Post on 26-Nov-2018
A resposta da dinâmica sedimentar dos rios Xingu e Tapajós às mudanças climáticas e barragens de usinas
hidrelétricas: riscos para conservação da biodiversidade e produção de energia na Amazônia
Processo 2016/02656-9
Coordenador: André Oliveira Sawakuchi (IGc-USP)andreos@usp.br
The Xingu and Tapajós Rivers
Mazoca (2017)
Tapajós
Xingu
Photos: Leandro Sousa and Mark Sabaj
High diversity of lithophilic andrheophilic fishes
The largest tropical-rapidsecosystem
Hydropower dams in the Amazon
Latrubesse et al. (2017 – Nature)
São Luiz do Tapajós ~6,350 MWBelo Monte ~11,230 MW
Water balance projections (2070-2099) Xingu and Tapajós watersheds-35% Runoff
Sorribas et al. (2016 – Climatic Change)
Aquatic and flooding forest ecosystems
Changes in water column andsubstrates
Habitat loss and fragmentation
Fluvial system
Water balance Sedimentation/erosion dynamics
Climate and anthropogenic changes
Precipitation Hydropower dams
Approach: from past to present and future
Millenial tomultidecadalhydroclimate andlandscape changes
Variability of themodern system
Future scenarios
Middle and Late HoloceneLast 7,000 years
1970-2018
2018-2100
Results – Sept 2017 – Jun 2018 (Xingu)
Imagem: Juan Doblas (ISA)
Volta Grande do XinguUHE Belo Monte
Author: Marcelo Camargo (2016)
Millenial changes in hydroclimate
Xin
gu
Amazon
Sediment core
Bertassoli et al. (in prep.)
Precip in E Amazon (Wang et al., 2017 – Nature)
Water/sediment discharge
Decreasing water discharge since 2 kaMultidecadal abrupt changes in precip and water discharge
Slightly acid shallow water, lownutrients concentration (Staurosira,
Stauroneis, Staurosirella, Pinnularia, Gomphonema)
Years BP
Turbulent water(Aulacoseira)
Diatom analysisSamantha Borges (DR)Krysna Ferreira (MS)
Hydroclimate and landscapechanges
Flooding forest areas expanded after 5 kaHigh rate of expansion after 1 ka in the Xingu
OSL and 14C ages of flooding forest substrates in Amazon
Pupim et al. (in prep.)
10 km
Terra FirmeIgapó
Terra Firme
1.1±0.1 ka – present
Hydroclimate and vegetationchanges
Concentration (grains/cm3)
Core XC06
Pollen and charcoal analyses – Rudney Santos (DR)
Charcoal in sediments
Pollens and spores
• Cecropia, a successional forest indicator, is presentin expressive quantities, suggesting that the vegetation has not reached a climax stage since the Mid Holocene
• Mauritia flexuosa (Buriti palm) may be related to Late Holocene anthropogenic action
• Coarser charcoal particlessuggest increase of local firesduring the Late Holocene
Beach
River bed
Sites for P. expansa nesting (Tartaruga-da-Amazônia)
Pimental Dam
• Coarse sand (0.5-1.0 mm) is the major material for beach development• Sand sources are located upstream the dams• Upstream trapping of coarse sand reduce beach resilience
Luana Ferreira de Jesus (MS)
Projection: habitat loss (P. expansa)
After UHE Belo Monte
Lithophilic fish – Baryancistrus xanthellus
Magalhães et al. (in prep.)
• Average suspended sed rate at the Xingu ria = 0.35 cm/year(Bertassoli et al., 2017)
Population expansionstarted at 200 ka
Shift from bedrock to mudsubstrates (~80 km) in decadaltimescale
Carbon balance under the UHE Belo Monte
CO2 and CH4 sources
Flooded vegetation(forest and pasture)
Deposition of organicsediments
Rate of carbon accumulationFrom 84 g m-2 yr-1 to 169 g m-2 yr-1
TOC = 2-3%
• Higher production of CH4 and CO2 in flooded pasture soils
• Emissions concentrated in the first years after damming
Sawakuchi, H.O. et al. (in prep.)
The Xingu under future climate
Simulation of future waterdischarge at Belo Monte
Camargo et al. (in prep.)
• Higher frequency of droughts for the period 2017-2045 (CMIP5/IPCC, RCP 8.5 scenario);
• Future water discharge 28% lower than the observed during1990-2015
Camargo et al. (in prep.)
Monthly precip anomalies 2017-2045 (mm)
Present (1990-2015) and future (2017-204) water discharge (m3/s)
Energy generation: lower thanprojected?
Energy generation versus wateravailable for downstreamecosystems
Obrigado!
...Tapajós
Xingu...