Differences in the species- and size-composition of fish assemblages in three distinct seagrass habitats with differing plant and meadow structure

Fish faunas were sampled seasonally using a large and a small beam trawl in three seagrass habitats comprising predominantly Amphibolis griffithii or Posidonia sinuosa or Posidonia coriacea, which differ in seagrass and meadow structure. Amphibolis griffithii and P. sinuosa both produce a relatively dense leaf canopy, but the former exhibits a distinct architecture, with the leaf canopy overlying relatively open spaces surrounding woody stems, compared to the uniformly dense blade-like leaves of P. sinuosa which emerge directly from the sediment. In comparison, P. coriacea provides a landscape of patchy seagrass amongst areas of bare sand. Since the latter seagrass habitat contains large areas of sand, fish were also sampled in adjacent unvegetated areas. The number of species and density of fish were greater (P<0.05) in P. sinuosa than in either A. griffithii or P. coriacea. The mean number of species caught using the large trawl ranged from 16 to 24 in the first of these habitats compared to 14–21 and 9–15 in the last two habitats, respectively, and the mean densities ranged between 78 and 291 fish 1000 m^?2 in P. sinuosa compared to 31–59 fish 1000 m^?2 in A. griffithii and 31–59 fish 1000 m^?2 in P. coriacea. The biomass of fish was greater (P<0.05) in both P. sinuosa and A. griffithii than in P. coriacea (4.2–5.3 kg and 3.3–6.2 kg versus 0.7–1.9 kg 1000 m^?2, respectively). Furthermore, the size-structure of fish differed among these habitats, where the median weight of fish was 72.1 g in A. griffithii, compared to 7.5 g and 19.8 g in P. sinuosa and P. coriacea, respectively. Ordination and ANOSIM demonstrated that the species-composition differed markedly among the three seagrass habitats (P<0.001), suggesting that fish species display a distinct preference for particular seagrasses characterised by different architecture. Differences in species-composition among the seagrass habitats partly reflected the size-composition of fish in each habitat. The open space below the canopy of A. griffthii is likely to allow larger fish to occupy this habitat, whereas only small fish would be able to penetrate the dense foliage of P. sinuosa. Differences in species- and size-composition of fish among these habitats may be the result of settlement-sized larvae discriminating between particular seagrass and meadow structures, or fish being subject to different levels of predation and/or accessibility to food or space. The species-composition in P. coriacea was highly dispersed and did not differ from that of unvegetated areas. While several species were associated with both P. coriacea and bare-sand habitats, some species did display a high affinity with the seagrass P. coriacea. This may reflect an association with the sparse and narrower leaves of this seagrass or with the patchy occurrence of the seagrass Heterozostera tasmanica, which commonly occurs as an understorey in this habitat.     

Phytotoxic effects of phenolic acids from <Emphasis Type="Italic">Merostachys riedeliana,</Emphasis> a native and overabundant Brazilian bamboo

Merostachys riedeliana Rupr. is a native and overabundant bamboo species in the Brazilian Atlantic Forest. Moderate to strong allelopathic activity may be one mechanism that explains this super-dominance and the changes in structure and composition of forest areas occupied by bamboo. This study evaluated the phytotoxic effect of M. riedeliana extracts and fractions and identified their putative allelochemicals. We investigated the presence of allelochemicals in soil collected from stands occupied by M. riedeliana. Furthermore, we evaluated the putative effect of tree allelochemicals, individually and combined, on germination and growth. The aqueous extract of leaves and its ethyl acetate fraction presented the highest inhibitory effects on seed germination and seedling growth. The effect of the extracts and fractions on the target species was species-specific. Neither the individual nor the combined phenolic acids significantly inhibited seed germination; however, a pronounced growth inhibition was observed in M. bimucronata seedlings treated with vanillic acid and in E. verna and M. bimucronata seedlings treated with combined phenolic acids. Isovitexin, vitexin, isoorientin, orientin, and their O-glycoside derivatives, the lactonic dimer of the p-hydroxybenzoic acid and 3,4-methylenedioxymandelic acid were identified in the aqueous extracts and ethyl acetate fraction by Liquid Chromatography-Diode Array Dectector/Electrospray Ionization/Mass Spectrometry (LC-DAD/ESI–MS/MS). The Gas Chromatography-Mass Spectrometer (GC–MS) profile of the same extract and fraction showed the presence of benzoic, benzeneacetic, salicylic, p-hydroxybenzoic, p-hydroxyphenylacetic, vanillic, p-coumaric, protocatechuic, syringic, gallic, m-coumaric vanillylmandelic, 4-methylmandelic, 3,4-methylenedioxymandelic and trans-ferulic acids. The p-benzoic acid and the apigenin 6-C-glucoside (isovitexin) were identified in the soil extract collected from under bamboo-growing areas. Even though laboratory bioassays are not completely predictive of the allelopathic effects that occur in nature, the results of this study provide preliminary evidence of allelopathy as a possible species-specific inhibition mechanism of native species that explain the impoverishment of floristic richness and the functional groups in areas where M. riedeliana is overabundant.     

