PDF(Pubmed)
Abstract：
Eukaryotic phytoplankton, also known as algae, form the basis of marine food webs and drive marine carbon sequestration. Algae must regulate their motility and gravitational sinking to balance access to light at the surface and nutrients in deeper layers. However, the regulation of gravitational sinking remains largely unknown, especially in motile species. Here, we quantify gravitational sinking velocities according to Stokes\' law in diverse clades of unicellular marine microalgae to reveal the cell size, density, and nutrient dependency of sinking velocities. We identify a motile algal species, Tetraselmis sp., that sinks faster when starved due to a photosynthesis-driven accumulation of carbohydrates and a loss of intracellular water, both of which increase cell density. Moreover, the regulation of cell sinking velocities is connected to proliferation and can respond to multiple nutrients. Overall, our work elucidates how cell size and density respond to environmental conditions to drive the vertical migration of motile algae.
摘要：
真核浮游植物，也被称为藻类，形成海洋食物网的基础，推动海洋碳固存。藻类必须调节其运动性和重力下沉，以平衡表面的光线和深层的养分。然而,重力下沉的调节在很大程度上仍然未知，尤其是在活动物种中。这里,我们根据Stokes定律在不同的单细胞海洋微藻分支中量化重力下沉速度，以揭示细胞大小，密度,和下沉速度的营养依赖性。我们确定了一种活动藻类，Tetraselmissp.,由于光合作用驱动的碳水化合物积累和细胞内水的流失，饥饿时下沉更快，两者都增加了细胞密度。此外，细胞下沉速度的调节与增殖有关，并可以对多种营养素作出反应。总的来说,我们的工作阐明了细胞大小和密度如何响应环境条件，以驱动活动藻类的垂直迁移。
