The dynamics of Chrysochromulina species in the Skagerrak in relation to environmental conditions

Environmental forcing as a main determinant of bloom dynamics of theChrysochromulinaalgae

“…Nutrient levels and ratios, as represented by PCA1 and PCA2, were indicated to be of prime importance for the Chrysochromulina blooms. This supports the hypotheses forwarded soon after the extreme bloom of C. polylepis in 1988 (Aksnes et al 1989;Dahl et al 1989;Maestrini & Granéli 1991), as well as the results from the more preliminary evaluation of a subset of the same data as analysed in depth in the present paper (see Dahl et al 2005). In addition to the effect of the nutrient status of the system, our present study shows that the flux of North Seawater into the Skagerrak (simulated inflow data), as well as alongshore northeasterly wind stress (setting up shoreward water transport) play important roles in the Chrysochromulina concentration at our coastal sampling station.…”

“…Profiles of temperature and salinity from the surface to 75 m are recorded by a Neil Brown CTD , while water samples for analysing nutrients and chlorophyll a are sampled at standard depths (0, 5, 10, 20, 30, 50, 75 m). The chemical analyses are performed according to standard procedures (see Dahl et al 2005).…”

Nitrogen processes in coastal and marine ecosystems

“…Th ere are associated 'foam events' (Lancelot, 1995 ) and, the toxin-producer Chrysochromulina spp . blooming between April and August in the Kattegat and Skagerrak off the coasts of Denmark, Sweden and Norway (Dahl et al ., 2005 ). Th e toxicity of Chrysochromulina varies however between species and within the same species, under control of environmental conditions (Johansson and Graneli, 1999 ).…”

“…Th e toxicity of Chrysochromulina varies however between species and within the same species, under control of environmental conditions (Johansson and Graneli, 1999 ). Extensive blooms of harmful C. polylepis were up to now only recorded in May-June 1988 when they decimated farmed fi sh (Dahl et al ., 2005 ).…”

Genomic characterisation of the ichthyotoxic prymnesiophyteChrysochromulina polylepis,and the expression of polyketide synthase genes in synchronized cultures

“…The genus Chrysochromulina has close morphological and molecular phylogenetic relationships with the ichthyotoxic prymnesiophycean Prymnesium and shares the capacity to form HABs in coastal and brackish waters (reviewed in Edvardsen, 1996). Although several of over 50 described Chrysochromulina species are reported to be potentially toxic, most attention has been focussed on C. polylepis Manton et Parke, the source of a devastating toxic bloom that occurred in the Kattegat and Skagerrak region near the Norwegian coast in the late 1980s (Dahl et al, 1989(Dahl et al, , 2005Grane´li et al, 1993). This bloom resulted in extensive fish kills and caused severe ecological damage to wild biota with high economic losses at fish farms along the Norwegian and Swedish coasts (Nielsen et al, 1990;Skjoldal & Dundas, 1991;Gjøsaeter et al, 2000).…”