Quality of cochlear implant rehabilitation under COVID-19 conditions.

BACKGROUND: The rehabilitation process following cochlear implant (CI) surgery is carried out in a multimodal therapy according to German national guidelines and includes technical and medical aftercare. In times of the corona pandemic surgery and rehabilitation appointments were cancelled or delayed leading to a more difficult access to auditory rehabilitation. Newly implemented hygiene modalities due to the SARS-CoV­2 pandemic have changed medical aftercare and the rehabilitation process. The aim of this study was to evaluate the quality of rehabilitation under corona conditions. MATERIAL AND METHODS: An anonymous survey of adult cochlear implant patients was carried out by a non-standardized questionnaire. Demographics were analyzed and the quality of medical aftercare, speech therapy, technical aftercare, psychological support and the hygiene modalities were compared to previous rehabilitation stays. RESULTS: In total 109 patients completed the questionnaire. The quality of rehabilitation and individual therapy were rated as qualitatively similar or improved. The threat of the pandemic and fear of corona were rated unexpectedly high with 68% and 50%, respectively. The hygiene measures during the rehabilitation stay eased subjective fears at the same time. The majority of patients were annoyed by wearing face masks but visors, protection shields and social distancing were more tolerated. CONCLUSION: The implementation of the new hygiene modalities within the therapeutic rehabilitation setting was well-accepted by patients allowing access to auditory rehabilitation. A successful rehabilitation should ensure a fear-free environment by adhering to the necessary hygiene modalities.

[Quality of cochlear implant rehabilitation under COVID-19 conditions. German version]. / Qualität der Cochleaimplantat-Rehabilitation unter COVID-19-Bedingungen.

BACKGROUND: The rehabilitation process following cochlear implant (CI) surgery is carried out in a multimodal therapy according to German national guidelines and includes technical and medical aftercare. In times of the corona pandemic surgery and rehabilitation appointments were cancelled or delayed leading to a more difficult access to auditory rehabilitation. Newly implemented hygiene modalities due to the SARS-CoV­2 pandemic have changed medical aftercare and the rehabilitation process. The aim of this study was to evaluate the quality of rehabilitation under corona conditions. MATERIAL AND METHODS: An anonymous survey of adult cochlear implant patients was carried out by a non-standardized questionnaire. Demographics were analyzed and the quality of medical aftercare, speech therapy, technical aftercare, psychological support and the hygiene modalities were compared to previous rehabilitation stays. RESULTS: In total 109 patients completed the questionnaire. The quality of rehabilitation and individual therapy were rated as qualitatively similar or improved. The threat of the pandemic and fear of corona were rated unexpectedly high with 68% and 50%, respectively. The hygiene measures during the rehabilitation stay eased subjective fears at the same time. The majority of patients were annoyed by wearing face masks but visors, protection shields and social distancing were more tolerated. CONCLUSION: The implementation of the new hygiene modalities within the therapeutic rehabilitation setting was well-accepted by patients allowing access to auditory rehabilitation. A successful rehabilitation should ensure a fear-free environment by adhering to the necessary hygiene modalities.

Effects of isoquinoline alkaloids from Macleaya cordata on physiological, immunological and inflammatory parameters in healthy beagles: Alkaloids in dog nutrition.

