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Larvae in the coastal ocean are transported toward shore by a variety of mechanisms. Crossing the surf zone is the last step in a shoreward migration and surf zones may act as semipermeable barriers altering delivery of larvae to the shore. We related variation in the structure of intertidal barnacle populations to surf zone width (surf zone hydrodynamics proxy), wave height, alongshore wind stress (upwelling proxy), solar radiation, and latitude at 40 rocky intertidal sites from San Diego, California to the Olympic Peninsula, Washington. We measured daily settlement and weekly recruitment of barnacles at selected sites and related these measures to surf zone width. Chthamalus density varied inversely with that of Balanus, and the density of Balanus and new recruits was negatively related to solar radiation. Across the region, long-term mean wave height and an indicator of upwelling intensity and frequency did not explain variation in Balanus or new recruit densities. Balanus and new recruit densities, daily settlement, and weekly recruitment were up to three orders of magnitude higher at sites with wide (>50 m), more dissipative surf zones with bathymetric rip currents than at sites with narrow (

Metal concentrations were measured in predominant coastal fauna of the Caspian Sea including six macro-invertebrates (Mnemiposis leidyi, Balanus improvisus, Pontogammarus maeoticus, Palaemon adspersus, Cerastoderma glucaum and Adacna vitrea) and three species of small fish (Atherina caspia, Neogobius caspius and N. pallasi) to determine potential bio-indicators (for the first time to our knowledge). It is to be noted that metal concentrations have also never been reported in M. leidyi and A. vitrea. The lowest levels of metal were observed in muscles of fishes. Most of metals were detectable in the macro-plankton M. leidyi suggesting that this species could be used for water pollution monitoring, worldwide. Our results suggest the use of C. glucaum and A. vitrea as indicators of Ni and Cd contamination, respectively. B. improvisus has a high potential as an indicator for Zn and Cu pollution, while P. adspersus and P. maeoticus showed this capacity for Cu. This study provides a baseline for biomonitoring programs elsewhere in the Caspian Sea. Furthermore, the species C. glucaum and B. improvisus could be used for comparisons of metal contamination worldwide. [ABSTRACT FROM AUTHOR]

Se describen las primeras fases de nauplios de especies chilenas; Balanus (Megabalanus) psittacus (Molina, 1782), Balanus (Austrobalanus) flosculus Darwin, 1854, y Elmintus kingi Gray, 1831 (Cirripedia, Balanidae). Sobre la base de una prueba de laboratorio, iniciada con especímenes adultos recolectados en Estero Chope (11°48?S; 73°05?O), y en el estuario del río Contaco (40°34?S; 73°37?O), la estructura general del cuerpo, las apófisis caudal y abdominal, el cono bucal y los apéndices, la setación se describen comparativamente en términos de número, disposición y tipo de setas, de manera de obtener los caracteres diferenciadores intra e interespecíficos. También se establecen características morfológicas que aseguran una rápida identificación de todas las fases a nivel de grupo. Se incluye una descripción del cypris de Balanus psittacus, detallando la estructura del cirro, las antenas adhesivas, etc.

Pelagic larvae of benthic organisms comprise a substantial part of the coastal Arctic zooplankton community in spring–summer. We studied the timing, growth, and pelagic duration of Cirripedia larvae in Adventfjorden, a high-Arctic fjord in Spitsbergen, Svalbard. Two distinct abundance peaks were found: one in early May (~ 25.000 ind. m−3) and another one in late May (~ 35,580 ind m−3). DNA barcoding based on the COI gene was used to identify the barnacle larvae to species. Whereas both Balanus balanus and Semibalanus balanoides were present, the first one dominated (50–100%) the barnacle abundance. High resolution sampling and size measurements of Cirripedia larvae revealed that these larvae most likely originated from a single spawning event. Development of the larvae suggested a pelagic residence time of roughly 2 months for B. balanus and at least 1 month for S. balanoides in the Arctic. Long pelagic residence time, large potential for biofouling on ships and larger plastic debris, combined with the disappearance of landfast sea ice and less ice scouring opens up new opportunities for barnacles to colonize the high-Arctic littoral zone. In a future warmer Arctic, we therefore expect establishment of new, more temperate Cirripedia species in Svalbard. [ABSTRACT FROM AUTHOR]

The importance of mariculture areas for the dispersal of alien invasive species (AIS) on artificial floating items has recently been highlighted as a priority research need. Here we present the results of surveys in two important European shellfish culture areas that release rafting AIS, the Venetian lagoon and the Portuguese Algarve region. We found eight aquaculture-related non-native, invasive species attached to anthropogenic litter items mostly related to aquaculture: Amphibalanus amphitrite , Austrominius modestus , Balanus trigonus , Hesperibalanus fallax , Hydroides elegans , Hydroides sanctaecrucis , and Magallana angulata . These species are well-adapted to rafting on artificial surfaces and have a high potential to disperse via this vector. This is the first record of the notorious nuisance species H. sanctaecrucis both in the Mediterranean and Eastern Atlantic, as well as on floating litter. We also present the first records of M. angulata , H. sanctaecrucis , Sabellaria alveolata , Mytilus edulis and Chthamalus montagui on stranded anthropogenic litter. [ABSTRACT FROM AUTHOR]

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How the calcareous bases of acorn barnacles are interfacially structured and conserved for underwater attachment function remains unclear, especially given the existence of proteinaceous adhesives in between the bases and substrata. We demonstrate with the barnacle Balanus albicostatus that the base adopts a unique, disc saw-like geometry, densely perforated with radial microchannels that are intelligently built by the animal to enhance adhesion. Meanwhile, the base is shown to be constructed of intergrown calcitic microcrystals with almost no preferred orientation, some varied extent of morphologic change and high level of atomic disorder compared to its geological equivalent. Further, both protein and polysaccharide chemistries are found to be involved in the microstructural development of the base by virtue of their acidic functional groups or confined space, with the latter (behaving as a hydrogel) possibly being dominant in amount. The key microstructural features along with the placement of organic components play crucial roles in the mechanical response of the base to external loads. Our results explain how the barnacle base has been evolutionarily adjusted over different length scales to enhance adhesion, which would lay the foundation of research into antifouling strategy as well as the synthesis of organic-inorganic hybrid interfacial materials. [ABSTRACT FROM AUTHOR]

