Microscopic life on volcanic ice giants: diatoms of the Ecuadorian glaciers
Ecuador, despite its small size, is recognized as one of the most biodiverse territories on the planet. This megadiversity is expressed both in its biological richness and in the variety of its ecosystems, distributed across four well-defined natural regions: the Coast, the Amazon, the Galápagos Islands, and the Andes. (Carpio, 2018; Mestanza-Ramón et al., 2020, 2023)
As one of the seven countries crossed by the Andes mountain range, Ecuador is home to a remarkable concentration of active volcanoes, including Cotopaxi, Antisana, Chimborazo, Carihuairazo, and Cayambe. These structures display variable dynamics: periods of volcanic activity marked by the emission of lava and ash alternate with phases in which their summits remain blanketed by snow and glaciers that shelter microscopic communities. (Caceres, B., Francou, B., Favier, V., Bontron, G., Tachker, P., Bucher, R., & Chazarin, 2006; Francou et al., 2004; Yallop & Anesio, 2010).
Studying these ice giants presents significant physical and logistical challenges, given the high-altitude conditions at elevations ranging from 3,000 to 6,000 meters. From a scientific standpoint, it requires addressing questions about the presence of life in these environments, the functioning of glaciers as ecosystems, and the structure of their biological communities
It has been documented that glaciers harbour microscopic life, including bacteria, fungi, and diatoms, photosynthetic microalgae that play an important role in oxygen production. However, until 2018, Ecuador’s glaciers lacked systematic biological exploration: prior studies had been limited to monitoring glacial retreat, without characterizing the associated microbial communities (Vinšová et al., 2015; Yallop & Anesio, 2010).
The first expedition took place on the Antisana glacier, an active volcano, where sampling was carried out up to 5,200 meters above sea level. The objective was to identify the presence of cryoconite holes: cylindrical cavities formed on the glacier surface by the deposition of dark particles transported by the wind. These particles absorb solar radiation, trigger localized melting, and create aqueous micro-environments rich in sediments that are favourable for the development of microbial communities.
The results revealed the presence of diatoms with a richness and diversity exceeding that documented in comparable glacial ecosystems, including cosmopolitan species, species typical of cryophilic environments, and new records both for Ecuador and for science. These findings established a methodological foundation for subsequent studies on the Cotopaxi, Carihuairazo, and Cayambe glaciers.
Subsequent investigations revealed variations in the composition and diversity of communities within each glacier and between glaciers, linked to the specific environmental conditions and characteristics of each volcano. A particularly significant finding was the presence of Psammothidium germainii (Manguin) Sabbe, across all four glaciers studied. This species has not been recorded in any other aquatic ecosystem in the country, suggesting a possible ecological specialization associated with Ecuador’s tropical volcanic glaciers, with direct implications for the conservation of these unique environments.
Building on data collected from these glaciers, ongoing research is now focused on integrating optical identification methods with molecular metabarcoding techniques applied to diatom communities in tropical glaciers. The study combines optical microscopy and molecular sequencing to evaluate the consistency and complementarity of both approaches in species identification.
This approach is especially relevant in tropical regions, where genetic studies on diatoms are recent and global databases are under-representative of tropical species. In Ecuador, although targeted diatom studies exist in various parts of the country, the use of diatoms for ecological assessment and as bioindicators of environmental quality is still emerging. The results will help strengthen the knowledge base and provide reliable, robust information to support decision, making in water resource management.
Susana Chamorro Arias is an Ecuadorian ecologist and researcher holding a PhD in Functional and Applied Ecology. She currently serves as an Associate Researcher and Lecturer at the Universidad Internacional del Ecuador (UIDE), maintains an ongoing collaboration with the Diatomology Laboratory at UNILEON, and is an active member of the International Network of Spanish-Speaking Diatomologists. Her research spans Ecuador’s four natural regions. In the Galápagos Islands, in collaboration with the Charles Darwin Foundation, she has worked on biodiversity studies, invasive species management, and pollinator ecology. On the Ecuadorian mainland, her research has focused on freshwater ecosystems: rivers, lakes, and tropical glaciers — with an emphasis on the use of diatoms as ecological indicators for assessing environmental quality and supporting long-term ecological monitoring.