Effect of trophic status in the formation of humic substances from the decomposition of aquatic macrophytes.

• Grant number: 13/03989-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: October 01, 2013
• End date: February 28, 2015
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Irineu Bianchini Júnior
• Grantee: Brayan Pétrick de Souza
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Eutrophication is the increase of nutrients in aquatic ecosystems, this event induces changes in primary production and, consequently, may increased biomass of aquatic macrophytes. Whereas the macrophytes represent an essential compartment onnutrientcycling in aquatic environments and their decomposition is an important source of humic substances, the aim of this study is to investigate the influence of trophic status in the formation of humic substances from in situ decomposition of five species (Sagittaria montevidenses, Brachiaria subquadripara, Eichhornia crassipes, Pistia stratiotes and Salvinia auriculata). The effect of trophic status in humification will be verified using incubations (i.e.litter bags) previously realized in reservoirs Lajes (oligotrophic) and Vigário (eutrophic). Periodically, for 120 days, from the detritus remaining in litter bags will be performed extractions of humic substances. The humic substances (i.e. humic and fulvic acids) will be quantified throuth analysis of concentration of total carbon and spectroscopic analysis in the UV and visible region. For this, two methods of extraction of humic substances, from macrophytes detritus, will be tested.