In the 300-l tanks, the yield of the Gracilaria that
received water from Chondrus was not significantly
different than that receiving water from Gracilaria
(pN0.05). In terms of the biofiltration performance
(Fig. 2), in the 1500-l tanks Gracilaria had a higher
efficiency of TAN uptake, as compared to Chondrus,
75.4% (±7.07%) vs. 41.3% (± 17.32%), respectively. In
the cascade system, these differences were compensated
by the Gracilaria culture in the 300-l tanks, i.e., by the
second level of the cascade system. For this reason, the
nitrogen uptake efficiency of the two cascade systems
was similar: 83.5% (± 6.47%) for the Gracilaria
+Gracilaria system and 80.5% (± 7.50%) for the Chondrus+Gracilaria
system (Fig. 2). When the NUE of
Gracilaria cultures growing in the 300-l tanks were
analyzed separately, those that received water from
Chondrus cultures were more than twice as efficient
than those receiving water from Gracilaria (Fig. 2).