Detritus degradation and water quality in water sources of the Metropolitan Region of São Paulo: possible effects of global warming

• Grant number: 16/22264-8
• Support Opportunities: Research Program on Global Climate Change - Regular Grants
• Start date: March 01, 2017
• End date: February 28, 2019
• Field of knowledge: Engineering - Sanitary Engineering - Water Resources
• Principal Investigator: Ana Lúcia Brandimarte
• Grantee: Ana Lúcia Brandimarte
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Déborah Yara Alves Cursino dos Santos ; Marcelo Luiz Martins Pompêo

Abstract

In the Metropolitan Region of de São Paulo the water supply is largely dependent on areas located in Atlantic Forest, that are under high pressure due to urbanization in the surroundings. Global warming has the potential to make this situation worse because it could affect the availability and quality of water. In the case of tropical forests, these effects probably will be accompanied by savannization. In Brazil, this process means the replacement of natural forest by species from Cerrado, many of them having leaves heavily lignified that are hard to decompose. Detritus from terrestrial plant species are a crucial food source to detritivore aquatic fauna in low order streams of forest environments. Changes in detritus availability and quality due to the replacement of the plant cover have critical effects on the metabolism of those waterbodies. The increase of suspended fine particles could result from the uncompleted degradation of allochthonous detritus. This fact could increase the water turbidity, affecting supply water treatment processes. In this context, this research project aims to evaluate the breakdown of leaves of a common plant species from the transition zone between Cerrado e riparian forest in two streams: one in Cerrado and one in Atlantic Forest. Litter bags (leaf packs) will be put in the streams and collected after 7, 15, 30, 60 e 90 days. Breakdown of leaves and the diversity of detritivorous invertebrates in the litter bags will be estimated. Results will use to compare the streams regarding the velocity of leaf breakdown, patterns of colonization of leaves by biota, and diversity of detritivores fauna. Thus we intend to get information to anticipate if changes in operational procedures in supply water plants will be needed. (AU)