Mission possible: diatoms can be used to infer past duckweed (lemnoid Araceae) dominance in ponds

Compared to larger lakes, ponds have rarely been the focus of palaeoecological studies. A common feature of ponds, especially those subject to eutrophication, is mass surface coverings of lemnoid Araceae (duckweed) which have severe implications for ecological processes in small waterbodies, in particular lowered oxygen content. To help understand the implications of duckweed dominance for the long-term ecology of ponds, and to determine the potential for palaeoecological studies in ponds more generally, we develop a new diatom-based Lemna-indicator metric. Recent studies of diatom host-plant relationships have shown significant associations between duckweed and the epiphytes Lemnicola hungarica and Sellaphora saugerresii (formally known as Sellaphora seminulum). To determine the potential of these species as palaeo-indicators of long-term duckweed dynamics in ponds, we investigated the diatom composition of surface sediment assemblages in sets of duckweed and non-duckweed-dominated ponds in Norfolk, eastern England. In addition, we undertook diatom analysis of two cores from a small farmland pond (Bodham Rail Pit) subject to a known duckweed dominance event (1999–2005). Both L. hungarica and S. saugerresii were significant predictors of past Lemna dominance in the surface sediments. Further, in the core study, both diatom species accurately and closely tracked the documented “on–off” duckweed cycle. Our study suggests huge potential for using ponds in palaeoecological studies and for diatom-based investigations of floating plant histories

The ‘Pritchard Trap’: a novel quantitative survey method for crayfish

1. As crayfish invasions continue to threaten native freshwater biota, a detailed understanding of crayfish distribution and population structure becomes imperative. Nonetheless, most current survey methods provide inadequate demographic data. The quantitative ‘Triple Drawdown’ (TDD) dewatering method has highlighted the importance of such data, yet practical constraints prevent its large-scale application. 2. Here, we introduce the ‘Pritchard Trap’, a novel passive sampling method that reliably generates quantitative crayfish population data while requiring substantially lower sampling effort than TDDs. This quadrat-style sampler was extensively tested in headwater streams of North Yorkshire, England, along an invasion gradient for signal crayfish (Pacifastacus leniusculus) from well-established sites to mixed populations of signal crayfish and native white-clawed crayfish (Austropotamobius pallipes). 3. The Pritchard Trap was trialled over several time intervals to determine the minimum required trap deployment time. TDDs at the same sites allowed for a robust evaluation of Pritchard Trap sampling accuracy in representing crayfish densities and population structure. 4. The Pritchard Trap successfully sampled both invasive and native crayfish (8–42 mm carapace length). A minimum passive deployment time of 4 days was required. At low crayfish densities (0.5 individuals m−2), increased trapping effort was necessary to achieve accurate population density and size class distribution estimates. The Pritchard Trap required substantially less sampling effort (working hours) and resources than the TDD, whilst also posing less risk to non-target species. 5. The Pritchard Trap, for the first time, affords logistically simple, truly quantitative investigations of crayfish population demographics for headwater systems. It could be integrated into crayfish research and management, for example to explore density-dependent ecological impacts of invasive crayfish and their management responses or to monitor populations and recruitment in native crayfish conservation initiatives

