The internet is well suited to provide and communicate taxonomic information for biodiversity-specialists and users. We are exploring the feasibility of a communal resource for marine phytoplankton biodiversity and working out a strategy for sustainability. The AWI has considerable data on phytoplankton species of the North Sea as a result of two time-series involving Helgoland (1966 to 1971 and 2001-present) and Sylt (since 1987). In collaboration with the Marine Biological Laboratory of Woods Hole, the Station Biologique Roscoff and IOC Centre, University of Copenhagen, several other sites with information on phytoplankton and potentially toxic algae are being established. These sites are collectively referred to as plankton*net and will share their contents by using a distributed-workgroup-environment. Plankton*net uses the TNS system of the uBio project (http://www.ubio.org) to organize and index information on organisms and to make taxon-specific links between sites. Plankton*net will promote a distributed but communal resource carrying key information about marine phytoplankton. It will publicise taxonomic data from the AWI, in addition it could be used to attach meta-information, and serves as a model for a European/international networking. The system is useful to be associated with matrix identification guides.http://e-bck.rd.awi-bremerhaven.de/protist/baypaul/microscope/general/page_01.htm