Ecological stoichiometry of the mountain cryosphere

ZE, R.; MARTYNIUK, N.; OLEKSY, I.; SWAIN, A.; HOTALING, S.

Frontiers in Ecology and Evolution

Frontiers Media S.A.

Año: 2019

2296-701X

Roughly 10% of the Earth?s surface is permanently covered by glaciers and ice sheets; in mountain ecosystems, this proportion of ice cover is often even higher. From an ecological perspective, ice-dominated ecosystems place harsh controls on life including cold temperature, limited nutrient availability, and often prolonged darkness due to snow cover for much of the year. Despite these limitations, glaciers support diverse, primarily microbial communities, though macroinvertebrates and vertebrates are also present. The availability and mass balance of key elements [(carbon (C), nitrogen (N), phosphorous (P)] are known to influence the population dynamics of organisms, and ultimately shape the structure and function of ecosystems worldwide. While considerable attention has been devoted to patterns of existing biodiversity in mountain cryosphere-influenced ecosystems, the ecological stoichiometry of these habitats has been less studied. Understanding this emerging research arena is particularly pressing in light of the rapid recession of glaciers and perennial snowfields in mountainous regions of the world. In this review, we synthesize existing knowledge of ecological stoichiometry in the mountain cryosphere (specifically glaciers and perennial snowfields) to develop a general framework and description of nutrient origin, availability, and trophic interactions in these often nutrient-limited habitats. We focus our efforts on three major habitats: glacier surfaces (supraglacial), beneath glaciers (subglacial), and adjacent downstream habitats (i.e., glacier-fed streams and lakes). We compare our results to similar studies of continental ice sheets (e.g., Greenland) and show that, in general, stoichiometric results measured for these regions do not reflect comparable mountain environments. We conclude by discussing how ongoing climate warming will alter nutrient and trophic dynamics in mountain glacier-influenced ecosystems. Finally, we highlight the pressing need for additional studies to understand spatial and temporal stoichiometric variation in the mountain cryosphere before these imperiled habitats vanish completely