British Freshwater Research Articles

Anthropogenic Drivers of Variation in Concentrations of Perfluoroalkyl Substances in Otters (Lutra lutra) from England and Wales.

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous environmental contaminants that have been linked to adverse health effects in wildlife and humans. Here, we report the presence of PFASs in Eurasian otters (Lutra lutra) in England and Wales and their association with anthropogenic sources. The following 15 compounds were analyzed: 10 perfluoroalkyl carboxylic acids (PFCAs), 4 perfluoroalkyl sulfonic acids (PFSAs), and perfluorooctane sulfonamide, in livers of 50 otters which died between 2007 and 2009. PFASs were detected in all otters analyzed, with 12/15 compounds detected in ≥80% of otters. Perfluorooctane sulfonate (PFOS) accounted for 75% of the ΣPFAS profile, with a maximum concentration of 6800 μg/kg wet weight (ww). Long-chain (≥C8) PFCAs accounted for 99.9% of the ΣPFCA profile, with perfluorodecanoic acid and perfluorononanoic acid having the highest maxima (369 μg/kg ww and 170 μg/kg ww, respectively). Perfluorooctanoic acid (PFOA) concentrations were negatively associated with the distance from a factory that used PFOA in polytetrafluoroethylene manufacture. Most PFAS concentrations in otters were positively associated with load entering wastewater treatment works (WWTW) and with arable land, suggesting that WWTW effluent and sewage sludge-amended soils are significant pathways of PFASs into freshwaters. Our results reveal the widespread pollution of British freshwaters with PFASs and demonstrate the utility of otters as effective sentinels for spatial variation in PFAS concentrations.

Complex and divergent histories gave rise to genome-wide divergence patterns amongst European whitefish (Coregonus lavaretus).

Pleistocene glaciations dramatically affected species distribution in regions that were impacted by ice cover and subsequent postglacial range expansion impacted contemporary biodiversity in complex ways. The European whitefish, Coregonus lavaretus, is a widely distributed salmonid fish species on mainland Europe, but in Britain it has only seven native populations, all of which are found on the western extremes of the island. The origins and colonization routes of the species into Britain are unknown but likely contributed to contemporary genetic patterns and regional uniqueness. Here, we used up to 25,751 genome‐wide polymorphic loci to reconstruct the history and to discern the demographic and evolutionary forces underpinning divergence between British populations. Overall, we found lower genetic diversity in Scottish populations but high differentiation (F ST = 0.433–0.712) from the English/Welsh and other European populations. Differentiation was elevated genome‐wide rather than in particular genomic regions. Demographic modelling supported a postglacial colonization into western Scotland from northern refugia and a separate colonization route for the English/Welsh populations from southern refugia, with these two groups having been separated for more than ca. 50 Ky. We found cyto‐nuclear discordance at a European scale, with the Scottish populations clustering closely with Baltic population in the mtDNA analysis but not in the nuclear data, and with the Norwegian and Alpine populations displaying the same mtDNA haplotype but being distantly related in the nuclear tree. These findings suggest that neutral processes, primarily drift and regionally distinct pre‐glacial evolutionary histories, are important drivers of genomic divergence in British populations of European whitefish. This sheds new light on the establishment of the native British freshwater fauna after the last glacial maximum.

Predatory impacts of the invasive ‘killer shrimp’ Dikerogammarus villosus on a resident amphipod and isopod (Crustacea: Malacostraca) are influenced by water quality and habitat type

