Decomposition rate of Rhizophora mucronata leaf litter and identification of fungi in mangrove ecosystems in Pulau Sembilan, Pangkalan Susu District, Langkat Regency

Abstract

Mangrove leaves that fall to the ground play an important role in transferring organic matter from plants into the soil. Organic matter from leaf decomposition is important for mangrove growth and as a food source for ecosystems in the surrounding waters. This study aims to determine the rate of decompositionof Rhizophora mucronate leaves, thelevels of carbohydrates and proteins contained in the decomposed leaves, and the species of fungi present in the leaves. Research samples were taken from mangrove forest areas in Pulau Sembilan, Pangkalan Susu District, Langkat Regency, decomposition rate testing and fungi identification were carried out at the forest cultivation laboratory, Faculty of forestry, University of North Sumatra. The research was conducted from June to December 2022. The results showed that the decomposition rate was 5.9 and there were 5 species of fungi found in the leaves that had undergone decomposition, namely Aspergillus niger, Aspergillus oryzae, Aspergillus fumigatus, Aspergillus glaucus, Aspergillus clatavus. The carbohydratecontent decreased during decomposition, with the highest content in the control on day 30 at10.7% and at the end of the 90th day observation only 1.89%. The remaining leaf litter of R.mucronata was 9.16 g with a weight loss of 30.84 g and a decomposition rate percentage of 22.89% on day 15 had the lowest weight loss of leaf litter, the remaining leaf litter was 22.86g with a weightloss of 17.14 gand a decomposition ratepercentage of 57.15%.