The aim of the study was to investigate nutritional, physiological and immunological effects of a plant-derived blend of isoquinoline alkaloids (Sangrovit® Extra) in healthy dogs. Two groups of healthy, adult beagles (N = 10) were tested in a cross-over experiment, lasting two consecutive three-week periods. The experimental group received 1.2 g additive/kg feed, according to the recommendation of 10-20 mg/kg live weight per day. The control group received the same feed without additive. Complete blood count, immunological parameters and amino acid concentrations in serum were assessed. Faeces were analysed for short-chain fatty acids, lactate and ammonium; moreover, their quantity and consistency were determined. Neither feed intake, total apparent nutrient digestibility (crude protein and fat, organic matter, sodium, potassium) were affected by intake of the product. Lymphocyte and monocyte counts were slightly increased in both groups. Elevation was not treatment dependant. IgA, IgG, haptoglobin in serum and flow cytometric phenotyping of peripheral lymphocytes were not affected by alkaloids supplementation. Numerically greater methionine concentrations in blood serum occurred in the experimental group (p = 0.182). Quantity and consistency of faeces and ammonium concentration in faeces were not affected by the additive. Faecal concentrations of short-chain organic acids differed between groups (acetic acid, % of total SCFA: control group 52.3 ± 5.2 vs. experimental group 57.1 ± 4.5, p = 0.042), lactate concentrations (d-, l- and total) did not. Due to the shift of SCFA proportions in faeces, an effect of isoquinoline alkaloids (IQs) on the metabolic activity of intestinal microbiota is probable. In conclusion, the addition of IQs in the given dose was well tolerated and did not have adverse effects in healthy dogs.

Data integration for identification of important transcription factors of STAT6-mediated cell fate decisions.

Data integration has become a useful strategy for uncovering new insights into complex biological networks. We studied whether this approach can help to delineate the signal transducer and activator of transcription 6 (STAT6)-mediated transcriptional network driving T helper (Th) 2 cell fate decisions. To this end, we performed an integrative analysis of publicly available RNA-seq data of Stat6-knockout mouse studies together with STAT6 ChIP-seq data and our own gene expression time series data during Th2 cell differentiation. We focused on transcription factors (TFs), cytokines, and cytokine receptors and delineated 59 positively and 41 negatively STAT6-regulated genes, which were used to construct a transcriptional network around STAT6. The network illustrates that important and well-known TFs for Th2 cell differentiation are positively regulated by STAT6 and act either as activators for Th2 cells (e.g., Gata3, Atf3, Satb1, Nfil3, Maf, and Pparg) or as suppressors for other Th cell subpopulations such as Th1 (e.g., Ar), Th17 (e.g., Etv6), or iTreg (e.g., Stat3 and Hif1a) cells. Moreover, our approach reveals 11 TFs (e.g., Atf5, Creb3l2, and Asb2) with unknown functions in Th cell differentiation. This fact together with the observed enrichment of asthma risk genes among those regulated by STAT6 underlines the potential value of the data integration strategy used here. Thus, our results clearly support the opinion that data integration is a useful tool to delineate complex physiological processes.

A large-scale study of microplastic abundance in sediment cores from the UK continental shelf and slope.

To inform risk assessments, reliable, time efficient and affordable quantification methods are required for creating a microplastic (MP) pollution baseline in the world's oceans. To facilitate this, MP abundance was investigated in sediments of three contrasting areas of the UK continental shelf: North West of Jones Bank, the Canyons in the Celtic Sea and Dogger Bank in the North Sea, utilising the Nile Red tagging method to assess its time efficiency and cost. Average MP abundance in the top 10 cm was 1050-2700 MP kg-1. MP abundance decreased with increasing sediment depth and increased with increasing water depth. The findings emphasise the extent of MP pollution and illustrate the value of Nile Red for large scale mapping at relatively low cost.

Agrin isoforms and their role in synaptogenesis.

Agrin is thought to mediate the motor neuron-induced aggregation of synaptic proteins on the surface of muscle fibers at neuromuscular junctions. Recent experiments provide direct evidence in support of this hypothesis, reveal the nature of agrin immunoreactivity at sites other than neuromuscular junctions, and have resulted in findings that are consistent with the possibility that agrin plays a role in synaptogenesis throughout the nervous system.

[Neuromuscular signal transmission in adulthood. Current facets of acquired and hereditary disorders]. / Neuromuskuläre Signalübertragung im Erwachsenenalter. Aktuelle Facetten erworbener und angeborener Störungen.

