SUMMARY1. Classification of groundwater habitats and communities at different spatial scales is emphasised as a basic requirement for the implementation of groundwater ecology into legislation. Such a classification would also facilitate prediction of groundwater biodiversity, abundance and community structure, but is not currently available. 2. To identify the factors influencing the distribution of stygofauna at the landscape scale, the groundwater fauna of Baden-Wü rttemberg in South-western Germany was sampled from November 2001 to December 2002. A total of 304 boreholes were sampled twice with a phreatic net. Boreholes were originally selected to represent the full range of geographic, geological and hydrographic variation within the sampling area. However, bores in porous aquifers were overrepresented because the monitoring networks that could be used in this study were originally designed for hydrogeological purposes. 3. In total, 105 taxa (including 60 stygobionts) were found. Most of the stygobionts were rare, with 52% of them occurring in less than 1% of the boreholes. Stygobiotic taxonomic richness in a region or so-called geological unit was directly correlated with the number of bores sampled. Species richness accumulation curves indicated that the real taxonomic richness of Baden-Wü rttemberg is considerably higher than the recorded number of 60 stygobiotic taxa. This finding is in accordance with studies from other regions and suggests that groundwater biodiversity generally is strongly underestimated, probably resulting mainly from huge heterogeneity of groundwater systems and reliance on broad-scale hydrological monitoring networks. 4. To identify regional distribution patterns, the sampling area was separated into regional geological units, each comprising all aquifers of identical geology in a particular region (size: hundred to several thousand square kilometres). Distribution patterns of the aquatic subterranean fauna (including non-stygobionts) were found to be influenced to some degree by the geographical position of the bores, and to a large extent by hydrogeological aquifer type rather than by affiliation of aquifers to a given geological unit. Four types of aquifers could be distinguished: Compact aquifers (aquitards) with reduced pore spaces, and porous, fractured and karstic aquifers. 5. Communities of porous and karstic aquifers were found to be more similar to each other than the communities of compact and fractured aquifers. Therefore, for the purpose of recording groundwater biodiversity and defining undisturbed groundwater habitats, we suggest focusing more strongly than in the past on aquifer hydraulic conductivity and, in particular, on compact and fractured aquifers.

No abstract

No abstract

BackgroundShort stems have gained popularity in recent years. Because of encouraging clinical results, indications have been expended from young to elderly and obese patients. However, long-term results are lacking. The purpose of this study was to evaluate the influence of gender, age, body weight, body mass index (BMI), and offset version on short-stem migration in correlation to the clinical outcome.MethodsThe implant migration of 202 metaphyseal-anchoring, calcar-guided short stems in 151 patients was assessed by “Einzel-Bild-Roentgen-Analyse” femoral component analysis (EBRA-FCA, femoral component analysis) in a 2-year follow-up. Full weight bearing was allowed directly after surgery. Patients were divided into groups regarding gender, age, body weight, BMI, and offset version. The Harris hip score (HHS) and satisfaction on visual analogue scale (VAS) were analyzed.ResultsAfter 2 years, mean axial subsidence of all 202 implants was 1.43 mm (standard deviation, SD 1.45 mm). A continuous reduction of initially pronounced subsidence over time could be observed. None of the stems had to be revised. Statistically significant increased rates of subsidence were seen in male (1.68 mm; SD 1.56 mm; p = 0.005) and heavy patients (1.54 mm; SD 1.48 mm; p = 0.022). No differences in implant migration were found regarding age, BMI, and different offset versions. HHS improved markedly from 45.8 (SD 15.9) to 98.1 (SD 4.7) while satisfaction on VAS improved from 1.8 (SD 2.2) to 9.7 (SD 0.9) after 2 years.ConclusionsThe results suggest a migration pattern with initially pronounced subsidence followed by subsequent stabilization. Male and obese patients show a slightly increased initial subsidence without any signs of sustained micromovement. No correlation was found concerning clinical results and pronounced initial subsidence above the threshold of 1.5 mm. No aseptic loosening or other signs of implant failure were seen within the observation period of 2 years.Trial registrationGerman Clinical Trials Register, DRKS00009834.

The use of ecological criteria for the assessment of aquatic ecosystem status is routine for surface waters. So far no ecological parameters are considered for the assessment and monitoring of groundwater quality. It has been well known for decades that aquifers are ecosystems harbouring a vast diversity of invertebrates and microorganisms. The growing knowledge on groundwater microbial and faunal communities as well as the molecular and statistical tools available form a solid ground for the development of first ecologically sound assessment schemes. The sensitivity of groundwater communities towards impacts from land use and surface waters is exemplarily demonstrated by a data set of two geologically similar but hydrologically partially separated aquifer systems. Subgroups of the fauna in groundwater (stygobites vs. stygophiles and stygoxenes) successfully indicated elevated nitrate impacts linked to land use activities. Within the microbial communities, impacts from land use are mirrored by high bacterial biodiversity values atypical for pristine groundwater of comparable systems. The data show that there is legitimate hope for the application of ecological criteria for groundwater quality assessment in the future.