Developmental and genetic evidence for the existence of three morphologically cryptic species of<Emphasis Type="Italic"> Crepidula</Emphasis> in northern Chile

The taxonomy of Crepidula has been based principally on shell morphology, but shell characteristics in this genus may be strongly influenced by the substrates they inhabit and are thus of limited use in classification. Four species in this genus are currently recognized from the Chilean coast, of which two, Crepidula dilatata and C. fecunda, are sympatric. These species are morphologically cryptic and differ only in their larval development: C. dilatata has indirect development with a planktonic phase, and C. fecunda direct development within egg capsules. The other two species, C. coquimbensis and C. philippiana, are species that occur within gastropod shells inhabited by hermit crabs and differ from the other species in internal morphology of the shell, developmental features, and geographic distribution. Analyses of nine morphological characters, eight developmental characters, and 26 enzymatic loci were carried out on four Crepidula populations in the Coquimbo region of northern Chile. Four populations of Crepidula were identified based on morphological, developmental, and protein electrophoresis features. Our results suggest the presence of C. coquimbensis plus three morphologically cryptic species including C. dilatata, C. fecunda, and a new previously unrecognized cryptic species. All four populations showed differences in larval development pattern. C. fecunda have indirect development, with free-swimming larvae. The remaining three species have intracapsular metamorphosis, but different modes of larval nutrition. C. dilatata have nurse eggs that are consumed by mechanical destruction; C. coquimbensis engulf nutritional embryos; and the new species eat nutritive embryos by rotation. Protein electrophoresis data support the specific condition of each group with different larval development and endorse the use of developmental differences in taxonomy of Crepidula. Genetic distance shows that C. dilatata and C. fecunda are closely related, and that C. coquimbensis is closer to them than to the new cryptic species.     

Impact of logging activities in a tropical mangrove on ecosystem diversity and sediment heavy metal concentrations

Productivity of mangrove ecosystems is compromised by anthropogenic activities including over-exploitation of wood. This study set out to understand how different wood harvesting regimes have affected the biodiversity of a tropical ecosystem and to identify relationships between the heavy metal concentrations in the mangrove sediments and tree felling. Soil samples were collected and plant diversity studies carried out on seven sites in the mangrove. Physico-chemical, chemical and mineralogical analyses were done on soil samples and plant population structure, species richness, evenness and diversity index at these sites were calculated. Results showed that soils across sites were characteristically clayey and acidic, with high organic matter content. Minerals identified included quartz, gibbsite, goethite, hematite and kaolinite. Heavy metal concentrations were higher in Sites 6 and 7 with a longer history of anthropogenic activity. There were strong negative correlations between the duration of logging and NO₃-N (r = ?0.838, p = 0.019), total N (r = ?0.837, p = 0.019), NH₄ ⁺-N (r = ?0.844, p = 0.017), Mg = (?0.789, p = 0.035), K (r = ?0.819, p = 0.024), and Na (r = ?0.988, p = 0.002). Sites which had experienced logging for longer periods (sites 3, 6, and 7) had lower nutrient content and lower values for species richness and diversity index. Logging in mangrove ecosystems could alter soil characteristics, decreasing plant diversity and abundance. Logging dynamics around mangrove ecosystems should be considered in the wider strategy for management and conservation of similar mangrove ecosystems.     

