Successional Development of the Phototrophic Community in Biological Soil Crusts on Coastal and Inland Dunes

Abstract

(1) Biological soil crusts (biocrusts) are microecosystems consisting of prokaryotic and eukaryotic microorganisms growing on the topsoil. This study aims to characterize changes in the community structure of biocrust phototrophic organisms along a dune chronosequence in the Baltic Sea compared to an inland dune in northern Germany. (2) A vegetation survey followed by species determination and sediment analyses were conducted. (3) The results highlight a varying phototrophic community composition within the biocrusts regarding the different successional stages of the dunes. At both study sites, a shift from algae-dominated to lichen- and moss-dominated biocrusts in later successional dune types was observed. The algae community of both study sites shared 50% of the identified species while the moss and lichen community shared less than 15%. This indicates a more generalized occurrence of the algal taxa along both chronosequences. The mosses and lichens showed a habitat-specific species community. Moreover, an increase in the organic matter and moisture content with advanced biocrust development was detected. The enrichment of carbon, nitrogen, and phosphorus in the different biocrust types showed a similar relationship. (4) This relation can be explained by biomass growth and potential nutrient mobilization by the microorganisms. Hence, the observed biocrust development potentially enhanced soil formation and contributed to nutrient accumulation.

Dynamics in eukaryotic algal communities regulate bacterial and fungal communities as biocrusts develop in a temperate desert in Central Asia

“…In this study, most of the detected algae were shared between the four successional stages of biocrust; that is, with the development of biological crusts, the algal species did not undergo significant changes. This is different from previous studies based on morphological observation that the species composition of eukaryotic algae in different stages of biological crusts is significantly different (Kammann et al., 2023; Schulz et al., 2016). This may be due to differences in the study area considering a previous study in this area that half of the recognized eukaryotic algae species are shared by four crusts (Zhang et al., 2009).…”

“…However, methodological limitations have led to differences in the identification of eukaryotic algae species. There are also obvious differences in the identification of eukaryotic algae in the same area by different researchers using morphological‐based approaches (Kammann et al., 2023; Schulz et al., 2016). This has greatly hindered our understanding of the distribution of eukaryotic algae in biological crusts.…”

“…The dynamics of the algal community is influenced by changing environmental properties during biocrust succession or seasonal variations. For example, the sampling season, meteorological factors such as precipitation, temperature and soil properties such as nitrogen and phosphorous content were reported to have significant effects on the composition of the eukaryotic algal community (Kammann et al., 2023; Rippin, Borchhardt, et al., 2018; Samolov et al., 2020).…”

Biocrusts protect the Great Wall of China from erosion

“…Similar climate-dominated patterns are found in biocrusts across the Negev Desert, Mojave Desert, and Colorado Plateau ( 14 ), and we provide further evidence to confirm that variation of biocrust type is regulated by climate ( 50 ). At a more advanced developmental level, moss biocrusts exceeded cyanobacterial biocrusts in thickness and biomass, with a denser surface, rhizoids stronger and thicker than cyanobacterial filaments, and more accumulation of soil organic matter ( 49 , 51 ). Thus, moss biocrusts exerted stronger protective functions than cyanobiocrusts under identical conditions.…”

“…Specifically, cyanobacterial and moss biocrusts had distinct habitat preferences; the more effective protectors were mosses that were more prevalent in semiarid rather than arid climates. These two groups are also part of a common successional sequence from early successional cyanobacteria, transitioning to mosses where the climate permits ( 49 ). Similar climate-dominated patterns are found in biocrusts across the Negev Desert, Mojave Desert, and Colorado Plateau ( 14 ), and we provide further evidence to confirm that variation of biocrust type is regulated by climate ( 50 ).…”