The availability of early diagnosis and modern effective therapies has reduced mortality and disability linked to late-onset acquired or hereditary neuromuscular transmission disorders. Nevertheless, identification of the pathogenesis of these diseases remains a challenge. In addition to non-specific and fluctuating presenting symptoms current diagnostic work-up strategies include electrophysiology, antibody measurements and less frequently molecular genetics. For differential diagnostic purposes there is an increasing demand for improving awareness concerning late-onset congenital myasthenic syndromes (CMS) which are rare but nevertheless symptomatically treatable diseases. Especially in seronegative myasthenic syndromes, molecular genetic analyses of CMS genes should be integrated into the differential diagnostic work-up. Therefore, some facets of neuromuscular synaptogenesis in the context of seronegative acquired myasthenic syndromes and recently uncovered congenital myasthenic syndromes are reviewed.

In vitro aflatoxin B(1) exposure decreases response to carbamylcholine in the jejunal epithelium of broilers.

The study was conducted to evaluate if aflatoxin B(1) (AFB(1)) has the capacity to affect the electrophysiological variables and active glucose uptake in jejunal epithelium of chicken. For this purpose, intestinal segments from the middle jejunum of broilers (35 to 39 d old) were incubated in Ussing chambers in the presence of 0 (vehicle control), 1.25, 2.50, and 3.75 microg of AFB(1)/mL of buffer. After 40 and 60 min of incubation with AFB(1), d-glucose (20 mmol/L) and carbamylcholine (200 micromol/L; an analog of acetylcholine and inducer of apical Cl(-) secretion) were respectively added to the incubation medium. Addition of 3.75 microg of AFB(1) caused an increase (P < 0.04) in short-circuit current (I(sc)) and transmural potential difference (V(t)) between 12 to 27 min postexposure as compared with the control. Glucose-induced DeltaI(sc) and percentage of DeltaV(t) were reduced (P < 0.04) at 2.5 and 3.75 microg of AFB(1)/mL, respectively, as compared with the control. The carbamylcholine-induced DeltaI(sc) and DeltaV(t) were both lower (P < 0.05) at 3.75 microg of AFB(1)/mL as compared with the control (-0.05 microA/cm(2), 0.1 mV vs. 1.1 microA/cm(2), and 0.6 mV, respectively). These observations indicate that acute exposure to AFB(1) may increase apical anion secretion in the jejunal epithelium of chicken. The negative effect of this increased anion secretion on active glucose uptake was, however, not prominent and may be considered as moderate or progressive in nature.

[Long-term functional outcomes of cochlear implants in children]. / Langzeitergebnisse nach Kochleaimplantatversorgung bei Kindern.

The treatment of deaf and hearing-impaired children with cochlear implants has been established for several years. Nonetheless, no long-term results exist for studies of a representatively large number of children in the German-speaking area. These are necessary in order to formulate prognoses regarding the development and results of children undergoing implantation at various ages. In a retrospective study, we assessed the data of 156 children with various implantation ages and a minimum follow-up period of 5 years for whom speech and audiological data (Oldenburg Sentence Test, Freiburg words/numbers test) were available. Our findings confirm the assumption that early-implanted children (<2 years) achieve the best speech-comprehension results. For this reason, support for a sufficient universal neonate hearing screen should be emphatically given so that implantation, after a hearing test phase, can be targeted in the first year of life. The surgical, anesthesiological, and rehabilitation conditions must be fulfilled, and surgical experience is required for operation on infants and small children.

[Cochlear implant for malformations of the inner ear]. / Kochleaimplantat bei Innenohrfehlbildungen.

