Apart from increasing toxin produc- tion in already toxic species/strains, presence of grazers may even induce toxin production in species previously considered non-toxic, as shown for P. obtusa 3. It is therefore relevant to consider that all Pseudo-nitzschia spe- cies might have the potential to pro- duce DA, given the appropriate trigger- ing conditions. The results mentioned above illustrate the importance of con- sidering different chemical, physical as well as biological factors when predict- ing and modelling toxicity of Pseudo- nitzschia in the field. ture and that these cells may end up as being non-toxic (see refs in 1). This decrease in toxin content over time has been related to a simultaneous decrease in cell size 4, as Pseudo-nitzschia cells, like other vegetative cells of diatoms, decrease in cell size with time and thus contain less toxin per cell. This hypothe- sis has been supported by observations of P. cuspidata of which some (but not all) of the large cells after sexual repro- duction are more toxic than the smaller parent cells 5. Another explanation for the decrease in toxin content over time is related to bacteria. A correlation between decreases in Pseudo-nitzschia toxin content and simultaneous chang- es over time in bacterial communities in Pseudo-nitzschia cultures has been hy- pothesized. Because some bacteria have been shown to promote DA production whereas others degrade DA, changes in bacterial communities might poten- tially be an explanation 6. Changes in bacterial communities over time have been observed in some studies, but not others 7, 8. In recent studies on interactions be- tween copepods and Pseudo-nitzschia, grazing copepods (like Calanus species) have been shown to trigger an increase in toxin production 3, 9-11. We hy- pothesize that the reason for a decrease in DA production over time in labora- tory cultures might be related to a lack of grazers in laboratory cultures. When exposed to grazing copepods, toxin pro- duction has been shown to increase up 6 to 130 times, depending on exposure time (12 hours to 10 days) as well as concentration and species of copepod (Table 1, 2-5). One can easily imagine that the lack of such a potent toxin- trigger will have an effect. When estab- lishing clonal cultures in the laboratory, single cells are removed from the natu- ral environment and kept in pure cul- tures without exposure to grazers. The lack of the triggering factor that grazers exercise thus results in a continuous de- crease in toxin production. Toxin-inducing factors A lack of copepod grazers may also ex- plain why field data on cellular toxin content shows higher toxin levels than laboratory cultures of the same spe- cies from the same area 5. But several other factors also influence production of DA. A preliminary comparison of some of the factors affecting DA pro- duction shows that toxin production may increase more than 100 times due to copepod grazing or depletion of phosphate and silicate, whereas pres- ence of bacteria, salinity increase or pH increase showed a smaller degree of induction (See Table 1). This is not an exhaustive comparison and does not include the rate of toxin induction as the time of incubation was not avail- able for many of the experiments, but may nonetheless give an indication of the importance of some of the factors affecting DA-production. References: 1. Lundholm 2017. Diatoms. In http:// www.marinespecies.org/hab/ 2. Lelong A et al 2012. Phycologia 51: 168- 216 3. Harðardóttir et al 2015. Mar Drugs 13: 3809-3835 4. Mafra LL Jr et al 2009. Aquat Biol 6: 201212 5. Lundholm N et al 2012. J Phycol 48: 436- 454 6. Stewart JE 2008. Aquat Microb Ecol 50: 135-144 7. Sapp et al 2007. Microb Ecol 53: 683-699 8. Guannel ML et al 2011. Aquat Biol 64: 117-133 9. Tammilehto A et al 2015. Aquat Toxicol 159: 52-61 10. Leandro LF et al 2010. J Exp Mar Biol Ecol 382: 88-95 11. Miesner A K et al 2016. J Plankton Res 38: 564-574 12. Sun J et al 2011. Limnol Oceanogr 56: 829-840 13. Trimborn S et al 2008. Physiol Plant 133: 92-105 14. Fehling J et al 2004. J Phycol 40: 622- 630 15. Pan YL et al 1996. Mar Ecol Prog Ser 131: 225-233 16. Pan YL et al 1996. Mar Ecol Prog Ser 13: 235-243 17. Lewis NI 1993. In: Smayda TJ & Y Shimi- zu (eds) Toxic Phytoplankton Blooms in the Sea. Elsevier Science Publishers pp 601-606 18. Doucette GJ et al 2009. Harmful Algae 8: 880-888 19. Fehling J et al 2005. Harmful Algae 4: 763-769 20. Bates S et al 1995. Nat Toxins 3: 428-435 Authors: Nina Lundholm & Sara Harðardóttir, Natural History Museum of Denmark, Uni- versity of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark Email: nlundholmsnm.ku.dk HARMFUL ALGAE NEWS NO. 56 / 2017 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 56 - March 2017 www.ioc-unesco.org/hab Is Gambierdiscus expanding its geographic range in the Pacific region? Content HAB events and toxin effects Gambierdiscus distribution in the Pacific . ................................... Table 1: Geographic occurrence and toxin production (as determined by LCMS/MS) of Gambierdiscus species in the Pacific region. Species reported in the Pacific region G. australes G. balechii G. belizeanus G. caribaeus G. carpenteri G. cheloniae G. lapillus G. pacificus G. polynesiensis G. scabrosus Fig. 2. Scanning electron micrographs of cells of Gambierdiscus sp., isolate CAWD242, from the Kermadec Islands: (A) view of cingulum and apical pore, (B) apical pore complex, (C) antapi- cal hypotheca. this will bring the number of Gambier- discus species to fifteen. A related species, originally d lished data). The role of MTXs in ciguat- era fish poisoning is uncertain and due to its low oral toxicity may only play a small part in toxic events 21. A range of cell-based assays is avail- able to detect CFP-related toxins, includ- ing receptor binding (RBA), Ca 2+ flux, N2A and haemolytic assay Toxin production in lab-rat-diatoms (e.g. Pseudo-nitzschia) in