Science.gov

Sample records for hydroid cordylophora caspia

  1. Controlling biofouling caused by the colonial hydroid Cordylophora caspia.

    PubMed

    Folino-Rorem, Nadine C; Indelicato, Jennifer

    2005-07-01

    The euryhaline hydroid, Cordylophora caspia, causes fouling problems in Europe and the United States. Researchers propose that this hydroid is becoming more prevalent in freshwater habitats as evidenced in Morris, IL where it was found clogging intake pipes and screens at a power plant, Midwest Generation's Collins Station. Our objective was to determine ways to curtail growth or kill C. caspia. Hydroid colonies in the laboratory were exposed to thermal treatments of 35, 36.1, 37.7, and 40.5 degrees C ranging from 1 to 8h. Hydroids did not survive at the two highest temperatures. Colonies exposed to lower temperatures exhibited varying degrees of survival relative to temperature and exposure time and demonstrated regeneration. In addition, experiments using chlorine were conducted using concentrations ranging from 0.2 to 5.0 mgl(-1). Chlorine experiments using exposure times of 105 min and three 20 min exposures in a 24h period did not kill colonies but were effective in curtailing growth. Thermal treatments are preferred because they are effective and result in less environmental impact in receiving waters than chemicals.

  2. Nematocysts of the invasive hydroid Cordylophora caspia (Cnidaria: Hydrozoa).

    PubMed

    Wollschlager, Jennifer; Folino-Rorem, Nadine; Daly, Marymegan

    2013-04-01

    Although there is significant genetic diversity among populations of the hydroid Cordylophora caspia, the species has not been split into multiple species or subspecies, in part because its members also show great physiological and morphological plasticity. This plasticity makes new taxonomic units hard to define or identify and obscures the connection between historically used names and the genetically defined clades. We explore variation in nematocysts, a character system not previously assessed in Cordylophora but which has demonstrated phylogenetic signal in other cnidarian taxa. We measured more than 5000 capsules from 112 individuals belonging to 14 populations, including representatives of the major genetic lineages. We found no correlation between the size range of capsules and either clade or salinity. Thus, for C. caspia, nematocysts are neither phenotypically plastic with respect to salinity nor taxonomically informative. Nematocyst size and density in particular tissues may be correlated to other environmental factors (such as prey type, size, and abundance in the location of each population) and may aid in distinguishing more distantly related species.

  3. Salinity dependence of vanadium toxicity against the brackish water hydroid Cordylophora caspia.

    PubMed

    Ringelband, U

    2001-01-01

    Vanadium, an abundant metal, enters the environment through natural rock weathering or by combustion of oil products. A third pathway is the leaching of vanadium-rich building materials. Stones made from steel industry residual slags, so-called slag stones, contain rather large amounts of vanadium. The increasing use of these slag stones in riverbank reinforcement has therefore led to increased interest in the toxicity of vanadium to aquatic organisms. The aim of the study was to determine the toxicity of vanadium to the brackish water hydroid Cordylophora caspia and the effect of vanadium on the membrane-bound enzyme Na, K-ATPase at various salinities. EC50 values for population growth inhibition were determined from 1.74 to 7.96 mg x L(-1) vanadium, depending on salinity. The maximum inhibition of population growth by vanadium was observed at low salinities. Correspondingly, maximum Na, K-ATPase inhibition was also measured at low salinities and decreased with increasing salinity. The present study suggests that the observed inhibition of population growth of C. caspia caused by vanadium-contaminated rearing water is due to the vanadium-induced inhibition of phosphatases.

  4. Effects of vanadium on population growth and Na-K-ATPase activity of the brackish water hydroid Cordylophora caspia

    SciTech Connect

    Ringelband, U.; Karbe, L.

    1996-07-01

    Vanadium, a relatively abundant heavy metal, enters the environment naturally through rock weathering. A large fraction of vanadium input is of human origin. The combustion of petroleum- and coal-products, which contain relatively high concentrations of vanadium, is one of the most important sources of the enrichment of vanadium in the environment. As it is used as an alloy, and vanadium rich iron-ores of various origin are used in steel production, the residual slag-stones of the steel industry can contain considerable vanadium concentrations. Wherever slag-stones serve as a cheap and convenient material in riverbank reinforcement, vanadium can leach into the aquatic environment. Vanadium is regarded as an essential trace element for higher animals. Cantley et al. indicated a regulatory function of vanadate in vivo. Although considerable information is available on the toxic effects of vanadium on humans, very little is known about the toxicity of vanadium towards aquatic organisms, especially invertebrates. Bell and Sargent have shown an inhibition of Na-K-ATPase activity in gills of the eel Anguilla anguilla. Holleland and Towle have demonstrated the inhibition of Na-K-ATPase activity in the gills of the shore crab Carcinus maenas. The aim of this study was to determine the toxicity of vanadium towards the brackish water hydroid Cordylophora caspia. Hydroids are known to be particularly sensitive to heavy metals and their asexual reproduction can be used in a well-established population growth test. Furthermore, the effects of vanadium on Na-K-ATPase activity in hydroids were studied in in vivo experiments, wherein the animals were exposed to sublethal concentrations of vanadium. In addition, the inhibition of Na-K-ATPase was measured in vitro, by adding vanadium to a microsomal preparation. 16 refs., 4 figs.

  5. Microsatellite loci for the invasive colonial hydrozoan Cordylophora caspia

    EPA Science Inventory

    Cordylophora caspia, a colonial hydrozoan native to the Ponto-Caspian region, has become a common invader of both fresh and brackish water ecosystems of North America and Europe. Here we describe 11 polymorphic microsatellite loci for this species. Preliminary analyses indicate ...

  6. Microsatellite loci for the invasive colonial hydrozoan Cordylophora caspia

    EPA Science Inventory

    Cordylophora caspia, a colonial hydrozoan native to the Ponto-Caspian region, has become a common invader of both fresh and brackish water ecosystems of North America and Europe. Here we describe 11 polymorphic microsatellite loci for this species. Preliminary analyses indicate ...

  7. Invasive Ponto-Caspian hydrozoan Cordylophora caspia (hydrozoa: Cnidaria) in southern Baltic coastal lakes

    NASA Astrophysics Data System (ADS)

    Obolewski, Krystian; Jarosiewicz, Anna; Ożgo, Małgorzata

    2015-12-01

    Cordylophora caspia Pall. is a highly invasive Ponto-Caspian colonial hydroid with a worldwide distribution. It is a biofouling organism colonizing industrial water installations and causing serious economic problems. Here, we give the first report of its occurrence in southern Baltic coastal lakes, and analyze its distribution in relation to environmental factors and likely colonization routes. Samples were collected from the stalks of Phragmites australis at the total of 102 sites in 15 lakes and lagoons. The species was most numerous in lagoons, i.e. ß-oligohaline water bodies with a surface hydrological connection with the sea, where it reached mean densities of 1200-4800 hydranths m-2. In regression tree analysis, chloride concentration, followed by pH, were the strongest explanatory variables for its occurrence, with highest densities observed at chloride concentration above 1.18 g Cl L-1 and pH 8.05-9.26. At pH 5.77-8.04 higher densities were observed at temperatures above 20.3 °C. Generally, within the range of parameters observed in our study, high densities of C. caspia were associated with high chloride concentration, pH, temperature and electrical conductivity values. The species was also present in freshwater lakes; these colonies may have the highest capacity for future invasions of such habitats. Within lakes, high densities were observed at canals connecting these water bodies with the sea, and at sites close to the inflow of rivers. This distribution pattern can facilitate its further spread into inland waters.

  8. Proline Control of the Feeding Reaction of Cordylophora

    PubMed Central

    Fulton, Chandler

    1963-01-01

    The colonial hydroid Cordylophora is a carnivore whose feeding is induced by substances released from captured prey. An active molecule, probably the only one, has been isolated from a fraction of the laboratory food of Cordylophora, brine shrimp larvae, and identified on paper chromatograms as the imino acid proline. Reagent proline induces the feeding reaction at 10-5 M. The reaction is specific in that only two α-imino acids very closely related to proline were found to possess significant activity: azetidine-2-carboxylic acid and pipecolic acid. The response to proline is inhibited by magnesium ions and enhanced by phosphate. Since previous studies have shown that the feeding reactions of Hydra, Physalia, and Campanularia are controlled by reduced glutathione, the phylogenetic implications of the proline control of feeding in Cordylophora are discussed. The feeding reactions of both Cordylophora and Hydra are also induced by proteases, suggesting similar mechanisms of induction in the two hydroids. PMID:13960251

  9. Drag on hydroid-fouled nets — An experimental approach

    NASA Astrophysics Data System (ADS)

    Lader, Pål; Fredriksson, David W.; Guenther, Jana; Volent, Zsolt; Blocher, Nina; Kristiansen, David; Gansel, Lars; Decew, Jud

    2015-06-01

    The present study investigated the drag increase on aquaculture nets due to biofouling of the colonial hydroid Ectopleura larynx. It had two main parts: firstly the growth characteristics of E. larynx were investigated by use of field tests at a Norwegian aquaculture site; secondly the hydrodynamic drag on the fouled twines was studied in a towing tank by using fabricated models of net twines with artificial hydroid fouling. In the field tests, the growth of the hydroids was first measured after three weeks of immersion and then again after six weeks. During this interval, the density of hydroids and the thickness of the hydroid stem were almost constant (1.4 hydroids/mm and 0.29 mm, respectively), while the average length of the hydroids increased from 6.4 to 11.2 mm. The hydroid length followed a Rayleigh distribution, while the thickness was normal (Gaussian) distributed. Replicas of twines with three different levels of hydroid growth were made (1.5 hydroids/mm twine, hydroid length 9 mm, 16 mm and 20 mm), and the drag on these twines was measured at different towing velocities (0.1 to 1.4 m/s) and with different twine configurations. For the twine with the shortest hydroids (9 mm), the drag was from 1.5 times ( Re=4000) to 2.2 times ( Re=1000) the drag on a clean twine. For the longest hydroids (21 mm), the drag was 2 times and 3.8 times, respectively.

  10. Shared Skeletal Support in a Coral-Hydroid Symbiosis

    PubMed Central

    Pantos, Olga; Hoegh-Guldberg, Ove

    2011-01-01

    Hydroids form symbiotic relationships with a range of invertebrate hosts. Where they live with colonial invertebrates such as corals or bryozoans the hydroids may benefit from the physical support and protection of their host's hard exoskeleton, but how they interact with them is unknown. Electron microscopy was used to investigate the physical interactions between the colonial hydroid Zanclea margaritae and its reef-building coral host Acropora muricata. The hydroid tissues extend below the coral tissue surface sitting in direct contact with the host's skeleton. Although this arrangement provides the hydroid with protective support, it also presents problems of potential interference with the coral's growth processes and exposes the hydroid to overgrowth and smothering. Desmocytes located within the epidermal layer of the hydroid's perisarc-free hydrorhizae fasten it to the coral skeleton. The large apical surface area of the desmocyte and high bifurcation of the distal end within the mesoglea, as well as the clustering of desmocytes suggests that a very strong attachment between the hydroid and the coral skeleton. This is the first study to provide a detailed description of how symbiotic hydroids attach to their host's skeleton, utilising it for physical support. Results suggest that the loss of perisarc, a characteristic commonly associated with symbiosis, allows the hydroid to utilise desmocytes for attachment. The use of these anchoring structures provides a dynamic method of attachment, facilitating detachment from the coral skeleton during extension, thereby avoiding overgrowth and smothering enabling the hydroid to remain within the host colony for prolonged periods of time. PMID:21695083

  11. Biofouling by bryozoans, Cordylophora and sponges in UK water treatment works.

    PubMed

    Mant, R C; Moggridge, G; Aldridge, D C

    2011-01-01

    In recent years biofouling from native (bryozoans, sponges) and non-native (Cordylophora) animals has increased in UK water treatment works (WTW). A survey of six UK water companies and eight WTWs revealed that these taxa were more widespread and abundant than previously recognised. Primary problems related to the occlusion of underfloor nozzles and tailpipes in rapid gravity filter beds (RGFs). These cost the UK water industry pound 1.49 m between 2005 and 2009. Additional impacts came from skin irritation to operatives from sponge spicules and the potential for elevated bacterial pathogen levels. Sponges penetrated the furthest through the water treatment process, reaching the point of final chlorination at one WTW. A monitoring plate study showed pronounced seasonality in fouling, with most taxa peaking in mid to late summer before a winter die-off. Control options, including the use of chlorine, and the importance of resistant stages for each taxon are discussed.

  12. [Morphogenetic foundations for increased evolutionary complexity in the organization of thecate hydroids shoots (Cnidaria, Hydroidomedusa, Leptomedusae)].

    PubMed

    Kosevich, I A

    2012-01-01

    The morphogenetic approach is applied to analyze the diversity of spatial organization of shoots in thecate hydroids (Cnidaria, Hydroidomedusa, Leptomedusae). The main tendencies and constraints of increased evolutionary complexity in thecate hydroids colonies are uncovered.

  13. Totipotent migratory stem cells in a hydroid.

    PubMed

    Müller, Werner A; Teo, Regina; Frank, Uri

    2004-11-01

    Hydroids, members of the most ancient eumetazoan phylum, the Cnidaria, harbor multipotent, migratory stem cells lodged in interstitial spaces of epithelial cells and are therefore referred to as interstitial cells or i-cells. According to traditional understanding, based on studies in Hydra, these i-cells give rise to several cell types such as stinging cells, nerve cells, and germ cells, but not to ectodermal and endodermal epithelial cells; these are considered to constitute separate cell lineages. We show here that, in Hydractinia, the developmental potential of these migratory stem cells is wider than previously anticipated. We eliminated the i-cells from subcloned wild-type animals and subsequently introduced i-cells from mutant clones and vice versa. The mutant donors and the wild-type recipients differed in their sex, growth pattern, and morphology. With time, the recipient underwent a complete conversion into the phenotype and genotype of the donor. Thus, under these experimental conditions the interstitial stem cells of Hydractinia exhibit totipotency.

  14. Voracious planktonic hydroids: unexpected predatory impact on a coastal marine ecosystem

    NASA Astrophysics Data System (ADS)

    Madin, Laurence P.; Bollens, Stephen M.; Horgan, Erich; Butler, Mari; Runge, Jeffrey; Sullivan, Barbara K.; Klein-Macphee, Grace; Durbin, Edward; Durbin, Ann G.; Van Keuren, Donna; Plourde, Stéphane; Bucklin, Ann; Elizabeth Clarke, M.

    Hydroids are typically attached, benthic cnidarians that feed on a variety of small prey. During sampling on Georges Bank in spring 1994, we found huge numbers of hydroids suspended in the plankton. They fed on young stages of copepods that are an important prey for fish, as well as on young fish themselves. Two independent methods were used to estimate feeding rates of the hydroids; both indicate that the hydroids are capable of consuming from 50% to over 100% of the daily production of young copepods. These results suggest that hydroids can have a profound effect on the population dynamics of zooplankton and young fish on Georges Bank.

  15. Two bathyal hydroids (Hydrozoa: Leptothecata) from the Southwest Indian Ocean.

    PubMed

    Watson, Jeanette E

    2017-03-27

    Two species of hydroids were recovered from a mooring rope and experimentally deployed whale bone attached to an underwater transponder buoy at a depth of 732 m on the Coral Seamount on the Southwest Indian Ocean Ridge (41° 22.31'S, 54° 57'E) in the Southern Indian Ocean. The material was collected approximately 1,500 km south south-east of Madagascar during Voyage JC066 of the British Royal Research Ship R.R.S. James Cook on 20/11/2011. Hydroids were collected from the mooring rope and whale bone on board the ship after underwater retrieval by ROV.

  16. Anthoathecatae and Leptothecatae hydroids from Costa Rica (Cnidaria: Hydrozoa).

    PubMed

    Kelmo, Francisco; Vargas, Rita

    2002-06-01

    This paper is the first taxonomic account of the hydroid orders Anthoathecatae and Leptothecatae from the Caribbean and Pacific coast of Costa Rica. All specimens are currently stored at the reference collection of the Museo de Zoología, Escuela de Biología, Universidad de Costa Rica. Sixteen hydroid species are recorded: Eudendrium carneum, Pennaria disticha, Acryptolaria longitheca, Plumularia floridana, Halopteris polymorpha, Aglaophenia dubia, Aglaophenia latecarinata, Lytocarpia tridentata, Macrorhynchia phillipina, Macrorhynchia sp., Clytia gracilis, Cnidoscyphus marginatus, Thyroscyphus ramosus, Dynamena disticha, Sertularella diaphana, and Tridentata distans. An extensive synonymy has been given for each species. A simplified taxonomic key is included, and illustrations and descriptions are provided for each species.

  17. Genetic analysis across different spatial scales reveals multiple dispersal mechanisms for the invasive hydrozoan Cordylophora in the Great Lakes.

    PubMed

    Darling, John A; Folino-Rorem, Nadine C

    2009-12-01

    Discerning patterns of post-establishment spread by invasive species is critically important for the design of effective management strategies and the development of appropriate theoretical models predicting spatial expansion of introduced populations. The globally invasive colonial hydrozoan Cordylophora produces propagules both sexually and vegetatively and is associated with multiple potential dispersal mechanisms, making it a promising system to investigate complex patterns of population structure generated throughout the course of rapid range expansion. Here, we explore genetic patterns associated with the spread of this taxon within the North American Great Lakes basin. We collected intensively from eight harbours in the Chicago area in order to conduct detailed investigation of local population expansion. In addition, we collected from Lakes Michigan, Erie, and Ontario, as well as Lake Cayuga in the Finger Lakes of upstate New York in order to assess genetic structure on a regional scale. Based on data from eight highly polymorphic microsatellite loci we examined the spatial extent of clonal genotypes, assessed levels of neutral genetic diversity, and explored patterns of migration and dispersal at multiple spatial scales through assessment of population level genetic differentiation (pairwise F(ST) and factorial correspondence analysis), Bayesian inference of population structure, and assignment tests on individual genotypes. Results of these analyses indicate that Cordylophora populations in this region spread predominantly through sexually produced propagules, and that while limited natural larval dispersal can drive expansion locally, regional expansion likely relies on anthropogenic dispersal vectors.

  18. Distribution, abundance and benthic-pelagic coupling of suspended hydroids on Georges Bank1, 2

    NASA Astrophysics Data System (ADS)

    Concelman, Stephanie; Bollens, Stephen M.; Sullivan, Barbara K.; Madin, Laurence P.; Horgan, Erich; Butler, Mari; van Keuren, Donna

    Clytia spp. hydroids (Phylum Cnidaria), typically attached to a substrate during their asexual, polyp stage, have been found in significant numbers within the mesozooplankton on Georges Bank, North Atlantic Ocean. We examined unpublished historical records of the 1939-1941 cruises of the R/V Atlantis and obtained samples at four-study sites on Georges Bank in June/July 1995 in an attempt to (1) quantify the planktonic and benthic distributions of hydroids on Georges Bank, and (2) determine the coupling between benthic and pelagic habitats of this population. We found that planktonic hydroids have a patchy distribution, varying both spatially and temporally (most abundant in summer months, absent in winter). In 1939-1941 the planktonic hydroids were most broadly distributed following a spring (1940) with strong wind events; hydroids were absent from all samples in 1941. In 1995 we found the highest abundance of planktonic Clytia spp. hydroids (6213.5±1343.6 hydranths m -3) in the central crest of the bank, "downstream" in the Georges Bank circulation pattern from sites along the northeast peak of the Bank where large populations of benthic Clytia spp. hydroids were found (up to 6465 hydranths m -2). Our plankton sampling did not show significant numbers of hydroids in the water column at the Northeast peak sites, indicating that large numbers of planktonic hydroids are not being introduced into the Bank's circulation patterns from off-Bank sites to the northeast (e.g. Scotian shelf). The source population for planktonic hydroids found in the central region of the Bank is most likely the benthic habitats on the northeast peak of the Bank. We hypothesize, and our limited data suggest, that hydroids are detached from the benthos by storm action or other disturbance, advected clockwise with the mean residual circulation, and concentrated and retained in the central, low-advective region of the Bank.

  19. Planktonic hydroids on Georges Bank: ingestion and selection by predatory fishes1

    NASA Astrophysics Data System (ADS)

    Avent, Sean R.; Bollens, Stephen M.; Butler, Mari; Horgan, Erich; Rountree, Rodney

    Planktonic colonial hydroids ( Clytia gracilis) recently have been found to be abundant, but patchily distributed in time and space, on Georges Bank, northwest Atlantic Ocean. However, the processes regulating the occurrence of these hydroid colonies (i.e., seasonality, growth, advection, diffusion, sinking, and predation) are not well understood. The objective of this study was to identify and quantify the potential role of predation by fish upon the unattached hydroids. The two components of this study were (i) analyses of historical fish trawl surveys and stomach contents data collected in the coastal northwest Atlantic Ocean (including Georges Bank), and (ii) laboratory experiments testing for the presence of selective feeding by juvenile cod ( Gadus morhua) on hydroids relative to two co-occurring planktonic copepods ( Calanus finmarchicus and Centropages hamatus). We found that 32 and 11 species of fish ingested hydroids in the coastal northwest Atlantic Ocean and Georges Bank, respectively, during 1973-1990. However, hydroids were rarely an important part of the diet of these fishes. The most important predator of these cnidarians on Georges Bank was winter flounder, with 28.0% of its population having ingested hydroids, with a mean % (by weight) of hydroids in the diet of 4.1%, during 1973-80. Laboratory experiments indicated juvenile cod ingested planktonic hydroids, but overwhelmingly preferred either of the two copepods as prey. While field and laboratory results indicated that a wide variety of fishes feed on hydroids, we concluded that emergences and disappearances of planktonic hydroids on Georges Bank are not greatly impacted by fish predation. Other factors, in particular physical processes (i.e., advection, diffusion, and sinking), seasonal cycles of activity and inactivity, and predation by invertebrates, should be examined.

  20. Control of Hydroid Colony Form by Surface Heterogeneity

    PubMed Central

    Buss, Leo W.; Buss, Evan D.; Anderson, Christopher P.; Power, Michael; Zinter, Joseph

    2016-01-01

    The colonial hydroid Podocoryna carnea grows adherent to surfaces progressing along them by a motile stolon tip. We here ask whether the stolon tip grows preferentially within grooves etched in silicon wafers. In a series of pilot experiments, we varied the dimensions of grooves and found that stolons did not utilize grooves with a width:depth of 5:5 μm or 10:10 μm, occasionally followed grooves 25:25 μm in size, and preferentially grew within grooves of a width:depth of 50:50 μm and 100:50 μm. We then grew colonies in grids, with fixed 50:50 μm width:depth channels intersecting at 90° every 950, 700, 450, or 150 μm. We find that stolons grew within grooves early in colony ontogeny, but remained restricted to them only in the grid pattern with channel intersections every 150 μm. Finally, we created a grid in the shape of the Yale Y logo, with channels of 50:50 μm width:depth and intersections every 100 μm. The resulting colonies conformed to that of the logo. Our findings demonstrate that stolons respond to surface heterogeneity and that surface etching can be used to fabricate microfluidic circuits comprised of hydroid perisarc. PMID:27257948

  1. Revision of the genus Hydroides (Annelida: Serpulidae) from Australia.

    PubMed

    Sun, Yanan; Wong, Eunice; ten Hove, Harry A; Hutchings, Pat A; Williamson, Jane E; Kupriyanova, Elena K

    2015-09-01

    Hydroides Gunnerus, 1768 is the largest and one of the economically most important genera of calcareous tubeworms (Serpulidae, Annelida) that includes a number of notorious fouling and bioinvading species. Although the representatives of the genus are typically found in shallow waters of tropical and subtropical areas worldwide, the species composition of the genus in Australia has never been revised. We conducted the first detailed regional taxonomic revision of Hydroides species based both on the historical collections from Australian museums (Australian Museum, Museum Victoria, South Australian Museum, Western Australian Museum, Queensland Museum, and Museum and Art Gallery of Northern Territory) and newly collected material from New South Wales, Victoria, Queensland, Northern Territory, and Western Australia. In total, 25 species are currently considered valid in Australia, including three new species: H. amri n. sp. from NSW, SA, and Vic (previously referred to as H. cf. brachyacantha), as well as H. glasbyi n. sp. and H. qiui n. sp., both from NT, and two new records of H. furcifera and H. multispinosa for Australia. We have synonymised H. spiratubus with H. albiceps, and H. spiculitubus with H. tambalagamensis in this study. The status of the taxon H. cf. recta remains undecided. An identification key and diagnoses accompanied by original high-quality photographs for all species recorded in Australia are provided. Application of molecular genetics is needed to resolve the status of some problematic species.

  2. Invaders eating invaders: Exploitation of novel alien prey by the alien shimofuri goby in the San Francisco Estuary, California

    USGS Publications Warehouse

    Matern, S.A.; Brown, L.R.

    2005-01-01

    The shimofuri goby (Tridentiger bifasciatus), which is native to Asian estuaries, was recently introduced to the San Francisco Estuary, California, USA. We conducted gut content analyses to examine the goby's feeding ecology in this highly invaded estuary. Shimofuri gobies were generalist predators on benthic invertebrates, consuming seasonally abundant prey, especially amphipods (Corophium spp.). In addition, shimofuri goby utilized two novel prey items not exploited by other resident fishes - hydroids (Cordylophora caspia) and barnacle (Balanus improvisus) cirri, both of which are alien. The shimofuri goby's feeding ecology appears well-suited to the fluctuating environment of the San Francisco Estuary and may partially explain observed increases in shimofuri goby abundance compared with declines in populations of some native species. ?? Springer 2005.

  3. Changes in the patterning of a hydroid colony.

    PubMed

    Kosevich, Igor A

    2006-01-01

    It is a widely held view that colonial hydroids (Cnidaria, Hydroidomedusae) are formed on the basis of a repetition of uniform elements. The dominant opinion is that the equal spatial organisation of the colony exists during all stages of its development except the primary polyp, which develops from the settled larva. However, the complex structure and large dimensions of shoots in certain thecate species (subcl. Leptomedusae) suggest that the organisation of the primary shoot differs strongly from that of established colonies. The present study based on a thorough collection and examination of the collected material allowed to describe the entire sequence of the colony ontogeny in Hydrallmania falcata (Sertulariidae). The established shoots of this species are characterised by relatively large size, spiral arrangement of pinnate branches over the shoot stem, and hydranths arranged in one row along the upper side of branches. We showed that the primary shoot developing from the larva has much smaller dimensions and an alternate arrangement of hydranths. During further colony development the shoot organisation undergoes a gradual transformation ending with the emergence of large shoots with 'characteristic' species-specific features. The discovered sequence of changes in shoot patterning shows certain correlations with alterations of the growing tip dimensions. The dimensions of the growing tip seem to determine the patterning in accordance with the particular spatial location of the tip. This finding implies the necessity of a detailed reinvestigation of the entire colony development in thecate hydroids, which would make a significant contribution to the understanding of the morphogenetic evolution and patterning mechanisms within this group of colonial organisms.

  4. Planktonic hydroids on Georges Bank: effects of mixing and food supply on feeding and growth1

    NASA Astrophysics Data System (ADS)

    Bollens, Stephen M.; Horgan, Erich; Concelman, Stephanie; Madin, Laurence P.; Gallager, Scott M.; Butler, Mari

    Huge numbers of hydroids (principally Clytia gracilis) were recently reported suspended in the plankton over the shallow, well-mixed region of Georges Bank, where preliminary feeding experiments suggested that these planktonic predators could have a potentially devastating effect on their zooplankton prey (Madin et al., 1996). Based on these initial findings we undertook a more extensive set of laboratory experiments examining the effects of particulate food concentration and mixing (turbulence) intensity on the feeding and growth of suspended hydroids. Not surprisingly, we found a clear effect of particulate food concentration on the growth of hydroid colonies. After 7 days at 15°C, both colony size (number of hydranths colony -1) and specific growth rate (hydranth hydranth -1 day -1) were significantly greater in well-fed (80-160 Artemia nauplii L -1) versus starved treatments. More interesting was the additional significant effect of turbulent mixing ( ɛ=9×10 -5 W kg -1) on hydroid growth. Consumption rates (4.5 Artemia nauplii hydranth -1 day -1) were not significantly different between mixing vs. non-mixing treatments, indicating that the enhanced growth rate in the mixing treatments could not have been due to turbulence-enhanced predator-prey contact rates. An alternative hypothesis for the apparent advantage that mixing seemed to confer on hydroid growth is that reduced boundary layer thickness around the hydroids served to replenish the local supply of DOM and oxygen and/or remove waste products. This study indicates that growth rate of planktonic hydroids is dependent on both food concentration and mixing intensity, a finding that helps explain why these organisms are vastly more abundant in the central, shallow, well-mixed region of Georges Bank compared to the stratified flanks of the Bank.

  5. Stepwise metamorphosis of the tubeworm Hydroides elegans is mediated by a bacterial inducer and MAPK signaling

    PubMed Central

    Shikuma, Nicholas J.; Antoshechkin, Igor; Medeiros, João M.; Pilhofer, Martin; Newman, Dianne K.

    2016-01-01

    Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control. PMID:27551098

  6. Stepwise metamorphosis of the tubeworm Hydroides elegans is mediated by a bacterial inducer and MAPK signaling.

    PubMed

    Shikuma, Nicholas J; Antoshechkin, Igor; Medeiros, João M; Pilhofer, Martin; Newman, Dianne K

    2016-09-06

    Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control.

  7. Helpful habitant or pernicious passenger: interactions between an infaunal bivalve, an epifaunal hydroid and three potential predators.

    PubMed

    Manning, Lisa M; Lindquist, Niels

    2003-02-01

    The importance of positive interspecific interactions within physically stressful habitats has received increased attention from community ecologists. The exposed sandy beach is an example of a physically rigorous environment where biological interactions have long been considered insignificant. We examined the interaction between the infaunal clam, Donax variabilis, and the hydroid, Lovenella gracilis, on exposed sandy beaches in North Carolina. Epibiotic occupation of Donax by hydroids has been repeatedly observed on ocean beaches but rarely investigated. By providing a stable substrate for attachment, the clam facilitates the persistence of the hydroid in the intertidal beach; however, benefits or costs experienced by the host as a result of this association are unknown. By exposing clams with and without hydroid colonies to multiple types of clam predators, we tested the effectiveness of the hydroid, which possesses stinging nematocysts, in defending its host. The hydroid defended the clam against one common predator, the Florida pompano ( Trachinotus carolinus). Against speckled crabs ( Arenaeus cribrarius) and ghost crabs ( Ocypode quadrata), however, the hydroid offered no protection for its host and instead facilitated predation. The epibiotic hydroid, which projects above the surface of the sand, allowed the crabs to more readily detect clams below the surface. In the field, we evaluated the effect of the hydroid on the tidally synchronized migrations and burrowing speed of the clam. The hydroid, which can form large colonies on the posterior end of the clam, had no effect on Donax burrowing speed, but did reduce the speed of transport of clams by wave swash. Depending on relative predation pressure, the occupation of D. variabilis by L. gracilis can alternately be characterized as beneficial or detrimental to the host.