As invasions become increasingly prevalent, it is important to understand how spread may be moderated by environmental conditions. This study considered the effect of location and changing substratum temperature on the early life-history processes of the alien barnacleBalanus glandulaand its native comparator,Chthamalus dentatus, along the South African coast. Using settlement plates of different colours, temperature was manipulated to assess settlement, mortality, recruitment and growth of the two species. These variables were tracked over 10 weeks using repeat photography. Unexpectedly, there was no evidence of an effect of temperature on early life-history processes of either species. Settlement by the two barnacles was spatially segregated, withB. glandulaoccurring only on the West Coast where it is the dominant intertidal barnacle, whileC. dentatussettled only on the South Coast, which has only recently been invaded by the alien. Despite this, it was notable that the relative settlement ofB. glandulaon rock was higher than that ofC. dentatus. However, the lack of mortality of the native resulted in comparable levels of recruitment among the species. Nonetheless, the propensity ofB. glandulato settle sporadically, coupled with fast growth, suggests that the invader may still possess the ability to become dominant along the newly invaded South Coast. This study highlights that measurements of early life-history parameters may not adequately predict the future range and impacts of alien species unless interpreted within the broader context of the nature of the recipient region and species-specific traits of the invader. [ABSTRACT FROM AUTHOR]

Marine mollusks provide shelter to epibiotic organisms which settle on the outer surface of their hard shells. Epibionts can exert beneficial or detrimental effects on the host mollusk. In this study, the ecology of the association of the commercially valuable marine mobile scallop Patinopecten ( =Mizuhopecten) yessoensis with its epibiotic barnacle Balanus rostratus was investigated. Fatty acid analysis was performed to determine the trophic relationships between these species. The distribution of fatty acid markers in this scallop species suggests an important contribution of diatoms, flagellates and animal material in its diet. The fatty acid analysis indicated a predominance of diatoms in the diet of the adult barnacles and some detrital input into the diets of young individuals. It was found that adult barnacles may compete with the scallops for food sources such as diatoms and zooplankton. It was revealed that with a negligible biomass of epibionts, the interactions between the barnacle and scallop may be regarded as commensalisms. An increase in the weight of epibiotic barnacles resulted in decreases in the weights and shell heights of the scallops, testifying to the adverse influence of a high biomass of epibionts on their host. [ABSTRACT FROM AUTHOR]

The barnacle is well known for its tenacious and permanent attachment to a wide variety of underwater substrates, which is accomplished by synthesizing, secreting and curing a mixture of adhesive proteins termed “barnacle cement”. In order to evaluate interfacial adhesion abilities of barnacle cement proteins, the cp19k homologous gene in Balanus albicostatus (Balcp19k) was cloned and expressed in Escherichia coli. Here, we report an intriguing discovery of a gel-like super adhesive aggregation produced by Trx-Balcp19k, a recombinant Balcp19k fusion protein. The Trx-Balcp19k consists of an 18 kDa fragment at the N-terminus, which is encoded by pET-32a(+) plasmid and mainly comprised of a thioredoxin (Trx) tag, and Balcp19k at the C-terminus. The sticky aggregation was designated as “Trx-Balcp19k gel”, and the bulk adhesion strength, biochemical composition, as well as formation conditions were all carefully investigated. The Trx-Balcp19k gel exhibited strong adhesion strength of 2.10 ± 0.67 MPa, which was approximately fifty folds higher than that of the disaggregated Trx-Balcp19k (40 ± 8 kPa) and rivaled those of commercial polyvinyl acetate (PVA) craft glue (Mont Marte, Australia) and UHU glue (UHU GmbH & Co. KG, Germany). Lipids were absent from the Trx-Balcp19k gel and only a trace amount of carbohydrates was detected. We postulate that the electrostatic interactions play a key role in the formation of Trx-Balcp19k gel, by mediating self-aggregation of Trx-Balcp19k based on its asymmetric distribution pattern of charged amino acids. Taken together, we believe that our discovery not only presents a promising biological adhesive with potential applications in both biomedical and technical fields, but also provides valuable paradigms for molecular design of bio-inspired peptide- or protein-based materials. [ABSTRACT FROM AUTHOR]

The strength of top-down control by consumers is predicted to decrease with latitude, but most data confirming this assumption come from latitudes <60°, while empirical studies of predation in sub-arctic and arctic marine habitats are few. A barnacle Balanus crenatus is a native foundation species in the shallow subtidal of the White Sea (65° N), hosting a diverse (250+ species) assemblage of macrobenthic organisms. On mixed sediments live barnacles share primary substrates (shells and gravel) with numerous empty barnacle tests, 7% of which had drill holes of an unidentified origin. We manipulated the densities of (i) adult muricid whelks Boreotrophon clathratus (of previously unknown feeding habits), to check if they prey on barnacles, (ii) other predators to reveal their effect on juvenile Boreotrophon, and (iii) empty tests to assess the community-wide effect of predation on barnacles. The abundance of drilled empty tests in the field correlated with that of Boreotrophon. A year-long caging experiment clearly confirmed predation, showing the highest barnacle mortality and proportion of drilled tests in whelk enclosures, and the lowest — in predator exclosure treatments. Boreotrophon preferred the barnacles attached to conspecifics to those from primary substrates. Because of its scarcity Boreotrophon had a minor direct effect on barnacle abundance in the field. Yet, initially defaunated empty tests and live barnacles developed markedly different macrobenthic assemblages, suggesting a strong indirect effect of the predation. Juvenile Boreotrophon were 5-6 times less abundant in open and partial cages than in exclosures and enclosures, which indicates that the recruitment and, consequently, the abundance of Boreotrophon and its predation on Balanus are top-down controlled by apex predators. In contrast, in tropical and temperate intertidal the predation on barnacles is stronger and primarily limited by environmental stress and prey availability. [ABSTRACT FROM AUTHOR]

The highly specialized coronulid barnacle Xenobalanus globicipitis attaches exclusively on cetaceans worldwide, but little is known about the factors that drive the microhabitat patterns on its hosts. We investigate this issue based on data on occurrence, abundance, distribution, orientation, and size of X. globicipitis collected from 242 striped dolphins (Stenella coeruleoalba) that were stranded along the Mediterranean coast of Spain. Barnacles exclusively infested the fins, particularly along the trailing edge. Occurrence, abundance, and density of X. globicipitis were significantly higher, and barnacles were significantly larger, on the caudal fin than on the flippers and dorsal fin. Barnacles were found more frequently and in greater numbers on the dorsal rather than ventral side of the caudal fin and on the central third of dorsal and ventral fluke surfaces. Nearly all examined individuals attached with their cirral fan oriented opposite to the fluke edge. We suggest that X. globicipitis may chemically recognize dolphins as a substratum, but fins, particularly the flukes, are passively selected because of creation of vortices that increase contact of cyprids with skin and early survival of these larvae at the corresponding sites. Cyprids could actively select the trailing edge and orient with the cirri facing the main direction of flow. Attachment on the dorsal side of the flukes is likely associated with asymmetrical oscillation of the caudal fin, and the main presence on the central segment of the flukes could be related to suitable water flow conditions generated by fluke performance for both settlement and nutrient filtration. [ABSTRACT FROM AUTHOR]

