Assessing the viability of cyanobacteria pellets for application in arid land restoration

J R Román; A M Chilton; Y Cantón; M Muñoz-Rojas

doi:10.1016/j.jenvman.2020.110795

Assessing the viability of cyanobacteria pellets for application in arid land restoration

J Environ Manage. 2020 Sep 15:270:110795. doi: 10.1016/j.jenvman.2020.110795. Epub 2020 Jun 6.

Authors

J R Román¹, A M Chilton², Y Cantón³, M Muñoz-Rojas⁴

Affiliations

¹ Agronomy Department, University of Almería, Almería, Spain; Centro de Investigación de Colecciones Científicas de La Universidad de Almería (CECOUAL), University of Almería, Almería, Spain. Electronic address: jrf979@ual.es.
² Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, UNSW Sydney, 2052, Sydney, NSW, Australia.
³ Agronomy Department, University of Almería, Almería, Spain; Centro de Investigación de Colecciones Científicas de La Universidad de Almería (CECOUAL), University of Almería, Almería, Spain.
⁴ Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, UNSW Sydney, 2052, Sydney, NSW, Australia; School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, 6009, Australia; Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, Western Australia, 6005, Australia. Electronic address: m.munoz-rojas@unsw.edu.au.

PMID: 32721290
DOI: 10.1016/j.jenvman.2020.110795

Abstract

The role of cyanobacteria from soil biocrusts in restoring degraded land is gaining interest in recent years because of their critical role in enhancing soil fertility and preventing erosion. However, soil restoration through cyanobacterial inoculation remains a challenge for large-scale restoration efforts and new methodologies for effective cyanobacterial application need to be developed. Here, we propose a bioenvironmental approach to inoculate soils with pelletized cyanobacteria from soil biocrusts. Fresh cultures of three soil native cyanobacteria strains from two representative N-fixing genera (Nostoc and Scytonema) and a non-heterocystous filamentous genus (Leptolyngbya) were added into a substrate composed of commercial bentonite powder and sand (1:10 wt ratio) and extruded into pellets. Then, in two multifactorial microcosm experiments under glasshouse conditions, we evaluated (i) the survival and establishment over time of the cyanobacteria encapsulated in pellets, and ii) the viability of pelletized cyanobacteria after drying and storing for 30 d, on soils from three arid regions in Australia. Our results showed that pellets can dissolve completely and spread out in all treatments. Scytonema and the consortium of the three cyanobacteria species showed significant (P < 0.001) deeper CR₆₈₀ peaks, higher chlorophyll a contents and lower albedo compared to the other inoculation treatments. Storing the pellets for 30 d significantly affected the viability of the cyanobacteria inoculum with reductions of approximately 50% in chlorophyll a content (a proxy for cyanobacteria biomass). Overall, our results showed that some cyanobacteria species can be successfully incorporated into extruded pellets and survive on degraded soils. This technology opens a wide range of opportunities for application in large scale restoration programs although further testing and refining through field trials is recommended.

Keywords: Biocrust; Cyanobacteria inoculation; Drylands; Ecosystem restoration; Land degradation.

MeSH terms

Australia
Chlorophyll A
Cyanobacteria*
Desert Climate
Ecosystem
Soil
Soil Microbiology*

Substances

Soil
Chlorophyll A