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.
Subject(s)
Ecosystem , Groundwater , Biodiversity , Fresh Water , Environmental PollutionABSTRACT
Contamination of potable groundwater by pathogenic viruses from on-site wastewater treatment systems (OWTS) poses a serious health risk. This study investigated the attenuation and transport of rotavirus, bacteriophage MS2 and DNA-labelled-glycoprotein-coated silica nanoparticles (DGSnp) in 2 intact cores of silt loam over gravels dosed with wastewater from an OWTS at 3.53â¯L/day. To simulate a worst-case scenario, experiments were conducted under saturated conditions. The results from 6 experiments demonstrated that the rotavirus and DGSnp reductions were very similar and markedly greater than the MS2 reduction. This was reflected in the peak concentrations, relative mass recoveries, and temporal and spatial reduction rates. For a given log10 reduction, the estimated soil depth required for MS2 was over twice that required for rotavirus and DGSnp. This is the first study in which DGSnp was used as a rotavirus surrogate in soil under wastewater applications. Consistent with previous studies, DGSnp showed promise at mimicking rotavirus attenuation and transport in porous media. The results suggest DGSnp could be used to assess the attenuation capacity of subsurface media to rotavirus. However, DGSnp is not conservative and will underestimate the setback distances required for rotavirus reductions by 3%. On the other hand, separation distances determined using the rotavirus parameters and criteria but based on MS2 attenuation, can be too conservative in some subsurface media. To determine safe and realistic separation distances, it would be beneficial and complementary to apply both conservative virus surrogate using MS2 bacteriophage and representative but non-conservative new virus surrogates using biomolecule-modified silica nanoparticles.