Biochemical biomarkers were evaluated in the barnacle Balanus improvisus (Crustacea: Cirripedia) sampled from both polluted and reference sites in the Patos Lagoon Estuary, Southern Brazil. During winter, higher glutathione S -transferase (GST) activity was recorded in the barnacles from the polluted sites, indicating environmental exposure to contaminants. Relatively low lipid peroxide levels (LPO) were also observed in barnacles from polluted sites, indicating that oxidative stress by lipid peroxidation was not a major threat in barnacles from those sites. Seasonal differences in the GST and total oxyradical scavenging capacity (TOSC) could have contributed to the low LPO levels in the summer relative to the levels in the winter. Catalase activity and metallothionein levels were not affected by contamination or seasonality. The seasonal changes observed in biomarker responses were paralleled by the differences in temperature, which could have affected physiological responses, including the balance between pro-oxidants and antioxidants. [ABSTRACT FROM AUTHOR]

Energy availability and local adaptation are major components in mediating the effects of ocean acidification ( OA) on marine species. In a long-term study, we investigated the effects of food availability and elevated pCO2 (ca. 400, 1000 and 3000 μatm) on growth of newly settled Amphibalanus (Balanus) improvisus to reproduction, and on their offspring. We also compared two different populations, which were presumed to differ in their sensitivity to pCO2 due to differing habitat conditions: Kiel Fjord, Germany (Western Baltic Sea) with naturally strong pCO2 fluctuations, and the Tjärnö Archipelago, Sweden (Skagerrak) with far lower fluctuations. Over 20 weeks, survival, growth, reproduction and shell strength of Kiel barnacles were all unaffected by elevated pCO2, regardless of food availability. Moulting frequency and shell corrosion increased with increasing pCO2 in adults. Larval development and juvenile growth of the F1 generation were tolerant to increased pCO2, irrespective of parental treatment. In contrast, elevated pCO2 had a strong negative impact on survival of Tjärnö barnacles. Specimens from this population were able to withstand moderate levels of elevated pCO2 over 5 weeks when food was plentiful but showed reduced growth under food limitation. Severe levels of elevated pCO2 negatively impacted growth of Tjärnö barnacles in both food treatments. We demonstrate a conspicuously higher tolerance to elevated pCO2 in Kiel barnacles than in Tjärnö barnacles. This tolerance was carried over from adults to their offspring. Our findings indicate that populations from fluctuating pCO2 environments are more tolerant to elevated pCO2 than populations from more stable pCO2 habitats. We furthermore provide evidence that energy availability can mediate the ability of barnacles to withstand moderate CO2 stress. Considering the high tolerance of Kiel specimens and the possibility to adapt over many generations, near future OA alone does not seem to present a major threat for A. improvisus. [ABSTRACT FROM AUTHOR]

Highlights: [•] Our results provide the first numerical estimate age of strata underlying invertebrate fauna, Sahabi, Libya. [•] 87Sr/86Sr and calcareous nannofossil both indicate a Late Miocene age for Formation M. [•] Our results help revising the complex stratigraphy of Sahabi and surrounding regions. [Copyright &y& Elsevier]

Zooplankton provide microhabitats for bacteria, but factors which influence zooplankton-associated bacterial abundance are not well known. Through a year-long field study, we measured the concentration of free-living bacteria and bacteria associated with the dominant mesozooplankters Acartia tonsa and Balanus sp. Free-living bacteria peaked in the summer, while zooplankton-associated bacteria peaked in summer and winter. No relationships were found between bacterial abundance per individual and zooplankter width, length, surface area or body volume. Multiple regression analyses indicated that free-living and Acartia-associated bacterial concentrations were explained by temperature, salinity, ammonium, chl a, and all term interactions. Balanus-associated bacterial concentration was explained by ammonium and phosphate. Ammonium significantly influenced all sampled bacterial communities. In laboratory experiments, copepods raised under high ammonium concentration had higher bacterial concentrations than those raised under low ammonium condition. Transplant experiments showed that high ammonium favored loosely attached bacteria, whereas low ammonium selected for firmly attached bacteria, suggesting greater exchange between free-living and zooplankton-associated bacterial communities in nutrient-rich systems. Additional sampling of other zooplankton taxa all showed high bacterial concentrations, supporting the notion that zooplankton function as microbial hotspots and may play an important, yet overlooked, role in marine biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Barnacles are often considered invasive species because they spread to non-native waters via shipping and the movement of floating objects. In this study, we surveyed barnacles attached to decrepit, unloaded fish aggregating devices. These objects act like stepping stones for sessile organisms in the ocean. Barnacles were sampled and identified to the lowest taxonomic level possible. Eight barnacle species were recorded, three of which are new records for Japanese waters ( Newmanella radiata, Tesseropora sp., Balanus sp.). [ABSTRACT FROM AUTHOR]

It was showed using the example of carbon and high alloyed steels that microfouling that develops on the surface of metals possesses high corrosion activity and stimulates corrosion processes. Local corrosion of high alloyed steels can be activated by the vital activity of anaerobic microorganisms under bases of balanus barnacle lodges. Corrosion on metals almost does not develop in the absence of microorganisms (sterile conditions). Microfouling is involved in the destruction of organic basis of protective antifouling coatings, and this process is considered positive. [ABSTRACT FROM AUTHOR]

Were studied external structure of parasite Octolasmis sp and Balanus sp affecting crab blue swimmer water Gulf - Eastern Province of Saudi Arabia using the scanning electron microscope (SEM) and recorded the study was to study the regions of the peduncle and cervical in the parasite Octolasmis sp shown to covering surface of the body with hold arranged in the form of tapes and the cervicalis characterized as a pleated cover the same nipples and different from the rest of the body and that the capitulum and the cirriform appendages cover the thorns of different lengths, while the rest of the body covered by granules and the study showed also that the parasite Barnacles Sea Balanus sp there is in the form of personnel adjacent to the body host of different sizes in the areas of paper and legs chelicera in both males and females. And the body of the parasite is installed on the body of crab by the baseband (the area of strabismus Femip crab), which contains six appendices cirris, as well as the body of Balanus sp have calcareous structure . This is the first study in this area. [ABSTRACT FROM AUTHOR]