The radiologic evaluation of the temporal bone in cochlear implant candidates can detect malformations of the inner ear in up to 20% of cases. The aim of our study was to analyze and classify malformations of the inner ear in patients with cochlear implants carried out from 2001 to 2009. Malformations of the inner ear, including malformations of the internal auditory canal were detected in 12.7% of children and 3.4% of adults. Mondini dysplasia was most common and occurred in 45% of cases. The surgical procedure had to be adapted according to the individual malformation. Modification of surgical access, management of intraoperative CSF gusher, choice of electrode array, intraoperative imaging and the use of navigation were the most important factors. Rehabilitation results were generally very positive and corresponded to the expectation depending on the duration of deafness, if no additional handicaps were present.

Molecular mechanisms separating two axonal pathways during embryonic development of the avian optic tectum.

During embryonic development of the avian optic tectum, retinal and tectobulbar axons form an orthogonal array of nerve processes. Growing axons of both tracts are transiently very closely apposed to each other. Despite this spatial proximity, axons from the two pathways do not intermix, but instead restrict their growth to defined areas, thus forming two separate plexiform layers, the stratum opticum and the stratum album centrale. In this study we present experimental evidence indicating that the following three mechanisms might play a role in segregating both axonal populations: Retinal and tectobulbar axons differ in their ability to use the extracellular matrix protein laminin as a substrate for axonal elongation; the environment in the optic tectum is generally permissive for retinal axons, but is specifically nonpermissive for tectobulbar axons, resulting in a strong fasciculation of the latter; and growth cones of temporal retinal axons are reversibly inhibited in their motility by direct contact with the tectobulbar axon's membrane.

cDNA that encodes active agrin.

Agrin is thought to mediate the motor neuron-induced aggregation of AChRs and AChE on the surface of muscle fibers at neuromuscular junctions. We have isolated a cDNA from a chick brain library that, based on sequence homology and expression experiments, codes for active agrin. Examination of the sequence reveals considerable similarity to homologous cDNAs previously isolated from ray and rat libraries. A conspicuous difference is an insertion of 33 bp in chick agrin cDNA, which endows the encoded protein with AChR/AChE aggregating activity. Homologous transcripts having the 33 bp insertion were detected in the ray CNS, which indicates that an insertion of similar size is conserved in agrin in many, if not all, vertebrate species. Results of in situ hybridization studies and PCR experiments on mRNA isolated from motor neuron-enriched fractions of the spinal cord indicate that, consistent with the agrin hypothesis, motor neurons contain transcripts that code for active agrin.

The agrin gene codes for a family of basal lamina proteins that differ in function and distribution.

We isolated two cDNAs that encode isoforms of agrin, the basal lamina protein that mediates the motor neuron-induced aggregation of acetylcholine receptors on muscle fibers at the neuromuscular junction. Both proteins are the result of alternative splicing of the product of the agrin gene, but unlike agrin, they are inactive in standard acetylcholine receptor aggregation assays. They lack one (agrin-related protein 1) or two (agrin-related protein 2) regions in agrin that are required for its activity. Expression studies provide evidence that both proteins are present in the nervous system and muscle and that, in muscle, myofibers and Schwann cells synthesize the agrin-related proteins while the axon terminals of motor neurons are the sole source of agrin.

Characteristics of neurons and glia in the brain of Fukuyama type congenital muscular dystrophy.