  8. Hydroides Gunnerus, 1768 (Annelida, Serpulidae) is feminine: a nomenclatural checklist of updated names

    PubMed Central

    Read, Geoffrey B.; ten Hove, Harry A.; Sun, Yanan; Kupriyanova, Elena K.

    2017-01-01

    Abstract As a service to taxonomists and ecologists using names in the well-known and species-rich ship-fouling serpulid genus Hydroides we present an update of all 107 non-synonymised scientific names, with additional information on Hydroides nomenclature, original names, etymologies, and type localities derived from original literature, and in accord with the World Register of Marine Species (WoRMS) database. An update is needed because the gender of genus Hydroides has from 1 January 2000 reverted to the original feminine, due to a change in the wording of International Code of Zoological Nomenclature which was overlooked at that time, and is contrary to the usage in practice of Hydroides as masculine which had started about 1992, although Code-required from the 1960s. We match 31 further original names of current WoRMS subjective junior synonyms to each non-synonymised name, and also report on the world distribution of the genus as illustrated by type localities of the valid names. We include notes on seven species inquirenda. The correct rendering is given of six names that have been altered for gender agreement for the first time herein. Hydroides gottfriedi nom. n. replaces junior homonym Hydroides rostrata Pillai, 1971. Currently there are 41 non-synonymised species-group names in Hydroides which should be gender invariant, and 23 names which would only change if moved to a neuter genus; the remaining 43 names are fully gender variable. Place-names (23), and personal names (16) make up more than a third (36%) of the species names, with most of the remainder (68) being descriptive of species character states, usually of operculum morphology (54). All species, except Hydroides norvegica (63°N), have type localities in shallow-water coastal locations in temperate to tropical waters below latitude 44°, with the highest number of new species (54) from the adjoining Western Pacific and Indian Ocean areas. The other concentration of new species (31) are those

  9. Evolutionary genetics of the hydroid allodeterminant alr2.

    PubMed

    Gloria-Soria, Andrea; Moreno, Maria A; Yund, Philip O; Lakkis, Fadi G; Dellaporta, Stephen L; Buss, Leo W

    2012-12-01

    We surveyed genetic variation in alr2, an allodeterminant of the colonial hydroid Hydractinia symbiolongicarpus. We generated cDNA from a sample of 239 Hydractinia colonies collected at Lighthouse Point, Connecticut, and identified 473 alr2 alleles, 198 of which were unique. Rarefaction analysis suggested that the sample was near saturation. Most alleles were rare, with 86% occurring at frequencies of 1% or less. Alleles were highly variable, diverging on average by 18% of the amino acids in a predicted extracellular domain of the molecule. Analysis of 152 full-length alleles confirmed the existence of two structural types, defined by exons 4-8 of the gene. Several residues of the predicted immunoglobulin superfamily-like domains display signatures of positive selection. We also identified 77 unique alr2 pseudogene sequences from 85 colonies. Twenty-seven of these sequences matched expressed alr2 sequences from other colonies. This observation is consistent with pseudogenes contributing to alr2 diversification through sequence donation. A more limited collection of animals was made from a distant, relict population of H. symbiolongicarpus. Sixty percent of the unique sequences identified in this sample were found to match sequences from the Lighthouse Point population. The large number of alr2 alleles, their degree of divergence, the predominance of rare alleles in the population, their persistence over broad spatial and temporal scales, and the signatures of positive selection in multiple residues of the putative recognition domain paint a consistent picture of negative-frequency-dependent selection operating in this system. The genetic diversity observed at alr2 is comparable to that of the most highly polymorphic genetic systems known to date.

  10. Green Fluorescence of Cytaeis Hydroids Living in Association with Nassarius Gastropods in the Red Sea

    PubMed Central

    Prudkovsky, Andrey A.; Ivanenko, Viatcheslav N.; Nikitin, Mikhail A.; Lukyanov, Konstantin A.; Belousova, Anna; Reimer, James D.; Berumen, Michael L.

    2016-01-01

    Green Fluorescent Proteins (GFPs) have been reported from a wide diversity of medusae, but only a few observations of green fluorescence have been reported for hydroid colonies. In this study, we report on fluorescence displayed by hydroid polyps of the genus Cytaeis Eschscholtz, 1829 (Hydrozoa: Anthoathecata: Filifera) found at night time in the southern Red Sea (Saudi Arabia) living on shells of the gastropod Nassarius margaritifer (Dunker, 1847) (Neogastropoda: Buccinoidea: Nassariidae). We examined the fluorescence of these polyps and compare with previously reported data. Intensive green fluorescence with a spectral peak at 518 nm was detected in the hypostome of the Cytaeis polyps, unlike in previous reports that reported fluorescence either in the basal parts of polyps or in other locations on hydroid colonies. These results suggest that fluorescence may be widespread not only in medusae, but also in polyps, and also suggests that the patterns of fluorescence localization can vary in closely related species. The fluorescence of polyps may be potentially useful for field identification of cryptic species and study of geographical distributions of such hydroids and their hosts. PMID:26840497

  11. Zygophylax kakaiba, a new species of hydroid (Cnidaria: Hydrozoa:
    Zygophylacidae) from the Philippine Islands.

    PubMed

    Campos, Felipe Ferreira; Marques, Antonio Carlos; Puce, Stefania; Pérez, Carlos Daniel

    2016-03-09

    The genus Zygophylax Quelch, 1885 includes ca. 50 valid species of leptothecate hydroids that occur mainly in deep waters. Herein we describe Zygophylax kakaiba, sp. nov., collected in the Philippines at a depth of 580 m during the Siboga Expedition. Compared to its congeners, this species is distinguished by the abrupt curvature of the distal third of its hydrothecae towards the adcauline side.

  12. Green Fluorescence of Cytaeis Hydroids Living in Association with Nassarius Gastropods in the Red Sea.

    PubMed

    Prudkovsky, Andrey A; Ivanenko, Viatcheslav N; Nikitin, Mikhail A; Lukyanov, Konstantin A; Belousova, Anna; Reimer, James D; Berumen, Michael L

    2016-01-01

    Green Fluorescent Proteins (GFPs) have been reported from a wide diversity of medusae, but only a few observations of green fluorescence have been reported for hydroid colonies. In this study, we report on fluorescence displayed by hydroid polyps of the genus Cytaeis Eschscholtz, 1829 (Hydrozoa: Anthoathecata: Filifera) found at night time in the southern Red Sea (Saudi Arabia) living on shells of the gastropod Nassarius margaritifer (Dunker, 1847) (Neogastropoda: Buccinoidea: Nassariidae). We examined the fluorescence of these polyps and compare with previously reported data. Intensive green fluorescence with a spectral peak at 518 nm was detected in the hypostome of the Cytaeis polyps, unlike in previous reports that reported fluorescence either in the basal parts of polyps or in other locations on hydroid colonies. These results suggest that fluorescence may be widespread not only in medusae, but also in polyps, and also suggests that the patterns of fluorescence localization can vary in closely related species. The fluorescence of polyps may be potentially useful for field identification of cryptic species and study of geographical distributions of such hydroids and their hosts.

  13. Effects of initial surface wettability on biofilm formation and subsequent settlement of Hydroides elegans.

    PubMed

    Huggett, Megan J; Nedved, Brian T; Hadfield, Michael G

    2009-01-01

    Hydroides elegans is a major fouling organism in tropical waters around the world, including Pearl Harbor, Hawaii. To determine the importance of initial surface characteristics on biofilm community composition and subsequent colonization by larvae of H. elegans, the settlement and recruitment of larvae to biofilmed surfaces with six different initial surface wettabilities were tested in Pearl Harbor. Biofilm community composition, as determined by a combined approach of denaturing gradient gel electrophoresis and fluorescence in situ hybridization, was similar across all surfaces, regardless of initial wettability, and all surfaces had distinct temporal shifts in community structure over a 10 day period. Larvae settled and recruited in higher numbers to surfaces with medium to low wettability in both May and August, and also to slides with high wettability in August. Pearl Harbor biofilm communities developed similarly on a range of surface wettabilities, and after 10 days in Pearl Harbor all surfaces were equally attractive to larvae of Hydroides elegans, regardless of initial surface properties.

  14. Effects of oil pollution on hydroid behavior and neurophysiology. [Tubularic crocea; Myrionema hargitti

    SciTech Connect

    Michel, W.C.

    1985-01-01

    The hydroids, Tubularia crocea and Myrionema hargitti are sensitive organisms for assessing the effects of oil pollution. The abilities of these hydroids to capture Artemia nauplii were reduced after 1 hr exposure to a water-soluble fraction (WSF) of Monterey Formation crude oil. Algal symbionts within Myrionema contribute photosynthetically-fixed carbon to the host hydroid. No significant effects upon these symbionts were noted after 1 or 3 h but significant reductions in the mitotic index, photosynthesis and carbon translocation rates were observed after a 24-48 h exposure to 100% WSF. Myrionema hargitti was less responsive to mechanical stimuli after a brief 100% WSF exposure. The responsiveness to a feeding stimulant (proline) and concert frequency of 100% WSF-treated Tubularia crocea were lower than controls. Significant increases in epithelial activity were also recorded at 1% WSF and the increased firing frequency did not persist beyond the duration of the exposure. Bioaccumulation of /sup 3/H-toluene (20 ppm) from 100% WSF reached a maximum within 1 min but declined over the next hour. Higher concentrations of /sup 3/H-toluene evoked increased hydranth shedding with 1 h but these hydranths never accumulated as much /sup 3/H-toluene as hydranths exposed to lower concentrations.

  15. New additions to the shallow-water hydroids (Cnidaria: Hydrozoa) of the French Lesser Antilles: Martinique.

    PubMed

    Kim, Jeong-Kyu

    2013-01-01

    The present report provides the first general account of the shallow-water hydroids (excluding Eudendriidae) of Martinique, French Lesser Antilles. Of a total of 92 species recorded, 10 athecates and 31 thecates are discussed here, with the remaining species having been the subject of earlier accounts. Six hydroids, namely Halecium discoidum, H. xanthellatum, Sertularella calderi, Antennellapeculiaris, A. similis, and A. tubitheca, are new. Previously unreported data on the nematocyst complement of Heterocoryne caribbensis Wedler & Larson, 1986, Ectopleura mayeri Petersen, 1990, Ralpharia gorgoniae Petersen, 1990, and seven hebellid species are provided.'The gonotheca and the gonophore of Hebellopsis communis Calder, 1991 are described for the first time, allowing a genus transfer to Anthohebella Boero et al., 1997. Thyroscyphus longicaulis Splettstbsser, 1929, a species whose gonosome remained unknown until now, is redescribed based on new, fertile material of both sexes. The occurrence of Antennella quadriaurita Ritchie, 1909 in the Caribbean is questioned upon comparison of its cnidome with that of specimens from Tristan da Cunha, the type locality of this species. An unexpectedly wide morphological variation is noted for Aglaophenia rhynchocarpa Allman, 1877. Specimens corresponding to the Caribbean Gymnangium longicaudum (Nutting, 1900), are shown to be indistinguishable morphologically from a taxon described earlier from Brazil, Gymnangium allmani (Marktanner-Turneretscher, 1890), the latter having priority. Thorough descriptions are provided for the new, lesser known or unidentifiable species, while the common taxa are accompanied by brief remarks and/or distributional data. Illustrations are provided for each species discussed in order to justify their identification, and to facilitate identification by others. A checklist at the end of this work incorporates records of 101 species of hydroids reported from Martinique, both occurring in the present

  16. Assemblages of hydroids (Cnidaria) from three seamounts near Bermuda in the western North Atlantic

    NASA Astrophysics Data System (ADS)

    Calder, Dale R.

    2000-06-01

    Three seamounts flanking the oceanic island of Bermuda were sampled for hydroids. Collecting was undertaken by submersible (SDL-1) and by dredge at depths between 48 and 107 m on the summits of Argus and Challenger banks. A shallower collection (<20 m) from the pilings of a tower on Argus Bank was made using SCUBA. Major bottom types on both banks were aggregations of rhodoliths, limestone reefs, and areas of calcareous sand. Hydroids were ubiquitous, but quite sparse, on firm substrata. None was collected on sandy bottoms. Of 45 species identified from the two oceanic banks, over half (25) were found on both. On Bowditch Seamount, samples were obtained at depths between 1285 and 1381 m by dredge and grab. Of four species found, only one ( Filellum serratum) occurred in shallower collections from Argus and Challenger banks. Most species (43 of 48) from the three seamounts have been reported elsewhere in the Western Atlantic Tropical region, and many (38 of 48) are known from Bermuda. No endemics were discovered, and no relicts or exotics were recognized. Gonophores in >70% of the species are fixed sporosacs instead of free medusae. This conforms with a hypothesis that invertebrates of oceanic islands and seamounts tend to have short-lived pelagic larval stages, ensuring the greatest retention and conservation of propagules.

  17. Podocoryna martinicana, a new species of athecate hydroid (Cnidaria: Hydrozoa: Hydractiniidae) from the Caribbean.

    PubMed

    Galea, Horia R; Ferry, Romain

    2013-01-01

    A new species of hydroid, Podocoryna martinicana sp. nov., is described from the Lesser Antilles. It lives symbiotically with Iridopagurus caribbensis (A. Milne-Edwards & Bouvier, 1893) (Decapoda: Paguridae) inhabiting various gastropod shells. Its colonies are highly organized and develop exclusively around the aperture of the host shell. A few large, columnar gastrozooids provided with numerous tentacles arise from a perisarc-covered stolonal mat on the inner lip of the shell, and appear to form a gate when the hermit is withdrawn, while numerous, small, highly prolific gonozooids dress a line on the edge of the outer lip. Slender, very contractile tentaculozooids occur variably among the colonies. The dispersive stage, a free-swimming medusa with four well-developed marginal tentacles and no ocelli, is solely described based on young, sexually immature specimens. The species is further characterized by the peculiar bright white tinge of the core of both hydroid and medusa tentacles. Rich illustrations, data on the nematocyst complement, as well as comparisons with related congeners are provided.

  18. Occurrence and biogeography of hydroids (Cnidaria: Hydrozoa) from deep-water coral habitats off the southeastern United States

    NASA Astrophysics Data System (ADS)

    Henry, Lea-Anne; Nizinski, Martha S.; Ross, Steve W.

    2008-06-01

    Deep-water coral habitats off the southeastern USA (SEUS) support diverse fish and invertebrate assemblages, but are poorly explored. This study is the first to report on the hydroids collected from these habitats in this area. Thirty-five species, including two species that are likely new to science, were identified from samples collected primarily by manned submersible during 2001-2005 from deep-water coral habitats off North Carolina to east-central Florida. Eleven of the species had not been reported since the 19th to mid-20th century. Ten species, and one family, the Rosalindidae, are documented for the first time in the SEUS. Latitudinal ranges of 15 species are extended, and the deepest records in the western North Atlantic for 10 species are reported. A species accumulation curve illustrated that we continue to add to our knowledge of hydroid diversity in these habitats. Sexually mature individuals were collected for 19 species during the summer to early autumn months. Most of the observed species (89%) liberate planula larvae as part of their life cycles, suggesting that these species exhibit a reproductive strategy that reduces the risk of dispersal to sub-optimal habitats. Hydroids occurred across various substrata including coral rubble, live corals, rock and other animal hosts including hydroids themselves. All observed species were regionally widespread with typically deep-neritic to bathyal sub-tropical/tropical distributions. Hydroid assemblages from deep-water SEUS coral habitats were most similar to those from adjacent deep-water habitats off the SEUS (17 shared species), and those in the Straits of Florida/Bahamas and Caribbean/West Indian regions (14 and 8 shared species, respectively). The similarity to sub-tropical and tropical assemblages and the richness of plumularioids in the SEUS deep-water coral habitats support the idea of a Pleistocene intrusion of tropical species northwards following an intensification of the Gulf Stream from the

  19. Marine hydroid perisarc: a chitin- and melanin-reinforced composite with DOPA-iron(III) complexes.

    PubMed

    Hwang, Dong Soo; Masic, Admir; Prajatelistia, Ekavianty; Iordachescu, Mihaela; Waite, J Herbert

    2013-09-01

    Many marine invertebrates utilize biomacromolecules as building blocks to form their load-bearing tissues. These polymeric tissues are appealing for their unusual physical and mechanical properties, including high hardness and stiffness, toughness and low density. Here, a marine hydroid perisarc of Aglaophenia latirostris was investigated to understand how nature designs a stiff, tough and lightweight sheathing structure. Chitin, protein and a melanin-like pigment, were found to represent 10, 17 and 60 wt.% of the perisarc, respectively. Interestingly, similar to the adhesive and coating of marine mussel byssus, a DOPA (3,4-dihydroxyphenylalanine) containing protein and iron were detected in the perisarc. Resonance Raman microprobe analysis of perisarc indicates the presence of catechol-iron(III) complexes in situ, but it remains to be determined whether the DOPA-iron(III) interaction plays a cohesive role in holding the protein, chitin and melanin networks together.

  20. Mechanical robustness of the calcareous tubeworm Hydroides elegans: warming mitigates the adverse effects of ocean acidification.

    PubMed

    Li, Chaoyi; Meng, Yuan; He, Chong; Chan, Vera B S; Yao, Haimin; Thiyagarajan, V

    2016-01-01

    Development of antifouling strategies requires knowledge of how fouling organisms would respond to climate change associated environmental stressors. Here, a calcareous tube built by the tubeworm, Hydroides elegans, was used as an example to evaluate the individual and interactive effects of ocean acidification (OA), warming and reduced salinity on the mechanical properties of a tube. Tubeworms produce a mechanically weaker tube with less resistance to simulated predator attack under OA (pH 7.8). Warming (29°C) increased tube volume, tube mineral density and the tube's resistance to a simulated predatory attack. A weakening effect by OA did not make the removal of tubeworms easier except for the earliest stage, in which warming had the least effect. Reduced salinity (27 psu) did not affect tubes. This study showed that both mechanical analysis and computational modeling can be integrated with biofouling research to provide insights into how fouling communities might develop in future ocean conditions.

  1. Review of some little-known benthic hydroids (Cnidaria, Hydrozoa) from the Southern Ocean.

    PubMed

    Cantero, Álvaro L Peña

    2015-06-12

    A number of benthic hydroid species inhabiting the Southern Ocean are insufficiently characterized. A revision of eight little-known Antarctic species of the order Anthoathecata was made, based on the study of type material. Some of the species have not been recorded since their original description a century ago. Four species (Bimeria corynopsis, Bougainvillia macloviana, ?Koellikerina belgicae and Rhizorhagium antarcticum) belong to the family Bougainvilliidae, two species (Hydractinia angusta and H. dendritica) to the family Hydractiniidae, Perarella clavata to the family Cytaeididae and, finally, Rhysia halecii to the family Rhysiidae. For each species a list of synonyms, a description, a discussion on its relationship with other species and its systematic position, and an account of its autecological data are given. All records found in the literature have been checked.

  2. Calcification in the planula and polyp of the hydroid Hydractinia symbiolongicarpus (Cnidaria, Hydrozoa).

    PubMed

    Rogers, C L; Thomas, M B

    2001-08-01

    This study examines calcification in planulae and polyps of the hydroid Hydractinia symbiolongicarpus. We observed that established colonies produce a crystalline mat on their substratum and that crystals visible by polarized light microscopy occur in the vacuoles of the gastrodermal cells of both polyps and planulae. The crystalline mat was found by infrared spectroscopy to contain calcium carbonate in the form of aragonite. The composition of the vacuolar crystals and the cellular mechanisms for manufacturing them were explored by alteration of calcium levels in the environment and by the use of pharmacological agents (acetazolamide, caffeine, DIDS, diltiazem, nifedipine, procaine, Ruthenium Red, ryanodine and verapamil) that affect cellular uptake and transport of calcium and bicarbonate. The results indicated that the crystals in the vacuoles contained calcium carbonate. The gastrodermal cells are hypothesized to serve as a physiological sink for excess calcium that enters the organism during motility, secretion and metamorphosis of the planula, and to create a crystalline substratum for the colony of polyps.

  3. Some shallow-water hydroids (Cnidaria: Hydrozoa) from the central east coast of Florida, USA.

    PubMed

    Calder, Dale R

    2013-01-01

    This paper gives a systematic account of 67 species, referable to 22 families and 40 genera, identified in a small collection of hydroids from the central Atlantic coast of Florida between Melbourne and Palm Beach. The fauna mostly comprises an assemblage of tropical western Atlantic species ranging northwards along the southeastern coast of the United States. One new species, Lafoea intorta, is described. Applying Reversal of Precedence provisions in zoological nomenclature, the widely-used generic name Halopteris Allman, 1877 is designated as valid and as a nomen protectum, while its virtually unused senior synonym Halicornaria Hincks, 1865 (not Halicornaria Allman, 1874) is reduced to a nomen oblitum. The genus Pasya Stechow, 1922 is resurrected for the hydroid generally known as Dynamena quadridentata (Ellis & Solander, 1786). Laomedea tottoni Leloup, 1935 is shown to be a junior objective synonym of Clytia fragilis Congdon, 1907, which in turn is a junior subjective synonym of Clytia linearis (Thornely, 1900). Obelia oxydentata Stechow, 1914 is recognized as distinct from O. bidentata Clark, 1875. Hincksella brevitheca Galea, 2009, first described from Cuba, is reported for only the second time; records of the species are added here from Grand Cayman Island and the Caribbean coast of Panama as well as from the Atlantic coast of Florida. Also reported for the second time is Antennella incerta Galea, 2010, previ-ously known only from Guadeloupe in the Caribbean Sea. The true Halopteris diaphana (Heller, 1868), known from the Mediterranean Sea and from Brazil, is reported for the first time from the western North Atlantic. Earlier records of the species in the region are based on misidentifications of H. alternata (Nutting, 1900). Male gonothecae of Halecium calderi Galea, 2010 are reported and illustrated for the first time.

  4. Natural products and morphogenic activity of γ-Proteobacteria associated with the marine hydroid polyp Hydractinia echinata.

    PubMed

    Guo, Huijuan; Rischer, Maja; Sperfeld, Martin; Weigel, Christiane; Menzel, Klaus Dieter; Clardy, Jon; Beemelmanns, Christine

    2017-07-01

    Illumina 16S rRNA gene sequencing was used to profile the associated bacterial community of the marine hydroid Hydractinia echinata, a long-standing model system in developmental biology. 56 associated bacteria were isolated and evaluated for their antimicrobial activity. Three strains were selected for further in-depth chemical analysis leading to the identification of 17 natural products. Several γ-Proteobacteria were found to induce settlement of the motile larvae, but only six isolates induced the metamorphosis to the primary polyp stage within 24h. Our study paves the way to better understand how bacterial partners contribute to protection, homeostasis and propagation of the hydroid polyp. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. [Spectral diversity among the members of the family of Green Fluorescent Protein in hydroid jellyfish (Cnidaria, Hydrozoa)].

    PubMed

    Ianushevich, Iu G; Shagin, D A; Fradkov, A F; Shakhbazov, K S; Barsova, E V; Gurskaia, N G; Labas, Iu A; Matts, M V; Luk'ianov, k A; Lul'ianov, S A

    2005-01-01

    The cDNAs encoding the genes of new proteins homologous to the well-known Green Fluorescent Protein (GFP) from the hydroid jellyfish Aequorea victoria were cloned. Two green fluorescent proteins from one un-identified anthojellyfish, a yellow fluorescent protein from Phialidium sp., and a nonfluorescent chromoprotein from another unidentified anthojellyfish were characterized. Thus, a broad diversity of GFP-like proteins among the organisms of the class Hydrozoa in both spectral properties and primary structure was shown.

  6. Looking for long-term changes in hydroid assemblages (Cnidaria, Hydrozoa) in Alboran Sea (South-Western Mediterranean): a proposal of a monitoring point for the global warming

    NASA Astrophysics Data System (ADS)

    González-Duarte, Manuel María; Megina, Cesar; Piraino, Stefano

    2014-12-01

    In the last 20-30 years, the temperature of the Mediterranean Sea has increased and global warming is allowing the establishment of tropical-affinity species into more temperate zones. Sessile communities are particularly useful as a baseline for ecological monitoring; however, a lack of historical data series exists for sessile marine organisms without commercial interest. Hydroids are ubiquitous components of the benthic sessile fauna on rocky shores and have been used as bio-indicators of environmental conditions. In this study on the benthic hydroid assemblages of the Chafarinas Islands (Alboran Sea, South-Western Mediterranean), we characterized the hydroid assemblages, identified the bathymetric gradients, and compared them with a previous study carried out in 1991. Hydroid assemblages showed a significant difference both between year and among depths. Furthermore, eight species not present in 1991 were found, including two possible new species and the tropical and subtropical species Sertularia marginata. Due to its strategic position at the entrance of the Mediterranean and the existence of previous data on hydroid assemblages, the Chafarinas Islands are proposed as a possible monitoring point for entrance of Atlantic tropical species into the Mediterranean Sea.

  7. Invasive Marine and Estuarine Animals of Hawaii and Other Pacific Islands

    DTIC Science & Technology

    2005-08-01

    V E RI CN NY NJ jPA DE ]MD [VA Re n Protozoans 2 2 2 2 3 Sponges 1 2 1 1 1 2 Jellyfish 2 3 4 Anemones 1 2 1 2 3 Hydrozoans 2 1 2 Platyhelminths 1 1...Anemone ME MA VA Sagartia elegans Anemone MA Cordylophora caspia Hydrozoa ME Convoluta convoluta Platyhelminth ME Tubificoides heterochaetus

  8. Toxicity of heavy metals on embryogenesis and larvae of the marine sedentary polychaete Hydroides elegans.

    PubMed

    Gopalakrishnan, S; Thilagam, H; Raja, P V

    2007-02-01

    The toxicity of heavy metals to marine invertebrates has been widely investigated; however, the effects on marine sedentary polychaetes have largely been ignored. The toxicity of copper, aluminium, lead, nickel, and zinc on fertilization, embryogenesis, and larvae of Hydroides elegans was examined in laboratory acute-toxicity tests. Exposure to metal during fertilization or early developmental stages leads to fertilization block and arrested development, which resulted in morphologic abnormalities in embryo and larvae. Fertilization rate showed a drastic decrease at the highest metal concentration tested. Embryos of H. elegans showed a differential response to metals, and the responses were stage-specific. The different morphologic effects of heavy metals reflect differentiation of the early embryonic cells. For individual metals, the toxicity ranking for 24-hour trochophore larvae was Cu > Al > Pb > Ni > Zn, with EC(50) values of 0.122, 0.210, 0.231, 0.316, and 0.391 mg l(-1), respectively. Rate of larval development and embryogenesis were the most sensitive end points, although the latter is more advisable for routine assessment of seawater quality because of its greater simplicity. In addition to bivalves and sea urchins, polychaete embryos can provide biologic criteria for seawater quality taking into account the sensitivity of a polychaete and contributing to the detection of harmful chemicals with no marked effect on the species currently in use in seawater quality bioassays.

  9. Ultrastructure of the calcium-sequestering gastrodermal cell in the hydroid Hydractinia symbiolongicarpus (Cnidaria, Hydrozoa).

    PubMed

    Dandar-Roh, Alicia M; Rogers-Lowery, Constance L; Zellmann, Erhard; Thomas, Mary Beth

    2004-05-01

    Large, free-floating crystals of calcium carbonate occur in vacuoles of gastrodermal cells of the hydroid Hydractinia symbiolongicarpus. Here, morphological details about the process by which these cells accumulate and sequester calcium are provided by a cytochemical method designed to demonstrate calcium at the ultrastructural level. Electron-dense material presumably indicative of the presence of calcium was EGTA-sensitive and was shown by parallel electron energy loss spectroscopy (EELS) and energy spectroscopic imaging (ESI) to contain calcium. Calcium occurred in only one cell type, the endodermally derived gastrodermal cell. In these cells, the electron-dense material appeared first as a fine precipitate in the cytosol and nucleus and later as larger deposits and aggregates in the vacuole. During the life cycle, gastrodermal cells of the uninduced planula and the planula during metamorphic induction sequestered calcium. In primary polyps and polyps from established colonies, gastrodermal cells sequestered calcium, but the endodermal secretory cells did not. Our observations support the hypothesis that gastrodermal cells function as a physiological sink for calcium that enters the organism in conjunction with calcium-requiring processes such as motility, secretion, and metamorphosis. Copyright 2004 Wiley-Liss, Inc.

  10. Organochlorine and PBDE concentrations in relation to cytochrome P450 activity in livers of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia), in San Francisco Bay, California.

    PubMed

    Herring, Garth; Ackerman, Joshua T; Eagles-Smith, Collin A; Adelsbach, Terrence L; Melancon, Mark J; Stebbins, Katie R; Hoffman, David J

    2010-04-01

    We measured halogenated organic contaminants (HOCs) [polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichloro-diphenyl-trichloroethane (DDT)] and P450 [e.g., ethoxyresorufin-O-dealkylase (EROD)] stress in livers from Caspian tern (Hydroprogne caspia) adults and Forster's tern (Sterna forsteri) adults and chicks in San Francisco Bay (SFB). Penta BDEs and tetra PBDEs composed 46-66% of SigmaPBDE in terns. PCB homologues di, tri, penta, hexa, and hepta composed 93-95% of SigmaPCBs and p'p-DDE composed 82-98% of all SigmaDDTs. We found similar concentrations of SigmaPBDEs [mean micrograms per gram wet weight (ww) +/- standard error = 0.4 +/- 0.1], SigmaPCBs (5.9 +/- 1.6), and SigmaDDTs (0.6 +/- 0.1) among species, sexes, and regions. However, concentrations were higher in Forster's tern adults than chicks (SigmaPBDEs = 0.4 +/- 0.1 and 0.1 +/- 0.1; SigmaPCBs = 7.08 +/- 2.4 and 2.4 +/- 1.4; SigmaDDTs = 0.5 +/- 0.1 and 0.1 +/- 0.1; respectively), and there was a nonsignificant trend of elevated SigmaPBDEs and SigmaPCBs for adult Forster's terns in the Central South Bay and Lower South Bay portions of SFB. Combined Forster's tern and Caspian tern SigmaDDTs bioaccumulated similarly to selenium, but not mercury, and there was a nonsignificant but positive trend for SigmaPBDEs and SigmaPCBs bioaccumulation with mercury. P450 protein activity was higher in adult Forster's terns than Caspian terns, higher in Central South Bay than in Lower South Bay, and higher in adult Forster's terns than in chicks.

