Graduate School of Science and Engineering, Chiba University, Chiba, Japan.
Department of Earth Sciences, Graduate School of Science, Chiba University, Chiba, Japan.
Sci Rep. 2023 Mar 9;13(1):3973. doi: 10.1038/s41598-023-30721-w.
Glacier algae, which are photosynthetic microbes growing on ice, considerably reduce the surface albedo of glaciers and accelerate their melting rate. Although the growth of glacier algae can be suppressed by parasitic chytrids, the impact of chytrids on algal populations is still largely unknown. In this study, we described the morphology of the chytrid infecting the glacier alga Ancylonema nordenskioeldii and quantified the prevalence of infection in different habitats on a mountain glacier in Alaska, USA. Microscopic observations revealed three different morphological types of chytrids with distinct rhizoid shapes. Variations in the size of the sporangia were probably because of their different growth stages, indicating that they actively propagated on the glacier. The prevalence of infection did not vary among sites with different elevations but was substantially higher in cryoconite holes (20%) than on ice surfaces (4%) at all sites. This indicates that cryoconite holes are hot spots for chytrid infections of glacier algae, and the dynamics of cryoconite holes might affect the host-parasite interactions between chytrids and the glacier algae, which may in turn alter surface albedo and ice melting.
冰川藻类是生长在冰上的光合微生物，它们会显著降低冰川的表面反照率，加速冰川融化的速度。虽然寄生的壶菌可以抑制冰川藻类的生长，但壶菌对藻类种群的影响在很大程度上仍不清楚。在这项研究中，我们描述了感染冰川藻类Ancylonema nordenskioeldii 的壶菌的形态，并量化了在美国阿拉斯加一座山上的冰川不同栖息地中感染的流行率。显微镜观察显示，有三种不同形态的壶菌，其根状结构形状明显不同。游动孢子囊大小的变化可能是由于它们处于不同的生长阶段，这表明它们在冰川上积极繁殖。感染的流行率在不同海拔的地点之间没有差异，但在所有地点，冰穴（20%）中的感染率明显高于冰面（4%）。这表明冰穴是冰川藻类壶菌感染的热点，冰穴的动态变化可能会影响壶菌和冰川藻类之间的宿主-寄生虫相互作用，从而改变表面反照率和冰的融化。
