Swedish West Coast Research Articles

New deep-sea species of Xenoturbella and the position of Xenacoelomorpha.

The discovery of four new Xenoturbella species from deep waters of the eastern Pacific Ocean is reported here. The genus and two nominal species were described from the west coast of Sweden, but their taxonomic placement remains unstable. Limited evidence placed Xenoturbella with molluscs, but the tissues can be contaminated with prey. They were then considered deuterostomes. Further taxon sampling and analysis have grouped Xenoturbella with acoelomorphs (=Xenacoelomorpha) as sister to all other Bilateria (=Nephrozoa), or placed Xenacoelomorpha inside Deuterostomia with Ambulacraria (Hemichordata + Echinodermata). Here we describe four new species of Xenoturbella and reassess those hypotheses. A large species (>20 cm long) was found at cold-water hydrocarbon seeps at 2,890 m depth in Monterey Canyon and at 1,722 m in the Gulf of California (Mexico). A second large species (~10 cm long) also occurred at 1,722 m in the Gulf of California. The third large species (~15 cm long) was found at ~3,700 m depth near a newly discovered carbonate-hosted hydrothermal vent in the Gulf of California. Finally, a small species (~2.5 cm long), found near a whale carcass at 631 m depth in Monterey Submarine Canyon (California), resembles the two nominal species from Sweden. Analysis of whole mitochondrial genomes places the three larger species as a sister clade to the smaller Atlantic and Pacific species. Phylogenomic analyses of transcriptomic sequences support placement of Xenacoelomorpha as sister to Nephrozoa or Protostomia.

Topical Cluster – Fuel Cell Materials at Chalmers University of Technology

Chalmers University of Technology is a foundation-owned university located in Gothenburg on the Swedish west coast. With almost two thousands of employees in research and teaching Chalmers is one of the biggest universities in Sweden. Our vision, ‘Chalmers for a sustainable future', permeates all of our activities, with the aim to strengthen even more our position as an internationally leading university with regards to the future sustainable energy system, with high relevance to industry and society. For this purpose, much of our research covers energy related problems and covers the full spectrum of energy production, transport, storage, and conversion, for example. One of our key areas of strength is research on fuel cells, with about 15 research leaders active in this field, which spans all the way from curiosity driven fundamental research, through engineering technology, to applied research and development in close collaboration with the industry. This Topical Cluster gathers one review and four original research papers, all related to the ongoing fuel cell research activities being pursued at Chalmers. In particular, it provides a snapshot of some of our current research activities in this field, of both fundamental and applied character, as well as it highlights new directions of research. In particular, papers in this Topical Cluster show an overview of the key aspects, which are currently examined at Chalmers University of Technology. This includes the the structure and diffusive behavior of electrolyte materials (for both PEMFCs and SOFCs), the structure and active site of mesoporous carbon based fuel-cell catalysts, the properties of non-precious metal catalysts, as well as the issue of energy conversion in a more general sense, for example. Furthermore, the corrosion of interconnects in simulated SOFC anode environments, and the use of metallic bipolar plates in high temperature polymer membrane fuel cells (HT-PEMFC), are well addressed.

Pollutant Concentrations and Toxic Effects on the Red Alga Ceramium tenuicorne of Sediments from Natural Harbors and Small Boat Harbors on the West Coast of Sweden.

This investigation set out to analyze the toxicity of surface sediments in a number of natural harbors and small boat harbors on the west coast of Sweden. This was done with the growth inhibition method with Ceramium tenuicorne. Also, concentrations of copper (Cu), lead (Pb), zinc (Zn), irgarol, organotin compounds, and polycyclic aromatic hydrocarbons (PAHs) in the sediments were analyzed. The small boat harbors were heavily polluted by Cu, Zn, butyltins, and PAHs, and to a lesser extent by Pb. The Cu, Pb, Zn, and butyltins probably originated from their past and/or present use in antifouling paints, whereas the PAHs probably had multiple sources, including boat motor exhausts. The measured toxicity of the sediment was generally related to their Cu, Zn, and butyltin content, although other toxic substances than those analyzed here probably contributed to the toxicity in some of the harbors. The natural harbor sediments contained less pollutants and were less toxic than the small boat harbor sediments. Nevertheless, our data indicate that the boating pressure today may be high enough to produce toxic effects even in natural harbors in pristine areas. The strongest relationship between toxicity and the major pollutants was obtained when the sediment toxicity was expressed as gram wet weight per liter compared with gram dry weight per liter and gram total organic carbon per liter. Hence, for pollutants that can be elutriated with natural sea water, sediment toxicity expressed as gram wet weight per liter appears preferable.

