Thalassiosira punctigera

Division: Bacillariophyta
Class: Coscinodiscophyceae
Order: Thalassiosirales
Species name: Thalassiosira punctigera Castr.
Synonyms: Thalassiosira angstii (Gran) MaKarova
Common name: A centric diatom
Date of introduction and origin
Thalassiosira punctigera was first detected in English waters (Plymouth, Devon) in 1978 (Wallentinus in press; G.R. Hasle pers. comm.). Its origin is unknown although it had only previously been recorded from the North Pacific and South Atlantic Oceans, plus one record from the Carribean (Hasle 1983).
Method of introduction
The method of introduction is unknown, but ballast transport cannot be ruled out and imported oysters have also been hypothesised as a potential vector (Rincé & Paulmier 1986; Wallentinus in press).
Reasons for success
Rate of spread and methods involved
It was reported from English waters and Helgoland in 1978; Norway in 1979; Netherlands in 1981 (Marine Biological Association 1979; Hasle 1990; Smayda 1990). Its method of spread is unknown.
It is found in the English Channel and North Sea (Wallentinus in press).
Factors likely to influence spread and distribution
Effects on the environment
Effects on commercial interests
Control methods used and effectiveness
None used.
Beneficial effects
None known.
It is an extremely variable species with regard to size and valve structure (Hasle 1983). It was very abundant in the English Channel in the period 1980-1981 but has subsequently been considered to have an insignificant role (Boalch 1987).
Boalch, G.T. 1987. Changes in the phytoplankton of the western English Channel in recent years. British Phycological Journal, 22: 225-235.
Hasle, G.R. 1983. Thalassiosira punctigera (Castr.) comb. nov., a widely distributed marine planktonic diatom. Nordic Journal of Botany, 3: 593-608.
Hasle, G.R. 1990. Diatoms of the Oslo fjord and the Skagerrak. Species new to the area: immigrants or overlooked in the past? Blyttia, 48:33-38.
Marine Biological Association. 1979. Report of the Council for 1971-1972. Journal of the Marine Biological Association of the United Kingdom, 52: 1067-1102.
Rincé, Y., & Paulmier, G. 1986. Donnée nouvelles sur la distribution de la diatomée marine Coscinodiscus wailesii Gran & Angst (Bacillariophyceae). Phycologia, 25: 73-79.
Smayda, T.J. 1990. Novel and nuisance phytoplankton blooms in the sea: evidence for a global epidemic. In: Toxic marine phytoplankton, Granéli, E, Sundström, B., Elder, L., & Anderson, D.M. eds. Proceedings of the Fourth International Conference on Toxic Marine Phytoplankton, 26-30 June 1989, Lund, Sweden. Elsevier, New York, p29-40.
Wallentinus, I. In press. Status of introductions of non-indigenous marine species to north Atlantic waters: introductions and transfers of plants. ICES co-operative research report.
Acknowledgements (contributors)
Prof. G.R. Hasle, University of Oslo.