Influence of ocean circulation on phytoplankton biomass distribution in the Balearic Sea: Study based on Sea‐viewing Wide Field‐of‐view Sensor and altimetry satellite data

Abstract

This paper analyzes the spatial time series of surface chlorophyll (Chl) from the Sea‐viewing Wide Field‐of‐view Sensor and sea level anomaly (SLA) from altimetry satellite data from July 2002 to December 2007 in order to characterize the influence of the regional circulation on the phytoplankton biomass in the Balearic Sea. Correlations between Chl and SLA at seasonal and interannual time scales were examined using the singular value decomposition (SVD) method of the cross‐covariance matrix between Chl and SLA. Both seasonal cycles are negatively correlated in the whole basin, indicating that the nutrient availability in the surface layer for biological uptake is associated with the changes in the water column stratification. The coupled patterns, by applying the SVD method to Chl and SLA deviations from their seasonal cycles, identify three distinct biological responses to the circulation. The first pattern (explaining 70% of the covariance between Chl and SLA) indicates Chl enhancements around the Balearic Islands related to the Balearic current reinforced by the Northern current. The second pattern (12% of the covariance) shows that the peninsular coast is rather isolated from the regional surface circulation and its behavior is determined by the Ebro river discharges and land runoff. The third pattern (9%) represents higher Chl values along the peninsular slope and lower Chl around the Balearic Islands linked to the Northern current crossing the Ibiza channel without feeding the Baleric current.