Primary production of phytoplankton and periphyton in two humic lakes of a South American wetland

RODRÍGUEZ, PATRICIA; VERA, M. SOLANGE; PIZARRO, HAYDÉE

LIMNOLOGY

SPRINGER TOKYO

Lugar: Tokyo; Año: 2012 vol. 13 p. 281 - 287

1439-8621

Seasonal primary productivities of periphytonand phytoplankton were compared in Grande Lake (GL) anda relict oxbow lake (ROL) in winter 2006 and summer 2007.GL was free of floating plants on the sampling dates andcovered over 80 and 100% of the ROL surface in winter andsummer, respectively. The 14C assimilation technique wasused to obtain the P?E curves of phytoplankton and periphytonon artificial substrata. The periphytic maximum photosyntheticrate (Pmax) was higher in the ROL in winter andsummer, being better adapted to low irradiances than those inthe GL. Phytoplankton and periphytic algae were light-limitedin the ROL in summer due to complete coverage byfloating macrophytes. In summer, Pmax and a values forperiphyton in the ROL were higher than those for phytoplankton,and were even higher than in GL. In turn,Pmax and avalues for phytoplankton in Grande Lake were higher thanthose for periphyton due to improved light conditions and thepresence of algae that were adapted to movement through thewater column. These results suggest that the complete coverageby floating macrophytes restricted phytoplankton productivityand allowed the development of a periphyticcommunity that was better adapted to low-light conditions.