Kerstin Töbe

Detection of zooplankton items in the stomach and gut content of larval krill, Euphausia superba, using a molecular approach

The usefulness of a molecular approach based on polymerase chain reaction (PCR) was investigated to identify and quantify the feeding of larval krill on zooplankton organisms in the Lazarev Sea during winter in 2006. Different primers and probes of dominant copepod species (Oithona sp., Ctenocalanus citer, copepodid stages of Metridia gerlachei and Calanoides acutus), co-occurring with larval krill under sea ice during winter, were developed for quantitative PCR (qPCR) and their species specificity was tested on target and non-target species. The qPCR results showed that larval krill were exclusively feeding on Oithona sp. This result was confirmed by microscopic analysis of stomach and gut contents of larvae from the same stations.

Seasonal occurrence at a Scottish PSP monitoring site of purportedly toxic bacteria originally isolated from the toxic dinoflagellate genus Alexandrium

There is increasing evidence that bacterial–algal interactions play a role in Harmful Algal Bloom (HAB) ecology. Bacteria that are associated with bloom-forming algal species, specifically toxic dinoflagellate algae, have been implicated in the production and biotransformation of paralytic shellfish toxins (PSTs). To clarify the role that these bacteria may play in the production of PSTs, it is desirable to identify and localize the bacteria associated with the dinoflagellates and enumerate them during the course of the algal blooms that the toxic dinoflagellates produce. Because 16S rRNA-targeted probes offer the possibility of both, we previously made and tested probes for some putatively toxigenic bacteria isolated from cultures of the PSP-related dinoflagellates Alexandrium tamarense, A. affine and A. lusitanicum. The bacteria isolated from the dinoflagellates belong primarily to the alpha-proteobacterial group of Roseobacter and the gamma-proteobacterial group of Alteromonas. Here, we report the succ...