Marine microalgae attack and feed on metazoans
Marine microalgae attack and feed on metazoans
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DOI：
10.1038/ismej.2012.29
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发表时间：
2012-10-01
期刊：
影响因子：
11
通讯作者：
Hansen, Per Juel
中科院分区：
文献类型：
--
作者：
Berge, Terje;Poulsen, Louise K.;Hansen, Per Juel
已知来自甲藻属Karlodinium的自由生活的微藻在全世界的富营养化沿海沃茨中形成大量水华，并且通常与鱼类死亡有关。最近发现，自然水华种群由两种兼养和有毒物种Karlodinium armiger和Karlodinium veneficum组成，在实验室中导致了有鳍鱼类和桡足类的快速麻痹和死亡，并与原位后生浮游动物生物量的减少有关。在这里，我们表明，K. armiger（K-0688）以密度依赖的方式固定常见的海洋桡足类Acartia tonsa，并集体摄取食草动物以促进其自身的生长速率。与此相反，4株K. veneficum不攻击或影响桡足类的运动和存活。桡足类固定化的K。armiger菌株是快速的（在15分钟内），并由群集细胞的攻击引起，可能是通过一种高效但未表征的神经毒素的转移和作用。桡足类以K.当密度低于1000个细胞/ml，但高于3500个细胞/ml时，混合营养甲藻固定、取食并杀死桡足类。将微藻的营养作用从桡足类的猎物转换为捕食者，将种群增长与放牧压力降低相结合，促进了高密度水华的持续性。K. armiger还以提供的其他三种后生动物有机体为食，这表明混合营养型甲藻的积极捕食可能直接参与造成海洋食物网几个营养级的死亡。The ISME Journal（2012）6，1926-1936; doi：10.1038/ismej.2012.29; 2012年4月19日在线发表
Free-living microalgae from the dinoflagellate genus Karlodinium are known to form massive blooms in eutrophic coastal waters worldwide and are often associated with fish kills. Natural bloom populations, recently shown to consist of the two mixotrophic and toxic species Karlodinium armiger and Karlodinium veneficum have caused fast paralysis and mortality of finfish and copepods in the laboratory, and have been associated with reduced metazooplankton biomass in-situ. Here we show that a strain of K. armiger (K-0688) immobilises the common marine copepod Acartia tonsa in a density-dependent manner and collectively ingests the grazer to promote its own growth rate. In contrast, four strains of K. veneficum did not attack or affect the motility and survival of the copepods. Copepod immobilisation by the K. armiger strain was fast (within 15min) and caused by attacks of swarming cells, likely through the transfer and action of a highly potent but uncharacterised neurotoxin. The copepods grazed and reproduced on a diet of K. armiger at densities below 1000 cells ml(-1), but above 3500 cells ml(-1) the mixotrophic dinoflagellates immobilised, fed on and killed the copepods. Switching the trophic role of the microalgae from prey to predator of copepods couples population growth to reduced grazing pressure, promoting the persistence of blooms at high densities. K. armiger also fed on three other metazoan organisms offered, suggesting that active predation by mixotrophic dinoflagellates may be directly involved in causing mortalities at several trophic levels in the marine food web. The ISME Journal (2012) 6, 1926-1936; doi:10.1038/ismej.2012.29; published online 19 April 2012