  11. Oxidative stress response of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia) to mercury and selenium bioaccumulation in liver, kidney, and brain

    USGS Publications Warehouse

    Hoffman, David J.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; Adelsbach, Terrence L.; Stebbins, Katherine R.

    2011-01-01

    Bioindicators of oxidative stress were examined in prebreeding and breeding adult and chick Forster's terns (Sterna forsteri) and in prebreeding adult Caspian terns (Hydroprogne caspia) in San Francisco Bay, California. Highest total mercury (THg) concentrations (mean±standard error;μg/g dry wt) in liver (17.7±1.7), kidney (20.5±1.9), and brain (3.0±0.3) occurred in breeding adult Forster's terns. The THg concentrations in liver were significantly correlated with hepatic depletion of reduced glutathione (GSH), increased oxidized glutathione (GSSG):GSH ratio, and decreased hepatic gamma-glutamyl transferase (GGT) activity in adults of both tern species. Prefledging Forster's tern chicks with one-fourth the hepatic THg concentration of breeding adults exhibited effects similar to adults. Total mercury-related renal GSSG increased in adults and chicks. In brains of prebreeding adults, THg was correlated with a small increase in glucose-6-phosphate dehydrogenase (G-6-PDH) activity, suggestive of a compensatory response. Brain THg concentrations were highest in breeding adult Forster's terns and brain tissue exhibited increased lipid peroxidation as thiobarbituric acid-reactive substances, loss of protein bound thiols (PBSH), and decreased activity of antioxidant enzymes, GSSG reductase (GSSGrd), and G-6-PDH. In brains of Forster's tern chicks there was a decrease in total reduced thiols and PBSH. Multiple indicator responses also pointed to greater oxidative stress in breeding Forster's terns relative to prebreeding terns, attributable to the physiological stress of reproduction. Some biondicators also were related to age and species, including thiol concentrations. Enzymes GGT, G-6-PDH, and GSSGred activities were related to species. Our results indicate that THg concentrations induced oxidative stress in terns, and suggest that histopathological, immunological, and behavioral effects may occur in terns as reported in other species.

  12. Oxidative stress response of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia) to mercury and selenium bioaccumulation in liver, kidney, and brain.

    PubMed

    Hoffman, David J; Eagles-Smith, Collin A; Ackerman, Joshua T; Adelsbach, Terrence L; Stebbins, Katherine R

    2011-04-01

    Bioindicators of oxidative stress were examined in prebreeding and breeding adult and chick Forster's terns (Sterna forsteri) and in prebreeding adult Caspian terns (Hydroprogne caspia) in San Francisco Bay, California. Highest total mercury (THg) concentrations (mean ± standard error; µg/g dry wt) in liver (17.7 ± 1.7), kidney (20.5 ± 1.9), and brain (3.0 ± 0.3) occurred in breeding adult Forster's terns. The THg concentrations in liver were significantly correlated with hepatic depletion of reduced glutathione (GSH), increased oxidized glutathione (GSSG):GSH ratio, and decreased hepatic gamma-glutamyl transferase (GGT) activity in adults of both tern species. Prefledging Forster's tern chicks with one-fourth the hepatic THg concentration of breeding adults exhibited effects similar to adults. Total mercury-related renal GSSG increased in adults and chicks. In brains of prebreeding adults, THg was correlated with a small increase in glucose-6-phosphate dehydrogenase (G-6-PDH) activity, suggestive of a compensatory response. Brain THg concentrations were highest in breeding adult Forster's terns and brain tissue exhibited increased lipid peroxidation as thiobarbituric acid-reactive substances, loss of protein bound thiols (PBSH), and decreased activity of antioxidant enzymes, GSSG reductase (GSSGrd), and G-6-PDH. In brains of Forster's tern chicks there was a decrease in total reduced thiols and PBSH. Multiple indicator responses also pointed to greater oxidative stress in breeding Forster's terns relative to prebreeding terns, attributable to the physiological stress of reproduction. Some biondicators also were related to age and species, including thiol concentrations. Enzymes GGT, G-6-PDH, and GSSGred activities were related to species. Our results indicate that THg concentrations induced oxidative stress in terns, and suggest that histopathological, immunological, and behavioral effects may occur in terns as reported in other species

  13. Oxidative stress response of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia) to mercury and selenium bioaccumulation in liver, kidney, and brain

    USGS Publications Warehouse

    Hoffman, David J.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; Adelsbach, Terrence L.; Stebbins, Katherine R.

    2011-01-01

    Bioindicators of oxidative stress were examined in prebreeding and breeding adult and chick Forster's terns (Sterna forsteri) and in prebreeding adult Caspian terns (Hydroprogne caspia) in San Francisco Bay, California. Highest total mercury (THg) concentrations (mean±standard error;μg/g dry wt) in liver (17.7±1.7), kidney (20.5±1.9), and brain (3.0±0.3) occurred in breeding adult Forster's terns. The THg concentrations in liver were significantly correlated with hepatic depletion of reduced glutathione (GSH), increased oxidized glutathione (GSSG):GSH ratio, and decreased hepatic gamma-glutamyl transferase (GGT) activity in adults of both tern species. Prefledging Forster's tern chicks with one-fourth the hepatic THg concentration of breeding adults exhibited effects similar to adults. Total mercury-related renal GSSG increased in adults and chicks. In brains of prebreeding adults, THg was correlated with a small increase in glucose-6-phosphate dehydrogenase (G-6-PDH) activity, suggestive of a compensatory response. Brain THg concentrations were highest in breeding adult Forster's terns and brain tissue exhibited increased lipid peroxidation as thiobarbituric acid-reactive substances, loss of protein bound thiols (PBSH), and decreased activity of antioxidant enzymes, GSSG reductase (GSSGrd), and G-6-PDH. In brains of Forster's tern chicks there was a decrease in total reduced thiols and PBSH. Multiple indicator responses also pointed to greater oxidative stress in breeding Forster's terns relative to prebreeding terns, attributable to the physiological stress of reproduction. Some biondicators also were related to age and species, including thiol concentrations. Enzymes GGT, G-6-PDH, and GSSGred activities were related to species. Our results indicate that THg concentrations induced oxidative stress in terns, and suggest that histopathological, immunological, and behavioral effects may occur in terns as reported in other species.

  14. Zyzzyzus rubusidaeus (Cnidaria, Hydrozoa, Tubulariidae), a new species of anthoathecate hydroid from the coast of British Columbia, Canada.

    PubMed

    Brinckmann-Voss, Anita; Calder, Dale R

    2013-01-01

    Zyzzyzus rubusidaeus, sp. nov., is described from inshore waters near the northern tip of Vancouver Island, British Columbia, Canada. Specimens were collected on rocky bottoms amongst barnacles, sponges, and compound ascidians at a depth of 18 m in Weynton Passage, Broughton Strait, during March, July, and October 2012. Polyps tend to grow in dense aggregations, often covering several square centimetres. Hydroids of Z. rubusidaeus most closely resemble those of Z. robustus Petersen, 1990 from Greenland, but differ in having aboral tentacles that are scattered in a narrow band around the base of the hydranth rather than occurring in a single whorl, thin and transparent instead of thick and stiff perisarc around hydrocaulus and tubers, and gonophores that arise from simple pedicels instead of short, stout branches. Possible embryos were present in female gonophores, although structures recognizable as actinula larvae have not been observed. The cnidome comprises small and large stenoteles, desmonemes, microbasic euryteles, basitrichs, and isorhizas. Polyps are a raspberry colour in life, a hue that has faded but little in our formalin-preserved material. Discovery of this hydroid brings the number of species currently recognized in genus Zyzzyzus Stechow, 1921 to seven.

  15. Harry Beal Torrey (1873-1970) of California, USA, and his research on hydroids and other coelenterates.

    PubMed

    Calder, Dale R

    2013-01-10

    Harry Beal Torrey was born on 22 May 1873 in Boston, Massachusetts. Two years later his family moved to Oakland, California. Torrey earned B.S. and M.S. degrees in zoology from the University of California, Berkeley, in 1895 and 1898 respectively, a Ph.D. in zoology from Columbia University in 1903, and an M.D. from the Medical College of Cornell University in 1927. He began his academic career as a marine biologist, investigating taxonomy, reproduction, morphology, development, regeneration, and behaviour of cnidarians of the west coast of the United States, but his research interests soon shifted to experimental biology and endocrinology. He eventually entered the field of medicine, specializing in public health, and served as a physician and hospital administrator. Torrey held academic positions at the University of California, Berkeley (1895-1912), the Marine Biological Association of San Diego (1903-1912), Reed College (1912-1920), the University of Oregon (1920-1926), and Stanford University (1928-1938). Following retirement from academia, he served as Director of the Children's Hospital of the East Bay, Oakland, California, from 1938 to 1942. In retirement, he continued an association with the University of California at Berkeley, near his home. Of 84 publications by him listed herein, 31 dealt with coelenterates. This paper focuses on his early research on coelenterate biology, and especially his contributions to taxonomy of hydroids. He was author or coauthor of six genera and 48 species-group taxa of Cnidaria, and he also described one new species each of Ctenophora and Phoronida. Although he abandoned systematic work early in his career, his most widely cited publication is a taxonomic monograph on hydroids of the west coast of North America, published in 1902. He died, at age 97, on 9 September 1970.

  16. Susceptibility to antibiotics of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host Aglaophenia octodonta (Cnidaria, Hydrozoa).

    PubMed

    Stabili, Loredana; Gravili, Cinzia; Boero, Ferdinando; Tredici, Salvatore M; Alifano, Pietro

    2010-04-01

    Vibrio harveyi is the major causal organism of vibriosis, causing potential devastation to diverse ranges of marine invertebrates over a wide geographical area. These microorganisms, however, are phenotypically diverse, and many of the isolates are also resistant to multiple antibiotics. In a previous study, we described a previously unknown association between Vibrio sp. AO1, a luminous bacterium related to the species V. harveyi, and the benthic hydrozoan Aglaophenia octodonta. In this study, we analyzed the susceptibility to antibiotics (ampicillin, streptomycin, tetracycline, or co-trimoxazole = mix of sulfamethoxazole and trimetoprim) of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host by using microcosm experiments. The results of minimum inhibitory concentration (MIC) experiments demonstrated that Vibrio sp. AO1 was highly resistant to ampicillin and streptomycin in pure culture. Nevertheless, these antibiotics, when used at sub-MIC values, significantly reduced the hydroid fluorescence. Co-trimoxazole showed the highest inhibitory effect on fluorescence of A. octodonta. However, in all treatments, the fluorescence was reduced after 48 h, but never disappeared completely around the folds along the hydrocaulus and at the base of the hydrothecae of A. octodonta when the antibiotic was used at concentration completely inhibiting growth in vitro. The apparent discrepancy between the MIC data and the fluorescence patterns may be due to either heterogeneity of the bacterial population in terms of antibiotic susceptibility or specific chemical-physical conditions of the hydroid microenvironment that may decrease the antibiotic susceptibility of the whole population. The latter hypothesis is supported by scanning electron microscope evidence for development of bacterial biofilm on the hydroid surface. On the basis of the results obtained, we infer that A. octodonta might behave as a reservoir of antibiotic multiresistant bacteria

  17. Deep-sea epibiotic hydroids from the abyssal plain adjacent to the Kuril-Kamchatka Trench with description of Garveia belyaevi sp. nov. (Hydrozoa, Bougainvilliidae)

    NASA Astrophysics Data System (ADS)

    Stepanjants, Sofia D.; Chernyshev, Alexey V.

    2015-01-01

    Examination of material collected by the German-Russian KuramBio Deep-Sea Expedition to the abyssal plain adjacent to the Kuril-Kamchatka Trench revealed about 17 hydroid species, including two species presumably new to science. Before the KuramBio Expedition only fragments of the unidentified hydroids and Cryptolaria sp. were collected in the Kuril-Kamchatka Trench from depths exceeding 3000 m. Descriptions of three species of epibiotic hydroids (including one new species, Garveia belyaevi sp. nov.) are presented herein. A colony of G. belyaevi sp. nov. (the third deep-sea and deepest species of the wide distributed genus Garveia) was attached to the spines of unidentified irregular sea urchins from depths 5217 to 5229 m. Нalitholus (?) sp. (Hydrozoa, Anthoathecata) colonized the skin of spoon worms (Echiura) but could not be identified to species level because the mature medusa stage was absent in the material. An unidentified juvenile polyp (Pandeidae) was found on the bryozoan Tricitella minini attached to spines of irregular sea urchins Echinosigra amphora. Colonial sedentary organisms inhabiting abyssal plains with soft bottoms may colonize invertebrates which are seldom used as substrates for epibiota in shallow waters. Epibiosis among abyssal colonial invertebrates, though extremely poorly studied, appears to be rather frequent.

  18. Adrenoceptor compounds prevent the settlement of marine invertebrate larvae: Balanus amphitrite (Cirripedia), Bugula neritina (Bryozoa) and Hydroides elegans (Polychaeta).

    PubMed

    Dahms, Hans-Uwe; Jin, Tao; Qian, Pei-Yuan

    2004-12-01

    The effects of the neurotransmitter blockers idazoxan and phentolamine on the larval settlement of three marine invertebrate species belonging to three different phyla were investigated by using in vitro concentration-response bioassays. Since neurotransmitters are known to influence metamorphic transitions in invertebrate larvae, neurotransmitter blockers were tested to evaluated their sublethal effects on larvae. The alpha-adrenergic antagonists idazoxan and phentolamine inhibited settlement of Balanus amphitrite (Cirripedia), Bugula neritina (Bryozoa) larvae, and larvae of the polychaete Hydroides elegans (Polychaeta) in a concentration-and taxon-dependent manner. At concentrations of 10(-3) M of both agents, larvae of all three species became immobile and subsequently died within 24 h. While cumulative settlement rates were observed after 48 h for B. amphitrite and H. elegans, and after 5 h for B. neritina, >90% of the larvae that settled did so within 24 h for the first two species and within 1 h for B. neritina. The tendency of the hydrophobic idazoxan and phentolamine to accumulate at solid surfaces most probably contributes to their successful inhibition of larval settlement. This ability makes them particularly attractive as candidates for the development of slow-release carriers in antifouling paints.

  19. Status of the names of some hydroid species (Cnidaria, Hydrozoa), described from the Atlantic coast of Patagonia.

    PubMed

    Miranda, Thaís P; Cunha, Amanda F; Marques, Antonio C

    2016-09-29

    Thirty new species of benthic leptothecate hydroids were described and named from Patagonia in a 1991 PhD dissertation by Mohamed El Beshbeeshy. Although constituting nomina nuda under provisions of the International Code of Zoological Nomenclature (ICZN), the names of some species were used in several scientific publications between 1991 and 2011. In 2011, the dissertation of El Beshbeeshy was published in accordance with Article 8 of the ICZN. Several species-group names appearing in that work nevertheless fail to fully comply with certain articles of the code. The goal of this contribution is to review the nomenclatural availability of the names of those 30 new taxa, and to clearly establish the current status of El Beshbeeshy's material. Two of them were made available in 1999 as part of studies other than those of El Beshbeeshy, and correct authorship and date is here noted. Twenty-one of the nomina nuda were made available in a work published by El Beshbeeshy in 2011, although some constitute junior synonyms. Six of the new species-group names appearing in both the 1991 and 2011 works, established following a literature review of Patagonian species, were proposed without re-description, or designation of name-bearing types, or locations of such types. Most of them do not meet criteria of availability and remain nomina nuda. The status of each is discussed to avoid additional nomenclatural errors and continued taxonomic confusion.

  20. Areas of endemism in the Southwestern Atlantic Ocean based on the distribution of benthic hydroids (Cnidaria: Hydrozoa).

    PubMed

    Miranda, Thaís Pires; Genzano, Gabriel Nestor; Marques, Antonio Carlos

    2015-10-27

    Geographic distributions of 130 species of benthic hydroids were used to infer areas of endemism in the Southwestern Atlantic Ocean (SWAO, between 22°S and 55°S). Endemicity Analysis (EA) was carried out with the software NDM VNDM, using a 2° x 2° grid with different values of F (F = 0.5 and F = 1.0) for inferred presence. Hypothesized areas of endemism (16 with F = 0.5 and 13 with F = 1.0) formed three generalized patterns: (1) Tropical, (2) Subtropical, and (3) disjunctions along Tropical and Subtropical areas. Areas of endemism estimated here were compared with provinces, ecoregions and areas of endemism previously defined (but not based on algorithmic analysis) in the literature. Ecological and historical aspects that are potentially relevant for the SWAO realm were contrasted, related and discussed to areas of endemism. This is the first study to apply NDM VNDM to the marine realm and one of the few that focuses on the SWAO.

  1. Evidence of compositional and ultrastructural shifts during the development of calcareous tubes in the biofouling tubeworm, Hydroides elegans.

    PubMed

    Chan, Vera Bin San; Vinn, Olev; Li, Chaoyi; Lu, Xingwen; Kudryavtsev, Anatoliy B; Schopf, J William; Shih, Kaimin; Zhang, Tong; Thiyagarajan, Vengatesen

    2015-03-01

    The serpulid tubeworm, Hydroides elegans, is an ecologically and economically important species whose biology has been fairly well studied, especially in the context of larval development and settlement on man-made objects (biofouling). Nevertheless, ontogenetic changes associated with calcareous tube composition and structures have not yet been studied. Here, the ultrastructure and composition of the calcareous tubes built by H. elegans was examined in the three early calcifying juvenile stages and in the adult using XRD, FTIR, ICP-OES, SEM and Raman spectroscopy. Ontogenetic shifts in carbonate mineralogy were observed, for example, juvenile tubes contained more amorphous calcium carbonate and were predominantly aragonitic whereas adult tubes were bimineralic with considerably more calcite. The mineral composition gradually shifted during the tube development as shown by a decrease in Sr/Ca and an increase of Mg/Ca ratios with the tubeworm's age. The inner tube layer contained calcite, whereas the outer layer contained aragonite. Similarly, the tube complexity in terms of ultrastructure was associated with development. The sequential appearance of unoriented ultrastructures followed by oriented ultrastructures may reflect the evolutionary history of serpulid tube biominerals. As aragonitic structures are more susceptible to dissolution under ocean acidification (OA) conditions but are more difficult to be removed by anti-fouling treatments, the early developmental stages of the tubeworms may be vulnerable to OA but act as the important target for biofouling control. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Bacterial community succession and chemical profiles of subtidal biofilms in relation to larval settlement of the polychaete Hydroides elegans.

    PubMed

    Chung, Hong Chun; Lee, On On; Huang, Yi-Li; Mok, Siu Yan; Kolter, Roberto; Qian, Pei-Yuan

    2010-06-01

    Earlier studies have shown that biofilms can mediate the larval settlement of the polychaete Hydroides elegans and that changes in the bacterial community structure and density of biofilms often alter the larval settlement response. However, the chemical cues that mediate this response remain unknown. In this study, both successional changes in the bacterial community structure and the chemical profiles of subtidal biofilms are described and related to the larval settlement response. Multispecies biofilms were developed on polystyrene Petri dishes and granite rock in the subtidal zone over a period of 20 days. The effects of the substratum and age on the bacterial community structure and chemical profiles of the biofilms were evaluated with two molecular methods (microarray (PhyloChip) and denaturing gradient gel electrophoresis) and with gas chromatography-mass spectrometry, respectively. Both age and substratum altered the bacterial community structures and chemical profiles of the biofilms. Age had a greater effect in shaping the bacterial community structure than did the substratum. In contrast, the type of substratum more strongly affected the chemical profile. Extracts of biofilms of different ages, which developed on different substrata, were tested for the settlement of H. elegans larvae. The extracts induced larval settlement in a biofilm-age-dependent manner, and extracts originating from different substrata of the same age showed no differences in larval settlement. Our results suggest that the larval settlement response cannot be predicted by the overall chemical composition of the biofilm alone.

  3. Additions to the hydroids (Cnidaria, Hydrozoa) of the Bay of Fundy, northeastern North America, with a checklist of species reported from the region.

    PubMed

    Calder, Dale R

    2017-04-24

    Two new species of hydroids, Eudendrium bleakneyi and Halecium praeparvum, are described from the Bay of Fundy. Fourteen others, Tubularia acadiae Petersen, 1990, Coryne pusilla Gaertner, 1774, Sarsia lovenii (M. Sars, 1846), Zanclea implexa (Alder, 1856), Corydendrium dispar Kramp, 1935, Rhizogeton fusiformis L. Agassiz, 1862, Bougainvillia muscus (Allman, 1863), Rhizorhagium roseum M. Sars, in G.O. Sars, 1874, Hydractinia symbiolongicarpus Buss & Yund, 1989, Eudendrium vaginatum Allman, 1863, Tiaropsis multicirrata (M. Sars, 1835), Obelia bidentata S.F. Clark, 1875, Halecium marsupiale Bergh, 1887, and Sertularella gigantea Hincks, 1874, are reported, with collection data, for the first time from the bay. All but Coryne pusilla, Rhizorhagium roseum, Eudendrium vaginatum, and Sertularella gigantea are also new to Atlantic Canada, while Zanclea implexa, Corydendrium dispar, and Halecium marsupiale are reported for the first time in the western North Atlantic. Two of those species, Hydractinia symbiolongicarpus and Obelia bidentata, are disjunct in distribution, with core populations occurring in warmer waters to the south of Cape Cod, Massachusetts. Both were discovered in Minas Basin, a hydrographically distinct embayment where surface water temperatures are much warmer during summer than in the perpetually cold lower Bay of Fundy. Rhizorhagium roseum and the subfamily Rhizorhagiinae are transferred from family Bougainvilliidae Lütken, 1850 to Pandeidae Haeckel, 1879. An annotated checklist of hydroids from the Fundy region, based on previously published reports and on new records of species, is added as an appendix. Included in the checklist are 43 species of anthoathecates and 75 species of leptothecates, referable to 30 families and 56 genera. Families with the most species were Sertulariidae (23), Haleciidae (13), Eudendriidae (11), and Obeliidae (10). Biogeographically, the aggregate hydroid fauna of the bay conforms with that occurring in other parts of the

  4. CO2-Driven Ocean Acidification Alters and Weakens Integrity of the Calcareous Tubes Produced by the Serpulid Tubeworm, Hydroides elegans

    PubMed Central

    Chan, Vera Bin San; Li, Chaoyi; Lane, Ackley Charles; Wang, Yanchun; Lu, Xingwen; Shih, Kaimin; Zhang, Tong; Thiyagarajan, Vengatesen

    2012-01-01

    As a consequence of anthropogenic CO2-driven ocean acidification (OA), coastal waters are becoming increasingly challenging for calcifiers due to reductions in saturation states of calcium carbonate (CaCO3) minerals. The response of calcification rate is one of the most frequently investigated symptoms of OA. However, OA may also result in poor quality calcareous products through impaired calcification processes despite there being no observed change in calcification rate. The mineralogy and ultrastructure of the calcareous products under OA conditions may be altered, resulting in changes to the mechanical properties of calcified structures. Here, the warm water biofouling tubeworm, Hydroides elegans, was reared from larva to early juvenile stage at the aragonite saturation state (ΩA) for the current pCO2 level (ambient) and those predicted for the years 2050, 2100 and 2300. Composition, ultrastructure and mechanical strength of the calcareous tubes produced by those early juvenile tubeworms were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and nanoindentation. Juvenile tubes were composed primarily of the highly soluble CaCO3 mineral form, aragonite. Tubes produced in seawater with aragonite saturation states near or below one had significantly higher proportions of the crystalline precursor, amorphous calcium carbonate (ACC) and the calcite/aragonite ratio dramatically increased. These alterations in tube mineralogy resulted in a holistic deterioration of the tube hardness and elasticity. Thus, in conditions where ΩA is near or below one, the aragonite-producing juvenile tubeworms may no longer be able to maintain the integrity of their calcification products, and may result in reduced survivorship due to the weakened tube protection. PMID:22912726

  5. Organochlorine and PBDE concentrations in relation to cytochrome P450 activity in livers of Forster’s Terns (Sterna forsteri) and Caspian Terns (Hydroprogne caspia), in San Francisco Bay, California

    USGS Publications Warehouse

    Herring, Garth; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Adelsbach, Terrence L.; Melancon, Mark J.; Stebbins, Katie R.; Hoffman, David J.

    2010-01-01

    We measured halogenated organic contaminants (HOCs) [polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichloro-diphenyl-trichloroethane (DDT)] and P450 [e.g., ethoxyresorufin-O-dealkylase (EROD)] stress in livers from Caspian tern (Hydroprogne caspia) adults and Forster’s tern (Sterna forsteri) adults and chicks in San Francisco Bay (SFB). Penta BDEs and tetra PBDEs composed 46–66% of ∑PBDE in terns. PCB homologues di, tri, penta, hexa, and hepta composed 93–95% of ∑PCBs and p′p-DDE composed 82–98% of all ∑DDTs. We found similar concentrations of ∑PBDEs [mean micrograms per gram wet weight (ww) ± standard error = 0.4 ± 0.1], ∑PCBs (5.9 ± 1.6), and ∑DDTs (0.6 ± 0.1) among species, sexes, and regions. However, concentrations were higher in Forster’s tern adults than chicks (∑PBDEs = 0.4 ± 0.1 and 0.1 ± 0.1; ∑PCBs = 7.08 ± 2.4 and 2.4 ± 1.4; ∑DDTs = 0.5 ± 0.1 and 0.1 ± 0.1; respectively), and there was a nonsignificant trend of elevated ∑PBDEs and ∑PCBs for adult Forster’s terns in the Central South Bay and Lower South Bay portions of SFB. Combined Forster’s tern and Caspian tern ∑DDTs bioaccumulated similarly to selenium, but not mercury, and there was a nonsignificant but positive trend for ∑PBDEs and ∑PCBs bioaccumulation with mercury. P450 protein activity was higher in adult Forster’s terns than Caspian terns, higher in Central South Bay than in Lower South Bay, and higher in adult Forster’s terns than in chicks.

  6. Photoacclimation and the effect of the symbiotic environment on the photosynthetic response of symbiotic dinoflagellates in the tropical marine hydroid Myrionema amboinense.

    PubMed

    Fitt; Cook

    2001-01-01

    Symbiotic dinoflagellates of the genus Symbiodinium and residing in the tropical hydroid Myrionema amboinense acclimate to low photon flux associated with low light 'shade' environments by increasing the amount of photosynthetic pigments per algal cell. The photosynthetic light intensity (PI) curves suggested that the low-light pigment response involved an increase in the number of photosynthetic units (PSU) in the chloroplast in addition to any increases in PSU size. Comparisons of light-dependent portion of the P-I curves of freshly isolated zooxanthellae (FIZ) with those from symbionts within the intact animal suggest that the host cell environment reduced average light levels reaching the symbiotic algae by more than half. This phenomenon may protect the algae from photobleaching of pigments and/or photoinhibition of photosynthesis at high light intensities present in shallow water habitats. In addition, maximum photosynthesis (P(max)) of symbionts removed from the host cell was higher than that recorded from dinoflagellates in the intact association, suggesting that the availability of carbon dioxide for photosynthesis may be limited in the intact hydroid. Shaded polyps contained fewer zooxanthellae and had less tissue biomass (measured as protein) than unshaded polyps. However symbionts from shaded polyps acclimated to the low light intensities by increasing chlorophyll levels and photosynthetic rates. The higher photosynthetic rates may have resulted from increased availability of carbon dioxide associated with lower symbiont density. Calculations of the contribution of zooxanthellae carbon to the host animal's respiratory demand (CZAR) showed that zooxanthellae from shaded polyps living in the field potentially provide about the same amount of carbon to their host as zooxanthellae from polyps living in the field in unshaded high light intensities.

  7. One new genus and three new species of plumulariid hydroids (Cnidaria, Hydrozoa, Plumulariidae) from the western Pacific Ocean, with a re-examination of Plumularia insignis Allman, 1883 and related taxa.

    PubMed

    Agís, José Ansín; Ramil, Fran; Calder, Dale R

    2016-09-19

    One new genus (Schizoplumularia) and three new species (Schizoplumularia vervoorti, S. geniculata and S. elegans) of plumulariids are recognized and described from large collections of plumularioid hydroids collected in New Caledonia and vicinity during several French expeditions. During taxonomic studies of these hydroids, colonies were compared with type material of Plumularia insignis Allman, 1883 and several other similar species-group taxa. As a result, three of the latter (P. flabellum Allman, 1883, P. conjuncta Billard, 1913, and P. billardi nom. nov.) are recognized as valid in addition to P. insignis. The binomen P. billardi is a replacement name for P. insignis var. gracilis Billard, 1913. In being elevated to the rank of species in this work, it becomes an invalid junior primary homonym of several others having the same name.

  8. Hydroids of the genus Sertularella (Cnidaria: Hydrozoa: Sertulariidae) from the Pacific coast of Canada in the collection of the Royal Ontario Museum, with descriptions of four new species.

    PubMed

    Choong, Henry H C

    2015-03-02

    Examination of the hydroid fauna of the Canadian Pacific coast in the collections of the Royal Ontario Museum collected between 1934 and 1985 indicates that the genus Sertularella Gray, 1848 from the infralittoral zone in the region remains poorly enumerated. The present study shows that several European or northeast Atlantic hydroid species, Sertularella conica Allman, 1877, Sertularella rugosa (Linnaeus, 1758), Sertularella tenella Alder, 1856, Sertularella polyzonias (Linnaeus, 1758), and Sertularella fusiformis (Hincks, 1861) have been incorrectly reported from the west coast of North America and suggests that assumptions of cosmopolitanism of some species require verification by continuing refinement of regional species-level taxonomy. Four new species, Sertularella cervicula, S. coronata, S. sacciformis, and S. pacifica are recognized and described in this paper. Sertularella gigantea Hincks, 1874 is recognized for the first time from the Pacific coast of North America.

  9. Deformities, PCBs, and TCDD-equivalents in double-crested cormorants (Phalacrocorax auritus) and Caspian terns (Hydroprogne caspia) of the Upper Great Lakes 1986–1991: Testing a cause-effect hypothesis

    USGS Publications Warehouse

    Ludwig, James P.; Kurita-Matsuba, Hiroko; Auman, Heidi J.; Ludwig, Matthew E.; Summer, Cheryl L.; Giesy, John P.; Tillitt, Donald E.; Jones, Paul D.