Recent heavy metal contamination of the Thurne Broads

The banning of tributyltin (TBT) from boat antifouling paints in the late 1980s led to its replacement by alternative biocide additives (Voulvoulis et al., 2000; Marcheselli et al., 2010), including Cu (Dahl & Blanck, 1996) and Zn as active ingredients. It has been reported that Cu and Zn compounds associated with these biocides have caused substantial contamination of harbour and marina sediments (Eklund et al., 2010; Parks et al., 2010), with negative toxic consequences for aquatic organisms (Ytreberg et al., 2010). Indeed, it is evident that Cu and Zn compounds present in paint fragments are readily leached into the water column allowing entry into aquatic food webs (Jessop & Turner, 2011). Nevertheless, relatively little is known regarding antifoulant-derived metals contamination in freshwater lakes. The Norfolk and Suffolk Broads (Eastern England, UK) have been contaminated by antifoulant-derived heavy metals, particularly Cu and Zn which have increased since the banning of TBT (post-1987) in parts of the boated system (Boyle et al., in prep.). Further, recent studies suggest that current levels of sediment contamination by Cu may have negative ecological effects for aquatic ecosystems including inhibition of aquatic macrophyte germination and performance (Boyle et al., submitted; S. Lambert, unpublished data). In Hickling Broad (Thurne Broads system), post-TBT increases in Cu and Zn are also evident, with an interesting peak in Cu for the late 1990s in core HICK1 (Figure 1). This coincides with the large-scale loss of aquatic macrophytes (especially Characeae) from the lake in 1999 (Barker et al., 2008). HICK1 was collected in 2003. In the proposed study we sought to gain a fuller understanding of recent metal contamination in Hickling Broad up to the present day, whilst looking to verify and better contextualise the late 1990s Cu peak. Further, we aimed to determine whether the peak in Cu for Hickling Broad was also recorded at Horsey Mere which is used as a control site in this study i.e. is it just a Hickling phenomenon? Or is it a Thurne Broads system-wide effect

Palliative care specialists' perceptions concerning referral of haematology patients to their services : findings from a qualitative study

Background: Haematological malignancies (leukaemias, lymphomas and myeloma) are complex cancers that are relatively common, affect all ages and have divergent outcomes. Although the symptom burden of these diseases is comparable to other cancers, patients do not access specialist palliative care (SPC) services as often as those with other cancers. To determine the reasons for this, we asked SPC practitioners about their perspectives regarding the barriers and facilitators influencing haematology patient referrals. Methods: We conducted a qualitative study, set within the United Kingdom’s (UK’s) Haematological Malignancy Research Network (HMRN: www.hmrn.org), a population-based cohort in the North of England. In-depth, semistructured interviews were conducted with 20 SPC doctors and nurses working in hospital, community and hospice settings between 2012 and 2014. Interviews were digitally audio-recorded, transcribed and analysed for thematic content using the ‘Framework’ method. Results: Study participants identified a range of barriers and facilitators influencing the referral of patients with haematological malignancies to SPC services. Barriers included: the characteristics and pathways of haematological malignancies; the close patient/haematology team relationship; lack of role clarity; late end of life discussions and SPC referrals; policy issues; and organisational issues. The main facilitators identified were: establishment of interdisciplinary working patterns (co-working) and enhanced understanding of roles; timely discussions with patients and early SPC referral; access to information platforms able to support information sharing; and use of indicators to ‘flag’ patients’ needs for SPC. Collaboration between haematology and SPC was perceived as beneficial and desirable, and was said to be increasing over time. Conclusions: This is the first UK study to explore SPC practitioners’ perceptions concerning haematology patient referrals. Numerous factors were found to influence the likelihood of referral, some of which related to the organisation and delivery of SPC services, so were amenable to change, and others relating to the complex and unique characteristics and pathways of haematological cancers. Further research is needed to assess the extent to which palliative care is provided by haematology doctors and nurses and other generalists and ways in which clinical uncertainty could be used as a trigger, rather than a barrier, to referral. Keywords: Cancer, Leukaemia, Lymphoma, Myeloma, Haematology, Specialist palliative care, End of life, Hospice, Qualitativ

Recovery of the crucian carp Carassius carassius (L.): Approach and early results of an English conservation project

