Journal Article
Effects of Water Table Fluctuation on Greenhouse Gas Emissions from Wetland Soils in the Peruvian Amazon
Jaan Pärn; Kaido Soosaar; Thomas Schindler; Katerina Machacova; Waldemar Alegría Muñoz; Lizardo Fachín; José Luis Jibaja Aspajo; Robinson I. Negron-Juarez; Martin Maddison; Jhon Rengifo; Danika Journeth Garay Dinis; Adriana Gabriela Arista Oversluijs; Manuel Calixto Ávila Fucos; Rafael Chávez Vásquez; Ronald Huaje Wampuch; Edgar Peas García; Kristina Sohar; Segundo Cordova Horna; Tedi Pacheco Gómez; Jose David Urquiza Muñoz; Rodil Tello Espinoza; Ülo Mander
Wetlands · Vol. 43, Issue 6 · 2023
Abstract
Amazonian swamp forests remove large amounts of carbon dioxide (CO 2 ) but produce methane (CH 4 ). Both are important greenhouse gases (GHG). Drought and cultivation cut the CH 4 emissions but may release CO 2 . Varying oxygen content in nitrogen-rich soil produces nitrous oxide (N 2 O), which is the third most important GHG. Despite the potentially tremendous changes, GHG emissions from wetland soils under different land uses and environmental conditions have rarely been compared in the Amazon. We measured environmental characteristics, and CO 2 , CH 4 and N 2 O emissions from the soil surface with manual opaque chambers in three sites near Iquitos, Peru from September 2019 to March 2020: a pristine peat swamp forest, a young forest and a slash-and-burn manioc field. The manioc field showed moderate soil respiration and N 2 O emission. The peat swamp forests under slight water table drawdown emitted large amounts of CO 2 and CH 4 . A heavy post-drought shower created a hot moment of N 2 O in the pristine swamp forest, likely produced by nitrifiers. All in all, even small changes in soil moisture can create hot moments of GHG emissions from Amazonian wetland soils, and should therefore be carefully monitored.