Effects of seasonality, trophic state and landscape properties on CO2 saturation in low-latitude lakes and reservoirs

Author(s):Show less -

Junger, Pedro Ciarlini ^{[1, 2]} ; Catombe Dantas, Fabiola da Costa ^[3] ; Guimaraes Nobre, Regina Lucia ^[3] ; Kosten, Sarian ^[4] ; Venticinque, Eduardo Martins ^[5] ; Araujo, Fernando de Carvalho ^[5] ; Sarmento, Hugo ^[1] ; Angelini, Ronaldo ^[6] ; Terra, Iage ^[3] ; Gaudencio, Andrievisk ^{[2, 7]} ; They, Ng Haig ^{[2, 8]} ; Becker, Vanessa ^[6] ; Cabral, Camila Rodrigues ^[3] ; Quesado, Leticia ^[3] ; Carneiro, Luciana Silva ^[5] ; Caliman, Adriano ^[5] ; Amado, Andre Megali ^{[9, 2]}

Affiliation

^[1] Univ Fed Sao Carlos, Dept Hidrobiol, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Rio Grande do Norte, Dept Oceanog & Limnol, BR-59014002 Natal, RN - Brazil

^[3] Univ Fed Rio Grande do Norte, Programa Posgrad Ecol, Natal, RN - Brazil

^[4] Radboud Univ Nijmegen, Inst Water & Wetland Res, Dept Aquat Ecol & Environm Biol, Heyendaalseweg 135, NL-6525 AF Nijmegen - Netherlands

^[5] Univ Fed Rio Grande do Norte, Dept Ecol, BR-59078900 Natal, RN - Brazil

^[6] Univ Fed Rio Grande do Norte, Dept Engn Civil, BR-59078970 Natal, RN - Brazil

^[7] Univ Fed Rio Grande do Norte, Programa Posgrad Engn Sanit & Ambiental, BR-59078970 Natal, RN - Brazil

^[8] Univ Fed Rio Grande do Sul, Ctr Estudos Costeiros Limnol & Marinhos CECLIMAR, Dept Interdisciplinar, BR-96625000 Porto Alegre, RS - Brazil

^[9] Univ Fed Juiz de Fora, Dept Biol, BR-36036900 Juiz De Fora, MG - Brazil

• Document type: Journal article
• Source: Science of The Total Environment; v. 664, p. 283-295, MAY 10 2019.
• Web of Science Citations: 1

Abstract

The role of tropical lakes and reservoirs in the global carbon cycle has received increasing attention in the past decade, but our understanding of its variability is still limited. The metabolism of tropical systems may differ profoundly from temperate systems due to the higher temperatures and wider variations in precipitation. Here, we investigated the spatial and temporal patterns of the variability in the partial pressure of carbon dioxide (pCO(2)) and its drivers in a set of 102 low-latitude lakes and reservoirs that encompass wide gradients of precipitation, productivity and landscape properties (lake area, perimeter-to-area ratio, catchment size, catchment area-to lake area ratio, and types of catchment land use). We used multiple regressions and structural equation modeling (SEM) to determine the direct and indirect effects of the main in-lake variables and landscape properties on the water pCO(2) variance. We found that these systems were mostly supersaturated with CO2 (92% spatially and 72% seasonally) regardless of their trophic status and landscape properties. The pCO(2) values (9-40,020 mu atm) were within the range found in tropical ecosystems, and higher (p < 0.005) than pCO(2) values recorded from high latitude ecosystems. Water volume had a negative effect on the trophic state (r = -0.63), which mediated a positive indirect effect on pCO(2) (r = 0.4), representing an important negative feedback in the context of climate change-driven reduction in precipitation. Our results demonstrated that precipitation drives the pCO(2) seasonal variability, with significantly higher pCO(2) during the rainy season (F = 16.67; p < 0.001), clue to two potential main mechanisms: (1) phytoplankton dilution and (2) increasing inputs of terrestrial CO2 from the catchment. We conclude that at low latitudes, precipitation is a major climatic driver of pCO(2) variability by influencing volume variations and linking lentic ecosystems to their catchments. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 17/26786-1 - Structuring processes of microbial communities and ecological networks in latitudinal gradients of the global ocean
• Grantee: Pedro Ciarlini Junger Soares
• Support Opportunities: Scholarships in Brazil - Doctorate