Multiple evolutionary transitions of reproductive strategies in a phylum of aquatic colonial invertebrates.

Parental care is considered crucial for the enhanced survival of offspring and evolutionary success of many metazoan groups. Most bryozoans incubate their young in brood chambers or intracoelomically. Based on the drastic morphological differences in incubation chambers across members of the order Cheilostomatida (class Gymnolaemata), multiple origins of incubation were predicted in this group. This hypothesis was tested by constructing a molecular phylogeny based on mitogenome data and nuclear rRNA genes 18S and 28S with the most complete sampling of taxa with various incubation devices to date. Ancestral character estimation suggested that distinct types of brood chambers evolved at least 10 times in Cheilostomatida. In Eucratea loricata and Aetea spp. brooding evolved unambiguously from a zygote-spawning ancestral state, as it probably did in Tendra zostericola, Neocheilostomata, and 'Carbasea' indivisa. In two further instances, brooders with different incubation chamber types, skeletal and non-skeletal, formed clades (Scruparia spp., Leiosalpinx australis) and (Catenicula corbulifera (Steginoporella spp. (Labioporella spp., Thalamoporella californica))), each also probably evolved from a zygote-spawning ancestral state. The modular nature of bryozoans probably contributed to the evolution of such a diverse array of embryonic incubation chambers, which included complex constructions made of polymorphic heterozooids, and maternal zooidal invaginations and outgrowths.

Are we there yet? Management baselines and biodiversity indicators for the protection and restoration of subtidal bivalve shellfish habitats.

Biodiversity loss and degradation of natural habitats is increasing at an unprecedented rate. Of all marine habitats, biogenic reefs created by once-widespread shellfish, are now one of the most imperilled, and globally scarce. Conservation managers seek to protect and restore these habitats, but suitable baselines and indicators are required, and detailed scientific accounts are rare and inconsistent. In the present study the biodiversity of a model subtidal habitat, formed by the keystone horse mussel Modiolus modiolus (L.), was analysed across its Northeast Atlantic biogeographical range. Consistent samples of 'clumped' mussels were collected at 16 locations, covering a wide range of environmental conditions. Analysis of the associated macroscopic biota showed high biodiversity across all sites, cumulatively hosting 924 marine macroinvertebrate and algal taxa. There was a rapid increase in macroinvertebrate biodiversity (H') and community evenness (J) between 2 and 10 mussels per clump, reaching an asymptote at mussel densities of 10 per clump. Diversity declined at more northern latitudes, with depth and in coarser substrata with the fastest tidal flows. Diversity metrics corrected for species abundance were generally high across the habitats sampled, with significant latitudinal variability caused by current, depth and substrate type. Faunal community composition varied significantly between most sites and was difficult to assign to a 'typical' M. modiolus assemblage, being significantly influenced by regional environmental conditions, including the presence of algal turfs. Within the context of the rapid global increase in protection and restoration of bivalve shellfish habitats, site and density-specific values of diversity are probably the best targets for conservation management and upon which to base monitoring programmes.

Paleozoic origins of cheilostome bryozoans and their parental care inferred by a new genome-skimmed phylogeny.

Phylogenetic relationships and the timing of evolutionary events are essential for understanding evolution on longer time scales. Cheilostome bryozoans are a group of ubiquitous, species-rich, marine colonial organisms with an excellent fossil record but lack phylogenetic relationships inferred from molecular data. We present genome-skimmed data for 395 cheilostomes and combine these with 315 published sequences to infer relationships and the timing of key events among c. 500 cheilostome species. We find that named cheilostome genera and species are phylogenetically coherent, rendering fossil or contemporary specimens readily delimited using only skeletal morphology. Our phylogeny shows that parental care in the form of brooding evolved several times independently but was never lost in cheilostomes. Our fossil calibration, robust to varied assumptions, indicates that the cheilostome lineage and parental care therein could have Paleozoic origins, much older than the first known fossil record of cheilostomes in the Late Jurassic.

Influence of offshore oil and gas structures on seascape ecological connectivity.

Offshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence-based decision making for decommissioning O&G infrastructure.

Sea-trial verification of a novel system for monitoring biofouling and testing anti-fouling coatings in highly energetic environments targeted by the marine renewable energy industry.