The Ponto-Caspian amphipod Dikerogammarus villosus has invaded Central European and British freshwaters and its arrival is associated with biodiversity decline, as D. villosus is predatory towards many macroinvertebrate taxa, including resident amphipods such as Crangonyx pseudogracilis and isopods such as Asellus aquaticus. I investigated how differential physiological tolerance, habitat use and predation may drive coexistence or exclusion among D. villosus and resident ‘supertramp’ prey such as C. pseudogracilis. Experiments revealed that D. villosus could not survive 12 h in the extremely poor water qualities that C. pseudogracilis and A. aquaticus commonly live. Experiments manipulating oxygen levels, revealed low survivorship of C. pseudogracilis and A. aquaticus in the presence of D. villosus at higher oxygen levels but this survivorship increased significantly as oxygen levels fell. Predation of C. pseudogracilis by a resident amphipod Gammarus pulex followed a similar pattern but was much less severe and A. aquaticus appeared resistant to G. pulex predation. Mesocosm experiments showed that C. pseudogracilis survivorship in the presence of D. villosus increased when dense vegetation was present compared to bare substrate. Survivorship of A. aquaticus was uniformly poor in all habitats. Taxa with high environmental tolerance and adaptability may be resistant to this invader’s worst impacts.

The Differential Warming Response of Britain's Rivers (1982-2011).

River water temperature is a hydrological feature primarily controlled by topographical, meteorological, climatological, and anthropogenic factors. For Britain, the study of freshwater temperatures has focussed mainly on observations made in England and Wales; similar comprehensive data sets for Scotland are currently unavailable. Here we present a model for the whole of mainland Britain over three recent decades (1982–2011) that incorporates geographical extrapolation to Scotland. The model estimates daily mean freshwater temperature for every river segment and for any day in the studied period, based upon physico-geographical features, daily mean air and sea temperatures, and available freshwater temperature measurements. We also extrapolate the model temporally to predict future warming of Britain’s rivers given current observed trends. Our results highlight the spatial and temporal diversity of British freshwater temperatures and warming rates. Over the studied period, Britain’s rivers had a mean temperature of 9.84°C and experienced a mean warming of +0.22°C per decade, with lower rates for segments near lakes and in coastal regions. Model results indicate April as the fastest-warming month (+0.63°C per decade on average), and show that most rivers spend on average ever more days of the year at temperatures exceeding 10°C, a critical threshold for several fish pathogens. Our results also identify exceptional warming in parts of the Scottish Highlands (in April and September) and pervasive cooling episodes, in December throughout Britain and in July in the southwest of England (in Wales, Cornwall, Devon, and Dorset). This regional heterogeneity in rates of change has ramifications for current and future water quality, aquatic ecosystems, as well as for the spread of waterborne diseases.

Thermal refugia and the survival of species in changing environments: new evidence from a nationally extinct freshwater fish.

AbstractVariation in global climate during the Quaternary has helped shape current species distributions. The stenohaline fish fauna of the British Isles is generally thought to have colonised eastern England via a landbridge following the last glacial maximum. This theory is investigated using the nationally extinct burbot, Lota lota, as a model species. Samples were collected from 15 museum specimens of known English provenance and analysed for differences in the mitochondrial DNA control region. The DNA analysis produced eight sequences of 270 base pairs, with one sample reaching 420 base pairs in length. Genetic analysis suggests the extinct English population of the burbot was a distinct lineage, differing from those previously described from across the species’ global distribution. Despite this, network analysis suggests that the English lineage is closely related to populations in western Europe, supporting colonisation via a postglacial landbridge. The rate of genetic divergence suggests that the timing of L. lota's colonisation of English rivers was prior to the last glacial maximum. Lota lota appears to have survived the last glacial maximum in refugia within the British Isles. This study adds to the evidence for a British freshwater refugia and furthers our understanding of the colonisation history of British freshwater fishes. These results also provide valuable information for conservation strategies for L. lota indicating the western European clade as most genetically appropriate for potential future reintroductions to English rivers.

“The pump don’t work, ‘Cause the vandals took the handles”; why invasive amphipods threaten accurate freshwater biological water quality monitoring

