海洋尖尾藻的营养升级功能研究

异养甲藻作为连接浮游动物和浮游植物的中间环节，在海洋生态系统物质循环和能量流动过程中具有关键作用。本文以异养甲藻的模式生物——海洋尖尾藻作为实验对象，研究了海洋尖尾藻在摄食土生杜氏藻、赤潮异弯藻、球形棕囊藻、盐生舟形藻4种浮游植物后脂肪酸种类和含量的变化。研究表明:海洋尖尾藻对4种浮游植物均可摄食，但是对杜氏藻摄食率远高于其他3种浮游植物。4种浮游植物细胞内均未检出二十二碳六烯酸，摄食了4种浮游植物后的海洋尖尾藻细胞中均含有二十二碳六烯酸，含量最高可达（86.98±7.44）μg/mg C，表明其具有独立合成二十二碳六烯酸的能力。海洋尖尾藻独立合成脂肪酸的能力表明其有能力将低质量的物质升级为营养物质，从而高效的供应二十二碳六烯酸达到下一营养级。

Trophic upgrading of essential fatty acids by Oxyrrhis marina

Heterotrophic dinoflagellates serve as an intermediate bridge connecting zooplankton and phytoplankton, and play a key role in material recycling and energy flowing in marine ecosystems.In this paper, fatty acid of heterotrophic dinoflagellate Oxyrrhis marina was analyzed after feeding on four phytoplankton, including Dunaliella tertiolecta, Heterosigma akashiwo, Phaeocystis globosa, and Navicula salinarum.Research shows that O.marina can feed on four kinds of phytoplankton, but ingestion rate on D.tertiolecta was higher than those on other three species.DHA (docosahexaenoic acid) was not observed in all prey, but found in the O.marina fed on them with the content up to (86.98±7.44) μg/mg C.These results indicate that O.marina can synthesize DHA independently, which means that O.marina had the ability to upgrade the nutritional value of phytoplankton, thereby efficiently delivery docosahexaenoic acid to the next trophic level.