RT journal article
T1 Dissolved CH4 coupled to photosynthetic picoeukaryotes in oxic waters and to cumulative chlorophyll a in anoxic waters of reservoirs
A1 León-Palmero, Elizabeth
A1 Contreras-Ruiz, Alba
A1 Sierra Padilla, Ana
A1 Morales-Baquero, Rafael
A1 Reche, Isabel
A2 Química Física
AB Methane (CH4) emissions from reservoirs are responsible for most of the atmospheric climatic forcing of these aquatic ecosystems, comparable to emissions from paddies or biomass burning. Primarily, CH4 is produced during the anaerobic mineralization of organic carbon in anoxic sediments by methanogenic archaea. However, the origin of the recurrent and ubiquitous CH4 supersaturation in oxic waters (i.e., the methane paradox) is still controversial. Here, we determined the dissolved CH4 concentration in the water column of 12 reservoirs during summer stratification and winter mixing to explore CH4 sources in oxic waters. Reservoir sizes ranged from 1.18 to 26.13 km(2). We found that dissolved CH4 in the water column varied by up to 4 orders of magnitude (0.02-213.64 mu mol L-1), and all oxic depths were consistently supersaturated in both periods. Phytoplanktonic sources appear to determine the concentration of CH4 in these reservoirs primarily. In anoxic waters, the depth-cumulative chlorophyll a concentration, a proxy for the phytoplanktonic biomass exported to sediments, was correlated to CH4 concentration. In oxic waters, the photosynthetic picoeukaryotes' abundance was significantly correlated to the dissolved CH4 concentration during both the stratification and the mixing. The mean depth of the reservoirs, as a surrogate of the vertical CH4 transport from sediment to the oxic waters, also contributed notably to the CH4 concentration in oxic waters. Our findings suggest that photosynthetic picoeukaryotes can play a significant role in determining CH4 concentration in oxic waters, although their role as CH4 sources to explain the methane paradox has been poorly explored.
PB COPERNICUS GESELLSCHAFT MBH
SN 1726-4170
YR 2020
FD 2020-06
LK http://hdl.handle.net/10498/23404
UL http://hdl.handle.net/10498/23404
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 11-nov-2026