Aquatic Conservation: Marine and Freshwater Ecosystems published by John Wiley & Sons Ltd The crucian carp Carassius carassius, a cyprinid fish characteristic of small ponds, is in decline throughout most of its European range, including in England where it is currently thought to be non-native. The present study, undertaken by the Norfolk Crucian Project, reports on reductions in pond populations of crucian carp in Norfolk, eastern England as well as the success of recent introduction/re-introduction efforts in terms of crucian survival, recruitment and growth over the last 10 years. A 72% decline in crucian carp distribution was observed between the 1950s–1980s and the 2010s. Of 18 crucian carp introductions/re-introductions to restored and suitable existing ponds, 17 were successful in terms of survival, increasing the number of current crucian sites in Norfolk by 37%. Recruitment of young crucian carp was demonstrated for 12 of the 18 stocked ponds, with apparent elevated juvenile growth relative to other English and European populations. Delays in, or a lack of, crucian recruitment in some ponds appeared to result from the presence of other fish species (especially threespine stickleback Gasterosteus aculeatus) with predation and interspecific competition possible contributory factors. This study shows that, through combinations of pond rehabilitation and stocking, it has been possible to achieve a substantial recovery of crucian carp populations in the study region. Although the crucian carp is currently presumed to be non-native within England, given other scientific studies that show a lack of adverse impacts of this species on native biota, and because it is greatly threatened in its native range, the call is sounded for more crucian carp conservation projects in other parts of England as well as in Europe more generally

Turbulence in the ice shelf–ocean boundary current and its sensitivity to model resolution

The ice shelf-ocean boundary current has an important control on heat delivery to the base of an ice shelf. Climate and regional models that include a representation of ice shelf cavities often use a coarse grid and results have a strong dependence on resolution near the ice shelf-ocean interface. This study models the ice shelf-ocean boundary current with a non-hydrostatic z-level configuration at turbulence-permitting resolution (1 m). The z-level model performs well when compared against state-of-the-art Large Eddy Simulations showing its capability in representing the correct physics. We showthat theoretical results from a one-dimensional model with parameterised turbulence reproduce the z-level model results to a good degree, indicating possible utility as a turbulence closure. The one-dimensional model evolves to a state of marginal instability and we use the z-level model to demonstrate how this is represented in three-dimensions. Instabilities emerge that regulate the strength of the pycnocline and coexist with persistent Ekman rolls, which are identified prior to the flow becoming intermittently unstable. When resolution of the z-level model is degraded to understand the grid-scale dependencies, the degradation is dominated by the established problem of excessive numerical diffusion. We show that at intermediate resolutions (2-4 m), the boundary layer structure can be partially recovered by tuning diffusivities. Lastly, we compare replacing prescribed melting with interactive melting that is dependent on the local ocean conditions. Interactive melting results in a feedback such that the system evolves more slowly, which is exaggerated at lower resolution

Identifying the science and technology dimensions of emerging public policy issues through horizon scanning

Public policy requires public support, which in turn implies a need to enable the public not just to understand policy but also to be engaged in its development. Where complex science and technology issues are involved in policy making, this takes time, so it is important to identify emerging issues of this type and prepare engagement plans. In our horizon scanning exercise, we used a modified Delphi technique [1]. A wide group of people with interests in the science and policy interface (drawn from policy makers, policy adviser, practitioners, the private sector and academics) elicited a long list of emergent policy issues in which science and technology would feature strongly and which would also necessitate public engagement as policies are developed. This was then refined to a short list of top priorities for policy makers. Thirty issues were identified within broad areas of business and technology; energy and environment; government, politics and education; health, healthcare, population and aging; information, communication, infrastructure and transport; and public safety and national security.Public policy requires public support, which in turn implies a need to enable the public not just to understand policy but also to be engaged in its development. Where complex science and technology issues are involved in policy making, this takes time, so it is important to identify emerging issues of this type and prepare engagement plans. In our horizon scanning exercise, we used a modified Delphi technique [1]. A wide group of people with interests in the science and policy interface (drawn from policy makers, policy adviser, practitioners, the private sector and academics) elicited a long list of emergent policy issues in which science and technology would feature strongly and which would also necessitate public engagement as policies are developed. This was then refined to a short list of top priorities for policy makers. Thirty issues were identified within broad areas of business and technology; energy and environment; government, politics and education; health, healthcare, population and aging; information, communication, infrastructure and transport; and public safety and national security