TITLE:
Carbon Burial in Young Tropical Reservoirs Is Higher at Lower Latitudes*
AUTHORS:
Elizabeth Sikar, Marco Aurelio dos Santos, Ana Carolina Moterani, Isabella Matvienko, Ana Carla Martins Veras, Juliana Pinto Pereira Dias, Orleno Marques da Silva Junior, Claudio Pavani, Marcelo Amorim, Teodosio das Neves Milisse Nzualo, Ayr Manoel Portilho Bentes Junior, Rogerio Duarte
KEYWORDS:
Carbon, Burial, Sediments, Hydroelectric Reservoirs
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.9 No.12,
December
28,
2021
ABSTRACT: Man-made environments such as tropical hydroelectric reservoirs alter the
preexisting carbon (C) cycle and remove C from circulation through burial in
sediments. Carbon burial (CB) was measured using the silica-tracer method
during four field surveys in the less than six-year-old Belo Monte tropical
reservoir. Fresh C sedimentation was also measured. Belo Monte’s CB median rate
276 (n = 84; min 0; max 352,625 mg C·m-2·d-1) is within
the range (230 to 436 mg C·m-2·d-1) of CB rates measured
further downstream at the Xingu Ria and higher than the averaged over 50 years
oceanic rate 244 mg C·m-2·d-1 estimated for an
increasingly deoxygenated ocean. Carbon burial median rates of tropical
reservoirs with similar age and trophic state correlate inversely with latitude
at a rate of 17.5 mg C·m-2·d-1 per degree. Carbon burial
efficiency of these reservoirs correlates positively with latitude at a ratio
of 0.22% per degree.