A novel system was developed to deploy settlement panels to monitor biofouling growth in situ and evaluate antifouling coatings at depths representative of operational conditions of full-scale marine renewable energy devices. Biofouling loading, species diversity, and succession were assessed at depths ranging from 25-40 m at four tests sites in Orkney (UK) featuring extreme wave and tidal current exposure to more sheltered conditions. Evaluations were carried out over a period of 8 months with intermediate retrieval of samples after 3 months. Early pioneer fouling communities, comprised of colonial hydroids, were succeeded by tube-forming amphipods across sites while solitary tunicates dominated in greater shelter. The highest biofouling loading was observed on high-density polyethylene (HDPE) panels (6.17 kg m-2) compared with coated steel (3.34 kg m-2) panels after 8 months. Distinct assemblages were present at exposed vs sheltered sites. Better understanding of fouling and antifouling strategies may provide guidance to more effectively manage biofouling impacts in this sector.

Artificial reef design affects benthic secondary productivity and provision of functional habitat.

Novel hard substratum, introduced through offshore developments, can provide habitat for marine species and thereby function as an artificial reef. To predict the ecological consequences of deploying offshore infrastructure, and sustainably manage the installation of new structures, interactions between artificial reefs and marine ecosystem functions and services must be understood. This requires quantitative data on the relationships between secondary productivity and artificial reef design, across all trophic levels. Benthic secondary productivity is, however, one of the least studied processes on artificial reefs.In this study, we show that productivity rates of a common suspension feeder, Flustra foliacea (Linnaeus 1758), were 2.4 times higher on artificial reefs constructed from "complex" blocks than on reefs constructed from "simple" blocks, which had a smaller surface area.Productivity rates were highest on external areas of reefs. Productivity rates decreased by 1.56%, per cm distance into the reef on complex reefs and 2.93% per cm into the reef on simple block reefs. The differences in productivity rates between reefs constructed from simple and complex blocks are assumed to reflect different current regimes and food supply between the external and internal reef areas, according to reef type. Synthesis and applications. Our results show that artificial reef design can affect secondary productivity at low trophic levels. We demonstrate that the incorporation of voids into reef blocks can lead to a greater proportion of the structure serving as functional habitat for benthic species. By including such modifications into the design of artificial reefs, it may be possible to increase the overall productivity capacity of artificial structures.

A checklist of marine bryozoan taxa in Scottish sea regions.

Contemporary and historical bryozoan records were compiled to provide a comprehensive checklist of species in Scottish waters. The checklist comprises 218 species in 58 families, with representatives from each of the extant bryozoan orders. The fauna was relatively sparse compared to other regions for which bryozoan checklists were available e.g. New Zealand and Australia. Six non-indigenous bryozoan species from the Scottish seas region were included in the checklist. Baseline information on species distributions, such as that presented in this checklist, can be used to monitor and manage the impact of human activities on the marine environment, and ultimately preserve marine biodiversity.

Skeletal carbonate mineralogy of Scottish bryozoans.

This paper describes the skeletal carbonate mineralogy of 156 bryozoan species collected from Scotland (sourced both from museum collections and from waters around Scotland) and collated from literature. This collection represents 79% of the species which inhabit Scottish waters and is a greater number and proportion of extant species than any previous regional study. The study is also of significance globally where the data augment the growing database of mineralogical analyses and offers first analyses for 26 genera and four families. Specimens were collated through a combination of field sampling and existing collections and were analysed by X-ray diffraction (XRD) and micro-XRD to determine wt% MgCO3 in calcite and wt% aragonite. Species distribution data and phylogenetic organisation were applied to understand distributional, taxonomic and phylo-mineralogical patterns. Analysis of the skeletal composition of Scottish bryozoans shows that the group is statistically different from neighbouring Arctic fauna but features a range of mineralogy comparable to other temperate regions. As has been previously reported, cyclostomes feature low Mg in calcite and very little aragonite, whereas cheilostomes show much more variability, including bimineralic species. Scotland is a highly variable region, open to biological and environmental influx from all directions, and bryozoans exhibit this in the wide range of within-species mineralogical variability they present. This plasticity in skeletal composition may be driven by a combination of environmentally-induced phenotypic variation, or physiological factors. A flexible response to environment, as manifested in a wide range of skeletal mineralogy within a species, may be one characteristic of successful invasive bryozoans.

