As a result of climate change, when ice melts in polar regions, rapid colonization of the newly deglaciated surface occurs. The first visible signs of change are the appearance of cryptogamic covers—structures formed by lichens, algae, or moss—that colonize soils left exposed after thousands of years beneath a thick layer of ice.
Source: Chile Desarrollo Sustentable
March, 2021.- The expansion of these covers is rapidly increasing in polar regions, but what changes are occurring in the soil, and what do they signify? This is what Asunción De los Ríos, a researcher at the National Museum of Natural Sciences (MNCN-CSIC), along with colleagues from the Centre for Functional Ecology at the University of Coimbra (CFE) and other institutions, analyzed in an article published in the journal Science of the Total Environment.
Soil ice from both polar regions
After analyzing soils from the two polar regions, namely Iceland and Livingston Island (Maritime Antarctica), they have found that soils from deglaciated areas with cryptogamic canopies are more fertile and show greater complexity and diversity.
"The covers stimulate soil development, make them richer and have greater bacterial diversity, as well as increase their enzymatic potential and functioning rates", says the MNCN researcher.
"This fact, which at first may seem positive, confirms that the ecosystem is undergoing changes. In reality, it indicates that polar ecosystems are altering their structure, but we don't yet know the long-term effects," says Jorge Duran, a researcher at the Centre for Functional Ecology and one of the investigators involved in this study.
The changes caused by the development of cryptogamic covers vary according to their ability to modify soil characteristics. In this study, they analyzed layers dominated by macroalgae, lichens or mosses, and found that different types of cryptogamic covers can modify the soil at different rates and ways.
Therefore, the scientist suggests that the degree of modifications in polar soils, due to the expected increase in the extent of cryptogamic covers in a context of climate change, will largely depend on what type of cryptogam is able to thrive under the new environmental conditions.
The role of cryptographic covers
In addition to lichens and mosses, cryptogamic covers can contain microorganisms such as bacteria, cyanobacteria, algae and fungi. A large part of the earth's surface, including soils and rocks, is covered by these structures. The relevance of these layers in polar zones is due to the fact that, in addition to being the first to occupy soils when the ice retreats, they favor the development of other more complex communities.
 |
| Greenland |
"The cryptogamic cover is the previous colonization that will later give way to the appearance of superior plants and, with this study, we help to understand how it facilitates soil development. For example, in the study we provide information on how microbial diversity or greenhouse gas fluxes between the soil and the atmosphere change when the soil is colonized by different types of cryptogamic cover", Duran explains.
"The extent of deglaciated areas due to the effect of climate change is increasing in many regions of the planet, hence we need to know the dynamics of colonization of these areas and the role played by cryptogamic covers in the biological process after the retreat of glaciers", concludes De los Rios.
This work is part of the CRYPTOBIOS project (CTM2015-64728-C2-2-R, MINECO/FEDER, EU) and is the result of the collaboration of researchers from MNCN-CSIC, Centre for Functional Ecology (University of Coimbra, Portugal), Institute of Landscape Ecology (University of Münster, Germany) and Icelandic Institute of Natural History (Iceland).
Comments
Post a Comment