Feeding by the Newly Described Mixotrophic Dinoflagellate Paragymnodinium shiwhaense: Feeding Mechanism, Prey Species, and Effect of Prey Concentration
Feeding by the Newly Described Mixotrophic Dinoflagellate Paragymnodinium shiwhaense: Feeding Mechanism, Prey Species, and Effect of Prey Concentration
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新描述的混合营养型甲藻 Paragymnodinium shiwhaense 的摄食：摄食机制、猎物种类和猎物浓度的影响
DOI：
10.1111/j.1550-7408.2009.00448.x
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发表时间：
2010
影响因子：
2.2
通讯作者：
Ju
中科院分区：
文献类型：
--
作者：
Y. Yoo;H. Jeong;N. Kang;Jae Yoon Song;Kwang Young Kim;Gitack Lee;Ju
摘要。为了研究新描述的兼养甲藻Paragymptinium shiwhaense（GenBank登录号=AM408889）的摄食，我们使用几种不同类型的显微镜，包括透射电子显微镜和高分辨率视频显微镜，探索了P. shiwhaense能够摄食的摄食过程和猎物种类。此外，我们测量了生长和摄食率的P. shiwhaense其最佳的藻类猎物前沟藻carterae作为猎物浓度的函数。我们还在单一浓度下测量了可食用猎物的这些参数，在该浓度下，潮华对虾在A上的生长和摄食率。carterae饱和。志华副甲藻用一根拖丝锚定猎物后，用一个花梗捕食藻类猎物。结果表明，在所捕食的藻类中，潮滩拟青霉主要捕食等效球径≤11 μm的小型藻类（如球等鞭金藻、隐藻Teleaulax sp.和Rhodiumsalina、针藻赤潮异弯藻、甲藻Heterocapsa rotundata和A. carterae）。然而，它不以ESD ≥12 μm的大型藻类（例如甲藻Prorocentrum minimum、Heterocapsa triquetra、Scrippsiella trochoidea、Alexandrum tamarense、Prorocentrum micans、Gymatrium catenatum、Akashiwo sanguarum和Lingulodinium polyedrum）或小型硅藻中肋骨条藻为食。 结果表明，潮滩对虾以A. carterae迅速增加，增加平均猎物浓度之前饱和的浓度。350 ng C/ml（5，000个细胞/ml）。 潮华对虾在A.在20 °C、20 μE/m2/s的14：10h光暗循环条件下，carterae的生长速率为1.097/d，而在相同光照条件下不添加猎物时，其生长速率（即光养生长）为-0.224/d。 潮华对虾对A.每头食草动物每天5.4个细胞，每头食草动物每天0.38 ng C，每头食草动物每天0.7 μl。 计算的放牧系数P. shiwhaense对共同发生的前沟藻spp. 07/h（即前沟藻种群的6.7%）。在1 h内被芝华松种群所清除。 本研究的结果表明，P. shiwhaense可以有相当大的放牧对藻类种群的影响。
ABSTRACT. To investigate the feeding by the newly described mixotrophic dinoflagellate Paragymnodinium shiwhaense (GenBank accession number=AM408889), we explored the feeding process and the kinds of prey species that P. shiwhaense is able to feed on using several different types of microscopes, including a transmission electron microscope and high‐resolution video‐microscopy. In addition, we measured the growth and ingestion rates of P. shiwhaense on its optimal algal prey Amphidinium carterae as a function of prey concentration. We also measured these parameters for edible prey at a single concentration at which the growth and ingestion rates of P. shiwhaense on A. carterae were saturated. Paragymnodinium shiwhaense feed on algal prey using a peduncle after anchoring the prey by a tow filament. Among the algal prey offered, P. shiwhaense ingested small algal species that had equivalent spherical diameters (ESDs) ≤11 μm (e.g. the prymnesiophyte Isochrysis galbana, the cryptophytes Teleaulax sp. and Rhodomonas salina, the raphidophyte Heterosigma akashiwo, and the dinoflagellates Heterocapsa rotundata and A. carterae). However, it did not feed on larger algal species that had ESDs ≥12 μm (e.g. the dinoflagellates Prorocentrum minimum, Heterocapsa triquetra, Scrippsiella trochoidea, Alexandrium tamarense, Prorocentrum micans, Gymnodinium catenatum, Akashiwo sanguinea, and Lingulodinium polyedrum) or the small diatom Skeletonema costatum. The specific growth rates for P. shiwhaense feeding upon A. carterae increased rapidly with increasing mean prey concentration before saturating at concentrations of ca. 350 ng C/ml (5,000 cells/ml). The maximum specific growth rate (i.e. mixotrophic growth) of P. shiwhaense on A. carterae was 1.097/d at 20 °C under a 14:10 h light–dark cycle of 20 μE/m2/s, while its growth rate (i.e. phototrophic growth) under the same light conditions without added prey was −0.224/d. The maximum ingestion and clearance rates of P. shiwhaense on A. carterae were 0.38 ng C/grazer/d (5.4 cells/grazer/d) and 0.7 μl/grazer/h, respectively. The calculated grazing coefficients for P. shiwhaense on co‐occurring Amphidinium spp. was up to 0.07/h (i.e. 6.7% of the population of Amphidinium spp. was removed by P. shiwhaense populations in 1 h). The results of the present study suggest that P. shiwhaense can have a considerable grazing impact on algal populations.