Seawater Exchange
When culturing nori in flowthrough tank systems, seawater exchange rates must be determined in order to
ensure proper removal of waste metabolites and delivery of required nutrients. Flushing rates must equal or exceed
the rate at which phytoplankton (microscopic photosynthetic algae) contamination, waste metabolites,
and algal debris accumulates in the tanks (Craigie & Shacklock, 1995). Tank systems for growing red seaweeds
typically have water exchange rates between 3 and 7 tank volumes per week (Craigie & Shacklock, 1995). Water
exchange can also be an important mechanism for temperature control and the addition of certain nutrients
such as carbon through the bubbling of CO2
. Systems can be set up to
be fully automatic and respond to parameters such as temperature, irradiance,
and pH (Bidwell et al. 1985).