Diversity and seasonality of Pseudo-nitzschia (Peragallo) at two North Sea time-series monitoring sites

Abstract

Species within the diatom genus Pseudo-nitzschia (Peragallo) have been identified as producers of domoic acid, the toxin responsible for amnesic shellfish poisoning. Toxin-and non-toxin-producing species of Pseudo-nitzschia have been reported globally; however, as Pseudo-nitzschia species cannot be routinely identified to species level using light microscopy, cells are rarely recorded to species level during long-term monitoring studies. Here, we report the results of a comparative survey of Pseudo-nitzschia species at two monitoring sites in the North Sea: Stonehaven on the east coast of Scotland and Helgoland Roads in the German Bight. A difference in the seasonality of this genus was observed between the sites with Pseudo-nitzschia cells playing a major role in the spring bloom as well at the summer and autumn diatom community at Stonehaven. In contrast, Pseudo-nitzschia was abundant only during the summer months at Helgoland. Pseudo-nitzschia cells constitute a higher proportion of the diatom community at Stonehaven than at Helgoland, particularly during the late summer, autumn and winter and thus may be considered more 'ecologically important' at this site. A total of eight different species were recorded during this survey with five Pseudo-nitzschia species observed at the Helgoland site: P. pungens, P. fraudulenta, P. americana, P. cf. delicatissima and the potentially toxic species P. multiseries. Six species were also recorded at Stonehaven; P. australis, P cf. delicatissima, P. pungens, P. cf. pseudodelicatissima, P. subpacifica and P. seriata. This study represents the first examination of the seasonality of Pseudo-nitzschia species around Helgoland and the first comparison between two long-term monitoring sites in the North Sea. P. americana and P. multiseries are also recorded at the Helgoland Roads time-series site for the first time.

Two decades of Pseudo-nitzschia spp. blooms and king scallop (Pecten maximus) contamination by domoic acid along the French Atlantic and English Channel coasts: Seasonal dynamics, spatial heterogeneity and interannual variability

“…These results were congruent with previous studies reporting PSN blooms in spring and at the end of the summer in very diverse ecosystems such as the Gulf of Mexico (Dortch et al, 1997;Parsons and Dortch, 2002;Parsons et al, 2013), western Scottish waters (Fehling et al, 2006), the North Sea (Bresnan et al, 2015) or the Mediterranean Sea (Mercado et al, 2005).…”

“…8).These results suggest recurring local events to be at play in stimulating toxic PSN blooms every year in the Northern Bay of Biscay. The coincidence of PSN dominance and ASP events has been shown in the North Sea (Bresnan et al 2015). Indeed, the Scottish site where diatom cell abundance was dominated by the PSN was affected by toxicity, whereas in German sites, where diatom blooms were not dominated by PSN no toxic events have been observed.…”

“…six species have been identified in the Seine bay over an entire year (Klein et al, 2010). In Stonehaven (Scotland), Bresnan et al (2015) showed that, P. australis and P. seriata, which are highly toxic, were only observed in late summer and autumn whereas in spring P.…”

Pseudo-nitzschia sp. diversity and seasonality in the southern North Sea, domoic acid levels and associated phytoplankton communities

“…In the Eastern English Channel-North Sea (EEC-NS), reported ASP events were mainly concentrated in the northern regions (Scotland, Norway, Denmark;Trainer et al, 2012) although Pseudo-nitzschia sp. cells are present year-round in the southern regions (Bresnan et al, 2015;Hernández-Fariñas et al, 2014;Schapira et al, 2008;Seuront et al, 2006). Thus, reports of DA and shellfish closures were not recorded in the EEC-NS until 2014, when king scallop stocks off the Bay of Somme (France) were contaminated with DA, which represented the northernmost ASP alert of France (Lefebvre A., pers.…”

Phylogenetic relationships of Pseudo-nitzschia subpacifica (Bacillariophyceae) from the Mexican Pacific, and its production of domoic acid in culture

“…Pseudo-nitzschia subpacifica was originally described in Hasle [32] as Nitzschia subpacifica. It has been documented in Angola, Australia [33], Korea [34], China [35], Greece [36], Hong Kong [23], Peru [37] and Scotland coasts, [38] but has not been reported in the Mexican Pacific. DA production has been documented in only one strain isolated from Gulf of Maine [39].…”