Groundwater is a hidden global keystone ecosystem

Abstract

Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes. 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. Our global analysis shows that over half of land surface areas (52.6%) has a medium‐to‐high interaction with groundwater, reaching up to 74.9% when deserts and high mountains are excluded. We postulate that the intrinsic transboundary features of groundwater are critical for shifting perspectives towards more holistic approaches in aquatic ecology and beyond. Furthermore, we propose eight key themes to develop a science‐policy integrated groundwater conservation agenda. Given ecosystems above and below the ground intersect at many levels, considering groundwater as an essential component of planetary health is pivotal to reduce biodiversity loss and buffer against climate change.

(Micro-)Plastics in Saturated and Unsaturated Groundwater Bodies: First Evidence of Presence in Groundwater Fauna and Habitats

“…The potential residence time of MPs in groundwaters can be up to years [66], posing a significant ecological risk to resident fauna as well as to water quality. Finally, groundwaters often interact with surface waters [89]. The impact of MPs in groundwater could, therefore, extend to adjacent aquatic systems, spreading the ecological consequences beyond their point of origin.…”

Global‐Scale Groundwater Recharge Modeling Is Improved by Tuning Against Ground‐Based Estimates for Karst and Non‐Karst Areas

“…Groundwater abstractions lead to a decline in the groundwater table and a decrease in groundwater discharge to streams (de Graaf et al, 2019), the latter causing reduced seasonal low flows (Wittenberg, 2015). The decline of the groundwater table and discharge negatively impacts freshwater biota (Saccò et al, 2024) and increases the ratio of groundwater abstractions to groundwater recharge (GWR). Renewable groundwater use is a dynamically stable re-equilibrium of abstraction and GWR in the long term (Cuthbert et al, 2023).…”

Wie tief ist der Boden? Von belebten Strukturen und Kreaturen des Untergrunds

“…Saccò et al (2023) Die Grenzen der für subterrane Organismen noch akzeptablen Umweltbedingungen sind vielfach sehr eng; dies korrespondiert mit den eher stabileren Verhältnissen vieler subterraner Lebensräume gegenüber solchen der Oberfl äche.49 Mit den weiter vorne skizzierten Entwicklungen im Körperbau unterirdisch lebender Arten geht eine oftmals nur geringe Fähigkeit zur aktiven Ausbreitung einher. Insgesamt macht dies subterrane Organismen empfi ndlich gegenüber Veränderungen ihrer Umweltbedingungen.…”