One new dimeric diterpenoid, 8(14)-enyl-pimar-2'(3')-en-4'(18')-en-15'(16')-endolabr- 16,15,2',3'-oxoan-16-one (1) and five known terpenoids: Tagalsin C (2), Tagalsin I (3), lup-20(29)-ene-3&bgr;,28-diol (4), 3-oxolup-20(29)-en-28-oic acid (5) and 28-hydroxylup- 20(29)-en-3-one (6) were isolated from the roots of the mangrove plant Ceriops tagal. Their structures and relative stereochemistry were elucidated by means of extensive NMR, IR and MS analysis. The antifouling activity against larval settlement of the barnacle Balanus albicostatus were evaluated using capsaicin as a positive control. All these terpenoids exhibited antifouling activity against cyprid larvae of the barnacle without significant toxicity. The structure-activity relationship results demonstrated that the order of antifouling activity was diterpenoid (Compound 2) > triterpenoid (Compounds 4, 5 and 6) > dimeric diterpenoid (Compounds 1 and 3). The functional groups on the C-28 position of lupane triterpenoid significantly affect the antifouling activity. The diterpenoid dimmer with two identical diterpenoid subunits might display more potent antifouling activity than one with two different diterpenoid subunits. The stability test showed that Compounds 2, 4, 5 and 6 remained stable over 2-month exposure under filtered seawater. [ABSTRACT FROM AUTHOR]

Abstract: The ontogenetic cycle of the barnacle Balanus amphitrite (=Amphibalanus amphitrite) (Darwin, 1854) includes a cyprid that binds submerged surfaces, metamorphosing into a sessile adult. γ-Aminobutyric acid (GABA) and GABA receptors have recently been located in its cyprid with a similar pattern to other crustaceans. Since NMDA R1 ionotropic glutamatergic receptors have been identified in crustacean neuromuscular junctions, we have investigated their presence in the B. amphitrite cyprid. The presence of NMDA R1 receptors might indicate a role for glutamate in neuromuscular control in B. amphitrite cyprids, therefore we studied the presence and distribution of the NMDA R1 by immunohistochemistry. Its distribution was observed in the peripheral nervous system and in non-neuronal elements. Actually, NMDA R1 immunoreactivity was detected in thoracic appendages, at the level of neuromuscular junctions, thus suggesting an involvement in motor control functions, as already demonstrated in other crustaceans. Immunoreactivity was also detected in ommatidia cells of the eye, in antennules, and in epidermal cells. The distribution pattern comparable to that of GABAergic molecules could indicate an interrelated agonistic/antagonistic role for these two systems, which could be considered as potential targets of combined antifouling strategies. [ABSTRACT FROM AUTHOR]

Abstract: Cyprid larvae of barnacles are developmentally competent to carefully explore hard surfaces and to discriminate among various environmental cues, thus making them capable identifying suitable habitats (substrates) for attachment and metamorphosis. Cyprids, depending on the species, use a variety of substrate-associated chemical cues to select a suitable microhabitat for attachment, a process usually referred to as “cypris substrate selection”. At a small spatial scale, cypris substrate selection plays a key role in determining adult distribution and abundance. Therefore, exogenous and endogenous regulatory mechanisms of cypris selection have been the subject of interdisciplinary ecology research for the past two decades and recently, it has also been examined in the context of antifouling. This article reviews literature on cypris substrate selection and the chemical cues (especially biofilms) associated with this process, and discusses recent interdisciplinary research approaches that integrate cypris substrate choice with their complex physico-biochemical response to chemical cues. This article also gives an overview of recent advances in larval proteomics, i.e. the large-scale study of proteins expressed by a whole larva. Finally, it suggests that future research should 1) address long-term impacts of cypris substrate selection on adult distribution, 2) investigate whether cyprids are able to remember unsuitable substrates that they have encountered and use that information in their search for preferred substrate, 3) focus on cypris selection behavior under realistic field conditions, and 4) apply modern molecular technologies such as transcriptomics and proteomics, to trace molecular pathways that trigger cypris attachment on suitable substrate and that underlie cypris substrate selection. [ABSTRACT FROM AUTHOR]

Zwitterionic polymers such as poly(sulfobetaine methacrylate) (polySBMA) and poly(carboxybetaine methacrylate) (polyCBMA) have demonstrated impressive fouling-resistance against proteins and mammalian cells. In this paper, the effects of these surface chemistries on the settlement and behavior of an ubiquitous fouling organism, the cypris larva of the barnacle Balanus amphitrite (=Amphibalanus amphitrite), were studied in the laboratory. Conventional settlement assays and behavioral analysis of cyprids using Noldus Ethovision 3.1 demonstrated significant differences in settlement and behavior on different surfaces. Cyprids did not settle on the polySBMA or polyCBMA surfaces over the course of the assay, whereas settlement on glass occurred within expected limits. Individual components of cyprid behavior were shown to differ significantly between glass, polySBMA and polyCBMA. Cyprids also responded differently to the two zwitterionic surfaces. On polySBMA, cyprids were unwilling or unable to settle, whereas on polyCBMA cyprids did not attempt exploration and left the surface quickly. In neither case was toxicity observed. It is concluded that a zwitterionic approach to fouling-resistant surface development has considerable potential in marine applications. [ABSTRACT FROM PUBLISHER]

The article discusses research done on the impact of solar radiation and ultraviolet radiation (UVR) on the regulation of small-scale settlement patterns and early post-settlement mortality in the barnacle Balanus (B.) glandula. Results indicated that UVR did not affect the ability of B. glandula cyprids to select their settlements. Mortality from attachment to metamorphosis ranged between 60 and 100 percent while cyprids that metamorphosed died after several days. The relationship between solar radiation and survival may be attributed to the impact of solar radiation on heat stress and desiccation.

Abstract: Patterns of vertical distribution in marine invertebrate larvae interact with coastal hydrodynamics to determine cross-shore distributions, dispersal ranges, and scales of connectivity among populations. We present observations on the vertical distribution of barnacle larvae from southern California, collected from 3 depth intervals every 2h and over a 48-h period at a fixed nearshore station. Larvae were identified to species and stage of development, and their vertical distributions were tested for day/night and between-stage differences within each species, as well as for correlations with environmental variability. Stage-specific patterns of vertical distribution were distinct and consistent across species. Nauplii were most abundant near the surface at all times, and were numerically dominated by Chthamalus spp. (78% of Nn =1835). Cyprids were substantially less abundant than nauplii in our samples (Nc =146) and corresponded mostly to the subtidal barnacle Balanus nubilus (84%). Despite the lower counts and different species composition, our data suggest that cyprids remain within the mid-depth and bottom layers, and that changes in their mean depth of distribution (MDD) may track changes in pycnocline depth. Temporal changes in nauplii MDD were not correlated with water-column variability, wind forcing, or tidal height. The apparent vertical segregation of nauplii and cyprids may be related to previously documented differences in the cross-shore distribution of these stages. [Copyright &y& Elsevier]

