2.1. Study area
The study was performed in a mangrove area in Jaguaribe River
(351400600 W/54504200 S), tributary of the Potengi River in Natal,
Rio Grande do Norte, Brazil (Fig.1A). The climate is tropical, with air
temperatures between 20 and 31 C and total precipitation around
1900 mm. The Potengi River is a temporary river (rainy season
MarcheJuly) with a catchment drainage of 3180 km2 (Silva et al.,
2007) receiving wastewaters from Natal and other smaller towns
throughout the year. The estuary is covered by 15.61 km2 of