Variation in fertilisation abilities between hemiclonal hybrid and sexual parental males of sympatric water frogs (<Emphasis Type="Italic">Rana lessonae</Emphasis>,<Emphasis Type="Italic"> R. esculenta</Emphasis>,<Emphasis Type="Italic"> R. ridibunda</Emphasis>)

In many species, males and females mate with multiple partners, which gives rise to sperm competition and multiple paternity. The experiments on water frogs presented here demonstrate that such sperm competition can affect the structure and dynamics of mixed-species communities. The hybrid frog Rana esculenta (LR) mates with one of its parental species, usually R. lessonae (LL), although in some areas R. ridibunda (RR), to regain the premeiotically eliminated parental genome ("hybridogenesis"). Mixed LL/LR-populations are stable although hybrid numbers should continuously increase at the expense of parental animals, because of differences in female fecundity and other factors. This would finally lead to the extinction of the sexual host, followed by that of the sexual parasite, unless the reproductive superiority of R. esculenta is reduced by other factors, such as lower hybrid male fertility. Eggs from LL- and LR-females were fertilised in vitro by single- and multi-male sperm suspensions of LL-, LR- and RR-males. In all experiments, the proportion of offspring sired by R. esculenta sperm was significantly lower than that sired by R. lessonae or R. ridibunda sperm. Gonad mass, sperm morphology, sperm swimming velocity, and sperm survival did not explain these differences in fertilisation success; nor did gamete recognition and compatibility. Sperm density was the only trait that paralleled fertilisation success, but it offers no explanation either, because densities were equalised for the in-vitro fertilisations. In natural LL/LR populations, the significantly smaller amount, poorer competitive ability and lower long-term survival of R. esculenta compared to R. lessonae sperm will reduce the initial reproductive superiority of hybrids and contribute to the stabilisation of mixed water-frog populations. Differences in fertilisation ability are also likely to be relevant for the structure and dynamics of several other systems with encounters between eggs and sperm from different genotypes, ecotypes, ploidy levels and/or species.     

Microbial responses to combined oxidation and catalysis treatment of 1,4-dioxane and co-contaminants in groundwater and soil

Post-treatment impacts of a novel combined hydrogen peroxide (H₂O₂) oxidation and WO_x/ZrO₂ catalysis used for the removal of 1,4-dioxane and chlorinated volatile organic compound (CVOC) contaminants were investigated in soil and groundwater microbial community. This treatment train removed ~90% 1,4-dioxane regardless of initial concentrations of 1,4-dioxane and CVOCs. The Illumina Miseq platform and bioinformatics were used to study the changes to microbial community structure. This approach determined that dynamic shifts of microbiomes were associated with conditions specific to treatments as well as 1,4-dioxane and CVOCs mixtures. The biodiversity was observed to decrease only after oxidation under conditions that included high levels of 1,4-dioxane and CVOCs, but increased when 1,4-dioxane was present without CVOCs. WO_x/ZrO₂ catalysis reduced biodiversity across all conditions. Taxonomic classification demonstrated oxidative tolerance for members of the genera Massilia and Rhodococcus, while catalyst tolerance was observed for members of the genera Sphingomonas and Devosia. Linear discriminant analysis effect size was a useful statistical tool to highlight representative microbes, while the multidimensional analysis elucidated the separation of microbiomes under the low 1,4-dioxane-only condition from all other conditions containing CVOCs, as well as the differences of microbial population among original, post-oxidation, and post-catalysis states. The results of this study enhance our understanding of microbial community responses to a promising chemical treatment train, and the metagenomic analysis will help practitioners predict the microbial community status during the post-treatment period, which may have consequences for long-term management strategies that include additional biodegradation treatment or natural attenuation.