Natural marine bacteria as model organisms for the hazard-assessment of consumer products containing silver nanoparticles.

Scarce information is available regarding the fate and toxicology of engineered silver nanoparticles (AgNPs) in the marine environment, especially when compared to other environmental compartments. Hence, the antibacterial activity of the NM-300 AgNPs (OECD programme) and a household product containing colloidal AgNPs (Mesosilver) was investigated using marine bacteria, pure cultures and natural mixed populations (microcosm approach). Bacterial susceptibility to AgNPs was species-specific, with Gram negative bacteria being more resistant than the Gram positive species (NM-300 concentration used ranged between 0.062 and 1.5 mg L-1), and the Mesosilver product was more toxic than the NM-300. Bacterial viability and the physiological status (O2 uptake measured by respirometry) of the microbial community in the microcosm was negatively affected at an initial concentration of 1 mg L-1 NM-300. The high chloride concentrations in the media/seawater led to the formation of silver-chloro complexes thus enhancing AgNP toxicity. We recommend the use of natural marine bacteria as models when assessing the environmental relevant antibacterial properties of products containing nanosilver.

Biodiversity characterisation and hydrodynamic consequences of marine fouling communities on marine renewable energy infrastructure in the Orkney Islands Archipelago, Scotland, UK.

As part of ongoing commitments to produce electricity from renewable energy sources in Scotland, Orkney waters have been targeted for potential large-scale deployment of wave and tidal energy converting devices. Orkney has a well-developed infrastructure supporting the marine energy industry; recently enhanced by the construction of additional piers. A major concern to marine industries is biofouling on submerged structures, including energy converters and measurement instrumentation. In this study, the marine energy infrastructure and instrumentation were surveyed to characterise the biofouling. Fouling communities varied between deployment habitats; key species were identified allowing recommendations for scheduling device maintenance and preventing spread of invasive organisms. A method to measure the impact of biofouling on hydrodynamic response is described and applied to data from a wave-monitoring buoy deployed at a test site in Orkney. The results are discussed in relation to the accuracy of the measurement resources for power generation. Further applications are suggested for future testing in other scenarios, including tidal energy.

Commercially important species associated with horse mussel (Modiolus modiolus) biogenic reefs: A priority habitat for nature conservation and fisheries benefits.

Horse mussel reefs (Modiolus modiolus) are biodiversity hotspots afforded protection by Marine Protected Areas (MPAs) in the NE Atlantic. In this study, horse mussel reefs, cobble habitats and sandy habitats were assessed using underwater visual census and drop-down video techniques in three UK regions. Megafauna were enumerated, differences in community composition and individual species abundances were analysed. Samples of conspicuous megafauna were also collected from horse mussel reefs in Orkney for stable isotope analysis. Communities of conspicuous megafauna were different between horse mussel habitats and other habitats throughout their range. Three commercially important species: whelks (Buccinum undatum), queen scallops (Aequipecten opercularis) and spider crabs (Maja brachydactyla) were significantly more abundant (by as much as 20 times) on horse mussel reefs than elsewhere. Isotopic analysis provided insights into their trophic relationship with the horse mussel reef. Protection of M. modiolus habitat can achieve biodiversity conservation objectives whilst benefiting fisheries also.

Shifts in the metabolic function of a benthic estuarine microbial community following a single pulse exposure to silver nanoparticles.

The increasing use of silver nanoparticles (AgNPs) as a biocidal agent and their potential accumulation in sediments may threaten non-target natural environmental bacterial communities. In this study a microcosm approach was established to investigate the effects of well characterized OECD AgNPs (NM-300) on the function of the bacterial community inhabiting marine estuarine sediments (salinity 31‰). The results showed that a single pulse of NM-300 AgNPs (1 mg L(-1)) that led to sediment concentrations below 6 mg Ag kg(-1) dry weight inhibited the bacterial utilization of environmentally relevant carbon substrates. As a result, the functional diversity changed, but recovered after 120 h under the experimental conditions. This microcosm study suggests that AgNPs under environmentally relevant experimental conditions can negatively affect bacterial function and provides an insight into the understanding of the bacterial community response and resilience to AgNPs exposure, important for informing relevant regulatory measures.

The substantial first impact of bottom fishing on rare biodiversity hotspots: a dilemma for evidence-based conservation.