Environmental influence on mussel (Mytilus edulis) growth – A quantile regression approach

The need for methods for sustainable management and use of coastal ecosystems has increased in the last century. A key aspect for obtaining ecologically and economically sustainable aquaculture in threatened coastal areas is the requirement of geographic information of growth and potential production capacity. Growth varies over time and space and depends on a complex pattern of interactions between the bivalve and a diverse range of environmental factors (e.g. temperature, salinity, food availability). Understanding these processes and modelling the environmental control of bivalve growth has been central in aquaculture. In contrast to the most conventional modelling techniques, quantile regression can handle cases where not all factors are measured and provide the possibility to estimate the effect at different levels of the response distribution and give therefore a more complete picture of the relationship between environmental factors and biological response. Observation of the relationships between environmental factors and growth of the bivalve Mytilus edulis revealed relationships that varied both among level of growth rate and within the range of environmental variables along the Swedish west coast. The strongest patterns were found for water oxygen concentration level which had a negative effect on growth for all oxygen levels and growth levels. However, these patterns coincided with differences in growth among periods and very little of the remaining variability within periods could be explained indicating that interactive processes masked the importance of the individual variables. By using quantile regression and local regression (LOESS) this study was able to provide valuable information on environmental factors influencing the growth of M. edulis and important insight for the development of ecosystem based management tools of aquaculture activities, its use in mitigation efforts and successful management of human use of coastal areas.

G. J. Billberg's (1833) 'On the ichthyology, and description of some new fish species of the pipefish genus Syngnathus'.

Gustaf Johan Billberg's review of ichthyology, published in Swedish in 1833 in the Linnéska samfundets handlingar, mentions 92 fish taxa at genus and species level, 41 of which represent new taxa, unnecessary replacement names, or unjustified emendations. Billberg presents his own classification of fishes, in which five new family names are introduced: Ballistidae, Diodontidae, Ooididae, Chironectidae, and Macrorhyncidae. Diodontidae has priority over Diodontidae Bonaparte, 1835. Macrorhyncidae was published earlier than Gempylidae Gill, 1862, but the latter has priority by prevailing usage. Billberg mentions 61 genera of fishes, 41 of them listed only by name. Six generic names proposed by Billberg are available as unjustified emendations: Myxinus, Petromyzus, Scylia, Mustellus, Zyganna, and Ballistes. Brachionus is an unnecessary replacement name. Aphrus, Capriscus, Exormizus, Enneophthalmus, and Oedaus are nomina nuda. Eight new genera of fishes are proposed: Anodon, Posthias, Orbis, Sphaeroides, and Ooides are junior synonyms; Cotilla is a nomen oblitum in relation to Sufflamen Jordan, 1916; Tropigaster a nomen oblitum in relation to Aracana Gray, 1835; and Tetragonizus a nomen oblitum in relation to Lactoria Jordan & Fowler, 1902. Billberg lists 31 species of fishes. Three represent new combinations; two are nomina nuda. The following 14 new species are described based on literature: Raja forskohlii, Cephaloptera dumerillii, Myliobatis lacepedei, Scylia russelii, Anodon macropterus, Cotilla frenata, Monacanthus blochii, M. sebae, M. cuvieri, M. marcgravii, Tetraodon striatus, Orbis psittacinus, Orbis punctulatus, and Orbis guttatus. All of those are invalid, except Scylia russelii, which is a species inquirenda. The following nine species group names are unnecessary replacement names and consequently invalid: Raja arabica, Myliobatis rissoi, Scylia isabellina, Anodon cirrhosus, Anodon cornutus, Zyganna voracissima, Centrina broussonetii, Acipenser vulgaris, and Acipenser ichthyocolla. Three species of pipefishes of the family Syngnathidae are described and figured by Billberg from drawings of specimens observed on the Swedish West Coast. Syngnathus virens and S. pustulatus are junior synonyms of S. typhle Linnaeus, 1758. Syngnathus palmstruchii is a junior synonym of Entelurus aequoreus (Linnaeus, 1758).

