Characterization of the new status of Nador Lagoon (Morocco) after the implementation of the management plan

Abstract

The present study was carried out in 2011 with the aims of (1) evaluating the changes in sedimentary distribution that occurred in Nador lagoon seabed (Morocco) after the implementation of the lagoon management plan in 2009; and (2) characterizing its new sedimentary status in 2011. Due to the lack of a baseline, we used the 1992 sedimentary status for comparison. The seabed surface sediment distribution showed a great change between 1992 and 2011. We found the same four sediment facies, which were present in 1992, namely: mud, sandy mud, muddy sand, and fine sand. However, in 2011, mud covered more than 54% of the lagoon seabed surface, mostly located in the middle part of the seabed, whereas in 1992, more than 80% of the lagoon seabed was covered by sandy mud. The sediments' characteristics showed moderately to poorly sorted facies (S0), ranging between platykurtic and leptokurtic (SK) and with various symmetry indices (SG). The organic matter content in sediment has strongly decreased, from values higher than 20% in most areas in 1992 to a mean value of 3.9% in 2011, ranging from 0.2% to 10.4%, thus confirming that the management actions implemented in 2009 were likely effective in reducing the organic pollution.