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Arsenic,antimony, and other trace element contamination in a mine tailings affected area and uptake by tolerant plant species

The study was conducted to characterize mineralogical and elemental composition of mine tailings in order to evaluate the environmental hazards, and identify the metal accumulation potential of native plant species from São Domingos mine, one of the long-term activity mines of the Iberian Pyrite Belt dating back to pre-Roman times. The mine tailings including soils and different plant species from São Domingos were analyzed for determination of tailings characteristics and chemical element contents in tailings and plants. The large amounts of mining wastes are causing significant adverse environment impacts due to acid mine drainage production and mobilization of potentially toxic metals and metalloids in residential areas, agricultural fields, downstreams, and rivers. The typical mineralogical composition is as follows: quartz, micas, K-feldspar, olivine-group minerals, magnetite, goethite, hematite, jarosite, and sulfides. The mine tailings were highly contaminated by As, Ag, Cr, Hg, Sn, Sb, Fe, and Zn; and among them, As and Sb, main contaminants, attained the highest concentrations except Fe. Arsenic has exhibited very good correlations with Au, Fe, Sb, Se, and W; and Sb with As, Au, Fe, Se, Sn, and W in tailings. Among the all plant species, the higher concentrations of all the metals were noted in Erica andevalensis, Erica australis, Echium plantagium, and Lavandula luisierra. Considering the tolerant behavior and abundant growth, the plant species Erica australis, Erica andevalensis, Lavandula luisierra, Daphne gnidium, Rumex induratus, Ulex eriocladus, Juncus, and Genista hirsutus are of major importance for the rehabilitation and recovery of degraded São Domingos mining area.     

Multiple lineages and absence of panmixia in the “circumpolar” crinoid <Emphasis Type="Italic">Promachocrinus kerguelensis</Emphasis> from the Atlantic sector of Antarctica

Despite considerable interest in physiology, evolution and life history of Antarctic marine invertebrates, only a limited number of studies have examined the genetic variability and diversity patterns of these organisms. Moreover, understanding and characterizing patterns of Antarctic biodiversity has taken on a degree of urgency because of potential impacts of global warming. To expand an understanding of the evolutionary history of Antarctic marine invertebrates, the genetic diversity of the crinoid Promachocrinuskerguelensis Carpenter, 1888 was investigated, which is documented to have a circumpolar distribution extending to subantarctic islands. Specimens of P. kerguelensis were collected from the western side of the Antarctic Peninsula, and the subantarctic islands South Georgia, South Sandwich and Bouvetøya Island from 2001 to 2004. P. kerguelensis was previously subject to morphological review that confirmed the taxonomic recognition of only one species. The wide distribution and reported high dispersal capability for P. kerguelensis predicts one large panmictic population. In contrast, nucleotide sequence data from mitochondrial cytochrome oxidase subunit I and cytochrome b genes, collected herein, reveal distinct genetic structure and cryptic speciation within P.kerguelensis. In the Antarctic Atlantic sector alone, there were at least five “species-level” clades. Some of these clades are geographically limited, and most exist in sympatry. The largest and most widespread of these clades was examined to help elucidate connectivity along the subantarctic islands of the Scotia Arc and the Antarctic Peninsula. Within this clade, most genetic diversity was contained within populations, but significant differences were present between regions (Antarctic Peninsula, South Sandwich Is., South Georgia, Bouvetøya Is.), suggesting a corresponding lack of gene flow. Given that P. “kerguelensis” is a well-studied taxon, the finding of considerable genetic diversity within the Atlantic sector alone suggests that the recognized diversity of Antarctica’s benthic marine life may be underestimated, and will rise dramatically with phylogeographic analyses of putative widespread species.     

