1. Groundwater ecosystems
Research from England
Tim Besien and Tim Johns
5 October 2015

2. Talk summary Why? Species & communities Distribution & drivers
Habitat preferences
Food webs
Hypogean Crustacea Recording Scheme

3. Why?
Recital 20 in the Groundwater Directive 2006

4. Species & communities
Only 8 species of GW macro Crustacea reported in England
These are obligate GW animals termed - stygobites
Majority limited to southern England – glacial legacy?
Niphargus glenniei – endemic to SW England
Microniphargus leruthi – first record in England 2010
Hypogean Custacea Recording Scheme (Lee Knight)
Photo by Chris Proctor
Environment Agency
N glenniei,
UK Biological Action
Plan species
Robertson, A. L., et al. "The distribution and diversity of stygobites in Great Britain: an analysis to inform groundwater management." Quarterly Journal of Engineering Geology and Hydrogeology 42.3 (2009):

5. Molecular study – interesting!
UK Niphargid populations have a distinct lineage
Divergence from continental Europe
N. kochianus 2.9 Ma
N. aquilex Ma
N. fontanus 0.8 Ma
N. glenniei, the most ancient endemic British fauna, 19.5Ma
Important biodiversity element, resilience to climate change BUT vulnerable to other human pressures
McInerney et al., Molecular Ecology
McInerney, Caitríona E., et al. "The ancient Britons: groundwater fauna survived extreme climate change over tens of millions of years across NW Europe." Molecular ecology 23.5 (2014):

6. Regional-scale drivers
Study of ~200 wells & BHs in SW England – presence/absence & abundance of species recorded with geology and WQ data
GW fauna recorded in all geological ‘hydro-units’ examined BUT significantly more likely in carbonate & igneous/metamorphic rocks than mudstones and sandstones
CCA & variance portioning indicated geology (hydro-units) relatively more important than WQ in explaining GW community observed.
Distinct distribution of species observed – geological barrier may explain this & absence of N. glenniei west of Devon
Johns et al, 2014 Regional-scale drivers of groundwater faunal distributions
Johns, Tim, et al. "Regional-scale drivers of groundwater faunal distributions."Freshwater Science 34.1 (2015):

7. Invertebrate fauna of Chalk GW
Samples from BHs in Chalk – recovered using a plankton net
Stygobites present in ~ 70 % BHs. N. kochinanus most common species recorded
GW fauna present in deep & shallow BHs (100m BGL & at least 70m BWT)
No stygobites recorded from confined Chalk (limited samples)
Maurice et al (in press) The invertebrate ecology of Chalk groundwater
Maurice et al (in press) The invertebrate ecology of Chalk groundwater, Hydrogeology Journal

8. The Chalk habitat
Packer tests on 3 fractures identified in chalk BH in southern England
5000 litres (2l/s) - water chemistry tested & fauna recovered
Water chemistry remained similar, GW fauna ubiquitous
Suggests suitable habitat but population estimations difficult
CCTV used to provide supporting evidence
82m bgl
Sorensen et al , Using boreholes as windows into groundwater ecosystems
Sorensen, James PR, et al. "Using boreholes as windows into groundwater ecosystems." PloS one 8.7 (2013): e70264.

9. Ecology studies
Hypogean Crustacea Recording Scheme
Few studies on auto-ecology of Niphargus species in Britain
Phototactic & temperature responses investigated for N aquilex & N glenniei in experimental aquarium in a Devon cave
Both species tolerant to wide temperature range (1-26oc). Entered torpor ~2-4oc
Negative phototactic response suggested by other studies not obvious, N aquilex showed weak response, most strongly to UV light
Study supported by grant from British Cave Research Association
Knight Lee RFD & Johns T “Auto-ecological studies on Niphargus aquilex (Schiödte, 1855) and Niphargus glenniei (Spooner, 1952) (Crustacea: Amphipoda: Niphargidae)” Cave & Karst Science 42.2(2015):63-77

10. GW community response to flooding
Tracked changes in GW community (bacterial, protozoan, micrometazoan & macrofauna) following significant flooding event (2014)
Two spatially separated chalk aquifers, 4 BHs in each, sampled every 2 weeks for 7 months
DOC concentrations & bacterial abundance – higher just after recharge event, then declined
Macrofaunal abundance increased with time but biomass lower (more juvenilies)
GW communities showed strong size structure, indicative of stable environment
Robertson et al (in preparation) Groundwater Flooding: groundwater community recovery following an extreme recharge event.

11. Groundwater food webs – ongoing PhD
Dissolved Organic Carbon (DOC)
Particulate Organic Matter (POM)
Bacteria
Protozoa (e.g. ciliates, flagellates, amoebae)
Meiofauna (e.g. copepods, nematodes)
Macrofauna (e.g. crustaceans, cave fish)
Low complexity, truncated ecosystems
Stygobites are top level predators
Effects of these predators on protozoans have not been explored to date
Ideal for study of example ecological networks – focus of current PhD
Flow of Energy / Biomass through trophic levels
Return of Energy / Biomass through bacterial degradation of all trophic levels
Weitowitz, D.; Reiss, J.; Robertson, A. University of Roehampton

12. Summary UK is working on the research requirements set out in the GWD
Still lots of unknowns
Further work needed, particularly on the impacts of anthropogenic pressures
Research networks - Paul Wood, Loughborough University has set up an EU-wide group to seek consensus on research directions

13. Key contributors to recent studies
Lee Knight – Hypogean Crustacea Recording Scheme (UK) Tim Johns – Environment Agency Anne Robertson – Roehampton University Damiano Weitowitz – Roehampton University Lou Maurice – British Geological Survey Paul Wood – Loughborough University Bernd Hänfling – Hull Univeristy Caitriona McInerney – Hull University
Studies listed