    1996-01-01

    Deformities have been reported in many species of colonial waterbirds from several localities on the Laurentian Great Lakes. The hypothesis that deformities were caused by either polychlorinated biphenyls (PCBs) or contaminants measured as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQs) is tested in this review of available data on concentrations of contaminants in eggs and observed deformities in embryos and chicks of double-crested cormorants (Phalacrocorax auritus) and Caspian terns (Hydroprogne caspia) between 1986 and 1991. Hatched chicks, live and dead eggs retrieved from 37 colonies in the upper Great Lakes were assessed for gross anatomical deformities. Rates of embryo death from seven regions of the upper Great Lakes were measured annually between 1986–1991. Half the embryos found dead in eggs were deformed. Nineteen types of abnormalities or deformities were observed. Subcutaneous edema in cormorants and gastroschisis in terns were the most common abnormalities in live or dead eggs. One of ten crossed-billed cormorant embryos survived to hatch. No bill-deformed terns hatched, although tern embryos had a greater rate of crossed-bills than cormorants. The suite of deformities and abnormalities found was similar to that produced in chickens by exposure to planar polychlorinated biphenyl (pPCB) and dioxin congeners. Hatching and deformity rates were correlated with concentrations ofpPCBs and TCDD-EQs. Planar PCB congeners that contributed most of the TCDD-EQs were present at concentrations sufficient to cause the observed effects. TCDD-EQs measured by H4IIE rat hepatoma cell 7-ethoxyresorufin O-deethylase (EROD) bioassay were highly correlated with deformity rates observed in cormorant chicks, live and dead eggs, and egg death rates. Similar correlations of TCDD-EQs with deformity rates were found in hatched tern chicks, dead eggs, and egg death rates, but not in live eggs. TCDD-EQs were more highly correlated to deformity and embryo death rates

  10. Aglaopheniid hydroids (Cnidaria: Hydrozoa: Aglaopheniidae) from bathyal waters of the Flemish Cap, Flemish Pass, and Grand Banks of Newfoundland (NW Atlantic) .

    PubMed

    Altuna, Alvaro; Murillo, Francisco J; Calder, Dale R

    2013-11-22

    Five species of aglaopheniid hydroids (Aglaophenopsis cornuta, Cladocarpus diana, C. formosus, C. integer, and Nematocarpus ramuliferus) were collected from the Flemish Cap, Flemish Pass, and Grand Banks of Newfoundland during surveys with bottom trawls, rock dredges, and scallop gear. All are infrequently reported species, with C. diana being discovered for the first time since its original description from Iceland. We document here the southernmost collections of C. diana and N. ramuliferus, both previously unknown in the western Atlantic. Each of the five species is described and illustrated based on fertile material, a key is provided for their identification, and bathymetric distributions are noted. Known depth ranges are extended for A. cornuta, C. diana, and C. integer. Aglaophenopsis and Nematocarpus are recognized as genera distinct from the polyphyletic Cladocarpus, based on the unique structure of the phylactocarp in the former, and the existence of appendages with nematothecae (ramuli) on almost all thecate internodes of hydrocladia in the latter. These appendages occur even in the absence of gonothecae, and are here considered defensive structures that protect the hydranths. In differing from typical phylactocarps, we accept the contention that they are characters of generic value.

  11. A parvicapsulid (Myxozoa) infecting Sprattus sprattus and Clupea harengus (Clupeidae) in the Northeast Atlantic uses Hydroides norvegicus (Serpulidae) as invertebrate host.

    PubMed

    Køie, Marianne; Karlsbakk, Egil; Einen, Ann-Cathrine Bårdsgjtere; Nylund, Are

    2013-05-01

    A myxosporean producing actinospores of the tetractinomyxon type in Hydroides norvegicus Gunnerus (Serpulidae) in Denmark was identified as a member of the family Parvicapsulidae based on small-subunit ribosomal DNA (SSU rDNA) sequences. Myxosporean samples from various Danish and Norwegian marine fishes were examined with primers that detect the novel myxosporean. Sprattus sprattus (Linnaeus) and Clupea harengus Linnaeus (Teleostei, Clupeidae) were found to be infected. The sequences of this parvicapsulid from these hosts were consistently slightly different (0.8% divergence), but both these genotypes were found in H. norvegicus. Disporic trophozoites and minute spores of a novel myxosporean type were observed in the renal tubules of some of the hosts found infected through PCR. The spores appear most similar to those of species of Gadimyxa Køie, Karlsbakk et Nylund, 2007, but are much smaller. The actinospores of the tetractinomyxon type from H. norvegicus have been described previously. In GenBank, the SSU rDNA sequences of Parvicapsulidae gen. sp. show highest identity (82%) with Parvicapsula minibicornis Kent, Whitaker et Dawe, 1997 infecting salmonids (Oncorhynchus spp.) in fresh water in the western North America. A phylogenetic analysis places P. minibicornis and Parvicapsulidae gen. sp. in a sister clade to the other parvicapsulids (Parvicapsula spp. and Gadimyxa spp.).

  12. Evaluation of Caspian tern (Hydroprogne caspia) and snowy plover (Charadrius alexandrinus nivosus) nesting on modified islands at the Don Edwards San Francisco Bay National Wildlife Refuge, California—2016 Annual Report

    USGS Publications Warehouse

    Hartman, C. Alex; Ackerman, Joshua T.; Herzog, Mark P.; Strong, Cheryl; Trachtenbarg, David; Shore, Crystal A.

    2017-05-08

    Executive SummaryIn order to address the 2008/10 and Supplemental 2014 NOAA Fisheries Biological Opinion for operation of the Federal Columbia River Power System, the U.S. Army Corps of Engineers (USACE) and the Bureau of Reclamation (Reclamation) developed and have begun implementation of Caspian tern (Hydroprogne caspia) management plans. This implementation includes redistribution of the Caspian terns in the Columbia River estuary and the mid-Columbia River region to reduce predation on salmonids listed under the Endangered Species Act. Key elements of the plans include (1) reducing nesting habitat for Caspian terns in the Columbia River estuary and the mid-Columbia River region, and (2) creating or modifying nesting habitat at alternative sites within the Caspian tern breeding range. USACE and Reclamation developed Caspian tern nesting habitat at the U.S. Fish and Wildlife Service Don Edwards San Francisco Bay National Wildlife Refuge (DENWR), California, prior to the 2015 nesting season. Furthermore, to reduce or eliminate potential conflicts between nesting Caspian terns and threatened western snowy plovers (Charadrius alexandrinus nivosus), nesting habitat for snowy plovers also was developed. Seven recently constructed islands within two managed ponds (Ponds A16 and SF2) of DENWR were modified to provide habitat attractive to nesting Caspian terns (5 islands) and snowy plovers (2 islands). These 7 islands were a subset of 46 islands recently constructed in Ponds A16 and SF2 to provide waterbird nesting habitat as part of the South Bay Salt Pond (SBSP) Restoration Project.We used social attraction methods (decoys and electronic call systems) to attract Caspian terns and snowy plovers to these seven modified islands, and conducted surveys between March and September of 2015 and 2016 to evaluate nest numbers, nest density, and productivity. Results from the 2015 nesting season, the first year of the study, indicated that island modifications and social

  13. Temperature dependent effects of elevated CO2 on shell composition and mechanical properties of Hydroides elegans: insights from a multiple stressor experiment.

    PubMed

    Chan, Vera B S; Thiyagarajan, Vengatesen; Lu, Xing Wen; Zhang, Tong; Shih, Kaimin

    2013-01-01

    The majority of marine benthic invertebrates protect themselves from predators by producing calcareous tubes or shells that have remarkable mechanical strength. An elevation of CO2 or a decrease in pH in the environment can reduce intracellular pH at the site of calcification and thus interfere with animal's ability to accrete CaCO3. In nature, decreased pH in combination with stressors associated with climate change may result in the animal producing severely damaged and mechanically weak tubes. This study investigated how the interaction of environmental drivers affects production of calcareous tubes by the serpulid tubeworm, Hydroides elegans. In a factorial manipulative experiment, we analyzed the effects of pH (8.1 and 7.8), salinity (34 and 27‰), and temperature (23°C and 29°C) on the biomineral composition, ultrastructure and mechanical properties of the tubes. At an elevated temperature of 29°C, the tube calcite/aragonite ratio and Mg/Ca ratio were both increased, the Sr/Ca ratio was decreased, and the amorphous CaCO3 content was reduced. Notably, at elevated temperature with decreased pH and reduced salinity, the constructed tubes had a more compact ultrastructure with enhanced hardness and elasticity compared to decreased pH at ambient temperature. Thus, elevated temperature rescued the decreased pH-induced tube impairments. This indicates that tubeworms are likely to thrive in early subtropical summer climate. In the context of climate change, tubeworms could be resilient to the projected near-future decreased pH or salinity as long as surface seawater temperature rise at least by 4°C.

  14. Temperature Dependent Effects of Elevated CO2 on Shell Composition and Mechanical Properties of Hydroides elegans: Insights from a Multiple Stressor Experiment

    PubMed Central

    Chan, Vera B. S.; Thiyagarajan, Vengatesen; Lu, Xing Wen; Zhang, Tong; Shih, Kaimin

    2013-01-01

    The majority of marine benthic invertebrates protect themselves from predators by producing calcareous tubes or shells that have remarkable mechanical strength. An elevation of CO2 or a decrease in pH in the environment can reduce intracellular pH at the site of calcification and thus interfere with animal’s ability to accrete CaCO3. In nature, decreased pH in combination with stressors associated with climate change may result in the animal producing severely damaged and mechanically weak tubes. This study investigated how the interaction of environmental drivers affects production of calcareous tubes by the serpulid tubeworm, Hydroides elegans. In a factorial manipulative experiment, we analyzed the effects of pH (8.1 and 7.8), salinity (34 and 27‰), and temperature (23°C and 29°C) on the biomineral composition, ultrastructure and mechanical properties of the tubes. At an elevated temperature of 29°C, the tube calcite/aragonite ratio and Mg/Ca ratio were both increased, the Sr/Ca ratio was decreased, and the amorphous CaCO3 content was reduced. Notably, at elevated temperature with decreased pH and reduced salinity, the constructed tubes had a more compact ultrastructure with enhanced hardness and elasticity compared to decreased pH at ambient temperature. Thus, elevated temperature rescued the decreased pH-induced tube impairments. This indicates that tubeworms are likely to thrive in early subtropical summer climate. In the context of climate change, tubeworms could be resilient to the projected near-future decreased pH or salinity as long as surface seawater temperature rise at least by 4°C. PMID:24265732

  15. Genetic analysis reveals multiple cryptic invasive species of the hydrozoan gene Cordylophora

    EPA Science Inventory

    Understanding the patterns and dynamics of biological invasions is a crucial prerequisite to predicting and mitigating their potential ecological and economic impacts. Unfortunately, in many cases such understanding is limited not only by ignorance of invasion history, but also b...

  16. Genetic analysis reveals multiple cryptic invasive species of the hydrozoan gene Cordylophora

    EPA Science Inventory

    Understanding the patterns and dynamics of biological invasions is a crucial prerequisite to predicting and mitigating their potential ecological and economic impacts. Unfortunately, in many cases such understanding is limited not only by ignorance of invasion history, but also b...

  17. Fish, fans and hydroids: host species of pygmy seahorses.

    PubMed

    Reijnen, Bastian T; van der Meij, Sancia E T; van Ofwegen, Leen P

    2011-01-01

    An overview of the octocoral and hydrozoan host species of pygmy seahorses is provided based on literature records and recently collected field data for Hippocampus bargibanti, Hippocampus denise and Hippocampus pontohi. Seven new associations are recognized and an overview of the so far documented host species is given. A detailed re-examination of octocoral type material and a review of the taxonomic history of the alcyonacean genera Annella (Subergorgiidae) and Muricella (Acanthogorgiidae) are included as baseline for future revisions. The host specificity and colour morphs of pygmy seahorses are discussed, as well as the reliability of (previous) identifications and conservation issues.

  18. Fish, fans and hydroids: host species of pygmy seahorses

    PubMed Central

    Reijnen, Bastian T.; van der Meij, Sancia E.T.; van Ofwegen, Leen P.

    2011-01-01

    Abstract An overview of the octocoral and hydrozoan host species of pygmy seahorses is provided based on literature records and recently collected field data for Hippocampus bargibanti, Hippocampus denise and Hippocampus pontohi. Seven new associations are recognized and an overview of the so far documented host species is given. A detailed re-examination of octocoral type material and a review of the taxonomic history of the alcyonacean genera Annella (Subergorgiidae) and Muricella (Acanthogorgiidae) are included as baseline for future revisions. The host specificity and colour morphs of pygmy seahorses are discussed, as well as the reliability of (previous) identifications and conservation issues. PMID:21747677

  19. Genetic analysis across differential spatial scales reveals multiple dispersal mechanisms for the invasive hydrozoan Cordylophora in the Great Lakes

    EPA Science Inventory

    Understanding patterns of post-establishment spread by invasive species is critically important for the design of effective management strategies and the development of appropriate theoretical models predicting spatial expansion of introduced populations. Here we explore genetic ...

  20. Genetic analysis across differential spatial scales reveals multiple dispersal mechanisms for the invasive hydrozoan Cordylophora in the Great Lakes

    EPA Science Inventory

    Understanding patterns of post-establishment spread by invasive species is critically important for the design of effective management strategies and the development of appropriate theoretical models predicting spatial expansion of introduced populations. Here we explore genetic ...

  1. Molecular Analysis of Tube Cement of the Biofouling Tubeworm Hydroides elegans

    DTIC Science & Technology

    2016-03-08

    determined the amino acid composition of them. The ratios of the amino acids in the tubes and cements are different from other marine cements. We used...next-gen. sequencing and determined that no marine -invert. cement homologs were found in the transcriptomes of the shell gland. We then used whole...uniquely expressed in and around the shell and may be components of the cement. Biofouling, marine adhesives, tubeworm recruitment U U U UU 6 Michael G

  2. Serotonin-immunoreactive neural system and contractile system in the hydroid Cladonema (Cnidaria, Hydrozoa).

    PubMed

    Mayorova, T D; Kosevich, I A

    2013-12-01

    Serotonin is a widespread neurotransmitter which is present in almost all animal phyla including lower metazoans such as Cnidaria. Serotonin detected in the polyps of several cnidarian species participates in the functioning of a neural system. It was suggested that serotonin coordinates polyp behavior. For example, serotonin may be involved in muscle contraction and/or cnidocyte discharge. However, the role of serotonin in cnidarians is not revealed completely yet. The aim of this study was to investigate the neural system of Cladonema radiatum polyps. We detected the net of serotonin-positive processes within the whole hydranth body using anti-serotonin antibodies. The hypostome and tentacles had denser neural net in comparison with the gastric region. Electron microscopy revealed muscle processes throughout the hydranth body. Neural processes with specific vesicles and neurotubules in their cytoplasm were also shown at an ultrastructural level. This work demonstrates the structure of serotonin-positive neural system and smooth muscle layer in C. radiatum hydranths.

  3. Post-embryonic larval development and metamorphosis of the hydroid Eudendrium racemosum (Cavolini) (Hydrozoa, Cnidaria)

    NASA Astrophysics Data System (ADS)

    Sommer, C.

    1990-09-01

    The morphology and histology of the planula larva of Eudendrium racemosum (Cavolini) and its metamorphosis into the primary polyp are described from light microscopic observations. The planula hatches as a differentiated gastrula. During the lecithotrophic larval period, large ectodermal mucous cells, embedded between epitheliomuscular cells, secrete a sticky slime. Two granulated cell types occur in the ectoderm that are interpreted as secretory and sensorynervous cells, but might also be representatives of only one cell type with a multiple function. The entoderm consists of yolk-storing gastrodermal cells, digestive gland cells, interstitial cells, cnidoblasts, and premature cnidocytes. The larva starts metamorphosis by affixing its blunt aboral pole to a substratum. While the planula flattens down, the mucous cells penetrate the mesolamella and migrate through the entoderm into the gastral cavity where they are lysed. Subsequently, interstitial cells, cnidoblasts, and premature cnidocytes migrate in the opposite direction, i.e. from entoderm to ectoderm. Then, the polypoid body organization, comprising head (hydranth), stem and foot, all covered by peridermal secretion, becomes recognisable. An oral constriction divides the hypostomal portion of the gastral cavity from the stomachic portion. Within the hypostomal entoderm, cells containing secretory granules differentiate. Following growth and the multiplication of tentacles, the head periderm disappears. A ring of gland cells differentiates at the hydranth's base. The positioning of cnidae in the tentacle ectoderm, penetration of the mouth opening and the multiplication of digestive gland cells enable the polyp to change from lecithotrophic to planktotrophic nutrition.

  4. Egg Size Effects across Multiple Life-History Stages in the Marine Annelid Hydroides diramphus

    PubMed Central

    Allen, Richard M.; Marshall, Dustin

    2014-01-01

    The optimal balance of reproductive effort between offspring size and number depends on the fitness of offspring size in a particular environment. The variable environments offspring experience, both among and within life-history stages, are likely to alter the offspring size/fitness relationship and favor different offspring sizes. Hence, the many environments experienced throughout complex life-histories present mothers with a significant challenge to optimally allocate their reproductive effort. In a marine annelid, we tested the relationship between egg size and performance across multiple life-history stages, including: fertilization, larval development, and post-metamorphosis survival and size in the field. We found evidence of conflicting effects of egg size on performance: larger eggs had higher fertilization under sperm-limited conditions, were slightly faster to develop pre-feeding, and were larger post-metamorphosis; however, smaller eggs had higher fertilization when sperm was abundant, and faster planktonic development; and egg size did not affect post-metamorphic survival. The results indicate that egg size effects are conflicting in H. diramphus depending on the environments within and among life-history stages. We suggest that offspring size in this species may be a compromise between the overall costs and benefits of egg sizes in each stage and that performance in any one stage is not maximized. PMID:25036850

  5. GEOGRAPHIC VARIATION IN BLOOD PLASMA PROTEIN CONCENTRATIONS IN YOUNG HERRING GULLS (LARUS ARGENTATUS) AND CASPIAN TERNS (STERNA CASPIA) FROM THE GREAT LAKES AND LAKE WINNIPEG. (R825216)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  6. Developing cDNA Libraries of Receptors Involved in the Recruitment of the Biofouling Tubeworm Hydroides elegans

    DTIC Science & Technology

    2014-06-12

    viruses, etc.). Thus, the riboprobes were designed targeting the innate immune receptors; Galactose Binding Lectin (GBL), Peptidoglycan Recognition...Control (C) Expression of Galactose Binding Lectin (D) Expression of Peptidoglycan Recognition Protein (E) Expression of NF-KappaB B. Differential

  7. Evaluation of Caspian tern (Hydroprogne caspia) and snowy plover (Charadrius alexandrinus nivosus) nesting on modified islands at the Don Edwards San Francisco Bay National Wildlife Refuge, California—2015 Annual Report

    USGS Publications Warehouse

    Hartman, C. Alex; Ackerman, Joshua T.; Herzog, Mark P.; Strong, Cheryl; Trachtenbarg, David; Sawyer, Kimberley A.; Shore, Crystal A.

    2016-03-24

    We used social attraction methods (decoys and electronic call systems) to attract Caspian terns and snowy plovers to these seven modified islands, and conducted surveys between March and September 2015 to evaluate nest numbers, nest density, and productivity. Results from the 2015 nesting season indicate that island modifications and social attraction measures were successful in establishing Caspian tern breeding colonies at Ponds A16 and SF2 of DENWR. Caspian terns nested on three of the five islands modified for Caspian terns (1 island in Pond A16 and 2 islands in Pond SF2). Caspian terns initiated at least 224 nests, fledged at least 174 chicks, and exhibited a breeding success rate of 0.78 fledged chicks/breeding pair. These results are promising considering it was the first year of the study and there was no prior history of Caspian terns nesting at Ponds A16 and SF2. In contrast, snowy plovers did not attempt to nest on any island in Ponds A16 and SF2. These results demonstrate the potential of social attraction measures to help establish tern nesting colonies in San Francisco Bay. Social attraction measures similar to those used in this study, but targeting other species such as Forster’s terns and American avocets, may help to establish waterbird breeding colonies at wetlands enhanced as part of the SBSP Restoration Project. 

  8. Macrofouling of deep-sea instrumentation after three years at 3690 m depth in the Charlie Gibbs fracture zone, mid-Atlantic ridge, with emphasis on hydroids (Cnidaria: Hydrozoa)

    NASA Astrophysics Data System (ADS)

    Blanco, R.; Shields, M. A.; Jamieson, A. J.

    2013-12-01

    Macrofouling is a common problem when deploying underwater instrumentation for long periods of time. It is a problem which can effect scientific experiments and monitoring missions though the creation of artificial reefs (thus increasing local biological activity) and reduce the quality of scientific data. Macrofouling is an issue typically considered to be restricted to the photic zones and is absent or negligible in the deep sea. To the contrary, the recovery of an accidentally lost deep-sea lander after 3 years submergence at 3960 m on the Mid-Atlantic Ridge (North Atlantic) revealed dense colonisation of macrofouling organisms. These organisms were found attached to all surfaces of the lander regardless of orientation and materials. The occurrence of such deep-sea macrofouling should be carefully investigated given the recent developments in long-term deep-sea observatory networks.

  9. Prefailure Evaluation Techniques for Marine Coatings

    DTIC Science & Technology

    1971-01-01

    mollusks, annelids, bryozoa , hydroids, etc) and soft (algae and scum). Besides the rating of fouling, the observer usually notes coating condition; with...mollusks, annelids, bryozoa , hydroids, etc) and soft (algae and scum). Besides the rating of fouling, the observer usually notes coating condition

  10. Biological Survey Along the St. Lawrence River for the St. Lawrence Seaway. Additional Locks and other Navigation Improvements Study.

    DTIC Science & Technology

    1979-01-01

    only one month (Table 6). Nine phylums were represented - Porifera, Coelenterata, Platyhelminthes , Nematoda, Nematomorpha, Firyozoa, Annel-ida...Hydroids) - colonies Phylum Platyhelminthes Class Turbellaria (Flatworms) Phylum Nematoda (Roundworms) Phylum Nematomorpha (Horsehair worms) Phylum

  11. 50 CFR 665.621 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Zoanthinaria. Hydrozoans, Bryzoans. sea squirts Tunicates. sea cucumbers and sea urchins Echinoderms. Those species not listed as CHCRT Mollusca. sea snails Gastropoda. Trochus. sea slugs Opistobranchs. black...) Crustaceans. Sponges Porifera. lace corals Stylasteridae. hydroid corals Solanderidae. segmented...

  12. 50 CFR 665.621 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Zoanthinaria. Hydrozoans, Bryzoans. sea squirts Tunicates. sea cucumbers and sea urchins Echinoderms. Those species not listed as CHCRT Mollusca. sea snails Gastropoda. Trochus. sea slugs Opistobranchs. black...) Crustaceans. Sponges Porifera. lace corals Stylasteridae. hydroid corals Solanderidae. segmented...

  13. 50 CFR 665.621 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Zoanthinaria. Hydrozoans, Bryzoans. sea squirts Tunicates. sea cucumbers and sea urchins Echinoderms. Those species not listed as CHCRT Mollusca. sea snails Gastropoda. Trochus. sea slugs Opistobranchs. black...) Crustaceans. Sponges Porifera. lace corals Stylasteridae. hydroid corals Solanderidae. segmented...

  14. 50 CFR 665.621 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Zoanthinaria. Hydrozoans, Bryzoans. sea squirts Tunicates. sea cucumbers and sea urchins Echinoderms. Those species not listed as CHCRT Mollusca. sea snails Gastropoda. Trochus. sea slugs Opistobranchs. black...) Crustaceans. Sponges Porifera. lace corals Stylasteridae. hydroid corals Solanderidae. segmented...

  15. The hydrozoan fauna (Cnidaria: Hydrozoa) from the peaks of the Ormonde and Gettysburg seamounts (Gorringe Bank, NE Atlantic).

    PubMed

    Moura, Carlos J

    2015-06-11

    Twenty-seven species of hydroids were collected from the peaks (35-42 meters depth) of the Gorringe Bank (NE Atlantic) during the oceanographic campaign 'LusoExpedição Olympus 2008'. Twenty-one of these species are new for the Gorringe Bank that now has published records for a total of 37 hydroid species. Lafoeina tenuis, Sertularella ellisii and Clytia hemisphaerica were the most abundant hydroid species collected. Results revealed spatial differences in the composition of species assemblages along the summits of the Gorringe, as only 14 of the species sampled were found both in the Ormonde and Gettysburg seamounts. The large density of algae at the peaks of the seamounts sustain a considerable hydrozoan diversity (23 species), but visibly inhibits the establishment of hydroids to the rocky substrates (only 2 species found). All the known hydrozoan species from the peaks of the Gorringe were exclusively collected during summer, thus sampling in other seasons may reveal further hydrozoan diversity due to seasonal patterns of growth of algae and hydroids. Nevertheless, the reasonably high levels of hydrozoan biodiversity demonstrated only from a small portion the summits of the Gorringe, corroborate its seamounts as 'biodiversity hotspots'. In agreement with previous investigations with shallow-water molluscs and sponges, the shallow-water hydroid fauna of the Gorringe revealed greater biogeographical affinities with the Mediterranean and mainland Portugal. This is the first report of Eudendrium armatum outside of the Mediterranean.

  16. Margelopsis gibbesii (McCrady, 1859) (Cnidaria, Hydrozoa): taxonomic review, and conservation of usage by designation of a lectotype.

    PubMed

    Calder, Dale R; Johnson, William S

    2015-12-02

    The binomen Nemopsis gibbesii McCrady, 1859, originally applied to a species of hydromedusa and its supposed hydroid from South Carolina, USA, has been known for more than a century to encompass two species. The medusa stage is conspecific with that of Nemopsis bachei L. Agassiz, 1849, while the hydroid stage is referable to the genus Margelopsis Hartlaub, 1897. Both that hydroid, and the medusa stage now subjectively linked to it, are commonly assigned to M. gibbesii. With no type having ever been designated for McCrady's species, a lectotype is designated to stabilize nomenclature of the species and serve as the standard for application of the name. In the absence of type specimens, an illustration of the hydroid of N. gibbesii by McCrady is chosen as lectotype, thereby conserving the name Margelopsis gibbesii in its accustomed usage. Hydroids and medusae of the species are re-described from new material, the cnidome of both stages is characterized, and a taxonomic review is given. The hydroid stage is reported for the first time since its original description in the mid-19th century. Medusae of M. gibbesii are also seen infrequently, having been reported only six times earlier.

  17. Ecological and morphological characteristics of Ephelota gemmipara (Ciliophora, Suctoria), epibiontic on Eudendrium racemosum (Cnidaria, Hydrozoa) from the Adriatic Sea.

    PubMed

    Tazioli, Silvia; Di Camillo, Cristina Gioia

    2013-11-01

    The relationship between the suctorian Ephelota gemmipara and the large hydroid Eudendrium racemosum from the North Adriatic Sea has been studied over its full annual cycle. Ephelota gemmipara settles on the perisarc of the hydroid, usually close to the hydranths in order to exploit the hydroid's food discharges. The life cycle of E. gemmipara is influenced by temperature variations and by its relationship with the host. The hydroid shows an active phase in the summer, and it gets through the adverse winter season forming resting stages. In April, when temperature increases, the hydroid starts its active phase and it is colonized by suctorians. From May to September the suctorians produce multiple buds (swarmers) that detach from the parental cells to settle on an Eudendrium colony. The abundance of the suctorian peaks in September, with more than 1.2 million ind. m(-2). Their proliferation coincides with the maximal abundance of their host and the highest water temperatures. On the contrary, sexual reproduction and the encystment occur when the temperature and the abundance of E. racemosum decrease. Lastly, we also report the presence of symbionts such as bacteria and the parasitic protozoans Tachyblaston ephelotensis and Enigmocoma acinetarum. Copyright © 2013 Elsevier GmbH. All rights reserved.

  18. The polyps of Oceania armata identified by DNA barcoding (Cnidaria, Hydrozoa).

    PubMed

    Schuchert, Peter

    2016-10-18

    The polyps of the widely distributed medusa Oceania armata have never been found in nature and only the primary polyp is known from breeding experiments. The fully developed colony is so far unknown. This report shows that DNA sequence data of the medusa stage of O. armata permits to identify several hydroid colonies from different geographic origins as the most likely polyp stage of this medusa. These hydroids had previously been misidentified as Turritopsis species, a closely related genus which also produces medusae resembling Oceania armata. It is concluded that most Turritopsis hydroids are not reliably identifiable to species level using morphological traits only. However, DNA barcodes, particularly 16S sequences, are an excellent tool to identify the species, although we still lack information on a few nominal species and the identities of some sequence-delimited clades need to be corroborated by the addition of topotype samples.

  19. DEEP-OCEAN BIODETERIORATION OF MATERIALS. PART VI. ONE YEAR AT 2,370 FEET.

    DTIC Science & Technology

    materials and all of the rope specimens were covered with bacterial slime . Cotton and manila ropes were severely deteriorated by marine microorganisms...environment without the aid of wood bait pieces. Hydroids and tubeworms were found on metal panels. Sea anemone, snails , and crabs were also found

  20. Cladocarpoides yucatanicus, a new genus and species of aglaopheniinae (coelenterata: hydroida: plumulariidae) from Arrowsmith Bank, Yucatan Channel

    SciTech Connect

    Bogle, M.A.

    1986-01-01

    Due to the unique character of its gonosome, a new genus and species of hydroid, Cladocarpoides yucatanicus (family Plumulariidae), is described and illustrated from material collected by the R/V Gerda and R/V John Elliott Pillsbury from the Yucatan Channel. It is compared with closely allied species of the genus Cladocarpus. 4 references, 3 figures.

  1. Extending the generality of ecological models to artificial floating habitats.

    PubMed

    Cole, Victoria J; Glasby, Tim M; Holloway, Michael G

    2005-08-01

    Marine assemblages on natural hard substrata are generally different from those on artificial habitats. There is, however, the potential for certain ecological processes to operate on both types of structures. On the sides of floating pontoons in Sydney Harbour, there were strong patterns of vertical distribution of sessile epibiotic organisms and molluscan grazers across relatively small spatial scales (in three defined zones, namely splash, shallow and deep). Patterns of vertical distribution of the tubeworms Hydroides spp. were reversed depending on the cover of mussels. A manipulative experiment was done to test if patterns of vertical distribution of Hydroides spp. were due to (1) the functioning of mussels or (2) the structure provided by mussels. Neither the functioning nor structure of mussels accounted for the patterns of distribution of Hydroides spp. Mussels increased recruitment of Hydroides spp., in the shallow and deep zones, and this was not due to increased surface area of the mussel shells. Manipulation of numbers of grazers and covers of sessile epibiota showed that the observed negative relationship between grazers and epibiota was due to grazers reducing recruitment of epibiota and epibiota decreasing survival of grazers. Most importantly, processes that accounted for patterns of distribution of mobile and sessile organisms on artificial floating structures were similar to those repeatedly shown to create such patterns on natural rocky shores.