Abstract: The barnacle Balanus glandula was introduced in Argentina in the 1970s, and today it dominates the high intertidal level in most Argentinean rocky shores. The aim of this work was to evaluate the effect of the type of substrata and intertidal height on a population of Balanus glandula by conducting field surveys and one-year field experiments in which we combined different substrata (hardness: hard and soft, and texture: smooth and rough) at two intertidal heights (mid and high). In natural populations, the highest density of adults and recruits occurred on soft–rough substratum and in the high intertidal. The different textures were important only on the soft substrata and high intertidal, and the density of barnacles of the soft–rough substrata was higher than soft and smooth ones. The most suitable experimental substratum was the soft–rough of the high intertidal, which had the highest recruitment, survival and final density of barnacles at the end of the experiment. In contrast, the hard and smooth of the high and middle intertidal were the least suitable in all cases. Although the recruitment of B. glandula occurred throughout the year, it was higher in the high intertidal, and it showed a recruitment peak in the winter and a second in the summer. While most studies on this barnacle investigated the effects of granite or other volcanic hard substrata, our study also focused on soft substrata. The effects of soft substrata are particularly important because soft sedimentary rocks characterise the southern Atlantic coast of South America and the presence of soft rocks appears to optimize the success of Balanus glandula. [Copyright &y& Elsevier]

Approximately 20 000 years ago the last glacial maximum (LGM) radically altered the distributions of many Northern Hemisphere terrestrial organisms. Fewer studies describing the biogeographic responses of marine species to the LGM have been conducted, but existing genetic data from coastal marine species indicate that fewer taxa show clear signatures of post-LGM recolonization. We have assembled a mitochondrial DNA (mtDNA) data set for 14 co-distributed northeastern Pacific rocky-shore species from four phyla by combining new sequences from ten species with previously published sequences from eight species. Nuclear sequences from four species were retrieved from GenBank, plus we gathered new elongation factor 1-α sequences from the barnacle Balanus glandula. Results from demographic analyses of mtDNA for five (36%) species ( Evasterias troschelii, Pisaster ochraceus, Littorina sitkana, L. scutulata, Xiphister mucosus) were consistent with large population expansions occurring near the LGM, a pattern expected if these species recently recolonized the region. However, seven (50%) species ( Mytilus trossulus, M. californianus, B. glandula, S. cariosus, Patiria miniata, Katharina tunicata, X. atropurpureus) exhibited histories consistent with long-term stability in effective population size, a pattern indicative of regional persistence during the LGM. Two species of Nucella with significant mtDNA genetic structure showed spatially variable demographic histories. Multilocus analyses for five species were largely consistent with mtDNA: the majority of multilocus interpopulation divergence times significantly exceeded the LGM. Our results indicate that the LGM did not extirpate the majority of species in the northeastern Pacific; instead, regional persistence during the LGM appears a common biogeographic history for rocky-shore organisms in this region. [ABSTRACT FROM AUTHOR]

Abstract: Adult acorn barnacles are sessile suspension feeders. This study compares the feeding of three size classes of the barnacle Balanus glandula. Cirral morphology, feeding behavior at a low current speed, and leakiness of the cirri were compared between these size classes: newly-settled juveniles (small, aperture diameter 0.36mm), an intermediate size (medium, aperture diameter 3.4mm), and the largest individuals found locally (large, aperture diameter 6.5mm). Barnacles were videotaped while feeding in a flow tank at a current speed of 4cm/s. Molts were collected and several morphometric and meristic traits were measured. Large individuals spent more time actively feeding and had fewer setae per millimeter of cirrus VI than did medium or small individuals. Small individuals were observed passively feeding, which was not observed in the larger groups. Barnacles tend to passively feed in high current speeds. Juveniles are more likely to experience slower flow speeds in the field due to their tendencies to settle in locally sheltered areas such as in pits and on the sides of adults in clumps. Thus, 4cm/s flow may be near the upper limit of flow speeds encountered by juveniles. Barnacles were videotaped actively feeding while a stream of milk was aimed at their cirri. Two geometric models of leakiness were generated from the observed billows. The small barnacles had cirral fans that were much less leaky than the medium and large barnacles. These calculations and measurements were made at a relatively slow flow speed. Leakiness and Reynolds number (Re) experienced will increase in the field with increasing flow up to some maximum current speed at which the barnacles cease to feed. [Copyright &y& Elsevier]

The barnacle Balanus glandula is predominantly an open coast species in the Northeast Pacific. However, B. glandula densely inhabits estuaries where environmental conditions such as salinity and temperature drastically differ from the open coast. The increased variability of environmental conditions within an estuary can potentially affect spatial patterns of reproduction in B. glandula. I examined gonad maturity, reproductive periodicity and fecundity, and then calculated reproductive output in B. glandula populations distributed along an estuarine gradient. Results indicated that reproductive output of this intertidal barnacle decreased four times over a spatial scale of kilometers, as a transition occurred from a marine to a freshwater habitat along an estuarine gradient. Additionally, a higher proportion of the population had well-developed gonads in the oceanic end of the estuary compared to the riverine end. These results indicate how reproductive pattern can significantly vary over a spatial scale of kilometers, resulting in site-specific contributions of offspring to the larval pool. [ABSTRACT FROM AUTHOR]

A series comprising hexane, ethyl acetate, ethanol and aqueous extracts from six common Chinese herbs (Carpesium abrotanoides, Melia toosendan, Cnidium monnieri, Vitex negundo, Stemona sp. and Sophora flavescens) was investigated for antifouling (AF) activity against cypris (cyprids) larvae of the barnacle Balanus albicostatus. All extracts tested except the aqueous extract from Stemona sp. significantly inhibited the settlement of cyprids, the most potent being the ethyl acetate extract of S. flavescens (EC50 value 2.08 μg ml−1), from which an AF compound, identified as 2′-methoxykurarinone, was isolated using bioassay-guided procedures. Furthermore, the AF activity of this compound was found to be highly reversible and greater than that of the three other natural products from S. flavescens, namely matrine, oxymatrine and oxysophocarpine. These compounds have been used commercially in China for their pharmaceutical activities, but their AF activities have not previously been evaluated. Analysis of structure–activity relationships suggested that the N-1 nitrogen atom in matrine plays a crucial role in AF activity. Overall, the present findings indicate that herbal plants are a valuable source of novel AF agents. [ABSTRACT FROM PUBLISHER]

A new briarane diterpene, juncin ZII ( 1), along with three known briaranes ( 2–4), was isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian Junceella juncea. The structure of 1 was established by extensive spectroscopic analysis, including 1D and 2D NMR data. For compounds 1–4 and eight other briaranes ( 5–12) isolated from J. juncea previously, the antifeedant activity against second-instar larvae of Spodoptera litura and cytotoxicity against S. litura cells were investigated, and it was observed that they all exhibit medium antifeedant activity. Compounds 1, 8, 9, and 12 also showed potent antifouling activity against the larval settlement of barnacle Balanus amphitrite at nontoxic concentrations with EC50 values of 0.004, 0.005, 2.82, and 0.447 μg/mL, respectively, while all compounds did not show obvious cytotoxicity against tumor cell lines K562, A549, Hela, and Hep-2. Their structure-activity relationship was discussed. [ABSTRACT FROM AUTHOR]