Fukuyama type congenital muscular dystrophy accompanies central nervous system and ocular lesions. Morphological findings suggest that major central nervous system lesions, such as cortical dysplasia, are caused by the abnormal glia limitans due to an impairment of astrocytes. Increase of corpora amylacea and neurofibrillary tangles suggests acceleration of the aging process in the Fukuyama type congenital muscular dystrophy brain. Glycosylation of alpha-dystroglycan is decreased in the central nervous system of Fukuyama type congenital muscular dystrophy in a similar manner to the skeletal muscle, but dystroglycan mRNA levels appear to be increased. Glycosylated alpha-dystroglycan is reduced in the glia limitans formed by astrocytic endfeet. Slight accumulation of N(epsilon)-(carboxymethyl)lysine, an oxidative modification product, is observed in astrocytes of Fukuyama type congenital muscular dystrophy and in an astrocytoma cell line with suppressed fukutin expression. Cerebral cortical neurons of Fukuyama type congenital muscular dystrophy and controls react with an antibody for core alpha-dystroglycan but not with an antibody for glycosylated alpha-dystroglycan. Carboxymethyl lysine is accumulated in cortical neurons of a severe case of Fukuyama type congenital muscular dystrophy. Both astrocytes and neurons appear to be sensitive to oxidative stress when fukutin is suppressed. However, it is still unclear how the loss of fukutin causes astrocytic and neuronal dysfunction. Since the central nervous system is composed of several components that are closely related to each other, more investigations are needed for thorough understanding of the Fukuyama type congenital muscular dystrophy brain. Moreover, since astrocytes and epithelial cells may show different cellular responses to fukutin suppression, it seems important to evaluate the functions of fukutin in each type of cell or tissue, not only to prove the pathogenesis of Fukuyama type congenital muscular dystrophy, but also for applying appropriate therapies, especially those at molecular level.

Influence of differently processed yeast (Kluyveromyces fragilis) on feed intake and gut physiology in weaned pigs.

Two feeding trials were conducted to investigate the effects of hydrolyzed (HY) or non-hydrolyzed (NHY) yeast (Kluyveromyces fragilis) in isoenergetic and isonitrogeneous diets in the postweaning period. In experiment 1, a total of 550 unsexed pigs (6.5 ± 0.5 kg BW), weaned at 24 ± 2 d of age, were allocated to five treatment groups, receiving either a control diet (CON) or diets with 1%, 3%, and 5% HY (groups HY1, HY3, and HY5, respectively), or a diet with 3% NHY (group NHY3). In experiment 2, a total of 48 male and female pigs (6.2 ± 0.3 kg BW, weaned at d 25) were allocated to three dietary groups (n = 8 replicates with two pigs) receiving a control diet (CON) or diets with 1% NHY or 1% HY. Eight animals were sacrificed 2 wk after weaning for histological investigations in the jejunum and colon, determination of apparent ileal digestibility (AID) of CP and ether extract (EE), and electrophysiological measurements in the jejunal tissue after addition of carbachol or l-glutamine using Ussing chambers. In experiment 1, different treatments had no significant effect on pig performance, but diet HY1 tended to increase ADG and G:F in wk 2 after weaning (P < 0.1). In experiment 2, diet HY1 increased feed intake in wk 2 (P < 0.05), whereas NHY yeast had no effect on feed intake. Villus height, villus/crypt ratio in jejunum (P < 0.05), and crypt depth in colon (P < 0.01) were increased in group HY1. Crypt depth in jejunum and small intestinal length were not affected by different treatments. The AID of CP and EE tended to increase in group HY1 (P < 0.1) compared with groups CON and NHY. In the Ussing chamber experiments, no changes in basal electrophysiological parameters were observed, and the reactions of the treatment groups to carbachol and l-glutamine were comparable. ADFI was positively correlated with different parameters of intestinal morphology (villus height, villus/crypt ratio, crypt depth in colon, length of small intestine), AID of CP, EE, and performance. The results suggest that a supplementation of 1% HY based on K. fragilis to pig diets may positively influence ADFI and intestinal morphology in pig in the early postweaning period (d 1 to 14).

Influence of lignocellulose and low or high levels of sugar beet pulp on nutrient digestibility and the fecal microbiota in dogs.