A population comparison of the strength and persistence of innate colour preference and learning speed in the bumblebee <Emphasis Type="Italic">Bombus terrestris</Emphasis>

Studies of innate colour preference and learning ability have focused on differences at the species level, rather than variation among populations of a single species. Initial strength and persistence of colour preferences are likely to affect colour choices of naïve flower visitors. We therefore study the influence of both the strength and persistence of innate colour preference (for blue) on an operant learning task (associating food reward with yellow flowers) in two populations of the bumblebee Bombus terrestris. We found that both strength and persistence of blue preference differed significantly between populations: B. terrestris dalmatinus had a weaker and less persistent blue preference than B. terrestris audax. These differences in preference also influenced learning performance. Considering only landing behaviours, one-trial learning occurred in the majority (73%) of bees, and was achieved sooner in B. terrestris dalmatinus because of its weaker blue preference. However, compared to landing behaviours the relative frequency of approach flights to rewarding and unrewarding flower types changed more slowly with task experience in both populations. When considering both approaches and landings, the rate of learning, following the first rewarded learning trial, was faster in B. terrestris audax than B. terrestris dalmatinus. However, the net effects of population differences in blue preference and learning dynamics result in similar final levels of task performance. Our results provide new evidence of behavioural differences among isolated populations within a single species, and raise intriguing questions about the ecological significance and adaptive nature of colour preference.     

Physiological adaptations of the invasive cordgrass<Emphasis Type="Italic"> Spartina anglica</Emphasis> to reducing sediments: rhizome metabolic gas fluxes and enhanced O<Subscript>2</Subscript> and H<Subscript>2</Subscript>S transport

Cordgrasses of the genus Spartina form dense monospecific stands worldwide, profoundly influencing the ecology of estuaries. One species, Spartina anglica, originated by allopolyploidy in the 1800s and has been particularly prolific as an invasive species worldwide. S. anglica tolerates low-lying estuarine mudflats that its progenitor species and other coastal halophytes cannot. However, very little is known of the physiology of S. anglica. In the present study, an automated flow-through respirometry system was used to quantify metabolic gas fluxes (O₂, H₂S, CO₂, and NH₃) of S. anglica rhizomes. Enhanced physiological mechanisms to transport O₂ and H₂S in both directions between the rhizosphere and the atmosphere were exhibited by S. anglica, but not by the native North American species S. alterniflora. These results suggest that tolerance of anoxia and H₂S may assist S. anglica in colonizing extensively flooded environments. Enhanced sediment oxygenation by S. anglica may be potentially useful for phytoremediation of contaminated sediments, since microbial degradation of organic pollutants is often limited by O₂ availability.     

A systematic study of some Black Corals species (Antipatharia,Hexacorallia) based on rDNA internal transcribed spacers sequences

A phylogenetic analysis based on rDNA internal transcribed spacers (ITS) sequences was performed on 15 species of black corals assigned to the genera Antipathes, Stichopathes, Cirrhipathes, Rhipidipathes, Antipathella, Myriopathes and Cupressopathes recorded from the Messina Strait (Mediterranean Sea) and the Bunaken Marine Park (Celebes Sea, Indonesia). The phylogenetic analysis shows that the examined species are grouped in two main branches corresponding to the families Antipathidae-Aphanipathidae and Myriopathidae. While among the Myriopathidae species there is a very small genetic distance, the Antipathidae-Aphanipathidae clade shows a high degree of divergence between different genera. According to this study, the taxon Antipathes? sp. 3 characterised by a bush-like corallum without a well-defined axis, probably belongs to a new undescribed genus of the family Antipathidae.     

Four genes,morphology and ecology: distinguishing a new species of <Emphasis Type="Italic">Acesta</Emphasis> (Mollusca; Bivalvia) from the Gulf of Mexico

There is currently an active scientific debate about the most correct and efficient way to identify species. To date, few studies in the marine realm have combined the available taxonomic methods. In this study we have used morphology, ecology and molecular analyses to identify a new species within the bivalve genus Acesta. All four genes studied (12S, 16S, Cytb, COI) suggested that a common cold-seep species in the Gulf of Mexico, A. bullisi, should be divided into two distinct species. This conclusion was supported by morphological traits and by observations of ecological distribution. A. oophaga Järnegren, Schander and Young n. sp. is described here, and A. bullisi Vokes (Tulane Stud Geol 2:75–92, 1963) is re-described. This study shows that DNA barcoding in combination with traditional morphological and ecological analyses may be an important tools to identify hidden biodiversity among deep-water organisms such as bivalves.     