Summer mortalities and detection of ostreid herpesvirus microvariant in Pacific oyster Crassostrea gigas in Sweden and Norway.

The Pacific oyster Crassostrea gigas has recently expanded its range in Scandinavia. The expansion is presumably a result of northwards larval drift. Massive settlements were recorded in many areas along the Swedish west coast and southern Norway in 2013 and 2014. After the spawning season in 2014, the temperature of the surface water peaked at 24-26°C. After this period, high and sudden mortalities occurred in a Swedish hatchery and in wild populations along the Swedish west coast and south coast of Norway. Surveys and collected data showed that mortalities mainly occurred during 3 wk in September. All size classes were affected, and affected populations displayed a patchy distribution with heavily affected and unaffected populations in close proximity. Flat oysters Ostrea edulis and blue mussels Mytilus edulis were unaffected. Ostreid herpesvirus (OsHV) was detected in moribund Pacific oyster spat as well as in surviving adults. The virus was identified as OsHV-1 μvar. This is the first detection of this variant in Scandinavia, showing that OsHV-1 μvar is present in areas with recent establishments of Pacific oysters, and where there is no aquaculture of this species.

Modeling and predicting the growth of the mussel, Mytilus edulis: implications for planning of aquaculture and eutrophication mitigation.

The increased pressure on the marine ecosystems highlights the need for policies and integrated approaches for sustainable management of coastal areas. Spatial planning based on geographic information of human activities, ecological structures and functions, and their associated goods and services is a fundamental component in this context. Here, we evaluate the potential of predictive modeling to provide spatial data on one ecosystem function, mussel growth for use in such processes. We developed a methodology based on statistical modeling, spatial prediction, and mapping for the relative growth of the blue mussel, Mytilus edulis. We evaluated the performance of different modeling techniques and classification schemes using empirical measurements of growth from 144 sampling sites and data on biological, chemical, and physical predictors. Following comparisons of the different techniques and schemes, we developed random forest models to predict growth along the Swedish west coast. Implemented into GIS the best model produced in this study predicts that low, intermediate, and high growth rates can be expected in 53%, 32%, and 15% of modeled area, respectively. The results of this study also suggest that the nature and quality of predictor data hold the key to improving the predictive power of models. On a more general note, this study exemplifies a feasible approach based on measuring, modeling, and mapping for obtaining scientifically based spatial information on ecosystem functions and services affected by a complex set of factors. Such information is fundamental for maritime spatial planning and ecosystem-based management and its importance is likely to increase in the future. Because of its close link to nutrient assimilation and production yield, site-specific information of soft tissue growth such as the map of predicted growth rate developed in this study can be used as a tool for optimizing actions aimed at mitigating eutrophication and aquaculture operations and in maritime spatial planning processes of coastal areas.