Lignocellulose is an alternative fiber source for dogs; however, it has not yet been studied as a feed ingredient for the nutrition of dogs. Eight adult Beagles were involved in the study, which consisted of 3 feeding periods of 8 to 12 wk each. All dogs received 3 different diets, which either had the same concentration of fiber sources (2.7% sugar beet pulp or lignocellulose) or were formulated for a similar concentration of approximately 3% crude fiber: 12% sugar beet pulp (highSBP; 3.1% crude fiber), 2.7% sugar beet pulp (lowSBP; 0.96% crude fiber), or 2.7% lignocellulose (LC; 2.4% crude fiber). Feces samples were collected at the end of each feeding period, and the apparent nutrient digestibility, daily amount, and DM content of feces and fecal cell numbers of relevant bacteria were analyzed. The daily feces amount was lower and the feces DM was higher when dogs were fed the LC diet and the lowSBP diet compared with the highSBP diet ( < 0.001). Apparent digestibility of CP, Na, and K was highest with the lowSBP diet followed by the LC and highSBP diets ( < 0.001). After feeding LC, the bacterial cell counts of spp., spp., and the cluster were reduced compared with feeding highSBP and even more reduced after feeding lowSBP ( < 0.001). The bacterial cell count of the cluster was lower in LC and lowSBP compared with highSBP ( < 0.001). The feces of dogs fed LC and lowSBP had lower concentrations of acetate ( < 0.001), propionate ( < 0.001), -butyrate ( = 0.015), total fatty acids ( < 0.001), and lactate ( < 0.001) compared with dogs fed highSBP. The concentration of -butyrate was higher in the feces of dogs fed with LC compared with dogs fed high and low sugar beet pulp (SBP; < 0.001). The pH of the feces of the LC-fed dogs was highest followed by lowSBP- and highSBP-fed dogs ( < 0.001). Depending on the concentration, the use of LC and SBP as fiber sources in dog feed has different impacts on the fecal microbiota and the apparent digestibility of nutrients. Therefore, different areas of application should be considered.

Oxygen dynamics in shelf seas sediments incorporating seasonal variability.

Shelf sediments play a vital role in global biogeochemical cycling and are particularly important areas of oxygen consumption and carbon mineralisation. Total benthic oxygen uptake, the sum of diffusive and faunal mediated uptake, is a robust proxy to quantify carbon mineralisation. However, oxygen uptake rates are dynamic, due to the diagenetic processes within the sediment, and can be spatially and temporally variable. Four benthic sites in the Celtic Sea, encompassing gradients of cohesive to permeable sediments, were sampled over four cruises to capture seasonal and spatial changes in oxygen dynamics. Total oxygen uptake (TOU) rates were measured through a suite of incubation experiments and oxygen microelectrode profiles were taken across all four benthic sites to provide the oxygen penetration depth and diffusive oxygen uptake (DOU) rates. The difference between TOU and DOU allowed for quantification of the fauna mediated oxygen uptake and diffusive uptake. High resolution measurements showed clear seasonal and spatial trends, with higher oxygen uptake rates measured in cohesive sediments compared to the permeable sediment. The significant differences in oxygen dynamics between the sediment types were consistent between seasons, with increasing oxygen consumption during and after the phytoplankton bloom. Carbon mineralisation in shelf sediments is strongly influenced by sediment type and seasonality.

Benthic pH gradients across a range of shelf sea sediment types linked to sediment characteristics and seasonal variability.

This study used microelectrodes to record pH profiles in fresh shelf sea sediment cores collected across a range of different sediment types within the Celtic Sea. Spatial and temporal variability was captured during repeated measurements in 2014 and 2015. Concurrently recorded oxygen microelectrode profiles and other sedimentary parameters provide a detailed context for interpretation of the pH data. Clear differences in profiles were observed between sediment type, location and season. Notably, very steep pH gradients exist within the surface sediments (10-20 mm), where decreases greater than 0.5 pH units were observed. Steep gradients were particularly apparent in fine cohesive sediments, less so in permeable sandier matrices. We hypothesise that the gradients are likely caused by aerobic organic matter respiration close to the sediment-water interface or oxidation of reduced species at the base of the oxic zone (NH4 +, Mn2+, Fe2+, S-). Statistical analysis suggests the variability in the depth of the pH minima is controlled spatially by the oxygen penetration depth, and seasonally by the input and remineralisation of deposited organic phytodetritus. Below the pH minima the observed pH remained consistently low to maximum electrode penetration (ca. 60 mm), indicating an absence of sub-oxic processes generating H+ or balanced removal processes within this layer. Thus, a climatology of sediment surface porewater pH is provided against which to examine biogeochemical processes. This enhances our understanding of benthic pH processes, particularly in the context of human impacts, seabed integrity, and future climate changes, providing vital information for modelling benthic response under future climate scenarios.