This study describes the impact of the first passage of two types of bottom-towed fishing gear on rare protected shellfish-reefs formed by the horse mussel Modiolus modiolus (L.). One of the study sites was trawled and the other was scallop-dredged. Divers collected HD video imagery of epifauna from quadrats at the two study sites and directed infaunal samples from one site. The total number of epifaunal organisms was significantly reduced following a single pass of a trawl (90%) or scallop dredge (59%), as was the diversity of the associated community and the total number of M. modiolus at the trawled site. At both sites declines in anthozoans, hydrozoans, bivalves, echinoderms and ascidians accounted for most of the change. A year later, no recovery was evident at the trawled site and significantly fewer infaunal taxa (polychaetes, malacostracans, bivalves and ophuroids) were recorded in the trawl track. The severity of the two types of impact reflected the undisturbed status of the habitats compared to previous studies. As a 'priority habitat' the nature of the impacts described on M. modiolus communities are important to the development of conservation management policy and indicators of condition in Marine Protected Areas (EU Habitats Directive) as well as indicators of 'Good Environmental Status' under the European Union Marine Strategy Framework Directive. Conservation managers are under pressure to support decisions with good quality evidence. Elsewhere, indirect studies have shown declines of M. modiolus biogenic communities in fishing grounds. However, given the protected status of the rare habitat, premeditated demonstration of direct impact is unethical or illegal in Marine Protected Areas. This study therefore provides a unique opportunity to investigate the impact from fishing gear whilst at the same time reflecting on the dilemma of evidence-based conservation management.

Predictive habitat modelling as a tool to assess the change in distribution and extent of an OSPAR priority habitat under an increased ocean temperature scenario: consequences for marine protected area networks and management.

The aims of this study were to determine the extent and distribution of an OSPAR priority habitat under current baseline ocean temperatures; to illustrate the prospect for habitat loss under a changing ocean temperature scenario; and to demonstrate the potential application of predictive habitat mapping in "future-proofing" conservation and biodiversity management. Maxent modelling and GIS environmental envelope analysis of the biogenic bed forming species, Modiolus modiolus was carried out. The Maxent model was tested and validated using 75%/25% training/test occurrence records and validated against two sampling biases (the whole study area and a 20km buffer). The model was compared to the envelope analysis and the area under the receiver operating characteristic curve (Area Under the curve; AUC) was evaluated. The performance of the Maxent model was rated as 'good' to 'excellent' on all replicated runs and low variation in the runs was recorded from the AUC values. The extent of "most suitable", "less suitable" and "unsuitable" habitat was calculated for the baseline year (2009) and the projected increased ocean temperature scenarios (2030, 2050, 2080 and 2100). A loss of 100% of "most suitable" habitat was reported by 2080. Maintaining a suitable level of protection of marine habitats/species of conservation importance may require management of the decline and migration rather than maintenance of present extent. Methods applied in this study provide the initial application of a plausible "conservation management tool".

Molecular variability in the Celleporella hyalina (Bryozoa; Cheilostomata) species complex: evidence for cryptic speciation from complete mitochondrial genomes.

The bryozoan Celleporella has been shown to be composed of multiple, often cryptic, lineages. We sequenced two complete mitochondrial (mt) genomes of the Celleporella hyalina species complex from Wales, UK and Norway (i) to determine genetic divergence at the complete mt genome level, and (ii) to design new molecular markers for examining the interrelationships amongst the major lineages. In addressing (i), we estimated genetic divergence at three levels: (a) nucleotide diversity (π), (b) genome size, and (c) gene order. Genes nad4L, nad6, and atp8 showed the highest levels of divergence, and rrnL, rrnS, and cox1 showed the lowest levels. Inter-genome nucleotide divergence of protein-coding and ribosomal RNA genes, measured as π, was 0.21. The two genomes differed substantially in size, with the Norwegian genome being 2,573 base pairs (bp) longer than the Welsh genome, 17,265 and 14,692 bp, respectively. This difference in size is attributable to long non-coding regions present in the Norwegian genome. Both genomes exhibit similar gene orders, except for the translocation of one transfer RNA (trnA). Considering the high nucleotide diversity, genome size difference and change in gene order, these mt genomes are considered sufficiently divergent to have originated from two distinct species. In addressing (ii) we designed PCR primers that flank the most conserved regions of the genome: 1,300 bp of cox1 and a contiguous 2,000 bp fragment of rrnL + rrnS. The primers have yielded products for tissue from Wales, Norway, New Zealand, Alaska and Chile and should provide useful tools in establishing species- and population-level diversity within the Celleporella complex.

