Premium
Carbon Dioxide Fluxes to the Atmosphere From Waters Within Flooded Forests in the Amazon Basin
Author(s) -
Amaral Joao Henrique Fernandes,
Melack John M.,
Barbosa Pedro Maia,
MacIntyre Sally,
Kasper Daniele,
Cortés Alicia,
Silva Thiago Sanna Freire,
Nunes de Sousa Rodrigo,
Forsberg Bruce R.
Publication year - 2020
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005293
Subject(s) - environmental science , carbon dioxide , hydrology (agriculture) , atmosphere (unit) , flux (metallurgy) , subtropics , carbon cycle , atmospheric sciences , surface water , dissolved organic carbon , amazon rainforest , diel vertical migration , environmental chemistry , ecosystem , chemistry , ecology , oceanography , geology , geography , geotechnical engineering , organic chemistry , environmental engineering , meteorology , biology
Inundated tropical forests are underrepresented in analyses of the global carbon cycle and constitute 80% of the surface area of aquatic environments in the lowland Amazon basin. Diel variations in CO 2 concentrations and exchanges with the atmosphere were investigated from August 2014 to September 2016 in two flooded forests sites with different wind exposure within the central Amazon floodplain (3°23′S, 60°18′W). CO 2 profiles and estimates of air–water gas exchange were combined with ancillary environmental measurements. Surface CO 2 concentrations ranged from 19 to 329 μM, CO 2 fluxes ranged from −0.8 to 55 mmol m −2 hr −1 and gas transfer velocities ranged from 0.2 to 17 cm hr −1 . CO 2 concentrations and fluxes were highest during the high water period. CO 2 fluxes were three times higher at a site with more wind exposure (WE) compared to one with less exposure (WP). Emissions were higher at the WP site during the day, whereas they were higher at night at the WE site due to vertical mixing. CO 2 concentrations and fluxes were lower at the W P site following an extended period of exceptionally low water. The CO 2 flux from the water in the flooded forest was about half of the net primary production of the forest estimated from the literature. Mean daily fluxes measured in our study (182 ± 247 mmol m −2 d −1 ) are higher than or similar to the few other measurements in waters within tropical and subtropical flooded forests and highlight the importance of flooded forests in carbon budgets.