Genetic structure of<Emphasis Type="Italic"> Linckia laevigata</Emphasis> and<Emphasis Type="Italic"> Tridacna crocea</Emphasis> populations in the Palawan shelf and shoal reefs

Allozyme variation of 10 populations of Linckia laevigata at 8 polymorphic loci and 13 populations of Tridacna crocea at 6 polymorphic loci were analyzed to compare genetic variability and genetic affinities among reefs in Palawan, Philippines. Two to five populations were sampled from each of four regions: the shelf reefs in (1) northern Palawan and (2) southern Palawan and the offshore reefs in (3) the Kalayaan island group (KIG) in the South China Sea and (4) the Tubbataha shoals in the Sulu Sea. Heterozygosity was highest in populations of L. laevigata from the south shelf of Palawan and populations of T. crocea from the Tubbataha shoals of the Sulu Sea. The lowest heterozygosity estimates were from the reefs of the KIG in the South China Sea, for both species. Overall F _ST values for both species were significant, with an estimated average number of effective migrants per generation (N _EM) of 4.85 (~5 individuals) for L. laevigata and 3.54 (~4 individuals) for T. crocea. Within-region comparisons showed N_EM ranging from 6.29 to 92.34 for L. laevigata and from 3.40 to 6.30 for T. crocea. The higher gene flow among L. laevigata populations relative to T. crocea is consistent with the greater dispersal potential of the former species. Finer scale genetic structuring was evident in T. crocea populations. For both species, the Tubbataha reefs in the Sulu Sea have higher genetic affinity with the populations from the southern shelf of Palawan, while the reefs in the KIG had higher affinity with the northern Palawan shelf reefs. The north and south shelf populations have the least genetic affinity. Genetic patchiness among reefs within regions suggests the importance of small-scale physical factors that affect recruitment success in structuring populations in small island and shoal reef systems in Palawan.     

Free-living marine nematodes from Biscayne Bay,Florida, I. Comesomatidae: the male of Laimella longicauda Cobb, 1920, and description of Actarjania new genus

The male of Laimella longicauda Cobb, 1920 is described as having short arcuate spicules and a gubernaculum with caudally directed apophyses. The genus Paracomesoma Schuurmans Stekhoven, 1950 is reinstated to accommodate species of Laimella sensu Chitwood, 1937. Paramesonchium n. gen. is proposed to accommodate Laimella (?) serialis Wieser, 1954. Actarjania n. gen. (type species A. splendens n. sp.) differs from Sabatieria in having irregular lateral rows of longitudinal punctations and short arcuate spicules with distinctive distal extremities.     

Geographical expansion of the invader <Emphasis Type="Italic">Caprella scaura</Emphasis> (Crustacea: Amphipoda: Caprellidae) to the East Atlantic coast

Caprella scaura (Templeton in Trans Entomol Soc Lond 1:185–198, 1836) is a native species to the western Indian Ocean. It was first described from Mauritius and later reported from several regions of the world. During the last decade, the species spread out of the Adriatic Sea, and in 2005, C. scaura was reported in Gerona, on the north-eastern coast of Spain. The present study shows the recent rapid expansion of the species to the East Atlantic. During a sampling survey of harbours along the Strait of Gibraltar (Dec 2009–June 2010), we found high densities of C. scaura associated with the bryozoans Zoobotryon verticillatum Della Chiaje, 1822, in Chipiona and Bugula neritina (L.) in Cádiz, Atlantic coast of southern Spain; on the other hand, during May 2009, an important population of C. scaura was also found in the Canary Islands (Tenerife) associated with aquaculture resources. A total of 1,034 individuals of C. scaura were studied, and we confirm that the populations are effectively established, with high densities and reproducing females during the whole year. The population from Cádiz was characterised by smaller specimens but a higher number of eggs per female. These differences could be related to environmental conditions, mainly sea water temperature and to other factors such as competition with other species, or availability of food or substrate. Significant correlation was found between female size and number of eggs in the three populations, but egg size did not vary with female body length. The morphometric relation length/width of the second gnathopod was also calculated and compared between sexes: larger males presented longer gnathopods at the three sites. The most probable introduction vector of this species is shipping; in fact, the Strait of Gibraltar is characterised by an intense shipping traffic. Also, we have observed that the native Caprella equilibra Say, 1818, is being displaced by C. scaura in the harbour of Cádiz, where this species reach densities of 35,945 ind/1,000 g of B. neritina. Further experimental studies are necessary to explore the potential danger of this species, which might spread into natural habitats too.     