BMAA detected as neither free nor protein bound amino acid in blue mussels

The results of this study imply that β-methylamino-alanine (BMAA) obtained from extracts of blue mussels from the Swedish west coast is neither free nor protein bound. The results were obtained by separation (precipitation and ultrafiltration) of low and high molecular weight compounds from neutral extracts of blue mussels, and treatment of these extracts with low and high concentrations of acids, varying time and temperature. The main portion of BMAA was obtained from the low molecular weight fraction, released or formed at 95 °C in dilute acids. The measured amount of BMAA did not increase by strong acid treatment. Lysine was used as reference and was only released at significant amounts when treating the high molecular weight fraction with concentrated acid. The results also indicated that breakage of peptide bonds was not involved in the formation/release of BMAA in these extracts unless any BMAA peptide bond would be significantly more susceptible to dilute acid than e.g. the monitored lysine peptide bond. BMAA was measured using isotope dilution and detection of the underivatized compound by HILIC–UHPLC–MS/MS (Hydrophilic Interaction Liquid Chromatography, Ultra-High Performance Liquid Chromatography, tandem Mass Spectrometry). The findings might add to the understanding of conflicting data in the literature regarding the occurrence of BMAA, and have implications for studies on possible biomagnification of BMAA in the food chain and bioavailability from food.

Seasonal and spatial variation in biochemical composition of Saccharina latissima during a potential harvesting season for Western Sweden

Abstract This study monitored the biomass composition of Saccharina latissima during a potential harvesting season on the West coast of Sweden, in order to find suitable harvest times for biorefinery purposes. Specimens of S. latissima were sampled at three locations in June, August and October and the biomass was analysed for its macromolecular composition, as well as for the content of several specific compounds, e.g. sugars and fatty acids. PERMANOVA analyses showed that there was a significant difference in the biomass composition among time points. The total carbohydrate concentration was lowest in June and peaked at 360 mg g-1 dry weight in August, while the mannitol content was highest, 90 mg g-1, in June and decreased throughout the sampling period. Total protein and fatty acid concentrations were found to be approximately 80 and 3 mg g-1, respectively, with relatively little variation over time. Overall, there was little spatial variation in the macromolecular composition, although the concentration of some specific monosaccharides and fatty acids, as well as the total phenolic content, differed among localities. We discuss the implications of the observed variation in biomass composition of S. latissima for future biorefinery purposes.

Study of the foundation design for a linear generator wave energy converter using stochastic methods

This paper presents design studies of the gravity-based foundation for a linear generator wave energy converter. The wave energy converter is based on a direct driven generator mounted on the gravity-based foundation located at the seabed. The linear generator is connected to a point absorbing buoy on the sea surface via a connection rope. Such a device, developed at Uppsala University, has been in operation on the Swedish west coast since 2006. Study is focused on the analysis of the impact from undesirable motions of the gravity-based foundation, particularly the study of the tip and lifts phenomena with regard to the heave and surge forces. Long-term extreme significant wave heights are extrapolated from the statistical analysis of the measured wave climate data in the test site where the wave energy converter is deployed. The joint distribution of the significant wave height and the zero-crossing period from the measured wave climate is also analyzed to estimate the associated periods with respect to the long-term extreme significant wave height. The 25 years return extreme significant wave height 4.8 m which is associated with its mean zero-crossing period 8.25 s from the joint distribution is chosen to determine the characteristics of the possible maximum wave for the Lysekil test site. The estimated maximum wave 9.2 m is used to estimate the extreme values of the heave and surge forces on the wave energy converter and the gravity-based foundation. The results with respect to the foundation of a new generation wave energy converter about 35 tons with the presented methodology indicate that a heavier foundation which is about 70 tons needs to be designed in terms of considering the stability of the mooring foundation for long term real sea operation. The purpose of this paper is to propose a reliable approach to estimate the appropriate dimensions for gravity-based foundation of the linear generator wave energy converter and provides a theoretical reference to the construction of the gravity-based foundation.

Metagenomic sequencing of marine periphyton: taxonomic and functional insights into biofilm communities.

