Foraminiferal biodiversity associated with cold-water coral carbonate mounds and open slope of SE Rockall Bank (Irish continental margin-NE Atlantic)

Cold-water coral (CWC) ecosystems are hotspots of macro- and microfaunal biodiversity and provide refuge for a wide variety of deep-sea species. We investigated how the abundance and biodiversity of 'live' (Rose Bengal stained) foraminifera varies with, and is related to, the occurrence of CWC on the Rockall Bank (NE Atlantic). Qualitative and quantitative analyses were performed on 21 replicate samples from 8 deep-sea stations, including 4 stations on CWC-covered carbonate mounds at depths of 567-657 m, and 4 stations on the adjacent slope at depths of 469-1958 m where CWC were absent. This sampling strategy enabled us to demonstrate that sediments surrounding the living CWC were characterised by higher foraminiferal abundance and biodiversity than open-slope sediments from the same area. A total of 163 foraminiferal species was identified. The dominant species in CWC sediments were: Spirillina vivipara, Allogromiid sp. 1. Globocassidulina subglobosa, Adercotryma wrighti, Eponides pusillus, Ehrenbergina carinata, Planulina ariminensis, Trochammina inflate and Paratrochammina challenged. Foraminifera were nearly absent in adjacent open slope areas subject to strong tidal currents and characterised by coarse grained deposits. We suggest that CWC create a heterogeneous three-dimensional substrate offering microhabitats to a diverse benthic foraminiferal community

A regional benthic fauna assessment method for the Southern North Sea using Margalef diversity and reference value modelling

The aims of this study are to develop an optimized method for regional benthic fauna assessment of the Southern North Sea which (a) is sensitive and precise (quantified as the slope and the R2 value of the pressure-impact relationships, respectively) for the anthropogenic pressures bottom fishing and organic enrichment, (b) is suitable for estimating and modelling reference values, (c) is transparent, (d) can be efficiently applied using dedicated software; and to apply this method to benthic data from the Southern North Sea. Margalef diversity appeared to be the best performing benthic index regarding these criteria, even better than several Multi-Metric Indices (MMIs) containing e.g. AMBI (AZTI Marine Biotic Index) and ITI (Infaunal Trophic Index). Therefore, this relatively simple and very practical index, including a new reference value estimation and modelling method, and BENMMI software were selected as a common OSPAR (Oslo Paris convention) method for the benthic fauna assessment of the Southern North Sea. This method was applied to benthic fauna data from the Southern North Sea collected during the period 2010–2015. The results in general show lower normalized Margalef values in coastal areas, and higher normalized Margalef values in deeper offshore areas. The following benthic indices were compared in this study: species richness, Margalef diversity, SNA index, Shannon index, PIE index, AMBI, ITI. For each assessment area, the least disturbed benthic dataset was selected as an adjacent 6 year period with, on average, the highest Margalef diversity values. For these datasets, the reference values were primarily set as the 99th percentile values of the respective indices. This procedure results in the highest stable reference values that are not outliers. In addition, a variable percentile method was developed, in which the percentile value is adjusted to the average bottom fishing pressure (according to data from the International Council for the Exploration of the Sea, ICES) in the period 2009–2013. The adjusted percentile values were set by expert judgement, at 75th (low fishing pressure), 95th (medium fishing pressure) and 99th (high fishing pressure) percentile. The estimated reference values for Margalef diversity correlate quite well with the median depth of the assessment areas using a sigmoid model (pseudo-R2 = 0.86). This relationship between depth and Margalef diversity was used to estimate reference values in case an assessment area had insufficient benthic data .For testing the effects of bottom fishing pressure, normalized index values (NIV; index value divided by reference value) were used. The rationale for using NIVs is the assumption that, although a certain level of bottom fishing pressure will have a larger absolute effect on more biodiverse benthic communities in deeper waters than on more robust and less biodiverse coastal benthic communities, the relative effects (tested using NIVs) are comparable. A clear exponentially decreasing relationship (R2 = 0.26–0.27, p 2 cm, respectively) and normalized Margalef diversity values, with an asymptotic normalized Margalef value of 0.45 at a subsurface fishing activity >2.3 sweeps/year. This asymptotic value is predominantly found in coastal waters, and probably shows that the naturally more robust coastal benthic communities have been transformed into resilient benthic communities, which rapidly recover from increasing fishing pressure

