Every day, in vivo chlorophyll-a fl

Every day, in vivo chlorophyll-a fluorescence was
measured using a Trilogy fluorometer (Turner Designs) and 6 mL of culture
were sampled, fixed with lugol:glutaraldehyde (2% final
concentration, Verity et al., 2007) and stored in the dark in a cold room
(4 °C) for P. delicatissima microscopic cells enumeration (Utermöhl
method, ×200, ×400). Over its growth cycle, P. delicatissima abundance
was significantly related to in vivo fluorescence following
the equation (Eq. 1): A = 27,041.7 × F (Eq. 1, n = 34, R2 = 0.99,
p b 0.01), where A is P. delicatissima abundance (cells mL−1),
and F is the corresponding in vivo fluorescence (RFU). To assess
whether the considered P. delicatissima strain produced domoic
acid (particulate and dissolved), 5 mL of culture were daily sampled
and frozen (−20 °C) until analysis with ASP ELISA kits (Biosense
Laboratories, Bergen, Norway).