How freshwater biomonitoring tools vary sub‐seasonally reflects temporary river flow regimes

Characterizing temporary river ecosystem responses to flow regimes is vital for conserving their biodiversity and the services they provide to society. However, freshwater biomonitoring tools rarely reflect community responses to hydrological variations or flow cessation events, and those available have not been widely tested within temporary rivers. This study examines two invertebrate biomonitoring tools characterizing community responses to different flow‐related properties: the “Drought Effect of Habitat Loss on Invertebrates” (DEHLI) and “Lotic‐invertebrate Index for Flow Evaluation” (LIFE), which, respectively reflect community responses to habitat and hydraulic properties associated with changing flow conditions. Sub‐seasonal (monthly) variations of LIFE and DEHLI were explored within two groundwater‐fed intermittent rivers, one dries sporadically (a flashy, karstic hydrology—River Lathkill) and the other dries seasonally (a highly buffered flow regime—South Winterbourne). Biomonitoring tools were highly sensitive to channel drying and also responded to reduced discharges in permanently flowing reaches. Biomonitoring tools captured ecological recovery patterns in the Lathkill following a supra‐seasonal drought. Some unexpected results were observed in the South Winterbourne where LIFE and DEHLI indicated relatively high‐flow conditions despite low discharges occurring during some summer months. This probably reflected macrophyte encroachment, which benefitted certain invertebrates (e.g., marginal‐dwelling taxa) and highlights the importance of considering instream habitat conditions when interpreting flow regime influences on biomonitoring tools. Although LIFE and DEHLI were positively correlated, the latter responded more clearly to drying events, highlighting that communities respond strongly to the disconnection of instream habitats as flows recede. The results highlighted short‐term ecological responses to hydrological variations and the value in adopting sub‐seasonal sampling strategies within temporary rivers. Findings from this study indicate the importance of establishing flow response guilds which group taxa that respond comparably to flow cessation events. Such information could be adopted within biomonitoring practices to better characterize temporary river ecosystem responses to hydrological variations

Molecular Basis of Increased Serum Resistance among Pulmonary Isolates of Non-typeable Haemophilus influenzae

Non-typeable Haemophilus influenzae (NTHi), a common commensal of the human pharynx, is also an opportunistic pathogen if it becomes established in the lower respiratory tract (LRT). In comparison to colonizing isolates from the upper airway, LRT isolates, especially those associated with exacerbations of chronic obstructive pulmonary disease, have increased resistance to the complement- and antibody-dependent, bactericidal effect of serum. To define the molecular basis of this resistance, mutants constructed in a serum resistant strain using the mariner transposon were screened for loss of survival in normal human serum. The loci required for serum resistance contribute to the structure of the exposed surface of the bacterial outer membrane. These included loci involved in biosynthesis of the oligosaccharide component of lipooligosaccharide (LOS), and vacJ, which functions with an ABC transporter encoded by yrb genes in retrograde trafficking of phospholipids from the outer to inner leaflet of the cell envelope. Mutations in vacJ and yrb genes reduced the stability of the outer membrane and were associated with increased cell surface hyrophobicity and phospholipid content. Loss of serum resistance in vacJ and yrb mutants correlated with increased binding of natural immunoglobulin M in serum as well as anti-oligosaccharide mAbs. Expression of vacJ and the yrb genes was positively correlated with serum resistance among clinical isolates. Our findings suggest that NTHi adapts to inflammation encountered during infection of the LRT by modulation of its outer leaflet through increased expression of vacJ and yrb genes to minimize recognition by bactericidal anti-oligosaccharide antibodies

Genome Characterization of the Oleaginous Fungus Mortierella alpina

Mortierella alpina is an oleaginous fungus which can produce lipids accounting for up to 50% of its dry weight in the form of triacylglycerols. It is used commercially for the production of arachidonic acid. Using a combination of high throughput sequencing and lipid profiling, we have assembled the M. alpina genome, mapped its lipogenesis pathway and determined its major lipid species. The 38.38 Mb M. alpina genome shows a high degree of gene duplications. Approximately 50% of its 12,796 gene models, and 60% of genes in the predicted lipogenesis pathway, belong to multigene families. Notably, M. alpina has 18 lipase genes, of which 11 contain the class 2 lipase domain and may share a similar function. M. alpina's fatty acid synthase is a single polypeptide containing all of the catalytic domains required for fatty acid synthesis from acetyl-CoA and malonyl-CoA, whereas in many fungi this enzyme is comprised of two polypeptides. Major lipids were profiled to confirm the products predicted in the lipogenesis pathway. M. alpina produces a complex mixture of glycerolipids, glycerophospholipids and sphingolipids. In contrast, only two major sterol lipids, desmosterol and 24(28)-methylene-cholesterol, were detected. Phylogenetic analysis based on genes involved in lipid metabolism suggests that oleaginous fungi may have acquired their lipogenic capacity during evolution after the divergence of Ascomycota, Basidiomycota, Chytridiomycota and Mucoromycota. Our study provides the first draft genome and comprehensive lipid profile for M. alpina, and lays the foundation for possible genetic engineering of M. alpina to produce higher levels and diverse contents of dietary lipids

Spatial structure in lotic macroinvertebrate communities in England and Wales: relationship with physicochemical and anthropogenic stress variables

