# Bryophytes promote the development of soil function on karst rock surfaces

## TL;DR

Bryophytes help develop soil on karst rocks by increasing organic matter and beneficial microbes, aiding ecosystem restoration.

## Contribution

This study identifies specific microbial and chemical changes caused by bryophytes in karst rock ecosystems.

## Key findings

- Bryophyte-covered rocks had higher soil organic carbon and nitrogen but lower phosphorus and potassium.
- Bryophytes increased microorganisms involved in nitrogen fixation, carbon sequestration, and phosphorus metabolism.
- Certain bacteria were positively correlated with specific soil acid and nutrient levels.

## Abstract

Bryophytes is a pioneer plant in the development of karst ecosystems and plays an important role in altering the surface environment of rocks. Studying the interaction mechanism between bryophyte and rock surface environment in karst can reveal the role of bryophyte in karst ecosystems and provide technical methods for the restoration of rocky desertification.

By comparing the soil fertility, organic acids, microbial diversity, and community composition in the rock surface covered with bryophyte or without.

The experimental results show that when the rock surface covered with bryophyte, the overall contents of soil organic carbon (SOC) and total nitrogen (TN) was increased, whereas the contents of total phosphorus (TP) and total potassium (TK) decreased. And Hyophila involute can increase the content of malic acid and acetic acid in rock surface. In addition, the growth rates of various microorganisms were as follows: fungi, 52%; bacteria, 11%; eukaryotes, 78%; Archaea, 27%; and viruses, 146% in the rock surface covered with bryophyte. The number of carbon-fixing microorganisms increased by 37%, the number of nitrogen-fixing microorganisms increased by 49%, and the number of phosphorus-metabolizing microorganisms increased by 53% in the rock surface covered with bryophyte. Acidimimicrobia_bacterium, Acidimimicrobiaceae_bacterium, Acidimimicrobiales_bacterium, and Iamiaceae_bacterium_SCSIO_58843 were significantly positively correlated with the potassium content in the soil. Alphaprotoobjective_bacterium, Solirubrobacteriales_bacterium, and Betaproteobjective_bacterium were significantly positively correlated with the succinic acid content in the soil. Chloroflexi_bacterium was significantly positively correlated with the oxalic acid content in the soil.

Bryophytes can increase the number of microorganisms related to nitrogen fixation, carbon sequestration, phosphorus metabolism, as well as soil nitrogen, organic carbon, and malic acid content, promoting the positive succession of rock surface ecosystems.This study makes it possible to use lithophytic bryophyte to control the bare rock of rocky desertification.