Chemical composition of bedrock limits vegetation growth in karst regions, research shows

May 13, 2020

Scientists have revealed the critical role that the chemical composition of bedrock plays in limiting vegetation growth in some of the world's most barren and rocky terrains.

A team of international scientists, including Professor Tim Quine from the University of Exeter, has conducted pioneering new research into vegetation productivity in a karst region of Southwest China.

Covering around 15 per cent of the Earth's land surface, karst terrains are usually characterised as being barren, rocky ground - usually with caves and sinkholes - and an absence of surface lakes and streams.

Crucially, the areas have well-jointed, dense limestone found near the surface, and a moderate to heavy rainfall - with the water being able to percolate away through the rock, dissolving and removing the limestone as it goes.

While this topography is known to hinder vegetation productivity, the role that geochemistry of the bedrock - that is its chemical composition - plays in reducing plant growth has not been extensively studied.

In the new study, the research team used a 'critical zone approach' - studying an area that extends from the base of the weathered bedrock to the top of the vegetation canopy - across a typical karst region of southwest china.

They found significant variations in the chemical composition of the bedrock across the region, which influenced both the amount and the distribution of soil. They discovered that this, in turn, also played a pivotal role in controlling plant growth.

The researchers showed not only that plant productivity is controlled not by both the soil and the bedrock's ability to retain water, but also this in turn is controlled by bedrock's geochemistry.

The research team believe this is especially important when water is in short supply - the hottest driest months of the year - and during droughts.

They also believe that the findings offer a pivotal tool in helping authorities to optimise land use, as well as assessing ecosystem resilience and sensitivity to climate change climate.

The study is published in Nature Communications on Wednesday, May 13th 2020.

Professor Quine said: "Our international team and interdisciplinary critical zone approach have given us invaluable insight into bedrock controls on vegetation growth in the iconic landscapes of China's Karst zone. We have been able to show that bedrock chemistry provides us with a valuable quantitative measure of the capacity of ecosystems to retain the water that is essential to sustain plant growth through dry seasons and droughts."

Professor Hongyan Liu of Peking University, and principle investigator, said: "Our research also shows the global significance of the bedrock influence on vegetation productivity. We selected 12 of the main karst regions in the world, 10 of which show significant differences in vegetation productivity due to bedrock geochemistry".

Professor Meersmans of the University of Liege said: "This study highlights the importance of interdisciplinary research across the boundaries of soil-, plant- and geosciences in order to unravel the impact and interplay of various key factors determining primary production in karst regions. Moreover, the present study offers a basis for future research assessing the resilience of these fragile ecosystems when facing climate change and other environmental threats."

The research was carried out as part of the UK-China (NERC-NSFC) SPECTRA project, called Soil Processes and Ecological Services in the Karst Critical Zone of Southwest China, which aims to enhance the sustainable development of one of the poorest regions of China, Guizhou.

The Guizhou karst region, with a population of 35 million, is one of the poorest regions in China with a GDP less than 50% of the national average. In response to the environmental deterioration and changing social conditions in the Guizhou karst region, the Chinese government has intervened to promote the abandonment of the most degraded cultivated land and its succession to grassland, shrub and forest.

The SPECTRA project is designed to identify the biological controls on nutrient availability, soil formation and loss, and their response to perturbation, providing the rich evidence base needed to inform land management decision-making in the Guizhou province.
Bedrock geochemistry influences vegetation growth by regulating the regolith water holding capacity" is published in Nature Communications.

University of Exeter

Related Water Articles from Brightsurf:

Transport of water to mars' upper atmosphere dominates planet's water loss to space
Instead of its scarce atmospheric water being confined in Mars' lower atmosphere, a new study finds evidence that water on Mars is directly transported to the upper atmosphere, where it is converted to atomic hydrogen that escapes to space.

Water striders learn from experience how to jump up safely from water surface
Water striders jump upwards from the water surface without breaking it.

'Pregnancy test for water' delivers fast, easy results on water quality
A new platform technology can assess water safety and quality with just a single drop and a few minutes.

Something in the water
Between 2015 and 2016, Brazil suffered from an epidemic outbreak of the Zika virus, whose infections occurred throughout the country states.

Researchers create new tools to monitor water quality, measure water insecurity
A wife-husband team will present both high-tech and low-tech solutions for improving water security at this year's American Association for the Advancement of Science (AAAS) annual meeting in Seattle on Sunday, Feb.

The shape of water: What water molecules look like on the surface of materials
Water is a familiar substance that is present virtually everywhere.

Water, water everywhere -- and it's weirder than you think
Researchers at The University of Tokyo show that liquid water has 2 distinct molecular arrangements: tetrahedral and non-tetrahedral.

What's in your water?
Mixing drinking water with chlorine, the United States' most common method of disinfecting drinking water, creates previously unidentified toxic byproducts, says Carsten Prasse from Johns Hopkins University and his collaborators from the University of California, Berkeley and Switzerland.

How we transport water in our bodies inspires new water filtration method
A multidisciplinary group of engineers and scientists has discovered a new method for water filtration that could have implications for a variety of technologies, such as desalination plants, breathable and protective fabrics, and carbon capture in gas separations.

Source water key to bacterial water safety in remote Northern Australia
In the wet-dry topics of Australia, drinking water in remote communities is often sourced from groundwater bores.

Read More: Water News and Water Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to