Introduction to Raphidophyceae IOC Certificate of Proficiency in Identification of Harmful Marine Microalgae University of Copenhagen 6-19 August 2017 Introduction to Raphidophyceae Jacob Larsen IOC Science and Communication Centre on Harmful Algae, Copenhagen, Denmark – jacobl@bio.ku.dk

Principal charateristics of Raphidophyceae from Hara & Chihara 1987 heterokont flagellates with 2 flagella, often difficult to observe in LM without cell wall, very fragile most species have nume-rous chloroplasts with chl a+c fucoxanthin in the marine representatives trichocysts or mucocysts present in most species

Raphidophyceae Golden Brown Raphidophytes Green Raphidophytes Vaucheriaxanthin derivatives freshwater species Gonyostomum Merotrichia Vacuolaria Chattonella marina. var. antiqua C. marina var. marina C. minima C. globosa C. marina var. ovata C. subsalsa C. verruculosa Chlorinimonas sublosa Fibrocapsa japonica Haramonas dimorpha H. pauciplastida H. viridis Heterosigma akashiwo Olisthodiscus luteus ? Psammamonas australis Dictyochophyceae Viciciius globosus Pseudochattonella verruculosa Golden Brown Raphidophytes Fucoxanthin dominated carotenoids marine/brackish water species

Chattonella marina var. antiqua

Chattonella subsalsa Principal characteristics 2 apical flagella 30-70 µm long oblong (drop-shaped) may cause fish kills widely distributed C. antiqua C. subsalsa 20 µm

Heterosigma akashiwo Principal characteristics 2 sub-apical flagella 8-25 µm long sack-of-potato-shaped may cause fish mortality widely distributed Lugol preserved

Fibrocapsa japonica

Fibrocapsa japonica Principal characteristics 2 apical flagella 20-30 µm long oval, slightly flattened mucocysts in the posterior end of the cell (arrow) may cause fish mortality widely distributed

Fish kills

Fish kills Occurrence of Ch. antiqua, marina, subsalsa, globosa, fish icons indicate blooms associated with mass mortality Occurrence of Ch. antiqua, marina, subsalsa, globosa, fish icons indicate blooms associated with mass mortality From Imai & Yamaguchi 2012

Fish kills Khan, S., O. Arawaka & Y. Onoue. 1996a. Neurotoxin production by a chloromonad Fibrocapsa japonica (Raphidophyceae). - Journal of the World Aquaculture Society. 27: 254-263. Khan, S., O. Arawaka & Y. Onoue. 1996b. A toxicological study of the marine phyto-flagellate, Chattonella antiqua (Raphido-phyceae). - Phycologia 35: 239-244. Khan, S., O. Arawaka & Y. Onoue. 1997. Neurotoxins in a toxic red tide of Hetero-sigma akashiwo (Raphidophyceae) in Kagoshima Bay, Japan. - Aquaculture Research 28: 9-14. from Khan et al. 1996a

Fish kills from Khan et al. 1996a

Fish kills Raphidophytes may produce Brevetoxins Reactive Oxygen Species Free Fatty Acids From Dorantes-Aranda et al. 2013

Genera of marine raphidophytes Chlorinimonas cell without tubular invagination cell yellow-green cell with tubular invagination cell golden-brown Few, 5-8-(13) chloroplasts Many chloroplasts, >10; cell not or only slightly compressed flagella inserted in an apical gullet, with posterior, rod-shaped mucocysts flagella inserted in an apical gullet; chloroplasts arranged radially flaqella inserted in a sub-apical or lateral oblique groove; cell ‘sack-of potato’-shaped + pyrenoids; cell regularly oval, strongly compressed; benthic Haramonas 2 forms; benthic stage irregularly discoid Chattonella Heterosigma Fibrocapsa Olisthodiscus Psammamonas

Identification of Raphidophyceae Species of raphidophytes are very fragile and usually cannot be identified to species in preserved samples – they may not even be recognized as raphidophytes Lugol preserved