The 2010 invasion of Great Britain by the eastern European ‘killer shrimp’ Dikerogammarus villosus (Crustacea: Amphipoda) was just the latest of several amphipod invasions of British freshwaters and just one of many amphipod invasions occurring on a global scale. Using examples of previous invasions of other amphipods, Gammarus pulex and Crangonyx pseudogracilis in The Isle of Man and Northern Ireland, I show that these invaders have the potential to undermine the accuracy of ecological assessment programmes of freshwater, such as those employed in the Water Framework directive (WFD) in Europe and similar schemes used by environmental protection agencies all over the world. Such assessment programmes invariably rely on biological water quality monitoring using biotic indices derived from resident macroinvertebrate assemblages. All three amphipod invaders can greatly undermine accurate water quality biomonitoring in river systems. This can be by invasive amphipods predating upon and/or outcompeting resident macroinvertebrates and thus radically altering resident biodiversity and assemblage structure. This can also occur because these invaders tend to be more physico-chemically tolerant than the resident taxa they are replacing and this greater tolerance of poor organic chemical water quality is not acknowledged in biotic scoring indices. A way forward would be to measure the biological pressure invaders may exert in a biocontamination index or similar, while simultaneously carrying out routine water quality monitoring using biotic indices.

The zebra mussel (Dreissena polymorpha) impacts European bitterling (Rhodeus amarus) load in a host freshwater mussel (Unio pictorum)

The European bitterling, Rhodeus amarus, is a non-indigenous fish species in British fresh waters. It lays its eggs in unionid mussels which themselves are vulnerable to fouling by the non-indigenous zebra mussel, Dreissena polymorpha. Observations from an unmanipulated natural system showed that only 27% of zebra mussel-fouled Unio pictorum hosted bitterling, while 47% of unfouled U. pictorum hosted bitterling. We conducted a field experiment in the River Great Ouse catchment, Cambridgeshire, England in May–June 2007 and 2008 to quantify the impact of zebra mussels on bitterling load in host mussels. Zebra mussel-fouled unionids were significantly less likely to host bitterling than unfouled unionids. The number of unionids hosting bitterling did not differ significantly whether the zebra mussels fouling the unionid were alive or dead. Bitterling appeared to discriminate against zebra mussel-fouled unionids less as the 2007 breeding season advanced, potentially because preferred unfouled unionids had a higher bitterling load, and were therefore relatively lower quality hosts than at the start of the breeding season.

The development of bird indicators for British fresh waters and wetlands

1. Population trends of breeding birds in freshwater habitats generated from long-term monitoring in the UK provide biodiversity indicators for some wetland habitats. 2. Bird species were assigned to target wetland habitats based on evidence of their association and data availability. Species trends for each habitat were then modelled using a range of survey data from BTO schemes including the Common Bird Census, Breeding Bird Survey, Waterways Bird Survey and Waterways Breeding Bird Survey. 3. Smoothed population trends for the selected species were combined to produce a composite indicator for birds of selected waterways and wetland habitats for England. This forms one of the three strands of a new aggregate bird indicator in the UK. 4. These indicators show generally that breeding bird species associated with slow-moving waterways and standing waters have increased over the past 30 years. Over the same period, species associated with fast-flowing waters show modest declines, species associated with reed habitats have declined and recovered, while species associated with wet grasslands, including marshes, have declined. 5. Further monitoring and exploration of the relationship between these indicators is needed to improve confidence in species trends and identifying potential drivers of change in freshwater and wetland habitats. Copyright © 2009 John Wiley & Sons, Ltd.

Organic and siliceous protistan scales in north-east Atlantic abyssal sediments

We report the occurrence of a high diversity of minute (∼1 μm diameter) organic and siliceous protistan scales in small samples (total volume ∼35 μl) of superficial sediment from the Porcupine Abyssal Plain (PAP), north-east Atlantic (4850 m water depth). Many exhibit characters by which they can be identified to species. The organic scales belong to the haptophyte genera Chrysochromulina (8–9 species), Chrysocampanula and Dolichomastix (1 species each). The siliceous scales belong to the chrysophytes Paraphysomonas vestita and Meringosphaera sp. and to the heterotrophic flagellate genus Thaumatomastix (T. dybsoeana, T. formosa, Thaumatomastix sp.). As far as we are aware, this is the first time that non-calcareous protistan scales have been observed in deep-sea sediments (although siliceous skeletal plates and cysts are reported). All scales probably originated from the upper water column and were delivered to the deep-sea floor on rapidly sinking detrital aggregates. However, naked heterotrophic flagellates are known to thrive in abyssal sediment habitats and so the possibility that some scale-bearing protists also live in benthic deep-sea environments cannot be eliminated. Many species identified at the PAP site are common in coastal marine waters around Europe; some occur as far afield as Tasmania and New Zealand. Five Chrysochromulina species are known from central oceanic areas, including parts of the North Atlantic, while another species, C. pringsheimii, is reported from a British freshwater lake. We retrieved ∼15% of the 55 named Chrysochromulina species (∼8% of the estimated total number of species in this diverse group) in the ∼35 μl of abyssal sediment. Because the scales can persist and be identified after cell death, they may provide useful time- and space-averaged information about the distribution of protist species in marine habitats. The long-term fate of the scales on the sea-floor is unknown. It is possible that at least some of the organic scales are preserved as microfossils in deep-sea sediments.

