TITLE:
Emergent Macrophytes Alter the Sediment Composition in a Small, Shallow Subtropical Lake: Implications for Methane Emission
AUTHORS:
Claudio Cardoso Marinho, Cleber Palma-Silva, Edélti Faria Albertoni, Iara Bueno Giacomini, Marcos Paulo Figueiredo Barros, Leonardo Marques Furlanetto, Francisco de Assis Esteves
KEYWORDS:
Methane Emission, Shallow Lakes, Greenhouse Gases, Global Warming
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.6 No.2,
February
10,
2015
ABSTRACT: Aquatic macrophytes in shallow lakes emit high levels of methane. We hypothesize that the presence of emergent aquatic macrophytes in an artificial shallow lake promotes important input of autochthonous organic matter (OM) in sediment and higher levels of methane emission via bubbles. Samplings were performed at three sites in a small, shallow subtropical lake: (1) one station in the limnetic region and (2) - (3) two stations in the littoral region ((2) inside and (3) outside aquatic macrophyte stands). A higher concentration of OM was observed at the macrophyte station, and within this site, a higher methane concentration was observed in the sediment. These results could explain the methane ebullition values at macrophyte sites. At the macrophyte station, methane emission via bubbles contributed 17% to 56% of the total methane emission; however, at the other stations, its contribution via bubbles, was lower than 1%. This research confirmed the importance of emergent macrophytes at Polegar Lake as a source of OM in sediment and methane emission via bubbles. Further, we could confirm the positive effects of temperature on methane emission, mainly by bubbles.