Periphyton communities are complex phototrophic, multispecies biofilms that develop on surfaces in aquatic environments. These communities harbor a large diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans, and metazoans. However, thus far the total biodiversity of periphyton has not been described. In this study, we use metagenomics to characterize periphyton communities from the marine environment of the Swedish west coast. Although we found approximately ten times more eukaryotic rRNA marker gene sequences compared to prokaryotic, the whole metagenome-based similarity searches showed that bacteria constitute the most abundant phyla in these biofilms. We show that marine periphyton encompass a range of heterotrophic and phototrophic organisms. Heterotrophic bacteria, including the majority of proteobacterial clades and Bacteroidetes, and eukaryotic macro-invertebrates were found to dominate periphyton. The phototrophic groups comprise Cyanobacteria and the alpha-proteobacterial genus Roseobacter, followed by different micro- and macro-algae. We also assess the metabolic pathways that predispose these communities to an attached lifestyle. Functional indicators of the biofilm form of life in periphyton involve genes coding for enzymes that catalyze the production and degradation of extracellular polymeric substances, mainly in the form of complex sugars such as starch and glycogen-like meshes together with chitin. Genes for 278 different transporter proteins were detected in the metagenome, constituting the most abundant protein complexes. Finally, genes encoding enzymes that participate in anaerobic pathways, such as denitrification and methanogenesis, were detected suggesting the presence of anaerobic or low-oxygen micro-zones within the biofilms.

Description of Aegialoalaimus bratteni sp. n. from Skagerrak and a review of the genus (Aegialoalaimidae, Nematoda incertae sedis).

BackgroundThe genus Aegialoalaimus de Man, 1907 includes 12 nominal species, of which three species are considered valid, two species were transferred to other genera and seven species have uncertain taxonomic status.New informationNew species, Aegialoalaimus bratteni sp. n. was found in Skagerrak off the west coast of Sweden. It is particularly characterized by the 1.5-1.8 mm long body, short papilliform cephalic sensilla, excretory pore opening just posterior to nerve ring level, spicules that are straight in shape, supplements and gubernaculum absent, separating it from other valid species of the genus. It can be further differentiated from Aegialoalaimus elegans in having longer body (1.5-1.8 mm in A. bratteni sp. n. vs 0.8-1.3 mm in A. elegans), shape and size of spicules (straight and 22-29 µm long in A. bratteni sp. n. vs arcuate and 34 µm long in A. elegans), absence of precloacal supplements (vs seven-eight in A. elegans), absence of gubernaculum (vs present in A. elegans); from A. setosa in having shorter tail (c´=2.6-3.1 in A. bratteni sp. n. vs c´=4.2 in A. setosa), shorter cephalic sensilla (0.5-1.0 µm in A. bratteni sp. n. vs 9 µm in A. setosa), shape and size of spicules (straight and 22-29 µm long in A. bratteni sp. n. vs arcuate and 40-45 µm long in A. setosa), absence of precloacal supplements (vs eight in A. setosa), absence of gubernaculum (vs present in A. setosa); from A. leptosoma in having longer body (1.5-1.8 mm in A. bratteni sp. n. vs 0.5-0.7 mm in A. leptosoma) and other measurements, shape of spicules (straight in A. bratteni sp. n. vs arcuate in A. leptosoma), absence of precloacal supplements (vs three-five in A. leptosoma), absence of gubernaculum (vs present in A. leptosoma). Type specimens of Aegialoalaimus cylindricauda Allgén, 1933 and A. paratenuicaudatus Allgén, 1959 are redescribed and taxonomic status of these two species is re-evaluated. A taxonomic review, tabular compendium and identification key for species of the genus Aegialoalaimus are also given.

What is Xenoturbella?

Xenoturbella is a strange marine worm that can be collected regularly only off the west coast of Sweden. Due to its simple morphology, which lacks a centralized nervous system, coelom, anus, or reproductive organs, its phylogenetic position has long remained obscure. Recent phylogenomic analyses suggest it forms a new phylum, Xenacoelomorpha, together with the Acoelomorpha, but the position of the phylum remains undecided, either as a deuterostome or an early branching bilaterian. Developmental stages exhibit many phylogenetically decisive characters in various animal species, but have remained a mystery for Xenoturbella until recently. Observations of its development showed it has direct development with a very short and simple swimming stage, and that it lacks a feeding larva. Asexual reproduction has never been reported. It has been suggested that Xenoturbella feeds specifically on bivalves, but it still remains unknown whether it feeds on sperm, eggs, larvae, juveniles, carcass, mucus, or feces of bivalves, and direct observations of Xenoturbella feeding on bivalves have not been reported. Endosymbiont bacteria have been found, and their functions are being investigated. The evolutionary scenario of this taxon remains the subject of debate, and our understanding will depend largely on determining its phylogeny. Thus, although recent studies have uncovered many new and crucial facts regarding Xenoturbella, some fundamental biological information, such as phylogeny, complete life cycle, and genome, remain unsolved. Further research on the well-studied Swedish Xenoturbella bocki, as well as the discovery of new species elsewhere, are necessary if we are to more fully understand the nature of Xenoturbella.

