Driving factors of the potentially toxic and harmful species of Prorocentrum Ehrenberg in a semi-enclosed Mediterranean lagoon (Tunisia, SW Mediterranean)

Abstract

We analysed the dynamics of the potentially toxic and harmful species of Prorocentrum Ehrenberg in Bizerte Lagoon (important aquaculture area, Northern Tunisia), substantiating the possible driving forces (temperature, salinity and nutrients), based on a two-year database. We revealed that Prorocentrum spp. blooms of high magnitude (10 4 -10 5 cells l -1 ) occurred mostly during the period of late winter to early spring. We found five species of Prorocentrum, two of which, namely P. lima and P. cordatum, the most common during the field, are confirmed agents of Diarrhetic Shellfish Poisoning in various regions of the world. Prorocentrum sp., P. micans and P. gracile were however present only sporadically but with high cell abundances, exemplifying bloom densities. Canonical correspondence analysis revealed that P. minimum and P. lima were much more abundant in eutrophic waters characterized by high Chl a biomass, while P. gracile species occurred principally in warm waters. Furthermore, Prorocentrum sp. and P. micans seemed more likely to proliferate in saline waters with high concentrations of inorganic nutrients (nitrate, ammonia and phosphate). Our study calls attention to a possible intensification of DSP events in Bizerte Lagoon, given the propensity of Prorocentrum spp. to proliferate in a eutrophic system.

Morphometric characterization of Dinophysis acuminata/D. sacculus complex in Guanabara Bay, Brazil

“…Reguera et al 2012, Hattenrath-Lehmann et al 2015, as well as the occurrence of a bloom of Prorocentrum after Dinophysis events (Campbell et al 2010). Prorocentrum micans, which reached densities as high as 10 6 cells L -1 in the present work, was reported as highly abundant in warm and nutrient-rich waters, such as that of GB (Sahraoui et al 2013). Prorocentrum micans was also reported as a producer of putative palytoxin and ovatoxin-a (Ignatiades & Gotsis-Skretas 2010), nevertheless, the frequent association of this species with DSP could be due to the presence of D. acuminata in densities too low to be detected (Reguera et al 2014 and references therein).…”

Toxicity and Growth Assessments of Three Thermophilic Benthic Dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) Developing in the Southern Mediterranean Basin

“…episodes [125]. P. lima represents a significant part of the seawater microphytoplanktonic community of the Bizerte Lagoon, reaching concentrations higher than 10 4 cell·L −1 [69]. No published data are available for the Bizerte Bay.…”

“…Nevertheless, more research on toxic strains is needed, particularly in the Southern Mediterranean basin. Reports about the occurrence of these species along the southern coasts are limited to Tunisia [66,67,68,69,70,71,72,73], Egypt [74,75] and Algeria [76]. These studies were based only on fixed field samples.…”

Morfologija i ekologija slabo poznatog dinoflagelata Prorocentrum arcuatum (Dinophyceae) iz Medulinskog zaljeva (istočni dio Jadranskog mora)

“…Presumably, temperature and salinity are major factors controlling the increased abundance of P. arcuatum (MUNIR et al, 2013;SAHRAOUI et al, 2013). Based on our results from Medulin Bay and the results from Lake Rogoznica (BARIĆ et al, 2003;BURIĆ et al, 2009), the optimum physical conditions for P. arcuatum proliferations in the water column seem to be the temperature of about 20°C, and salinity of at least 37.…”