Fungal Thermophile Survey at the Sevilleta National Wildlife Refuge, New Mexico

Summary

Abstract: 

Biological soil crusts (BSCs) are complex assemblages of fungi, lichens, bacteria, mosses and green algae that stabilize surface soils and manage and traffic photosynthate, nutrients and water to diverse microbial and producer communities in arid environments worldwide.  In Sevilleta grasslands, BSCs occupy much of the open space between clumps of vegetation and vary substantially in terms of structure. 

BSCs have important biological and physical roles.  They have been termed ‘mantles of fertility’ because of their general importance in biogeochemical cycling and net primary production in arid ecosystems.  It has been proposed that BSCs play a role in the rapid movement of N, C and water from open areas to plants (see below).  BSCs stabilize soils, and physical and chemical disturbances of BSCs lead to topsoil loss and dust storms.  BSCs are therefore critical components in efforts to understand implications of both climate change and physical disturbance.  Related to this, it has been suggested that BSC diversity can be used to inform conservation policies.

BSCs have been the subject of several previous Sevilleta LTER studies.  Green et al. showed that stable-isotope carbon and nitrogen could be transferred bi-directionally between BSCs and adjacent plants.  This led Collins et al. to propose that fungal hyphae provide connections between plant roots and BSCs that allow for transport between the two, a proposal known as the “fungal loop hypothesis.”  Porras-Alfaro et al. have surveyed the diversity of fungi in BSCs from Sevilleta grasslands using molecular methods.  We have also shown that thermophilic fungi are common in BSCs (unpublished results), a result that is not unexpected given the high summer temperatures attained in Sevilleta surface soils.  Yet, many questions remain regarding the organisms present in BSCs, their biological roles and how long it takes for BSCs to re-establish after disturbance.  Long-term, we are interested in the types of fungi present in BSCs and in how fungi function in transporting nutrients between BSCs and adjacent plants.  We are also interested in the extent to which specific fungi provide structure to BSCs and in how they help protect from stress agents such as desiccation.  We are interested in the extent to which fungi might help BSCs tolerate high summer soil temperatures, which often reach ≥ 60C.  We therefore have a special interest in thermophilic fungi present in the BSCs.  To date, little has been done to actually culture fungi from Sevilleta BSCs, hence the need for the current study.  

In summary, BSCs are one of the most important features of aridland ecosystems and form a critical interface between physical and biological domains.  Understanding the roles of BSCs in protecting soil structure, and in the cycling of carbon, water and nitrogen, is fundamental to aridland ecology.  The work proposed here continues efforts to characterize the specific fungi associated with Sevilleta BSCs.  It is a modest but important step toward addressing the long-term goals mentioned above.

Data set ID: 

281
Categories
Dates

Date Range: 

Friday, June 1, 2012 to Friday, June 15, 2012

Publication Date: 

Thursday, July 26, 2012
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Data Manager