Tardigrades of Sweden; an updated check-list.

Tardigrades occur worldwide and in a variety of ecosystems and habitats representing an important component of the micrometazoan biodiversity. Several studies documenting the occurrence of tardigrades in Sweden have been published since the first reports in early 1900, but no comprehensive summary of these studies have been published. We compiled the available information on recorded tardigrades from Sweden, using material from published studies and museum and university collections. In total, our review document 101 species of tardigrades that have been recorded from Sweden (an updated checklist of tardigrades from Sweden will be available online), of which 14 species are new records for the country. The highest number of species was recorded in the northernmost province of Lappland and the more southern provinces of Uppland and Skåne, while much lower species numbers are reported from the middle part of Sweden. This pattern probably represents biased sampling activities of biologists rather than real differences in biodiversity of tardigrades. In view of the few studies that have been made on tardigrade biodiversity in Sweden, the relatively high number of tardigrade species recorded, representing almost a tenth of the species recorded worldwide, indicates that many more species remain to be found. In this respect, more studies of the marine ecosystems along the Swedish west coast and the long Baltic Sea coastline would be of particular interest.

The use of at‐sea‐sampling data to dissociate environmental variability in Norway lobster (Nephrops norvegicus) catches to improve resource exploitation efficiency within the Skagerrak/Kattegat trawl fishery

AbstractResearch into the influence of environmental variables on the behaviour of Norway lobster (Nephrops norvegicus), and hence catch rates, dates back to the 1960s (e.g., Höglund and Dybern, Diurnal and seasonal variations in the catch‐composition of Nephrops norvegicus (L.) at the Swedish west coast. ICES CM 1965/I46; Simpson, Variations in the catches of Nephrops norvegicus at different times of day and night. Rapport et Proés‐verbaux des Réunions Conseil permanent international pour 1'Exploration de la Mer 156:186). However, the use of fishery‐dependent data in identifying influential factors is relatively limited and only includes a number of papers on a limited dataset (e.g., Redant and De Clark, Diurnal variations in CPUE and length composition of the catches in a Nephrops directed fishery in the Central North Sea. ICES CM 1984/K:3; Maynou and Sardà, Influence of environmental factors on commercial trawl catches of Nephrops norvegicus (L.). ICES J. Mar. Sci. 58:1318). Here, we aimed to dissociate environmental variability in Norway lobster catches to improve resource exploitation efficiency within the Skagerrak and Kattegat trawl fisheries by utilising data collected as part of an extensive at‐sea‐sampling programme spanning 16 years. Catch rates were modelled using Generalized Additive Mixed Models (GAMMs) and considered a range of response variables, including depth, temperature, current speed, season, moon phase and time of day. The results obtained herein showed that time of day, season, depth, temperature, year, trawl type and location all significantly affect catch rates of Nephrops.

A gene to organism approach--assessing the impact of environmental pollution in eelpout (Zoarces viviparus) females and larvae.

