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Accueil du site → Master → Etats Unis → 2014 → Improving ecosystmem function : Facilitating restoration of degraded biocrusts using mixed culture inoculation

SAN DIEGO STATE UNIVERSITY (2014)

Improving ecosystmem function : Facilitating restoration of degraded biocrusts using mixed culture inoculation

Muczynski, Sharon

Titre : Improving ecosystmem function : Facilitating restoration of degraded biocrusts using mixed culture inoculation

Auteur : Muczynski, Sharon

Université de soutenance : SAN DIEGO STATE UNIVERSITY

Grade : Master of Science (MS) 2014

Résumé
In arid and semiarid ecosystems where physiological constraints prevent most vascular plant establishment, the biological soil crust (biocrust) community is ecologically critical. The key to the survival of biocrust is the versatility and adaptability of cyanobacteria and green algae. The organismal construct of the biocrust community is especially vulnerable to compressional forces, and is slow to recover without assistance. Given the importance of biocrusts to so many aspects of healthy ecosytem function, it would be advantageous if land managers prioritized restoring damaged biocrusts. Coastal sage scrub (CSS) is a unique and imperiled valuable habitat and is nearly unmatched in the biodiversity of unique plants and animals. Recent work in biocrust restoration finds that assisted restoration speeds recovery of functionality in biocrusts. At present, studies of biocrust restoration in CSS habitat do not exist. This study examines the feasibility of isolating and culturing a mix of endemic CSS cyanobacteria and green algae to inoculate native CSS soil, thereby facilitating recovery of disturbed biological soil crusts. It further looks at markers for culture growth, chlorophyll a, extractable polysaccharides, and stability, to gauge whether inoculation and growth of the culture have increased soil function. Growth of the mixed culture and increases in functionality are compared between autoclaved soil inoculations and native soil inoculations to determine the extent that native crust organisms can regrow without inoculation, and how the inoculum interacts with the native microbial community. A putative novel genus and species of cyanobacteria related to Leptolyngbya was isolated and tentatively included in the genus, Trichotorquatus. The mixed culture included a green algae, possibly a species of Trebouxia. Mixed inoculum added to native soil significantly increased chorophyll a levels and soil stability, and increased extractable polysaccharides after just two months, demonstrating recovery of function. Autoclaving soil reduced increases in functionality indicating the importance of the intact soil community for growth. It may be possible in the future to restore biocrust in CSS using mixed culture inoculation

Mots clés : Ecology, Biological soil crust, Semiarid ecosystems, Arid ecosystems, Biological sciences

Présentation (Gradworks)

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