PHOTOSYNTHETHIC PARAMETER ASSESSMENT OF CORAL ZOOXANTHELLAE OF Acropora aspera AND Favites abdita USING MAXI I-PAM SYSTEM IN HERON ISLAND, GREAT BARRIER REEF, AUSTRALIA

Abstract

Zooxanthellae, which reside inside the coral host, have been an essential component in coral ecosystem studies. While residing inside their host, zooxanthellae photosynthesize provide energy and nutrients to coral. Objectives are to observe the impact of increasing light treatment to the coral by studying correlation between photosynthetic parameters and the cell condition of zooxanthellae. Materials used for this research were coral samples of Acropora aspera and Favites abdita, acquired from shallow waters (<2m) in the lagoons of Heron Island, Australia. This research was conducted from the first until the ninth of August 2005. Sample analysis was conducted in Director’s Laboratory at Heron Island Research Station (HIRS),Queensland University, Australia. Samples were obtained with Stratified Random Sampling method. Zooxanthellae parameters measured were cell size, cell density, and chlorophyll concentration per cell. Photosynthetic parameters measured from coral samples were values of Effective PSII Quantum Yield (Y(II)) and Non- Photochemical Quenching (NPQ/4) by using MAXI-Imaging-Pulsed AmplitudeModulation (I-PAM) System with PAR treatments ranging from 0 to 1251 μmol quanta m-2 s-1. I-PAM data were measured using ImagingWin version 1.01 software (Heinz Walz GmbH, Germany), graphs and charts analysis were used to observe the correlation between zooxanthellae and photosynthetic parameters. Results for three colonies of A. aspera and F. abdita had shown fluctuation tendency in Y (II) and NPQ/4 values is a decrement of Y(II) values parallel with the increment of NPQ/4 values; a similar condition was also observed in inter-species comparison. Three colonies of A. aspera show that the value of cell density tends to be proportional to the Y(II) value resistance and NPQ/4 value attainment. Similar results, with the exception of PAR limit reaching 461 μmol quanta m-2 s-1, was also occurred in three colonies of F. abdita. During treatments from 0 until 1251 μmol quanta m-2 s-1 PAR, a two species comparison of A. aspera and F. abdita show that Y(II) value resistance and NPQ/4 value attainment in A. aspera tends to be lower than F. abdita; which was proportional to the increase of cell size and also chlorophyll concentration of zooxanthellae.