Using boreholes as windows into groundwater ecosystems.

Bibliographic Details
Title: Using boreholes as windows into groundwater ecosystems.
Authors: James P R Sorensen, Louise Maurice, François K Edwards, Daniel J Lapworth, Daniel S Read, Debbie Allen, Andrew S Butcher, Lindsay K Newbold, Barry R Townsend, Peter J Williams
Source: PLoS ONE, Vol 8, Iss 7, p e70264 (2013)
Publisher Information: Public Library of Science (PLoS), 2013.
Publication Year: 2013
Collection: LCC:Medicine
LCC:Science
Subject Terms: Medicine, Science
More Details: 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 m(3) 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.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1932-6203
Relation: http://europepmc.org/articles/PMC3729555?pdf=render; https://doaj.org/toc/1932-6203
DOI: 10.1371/journal.pone.0070264
Access URL: https://doaj.org/article/01d5ab4a7c7c455c8b0919033d30b89f
Accession Number: edsdoj.01d5ab4a7c7c455c8b0919033d30b89f
Database: Directory of Open Access Journals
More Details
ISSN:19326203
DOI:10.1371/journal.pone.0070264
Published in:PLoS ONE
Language:English