We describe the relationship between macroinvertebrate community composition, the physicochemical environment and anthropogenic impacts, in running water sites across a range of water qualities in England and Wales. We have also investigated the degree of spatial structure present in both the macroinvertebrate community and the measured environment. Selected explanatory variables could account for 26% of the variation in lotic macroinvertebrate assemblage composition across England and Wales. The explanatory power of the CCA model was based predominantly on a combination of local scale variables (substrate, alkalinity, urban run-off) and regional scale variables (discharge category, northing). The physicochemical gradient associated with changes in stream type from headwaters to estuary dominated assemblage composition. The influence of pollution and habitat modification were of secondary importance. There was a substantial level of spatial structure to both the physicochemical (47% of its explanatory power spatially structured) and anthropogenic stress data (63% of its explanatory power spatially structured), which resulted in a high level of predictable spatial structuring in macroinvertebrate assemblages. Almost 40% of the variation in assemblage composition accounted for by the explanatory model exhibited spatial structure. Positive spatial autocorrelation in macroinvertebrate community composition extended to sites up to 150 km apart. As a consequence, community composition could be described from northing and easting with 75% of the explanatory power of the eight physicochemical variables. Our study has confirmed the importance of the longitudinal gradient within catchments, as well as the geographical position of the catchment to macroinvertebrate communities. We have also demonstrated how quantifying the spatial structure in the dataset can improve our understanding of the factors influencing macroinvertebrate community structure

Flow regimes control the establishment of invasive crayfish and alter their effects on lotic macroinvertebrate communities

Invasive non-native species (INNS) threaten biodiversity and ecosystem functioning globally. However, there remains a pressing need to understand the environmental factors controlling the dispersal, successful establishment and subsequent ecological impacts of INNS for receiving ecosystems. Here, we examine how region-wide flow regime magnitudes facilitate the successful establishment of an invasive crayfish species (Pacifastacus leniusculus, signal crayfish) in England (UK). We also consider the interactive effects of invasive crayfish with flow regime variations on the structural and functional diversity of macroinvertebrate communities.Low-flow magnitudes increased the likelihood of P. leniusculus establishment, with 80% of recorded invasion dates falling in years with flow magnitudes below average (low- and low-moderate flow classes), whilst only 1.6% occurred in high-flow years.Temporal trajectories of structural and functional macroinvertebrate responses in invaded rivers demonstrated reduced diversity compared to control rivers. Lower taxonomic and functional richness measures typically coincided with periods of low discharge in invaded rivers and were greatest during regionally high-flows.Macroinvertebrate communities displayed significant structural and functional responses to the interaction between invasive crayfish and flow regime variations. Specifically, a number of low- and high-flow indices yielded significant associations, highlighting the role of extreme hydrological events in shaping INNS effects on receiving ecosystems. We also detected greater ecological effects of invasive crayfish under hydrologically stable conditions. Importantly, and for the first time, we observed that invasive crayfish reversed macroinvertebrate community responses to flow regime cues (e.g. discharge fall rate and minimum flows in the preceding 180 days).Synthesis and applications. Results from this study indicate that low-flow events facilitate the spread/establishment of invasive crayfish and correspond with greater ecological effects for receiving ecosystems. Given that low-flow events are predicted to increase in intensity, duration and frequency over the 21st century, our results highlight the potential threat that invasive crayfish may pose under future hydroclimatic changes. Managing river flow regimes effectively (including maintaining higher flow events and flow variability) is likely to be vital in conserving ecological diversity following crayfish invasion.</div

Towards European Inter-Calibration for the Water Framework Directive Procedures and Examples for Different River Types from the BC Project STAR

The book is aimed at illustrating concrete possibilities for comparing and harmonizing the MSs’ classification results by finally setting comparable boundaries to quality classes. The focus is not on intercalibrating biological methods or monitoring systems. The examples of harmonization of the National class boundaries presented here are intended to demonstrate the possibility of identifying and eliminating the possible differences between systems and the potential of using different approaches. The proposed procedure for Inter-calibration consists of two steps: a) comparison of existing National class boundaries; b) harmonization (adjustment) of boundaries. The different procedures were evaluated and tested through an application of datasets provided by STAR partners, other scientific institutions and environment agencies/Environmental Ministries from around Europe. A relevant part of the data presented and processed here was provided as part of the ongoing pilot IC exercises within the various Geographic Inter-calibration Groups’(GIGs). In particular, most test datasets refer to the Central GIG countries and activities, with notable additions from the South of Europe (Mediterranean GIG), where preliminary actions for the pilot started early during 2004 and led to important improvements in the delineation of the Inter-calibration Options.JRC.H.5-Rural, water and ecosystem resource

The use of palaeoecological and contemporary macroinvertebrate community data to characterize riverine reference conditions

Defining reference conditions is a crucial element in quantifying the extent of anthropogenic modification and for identifying restoration targets in riverine ecosystems. Despite palaeoecological approaches being widely applied in lakes to establish reference conditions, their use in lotic ecosystems remains limited. In this study, we examine contemporary, historical (1930 and 1972), and palaeoecological macroinvertebrate biodiversity and biomonitoring scores in Eastburn Beck, a headwater tributary of the River Hull (UK) to determine if palaeoecological approaches can be used to characterize lotic system reference conditions. Palaeoecological samples comprised a greater gamma diversity (18 taxa) than contemporary samples (8 taxa), samples taken in 1972 (11 taxa) and 1930 (8 taxa). Palaeoecological samples supported taxonomically different Gastropoda, Trichoptera, and Coleoptera (GTC) communities compared with contemporary and historical samples (1930 and 1972). Results from biomonitoring indices using the GTC community indicated that the palaeochannel had (a) similar invertebrate biological quality, (b) a less energetic flow regime, and (c) increased fine sediment deposits compared with the contemporary channel. The results clearly illustrate that palaeoecological data can provide a suitable method to characterize reference conditions for lotic habitats. However, it is important to recognize that faunal data from palaeochannel deposits provide a short-term “snapshot” of the conditions within the river immediately prior to its hydrological isolation. River restoration activities should therefore draw on multiple lines of evidence, including palaeoecological information where possible, to characterize a range of reference conditions to reflect the highly dynamic nature of lotic ecosystems