Abstract
The light-dark bottle method and benthic chamber method were used to estimate the gross photosynthetic rate of benthic tidal microalgae. In the light-dark bottle method, 0.5g of wet bottom sediment and an incubation time of 6 hours were employed for the measurement of the photosynthetic rate of the benthic microalgae. The gross primary production of the benthic microalgae at the in situ temperature and photon flux density, determined by the light-dark bottle method, reached 2.1 gC · m-2 · day-1 on October 7, 2003 at the experimental tidal flat in Hannan Second District, Osaka Bay. The gross photosynthetic rate per unit chlorophyll a concentration of the benthic microalgae increased with increasing photon flux density in the benthic chamber. Using the present benthic chamber method, together with the in situ photon flux density and chlorophyll a concentration of the bottom sediment, the gross production of the benthic microalgae was estimated to be an average of 0.34gC · m-2 · day-1 at the Wakagawa tidal flat on October 3, 2005.