  2. Annotated checklist of the false blister beetles (Coleoptera: Tenebrionoidea: Oedemeridae) from Iran.

    PubMed

    Ghahari, Hassan; Vázquez, Xavier A; Kubisz, Daniel

    2017-02-27

    A checklist of Oedemeridae species recorded from Iran is given. A total of 48 species and subspecies are reported, of which two, Nacerdochroa caspia (Faldermann, 1836) and Oedemera (Oedemera) virescens virescens (Linnaeus, 1767), are recorded here for the first time from Iran. A total of 18 species (37,5%) are Iranian endemics. The most common chorotypes are Turanian (16 species; 33%), Turano-European (8 species; 17%), SW-Asiatic chorotype (7 species; 15%), Sindian (6 species; 13%) and Arabo-sindian (4 species, 8%).

  3. [Procedure of running experiments on studying the effects of altered gas medium on culture of hydra Hydra attenuata].

    PubMed

    Ruzhichko, I R; Pavlov, B N

    2011-01-01

    Owing to the simple form and short gemmation, hydroid polyps have become a classic model object for studies into cell division and proliferation, and effects of changed environment on these processes. However, there is no procedure for studying of how altered gas composition of aqueous medium affects biological processes in hydroidpolyps. Testing of a procedure for objective studies with bioculture of Hydra attenuata resulted in determination of optimal hydra density in Petri dish. It was also stated that culture duplication takes minimal time at 25-30 degrees C. Tests verified efficiency of an incubator designed for experiment with Hydra attenuata in pressurized chambers enabling controlled ventilation by different gas mixtures. It was shown that time of culture duplication in normoxic and hypoxic nitrox is permanent and statistically different Therefore, the proposed procedure and incubator can be useful for fundamental and applied studies of the biological effects of altered gas medium on hydroid polyps.

  4. Allorecognition Triggers Autophagy and Subsequent Necrosis in the Cnidarian Hydractinia symbiolongicarpus

    PubMed Central

    Buss, Leo W.; Anderson, Christopher; Westerman, Erica; Kritzberger, Chad; Poudyal, Monita; Moreno, Maria A.; Lakkis, Fadi G.

    2012-01-01

    Transitory fusion is an allorecognition phenotype displayed by the colonial hydroid Hydractinia symbiolongicarpus when interacting colonies share some, but not all, loci within the allorecognition gene complex (ARC). The phenotype is characterized by an initial fusion followed by subsequent cell death resulting in separation of the two incompatible colonies. We here characterize this cell death process using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and continuous in vivo digital microscopy. These techniques reveal widespread autophagy and subsequent necrosis in both colony and grafted polyp assays. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays and ultrastructural observations revealed no evidence of apoptosis. Pharmacological inhibition of autophagy using 3-methyladenine (3-MA) completely suppressed transitory fusion in vivo in colony assays. Rapamycin did not have a significant effect in the same assays. These results establish the hydroid allorecognition system as a novel model for the study of cell death. PMID:23145018

  5. Deep-water Hydrozoa (Cnidaria: Medusozoa) in the Sea of Japan, collected during the 51st Cruise of R/V Akademik M.A. Lavrentyev, with description Opercularella angelikae, sp. nov.

    NASA Astrophysics Data System (ADS)

    Stepanjants, Sofia D.

    2013-02-01

    A report is given about Hydrozoa collected at depths between 455 and 3666 m in the Sea of Japan during the Russian-German expedition on R/V Akademik M.A. Lavrentyev. Ten species were found, with four of them being typical bathyal-abyssal and abyssal zones. A new species, Opercularella angelikae, is described, and it was the dominant hydroid in samples from 970 to 3660 m. Four eurybathic species characteristics of the Sea of Japan were sampled between 455 and 582 m. Abyssal (pseudoabyssal after Andriashev, 1979) hydroid fauna in the Sea of Japan is reported. The hypothesis that an exclusively deep-water fauna is lacking in abyssal regions of the Sea of Japan is disputed. The author's personal opinion considered concerning the borders of 1000 m between shallow and deep hydrozoan species in the Sea of Japan.

  6. Shallow-water Campanulariidae (Hydrozoa, Leptothecatae) from northern Bahía, Brazil.

    PubMed

    Kelmo, Francisco; Attrill, Martin J

    2003-03-01

    This study provides the first semi-quantititative account of the benthic campanulariid hydroids from Northern Bahia (Brazil), down to a depth of 60 m, based largely on collections obtained since 1992. Colonies were collected from six habitats along the coast of Salvador City, Todos os Santos Bay, Itaparica Island and at the northernmost part of the coast of the State of Bahia. From the 982 colonies examined, nine species were recorded: Campanularia hincksii, Clytia gracilis, C. hemisphaerica, C. hummelincki, C. linearis, C. macrotheca, C. noliformis, Obelia bidentata and O. dichotoma. Following a defined abundance scale, Clytia gracilis and C. noliformis were the most abundant species, whereas Campanularia hincksii and Clytia hummelincki were rare. Cluster analysis of relative abundance data revealed sandy shores had a markedly different hydroid community from other habitats. A simplified identification key, redescriptions, illustrations and data on nematocyst compliment are provided for each species. Campanularia hincksii, Clytia macrotheca and C. noliformis are reported from Brazil for the first time.

  7. Effect of parental hypoxic exposure on embryonic development of the offspring of two serpulid polychaetes: Implication for transgenerational epigenetic effect.

    PubMed

    Leung, J Y S; Cheung, S G; Qiu, J W; Ang, P O; Chiu, J M Y; Thiyagarajan, V; Shin, P K S

    2013-09-15

    Sperm production and motility, fecundity, and egg size, complexity and viability of serpulid polychaetes Hydroides elegans and Hydroides diramphus after 2-week treatment to hypoxia (2 mg O2 l(-1)) was compared with those under normoxia (6 mg O2 l(-1)). Despite reduced fecundity, the effect of parental hypoxic exposure on gamete quality was not discernible for both species. However, regardless of their subsequent dissolved oxygen environment, eggs spawned by H. elegans after hypoxic exposure were found to have lower fertilization success, slower embryonic development and a significantly higher yield of malformed embryos than those with a parental normoxic treatment. In contrast, neither fertilization success nor rate of embryonic development was affected for H. diramphus. The results implied that hypoxia was a potential stress reducing the recruitment of H. elegans through non-adaptive epigenetic effect, whereas H. diramphus was a more tolerant species to survive hypoxic events.

  8. A Guide to the Principal Marine Fouling Organisms, with Particular Reference to Cockburn Sound, W.A.,

    DTIC Science & Technology

    1982-07-01

    Western Australia Molluscs Algae Barnacles Sponges Bryozoa Hydroids Ascidians Tubeworms OSATI GROUPS 0603 ABSTRACT The principal types of marine fouling...Arthropoda, Class Crustacea) 13 7.1 General 13 7.2 Common Species 14 7.3 Other Species 15 7.4 References 15 8. BRYOZOANS (Phylum Bryozoa ) 15 8.1 General 15...Phylum Bryozoa ) 8.1 General Bryozoans grow as sedentary colonies in which a large number of individuals (zooids) are joined in various ways. They

  9. Preliminary Investigations of Biofouling of Ships’ Hulls: Non-Indigenous Species Investigations in the Columbia River

    DTIC Science & Technology

    2006-04-01

    Cutter Chlorophyta Chlorophyta spp P Cirrepedia Balanus amphitrite P/S Bivalvia Ostreidae sp A P/S Ischadium sp? S Bryozoa Watersipora...Balanus improvisus P/S Hydrozoa Unidentified hydroid B P/S Bryozoa Fredericella indica P Amphipoda Americorophium spp P/S Passenger Chlorophyta...Chlorophyta spp P Tanker Chlorophyta Chlorophyta spp P Cirrepedia Megabalanus sp P Bivalvia Ostreidae sp B P/S Mytilus sp A S Bryozoa

  10. Cnidocytes as Microscale Synthesis and Delivery Modules

    DTIC Science & Technology

    2008-05-31

    findings for nematocysts isolated from other species. Note that Physalia is not a true jellyfish , suggesting that the mechanisms behind discharge are not...also developed methods for culturing cells from jellyfish . The work began using Physalia, but has also used the sea nettle, Chrysaora, and the hydroid...also plated onto fragments of mesoglea, the “jelly” of the jellyfish , prepared in a variety of ways. This substrate has been used successfully by

  11. Life Cycle Evolution and Systematics of Campanulariid Hydrozoans

    DTIC Science & Technology

    2004-09-01

    Zealand H. gelatinosa, so this may either be under environmental control or indicative of cryptic speciation. Another gonophore variation is found in L...environment. In some Orthopyxis integra, whether or not medusoids are released is under environmental control ; however, the factors involved are unclear...179- 215. Stebbing ARD. 1981. The kinetics of growth control in a colonial hydroid. J Mar Biol Assoc UK 61(1): 35-63. Stebbing ARD. 1985. The use of

  12. Unmanned Maritime Systems Incremental Acquisition Approach

    DTIC Science & Technology

    2016-12-01

    aspect of the LDUUV is the departure from the standard acquisition process. According to Naval Drones (2015), in 2012 ONR awarded Hydroid, the maker...a variety of companies (Naval Drones , 2015). Naval Drones (2015) reported on the turbulent history of the LDUUV. In 2014, a Milestone A decision for...lead the design and fabrication of the LDUUV prototypes (Naval Drones , 2015). 9 H. ORGANIZATION OF THESIS After this introduction, chapter II

  13. Asymmetric total synthesis and stereochemical revision of gymnangiamide.

    PubMed

    Tone, Hitoshi; Buchotte, Marie; Mordant, Céline; Guittet, Eric; Ayad, Tahar; Ratovelomanana-Vidal, Virginie

    2009-05-07

    The asymmetric total synthesis of the originally proposed structure of gymnangiamide, a cytotoxic pentapeptide isolated from the marine hydroid Gymnangium regae Jaderholm, has been achieved. Key to the synthesis was the use of asymmetric hydrogenation of alpha-substituted beta-ketoesters through dynamic kinetic resolution for the preparation of nonproteinogenic chiral amino acids. The disparity of the NMR spectra between the synthetic material containing the L-serine residue and the natural product required a revision of the proposed structure.

  14. A sublittoral hard substrate epibenthic community below 30 m in head harbour passage, New Brunswick, Canada

    NASA Astrophysics Data System (ADS)

    Logan, Alan

    1988-10-01

    A sublittoral hard substrate epibenthic community has been photographically sampled mainly between depths of 30 and 140 m along two transects in Head Harbour Passage, Bay of Fundy, New Brunswick. A diverse biota of sponges, hydroids, anemones, polychaetes, brachiopods, molluscs, arthropods, echinoderms and tunicates is present throughout the depth range, but is dominated, in terms of abundance, by tubularian and campanularian hydroids, the anemone Tealia felina and the bivalve Modiolus modiolus. Cluster analysis revealed 5-6 clusters from each transect, separable on the basis of minor biological, as well as abundance, differences in the main taxa, within the depth range sampled. Abundance-depth data from each transect indicate an absence of encrusting coralline algae below 30 m and a gradual reduction in abundance of the sea urchin Strongylocentrotus droebachiensis and the brachiopod Terebratulina septentrionalis with increasing depth. In contrast, there is a gradual, but significant, increase in the abundance of tubularian hydroids, Tealia felina and Modiolus modiolus, with increasing depth. This community below about 30 m in Head Harbour Passage is here designated the Tubularia-Tealia felina-Modiolus modiolus community and forms part of the circalittoral subzone, sharing a gradational boundary with the overlying Terebratulina septentrionalis community.

  15. Mercury in birds of San Francisco Bay-Delta, California: trophic pathways, bioaccumulation, and ecotoxicological risk to avian reproduction

    USGS Publications Warehouse

    Ackerman, Joshua T.; Eagles-Smith, Collin A.; Heinz, Gary; De La Cruz, Susan E. W.; Takekawa, John Y.; Miles, A. Keith; Adelsbach, Terrence L.; Herzog, Mark P.; Bluso-Demers, Jill D.; Demers, Scott A.; Herring, Garth; Hoffman, David J.; Hartman, Christopher A.; Willacker, James J.; Suchanek, Thomas H.; Schwarzbach, Steven E.; Maurer, Thomas C.

    2014-01-01

    San Francisco Bay Estuary in northern California has a legacy of mercury contamination, which could reduce the health and reproductive success of waterbirds in the estuary. The goal of this study was to use an integrated field and laboratory approach to evaluate the risks of mercury exposure to birds in the estuary. We examined mercury bioaccumulation, and other contaminants of concern, in five waterbird species that depend heavily on San Francisco Bay Estuary for foraging and breeding habitat: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster’s terns (Sterna forsteri), Caspian terns (Hydroprogne caspia), and surf scoters (Melanitta perspicillata). These species have different foraging habitats and diets that represent three distinct foraging guilds within the estuary’s food web. In this report, we provide an integrated synthesis of the primary findings from this study and results are synthesized from 54 peer-reviewed publications generated to date with other unpublished results.

  16. Mercury correlations among six tissues for four waterbird species breeding in San Francisco Bay, California, USA

    USGS Publications Warehouse

    Eagles-Smith, Collin A.; Ackerman, Joshua T.; Adelsbach, T.L.; Takekawa, John Y.; Miles, A.K.; Keister, R.A.

    2008-01-01

    Despite a large body of research concerning mercury (Hg) in birds, no single tissue has been used consistently to assess Hg exposure, and this has hampered comparisons across studies. We evaluated the relationships of Hg concentrations among tissues in four species of waterbirds (American avocets [Recurvirostra americana], black-necked stilts [Himantopus mexicanus], Caspian terns [Hydroprogne caspia; formerly Sterna caspia], and Forster's terns [Sterna forsteri]) and across three life stages (prebreeding adults, breeding adults, and chicks) in San Francisco Bay, California, USA. Across species and life stages, Hg concentrations (least square mean ?? standard error) were highest in head feathers (6.45 ?? 0.31 ??g/g dry wt) and breast feathers (5.76 ?? 0.28 ??g/g dry wt), followed by kidney (4.54 ?? 0.22 ??g/g dry wt), liver (4.43 ?? 0.21 ??g/g dry wt), blood (3.10 ?? 0.15 ??g/g dry wt), and muscle (1.67 ?? 0.08 ??g/g dry wt). Relative Hg distribution among tissues, however, differed by species and life stage. Mercury concentrations were highly correlated among internal tissues (r 2 ??? 0.89). Conversely, the relationships between Hg in feathers and internal tissues were substantially weaker (r2 ??? 0.42). Regression slopes sometimes differed among species and life stages, indicating that care must be used when predicting Hg concentrations in one tissue based on those in another. However, we found good agreement between predictions made using a general tissue-prediction equation and more specific equations developed for each species and life stage. Finally, our results suggest that blood is an excellent, nonlethal predictor of Hg concentrations in internal tissues but that feathers are relatively poor indicators of Hg concentrations in internal tissues. ?? 2008 SETAC Printed in the USA.

  17. New records of sabellids and serpulids (Polychaeta: Sabellidae, Serpulidae) from the Tropical Eastern Pacific.

    PubMed

    Bastida-Zavala, J Rolando; Buelna, Alondra Sofía Rodríguez; DE León-González, Jesús Angel; Camacho-Cruz, Karla Andrea; Carmona, Isabel

    2016-11-07

    Sabellids and serpulids are two well represented families in the polychaete fauna of the Tropical Eastern Pacific, with 31 and 34 species respectively; however, most records come from the Gulf of California or the western coast of Baja California Peninsula. Only a few records are from localities in the large expanse of the central and southern Mexican Pacific. Thus, sabellids and serpulids were collected from several shallow water habitats along the coast of Mexican Pacific, such as coastal lagoons, coral reefs, rocky shores and from man-made structures as marinas, piers and ships of several harbors; additionally, specimens from national collections were revised. More than 8,400 specimens of sabellids and serpulids from the states of Baja California, Baja California Sur, Sonora, Sinaloa, Michoacán, Guerrero, Oaxaca and Chiapas, and some specimens from Panamá and Perú were examined. In the present work we record new localities of four sabellids and 24 serpulids. One sabellid, Branchiomma bairdi, is an exotic/invasive species in Oaxaca, Sinaloa and Baja California Sur, while four species of serpulids are exotic and/or cryptogenic species: Ficopomatus uschakovi, Hydroides dirampha, H. elegans and H. sanctaecrucis. Additionally, the geographical range has been extended for five species: the sabellids Pseudobranchiomma punctata from Oahu, Hawaii to La Paz Bay, and Parasabella pallida from California to Puerto Escondido, Baja California Sur; and for three serpulids, Hydroides inermis from the Galápagos Islands to Agua Blanca, Oaxaca, H. gairacensis from Panamá to Puerto Ángel, Oaxaca, and H. panamensis from Panamá to Huatulco, Oaxaca and Faro de Bucerías, Michoacán. Hydroides cf. amri, previously recorded as H. brachyacantha from Oahu, Hawaii, is more similar to H. amri from Australia. The number of sabellids recorded for the Tropical Eastern Pacific increased to 33, the serpulid species to 35.

  18. Biodiversity of prokaryotic communities associated with the ectoderm of Ectopleura crocea (Cnidaria, Hydrozoa).

    PubMed

    Di Camillo, Cristina Gioia; Luna, Gian Marco; Bo, Marzia; Giordano, Giuseppe; Corinaldesi, Cinzia; Bavestrello, Giorgio

    2012-01-01

    The surface of many marine organisms is colonized by complex communities of microbes, yet our understanding of the diversity and role of host-associated microbes is still limited. We investigated the association between Ectopleura crocea (a colonial hydroid distributed worldwide in temperate waters) and prokaryotic assemblages colonizing the hydranth surface. We used, for the first time on a marine hydroid, a combination of electron and epifluorescence microscopy and 16S rDNA tag pyrosequencing to investigate the associated prokaryotic diversity. Dense assemblages of prokaryotes were associated with the hydrant surface. Two microbial morphotypes were observed: one horseshoe-shaped and one fusiform, worm-like. These prokaryotes were observed on the hydrozoan epidermis, but not in the portions covered by the perisarcal exoskeleton, and their abundance was higher in March while decreased in late spring. Molecular analyses showed that assemblages were dominated by Bacteria rather than Archaea. Bacterial assemblages were highly diversified, with up to 113 genera and 570 Operational Taxonomic Units (OTUs), many of which were rare and contributed to <0.4%. The two most abundant OTUs, likely corresponding to the two morphotypes present on the epidermis, were distantly related to Comamonadaceae (genus Delftia) and to Flavobacteriaceae (genus Polaribacter). Epibiontic bacteria were found on E. crocea from different geographic areas but not in other hydroid species in the same areas, suggesting that the host-microbe association is species-specific. This is the first detailed report of bacteria living on the hydrozoan epidermis, and indeed the first study reporting bacteria associated with the epithelium of E. crocea. Our results provide a starting point for future studies aiming at clarifying the role of this peculiar hydrozoan-bacterial association.

  19. Biodiversity of Prokaryotic Communities Associated with the Ectoderm of Ectopleura crocea (Cnidaria, Hydrozoa)

    PubMed Central

    Di Camillo, Cristina Gioia; Luna, Gian Marco; Bo, Marzia; Giordano, Giuseppe; Corinaldesi, Cinzia; Bavestrello, Giorgio

    2012-01-01

    The surface of many marine organisms is colonized by complex communities of microbes, yet our understanding of the diversity and role of host-associated microbes is still limited. We investigated the association between Ectopleura crocea (a colonial hydroid distributed worldwide in temperate waters) and prokaryotic assemblages colonizing the hydranth surface. We used, for the first time on a marine hydroid, a combination of electron and epifluorescence microscopy and 16S rDNA tag pyrosequencing to investigate the associated prokaryotic diversity. Dense assemblages of prokaryotes were associated with the hydrant surface. Two microbial morphotypes were observed: one horseshoe-shaped and one fusiform, worm-like. These prokaryotes were observed on the hydrozoan epidermis, but not in the portions covered by the perisarcal exoskeleton, and their abundance was higher in March while decreased in late spring. Molecular analyses showed that assemblages were dominated by Bacteria rather than Archaea. Bacterial assemblages were highly diversified, with up to 113 genera and 570 Operational Taxonomic Units (OTUs), many of which were rare and contributed to <0.4%. The two most abundant OTUs, likely corresponding to the two morphotypes present on the epidermis, were distantly related to Comamonadaceae (genus Delftia) and to Flavobacteriaceae (genus Polaribacter). Epibiontic bacteria were found on E. crocea from different geographic areas but not in other hydroid species in the same areas, suggesting that the host-microbe association is species-specific. This is the first detailed report of bacteria living on the hydrozoan epidermis, and indeed the first study reporting bacteria associated with the epithelium of E. crocea. Our results provide a starting point for future studies aiming at clarifying the role of this peculiar hydrozoan-bacterial association. PMID:22768172

  20. Plastics on the Sargasso sea surface.

    PubMed

    Carpenter, E J; Smith, K L

    1972-03-17

    Plastic particles, in concentrations averaging 3500 pieces and 290 grams per square kilometer, are widespread in the western Sargasso Sea. Pieces are brittle, apparently due to the weathering of the plasticizers, and many are in a pellet shape about 0.25 to 0.5 centimeters in diameter. The particles are surfaces for the attachment of diatoms and hydroids. Increasing production of plastics, combined with present waste-disposal practices, will undoubtedly lead to increases in the concentration of these particles. Plastics could be a source of some of the polychlorinated biphenyls recently observed in oceanic organisms.

  1. Fouling and Boring of Glass Reinforced Plastic - Balsa Blocks in a Tropical Marine Environment,

    DTIC Science & Technology

    1983-03-01

    the wood and riddle a superficially sound structure [5,61. The zone of attack also varies as crustacean borers live mainly in the intertidal zone [71... substrate and any damage would be confined to outer layers. There was no sign of artsea attack in the foam-cored blocks examined after 19 months immersion...t 10.22 Barnacles 8.92 ± 5.65 Orgaric slime 8.92 t 4.38 Hydroids 5.00 ± 5.29I Erect bryozoans 3.42 t 7.52 Encrustinq bryozoan. 3.*25 ±+ 3.*39 Green

  2. Evolutionary crossroads in developmental biology: Cnidaria.

    PubMed

    Technau, Ulrich; Steele, Robert E

    2011-04-01

    There is growing interest in the use of cnidarians (corals, sea anemones, jellyfish and hydroids) to investigate the evolution of key aspects of animal development, such as the formation of the third germ layer (mesoderm), the nervous system and the generation of bilaterality. The recent sequencing of the Nematostella and Hydra genomes, and the establishment of methods for manipulating gene expression, have inspired new research efforts using cnidarians. Here, we present the main features of cnidarian models and their advantages for research, and summarize key recent findings using these models that have informed our understanding of the evolution of the developmental processes underlying metazoan body plan formation.

  3. Evolutionary crossroads in developmental biology: Cnidaria

    PubMed Central

    Technau, Ulrich; Steele, Robert E.

    2011-01-01

    There is growing interest in the use of cnidarians (corals, sea anemones, jellyfish and hydroids) to investigate the evolution of key aspects of animal development, such as the formation of the third germ layer (mesoderm), the nervous system and the generation of bilaterality. The recent sequencing of the Nematostella and Hydra genomes, and the establishment of methods for manipulating gene expression, have inspired new research efforts using cnidarians. Here, we present the main features of cnidarian models and their advantages for research, and summarize key recent findings using these models that have informed our understanding of the evolution of the developmental processes underlying metazoan body plan formation. PMID:21389047

  4. George James Allman (1812-1898): pioneer in research on Cnidaria and freshwater Bryozoa.

    PubMed

    Calder, Dale R

    2015-09-22

    George James Allman (1812-1898), acclaimed for pioneering studies of Hydrozoa and Bryozoa, was born in Cork, Ireland. He earned B.A. (1839) and M.B. (1843) degrees at Trinity College, Dublin, and an M.D. (1847) from Trinity College and Oxford University. Choosing academia over medicine, he served as Professor of Botany, University of Dublin (1844-1855), and as Regius Professor of Natural History, University of Edinburgh (1855-1870). Allman initially undertook research on freshwater bryozoans, but his interests later turned to marine hydroids. His bibliography, with publication dates retraced herein, comprises more than 200 titles. Most important of these were monographs on limnic Bryozoa (1857) and "gymnoblastic" or anthoathecate Hydrozoa (1871, 1872). Other prime works were on hydroids from the Straits of Florida (1877) and from the Challenger Expedition (1883, 1888). He named 22 families, 64 genera and 283 species of Hydrozoa, along with three families and nine species of Bryozoa. Of these, names of some five families, 19 genera, and 146 species of hydrozoans, along with three families and three species of bryozoans, are currently recognized as valid. For distinguished academic service, Allman was awarded the Royal Medal (Royal Society of London, 1873), the Brisbane Prize (Royal Society of Edinburgh, 1873), the Cunningham Medal (Royal Irish Academy, 1878), the Gold Medal (Linnean Society of London, 1896), and an LL.D. from the University of Edinburgh (1873). He died 24 November 1898 in Parkstone, Dorset, England. Two genera and 22 species have been named in his honour.

  5. The Reverend Thomas Hincks FRS (1818-1899): taxonomist of Bryozoa and Hydrozoa.

    PubMed

    Calder, Dale R

    2009-10-01

    Thomas Hincks was born 15 July 1818 in Exeter, England. He attended Manchester New College, York, from 1833 to 1839, and received a B.A. from the University of London in 1840. In 1839 he commenced a 30-year career as a cleric, and served with distinction at Unitarian chapels in Ireland and England. Meanwhile, he enthusiastically pursued interests in natural history. A breakdown in his health and permanent voice impairment during 1867-68 while at Mill Hill Chapel, Leeds, forced him reluctantly to resign from active ministry in 1869. He moved to Taunton and later to Clifton, and devoted much of the rest of his life to natural history. Hincks was elected a Fellow of the Royal Society of London in 1872 for noteworthy contributions to natural history. Foremost among his publications in science were "A history of the British hydroid zoophytes" (1868) and "A history of the British marine Polyzoa" (1880). Hincks named 24 families, 52 genera and 360 species and subspecies of invertebrates, mostly Bryozoa and Hydrozoa. Hincks died 25 January 1899 in Clifton, and was buried in Leeds. His important bryozoan and hydroid collections are in the Natural History Museum, London. At least six genera and 13 species of invertebrates are named in his honour.

  6. Epibiotic Vibrio luminous bacteria isolated from some hydrozoa and bryozoa species.

    PubMed

    Stabili, L; Gravili, C; Tredici, S M; Piraino, S; Talà, A; Boero, F; Alifano, P

    2008-11-01

    Luminous bacteria are isolated from both Hydrozoa and Bryozoa with chitinous structures on their surfaces. All the specimens of the examined hydroid species (Aglaophenia kirchenpaueri, Aglaophenia octodonta, Aglaophenia tubiformis, Halopteris diaphana, Plumularia setacea, Ventromma halecioides), observed under blue light excitation, showed a clear fluorescence on the external side of the perisarc (chitinous exoskeleton) around hydrocladia. In the bryozoan Myriapora truncata, luminous bacteria are present on the chitinous opercula. All the isolated luminous bacteria were identified on the basis of both phenotypic and genotypic analysis. The isolates from A. tubiformis and H. diaphana were unambiguously assigned to the species Vibrio fischeri. In contrast, the isolates from the other hydroids, phenotypically assigned to the species Vibrio harveyi, were then split into two distinct species by phylogenetic analysis of 16S rRNA gene sequences and DNA-DNA hybridization experiments. Scanning electron microscopy analysis and results of culture-based and culture-independent approaches enabled us to establish that luminous vibrios represent major constituents of the bacterial community inhabiting the A. octodonta surface suggesting that the interactions between luminous bacteria and the examined hydrozoan and bryozoan species are highly specific. These interactions might have epidemiological as well as ecological implications because of the opportunistic pathogenicity of luminous Vibrio species for marine organisms and the wide-distribution of the hydrozoan and bryozoan functioning as carriers.

  7. Allatotropin: An Ancestral Myotropic Neuropeptide Involved in Feeding

    PubMed Central

    Alzugaray, María Eugenia; Adami, Mariana Laura; Diambra, Luis Anibal; Hernandez-Martinez, Salvador; Damborenea, Cristina; Noriega, Fernando Gabriel; Ronderos, Jorge Rafael

    2013-01-01

    Background Cell-cell interactions are a basic principle for the organization of tissues and organs allowing them to perform integrated functions and to organize themselves spatially and temporally. Peptidic molecules secreted by neurons and epithelial cells play fundamental roles in cell-cell interactions, acting as local neuromodulators, neurohormones, as well as endocrine and paracrine messengers. Allatotropin (AT) is a neuropeptide originally described as a regulator of Juvenile Hormone synthesis, which plays multiple neural, endocrine and myoactive roles in insects and other organisms. Methods A combination of immunohistochemistry using AT-antibodies and AT-Qdot nanocrystal conjugates was used to identify immunoreactive nerve cells containing the peptide and epithelial-muscular cells targeted by AT in Hydra plagiodesmica. Physiological assays using AT and AT- antibodies revealed that while AT stimulated the extrusion of the hypostome in a dose-response fashion in starved hydroids, the activity of hypostome in hydroids challenged with food was blocked by treatments with different doses of AT-antibodies. Conclusions AT antibodies immunolabeled nerve cells in the stalk, pedal disc, tentacles and hypostome. AT-Qdot conjugates recognized epithelial-muscular cell in the same tissues, suggesting the existence of anatomical and functional relationships between these two cell populations. Physiological assays indicated that the AT-like peptide is facilitating food ingestion. Significance Immunochemical, physiological and bioinformatics evidence advocates that AT is an ancestral neuropeptide involved in myoregulatory activities associated with meal ingestion and digestion. PMID:24143240

  8. Mobile docking of REMUS-100 equipped with USBL-APS to an unmanned surface vehicle: A performance feasibility study

    NASA Astrophysics Data System (ADS)

    Miranda, Mario, II

    The overall objective of this work is to evaluate the ability of homing and docking an unmanned underwater vehicle (Hydroid REMUS 100 UUV) to a moving unmanned surface vehicle (Wave-Adaptive Modular Surface Vehicle USV) using a Hydroid Digital Ultra-Short Baseline (DUSBL) acoustic positioning system (APS), as a primary navigation source. An understanding of how the UUV can rendezvous with a stationary USV first is presented, then followed by a moving USV. Inherently, the DUSBL-APS is susceptible to error due to the physical phenomena of the underwater acoustic channel (e.g. ambient noise, attenuation and ray refraction). The development of an APS model has allowed the authors to forecast the UUV's position and the estimated track line of the USV as determined by the DUSBL acoustic sensor. In this model, focus is placed on three main elements: 1) the acoustic channel and sound ray refraction when propagating in an inhomogeneous medium; 2) the detection component of an ideal DUSBL-APS using the Neyman-Pearson criterion; 3) the signal-to-noise ratio (SNR) and receiver directivity impact on position estimation. The simulation tool is compared against actual open water homing results in terms of the estimated source position between the simulated and the actual USBL range and bearing information.