Abstract: A chemical examination of the Chinese sponge Acanthella cavernosa resulted in the isolation of three new A-ring contracted steroids, the ethyl esters of 2β-hydroxy-4,7-diketo-A-norcholest-5-en-2-oic acid (1), 24S-ethyl-2β-hydroxy-4,7-diketo-A-norcholest-5-en-2-oic acid (2), and 2β-hydroxy-4,7-diketo-24R-methyl-A-norcholest-5,22(E)-dien-2-oic acid (3), along with four other known steroids (4–7). The structures were determined on the basis of extensive spectroscopic analysis. Compounds 1–3 showed antifouling activity toward the settlement inhibition of Balanus albicostatus with the EC50 values of 8.2, 23.5, 31.6μg/mL, respectively. [Copyright &y& Elsevier]

Patterns of recruitment in marine ecosystems can reflect the distribution of adults, dispersal by ocean currents, or patterns of mortality after settlement. In turn, patterns of recruitment can play an important role in determining patterns of adult abundance and community dynamics. Here we examine the biogeographic structure of recruitment variability along the U.S. West Coast and examine its association with temperature variability. From 1997 to 2004 we monitored monthly recruitment rates of dominant intertidal invertebrates, mussels and barnacles, at 26 rocky shore sites on the West Coast of the United States, from northern Oregon to southern California, a span of 1750 km of coastline. We examined spatial variation in the dynamics of recruitment rates and their relationship to coastal oceanography using satellite-derived time series of monthly sea surface temperature (SST). Recruitment rates showed a biogeographic structure with large regions under similar dynamics delimited by abrupt transitions. The seasonal peak in recruitment rates for both mussels and barnacles changed from a late summer-early fall peak in Oregon to winter or early spring in northern California, and then .back toward summer in southern California. Recruitment rates varied greatly in magnitude across the latitudinal range. The barnacle Balanus glandula and mussels (Mytilus spp.) showed a decline of two orders of magnitude south of Oregon. In contrast, recruitment rates of barnacles of the genus Chthamalus showed a variable pattern across the region examined. The spatial distribution of associations between raw SST and recruitment rates for all species showed positive associations, indicating recruitment during warm months, for all species in Oregon, northern California, and several sites in south-central California. By considerably extending the spatial and temporal scales beyond that of previous studies on larval recruitment rates in this system, our study has identified major biogeographic breaks around Cape Blanco and Point Conception despite considerable spatial and temporal variation within each region and among species. These large differences in recruitment rates across biogeographic scales highlight the need for a better understanding of larval responses to ocean circulation patterns in the conservation and management of coastal ecosystems. [ABSTRACT FROM AUTHOR]

The date of first introduction of the North-East Pacific acorn barnacle Balanus glandula to South Africa is unknown, but it is depicted in photographic records dating back to at least 1992. Its present range and population density were determined by surveying 24 sites on the west and south coasts of South Africa. B. glandula occurred over approximately 400 km of coastline, from Elands Bay in the north-west to Misty Cliffs on the west coast of the Cape Peninsula. The abundance of B. glandula was affected by site, zone, prevalence of upwelling, and orientation of the shore. Its distribution was very patchy, both on macro- and microscales, with Bloubergstrand and Moullie Point having the highest abundances of 28 445 and 24 500 individuals m-2 respectively. B. glandula was the dominant barnacle at all West Coast sites where it was recorded, comprising 78.5% of all barnacles found. The successful invasions of B. glandula in South Africa, Argentina and Japan suggest that this species poses a potential threat to intertidal communities in cool, temperate waters. [ABSTRACT FROM AUTHOR]

We report the occurrence of the North-East Pacific intertidal barnacle Balanus glandula in the south-western African shores of the Atlantic Ocean. In addition, an attempt is made to trace the origin of the South African population by comparing the distribution of haplotype groups of two molecular markers, cytochrome oxidase subunit I (COI) and elongation factor 1 (EF1-α). The frequency of COI haplotypes in the South African specimens was most similar to that in specimens from Bodega Marine Laboratory and of Fort Bragg in Central California. Pairwise genetic distances demonstrated that the samples from Pillar Point were also similar to the Cape Town population. The frequency of EF1-α haplotype groups from Cape Town was most similar to that of Cape Blanco, Cape Meares and Westport Jetty, and, with lower p-values, to the populations of Cape Mendocino and Heceta Head. Pairwise genetic distances demonstrated that samples from Vancouver Island, Bodega Marine Laboratory and Heceta Head were also similar to the Cape Town population. Results indicate that the population of B. glandula from South Africa is most similar to the population from the northern portion of the Oregonian faunal province. It is possible that this is the origin of the South African population. As a result of this invasion, B. glandula out-competed the native African chthamalid species, Chthamalus dentatus. Thus, C. dentatus is presently very rare on the Atlantic South African shores. [ABSTRACT FROM AUTHOR]

Gregariousness in marine invertebrate larvae is an important regulator of benthic community structure. Previous laboratory settlement assays employing Balanus amphitrite Darwin cyprids found gregarious effects with as few as 3 larvae well-1, together with modulation of such effects by chemical cues. Here, the relationship between settlement rate and larval density was rigorously tested through a fully randomised design. Seawater conditioned with adult B.amphitrite was tested alongside unconditioned seawater to determine the effect of a conspecific cue on gregarious interactions. Gregarious effects were detected in both conditioned and unconditioned seawater at ≤4 larvae well-1. In untreated seawater, settlement rate increased linearly with larval density, levelling off at densities of ≥10 larvae well-1. In conditioned seawater, settlement induction was observed at ≤4 larvae well-1, switching to inhibition at 6, 8 and 10 larvae well-1, before asymptoting at the highest densities tested. These results advocate the use of individual larvae in laboratory assays that investigate factors stimulating barnacle settlement. [ABSTRACT FROM AUTHOR]

The mechanical properties of barnacle base plates were measured using a punch test apparatus, with the purpose of examining the effect that the base plate flexural rigidity may have on adhesion mechanics. Base plate compliance was measured for 43 Balanus amphitrite (=Amphibalanus amphitrite) barnacles. Compliance measurements were used to determine flexural rigidity (assuming a fixed-edge circular plate approximation) and composite modulus of the base plates. The barnacles were categorized by age and cement type (hard or gummy) for statistical analyses. Barnacles that were 'hard' (≥70% of the base plate thin, rigid cement) and 'gummy' (>30% of the base plate covered in compliant, tacky cement) showed statistically different composite moduli but did not show a difference in base plate flexural rigidity. The average flexural rigidity for all barnacles was 0.0020 Nm (SEM ± 0.0003). Flexural rigidity and composite modulus did not differ significantly between 3-month and 14-month-old barnacles. The relatively low flexural rigidity measured for barnacles suggests that a rigid punch approximation is not sufficient to account for the contributions to adhesion mechanics due to flexing of real barnacles during release. [ABSTRACT FROM AUTHOR]