A broad biomarker approach was applied to study the effects of marine pollution along the Swedish west coast using the teleost eelpout (Zoarces viviparus) as the sentinel species. Measurements were performed on different biological levels, from the molecular to the organismal, including measurements of messenger RNA (mRNA), proteins, cellular and tissue changes, and reproductive success. Results revealed that eelpout captured in Stenungsund had significantly higher hepatic ethoxyresorufin O‐deethylase activity, high levels of both cytochrome P4501A and diablo homolog mRNA, and high prevalence of dead larvae and nuclear damage in erythrocytes. Eelpout collected in Göteborg harbor displayed extensive macrovesicular steatosis, whereby the majority of hepatocytes were affected throughout the liver, which could indicate an effect on lipid metabolism. Results also indicate that eelpouts collected at polluted sites might have an affected immune system, with lower mRNA expression of genes involved in the innate immune system and a higher number of lymphocytes. Biomarker assessment also was performed on livers dissected from unborn eelpout larvae collected from the ovary of the females. No significant differences were noted, which might indicate that the larvae to some extent are protected from effects of environmental pollutants. In conclusion, usage of the selected set of biological markers, covering responses from gene to organism, has demonstrated site‐specific biomarker patterns that provided a broad and comprehensive picture of the impact of environmental stressors. Environ Toxicol Chem 2015;34:1511–1523. © 2015 The Authors. Published by SETAC.

Swedish Plectida (Nematoda). Part 9. The genus Leptolaimoides Vitiello, 1971.

Three known and two new species of Leptolaimoides are described from bottom sediments collected in Skagerrak off the west coast of Sweden. The following known species are redescribed: Leptolaimoides haploopis Jensen, 1978, L. tubulosus Vitiello, 1971 and L. hexatubulosus Hoang Lai-Phu et al., 2009. Leptolaimoides filicaudatus sp. n. is characterised by the 431-543 µm long body; cephalic sensilla papilliform; amphid 23-26 µm long, located 9-10 µm from anterior end; first body pore located 35-37 µm from anterior end; lateral field simple along most of body, areolated on tail, arising 36-40 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubular and without alveolar supplements; spicules arcuate and 16 µm long. Leptolaimoides leptomicron sp. n. is characterised by the 776-847 µm long body; cephalic sensilla papilliform; amphid 15-17 µm long, located 9-13 µm from anterior end; first body pore located 40-46 µm from anterior end; lateral field areolated, arising 26-28 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with three tubular and without alveolar supplements, spicules arcuate and 28-29 µm long. The diagnosis of the genus Leptolaimoides is emended and a tabular compendium and dichotomous identification key to species of the genus Leptolaimoides are provided.

Early Colonization, Glacial Melt Water, and Island Mass Effect in the Archipelago of Western Sweden: A Case History

SummaryIn this short article I consider the relationship between glacial melt water that empties into the sea, and early coastal colonization by hunter‐gatherers. In addition, I contend that this archaeological/oceanographical case study from the Swedish west coast is a model that can be applied to other coastal areas of the world with raised beaches, and where similar conditions prevailed during the close of the Late Glacial and the beginning of the early Post Glacial.

Low MHC variation in isolated island populations of the Natterjack toad (Bufo calamita)

We studied variation at the class II gene of the major histocompatibility complex (MHC) in Natterjack toad populations (Bufo [Epidalea] calamita) on islands off the west coast of Sweden. These isolated populations have previously been shown to exhibit low levels of neutral genetic variation. On seven investigated islands we found only two different MHC alleles, indicating that the genetic variation at this locus is also low. The two alleles were found in all populations, although in one population there was only a single heterozygous individual. The Swedish toads showed similar low levels of MHC variation as revealed by previously published data from populations in northern Europe. We did not find a correlation between MHC and neutral genetic variation (as determined by AFLP). However, our findings show that reduced genetic variation in the Swedish Natterjack toads is not restricted to neutral markers, but is likewise reflected at the MHC.

Optimizing wave energy parks with over 1000 interacting point-absorbers using an approximate analytical method

Large arrays of wave energy converters of point-absorber type are studied using an approximate analytical model. The model is validated against a numerical method that takes into account full hydrodynamic interactions based on linear potential flow theory. The low computational cost of the analytical model enables parameter studies of parks in the MW range and includes up to over 1000 interacting devices. The model is actuated by irregular wave data obtained at the Swedish west coast. In particular, focus is on comparing park geometries and improving park configurations to minimize the power fluctuations.