  9. Conducting tissues and phyletic relationships of bryophytes.

    PubMed Central

    Ligrone, R; Ducket, J G; Renzaglia, K S

    2000-01-01

    Internal specialized conducting tissues, if present, are restricted to the gametophytic generation in liverworts while they may occur in both generations in mosses. Conducting tissues are unknown in the anthocerotes. Water-conducting cells (WCCs) with walls perforated by plasmodesma-derived pores occur in the Calobryales and Pallaviciniaceae (Metzgeriales among liverworts and in Takakia among mosses. Imperforate WCCs (hydroids) are present in bryoid mosses. A polarized cytoplasmic organization and a distinctive axial system of microtubules is present in the highly specialized food-conducting cells of polytrichaceous mosses (leptoids) and in less specialized parenchyma cells of the leafy stem and seta in other mosses including Sphagnumn. A similar organization, suggested to reflect specialization in long-distance symplasmic transport of nutrients, also occurs in other parts of the plant in mosses, including rhizoids and caulonemata, and may be observed in thallus parenchyma cells of liverworts. Perforate WCCs in the Calobryales, Metzgeriales and Takakia, and hydroids in bryoid mosses, probably evolved independently Because of fundamental differences in developmental design, homology of any of these cells with tracheids is highly unlikely. Likewise, putative food-conducting of bryophytes present highly distinctive characteristics and cannot be considered homologous with the sieve cells of tracheophytes. PMID:10905610

  10. Multi-taxa coral reef community structure in relation to habitats in the Baa Atoll Man and Biosphere UNESCO Reserve (Maldives), and implications for its conservation

    NASA Astrophysics Data System (ADS)

    Jimenez, H.; Bigot, L.; Bourmaud, C.; Chabanet, P.; Gravier-Bonnet, N.; Hamel, M. A.; Payri, C.; Mattio, L.; Menou, J. L.; Naeem, S.; Rilwan, Y.; Sattar, S.; Scott, L.; Shiham, A.; Vigliola, L.; Andréfouët, S.

    2012-08-01

    The distribution of species in their environment is largely defined by habitat characteristics. Both species and habitat distributions can be used to define conservation areas, especially in highly diversified ecosystems like coral reefs where biodiversity inventories are lacking. The main objective of this study was to test the relationship between multi-taxa community structure (defined by richness, species lists, and taxonomic distinctness) and habitat typology in the Man and Biosphere UNESCO Reserve of Baa Atoll (Maldives). Species richness per taxon was described at 18 stations located on different habitats mapped using high resolution satellite imagery. A total of 1012 species were described including 178 macroalgae, 173 corals, 121 hydroids, 351 fish and 189 (other) macro-invertebrates. Rarity was extremely high for macro-invertebrates, algae and hydrozoans. The results highlighted a marked difference in species composition between stations for macro-algae and corals but not for other groups (hydroids, fish and macro-invertebrates). These distribution patterns were not strongly correlated to differences in habitat characteristics, which created a weak spatial structure of communities between habitats probably caused by differential exposure of atolls to monsoons and the 1998 bleaching event. Community differences between stations were often due to rarity. Therefore, identifying a network of protected areas that includes occurrences of all species may pose challenges. This is overcome by conservation planning scenarios using medium-size (of the order of 1 km2) management units.

  11. Trends in the Diversity, Distribution and Life History Strategy of Arctic Hydrozoa (Cnidaria)

    PubMed Central

    Ronowicz, Marta; Kukliński, Piotr; Mapstone, Gillian M.

    2015-01-01

    This is the first attempt to compile a comprehensive and updated species list for Hydrozoa in the Arctic, encompassing both hydroid and medusa stages and including Siphonophorae. We address the hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic by Hydrozoa after the Last Glacial Maximum. Presence-absence data of Hydrozoa in the Arctic were prepared on the basis of historical and present-day literature. The Arctic was divided into ecoregions. Species were grouped into distributional categories according to their worldwide occurrences. Each species was classified according to life history strategy. The similarity of species composition among regions was calculated with the Bray-Curtis index. Average and variation in taxonomic distinctness were used to measure diversity at the taxonomic level. A total of 268 species were recorded. Arctic-boreal species were the most common and dominated each studied region. Nineteen percent of species were restricted to the Arctic. There was a predominance of benthic species over holo- and meroplanktonic species. Arctic, Arctic-Boreal and Boreal species were mostly benthic, while widely distributed species more frequently possessed a pelagic stage. Our results support hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic. The predominance of benthic Hydrozoa suggests that the Arctic could have been colonised after the Last Glacial Maximum by hydroids rafting on floating substrata or recolonising from glacial refugia. PMID:25793294

  12. Barcoding Techniques Help Tracking the Evolutionary History of the Introduced Species Pennaria disticha (Hydrozoa, Cnidaria).

    PubMed

    Miglietta, Maria Pia; Odegard, Dean; Faure, Baptiste; Faucci, Anuschka

    2015-01-01

    The Christmas tree hydroid Pennaria disticha is listed as one of the most common introduced species in Hawaii. Firstly reported in Kaneohe Bay (Oahu) in 1928, it is now established throughout the entire archipelago, including the Northwestern Hawaiian Islands, a U.S. National Monument and World Heritage site. The Hawaiian population of P. disticha has also been reported as being the source of further introductions to Palmyra Atoll in the U.S. Line Islands. Using a phylogenetic hypothesis based on a 611 base pair fragment of the mitochondrial 16S barcoding gene, we demonstrate that P. disticha is a complex of cryptic species, rather than one species with cosmopolitan distribution. We also show that in Hawaii there are three species of Pennaria, rather than one introduced species. Two of these species share haplotypes with specimens from distant locations such as Florida and Panama and may have been introduced, possibly from the Atlantic Ocean. A third species could either represent a lineage with nearly cosmopolitan distribution, or another introduced species. Our dataset refutes the widely accepted idea that only one lineage of P. disticha is present in Hawaii. On the contrary, P. disticha in Hawaii may be the outcome of multiple independent introductions of several morphologically undistinguishable cryptic lineages. Our results uncover an unsuspected complexity within the very common hydroid P. disticha, and highlight the need for routine use of molecular tools, such as DNA barcoding, to improve the identification and recognition of non-indigenous species.

  13. ROLE OF THE GAMETE MEMBRANES IN FERTILIZATION IN SACCOGLOSSUS KOWALEVSKII (ENTEROPNEUSTA). I. THE ACROSOMAL REGION AND ITS CHANGES IN EARLY STAGES OF FERTILIZATION.

    PubMed

    COLWIN, A L; COLWIN, L H

    1963-12-01

    Previous electron microscope studies of sperm-egg association in the annelid Hydroides revealed novel aspects with respect to the acrosomal region. To determine whether these aspects were unique, a comparable study was made of a species belonging to a widely separated phylum, Hemichordata. Osmium tetroxide-fixed polyspermic material of the enteropneust, Saccoglossus, was used. The acrosomal region includes the membrane-bounded acrosome, with its large acrosomal granule and shallow adnuclear invagination, and the periacrosomal material which surrounds the acrosome except at the apex; here, the acrosomal membrane lies very close to the enclosing sperm plasma membrane. After reaching the egg envelope, the spermatozoon is activated and undergoes a series of changes: the apex dehisces and around the resulting orifice the acrosomal and sperm plasma membranes form a continuous mosaic membrane. The acrosomal granule disappears. Within 7 seconds the invagination becomes the acrosomal tubule, spans the egg envelopes, and meets the egg plasma membrane. The rest of the acrosomal vesicle everts. The periacrosomal mass changes profoundly: part becomes a fibrous core (possibly equivalent to a perforatorium); part remains as a peripheral ring. The basic pattern of structure and sperm-egg association in Saccoglossus is the same as in Hydroides. Previous evidence from four other phyla as interpreted here also indicates conformity to this pattern. The major role of the acrosome is apparently to deliver the sperm plasma membrane to the egg plasma membrane.

  14. Reaction of the mussel Mytilus galloprovincialis (Bivalvia) to Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria) concurrent infestation.

    PubMed

    Mladineo, Ivona; Petrić, Mirela; Hrabar, Jerko; Bočina, Ivana; Peharda, Melita

    2012-05-01

    In total 480 individuals of Mytilus galloprovincialis were sampled monthly from October 2009 to September 2010, at the shellfish farm in the Mali Ston Bay, south Adriatic Sea (Croatia) in order to assess the extent of pathology imposed by two parasites, Eugymnanthea inquilina (Cnidaria) and Urastoma cyprinae (Turbellaria). Although a deteriorating impact on host reproduction or condition index was lacking, we evidenced ultrastructural and functional alteration in host cells at the attachment site. Ultrastructural changes included hemocytic encapsulation of the turbellarian and cell desquamation in medusoid infestation. Caspase positive reaction inferred by immunohistochemistry (IHC) was triggered in cases of turbellarian infestation, in contrast with hydroids, suggesting that the former exhibits more complex host-parasite interaction, reflected in the persistent attempts of the parasite to survive bivalve reaction. We have evidenced that both organisms trigger specific host reaction that although not costly in terms of host reproductive cycle or growth, results in mild tissue destruction and hemocyte activation. A lower degree of tissue reaction was observed in cases of hydroid infestation, compared to turbellarian. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. The evolution of the immune-type gene family Rhamnospondin in cnidarians.

    PubMed

    López, Javier A; Fain, Matthew G; Cadavid, Luis F

    2011-03-01

    Rhamnose-binding lectins (RBLs) in vertebrates function in immunity as pattern recognition receptors, opsonization agents, and activators of pro-inflammatory cytokines. Although they have been identified in some invertebrate taxa, their distribution, function, and evolutionary patterns in basal metazoans, remain largely unknown. A unique RBL-containing protein composed of 8 thrombospondin type 1 repeats (TSRs) and a single RBL domain has been identified in the colonial hydroid Hydractinia symbiolongicarpus. This Rhamnospondin (Rsp) gene was specifically and constitutively expressed in the mouth of feeding polyps. Here we report the full characterization of a second Rsp gene from a H. symbiolongicarpus BAC library. Rsp1 and Rsp2 were 1.1kb apart, shared the same domain architecture and were 93% identical. Introns differed substantially in size and sequence, excepting two introns that were nearly identical, suggesting the action of inter-locus recombination. Sequencing full-length cDNAs from a wild-type individual corroborated the exon boundaries predicted from genomic DNA and showed gene polymorphism at both loci. Database searches and phylogenetic analyses showed that Rsp was found only in hydrozoans, indicating that it is an innovation of the cnidarian class Hydrozoa. Phylogenetic analysis of Rsp sequences in hydroids show a tendency of clustering paralogous genes, suggesting that they have evolved by concerted evolution. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Trends in the diversity, distribution and life history strategy of Arctic Hydrozoa (Cnidaria).

    PubMed

    Ronowicz, Marta; Kukliński, Piotr; Mapstone, Gillian M

    2015-01-01

    This is the first attempt to compile a comprehensive and updated species list for Hydrozoa in the Arctic, encompassing both hydroid and medusa stages and including Siphonophorae. We address the hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic by Hydrozoa after the Last Glacial Maximum. Presence-absence data of Hydrozoa in the Arctic were prepared on the basis of historical and present-day literature. The Arctic was divided into ecoregions. Species were grouped into distributional categories according to their worldwide occurrences. Each species was classified according to life history strategy. The similarity of species composition among regions was calculated with the Bray-Curtis index. Average and variation in taxonomic distinctness were used to measure diversity at the taxonomic level. A total of 268 species were recorded. Arctic-boreal species were the most common and dominated each studied region. Nineteen percent of species were restricted to the Arctic. There was a predominance of benthic species over holo- and meroplanktonic species. Arctic, Arctic-Boreal and Boreal species were mostly benthic, while widely distributed species more frequently possessed a pelagic stage. Our results support hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic. The predominance of benthic Hydrozoa suggests that the Arctic could have been colonised after the Last Glacial Maximum by hydroids rafting on floating substrata or recolonising from glacial refugia.

  17. Barcoding Techniques Help Tracking the Evolutionary History of the Introduced Species Pennaria disticha (Hydrozoa, Cnidaria)

    PubMed Central

    Miglietta, Maria Pia; Odegard, Dean; Faure, Baptiste; Faucci, Anuschka

    2015-01-01

    The Christmas tree hydroid Pennaria disticha is listed as one of the most common introduced species in Hawaii. Firstly reported in Kaneohe Bay (Oahu) in 1928, it is now established throughout the entire archipelago, including the Northwestern Hawaiian Islands, a U.S. National Monument and World Heritage site. The Hawaiian population of P. disticha has also been reported as being the source of further introductions to Palmyra Atoll in the U.S. Line Islands. Using a phylogenetic hypothesis based on a 611 base pair fragment of the mitochondrial 16S barcoding gene, we demonstrate that P. disticha is a complex of cryptic species, rather than one species with cosmopolitan distribution. We also show that in Hawaii there are three species of Pennaria, rather than one introduced species. Two of these species share haplotypes with specimens from distant locations such as Florida and Panama and may have been introduced, possibly from the Atlantic Ocean. A third species could either represent a lineage with nearly cosmopolitan distribution, or another introduced species. Our dataset refutes the widely accepted idea that only one lineage of P. disticha is present in Hawaii. On the contrary, P. disticha in Hawaii may be the outcome of multiple independent introductions of several morphologically undistinguishable cryptic lineages. Our results uncover an unsuspected complexity within the very common hydroid P. disticha, and highlight the need for routine use of molecular tools, such as DNA barcoding, to improve the identification and recognition of non-indigenous species. PMID:26657561

  18. Symbiotic association between Solanderia secunda (Cnidaria, Hydrozoa, Solanderiidae) and Medioantenna variopinta sp. nov. (Annelida, Polychaeta, Polynoidae) from North Sulawesi (Indonesia)

    NASA Astrophysics Data System (ADS)

    di Camillo, Cristina Gioia; Martin, Daniel; Britayev, Temir A.

    2011-12-01

    A mimic scale-worm was found associated with the athecate hydroid Solanderia secunda, commonly found on reefs of the NW coast of North Sulawesi, Indonesia. The species resembled Medioantenna clavata Imajima 1997, which was originally described without any reference to a symbiotic mode of life and later reported to be living on a solanderiid hydroid both in Japanese waters. A detailed morphological analysis led us to consider the Indonesian specimens as a new species, namely Medioantenna variopinta sp. nov., which is congeneric with the Japanese species. The new species differs from the type material of M. clavata as it has elytra with one prominent finger-like papilla and all neurochaetae with unidentate tip, instead of an elytral lump and both unidentate and bidentate neurochaetae on segment two. In turn, the Japanese worms associated with Solanderia are here referred to our new species. Two morphological features in M. variopinta sp. nov. are rather unusual among scale-worms. One of them is its extremely high level of bilateral asymmetry and antero-posterior variability in elytral distribution and the other one is its elongated, upwardly directed nephridial papillae. The morphology and geographical distribution of the host together with the known characteristics of the symbiotic association have also been highlighted.

  19. Transmission genetics of allorecognition in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa)

    SciTech Connect

    Mokady, O.; Buss, L.W.

    1996-06-01

    Allorecognition is ubiquitous, or nearly so, amongst colonial invertebrates. Despite the prominent role that such phenomena have played both in evolutionary theory and in speculations on the origin of the vertebrate immune system, unambiguous data on the transmission genetics of fusibility (i.e., the ability of two individuals to fuse upon tissue contact) is lacking for any metazoan outside of the phylum Chordata. We have developed lines of the hydroid Hydractinia symbiolongicarpus (Phylum Cnidaria) inbred for fusibility and here report results of breeding experiments establishing that fusibility segregates as expected for a single locus with codominantly expressed alleles, with one shared allele producing a fusible phenotype. Surveys of fusibility in field populations and additional breeding experiments indicate the presence of an extensive allele series. 21 refs., 1 fig., 3 tabs.

  20. Genome sequence of the pink–pigmented marine bacterium Loktanella hongkongensis type strain (UST950701–009PT), a representative of the Roseobacter group

    SciTech Connect

    Lau, Stanley CK; Riedel, Thomas; Fiebig, Anne; Han, James; Huntemann, Marcel; Petersen, Jörn; Ivanova, Natalia N.; Markowitz, Victor; Woyke, Tanja; Göker, Markus; Kyrpides, Nikos C.; Klenk, Hans-Peter; Qian, Pei-Yuan

    2015-08-11

    Loktanella hongkongensis UST950701-009PT is a Gram-negative, non-motile and rod-shaped bacterium isolated from a marine biofilm in the subtropical seawater of Hong Kong. When growing as a monospecies biofilm on polystyrene surfaces, this bacterium is able to induce larval settlement and metamorphosis of a ubiquitous polychaete tubeworm Hydroides elegans. The inductive cues are low-molecular weight compounds bound to the exopolymeric matrix of the bacterial cells. In the present study we describe the features of L. hongkongensis strain DSM 17492T together with its genome sequence and annotation and novel aspects of its phenotype. The 3,198,444 bp long genome sequence encodes 3104 protein-coding genes and 57 RNA genes. Lastly, the two unambiguously identified extrachromosomal replicons contain replication modules of the RepB and the Rhodobacteraceae-specific DnaA-like type, respectively.

  1. Genome sequence of the pink–pigmented marine bacterium Loktanella hongkongensis type strain (UST950701–009PT), a representative of the Roseobacter group

    DOE PAGES

    Lau, Stanley CK; Riedel, Thomas; Fiebig, Anne; ...

    2015-08-11

    Loktanella hongkongensis UST950701-009PT is a Gram-negative, non-motile and rod-shaped bacterium isolated from a marine biofilm in the subtropical seawater of Hong Kong. When growing as a monospecies biofilm on polystyrene surfaces, this bacterium is able to induce larval settlement and metamorphosis of a ubiquitous polychaete tubeworm Hydroides elegans. The inductive cues are low-molecular weight compounds bound to the exopolymeric matrix of the bacterial cells. In the present study we describe the features of L. hongkongensis strain DSM 17492T together with its genome sequence and annotation and novel aspects of its phenotype. The 3,198,444 bp long genome sequence encodes 3104 protein-codingmore » genes and 57 RNA genes. Lastly, the two unambiguously identified extrachromosomal replicons contain replication modules of the RepB and the Rhodobacteraceae-specific DnaA-like type, respectively.« less

  2. Serpulidae (Annelida) of Lizard Island, Great Barrier Reef, Australia.

    PubMed

    Kupriyanova, Elena K; Sun, Yanan; Hove, Harry A Ten; Wong, Eunice; Rouse, Greg W

    2015-09-18

    Serpulidae are obligatory sedentary polychaetes inhabiting calcareous tubes that are most common in subtropical and tropical areas of the world. This paper describes serpulid polychaetes collected from Lizard Island, Great Barrier Reef, Australia in 1983-2013 and deposited in Australian museums and overseas. In total, 17 serpulid genera were recorded, but although the study deals with 44 nominal taxa, the exact number of species remains unclear because a number of genera (i.e., Salmacina, Protula, Serpula, Spirobranchus, and Vermiliopsis) need world-wide revisions. Some species described herein are commonly found in the waters around Lizard Island, but had not previously been formally reported. A new species of Hydroides (H. lirs) and two new species of Semivermilia (S. annehoggettae and S. lylevaili) are described. A taxonomic key to all taxa found at Lizard Island is provided.

  3. Antifouling leaching technique for optical lenses

    USGS Publications Warehouse

    Strahle, William J.; Perez, C. L.; Martini, Marinna A.

    1994-01-01

    The effectiveness of optical lenses deployed in water less than 100 m deep is significantly reduced by biofouling caused by the settlement of macrofauna, such as barnacles, hydroids, and tunicates. However, machineable porous plastic rings can be used to dispense antifoulant into the water in front of the lens to retard macrofaunal growth without obstructing the light path. Unlike coatings which can degrade the optical performance, antifouling rings do not interfere with the instrument optics. The authors have designed plastic, reusable cup-like antifouling rings to slip over the optical lenses of a transmissometer. These rings have been used for several deployments on shallow moorings in Massachusetts Bay, MA and have increased the time before fouling degrades optical characteristics

  4. [Morphofunctional organization of reserve stem cells providing for asexual and sexual reproduction of invertebrates].

    PubMed

    Isaeva, V V; Akhmadieva, A V; Aleksandriova, Ia N; Shukaliuk, A I

    2009-01-01

    Published and original data indicating evolutionary conservation of the morphofunctional organization of reserve stem cells providing for asexual and sexual reproduction of invertebrates are reviewed. Stem cells were studied in representatives of five animal types: archeocytes in sponge Oscarella malakhovi (Porifera), large interstitial cells in colonial hydroid Obelia longissima (Cnidaria), neoblasts in an asexual race of planarian Girardia tigrina (Platyhelmintes), stem cells in colonial rhizocephalans Peltogasterella gracilis, Polyascus polygenea, and Thylacoplethus isaevae (Arthropoda), and colonial ascidian Botryllus tuberatus (Chordata). Stem cells in animals of such diverse taxa feature the presence of germinal granules, are positive for proliferating cell nuclear antigen, demonstrate alkaline phosphatase activity (at marker of embryonic stem cells and primary germ cells in vertebrates), and rhizocephalan stem cells express the vasa-like gene (such genes are expressed in germline cells of different metazoans). The self-renewing pool of stem cells is the cellular basis of the reproductive strategy including sexual and asexual reproduction.

  5. Learning through glass: the Blaschka marine models in North American post secondary education.

    PubMed

    Dyer, Ruthanna

    2008-03-01

    The use of the Blaschka marine models in North American educational institutions from 1870-1890 is detailed. Historical records of purchase from the Henry Augustus Ward papers and Leopold Blaschka's business notebooks and correspondence were examined to show how the models were received by curators and educators in North America, the significance of the models in marine biology education for secondary school teachers, and the role that Ward's Natural History Establishment played in the distribution of the models. A historical perspective of the business relationship between Henry Ward and Leopold Blaschka is presented. The taxa of the models ordered in North America are documented, as is the use of models demonstrating ontogeny of the organism. Educational practices of the period are explicated and the uses of the models to support contemporary biological concepts of the organism are elucidated through examination of Model 191a, a male colony of the hydroid, Tubularia.

  6. Transmission Genetics of Allorecognition in Hydractinia Symbiolongicarpus (Cnidaria: Hydrozoa)

    PubMed Central

    Mokady, O.; Buss, L. W.

    1996-01-01

    Allorecognition is ubiquitous, or nearly so, amongst colonial invertebrates. Despite the prominent role that such phenomena have played both in evolutionary theory and in speculations on the origin of the vertebrate immune system, unambiguous data on the transmission genetics of fusibility (i.e., the ability of two individuals to fuse upon tissue contact) is lacking for any metazoan outside of the phylum Chordata. We have developed lines of the hydroid Hydractinia symbiolongicarpus (Phylum Cnidaria) inbred for fusibility and here report results of breeding experiments establishing that fusibility segregates as expected for a single locus with codominantly expressed alleles, with one shared allele producing a fusible phenotype. Surveys of fusibility in field populations and additional breeding experiments indicate the presence of an extensive allele series. PMID:8725230

  7. Towards a revision of the genus Periclimenes: resurrection of Ancylocaris Schenkel, 1902, and designation of three new genera (Crustacea, Decapoda, Palaemonidae).

    PubMed

    Ďuriš, Zdeněk; Horká, Ivona

    2017-01-01

    Based on recently published molecular phylogenies of Indo-West Pacific palaemonid shrimps and further morphological evidence, the systematic position of several species of the polyphyletic genus Periclimenes is revised. The generic name Ancylocaris Schenkel, 1902 is re-established for the anemone-associated Periclimenes brevicarpalis. Actinimenesgen. n., is proposed for the anemone-associated Periclimenes inornatus, Periclimenes ornatellus and Periclimenes ornatus, all of which have a subspatulate first pereiopod. Cristimenesgen. n., is designated for the echinoderm-associated species, Periclimenes commensalis, Periclimenes cristimanus, and Periclimenes zanzibaricus, all with a unique carpo-propodal articulation of the second pereiopods. Rapimenesgen. n. is established for the hydroid and antipatharian-associated Periclimenes brucei, Periclimenes granulimanus, and Periclimenes laevimanus, for which the long, slender and unequal second pereiopods and prehensile ambulatory propodi are the main synapomorphic characters.

  8. A biomonitor as a measure of an ecologically-significant fraction of metals in an industrialized harbour.

    PubMed

    Gall, Mailie L; Poore, Alistair G B; Johnston, Emma L

    2012-03-01

    Biomonitors are commonly used to assess levels of bioavailable contaminants in the environment, however the relationships between biomonitor tissue concentrations and ecological effects are rarely assessed. The present study investigated metal contamination within a highly industrialised harbour and ecological effects on sessile invertebrates. The native oyster Saccostrea glomerata was deployed as a biomonitor across twenty-six sites to test for correlations between metal levels in their tissues and the recruitment of hard-substrate invertebrates. Concentrations of lead and copper in oyster tissues were negatively correlated with densities of the dominant barnacle, Amphibalanus variegatus, and positively correlated with densities of the dominant polychaete, Hydroides elegans, and the two native encrusting bryozoans Celloporaria nodulosa and Arachnopusia unicornis. Results suggest that highly localised events drive contaminant availability and that these events pose a significant risk to fauna. Biomonitoring studies may be enhanced by running concurrent ecological surveys.

  9. Towards a revision of the genus Periclimenes: resurrection of Ancylocaris Schenkel, 1902, and designation of three new genera (Crustacea, Decapoda, Palaemonidae)

    PubMed Central

    Ďuriš, Zdeněk; Horká, Ivona

    2017-01-01

    Abstract Based on recently published molecular phylogenies of Indo-West Pacific palaemonid shrimps and further morphological evidence, the systematic position of several species of the polyphyletic genus Periclimenes is revised. The generic name Ancylocaris Schenkel, 1902 is re-established for the anemone-associated Periclimenes brevicarpalis. Actinimenes gen. n., is proposed for the anemone-associated Periclimenes inornatus, Periclimenes ornatellus and Periclimenes ornatus, all of which have a subspatulate first pereiopod. Cristimenes gen. n., is designated for the echinoderm-associated species, Periclimenes commensalis, Periclimenes cristimanus, and Periclimenes zanzibaricus, all with a unique carpo-propodal articulation of the second pereiopods. Rapimenes gen. n. is established for the hydroid and antipatharian-associated Periclimenes brucei, Periclimenes granulimanus, and Periclimenes laevimanus, for which the long, slender and unequal second pereiopods and prehensile ambulatory propodi are the main synapomorphic characters. PMID:28228674

  10. Southern hemisphere deep-water stylasterid corals including a new species, Errinalabrosa sp. n. (Cnidaria, Hydrozoa, Stylasteridae), with notes on some symbiotic scalpellids (Cirripedia, Thoracica, Scalpellidae).

    PubMed

    Pica, Daniela; Cairns, Stephen D; Puce, Stefania; Newman, William A

    2015-01-01

    A number of stylasterid corals are known to act as host species and create refuges for a variety of mobile and sessile organisms, which enhances their habitat complexity. These include annelids, anthozoans, cirripeds, copepods, cyanobacteria, echinoderms, gastropods, hydroids and sponges. Here we report the first evidence of a diverse association between stylasterids and scalpellid pedunculate barnacles and describe a new stylasterid species, Errinalabrosa, from the Tristan da Cunha Archipelago. Overall, five stylasterid species are found to host eight scalpellid barnacles from several biogeographic regions in the southern hemisphere (Southern Ocean, temperate South America and the southern Indo-Pacific realms). There is an apparent lack of specificity in this kind of association and different grades of reaction to the symbiosis have been observed in the coral. These records suggest that the association between pedunculate barnacles and hard stylasterid corals has a wide distribution among different biogeographic realms and that it is relatively rare and confined largely to deep water.

  11. Evidence for a chemoautotrophically based food web at inactive hydrothermal vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    Erickson, K. L.; Macko, S. A.; Van Dover, C. L.

    2009-09-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where hydrothermally active and inactive sites are interspersed, hydroids, cladorhizid sponges, barnacles, bamboo corals, and other invertebrate types may occupy inactive sites. Carbon and nitrogen isotopic compositions of animals occupying inactive sites are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro-carnivorous invertebrates are the biomass dominants at inactive sites, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  12. Evidence for a Chemoautotrophically Based Food Web at Inactive Hydrothermal Vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    van Dover, C. L.; Erickson, K.; Macko, S.

    2008-12-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where active and inactive sulfide mounds are interspersed, hydroids, cladorhizid sponges, barnacles, and bamboo sponges, and other invertebrate types may occupy inactive sulfide mounds. Carbon and nitrogen isotopic compositions of animals occupying inactive sulfide mounds are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro- carnivorous invertebrates are the biomass dominants at inactive sulfide mounds, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  13. Total Synthesis of Solandelactone I.

    PubMed

    Eichenauer, Nils C; Tschersich, Roxanne; Pietruszka, Jörg

    2015-11-25

    Since the marine natural products solandelactones A-I were isolated from the hydroid Solanderia secunda and investigated by Seo et al. in 1996, considerable synthetic efforts toward these marine oxylipins followed. However, the structure elucidation of solandelactone I remained incomplete, and no synthesis has been reported. On the basis of our retrosynthetic analysis, the key building blocks were combined in a Horner-Wadsworth-Emmons reaction to create two common intermediates for the stereodivergent synthesis of all four diastereomers 1-4 matching the proposed structure of solandelactone I. Comparison of the published analytical data of natural product solandelactone I and data obtained from the synthetic endeavor toward diastereomers 1-4 enabled the structure assignment of isomer 3; the proposed biosynthetic pathway for marine oxylipins also supports the result.