The regulation of the settlement process in barnacles has attracted research interest due to their role as fouling organisms. The involvement of neurotransmitters in the regulation of settlement of marine invertebrate larvae has been described in several species. In this work, we reported the effects of the neurotransmitters dopamine and serotonin on the settlement of cyprids of the barnacle Balanus improvisus and described differences among cyprids of different ages. Also, we tested the effects of dopaminergic and serotonergic agonists and antagonists on settlement of cyprid larvae. We found that dopamine significantly stimulated settlement of 2- and 4-day-old cyprids, while serotonin exerted an inhibitory effect, regardless of cyprid age. The agonists and antagonists to the two neurotransmitters were not able to stimulate settlement but in general had either an inhibitory or no effect. We compared our results to those previously reported of the roles of dopamine and serotonin in the settlement of Balanus amphitrite. There appeared to be striking differences in the effects of these neurotransmitters between the two species because it has been reported that serotonin induces settlement in B. amphitrite and that dopamine inhibits it. This suggested that dopamine and serotonin play pivotal roles in settlement of barnacle but may act in different ways in the two species. [ABSTRACT FROM AUTHOR]

In the intertidal zone in the Pacific Northwest, body temperatures of sessile marine organisms can reach 35°C for an extended time during low tide, resulting in potential physiological stress. We used immunochemical assays to examine the effects of thermal stress on endogenous Hsp70 levels in the intertidal barnacle Balanus glandula. After thermal stress, endogenous Hsp70 levels did not increase above control levels in B. glandula exposed to 20 and 28°C. In a separate experiment, endogenous Hsp70 levels were higher than control levels when B. glandula was exposed to 34°C for 8.5 h. Although an induced heat-shock response was observed, levels of conjugated ubiquitin failed to indicate irreversible protein damage at temperatures up to 34°C. With metabolic labeling, we examined temperature acclimation and thermally induced heat-shock proteins in B. glandula. An induced heat-shock response of proteins in the 70-kDa region (Hsp70) occurred in B. glandula above 23°C. This heat-shock response was similar in molting and non-molting barnacles. Acclimation of B. glandula to relatively higher temperatures resulted in higher levels of protein synthesis in the 70-kDa region and lack of an upward shift in the induction temperature for heat-shock proteins. Our results suggest that B. glandula may be well adapted to life in the high intertidal zone but may lack the plasticity to acclimate to higher temperatures. [ABSTRACT FROM AUTHOR]

Stable isotopic compositions of nitrogen and carbon in barnacles Balanus perforatus from the Pirovac Bay (Central Adriatic), highly impacted by untreated municipal waste, and from unaffected sites from the southern part of the Kornati Islands were compared. The differences in δ13C and δ15N values observed in organisms from both areas suggest that this benthic invertebrate could be a potential biomonitor for sewage-derived nutrients in coastal seas. Both nitrogen and carbon were enriched in heavy isotopes in organisms collected in Pirovac Bay, as well as in those from the area around the fish farm at Vrgada Island. These point toward an increased input of 15N and 13C enriched anthropogenic and/or aquaculture derived nitrogen and carbon into the local marine ecosystem. It is suggested that benthic filter feeders, such as B. perforatus, could be useful sentinels for detecting anthropogenically-derived inputs of nutrients into the coastal marine ecosystems. However, to get a better insight into the transfer rates of anthropogenic C and N into the food web, more extended research on a larger population is needed, as well as a detailed investigation of seasonal variation of abundance and isotopic composition of particulate organic matter as their presumed food source. [ABSTRACT FROM AUTHOR]

Analogues of insect juvenile hormones (juvenoids) have been tested for settling inhibition of cyprids from three species of barnacle, Balanus balanoides (L.), Balanus improvisus Darwin and Balanus amphitrite Darwin. Some 3-alkoxypyridine derivatives exhibited strong activity at mg litre-1 concentrations; 3,7-dimethyloctyl 2- methyl-5-pyridyl ether (8) gave an EC50 of 0.006 mg litre-1 when tested on B. balanoides. When compound 8 and similar juvenoids were incorporated into paints, test panels kept in seawater for S months were free of barnacles. [ABSTRACT FROM AUTHOR]

Cyprids are the final planktonic stage in the larval dispersal of barnacles and are responsible for surface exploration and attachment to appropriate substrata. The nanomechanical properties of barnacle ( Balanus amphitrite ) cyprid permanent cement were studied in situ using atomic force microscopy (AFM). Force curves were recorded from the cement disc continually over the course of its curing and these were subsequently analysed using custom software. Results showed a narrowing of the pull-off force distribution with time, as well as a reduction in molecular stretch length over time. In addition, there was a strong correlation between maximum pull-off force and molecular stretch length for the cement, suggesting ‘curing’ of the adhesive; some force curves also contained a ‘fingerprint’ of modular protein unfolding. This study provides the first direct experimental evidence in support of a putative ‘tanning’ mechanism in barnacle cyprid cement. [ABSTRACT FROM AUTHOR]

Shells of the blue mussel Mytilus edulis remain free of fouling organisms as long as they possess an intact periostracum, and a multiple antifouling defence that comprises a ripple-like microtopography and the production of chemical antifouling compounds has been suggested previously. This study investigates the chemical defence strategy of blue mussels for the first time. Six crude extracts of the periostracum of intact shells were made using solvents of increasing polarity. These extracts were tested against common fouling organisms in laboratory based bioassays. Non-polar and moderately polar fractions showed the highest activities: the diethyl ether fraction strongly inhibited attachment of Balanus amphitrite cyprids and the marine bacteria Cobetia marina and Marinobacter hydrocarbonoclasticus . Attachment of the benthic diatom Amphora coffeaeformis was significantly reduced by the dichloromethane extract, whereas both ethyl acetate and diethyl ether fractions slowed diatom growth. These results provide the first evidence of surface bound compounds that may moderate surface colonisation. [ABSTRACT FROM AUTHOR]

