Arctic-ICE 2012 Intracellular Nutrients

Nutrient availability influences maximum production, speciation, cellular composition, and overall phenology of the Arctic spring ice algal bloom. However, how ice algae obtain nutrients from their environment is not well-understood. Previously documented positive relationships between sea ice nutrient concentrations and algal biomass evidenced that ice algae maintain an intracellular nutrient pool. Here we provide direct evidence that **sea ice diatoms store intracellular nitrate+nitrite and silicic acid well above that available in their ambient environment**. Differential retention of intracellular pools released during standard melt processing techniques led to an increase in the apparent dissolved ratio of N:Si measured in bulk ice melt samples that likely influenced interpretations of Si-limitation in some previous studies. <br><br> The ability of ice algae to store nutrient reserves also highlights a critical biological process that stands to shift our understanding of nutrient dynamics in sea ice.营养盐可利用性会影响北极春季海冰藻华的最大生产力、物种组成、细胞组分以及整体物候学。然而，海冰藻类如何从所处环境获取营养盐，目前尚未得到充分阐明。既往研究中记录的海冰营养盐浓度与藻类生物量之间的正相关关系，证明海冰藻类会维持胞内营养盐库。本研究提供了直接证据，表明**海冰硅藻（sea ice diatoms）所储存的胞内硝酸盐+亚硝酸盐与硅酸浓度，远高于其所处环境中的可利用水平**。在标准融样处理流程中释放的胞内营养盐库存在差异性留存，导致整体冰融样品中测得的溶解态N:Si表观比值升高，这一现象可能影响了此前部分研究中关于硅限制的解读。 海冰藻类储存营养盐储备的能力，也揭示了一个关键的生物学过程，有望改变我们对海冰营养盐动力学的认知。