  14. Severe Toxic Skin Reaction Caused by a Common Anemone and Identification of the Culprit Organism.

    PubMed

    Tezcan, Özgür Deniz; Gözer, Özgür

    2015-01-01

    In a marine envenomation, identification of the culprit organism can be difficult. In this case report, we present our method to identify snakelocks anemone (Anemonia viridis or formerly Anemonia sulcata) as the culprit of a severe toxic skin reaction. A. viridis is one of the most common anemones of the Mediterranean Sea and the North Atlantic Ocean. It lives at a depth of up to 10 m. It is a member of the phylum Cnidaria, which includes jellyfish, anemones, hydroids, and corals. They have toxic organelles called cnidocysts that have the capacity to inject venom with microscopic harpoon-like structures. The cnidocysts of A. viridis may cause toxic and allergic reactions, and although its venom is one of the most studied cnidarian venoms, detailed case reports are rare. © 2015 International Society of Travel Medicine.

  15. Effects of hypoxia on biofilms and subsequently larval settlement of benthic invertebrates.

    PubMed

    Cheung, S G; Chan, C Y S; Po, B H K; Li, A L; Leung, J Y S; Qiu, J W; Ang, P O; Thiyagarajan, V; Shin, P K S; Chiu, J M Y

    2014-08-30

    Biofilms on submerged surfaces are important in determining larval settlement of most marine benthic invertebrates. We investigated if exposure of biofilms to hypoxia would alter the larval settlement pattern and result in a shift in benthic invertebrate community structure in the field. Biofilms were first exposed to hypoxia or normoxia in laboratory microcosms for 7 days, and then deployed in the field for another 7 days to allow for larval settlement and recruitment to occur. Using terminal-restriction fragment length polymorphism of the 16S rRNA gene, this study showed that hypoxia altered the biofilm bacterial community composition, and the difference between the hypoxic and normoxic treatments increased with the time of exposure period. This study also demonstrated significantly different benthic invertebrate community structures as a result of biofilm exposure to hypoxia and that the hypoxic and normoxic treatments were dominated by Hydroides sp. and Folliculina sp., respectively.

  16. Genome sequence of the pink-pigmented marine bacterium Loktanella hongkongensis type strain (UST950701-009P(T)), a representative of the Roseobacter group.

    PubMed

    Lau, Stanley Ck; Riedel, Thomas; Fiebig, Anne; Han, James; Huntemann, Marcel; Petersen, Jörn; Ivanova, Natalia N; Markowitz, Victor; Woyke, Tanja; Göker, Markus; Kyrpides, Nikos C; Klenk, Hans-Peter; Qian, Pei-Yuan

    2015-01-01

    Loktanella hongkongensis UST950701-009P(T) is a Gram-negative, non-motile and rod-shaped bacterium isolated from a marine biofilm in the subtropical seawater of Hong Kong. When growing as a monospecies biofilm on polystyrene surfaces, this bacterium is able to induce larval settlement and metamorphosis of a ubiquitous polychaete tubeworm Hydroides elegans. The inductive cues are low-molecular weight compounds bound to the exopolymeric matrix of the bacterial cells. In the present study we describe the features of L. hongkongensis strain DSM 17492(T) together with its genome sequence and annotation and novel aspects of its phenotype. The 3,198,444 bp long genome sequence encodes 3104 protein-coding genes and 57 RNA genes. The two unambiguously identified extrachromosomal replicons contain replication modules of the RepB and the Rhodobacteraceae-specific DnaA-like type, respectively.

  17. Evolution of voltage-gated ion channels at the emergence of Metazoa.

    PubMed

    Moran, Yehu; Barzilai, Maya Gur; Liebeskind, Benjamin J; Zakon, Harold H

    2015-02-15

    Voltage-gated ion channels are large transmembrane proteins that enable the passage of ions through their pore across the cell membrane. These channels belong to one superfamily and carry pivotal roles such as the propagation of neuronal and muscular action potentials and the promotion of neurotransmitter secretion in synapses. In this review, we describe in detail the current state of knowledge regarding the evolution of these channels with a special emphasis on the metazoan lineage. We highlight the contribution of the genomic revolution to the understanding of ion channel evolution and for revealing that these channels appeared long before the appearance of the first animal. We also explain how the elucidation of channel selectivity properties and function in non-bilaterian animals such as cnidarians (sea anemones, corals, jellyfish and hydroids) can contribute to the study of channel evolution. Finally, we point to open questions and future directions in this field of research. © 2015. Published by The Company of Biologists Ltd.

  18. Feeding behaviour of a serpulid polychaete: Turning a nuisance species into a natural resource to counter algal blooms?

    PubMed

    Leung, Jonathan Y S; Cheung, Napo K M

    2017-02-15

    Occurrence of algal blooms in coastal waters is predicted to be more prevalent in future. To minimize their occurrence, manipulating the grazing pressure by suspension feeders is a potential management strategy, but its effectiveness may depend on their feeding preference. Therefore, we assessed the clearance rate of a widespread serpulid polychaete Hydroides elegans in larval and adult stages on various coastal phytoplankton. Additionally, the growth and development of H. elegans after consuming these phytoplankton were determined to reflect its sustainability to counter algal blooms. Results showed that H. elegans can consume and utilize different phytoplankton, except diatom Thalassiosira pseudonana, for growth and development in both life stages. Given the fast-colonizing ability which allows easy manipulation of abundance, H. elegans is considered practically and biologically ideal for tackling algal blooms. Other suspension feeders with different feeding niches could be used in combination to maximize the versatility of the top-down control.

  19. Southern hemisphere deep-water stylasterid corals including a new species, Errina labrosa sp. n. (Cnidaria, Hydrozoa, Stylasteridae), with notes on some symbiotic scalpellids (Cirripedia, Thoracica, Scalpellidae)

    PubMed Central

    Pica, Daniela; Cairns, Stephen D.; Puce, Stefania; Newman, William A.

    2015-01-01

    Abstract A number of stylasterid corals are known to act as host species and create refuges for a variety of mobile and sessile organisms, which enhances their habitat complexity. These include annelids, anthozoans, cirripeds, copepods, cyanobacteria, echinoderms, gastropods, hydroids and sponges. Here we report the first evidence of a diverse association between stylasterids and scalpellid pedunculate barnacles and describe a new stylasterid species, Errina labrosa, from the Tristan da Cunha Archipelago. Overall, five stylasterid species are found to host eight scalpellid barnacles from several biogeographic regions in the southern hemisphere (Southern Ocean, temperate South America and the southern Indo-Pacific realms). There is an apparent lack of specificity in this kind of association and different grades of reaction to the symbiosis have been observed in the coral. These records suggest that the association between pedunculate barnacles and hard stylasterid corals has a wide distribution among different biogeographic realms and that it is relatively rare and confined largely to deep water. PMID:25632246

  20. Aquaculture and urban marine structures facilitate native and non-indigenous species transfer through generation and accumulation of marine debris.

    PubMed

    Campbell, Marnie L; King, Staci; Heppenstall, Lara D; van Gool, Ella; Martin, Ross; Hewitt, Chad L

    2017-08-19

    Both the invasion of non-indigenous marine species (NIMS) and the generation and accumulation of anthropogenic marine debris (AMD) are pervasive problems in coastal urban ecosystems. The biosecurity risks associated with AMD rafting NIMS have been described, but the role of aquaculture derived AMD has not yet been investigated as a biosecurity vector and pathway. This preliminary study targeted 27 beaches along the Coromandel Peninsula, New Zealand, collecting debris from belt transects. Plastic (specifically plastic rope) was the dominant AMD present on beaches. The most common biofouling taxa were hydroids, bryozoans, algae and polychaetes, with one NIMS pest species, Sabella spallanzanii, detected fouling plastic rope. Our findings demonstrate that aquaculture is an AMD (plastic rope) generating activity that creates biosecurity risk by enhancing the spread of NIMS. The rafting of S. spallanzanii on AMD generated at aquaculture facilities is currently an unmanaged pathway within New Zealand that needs attention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. What does impacted look like? High diversity and abundance of epibiota in modified estuaries.

    PubMed

    Clark, Graeme F; Kelaher, Brendan P; Dafforn, Katherine A; Coleman, Melinda A; Knott, Nathan A; Marzinelli, Ezequiel M; Johnston, Emma L

    2015-01-01

    Ecosystems modified by human activities are generally predicted to be biologically impoverished. However, much pollution impact theory stems from laboratory or small-scale field studies, and few studies replicate at the level of estuary. Furthermore, assessments are often based on sediment contamination and infauna, and impacts to epibiota (sessile invertebrates and algae) are seldom considered. We surveyed epibiota in six estuaries in south-east Australia. Half the estuaries were relatively pristine, and half were subject to internationally high levels of contamination, urbanisation, and industrialisation. Contrary to predictions, epibiota in modified estuaries had greater coverage and were similarly diverse as those in unmodified estuaries. Change in epibiota community structure was linearly correlated with sediment-bound copper, and the tubeworm Hydroides elegans showed a strong positive correlation with sediment metals. Stressors such as metal contamination can reduce biodiversity and productivity, but others such as nutrient enrichment and resource provision may obscure signals of impact. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Gender identification of Caspian Terns using external morphology and discriminant function analysis

    USGS Publications Warehouse

    Ackerman, Joshua T.; Takekawa, John Y.; Bluso, J.D.; Yee, J.L.; Eagles-Smith, Collin A.

    2008-01-01

    Caspian Tern (Sterna caspia) plumage characteristics are sexually monochromatic and gender cannot easily be distinguished in the field without extensive behavioral observations. We assessed sexual size dimorphism and developed a discriminant function to assign gender in Caspian Terns based on external morphology. We collected and measured Caspian Terns in San Francisco Bay, California, and confirmed their gender based on necropsy and genetic analysis. Of the eight morphological measurements we examined, only bill depth at the gonys and head plus bill length differed between males and females with males being larger than females. A discriminant function using both bill depth at the gonys and head plus bill length accurately assigned gender of 83% of terns for which gender was known. We improved the accuracy of our discriminant function to 90% by excluding individuals that had less than a 75% posterior probability of correctly being assigned to gender. Caspian Terns showed little sexual size dimorphism in many morphometries, but our results indicate they can be reliably assigned to gender in the field using two morphological measurements.

  3. Reproduction and organochlorine contaminants in terns at San Diego Bay

    USGS Publications Warehouse

    Ohlendorf, H.M.; Schaffner, F.C.; Custer, T.W.; Stafford, C.J.

    1985-01-01

    In 1981, we studied Caspian Terns (Sterna caspia) and Elegant Terns (S. elegans) nesting at the south end of San Diego Bay, California. Randomly collected Caspian Tern eggs contained signficantly (P < 0.05) higher mean concentrations of DDE (9.30 ppm) than did Elegant Tern eggs (3.79 ppm). DDE may have had an adverse effect on Caspian Tern reproduction but the relationship between hatching success and DDE concentration was not clear. We found an unusually high incidence of chicks (4.6%) that died in hatching. Caspian Tern eggs that broke during incubation or contained chicks that died while hatching had shells that were significantly (P < 0.05) thinner than eggs collected before 1947, and DDE was associated with reductions in shell thickness index (i.e., lowered eggshell density). Fish brought to Caspian Tern chicks contained up to 3.0 ppm DDE and 1.1 ppm PCBs. Organochlorine concentration brains of terns found dead were not high enough to suggest such poisoning as a cause of death.

  4. Congener-specific polychlorinated biphenyl patterns in eggs of aquatic birds from the lower Laguna Madre, Texas

    USGS Publications Warehouse

    Mora, Miguel A.

    1996-01-01

    Eggs from four aquatic bird species nesting in the Lower Laguna Madre, Texas, were collected to determine differences and similarities in the accumulation of congener-specific polychlorinated biphenyls (PCBs) and to evaluate PCB impacts on reproduction. Because of the different toxicities of PCB congeners, it is important to know which congeners contribute most to total PCBs. The predominant PCB congeners were 153, 138, 180, 110, 118, 187, and 92. Collectively, congeners 153, 138, and 180 accounted for 26 to 42% of total PCBs. Congener 153 was the most abundant in Caspian terns (Sterna caspia) and great blue herons (Ardea herodias) and congener 138 was the most abundant in snowy egrets (Egretta thula) and tricolored herons (Egretta tricolor). Principal component analysis indicated a predominance of higher chlorinated biphenyls in Caspian terns and great blue herons and lower chlorinated biphenyls in tricolored herons. Snowy egrets had a predominance of pentachlorobiphenyls. These results suggest that there are differences in PCB congener patterns in closely related species and that these differences are more likely associated with the species' diet rather than metabolism. Total PCBs were significantly greater (p < 0.05) in Caspian terns than in the other species. Overall, PCBs in eggs of birds from the Lower Laguna Madre were below concentrations known to affect bird reproduction.

  5. Contaminants in eggs of colonial waterbirds and hepatic cytochrome P450 enzyme levels in pipped tern embryos, Washington State

    USGS Publications Warehouse

    Blus, L.J.; Melancon, M.J.; Hoffman, D.J.; Henny, C.J.

    1998-01-01

    Eggs of Forster's terns (Sterna forsteri) collected in 1991 from nesting colonies on Crescent Island (Columbia River) and the Potholes Reservoir in south central Washington generally contained low residues of organochlorine pesticides and metabolites, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, and polychlorinated biphenyls (PCBs). Hepatic cytochrome P450 enzyme activity in pipped embryos of Forster's terns from the two colonies seemed unaffected by contaminants. At Crescent Island, examination of 23 Forster's tern eggs with large embryos (19 viable [10 pipped] and four dead [two pipped]) revealed developmental abnormalities in two viable pipped embryos (missing maxilla and deformed pelvic girdle) and a viable prepipping embryos (shortened beak). Our limited sample sizes and number of compounds analyzed preclude us from determining whether or not the abnormalities are related to contaminants. No abnormalities were noted in 10 pipped eggs (nine viable and one dead at collection) of Forster's terns collected from the Potholes Reservoir colony. Eggs of Caspian terns (Sterna caspia) collected from Crescent Island in 1991 also contained generally low residues of contaminants, only one developmental abnormality was noted, and limited data indicated that cytochrome P450 enzyme activity apparently was unaffected by contaminants. Organochlorine contaminants were generally low in addled eggs of American white pelicans (Pelecanus erythrorhynchos) collected from Crescent Island in 1994

  6. Contaminants in eggs of colonial waterbirds and hepatic cytochrome P450 enzyme levels in pipped tern embryos, Washington State.

    PubMed

    Blus, L J; Melancon, M J; Hoffman, D J; Henny, C J

    1998-10-01

    Eggs of Forster's terns (Sterna forsteri) collected in 1991 from nesting colonies on Crescent Island (Columbia River) and the Potholes Reservoir in south central Washington generally contained low residues of organochlorine pesticides and metabolites, 2,3,7, 8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, and polychlorinated biphenyls (PCBs). Hepatic cytochrome P450 enzyme activity in pipped embryos of Forster's terns from the two colonies seemed unaffected by contaminants. At Crescent Island, examination of 23 Forster's tern eggs with large embryos (19 viable [10 pipped] and four dead [two pipped]) revealed developmental abnormalities in two viable pipped embryos (missing maxilla and deformed pelvic girdle) and a viable prepipping embryo (shortened beak). Our limited sample sizes and number of compounds analyzed preclude us from determining whether or not the abnormalities are related to contaminants. No abnormalities were noted in 10 pipped eggs (nine viable and one dead at collection) of Forster's terns collected from the Potholes Reservoir colony. Eggs of Caspian terns (Sterna caspia) collected from Crescent Island in 1991 also contained generally low residues of contaminants, only one developmental abnormality was noted, and limited data indicated that cytochrome P450 enzyme activity apparently was unaffected by contaminants. Organochlorine contaminants were generally low in addled eggs of American white pelicans (Pelecanus erythrorhynchos) collected from Crescent Island in 1994.

  7. Mercury exposure may influence fluctuating asymmetry in waterbirds.

    PubMed

    Herring, Garth; Eagles-Smith, Collin A; Ackerman, Joshua T

    2017-06-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  8. Congener-specific polychlorinated biphenyl patterns in eggs of aquatic birds from the Lower Laguna Madre, Texas

    SciTech Connect

    Mora, M.A.

    1996-06-01

    Eggs from four aquatic bird species nesting in the Lower Laguna Madre, Texas, were collected to determine differences and similarities in the accumulation of congener-specific polychlorinated biphenyls (PCBs) and to evaluate PCB impacts on reproduction. Because of the different toxicities of PCB congeners, it is important to know which congeners contribute most to total PCBs. The predominant PCB congeners were 153, 138, 180, 110, 118, 187, and 92. Collectively, congeners 153, 138, and 180 accounted for 26 to 42% of total PCBs. Congener 153 was the most abundant in Caspian terns (Sterna caspia) and great blue herons (Ardea herodias) and congener 138 was the most abundant in snowy egrets (Egretta thula) and tricolored herons (Egretta tricolor). Principal component analysis indicated a predominance of higher chlorinated biphenyls in Caspian terns and great blue herons and lower chlorinated biphenyls in tricolored herons. Snowy egrets had a predominance of pentachlorobiphenyls. These results suggest that there are differences in PCB congener patterns in closely related species and that these differences are more likely associated with the species` diet rather than metabolism. Total PCBs were significantly greater (p < 0.05) in Caspian terns than in the other species. Overall, PCBs in eggs of birds from the Lower Laguna Madre were below concentrations known to affect bird reproduction.

  9. Abundance and diversity of ammonia-oxidizing archaea and bacteria in the rhizosphere soil of three plants in the Ebinur Lake wetland.

    PubMed

    He, Yuan; Hu, Wenge; Ma, Decao; Lan, Hongzhu; Yang, Yang; Gao, Yan

    2017-07-01

    Ammonia oxidation is carried out by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). The Ebinur Lake wetland is the best example of a temperate arid zone wetland ecosystem in China. Soil samples were collected from rhizosphere and non-rhizosphere soil containing Halocnemum strobilaceum (samples H and H'), Phragmites australis (samples R and R'), and Karelinia caspia (samples K and K') to study the relationship between environmental factors and the community structure of AOB and AOA. Phylogenetic analysis showed that the AOA sequences belonged to the Nitrosopumilus and Nitrososphaera clusters. AOB were grouped into Nitrosospira sp. and Nitrosomonas sp. Quantitative polymerase chain reaction results showed that the AOA abundance ranged from 2.09 × 10(4) to 2.94 × 10(5) gene copies/g soil. The highest number of AOA was detected in sample K, followed by samples R and H. AOB abundance varied between 2.91 × 10(5) and 1.05 × 10(6) gene copies/g soil, which was higher than that of AOA. Redundancy analysis indicated that electrical conductivity, pH, and NH4(+)-N might influence the community structure of AOA and AOB. AOB might play a more crucial role than AOA in ammonia oxidation based on AOB's higher diversity and abundance in the Ebinur Lake wetland in Xinjiang.

  10. Stable isotope analysis of avian eggs: Determining diet, feeding source and role of endogenous reserves

    SciTech Connect

    Hobson, K.A.

    1995-12-31

    Contemporary and archived avian eggs have been used extensively as a means of assessing and monitoring contaminants in the environment. Eggs can also be analyzed for stable-isotope ratios to provide dietary information that may be used to link diet of laying females with contaminant levels in eggs. Various egg components can provide integrated dietary information based on periods ranging from about a day (e.g. albumen, shell carbonate) to a week (egg yolk). In addition, some species may mobilize stored proteins and lipids from endogenous reserves during egg formation and this needs to be considered when correlating contaminant levels in eggs with dietary patterns in adult females. The role of endogenous reserves in egg formation may be assessed if individuals move between food webs with distinct isotopic profiles. This approach is illustrated using isotopic investigations of captive quail, falcons and waterfowl raised on controlled diets and of wild birds (Phalacrocorax auritus, Larus argentatus, Stema caspia, Chen caerulescens) that migrate between marine and terrestrial biomes using a variety of isotopes ({sup 13}C, {sup 15}N, {sup 34}S and D) . Whereas {sup 15}N measurements may provide information primarily of trophic level, {sup 13}C, {sup 34}S and D measurements reveal important information on source of feeding and origin of endogenous reserves.

  11. Effects of nest density, location, and timing on breeding success of Caspian Terns

    USGS Publications Warehouse

    Antolos, Michelle; Roby, D.D.; Lyons, Donald E.; Anderson, Scott K.; Collis, K.

    2006-01-01

    One of the proposed benefits of colonial nesting in birds is the protection afforded against avian predators. This advantage may be counter-balanced by the negative effects of intraspecific aggression on breeding success. Effects of nest density, nest location within the colony, and timing of nest initiation on productivity of Caspian Terns (Sterna caspia) were investigated on Crescent Island in the mid-Columbia River, Washington, USA. In the absence of intense nest predation at the Crescent Island tern colony, it was hypothesized that nest density would be negatively associated with productivity. A rangefinder was used to determine spatial distribution of Caspian Tern nests, and these data used to calculate nest characteristics (nest density, nearest neighbor distance, and distance to colony edge) for a randomly-selected subset of nests monitored for nest chronology and productivity. Productivity did not differ between nests in high- and low-density areas of the colony, and was positively associated with earlier nest initiation. Early nests were more productive, were located in areas of higher nest density, and were further from the colony edge than late nests. The strong effect of timing may have been attributable to seasonal declines in prey resources for terns at this site. Our results suggest that Caspian Terns nesting at the highest densities observed in this study did not incur immediate reproductive costs, despite increased potential for encounters between chicks and aggressive conspecific adults.

  12. Tracking overwintering areas of fish-eating birds to identify mercury exposure.

    PubMed

    Lavoie, Raphael A; Kyser, T Kurt; Friesen, Vicki L; Campbell, Linda M

    2015-01-20

    Migration patterns are believed to greatly influence concentrations of contaminants in birds due to accumulation in spatially and temporally distinct ecosystems. Two species of fish-eating birds, the Double-crested Cormorant (Phalacrocorax auritus) and the Caspian Tern (Hydroprogne caspia) breeding in Lake Ontario were chosen to measure the impact of overwintering location on mercury concentrations ([Hg]). We characterized (1) overwintering areas using stable isotopes of hydrogen (δ(2)H) and band recoveries, and (2) overwintering habitats by combining information from stable isotopes of sulfur (δ(34)S), carbon (δ(13)C), nitrogen (δ(15)N), and δ(2)H in feathers grown during the winter. Overall, overwintering location had a significant effect on [Hg]. Both species showed high [Hg] in (13)C-rich habitats. In situ production of Hg (e.g., through sulfate reducing bacteria in sediments) and allochthonous import could explain high [Hg] in birds visiting (13)C-rich habitats. Higher [Hg] were found in birds with high δ(2)H, suggesting that Hg is more bioavailable in southern overwintering locations. Hotspot maps informed that higher [Hg] in birds were found at the limit of their southeastern overwintering range. Mercury concentrations in winter feathers were positively related to predicted spatial pattern of [Hg] in fish using the National Descriptive Model of Mercury in Fish (NDMMF) based on bird spatial assignment (using δ(2)H). This study indicates that the overwintering location greatly influences [Hg].

  13. Redistribution and growth of the Caspian Tern population in the Pacific Coast region of north America, 1981-2000

    USGS Publications Warehouse

    Suryan, R.M.; Craig, D.P.; Roby, D.D.; Chelgren, N.D.; Collis, K.; Shuford, W.D.; Lyons, Donald E.

    2004-01-01

    We examined nesting distribution and demography of the Pacific Coast population of Caspian Terns (Sterna caspia) using breeding records and band recoveries spanning two decades since the first population assessment. Since 1980, population size has more than doubled to about 12 900 pairs, yet the proportion of the population nesting at inland (18%) versus coastal sites (82%) has remained constant. Although the breeding range of the Pacific Coast population has expanded northward into Alaska and farther south in Mexico, there was no net latitudinal shift in the distribution of breeding pairs or new colonies. The distribution of breeding birds among areas changed dramatically, however, with 69% of breeding terns now nesting in Oregon (primarily in the Columbia River estuary) versus 4% during the late 1970s. During the past 20 years, there has continued to be a greater proportion of Caspian Terns breeding at anthropogenic sites compared to natural sites. Estimated annual survival rates for hatch-year and after-third-year birds during 1981-1998 were greater than during 1955-1980, consistent with the higher rate of population increase in recent decades. Fecundity required to maintain a stable population (?? = 1) was estimated at 0.32-0.74 fledglings pair-1, depending on band recovery probabilities for sub-adults. Caspian Terns readily moved among breeding sites and rapidly colonized new areas; however, a greater concentration of breeding Caspian Terns among fewer colonies in response to anthropogenic factors is an important conservation concern for this species.

  14. Contamination of mercury during the wintering period influences concentrations at breeding sites in two migratory piscivorous birds.

    PubMed

    Lavoie, Raphael A; Baird, Christopher J; King, Laura E; Kyser, T Kurt; Friesen, Vicki L; Campbell, Linda M

    2014-12-02

    Many aquatic fish-eating birds migrate long distances and are exposed to different mercury concentrations ([Hg]) during their annual cycle. Here we examined the importance of migration on [Hg] in two colonial migratory fish-eating bird species. We determined temporal trends of [Hg] and stable isotopes of carbon (δ(13)C) and nitrogen (δ(15)N) during the annual cycle in Double-crested Cormorants (Phalacrocorax auritus) and Caspian Terns (Hydroprogne caspia) breeding in Lake Ontario by a repeated sampling of breast feathers and blood from recaptured individuals. We found an effect of previous winter [Hg], species, sex, and location to explain variations of Hg at breeding sites. This suggests Hg carryover from winter to summer periods and that variations of [Hg] in the summer are partially explained by [Hg] in the winter. Carryover of Hg among seasons and slow changes in [Hg] over time were found especially for individuals in high winter exposure groups, suggesting a slow depuration rate and a fast uptake rate for both species. In contrast, stable isotope values rapidly switched to reach equilibrium at a similar midpoint regardless of winter habitat or diet suggesting minimal carryover of isotopic signatures. The potential of Hg carryover from wintering sites indicates that Hg concentrations in birds at a given time may be influenced by previous exposure from distant locations.

  15. Functional, biochemical, and histological biomarkers for immunocompetence in fish-eating birds of the Great Lakes

    SciTech Connect

    Grasman, K.A.; Scanlon, P.F.; Fox, G.A.

    1995-12-31

    The authors studied the effects of environmental contaminants on immune function and related biochemical and histological biomarkers in herring gulls (Larus argentatus) and Caspian terns (Sterna caspia) from the Great Lakes. An epidemiological analysis strongly supported the hypothesis that suppression of T-cell-mediated immunity was associated with high perinatal exposure to persistent organochlorines (primarily PCBs). Suppression of T cell function (measured by the phytohemagglutinin skin test) was most severe in colonies in Lake Ontario and Saginaw Bay for both species and in western Lake Erie (1992) for herring gulls. In herring gull chicks, the mass of the thymus decreased as liver EROD increased. Both species exhibited biologically significant differences among sites in anti-SRBC antibody titers, but there were few associations with organochlorines. In Caspian terns and, to a lesser degree, in herring gulls, plasma retinol decreased as organochlorines increased. In both species, plasma thyroxine concentrations differed significantly among sites, but there were no apparent associations with contaminants. Although thyroxine and retinol often are associated with immune function in laboratory studies, there were few consistent relationships between these variables and T-cell- and antibody-mediated immunity in this field study. These biochemical variables may be poor surrogate biomarkers for immune function in wild birds, although they are important indicators for other physiological systems. The histology of the thymus, bursa of Fabricius, and spleen were examined for developmental and functional abnormalities and the presence of infections.

  16. Organochlorine-induced immunosuppression in fish-eating birds of the Great Lakes

    SciTech Connect

    Grasman, K.A.; Scanlon, P.F.; Fox, G.A.

    1995-12-31

    This investigation studied the effects of environmental contaminants on immune function in fish-eating birds of the Great Lakes and evaluated the use of immunological tests as biomarkers for contaminant exposure in wild birds. During 1991--1994, specific immune functions and general hematological parameters were measured in herring gull (Larus argentatus) and Caspian tern (Stema caspia) chicks. Study sites were chosen across a wide range of organochlorine contamination caused primarily by PCBs. In herring gull adults, the heterophil to lymphocyte ratio decreased as liver EROD, an index of contaminant exposure, increased, In herring gull chicks, thymus mass decreased as EROD increased. At highly contaminated sites, gull and tern chicks showed a marked reduction in T cell-mediated immunity as measured by the phytohemagglutinin skin test. The thymic atrophy and T cell suppression were consistent with documented effects of PCBs in laboratory animals during development and growth. In both species, chicks exhibited biologically significant differences in antibody production among sites, but any relationships to contaminants or other factors remain unclear. In laboratory animals, PCBs exhibit variable effects on antibody production. Structural and functional parameters related to the immune system are useful biomarkers for assessing the effects of contaminants on wild birds.

  17. Environmental contaminants in eggs of California least terns (Sterna antillarum browni)

    SciTech Connect

    Hothem, R.L.; Zador, S.G.

    1995-11-01

    A severe decline in the coastal breeding population of California least terns (Sterna antillarum browni) in California and Baja California prompted both State and Federal governments to designate it an endangered species in 1970. Significant losses of nesting and feeding habitat have contributed greatly to the decline of this subspecies. However, environmental contaminants, such as organochlorine compounds and metals, may also have contributed to the decline. California least terns are primarily piscivorous during the nesting period, feeding predominantly on jack-smelt, topsmelt, and northern anchovy. Topsmelt had the highest levels of DDE (p,p`-DDE) (up to 3 {mu}g/g wet wt) of fish collected from San Diego Bay. Eggs of Caspian terns (S.caspia) from that study contained up to 56 {mu}g/g DDE, and DDE was associated with a reduction in eggshell thickness as determined by the thickness index. In addition to shell deficiencies, organochlorines can also cause reduced egg production, aberrant incubation behavior, delayed ovulation, embryotoxicosis, and mortality of chicks and adults. Mercury (Hg) and selenium (Se) have caused decreased hatchability, altered nesting behavior, and embryotoxicosis in birds in field and laboratory studies. Our objective was to evaluate the role of contaminants in the decline of California least terns. 22 refs., 1 fig., 2 tabs.

  18. Mercury exposure may influence fluctuating asymmetry in waterbirds

    USGS Publications Warehouse

    Herring, Garth; Eagles-Smith, Collin A.; Ackerman, Josh

    2017-01-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds.

