During the culture cycle, weekly water samples were taken directly
from the tanks (at 20–30 cm below the surface of the water) and the
output of pots (from recovery channels) (sampling time was between
12:00 and 13:00 h). One sample was filtered (Whatman GF/F) and
the unfiltered water samples were stored in clean plastic bottles
(120 mL) and transported at low temperature (4 °C) to the laboratory
after collection. Dissolved oxygen, temperature, salinity and pH were
measured in situ twice a day (6:00 and 18:00 h) with a dissolved oxygenmeter
(YSI model 58, USA) and a pH meter. Filtered water samples
were used to determine dissolved nutrients. The following analyses
were performed by procedures outlined in Grasshoff et al. (1990):
nitrite by the diazotization method, nitrate by a cadmium reduction
followed by diazotization, phosphate by the phosphomolybdenumprocedure,
and total ammonia by the phenate procedure. The groundwater
used in this trialwas analyzed in duplicate for major ionswith standard
techniques (APHA, 2012): chloride by an argentometric technique
using silver nitrate (method 4500 Cl− B), alkalinity by titration (method
2320 Alk B), calciumand magnesiumwere determined by flame atomic
absorption spectrophotometry (method 3500 Ca B; 3500 Mg B), and
potassium and sodium by flame emission spectrophotometry with an
air-acetylene flame (method 3500 K B; 3500 Na B).With the exception
of ammonia, for which the coefficient of variation was between 5 and
15%, the precision of these determinations was b10%. The estimated
During the culture cycle, weekly water samples were taken directly
from the tanks (at 20–30 cm below the surface of the water) and the
output of pots (from recovery channels) (sampling time was between
12:00 and 13:00 h). One sample was filtered (Whatman GF/F) and
the unfiltered water samples were stored in clean plastic bottles
(120 mL) and transported at low temperature (4 °C) to the laboratory
after collection. Dissolved oxygen, temperature, salinity and pH were
measured in situ twice a day (6:00 and 18:00 h) with a dissolved oxygenmeter
(YSI model 58, USA) and a pH meter. Filtered water samples
were used to determine dissolved nutrients. The following analyses
were performed by procedures outlined in Grasshoff et al. (1990):
nitrite by the diazotization method, nitrate by a cadmium reduction
followed by diazotization, phosphate by the phosphomolybdenumprocedure,
and total ammonia by the phenate procedure. The groundwater
used in this trialwas analyzed in duplicate for major ionswith standard
techniques (APHA, 2012): chloride by an argentometric technique
using silver nitrate (method 4500 Cl− B), alkalinity by titration (method
2320 Alk B), calciumand magnesiumwere determined by flame atomic
absorption spectrophotometry (method 3500 Ca B; 3500 Mg B), and
potassium and sodium by flame emission spectrophotometry with an
air-acetylene flame (method 3500 K B; 3500 Na B).With the exception
of ammonia, for which the coefficient of variation was between 5 and
15%, the precision of these determinations was b10%. The estimated
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