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Groundwater is a keystone ecosystem vital for our planet's health

In an era where environmental concerns are escalating, an international study has redefined the importance of groundwater, classifying it as a keystone ecosystem that is vital for sustaining biodiversity and mitigating the impacts of climate change. This new perspective demands greater protection of groundwater.

Underappreciated role of groundwater

Despite being fundamental to life on Earth, groundwater’s significance in sustaining biodiversity is often overlooked. 

The research team, including Professor Robert Reinecke of Johannes Gutenberg University Mainz, emphasizes the need to view groundwater as a critical ecosystem.

“Groundwater is not only in itself a major ecosystem but is also of critical relevance to ecosystems on the Earth’s surface,” explained Professor Reinecke. 

Largest unfrozen freshwater reserve

Groundwater is the planet’s largest reservoir of unfrozen freshwater, and is essential for almost half of the global urban population’s drinking water needs. Countries like Denmark rely entirely on groundwater for their drinking water. 

“Throughout the world, some 1,000 cubic kilometers of water are pumped to the Earth’s surface every year. Sadly, we consume far more than what is naturally replenished,” said Professor Reinecke. 

This overconsumption has put about a third of the largest groundwater basins at risk of depletion.

Overlooked ecosystem dependence 

Ecosystems’ reliance on groundwater has been consistently ignored in global biodiversity conservation efforts. 

Approximately 52 percent of all surface areas interact significantly with groundwater. This interaction is critical as groundwater feeds wetlands, rivers, and other surface water areas. 

“Interaction in this context means that water from rivers and lakes enters the groundwater while groundwater, in its turn, rises to the surface and feeds wetlands, rivers, and other kinds of surface water areas.” 

Professor Reinecke added that groundwater is also a valuable habitat for thousands of different subterranean creatures, including cavefish, blind eels, and transparent shrimp.

Keystone species 

“Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes,” wrote the researchers. 

“To foster timely global conservation of groundwater, we propose elevating the concept of keystone species into the realm of ecosystems, claiming groundwater as a keystone ecosystem that influences the integrity of many dependent ecosystems.”

Groundwater protection

In Germany, as pointed out by Professor Reinecke, groundwater is not legally recognized as a habitat but merely as a resource, which limits its protection. 

He stresses the urgent need for policy changes, citing data from the German Environment Agency that reveals poor chemical quality in about 32 percent of German groundwater bodies, primarily due to nitrate and pesticide pollution.

Conservation agenda

The researchers advocate for eight key themes to establish a science-policy integrated groundwater conservation agenda. They emphasize the intersection of above and below ground ecosystems and the role of groundwater in maintaining the planet’s health.

“Water is indispensable to life on Earth. If we don’t pay sufficient attention to the ecological integrity of the freshwater resources of our planet, we not only put the sustainability of whole ecosystems at risk but we also jeopardize our own way of life,” concludes Reinecke. 

The research is published in the journal Global Change Biology

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