Range size and environmental calcium requirements of British freshwater gastropods

ABSTRACTCalcium is an essential requirement for the successful growth and development of gastropod molluscs. Data for British freshwater gastropods were used to examine the relationship between environmental calcium requirements and British and European range sizes. At both spatial scales calciphile species, which require a high level of environmental calcium, had significantly smaller range sizes than species able to exploit a wide range of environmental calcium levels. However, at least in Britain, range size may also be influenced by the availability of suitable habitat. British and European range sizes were significantly correlated. This study provides evidence for niche‐based explanations of range size variation, and suggests that both niche breadth and niche availability are important in determining range size.

Assessing the Impacts of International Emissions Reduction Scenarios on the Acidification of Freshwaters in Great Britain with the First-Order Acidity Balance (FAB) Model and the Hull Acid Rain Model (HARM)

Critical loads models for acidity underpin international negotiations for the reduction of acid deposition through emissions controls. In Great Britain and Scandinavia, critical loads for freshwater ecosystems are calculated with the First-order Acidity Balance (FAB) model, which can provide a catchment based estimate of deposition reduction requirements of sulphur and nitrogen species in order to protect any aquatic target organism for which a critical chemical threshold is defined. The FAB model is applied to a national freshwaters database for Great Britain using three deposition scenarios generated with the Hull Acid Rain Model (HARM). Critical load exceedance and changes in three important chemical indicators (non-marine sulphate, nitrate and acid neutralising capacity) are assessed for 1990 baseline deposition levels, planned emissions reductions under existing international commitments (REF scenario), and a potential stringent emission reduction scenario under a multi-pollutant, multi-effect strategy (E10 scenario). Model outputs indicate that the number of sampled sites exceeding their critical load would be reduced by 60% and 73% respectively under the two future deposition scenarios. There is a clear need for a strategy to reduce both S and N deposition from 1990 levels if British freshwaters in sensitive areas are to be protected.

Monobothrium wageneri: another imported tapeworm established in wild British freshwater fishes?

The caryophyllidean monozoic tapeworm Monobothrium wageneri is recorded for the first time in the U.K. in tench Tinca tinca from four different sites in S.E. England. The likelihood that this is an exotic import is discussed. It is considered that the weight of evidence indicates that it has been introduced into the U.K. probably in ornamental tench.

Monobothrium wageneri: another imported tapeworm established in wild British freshwater fishes?

Monobothrium wageneri: another imported tapeworm established in wild British freshwater fishes?

Organochlorine pesticide residues and PCBs in eels ( [formula omitted]) from some British freshwater reedbeds

Organochlorine pesticide residues and PCBs were measured in bulked samples of whole eels collected in 1991 from 11 reedbed sites of wildlife conservation importance in Britain. Eels from some sites had only trace amounts of dieldrin, p,p-DDE and PCBs. Maximum concentrations were 0.21 mg kg −1 for dieldrin, 0.27 mg kg −1 for p,p-DDE and 0.91mg kg −1 for PCBs (fresh weight). Concentrations of contaminants in eels from reedbeds were considered in general to be lower than in eels from rivers, but nevertheless concentrations were considered to be sufficiently high at some sites to adversely affect top carnivores such as the otter.

