A Preliminary Study Of The Toxicity And Mechanism Of Karlodinium Veneficum To Marine Organisms

The harmful algal blooms broken out frequently and many kinds of HABs appeared in China in recent years. Karlodinium veneficum is a kind of toxic dinoflagellate and has broken out in China in recent years. This paper studied the preliminary effects of the toxicity and mechanism of Karlodinium veneficum to marine organisms which belong to different sizes and trophic levels. Including the effects of Karlodinium veneficum to the survival and breeding of Calanus sinicus, the effects to model organisms- Brachionu splicatilis, Artemia salina and Neomysis awatschensis, and the effects to Sebastods schlegelii. We also discuss the toxic mechanisms and toxicity pathways of Karlodinium veneficum.The Karlodinium veneficum has small effects to the survival rates of Calanus sinicus but it inhibited the eggs production rate and hatching rate of it. We found that it almost has no effects to the survival rates of Calanus sinicus. The survival rates all are over 80% in experiment groups in 96 h and it is no significant difference with the control groups. The Calanus sinicus ingest Karlodinium veneficum and as the density increased, the feeding rate increase in 24 h. But at the same density of Karlodinium veneficum and Skeletonema costatum, the marine organisms more lover Skeletonema costatum. The Karlodinium veneficum inhibited the eggs production rate and hatching rate of Calanus sinicus. The average eggs production rate and hatching rate is about 0.9 Eggs/ind·d and 66% in Karlodinium veneficum in 7 days. The average eggs production rate and hatching rate is about 1.9 Eggs/ind·d and 85% in Skeletonema costatum in 7 days. It is significant difference between them(P<0.05).We found that it has greater effects to Brachionu splicatilis, Artemia salina than Neomysis awatschensis and the effects of different fractions of Karlodinium veneficum are different on experimental organisms. The LC50( medium lethal concentration) of Brachionu splicatilis is about 3400cells/mL in 48 h. The LC50 of Artemia salina is about 4800cells/ mL in 96 h. The LC50 of Neomysis awatschensis is about 89000 cells/mL in 96 h. The cell lysate has greatest effects on Brachionu splicatilis and Neomysis awatschensis. The extracellular fluid has greatest effects on Artemia salina. This indicate that the toxic mechanisms and toxicity pathways of Karlodinium veneficum are different. The Brachionu splicatilis and Artemia salina ingest Karlodinium veneficum and as the density increased, the feeding rate increase in 24 h. But at the same density of Karlodinium veneficum and Skeletonema costatum, the marine organisms more lover Skeletonema costatum.We also found that it has greater effects to Sebastods schlegelii. The survival rate of Sebastods schlegelii is about 60% in 144 h when the density is 50000 cells /mL. The effects of different fractions of Karlodinium veneficum are different. The cell lysate and extracellular fluid have greater effects on Sebastods schlegelii. The survival rates are about 10% and 30% in 144 h. The cell suspension solution has less effects on Sebastods schlegelii. The survival rates is about 50% in 144 h.So we can concluded that Karlodinium veneficum has different effects to marine organisms and different toxic mechanisms and pathways. When the algal density is 104cells/mL(the algal blooms have existed), the Brachionu splicatilis and Artemia salina have been greatly influenced. It may has greater effects to Marine ecosystem and fishery resources if algal blooms break out and can know the hazard more comprehensive by studying the effects of harmful algal to different sizes and trophic levels organisms.