Feeding strategies and diets of breeding grey-headed and wandering albatrosses at South Georgia

The foraging areas and diets of the grey-headed albatross Thalassarche chrysostoma and wandering albatross Diomedea exulans were studied in March/April 2000 at Bird Island, South Georgia, during their respective chick-rearing and brood-guard periods. Oceanographically, March/April 2000 was abnormal, with warm conditions close to South Georgia. These conditions affected albatross foraging behaviour, particularly that of grey-headed albatrosses. Both species tended to forage in different areas of the ocean, with significant differences in trip durations. Grey-headed albatrosses (n=9) foraged mainly in Antarctic waters (predominantly shelf waters of the South Shetland Islands and Antarctic Peninsula, and also in oceanic waters around South Georgia), feeding mainly on krill (Euphausia superba; 77% by mass). Foraging trips lasted 13.3 days (range: 5–26 days), far longer than the 1–3 days found in previous studies. Only one grey-headed albatross was associated with the APF (Antarctic Polar Front), a reported foraging area in recent studies. Wandering albatrosses (n=9) foraged in Antarctic (South Georgia Shelf) and Antarctic Polar Frontal Zone (APFZ) waters, with trips of 1–4 days trip duration (usual for this species), feeding on fish (46% by mass) and cephalopods (32%). One bird was associated with the APF, and two birds foraged on the shelf/shelf break over the Patagonian shelf. These findings suggest that sea surface temperature anomalies, produced by movement of the APF closer to South Georgia or by eddies, may have had an effect on the foraging strategy of grey-headed albatrosses that year (the main prey of grey-headed albatrosses in previous studies, the ommastrephid Martialia hyadesi, is known to be associated with the APF). Also, when both albatross breeding periods overlap, their foraging areas were complementary, which reflected the prey taken.     

Evaluation of microelement contents in <Emphasis Type="Italic">Clethra barbinervis</Emphasis> as food for human and animals in contrasting geological areas

The young leaves of Clethra barbinervis Sieb. et Zucc, which is a deciduous tree species found in secondary forests widely in Japan, are used in spring as a local traditional food by local populations, and the bark of this plant is also preferred by sika deer, Cervus nippon. However, C. barbinervis has been known to accumulate heavy metals in its leaves. Then, we aimed to clarify the characteristics of microelement contents in C. barbinervis and to discuss the value of this species as food for humans and animals through the analysis of seasonal changes and distribution in various organs of C. barbinervis growing under two different geological conditions. We found that C. barbinervis is an accumulating and tolerant plant for Ni, Co and Mn. It accumulates Ni from serpentine soil containing Ni at high concentration, and Co and Mn from acidic soils based on crystalline schist. The seasonal variation in element concentrations in leaves indicates that the young leaves contain Cu at high concentration and that eating them in spring season may be advantageous to humans, due to the associated increase in Cu intake. The high concentrations of Cu and Zn in the bark of C. barbinervis might explain why deer prefer to eat the bark of this species.     