Trends in biomass, density and diversity of North Sea macrofauna

Total biomass and biomass of large taxonomic groups (polychaetes, molluscs, crustaceans, echinoderms) and species diversity of the macrofauna were determined for almost 200 North Sea stations sampled synoptically by seven vessels during Spring 1986 and for 120 additional stations sampled in earlier years by the Marine Laboratory in Aberdeen. There exists a clear and significant decreasing trend in biomass with latitude, both in total biomass and for the different taxonomic groups. Apart from latitude, sediment composition and chlorophyll a content of the sediment also infuence total biomass and biomass of most groups significantly. Biomass increases consistently in finer sediments and sediments with a higher chlorophyll a content. The same trends are found for the results within laboratories. Some interaction exists, indicating weak laboratory and zonal effects. Diversity, as measured by Hill's diversity index N1 = (exp H′) shows a clear and significant trend with latitude. Towards the north of the North Sea diversity increases considerably. The trend is also found for laboratories separately and is everywhere equally strong. Also longitude and depth show an effect on diversity. Sediment variables have no clear influence on diversity. Other diversity measures show the same trend but are more variable than N1,. Total density tends to increase towards the north, but sediment related variables have a larger influence. Mean individual weight becomes considerably smaller towards the northern part of the North Sea

Long-term Observations Reveal Environmental Conditions and Food Supply Mechanisms at an Arctic Deep-Sea Sponge Ground

Deep-sea sponge grounds are hotspots of benthic biomass and diversity. To date, very limited data exist on the range of environmental conditions in areas containing deep-sea sponge grounds and which factors are driving their distribution and sustenance. We investigated oceanographic conditions at a deep-sea sponge ground located on an Arctic Mid-Ocean Ridge seamount. Hydrodynamic measurements were performed along Conductivity-Temperature-Depth transects, and a lander was deployed within the sponge ground that recorded near-bottom physical properties as well as vertical fluxes of organic matter over an annual cycle. The data demonstrate that the sponge ground is found at water temperatures of −0.5°C to 1°C and is situated at the interface between two water masses at only 0.7° equatorward of the turning point latitude of semi-diurnal lunar internal tides. Internal waves supported by vertical density stratification interact with the seamount topography and produce turbulent mixing as well as resuspension of organic matter with temporarily very high current speeds up to 0.72 m s−1. The vertical movement of the water column delivers food and nutrients from water layers above and below toward the sponge ground. Highest organic carbon flux was observed during the summer phytoplankton bloom period, providing fresh organic matter from the surface. The flux of fresh organic matter is unlikely to sustain the carbon demand of this ecosystem. Therefore, the availability of bacteria, nutrients, and dissolved and particulate matter, delivered by tidally forced internal wave turbulence and transport by horizontal mean flows, likely plays an important role in meeting ecosystem-level food requirements

Role of deep sponge grounds in the Mediterranean Sea: a case study in southern Italy