the presence of copepods From only 15 species in 1965, currently 49 Pseudo-nitzschia species have been described, of which 22 have the abil- ity to produce the toxin domoic acid (DA), along with two Nitzschia species 1. Both numbers are Apart from increasing toxin produc- tion in already toxic species/strains, presence of grazers may even induce toxin production in species previously considered non-toxic, as shown for P. obtusa 3. It is therefore relevant to consider that all Pseudo-nitzschia spe- cies might have the potential to p Ecology of Alexandrium spp. in the Strait of Georgia, British Columbia, Canada 2015 Fig. 1 Citizen Science sampling stations in the Strait of Georgia, Canada in 2015. Fig. 2. Citizen Science sampling areas in the Strait of Georgia, Canada in 2015. Coastal waters of British Columbia (BC), Canada have Table 1. Number of water samples (N) collected by the Citizen Science Program, frequency of samples with Alexandrium spp. presence (Alex. +), and number of water samples with Alexan- drium spp. cells present by month, Strait of Georgia 2015 (n/a - no samples were collected). Area Ladysmith Cowichan A clarification of three unnamed raphidophytes previously described from British Columbia gated motile cell with very similar chlo- roplasts and the oval Lugol-fixed cell in Fig. 2 #3 were probably equivalent to the long cells formed by V. globosus in stationary growth (see 5 Figs. 7 & 8). Raphidoph Fig. 3. Raphidophyte 2 from a culture in 1974. Motile cell, ventral view 11.5 μm long. reproduced here at a smaller size (Fig. 4) and are interpreted (in the figure caption) by the author. Photographs of motile cells under stress received from Nicky Haigh (Mi- crothalassia) (not shown here) reveal t Autumnal algal bloom succession in northern coasts of Gulf of Oman Fig. 1. Map of the study area The composition of harmful algal blooms is determined by the diversity and abundance of different species pre- sent. Temporal fluctuations in phyto- plankton populations can lead to a suc- cession of dif Table 1. Maximal mean density of the observed bloom species and physical-chemical properties of the near-shore waters during autumnal algal blooms in the northern Gulf of Oman Date 26 October 2016 04 November 2016 09 November 2016 29 November 2016 03 December 2016 Species/ Genus Alexandrium sp. Pror Nodularin accumulation in New Zealand shortfin eel from Lake Forsyth/Te Wairewa in 1866 2 and, from the 1940s onwards, open- ings have been carried out regularly. In 2008, the rūnanga attempted to create a permanent opening by constructing a 900 m canal and 300 m groyne at the eastern end of the bea Fig. 2. Nodularia spumigena from Lake Forsyth/Te Wairewa at 400 magnification (A) and blooms of the cyanobacterium at the lake in 2006 (B). Fig. 3. Eel fishing channels at Lake Forsyth/Te Wairewa (A) and members of the rūnanga of Wairewa catching eels in the channels by gaffing (B; photo provided by The Scottish Coastal Observatory Scotlands coastal environment is sub- ject to inherent variability resulting from short term processes such as tides and weather, the seasonal cycle, multi- annual cycles such as the North Atlantic Oscillation and larger scale influences such as climate change and oc The RedFANnetwork: a working group to deal with HABs in Mexico In October 2014 the network RedFAN (from the acronym in Spanish: Red temática sobre Florecimientos Algales Nocivos) was created with the financial support of the Mexican National Coun- cil of Science and Technology (CONA- CyT). This netw Caribbean Ciguatera Experts Discuss a Risk Management System for the IOCARIBE Region Over the past three decades the inci- dence of ciguatera has increased in the Caribbean countries by about 32 1. Despite the evidence of toxic events and their potential consequences on public health, fisheries and IOC/WESTPAC Scientists Shape the Future of Regional HAB Research More than twenty experts from coun- tries in the Western Pacific gathered in Nha Trang, Vietnam, 19-22 December 2016 to foster cooperation and define research priorities for Harmful Algal Blooms (HABs) in the region (Fig. 1). The East ing the ongoing HAB research and ca- pacity building efforts at these levels. Dr. Po Teen Lim presented the science and implementation plans of the IOC- SCOR sponsored new GlobalHAB re- search program (Fig. 3). It was widely recognized that national and regional efforts are complementary to global e In memory of Paul Harrison With great sorrow, we learned of the recent unexpected passing of our col- league, mentor and friend Paul J. Har- rison. Among his many contributions, Paul was a founding member of the Sci- entific Committee on Oceanic Research (SCOR) working Group 137 SCOR WG 137 Global supply, marine resources, climate change impacts and environmental protection. His voice and perspec- tive will be sorely absent. Paul will be greatly missed by those he touched, but especially by Victoria, his wife of 51 years, and their children Rachel, Richard and Christina. A scholarship fund th 11th International Conference on Modern and Fossil Dinoflagellates The University of Bordeaux (France) is the organiser of the 11 th International Conference on Modern and Fossil Dino- flagellates, DINO11, which will be held from 17 to 21 July 2017 at Bordeaux, France. This series of conference was IOC Qualifications in Identification and Enumeration of Harmful Marine Microalgae A now traditional IOC course on identi- fication of harmful marine microalgae, including optional workshops on enu- meration and culture techniques. The 2017 course will be held from 6 to 19 August at the IOC Science a Taxonomic Note Oceanography special issue Alexandrium catenella vs. A. fundyense The Nomenclature Committee for Algae has decided (Prudhomme van Reine, 2017) that the name Gonyaulax catenel- la (Alexandrium catenella) should not be rejected and that A. fundyense and A. catenella are conspecific havi