The potential driving force(s) of the vertical distribution of subtidal barnacle Balanus trigonus Darwin were investigated using both field and laboratory experiments. Early juveniles (∼24 h old) placed in intertidal [∼0.5 m above mean low water level (MLWL)] and subtidal (∼3 m below MLWL) habitats survived equally well, indicating that the intertidal absence of B. trigonus in Hong Kong waters was not determined by differential mortality. However, enhanced attachment of cyprids in subtidal habitats indicated the importance of differential larval choice in determining their vertical distribution. In the laboratory, cyprids preferred to attach in response to subtidal microbial films, which may implicate microbial films as a primary cue in driving the adult vertical distribution. Microbial films developed in these two habitats differed in their biomass (=total organic carbon), abundance of bacteria and diatoms (determined by fluorescence microscopy), and bacterial diversity (determined by DNA fingerprinting analysis). For example, 6-day films in subtidal habitat had a significantly higher biomass than in films from intertidal habitat ( P<0.05). There was no difference in the biomass of films from these two habitats in 9-day films ( P>0.05); however, bacterial abundance was greater in subtidal films than in intertidal films, irrespective of the age of the film, although there was no difference in diatom abundance in films from these two habitats. Neither the abundance of bacteria and diatoms nor the biomass correlated with the attachment preferences of cyprids. This study has not provided any data to prove the existence of inductive and inhibitive (to cyprid attachment) bacterial species in subtidal and intertidal films, respectively; however, results indicate that bacterial community provided qualitative information that might explain the preferential attachment of B. trigonus cyprids in subtidal habitat. [ABSTRACT FROM AUTHOR]

Barnacles, like many marine invertebrates, cause serious biofouling to marine industrial constructions and hulls of vessels as they attach themselves to such surfaces. Precise biochemical understanding of the underwater adhesion to surfaces requires a detailed characterization of the biology of the control of barnacle cement secretion and the proteins that make up the cement. In this study, we have investigated cement secretion by cyprid larvae of Balanus improvisus (D.) and the morphology of their cement glands. We studied the cement protein organization within cement granules and categorized the granules into four different types according to their size and morphology, before and after stimulation of secretion. In addition, we followed the exocytotic process of cement secretion in vivo and discovered that granules undergo a dramatic swelling during secretion. Such swelling might be due to an increased osmotic activity of granule contents, following a process of hydration. We hypothesize that this hydration is essential for exocytotic secretion and conclude that cement protein exocytosis is a more complex process than previously thought and is similar to exocytotic secretion in vertebrate systems, such as histamine secretion from mast cells and exocrine secretion in the salivary gland and the pancreas. [ABSTRACT FROM AUTHOR]

The ecological patterns of many invertebrate larvae remain an ongoing mystery, in large part owing to the difficult task of detecting them in the water column. The development of nucleic-acid–based technology has the potential to resolve this issue by direct identification and monitoring of embryonic and larval forms in situ. We report herein on the successful development and application of nucleic-acid–based sandwich hybridization assays that detect barnacles using rRNA-targeted probes with both group-(order Thoracica) and species-( Balanus glandula) specificity. Primary results include the determination of target 18S rRNA sequences and the construction of “capture” probes for detection of larvae using hybridization techniques. In addition, we modified existing protocols for whole cell hybridization of invertebrate larvae as confirmation of the sandwich hybridization results. We used both hybridization techniques successfully in the laboratory on a plankton time series collected over 3 months, as well as a week-long in situ deployment of the technique in Monterey Bay, CA. The adaptability of this technology promises to be further applicable to various organisms and could be used to enhance our understanding of larval presence in the world's oceans. [ABSTRACT FROM AUTHOR]

Post-copulatory behaviour in barnacles involves a violent rocking movement of the opercular valves, which is thought to contribute to the expulsion of oocytes through the oviduct into the mantle cavity where they are fertilised. We demonstrate in this study that the seminal vesicles/testis of the subtidal barnacle Balanus balanus produce a biologically active factor, barnacle muscle stimulatory factor (BMSF), which causes a significant increase in cirral and body muscular activity. BMSF was identified using a combination of high performance liquid chromatography and mass spectrometry as a novel eicosanoidloxylipin, 8,13-dihydroxyeicosapentaenoic acid. This is rapidly inactivated under mild acid conditions to form a complex range of triene and pentaene chromophore-containing products that have only been partially identified. Injection of purified BMSF into the mantle cavity of barnacles caused the rocking movements of the opercular valves as reported following fertilisation. In excised barnacles, it also caused muscular contractions of the whole body mass. The breakdown products of BMSF, however, were without such activities. The function of BMSF in facilitating fertilisation in barnacles is comparable to the role of other eicosanoids in human reproduction, reinforcing the view that these compounds have conserved activities in both invertebrates and vertebrates. [ABSTRACT FROM AUTHOR]

Abstract: Experiments were conducted to assess the effects of copper on larval development in the barnacle Balanus amphitrite. In the first experiment, we compared the sensitivity of three naupliar stages to copper stress. Molting inhibition occurred at copper concentrations ranging from 32μgl−1 in nauplius II to 128gl−1 in nauplius VI. EC50 for molting ranged from 97μgl−1 in nauplius II to 129gl−1 in nauplius VI. Decreased survival occurred at 128μgCul−1 in all of the naupliar stages tested, with LC50 ranging from 145 in nauplius II to 213μgl−1 in nauplius VI. In the second experiment, we examined effects of copper on the development from nauplius II to cyprid. The larvae reached cypris stage only in treatments of ⩽16μgCul−1. Our study therefore showed that molting was a more sensitive endpoint than survival, nauplius II was the most sensitive naupliar stage, and that whole larval development assay was more sensitive than assays using a particular larval stage. The results were discussed with respect to the use of this species in toxicity tests. [Copyright &y& Elsevier]

Theoretical and empirical research during the last decade suggests that increasing species richness often enhances ecosystem processes such as productivity, nutrient cycling, or resistance to disturbance. By analogous reasoning, it can be hypothesized that genetic diversity within species will have equivalent effects; however, this hypothesis has rarely been tested. We present experimental support for the positive effects of intraspecific diversity on a key trait: larval settlement in a marine invertebrate, the barnacle Balanus improvisus. Varying within-species diversity levels of an animal over nine experiments, we found increasing larval settlement with increasing diversity (one, two, or three parental broods). Possible mechanisms explaining this pattern include: (1) facilitation of gregarious response through the presence of founder genotypes, and (2) ensuring genetic complementarity to increase future reproductive potential. Our results indicate that changing intraspecific genetic diversity could have hitherto unrecognized community-scale implications for larval recruitment and space occupancy. [ABSTRACT FROM AUTHOR]

Planktonic larvae encounter variability in the marine environment as they develop, and rates of larval development are affected by changes in certain environmental variables. We examine the effects of variation in environmental parameters on the duration of the naupliar period of Balanus glandula larvae. Naupliar development rate is modeled as a function of temperature and food concentration. Simulations of the time course of development were driven by time series of temperature and food concentration collected at two locations on the US west coast. Predicted naupliar durations are reasonable in comparison to previous observations. Simulations of larval development and dispersal were driven by output of a three-dimensional physical circulation model and remotely sensed chlorophyll. These simulations demonstrate the impact of spatial variation in current velocity, temperature and chlorophyll on the duration of the larval period, the dispersal trajectory of these organisms and ultimately on recruitment success. Our naupliar development model coupled with a physical circulation model is a useful tool for addressing questions of intertidal population ecology. [ABSTRACT FROM AUTHOR]