Comparing benthic biogeochemistry at a sandy and a muddy site in the Celtic Sea using a model and observations.

Results from a 1D setup of the European Regional Seas Ecosystem Model (ERSEM) biogeochemical model were compared with new observations collected under the UK Shelf Seas Biogeochemistry (SSB) programme to assess model performance and clarify elements of shelf-sea benthic biogeochemistry and carbon cycling. Observations from two contrasting sites (muddy and sandy) in the Celtic Sea in otherwise comparable hydrographic conditions were considered, with the focus on the benthic system. A standard model parameterisation with site-specific light and nutrient adjustments was used, along with modifications to the within-seabed diffusivity to accommodate the modelling of permeable (sandy) sediments. Differences between modelled and observed quantities of organic carbon in the bed were interpreted to suggest that a large part (>90%) of the observed benthic organic carbon is biologically relatively inactive. Evidence on the rate at which this inactive fraction is produced will constitute important information to quantify offshore carbon sequestration. Total oxygen uptake and oxic layer depths were within the range of the measured values. Modelled depth average pore water concentrations of ammonium, phosphate and silicate were typically 5-20% of observed values at the muddy site due to an underestimate of concentrations associated with the deeper sediment layers. Model agreement for these nutrients was better at the sandy site, which had lower pore water concentrations, especially deeper in the sediment. Comparison of pore water nitrate with observations had added uncertainty, as the results from process studies at the sites indicated the dominance of the anammox pathway for nitrogen removal; a pathway that is not included in the model. Macrofaunal biomasses were overestimated, although a model run with increased macrofaunal background mortality rates decreased macrofaunal biomass and improved agreement with observations. The decrease in macrofaunal biomass was compensated by an increase in meiofaunal biomass such that total oxygen demand remained within the observed range. The permeable sediment modification reproduced some of the observed behaviour of oxygen penetration depth at the sandy site. It is suggested that future development in ERSEM benthic modelling should focus on: (1) mixing and degradation rates of benthic organic matter, (2) validation of benthic faunal biomass against large scale spatial datasets, (3) incorporation of anammox in the benthic nitrogen cycle, and (4) further developments to represent permeable sediment processes.

An approach for the identification of exemplar sites for scaling up targeted field observations of benthic biogeochemistry in heterogeneous environments.

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. A three-step selection process is proposed in which (1) a target area representative of UK shelf sediment heterogeneity is selected, (2) the target area is assessed for spatial heterogeneity in sediment and habitat type, bed and water column structure and hydrodynamic forcing, and (3) study sites are selected within this target area encompassing the range of spatial heterogeneity required to address key scientific questions regarding shelf scale biogeochemistry, and minimise confounding variables. This led to the selection of four sites within the Celtic Sea that are significantly different in terms of their sediment, bed structure, and macrofaunal, meiofaunal and microbial community structures and diversity, but have minimal variations in water depth, tidal and wave magnitudes and directions, temperature and salinity. They form the basis of a research cruise programme of observation, sampling and experimentation encompassing the spring bloom cycle. Typical variation in key biogeochemical, sediment, biological and hydrodynamic parameters over a pre to post bloom period are presented, with a discussion of anthropogenic influences in the region. This methodology ensures the best likelihood of site-specific work being useful for up-scaling activities, increasing our understanding of benthic biogeochemistry at the UK-shelf scale.