1:45 PM - 2:00 PM
[ACG43-12] The prevalence of infection of chytrid fungus on glacier algae on Gulkana Glacier in Alaska
Keywords:chytrids, glacier algae, fungi, cryoconite hole, glacier, Alaska
The melting rate of Arctic glaciers has increased recently due to darkening of the glacier surface as well as climate warming. One of the reasons of the darkening is blooming of glacier algae, which have dark-colored pigments in their cells. The blooming of glacier algae is likely controlled by environmental conditions of the glacier surface, but also by infections with chytrids fungi. Chytrids is one of the groups of fungi that form zoospores with a flagellum in their life cycle. Some of chytrids are parasitic and have an great impact on ecosystems, causing extinction and/or population dynamics of host species. Therefore, it is important for assessment of ecosystems and melting process of glaciers to understand ecology of chytrids parasitizing glacier algae. The purpose of this study is to describe morphology, distribution of chytrids, and the prevalence of infection on algal cells using snow and ice samples collected on Gulkana Glacier in Alaska.
The samples used for the analysis was collected on cryoconite hole, ice surface, and snow surface of five sites of different altitudes on Gulkana Glacier in Alaska in August 2015. The fluorescent dye, Calcoflor White, which specifically stains fungi (chitin), was used for microscopy. Morphological characteristics of chytrids parasitizing glacier algal cells was observed with a fluorescence microscope and the frequency of parasitism on algae was calculated by counting the presence or absence of Chytrid on the algal cell.
There were mainly five morphological types of Chytrids infecting the algal cells of Ancylonema nordensholdii, Ancylonema alaskana, Chloromonas sp., and Sanguina sp. on this glacier. The type of chytrids infecting each alga was distinctive among the algal species, indicating that each chytrid can infect specific algal species. The prevalence of infection of Chytrids with algae varied among the algal species. The variation may be due to the properties of algal cells such as surface area and thickness of cell wall. The prevalence of infection also varied among the different types of habitats on the glacier. It was significantly higher in cryoconite holes than on the ice surface. This is probably due to static environment of melt water in cryoconite holes, which allow the chytrid zoospores actively moving in the water.
The samples used for the analysis was collected on cryoconite hole, ice surface, and snow surface of five sites of different altitudes on Gulkana Glacier in Alaska in August 2015. The fluorescent dye, Calcoflor White, which specifically stains fungi (chitin), was used for microscopy. Morphological characteristics of chytrids parasitizing glacier algal cells was observed with a fluorescence microscope and the frequency of parasitism on algae was calculated by counting the presence or absence of Chytrid on the algal cell.
There were mainly five morphological types of Chytrids infecting the algal cells of Ancylonema nordensholdii, Ancylonema alaskana, Chloromonas sp., and Sanguina sp. on this glacier. The type of chytrids infecting each alga was distinctive among the algal species, indicating that each chytrid can infect specific algal species. The prevalence of infection of Chytrids with algae varied among the algal species. The variation may be due to the properties of algal cells such as surface area and thickness of cell wall. The prevalence of infection also varied among the different types of habitats on the glacier. It was significantly higher in cryoconite holes than on the ice surface. This is probably due to static environment of melt water in cryoconite holes, which allow the chytrid zoospores actively moving in the water.