation, while layer stratification involves wind and heat flux. This breakdown offers insight into external influences (precipitation, wind, and heat flux) and internal dependencies (mixing and circulation) governing salinity at LTER-MC.Forecasting GoN's salinity involves assessing atmospheric factors in diverse climate scenarios, potentially impacting phytoplankton populations. Exploring these factors' anticipated impact on salinity can pave the way for understanding future changes in phytoplankton populations.