Fatores ambientais influenciando no processo de fracionamento de folhas de espécies de mangue (São Caetano de Odivelas, Pará).

Abstract

The global study of the nutxient cycling of mangrove ecosystem is very important for the knowledge of this productivity. The decomposition processes makes the nutrients available for the organisms. The decomposition rate is a important data to be considered in a nutrient cycling of any ecosystem. Depends of the decomposition velocity, the process will have formation of organic matter, essential for life and the ecosystem stability. This study objective determine the decomposition rate of leaves of different mangrove species, compare the velocity of decomposition and verify the nutrient concentration during the decomposition process at the rainy climate period on two site of different floristic composition. The two sites have the following floristic composition: site I: Rhizophora mangle, Laguncularia racemosa e Avicennia germinans e site II: Rhizophora mangle, Acostichum aureum e Avicennia germinans. The sediments were lightly acids at the two sites, the site I was reduced and the site II was oxidant. The salinity was greater in site I than the site II. The specie Avicennia germinans presented the greater initial contents of nutrients and the decay coefficient (K) than the other species studied in the two sites. The specie with smaller decay coefficient was Rhizophora mangle in the two sites. Then, the difference of floristic composition wasn't an important factor for the decomposition velocity.