抄録
The potential of the red alga Gracilaria bursa-pastoris
as a potential biofilter component was tested in an integrated multi-trophic
aquaculture systems (IMTA). Nutrient uptake characteristics of the species
in media with inorganic nitrogen showed inhibition of uptake of nitrate by
ammonium based on significant differences between their mean uptake rates
(19.26 μmol g dry wt-1 h-1 for nitrate and 66.11 μmol
g dry wt-1 h-1 for ammonium) and oscillations in their
substrate concentrations within the 48-h incubation period. With the red sea
bream (Pagrus major) effluent water, G. bursa-pastoris
reduced 35.63 ± 11.10 %, 29.14 ± 19.65 % and 55.67 ± 13.80 % for
nitrate, phosphate and ammonium, respectively. Mean uptake rate for ammonium
(758.35 ± 378.65 μmol kg wet wt-1 h-1) in the effluent
water was higher compared to nitrate and phosphate and supported high growth
rates (11.70 % d-1) and N:P ratio (19.64). Dark uptake of
nutrients and suppression of ammonium over nitrate was observed in both
inorganic N media and fish effluents.
This study shows that G. bursa-pastoris is an efficient
biofilter based on its affinity for ammonium, capacity for dark uptake and
high growth rate in fish effluents. The biomass obtained can provide
additional revenue through its use as human food, source of agar and as feed
for abalone.