First molecular estimate of cyclostome bryozoan phylogeny confirms extensive homoplasy among skeletal characters used in traditional taxonomy.

The Cyclostomata are the only extant representatives of the class Stenolaemata, an ancient group of exclusively marine bryozoans. Previous cladistic analyses of cyclostome bryozoans, based exclusively on skeletal characters, revealed extensive homoplasy amongst morphological traits. This study presents the first molecular phylogeny for Cyclostomata and confirms the previous findings of homoplasy. Almost complete lsr and ssrDNA fragments were sequenced for 22 taxa of cyclostome bryozoans, plus the outgroup (Pectinatella magnifica and Flustrellidra hispida). Three well-supported major clades were found, but their inter relationships are unclear. Suborder Tubuliporina was polyphyletic, with representatives found in all three major clades. The tubuliporine family Plagioeciidae was resolved as polyphyletic; Plagioecia grouped with Lichenoporidae and Densiporidae, whereas Entalophoroecia, Diplosolen and Cardioecia formed a paraphyletic subgroup that included Frondiporidae and Horneridae. The suborder Cerioporina was also polyphyletic; Densiporidae grouped with Plagioecia and Lichenoporidae, whereas Heteroporidae nested in a paraphyletic subgroup of tubuliporines, with the Crisiidae forming the sister-group to this clade. Cinctiporidae could not be placed unambiguously. Morphological character mapping was performed in order to find evidence favouring one of the three possible hypotheses of inter relationships of the major clades, but the results were ambiguous. This study questions the extent to which morphological characters can be used in phylogenetic studies of cyclostome bryozoans, both fossil and extant, and how far their morphology is the result of ecophenotypic plasticity and convergent evolution. The finding of numerous non-monophyletic taxa has implications for extinction rate assessment and for the use of fossil cyclostomes to calibrate molecular trees.

Bryozoan metabolites: an ecological perspective.

This Highlight covers the chemical ecology of bryozoans, primarily the ecological functions of bryozoan natural products. The Highlight is arranged taxonomically, according to the bryozoan Treatise classification (P. Bock, Bryozoa Homepage, 2006, http://bryozoa.net).

The complete mitochondrial genome of Flustrellidra hispida and the phylogenetic position of Bryozoa among the Metazoa.

The complete mitochondrial genome of Flustrellidra hispida (Bryozoa, Ctenostomata, Flustrellidridae) was sequenced using a transposon-mediated approach. All but one of the 36 genes were identified (trnS2). The genome is 13,026 bp long, being one of the smallest metazoan mitochondrial genomes sequenced to date with a unique gene order when compared to other Metazoa. The genome has an overall AT richness of 59.4%. We found seven regions of overlaps between tRNAs and protein-coding genes ranging from 2 to 11 nt, and seven regions of overlap between tRNAs, ranging from 1 to 8 nt, resulting in a total number of 46 overlapping nucleotides. Genes nad4, cox2, atp8, and nad3 are terminated by the abbreviated stop codon T and cytb is suggested to terminate on (ACT)AA; we postulate that mRNA editing is required to remove AC for TAA to be functional in terminating translation. Phylogenetic analysis of nucleotide and amino acid data place Flustrellidra in the Lophotrochozoa. DNA for this study originated from two populations resulting in a contig consisting of multiple haplotypes. Twenty-seven SNP sites were detected, the majority occurring in cox1 and nad5. With cox1 already established as a marker in bryozoan studies, we advocate the further testing of nad5.

Genetically modified organisms (GMOs) and aquaculture.

This paper reviews the nature of genetically modified organisms (GMOs), the range of aquatic species in which GMOs have been produced, the methods and target genes employed, the benefits to aquaculture, the problems attached to use of GMOs in aquatic species and the regulatory and other social frameworks surrounding them. A set of recommendations aimed at best practice is appended. This states the potential value of GMOs in aquaculture but also calls for improved knowledge particularly of sites of integration, risk analysis, progress in achieving sterility in fish for production and better dissemination of relevant information.