Relative importance of nitrogen and phosphorus emissions from shrimp farming and other anthropogenic sources for six estuaries along the NE Brazilian coast

摘要: Abstract Shrimp aquaculture is a recent development of the Brazilian agribusiness but has increased by about 20% per year during last decade along semi-arid NE coast due to optimal climate and environmental setting. The activity been blamed cause several impacts mostly associated with emission large amounts N P estuaries. Here we estimate, using an factor approach, annual emissions from intensive shrimp farming other anthropogenic sources natural processes six estuaries Rio Grande do Norte State, Brazil, where 40% area country located. Emission factors for (atmospheric deposition soil runoff) are 1 2 orders magnitude lower than those sources. presents largest average (1.9 t km − 2 yr − 1 ), followed agriculture (1.3 ) husbandry (0.7 ). For P, (0.9 (0.34 although also significant unit (0.23 Wastewaters solid waste disposal urban runoff present much area, low level urbanization small population basins. Anthropogenic 20 50 times higher emissions. Agriculture contributes larger fraction (40% 63%) total load three rivers, whereas dominated (64% 74%). contribute loads more populated basin only (35% 11%, respectively). Urban practically negligible in all basins, (less 5% emission), exception Guamare 22% come this source. Aquaculture most important source Acu (58%), pond surface observed. In basins contribution ranges 2% 22%. varying 14%. Notwithstanding covered farms relative or husbandry, location adjacent estuarine areas makes possible direct inputs waters, while go firstly soils before eventually being transported waters. general, hydrochemical proxies nutrient were consistent estimated loads.