Efficiency of sampling invertebrates in groundwater habitats

Gutjahr, Simon; Bork, Jörg; Schmidt, Susanne I.; Hahn, Hans Jürgen

doi:10.1016/j.limno.2012.08.001

Cited by 14 publications

(20 citation statements)

References 26 publications

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“…Based on our findings, it appears that sampling wells (without purging) is appropriate for assessing stygofauna diversity (richness), but multiple samples are generally required over time to capture all taxa using this method767879. Our results also question the suitability of using eDNA as a ‘stand alone’ method for stygofauna monitoring.…”

Section: Discussionmentioning

confidence: 79%

Wells provide a distorted view of life in the aquifer: implications for sampling, monitoring and assessment of groundwater ecosystems

Korbel

Chariton

Stephenson

et al. 2017

Sci Rep

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When compared to surface ecosystems, groundwater sampling has unique constraints, including limited access to ecosystems through wells. In order to monitor groundwater, a detailed understanding of groundwater biota and what biological sampling of wells truly reflects, is paramount. This study aims to address this uncertainty, comparing the composition of biota in groundwater wells prior to and after purging, with samples collected prior to purging reflecting a potentially artificial environment and samples collected after purging representing the surrounding aquifer. This study uses DNA community profiling (metabarcoding) of 16S rDNA and 18S rDNA, combined with traditional stygofauna sampling methods, to characterise groundwater biota from four catchments within eastern Australia. Aquifer waters were dominated by Archaea and bacteria (e.g. Nitrosopumilales) that are often associated with nitrification processes, and contained a greater proportion of bacteria (e.g. Anaerolineales) associated with fermenting processes compared to well waters. In contrast, unpurged wells contained greater proportions of pathogenic bacteria and bacteria often associated with denitrification processes. In terms of eukaryotes, the abundances of copepods, syncarids and oligochaetes and total abundances of stygofauna were greater in wells than aquifers. These findings highlight the need to consider sampling requirements when completing groundwater ecology surveys.

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Section: Discussionmentioning

confidence: 79%

Wells provide a distorted view of life in the aquifer: implications for sampling, monitoring and assessment of groundwater ecosystems

Korbel

Chariton

Stephenson

et al. 2017

Sci Rep

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“…Boreholes provide the only suitable sampling window into deeper non-karstic aquifers, and are commonly used for investigating invertebrates [14], [15] and microorganisms [16], [17]. Invertebrates within boreholes can be collected using nets, pumps, or traps [18], [19], but these samples are integrated over the water column and therefore the origin of the fauna within the aquifer is unknown.…”

Section: Introductionmentioning

confidence: 99%

Using Boreholes as Windows into Groundwater Ecosystems

et al. 2013

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Groundwater ecosystems remain poorly understood yet may provide ecosystem services, make a unique contribution to biodiversity and contain useful bio-indicators of water quality. Little is known about ecosystem variability, the distribution of invertebrates within aquifers, or how representative boreholes are of aquifers. We addressed these issues using borehole imaging and single borehole dilution tests to identify three potential aquifer habitats (fractures, fissures or conduits) intercepted by two Chalk boreholes at different depths beneath the surface (34 to 98 m). These habitats were characterised by sampling the invertebrates, microbiology and hydrochemistry using a packer system to isolate them. Samples were taken with progressively increasing pumped volume to assess differences between borehole and aquifer communities. The study provides a new conceptual framework to infer the origin of water, invertebrates and microbes sampled from boreholes. It demonstrates that pumping 5 m3 at 0.4–1.8 l/sec was sufficient to entrain invertebrates from five to tens of metres into the aquifer during these packer tests. Invertebrates and bacteria were more abundant in the boreholes than in the aquifer, with associated water chemistry variations indicating that boreholes act as sites of enhanced biogeochemical cycling. There was some variability in invertebrate abundance and bacterial community structure between habitats, indicating ecological heterogeneity within the aquifer. However, invertebrates were captured in all aquifer samples, and bacterial abundance, major ion chemistry and dissolved oxygen remained similar. Therefore the study demonstrates that in the Chalk, ecosystems comprising bacteria and invertebrates extend from around the water table to 70 m below it. Hydrogeological techniques provide excellent scope for tackling outstanding questions in groundwater ecology, provided an appropriate conceptual hydrogeological understanding is applied.

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“…More sophisticated methods are urgently needed (Gutjahr et al, 2013;Hancock and Boulton, 2009). Until it is possible to sample at the relevant scales, most theoretical understanding will have to come from modelling (section 4.3).…”

Section: Sampling Micro Scale Variabilitymentioning

confidence: 99%