Impact of pedological conditions on the distribution of Salicornia species (Southern North Sea coast)

The zonation of different Salicornia species within saltmarshes has been described controversially in prior publications. The aim of this study is to detect substantial relations between pedological conditions and the distribution of different Salicornia species (Salicornia stricta Dumort. 1868, Salicornia europaea L. 1753, and Salicornia procumbens Sm 1813). 37 sites were investigated regarding vegetation pattern, soil morphology and physicochemical and chemical soil properties. A multivariate approach indicate a clear differentiation of the sites dominated by different Salicornia species in respect to sand content, redox potential and water content. However, results of a detailed statistical assessment indicate that redox potential and salinity are the most relevant parameters. Salicornia stricta sites are characterized by a variety of grain sizes, reduced conditions in the rhizosphere, highest water contents (median: 71.5 Vol-%) and lowest Eh values (median: ?19.0 mV), indicating the best adaptation to anaerobic soil conditions. Salicornia procumbens occurs on aerated soils (median Eh: 455.6 mV) with high sand contents independent to position relative to mean high tide level. Exhibiting the lowest (11.5‰) and highest soil salinities (41.7‰), even developing in salt pans (136‰), Salicornia europaea feature a great ecological amplitude regarding temporal variations of salinity. These findings underline the ecotypic and phenotypic plasticity of Salicornia species and offer a promising approach for further experimental settings focussing on phenotypic adaptions and ecological amplitudes of Salicornia taxa and ecotypes.     

Free-living marine nematodes from Biscayne Bay,Florida, II. Oncholaimidae: descriptions of five new species and one new genus (Meyersia)

A new genus, Meyersia, and five new species of the nematode family Oncholaimidae, are described from Biscayne Bay, Florida, and environs, viz., Metoncholaimus pelor n. sp., M. amplus n. sp., Meyersia major n. gen., n. sp., M. minor n. sp., and Filoncholaimus prolatus n. sp. Also included in the genus Meyersia are Adoncholaimus bandaenis Kreis, 1932 and A. meridionalis Kreis, 1932.     

Ecology of a corallivorous gastropod,<Emphasis Type="Italic"> Coralliophila abbreviata</Emphasis>, on two scleractinian hosts. I: Population structure of snails and corals

Despite their potential importance in structuring reef communities, invertebrate corallivores and their population structures are poorly understood. We found distinct differences in the population structures (length-frequency distribution and sex ratio) of the corallivorous gastropod Coralliophila abbreviata residing on two coral-host taxa, Montastraea spp. and Acropora palmata, in the Florida Keys. In each of two survey years, around 50% of the Montastraea spp. colonies were infested, with a mean snail density of eight snails per infested colony (range 1–45), while around 20% of A. palmata colonies harbored three snails per infested colony (range 1–23). Variation in patterns of snail occurrence was also observed within a host taxon. A. palmata occurred in low- and high-density stands (0.4 and 1 colony m^–2, respectively, at the initial survey) at different sites. Hurricane Georges struck the area in September 1998. When resurveyed in 1999, density of colonies in low-density stands had decreased by 75% to 0.1 colonies m^–2. This decrease was accompanied by a doubling in the proportion of colonies infested with snails (from 19% to 46%) and an increase in snail density per infested colony (from 3.7±3.3 SD to 5.4±4.6 SD) as snails apparently concentrated on surviving A. palmata. In contrast, sites with high density A. palmata stands (thickets) retained colony densities of about ~1 colony m^–2 among years, while snail infestation increased only from 9% to 14% of colonies surveyed and snail density essentially remained unchanged (from 2.7±1.8 to 2.9±1.9 snails per infested colony). Snails collected from Montastraea spp. were shorter than those from A. palmata in low-density stands and were longest on A. palmata in thickets. On both host taxa, female snails were longer than males. The sex ratio of snails on Montastraea spp. hosts was even (1:1), while that of snails on A. palmata was skewed (70% males). Factors that could explain observed differences in size structure and sex ratio between Coralliophila populations on the two coral host taxa include: differential susceptibility to predators, influence of host tissue nutritional quality and/or secondary metabolite content, and genetic differences (cryptic species). The host-specific characteristics of C. abbreviata populations imply that the impact of gastropods on reef communities will vary with the coral species composition.