The Freshwater Biological Association

Describes the history of the Freshwater Biological Association and its Library. Notes that the library produces a current awareness bulletin listing over 750 freshwater ecology papers each month, an annual bibliography of papers on British freshwaters and undertakes manual and on‐line retrospective information enquiries. Concludes that these flexible national and international networks of information exchange and collaboration survive despite an ever changing spectrum of political philosophies.

Afforestation, soil erosion and sediment yields in British fresh waters

Afforestation, soil erosion and sediment yields in British fresh waters

Production, detection, and quantification of cyanobacterial toxins

AbstractCyanobacterial blooms from several British freshwaters have been toxic by mouse bioassay each year since annual sampling began in 1981. Toxic blooms of Microcystis aeruginosa, Anabaena spp., Gloeotrichia echinulata, Oscillatoria spp., and Aphanizomenon flos‐aquae occur, with peptide toxin‐producing Microcystis and Anabaena being most often encountered. We are developing a range of detection and quantification methods for cyanobacterial peptide and alkaloid toxins to supplement the standard mouse bioassay. Both types of toxins can be readily assayed by high performance liquid chromatography, and we have developed facile high performance thin layer chromatographic procedures for their detection from natural blooms and laboratory cultures. We have also produced polyclonal and monoclonal antibodies for the assay of Microcystis toxins by enzyme‐linked immunosorbent assay and have developed in vitro fibroblast cytotoxicity assays for the toxins of Microcystis and other cyanobacteria.

Afforestation and sediment yields in British fresh waters

Abstract. This paper reviews research on sediment yields in British fresh waters affected by afforestation in their catchments. Soil erosion and sedimentation in fresh waters increase after afforestation in the uplands. In the long term a three‐to tour‐fold increase appears to be common in established upland forests, but much larger increases, some amounting to 50 times that before afforestation, have been recorded soon after ploughing, draining, roadmaking and harvesting. Some of the erosion has been exacerbated by environmental conditions such as steep slopes and storms. Improved silvicultural practices should reduce sediment output to fresh waters, but they might not prevent serious sedimentation following afforestation in the uplands. In contrast, afforestation of arable land under the Farm Woodland Scheme should result in decreased rates of erosion in the lowlands.

Scale surface micro-structures of British freshwater cyprinidae

The scales of the roach ( Rutilus rutilus L.), rudd ( Scardinus erythropthalmus L.) and Crucian carp ( Carassius carassius L.) Cyprinidae, Teleostei, were examined by scanning electron microscopy. The circuli in the overlapped areas of the scales were found to be denticulated. Inter-specific variation of denticular morphology, height and spacing was revealed when circuli of comparable ontogenetic age were investigated. The osseus material forming the circuli is reduced in thickness or absent at the scale radii. On the basis of the results of this study it is considered that the term micro-structure should be used in preference to ‘ornamentation’ to describe scale surface characteristics.

The chemical ecology of some British freshwater gastropod molluses: behavioural responses to short chain carboxylic acids and maltose

SUMMARY. 1. The behavioural responses of six species of British freshwater gastropods to chemical gradients of short chain carboxylic acids (C‐2 to C‐5, C‐8) and maltose were investigated by means of diffusion olfactometers.2. The species were ranked as follows on the basis of the number of significant behavioural responses to the test chemicals: Lymnaea peregra > Planorbis contortus > Physa fontinalis > Planorbis planorbis > Bithynia tentaculata > Planorbis vortex. These differences were not a result of differences in activity but reflect real differences in ehemoreception.3. Propanoate (C‐3) was a significant attractant or arrestant to five snail species, C‐4, C‐8 and maltose to four species and C‐5 to three species. Acetate (C‐2) was a significant attractant to L. peregra and P. fontinalis but it was the only acid to act as a repellent, to P. planorbis and B. tentaculata.4. Lymnaea peregra continued to respond to repeated butanoate application. Response levels could be enhanced by increasing concentration (minimum thresholds 10‐4M to 10−5 M), pH (above 6) and food deprivation.5. The ecological relevance of the results are discussed with particular reference to the distributional patterns of the chemicals and snails and the feeding niches of the latter.