Effects of small-scale turbulence on two species of Dinophysis

Publication date: November 2019Source: Harmful Algae, Volume 89Author(s): María García-Portela, Beatriz Reguera, Maurizio Ribera d’Alcalà, Francisco Rodríguez, Marina MontresorAbstractDinoflagellate species of Dinophysis, in particular D. acuminata and D. acuta, produce lipophilic toxins that pose a threat to human health when concentrated in shellfish and jeopardize shellfish exploitations in western Europe. In northwestern Iberia, D. acuminata has a long growing season, from spring to early autumn, and populations develop as soon as shallow stratification forms when the upwelling season begins. In contrast, D. acuta blooms in late summer, when the depth of the pycnocline is maximal and upwelling pulses are moderate. In situ observations on the hydrodynamic regimes during the two windows of opportunity for Dinophysis species led us to hypothesize that D. acuta should be more sensitive to turbulence than D. acuminata.To test this hypothesis, we studied the response of D. acuminata and D. acuta to three realistic turbulence levels low (LT), ε ≈ 10−6 m2 s-3; medium (MT), ε ≈ 10-5  m2 s-3 and high (HT), ε ≈ 10-4 m2 s-3 generated by Turbogen, a highly reproducible, computer-controlled system. Cells of both species exposed to LT and MT grew at rates similar to the controls. Marked differences were found in the response to HT: D. acuminata grew slowly after an initial lag phase, whereas D. acuta cell numbers declined. Results from this study support the hypot...
Source: Harmful Algae - Category: Environmental Health Source Type: research