The Mediterranean spongofauna is relatively well-known for habitats shallower than 100 m, but, differently from oceanic basins, information upon diversity and functional role of sponge grounds inhabiting deep environments is much more fragmentary. Aims of this article are to characterize through ROV image analysis the population structure of the sponge assemblages found in two deep habitats of the Mediterranean Sea and to test their structuring role, mainly focusing on the demosponges Pachastrella monilifera Schmidt, 1868 and Poecillastra compressa (Bowerbank, 1866). In both study sites, the two target sponge species constitute a mixed assemblage. In the Amendolara Bank (Ionian Sea), where P. compressa is the most abundant species, sponges extend on a peculiar tabular bedrock between 120 and 180 m depth with an average total abundance of 7.3 +/- 1.1 specimens m(-2) (approximately 230 gWW m(-2) of biomass). In contrast, the deeper assemblage of Bari Canyon (average total abundance 10.0 +/- 0.7 specimens m(-2), approximately 315 gWW m(-2) of biomass), located in the southwestern Adriatic Sea between 380 and 500 m depth, is dominated by P. monilifera mixed with living colonies of the scleractinian Madrepora oculata Linnaeus, 1758, the latter showing a total biomass comparable to that of sponges (386 gWW m(-2)). Due to their erect growth habit, these sponges contribute to create complex three-dimensional habitats in otherwise homogenous environments exposed to high sedimentation rates and attract numerous species of mobile invertebrates (mainly echinoderms) and fish. Sponges themselves may represent a secondary substrate for a specialized associated fauna, such zoanthids. As demonstrated in oceanic environments sponge beds support also in the Mediterranean Sea locally rich biodiversity levels. Sponges emerge also as important elements of benthic-pelagic coupling in these deep habitats. In fact, while exploiting the suspended organic matter, about 20% of the Bari sponge assemblage is also severely affected by cidarid sea urchin grazing, responsible to cause visible damages to the sponge tissues (an average of 12.1 +/- 1.8 gWW of individual biomass removed by grazing). Hence, in deep-sea ecosystems, not only the coral habitats, but also the grounds of massive sponges represent important biodiversity reservoirs and contribute to the trophic recycling of organic matter

Meiofauna in the Gollum Channels and the Whittard Canyon, Celtic Margin—How Local Environmental Conditions Shape Nematode Structure and Function

The Gollum Channels and Whittard Canyon (NE Atlantic) are two areas that receive high input of organic matter and phytodetritus from euphotic layers, but they are typified by different trophic and hydrodynamic conditions. Sediment biogeochemistry was analysed in conjunction with structure and diversity of the nematode community and differences were tested between study areas, water depths (700 m vs 1000 m), stations, and sediment layers. The Gollum Channels and Whittard Canyon harboured high meiofauna abundances (1054–1426 ind. 10 cm−2) and high nematode diversity (total of 181 genera). Next to enhanced meiofauna abundance and nematode biomass, there were signs of high levels of organic matter deposition leading to reduced sedimentary conditions, which in turn structured the nematode community. Striking in this respect was the presence of large numbers of ‘chemosynthetic’ Astomonema nematodes (Astomonema southwardorum, Order Monhysterida, Family Siphonolaimidae). This genus lacks a mouth, buccal cavity and pharynx and possesses a rudimentary gut containing internal, symbiotic prokaryotes which have been recognised as sulphur-oxidising bacteria. Dominance of Astomonema may indicate the presence of reduced environments in the study areas, which is partially confirmed by the local biogeochemical environment. The nematode communities were mostly affected by sediment layer differences and concomitant trophic conditions rather than other spatial gradients related to study area, water depth or station differences, pointing to small-scale heterogeneity as the main source of variation in nematode structure and function. Furthermore, the positive relation between nematode standing stocks, and quantity and quality of the organic matter was stronger when hydrodynamic disturbance was greater. Analogically, this study also suggests that structural diversity can be positively correlated with trophic conditions and that this relation is tighter when hydrodynamic disturbance is greater

Surface Treatments for Inkjet Printing onto a PTFE-Based Substrate for High Frequency Applications

This document is the Accepted Manuscript version of a Published Work that appeared in final form in the journal Industrial and Engineering Chemistry Research [copyright © American Chemical Society] after peer review and technical editing by the publisher. To access the final edited and published work see: http://pubs.acs.org/doi/abs/10.1021/ie4006639Inkjet printing onto laminates for use in high frequency applications (high frequency laminates) is challenging, due to the substrate surface roughness present after etching away the copper layer(s). This has a detrimental effect on interconnect losses as the frequency increases. In this paper, different surface treatments to reduce the surface roughness of a typical high frequency laminate (RO3006) are investigated. In particular, the importance of matching the substrate surface energy to the ink to achieve a smooth coated layer for the case of a UV cured insulator is demonstrated. This is achievable within the parameters of heating the platen, which is a more flexible approach compared to modifying the ink to improve the ink-substrate interaction. In printing onto the surface modified substrates, the substrate roughness was observed to affect the printed line width significantly. A surface roughness factor was introduced to take into account the phenomenon by modifying the original formula of Smith et al. Lastly, the authors show that the printed line widths are also influenced by the surface tension arising from charges present on the surface modified substrates