  19. Drag of Clean and Fouled Net Panels--Measurements and Parameterization of Fouling.

    PubMed

    Gansel, Lars Christian; Plew, David R; Endresen, Per Christian; Olsen, Anna Ivanova; Misimi, Ekrem; Guenther, Jana; Jensen, Østen

    2015-01-01

    Biofouling is a serious problem in marine aquaculture and it has a number of negative impacts including increased forces on aquaculture structures and reduced water exchange across nets. This in turn affects the behavior of fish cages in waves and currents and has an impact on the water volume and quality inside net pens. Even though these negative effects are acknowledged by the research community and governmental institutions, there is limited knowledge about fouling related effects on the flow past nets, and more detailed investigations distinguishing between different fouling types have been called for. This study evaluates the effect of hydroids, an important fouling organism in Norwegian aquaculture, on the forces acting on net panels. Drag forces on clean and fouled nets were measured in a flume tank, and net solidity including effect of fouling were determined using image analysis. The relationship between net solidity and drag was assessed, and it was found that a solidity increase due to hydroids caused less additional drag than a similar increase caused by change in clean net parameters. For solidities tested in this study, the difference in drag force increase could be as high as 43% between fouled and clean nets with same solidity. The relationship between solidity and drag force is well described by exponential functions for clean as well as for fouled nets. A method is proposed to parameterize the effect of fouling in terms of an increase in net solidity. This allows existing numerical methods developed for clean nets to be used to model the effects of biofouling on nets. Measurements with other types of fouling can be added to build a database on effects of the accumulation of different fouling organisms on aquaculture nets.

  20. Drag of Clean and Fouled Net Panels – Measurements and Parameterization of Fouling

    PubMed Central

    Gansel, Lars Christian; Plew, David R.; Endresen, Per Christian; Olsen, Anna Ivanova; Misimi, Ekrem; Guenther, Jana; Jensen, Østen

    2015-01-01

    Biofouling is a serious problem in marine aquaculture and it has a number of negative impacts including increased forces on aquaculture structures and reduced water exchange across nets. This in turn affects the behavior of fish cages in waves and currents and has an impact on the water volume and quality inside net pens. Even though these negative effects are acknowledged by the research community and governmental institutions, there is limited knowledge about fouling related effects on the flow past nets, and more detailed investigations distinguishing between different fouling types have been called for. This study evaluates the effect of hydroids, an important fouling organism in Norwegian aquaculture, on the forces acting on net panels. Drag forces on clean and fouled nets were measured in a flume tank, and net solidity including effect of fouling were determined using image analysis. The relationship between net solidity and drag was assessed, and it was found that a solidity increase due to hydroids caused less additional drag than a similar increase caused by change in clean net parameters. For solidities tested in this study, the difference in drag force increase could be as high as 43% between fouled and clean nets with same solidity. The relationship between solidity and drag force is well described by exponential functions for clean as well as for fouled nets. A method is proposed to parameterize the effect of fouling in terms of an increase in net solidity. This allows existing numerical methods developed for clean nets to be used to model the effects of biofouling on nets. Measurements with other types of fouling can be added to build a database on effects of the accumulation of different fouling organisms on aquaculture nets. PMID:26151907

  1. Development and short-term dynamics of macrofouling assemblages on fish-cage nettings in a tropical estuary

    NASA Astrophysics Data System (ADS)

    Madin, John; Chong, V. C.; Basri, Badrulnizam

    2009-06-01

    A study was conducted at a fish culture farm in the Jaha River estuary, Malaysia, to examine the structure and development of macrofouling assemblages on floating net-cages. The study was conducted during the dry (August-October 2001) and wet (December-February 2002) seasons. Biofouling on 1.6 cm mesh net panels (size 0.2 m × 2 m) suspended inside (P, T) and outside (O) experimental net-cages was monitored every week until net openings were completely occluded by macrofouling organisms (8 wk and 12 wk for dry and wet seasons respectively). Seven species (6 phyla) of sessile organisms and 23 species (3 phyla) of non-sessile associates were recorded. Macro-colonization of net panels began with the hydroid Plumularia sp. irrespective of season and treatment (P, T, and O), while other species only appeared after 1 or 2 weeks of immersion. Inside net-cages where water flow was slow (mean < 6 cm s -1 at 0.50-0.75 m depth); macroalgae ( Polysiphonia sp.), anthozoans (unidentified anemone), barnacles ( Balanus amphitrite), amphipods ( Gammaropsis sp. & Photis sp.), and tanaids ( Leptognathia sp.) were dominant on the net panels during the dry season. In the wet season, hydroid ( Plumularia sp.), mussel ( Xenostrobus mangle), and nematode abundance were however significant. With stronger water flow (mean ≈ 20 cm s -1) as occurring outside the net-cages, macrofouling assemblages for both seasons comprised mainly Plumularia sp. and Gammaropsis sp. The macrofouling assemblage showed a clear succession of species that occupied different layers of the net panels. The study shows that while organic enrichment and retarded water flow together enhance the development of macrofouling assemblages, salinity, depth, substrate (net) area and species competition specifically influence community structure, colonization, and depth distribution of the macrofouling organisms.

  2. The role of mid-palaeozoic mesofossils in the detection of early bryophytes.

    PubMed Central

    Edwards, D

    2000-01-01

    Recently discovered Silurian and Devonian coalified mesofossils provide an additional source of data on early embryophytes. Those reviewed in this paper are considered of some relevance to understanding the early history of bryophytes while highlighting the difficulties of recognizing bryophytes in often very fragmentary fossils. The first group comprises sporophytes in which terminal sporangia contain permanent dyads and tetrads. Such spores (cryptospores) are similar to those found dispersed in older Ordovician and Silurian strata, when they are considered evidence for a land vegetation of embryophytes at a bryophyte grade. The phylogenetic significance of plants, where the axes associated with both dyad- and tetrad-containing sporangia are branching, a character state not found in extant bryophytes, is discussed. The second group comprises axial fossils, many with occasional stomata, in which central conducting strands include G-type tracheids and a number of novel types of elongate elements not readily compared with those of any tracheophyte. They include smooth-walled, evenly thickened elongate elements as well as those with numerous branching +/- anastomosing projections into the lumen. Some of the latter bear an additional microporate layer, but the homogenized lateral walls between adjacent cells are never perforate. Such cells, which occur in various combinations in central strands, are compared with the leptoids and hydroids of mosses, hydroids of liverworts and presumed water-conducting cells in coeval Lower Devonian plants such as Aglaophyton. It is concluded that lack of information on the chemistry of their walls hampers sensible assessment of their functions and the affinities of the plants. Finally, a minute fossil, comprising an elongate sporangium in which a central cylindrical cavity containing spores and possible elaters terminates in a complex poral dehiscence apparatus, is used to exemplify problems of identifying early bryophytes. It is

  3. Polyunsaturated-fatty-acid oxidation in Hydra: regioselectivity, substrate-dependent enantioselectivity and possible biological role.

    PubMed Central

    Di Marzo, V; Gianfrani, C; De Petrocellis, L; Milone, A; Cimino, G

    1994-01-01

    A novel and abundant lipoxygenase-like activity converting cis-eicosa-5,8,11,14-tetraenoic acid (arachidonic acid) into (11R)-hydroxyeicosatetraenoic acid has been recently described in homogenates of the freshwater hydrozoan Hydra vulgaris. In this study, other substrates for this enzyme were selected from the polyunsaturated fatty acids (PUFAs) present in H. vulgaris, and the chemical natures of the hydroperoxy and hydroxy derivatives produced, as well as the activity of some of the latter on hydroid tentacle regeneration, were investigated. The highest conversion among C20 fatty acids was observed for arachidonic acid, and among C18 fatty acids for cis-octadeca-9,12,15- and cis-octadeca-6,9,12-trienoic (alpha- and gamma-linolenic) acids. Cis double bonds on the 10th carbon atom from the aliphatic end of the substrate (e.g. C-9, C-11 and C-13 respectively in C18, C20 and C22 PUFAs) were regiospecifically peroxidized. Conversely, trans-octadeca-9,12-dienoic (linoelaidic) acid was not a substrate for lipoxygenase activity. Enantioselectivity of lipoxygenation depended on the degree of unsaturation of the substrate, with the amount of the R enantiomer increasing when passing, for example, from cis-eicosa-11,14-dienoic to cis-eicosa-5,8,11,14,17-pentaenoic acid. Regiospecific formation of keto acids was observed only when incubating C18 PUFAs. Commercially available hydroxyacids corresponding to the reaction products of some of the most abundant H. vulgaris PUFAs were tested for effects on Hydra tentacle regeneration. An enhancement of average tentacle number, in a fashion depending on the stereochemistry and on the number of double bonds, was found for two compounds, thus suggesting for the 11-lipoxygenase-like enzyme a role in the production of metabolites potentially active in the control of hydroid regenerative processes. PMID:8002956

  4. Cost-effective management alternatives for Snake river chinook salmon: A biological-economic synthesis

    USGS Publications Warehouse

    Halsing, D.L.; Moore, M.R.

    2008-01-01

    The mandate to increase endangered salmon populations in the Columbia River Basin of North America has created a complex, controversial resource-management issue. We constructed an integrated assessment model as a tool for analyzing biological-economic trade-offs in recovery of Snake River spring- and summer-run chinook salmon (Oncorhynchus tshawytscha). We merged 3 frameworks: a salmon-passage model to predict migration and survival of smolts; an age-structured matrix model to predict long-term population growth rates of salmon stocks; and a cost-effectiveness analysis to determine a set of least-cost management alternatives for achieving particular population growth rates. We assessed 6 individual salmon-management measures and 76 management alternatives composed of one or more measures. To reflect uncertainty, results were derived for different assumptions of effectiveness of smolt transport around dams. Removal of an estuarine predator, the Caspian Tern (Sterna caspia), was cost-effective and generally increased long-term population growth rates regardless of transport effectiveness. Elimination of adult salmon harvest had a similar effect over a range of its cost estimates. The specific management alternatives in the cost-effective set depended on assumptions about transport effectiveness. On the basis of recent estimates of smolt transport effectiveness, alternatives that discontinued transportation or breached dams were prevalent in the cost-effective set, whereas alternatives that maximized transportation dominated if transport effectiveness was relatively high. More generally, the analysis eliminated 80-90% of management alternatives from the cost-effective set. Application of our results to salmon management is limited by data availability and model assumptions, but these limitations can help guide research that addresses critical uncertainties and information. Our results thus demonstrate that linking biology and economics through integrated models can

  5. Validating growth and development of a seabird as an indicator of food availability: captive-reared Caspian Tern chicks fed ad libitum and restricted diets

    USGS Publications Warehouse

    Lyons, Donald E.; Roby, Daniel D.

    2011-01-01

    For seabirds raising young under conditions of limited food availability, reducing chick provisioning and chick growth rates are the primary means available to avoid abandonment of a breeding effort. For most seabirds, however, baseline data characterizing chick growth and development under known feeding conditions are unavailable, so it is difficult to evaluate chick nutritional status as it relates to foraging conditions near breeding colonies. To address this need, we examined the growth and development of young Caspian Terns (Hydroprogne caspia), a cosmopolitan, generalist piscivore, reared in captivity and fed ad libitum and restricted (ca. one-third lower caloric intake) diets. Ad libitum-fed chicks grew at similar rates and achieved a similar size at fledging as previously documented for chicks in the wild and had energetic demands that closely matched allometric predictions. We identified three general characteristics of food-restricted Caspian Tern chicks compared to ad libitum chicks: (1) lower age-specific body mass, (2) lower age-specific skeletal and feather size, such as wing chord length, and (3) heightened levels of corticosterone in blood, both for baseline levels and in response to acute stress. Effects of diet restriction on feather growth (10-11% slower growth in diet-restricted chicks) were less pronounced than effects on structural growth (37-52% slower growth) and body mass (24% lower at fledging age), apparently due to preferential allocation of food resources to maintain plumage growth. Our results suggest that measurements of chick body mass and feather development (e.g., wing chord or primary length) or measurement of corticosterone levels in the blood would allow useful evaluation of the nutritional status of chicks reared in the wild and of food availability in the foraging range of adults. Such evaluations could also inform demography studies (e.g., predict future recruitment) and assist in evaluating designated piscivorous waterbird

  6. Concentrations and time trends of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in aquatic bird eggs from San Francisco Bay, CA 2000-2003

    USGS Publications Warehouse

    She, J.; Holden, A.; Adelsbach, T.L.; Tanner, M.; Schwarzbach, S.E.; Yee, J.L.; Hooper, K.

    2008-01-01

    Concentrations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in 169 avian eggs. We analyzed randomly collected eggs of two species of piscivorous birds: Caspian tern (Sterna caspia) (n = 78) and Forster's tern (Sterna forsteri) (n = 76). We also analyzed fail-to-hatch eggs from two species protected under the Federal Endangered Species Act of 1973, that breed in the San Francisco Bay region: the piscivorous California Least tern (Sterna antillarum brownii) (n = 11) and the omnivorous California Clapper rail (Rallus longirostris obsoletus) (n = 4). San Francisco Bay eggs were collected annually for four years (2000-2003), and additional 20 eggs were collected and analyzed from Gray's Harbor, Washington in 2001. Geometric mean PBDE concentrations did not significantly differ in the three tern species, but concentrations in eggs from the fail to hatch California Clapper rail eggs were significantly lower than those found in the randomly collected tern eggs. Median concentrations of ???PBDEs in Caspian tern eggs for 2000-2003 were 2410, 4730, 3720 and 2880 ng/g lipid weight (lw), respectively, in Forster's terns 1820, 4380, 5460 and 3600 ng/g lw, respectively, and in California Least terns for 2001 and 2002 were 5060 and 5170 ng/g lw, respectively. In contrast, median ???PBDEs concentration in California Clapper rail eggs for 2001 was 379 ng/g lw. Five PBDEs were the major congeners found and decreased in the order BDE-47, -99, -100, -153, and -154. BDE-32, -28, -71, -66, -85, -183 were less prevalent, minor congeners, as was BDE-209, which was measured in a subset of samples. PBDE concentrations in bird eggs from San Francisco Bay were site related. There was no significant difference in PBDE concentrations in Caspian tern eggs from San Francisco Bay and Gray's Harbor, WA. Average PBDE concentrations in eggs did not significantly increase over the period 2000-2003. ?? 2008 Elsevier Ltd. All rights reserved.

  7. Estimating migratory connectivity of birds when re-encounter probabilities are heterogeneous.

    PubMed

    Cohen, Emily B; Hostetler, Jeffrey A; Royle, J Andrew; Marra, Peter P

    2014-05-01

    Understanding the biology and conducting effective conservation of migratory species requires an understanding of migratory connectivity - the geographic linkages of populations between stages of the annual cycle. Unfortunately, for most species, we are lacking such information. The North American Bird Banding Laboratory (BBL) houses an extensive database of marking, recaptures and recoveries, and such data could provide migratory connectivity information for many species. To date, however, few species have been analyzed for migratory connectivity largely because heterogeneous re-encounter probabilities make interpretation problematic. We accounted for regional variation in re-encounter probabilities by borrowing information across species and by using effort covariates on recapture and recovery probabilities in a multistate capture-recapture and recovery model. The effort covariates were derived from recaptures and recoveries of species within the same regions. We estimated the migratory connectivity for three tern species breeding in North America and over-wintering in the tropics, common (Sterna hirundo), roseate (Sterna dougallii), and Caspian terns (Hydroprogne caspia). For western breeding terns, model-derived estimates of migratory connectivity differed considerably from those derived directly from the proportions of re-encounters. Conversely, for eastern breeding terns, estimates were merely refined by the inclusion of re-encounter probabilities. In general, eastern breeding terns were strongly connected to eastern South America, and western breeding terns were strongly linked to the more western parts of the nonbreeding range under both models. Through simulation, we found this approach is likely useful for many species in the BBL database, although precision improved with higher re-encounter probabilities and stronger migratory connectivity. We describe an approach to deal with the inherent biases in BBL banding and re-encounter data to demonstrate that

  8. Estimating migratory connectivity of birds when re-encounter probabilities are heterogeneous

    PubMed Central

    Cohen, Emily B; Hostetler, Jeffrey A; Royle, J Andrew; Marra, Peter P

    2014-01-01

    Understanding the biology and conducting effective conservation of migratory species requires an understanding of migratory connectivity – the geographic linkages of populations between stages of the annual cycle. Unfortunately, for most species, we are lacking such information. The North American Bird Banding Laboratory (BBL) houses an extensive database of marking, recaptures and recoveries, and such data could provide migratory connectivity information for many species. To date, however, few species have been analyzed for migratory connectivity largely because heterogeneous re-encounter probabilities make interpretation problematic. We accounted for regional variation in re-encounter probabilities by borrowing information across species and by using effort covariates on recapture and recovery probabilities in a multistate capture–recapture and recovery model. The effort covariates were derived from recaptures and recoveries of species within the same regions. We estimated the migratory connectivity for three tern species breeding in North America and over-wintering in the tropics, common (Sterna hirundo), roseate (Sterna dougallii), and Caspian terns (Hydroprogne caspia). For western breeding terns, model-derived estimates of migratory connectivity differed considerably from those derived directly from the proportions of re-encounters. Conversely, for eastern breeding terns, estimates were merely refined by the inclusion of re-encounter probabilities. In general, eastern breeding terns were strongly connected to eastern South America, and western breeding terns were strongly linked to the more western parts of the nonbreeding range under both models. Through simulation, we found this approach is likely useful for many species in the BBL database, although precision improved with higher re-encounter probabilities and stronger migratory connectivity. We describe an approach to deal with the inherent biases in BBL banding and re-encounter data to demonstrate

  9. Effect of In Ovo exposure to an organochlorine mixture extracted from double crested cormorant eggs (Phalacrocorax auritus) and PCB 126 on immune function of juvenile chickens.

    PubMed

    Lavoie, E T; Wiley, F; Grasman, K A; Tillitt, D E; Sikarskie, J G; Bowerman, W W

    2007-11-01

    Organochlorine (OC) contaminants including polychlorinated biphenyls (PCBs) and p, p'-dichlorodiphenyldichloroethylene (DDE) have been associated with immune modulation in wild fish-eating birds from the Great Lakes. The objective of this study was to evaluate the immune function of juvenile chickens after in ovo exposure to PCB 126 or an environmentally relevant OC mixture extracted from eggs of double crested cormorants (Phalacrocorax auritus) from Green Bay, Lake Michigan, USA. Fertile white leghorn chicken (Gallus domesticus) eggs were injected before incubation with 0.55-1.79 ng TCDD equivalents (TEQ)/egg PCB 126 and 1.2-4.9 ng TEQs/egg of cormorant egg extract into the air cell in two separate experiments. After hatching, the immune function was tested using in vivo phytohemagglutinin (PHA) skin response in 11-day-old chicks, antibody titers to immunization with sheep red blood cells (SRBC) in 28-day-old chicks, and, at necropsy, thymus and bursal mass and cellularity. PCB 126 decreased antibody titers at all doses and decreased the thymus and bursa index but not cellularity at 1.79 ng TEQ/egg. The cormorant egg extract caused no significant alterations in immune function even though it has been demonstrated as immunotoxic in chicken embryos. However, twofold to threefold increases in total anti-SRBC titers in 28-day-old chicks exposed to 1.2 or 2.4 ng TEQ/egg of cormorant extract were similar to elevations in anti-SRBC titer observed in Caspian tern (Sterna caspia) chicks from a highly OC-contaminated site in Saginaw Bay, Lake Huron. Posthatch exposure to OC through fish consumption in addition to in ovo OC exposure might be associated with the immune modulation reported in wild birds. Chicks in this study might have begun to compensate for embryonic immunotoxicity by the ages at which we studied them.

  10. Use of fatty acid analysis to determine dispersal of caspian terns in the Columbia River Basin, USA.

    PubMed

    Maranto, Christina J; Parrish, Julia K; Herman, David P; Punt, André E; Olden, Julian D; Brett, Michael T; Roby, Daniel D

    2011-08-01

    Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp.), artificially concentrating these prey. We used differences in fatty acid profiles between Caspian Terns (Hydroprogne caspia) at coastal and inland breeding colonies and terns culled by a lethal control program at a mid-Columbia River dam to infer dispersal patterns. We modeled the rate of loss of fatty acid biomarkers, which are fatty acids that can be traced to a single prey species or groups of species, to infer whether and when terns foraging at dams had emigrated from the coast. Nonmetric multidimensional scaling showed that coastal terns had high levels of C(20) and C(22) monounsaturated fatty acids, whereas fatty acids of inland breeders were high in C18:3n3, C20:4n6, and C22:5n3. Models of the rate of loss of fatty acid showed that approximately 60% of the terns collected at Rock Island Dam were unlikely to have bred successfully at local (inland) sites, suggesting that terns foraging at dams come from an extensive area. Fatty acid biomarkers may provide accurate information about patterns of dispersal in animal populations and may be extremely valuable in cases where populations differ demonstrably in prey base. © 2011 Society for Conservation Biology.

  11. Stable carbon isotope analysis of nucleic acids to trace sources of dissolved substrates used by estuarine bacteria.

    PubMed Central

    Coffin, R B; Velinsky, D J; Devereux, R; Price, W A; Cifuentes, L A

    1990-01-01

    The natural abundance of stable carbon isotopes measured in bacterial nucleic acids extracted from estuarine bacterial concentrates was used to trace sources of organic matter for bacteria in aquatic environments. The stable carbon isotope ratios of Pseudomonas aeruginosa and nucleic acids extracted from cultures resembled those of the carbon source on which bacteria were grown. The carbon isotope discrimination between the substrate and total cell carbon from bacterial cultures averaged 2.3% +/- 0.6% (n = 13). Furthermore, the isotope discrimination between the substrate and nucleic acids extracted from bacterial cultures was 2.4% +/- 0.4% (n = 10), not significantly different from the discrimination between bacteria and the substrate. Estuarine water samples were prefiltered through 1-micron-pore-size cartridge filters. Bacterium-sized particles in the filtrates were concentrated with tangential-flow filtration and centrifugation, and nucleic acids were then extracted from these concentrates. Hybridization with 16S rRNA probes showed that approximately 90% of the nucleic acids extracted on two sample dates were of eubacterial origin. Bacteria and nucleic acids from incubation experiments using estuarine water samples enriched with dissolved organic matter from Spartina alterniflora and Cyclotella caspia had stable carbon isotope values similar to those of the substrate sources. In a survey that compared diverse estuarine environments, stable carbon isotopes of bacteria grown in incubation experiments ranged from -31.9 to -20.5%. The range in isotope values of nucleic acids extracted from indigenous bacteria from the same waters was similar, -27.9 to -20.2%. Generally, the lack of isotope discrimination between bacteria and nucleic acids that was noted in the laboratory was observed in the field.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2389930

  12. Diatoms as Proxies for Abrupt Events in the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Skorski, W.; Abbott, D. H.; Recasens, C.; Breger, D. L.

    2014-12-01

    The Hudson River estuary has been subject to many abrupt events throughout its history including hurricanes, droughts and pluvials. Hurricanes in particular are rare, discrete events that if fingerprinted can be used to develop better age models for Hudson River sediments. Proxies use observed physical characteristics or biological assemblages (e.g. diatom and foraminiferal assemblages) as tools to reconstruct past conditions prior to the modern instrumental record. Using a sediment core taken from the Hudson River (CDO2-29A), in New York City, drought and pluvial layers were selected based on Cs-137 dating while hurricane layers were determined from occurrences of tropical to subtropical foraminifera. Contrary to previous studies (Weaver, 1970, Weiss et al, 1978), more than sixty different diatom species have been identified using a scanning electron microscope (SEM). Cosmopolitan, hurricane and drought assemblages have begun to be identified after observing multiple layers (Table 1). Tropical foraminifera dominated by Globigerinoides ruber pink were also found in a hurricane layer that we infer was deposited during Hurricane Belle in 1976. More diatom abundance analyses and cataloged SEM pictures will provide further insight into these proxies. Table 1 Diatom Genera and Species Environment Clarification Cyclotella caspia Planktonic, marine-brackish Cosmopolitan Karayevia clevei Freshwater Cosmopolitan Melosira sp Planktonic, marine Cosmopolitan Thalassiosira sp Marine, brackish Cosmopolitan Staurosirella leptostauron Benthic, freshwater Cosmopolitan Actinoptychus senarius Planktonic or benthic, freshwater to brackish Hurricane and pluvial layers Amphora aff. sp Benthic, marine or freshwater Hurricane layers only Nitzschia sp Benthic, marine or freshwater Hurricane layers only Gomphonema sp Freshwater Hurricane layers only Surirella sp Marine-brackish Drought layer only Triceratium sp Marine Drought layer only Other Genera and species Environment Clarification

  13. Effect of in ovo exposure to an organochlorine mixture extracted from double crested cormorant eggs (Phalacrocorax auritus) and PCB 126 on immune function of juvenile chickens

    USGS Publications Warehouse

    Lavoie, E.T.; Wiley, F.; Grasman, K.A.; Tillitt, D.E.; Sikarskie, J.G.; Bowerman, W.W.

    2007-01-01

    Organochlorine (OC) contaminants including polychlorinated biphenyls (PCBs) and p, p'-dichlorodiphenyldichloroethylene (DDE) have been associated with immune modulation in wild fish-eating birds from the Great Lakes. The objective of this study was to evaluate the immune function of juvenile chickens after in ovo exposure to PCB 126 or an environmentally relevant OC mixture extracted from eggs of double crested cormorants (Phalacrocorax auritus) from Green Bay, Lake Michigan, USA. Fertile white leghorn chicken (Gallus domesticus) eggs were injected before incubation with 0.55-1.79 ng TCDD equivalents (TEQ)/egg PCB 126 and 1.2-4.9 ng TEQs/egg of cormorant egg extract into the air cell in two separate experiments. After hatching, the immune function was tested using in vivo phytohemagglutinin (PHA) skin response in 11-day-old chicks, antibody titers to immunization with sheep red blood cells (SRBC) in 28-day-old chicks, and, at necropsy, thymus and bursal mass and cellularity. PCB 126 decreased antibody titers at all doses and decreased the thymus and bursa index but not cellularity at 1.79 ng TEQ/egg. The cormorant egg extract caused no significant alterations in immune function even though it has been demonstrated as immunotoxic in chicken embryos. However, twofold to threefold increases in total anti-SRBC titers in 28-day-old chicks exposed to 1.2 or 2.4 ng TEQ/egg of cormorant extract were similar to elevations in anti-SRBC titer observed in Caspian tern (Sterna caspia) chicks from a highly OC-contaminated site in Saginaw Bay, Lake Huron. Posthatch exposure to OC through fish consumption in addition to in ovo OC exposure might be associated with the immune modulation reported in wild birds. Chicks in this study might have begun to compensate for embryonic immunotoxicity by the ages at which we studied them. ?? 2007 Springer Science+Business Media, LLC.

  14. Surveillance of ticks and associated pathogens in free-ranging Formosan pangolins (Manis pentadactyla pentadactyla).

    PubMed

    Khatri-Chhetri, Rupak; Wang, Hsi-Chieh; Chen, Chen-Chih; Shih, Han-Chun; Liao, Hsien-Chun; Sun, Ching-Min; Khatri-Chhetri, Nabin; Wu, Hung-Yi; Pei, Kurtis Jai-Chyi

    2016-10-01

    Chinese pangolins are critically endangered insectivorous mammals distributed in several South and Southeast Asian countries. In recent years, there has been an increase in spread of tick-borne diseases in both humans and animals worldwide. Currently, limited information is available on ticks and associated pathogens infesting pangolins. The objective of the present study was to survey ticks and associated pathogens in the Formosan pangolin population in Southeastern Taiwan. Free-ranging Formosan pangolins captured during ecological survey were examined for the presence of ticks. DNA extracted from these ticks was used to identify the tick species and also to detect the tick-borne pathogens, by molecular methods. In the present study, we found 25% (13/52) of pangolins captured during 2012-2014 infested with ixodid ticks. A total of 21 ticks were collected and 3 species were identified: Haemaphysalis hystricis (14/21), Haemaphysalis formosensis (2/21) and Amblyomma testudinarium (5/21). We detected four different tick-borne pathogens, where one was identical to Anaplasma sp. strain An.H1446 while others showed close resemblance to Rickettsia conorii subsp. caspia A-167, Ehrlichia sp. TC251-2 and Cytauxzoon spp., respectively. The present study is the first survey of ticks infesting the free-ranging Chinese pangolins and pathogens harboured by these ticks. This information is important to know the diversity of ticks and tick-borne pathogens, and its conservation significance to pangolins and other sympatric wildlife. Important future step should be regular surveillance of ticks and tick-borne diseases at human-domestic animals-wildlife interface, which can provide a useful insight into the dynamics of these pathogens and can help control and prevent outbreak of zoonoses.

  15. Mercury contamination of fish and shrimp samples available in markets of Mashhad, Iran.

    PubMed

    Vahabzadeh, Maryam; Balali-Mood, Mahdi; Mousavi, Seyed-Reza; Moradi, Valiollah; Mokhtari, Mehrangiz; Riahi-Zanjani, Bamdad

    2013-09-01

    Fish and shrimp are common healthy sources of protein to a large percentage of the world's population. Hence, it is vital to evaluate the content of possible contamination of these marine-foods. Six species of fishes and two species of shrimps were collected from the local markets of Mashhad, Iran. The mercury (Hg) concentration of samples was determined by atomic absorption spectrophotometry using a mercuric hydride system (MHS 10). High concentration of total Hg was found in Clupeonella cultriventris caspia (0.93 ± 0.14 μg/g) while the lowest level was detected in Penaeus indicus (0.37 ± 0.03 μg/g). Mean Hg levels in fish and shrimp samples were 0.77 ± 0.08 μg/g and 0.51 ± 0.05 μg/g, respectively. Farmed species (except for P. indicus) and all samples from Persian Gulf and the Caspian Sea had mean mercury concentrations above 0.5 μg/g, which is the maximum standard level recommended by Joint FAO/WHO/Expert Committee on Food Additives (JECFA). All samples had also mean Hg concentrations that exceeded EPA's established safety level of 0.3 μg/g. A little more extensive analysis of data showed that weekly intake of mercury for the proportion of the Iranian population consuming Hg contaminated fish and shrimp is not predicted to exceed the respective provisional tolerable weekly intakes recommended by JECFA. However, the Iranian health and environmental authorities should monitor Hg contamination of the fishes and shrimps before marketing.

  16. Selenium bioaccumulation and body condition in shorebirds and terns breeding in San Francisco Bay, California, USA

    USGS Publications Warehouse

    Ackerman, Joshua T.; Eagles-Smith, Collin A.

    2009-01-01

    The present study evaluated Se bioaccumulation in four waterbird species (n = 206 birds) that breed within San Francisco Bay, California, USA: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster's terns (Sterna forsteri), and Caspian terns (Hydroprogne caspia). Selenium concentrations were variable and influenced by several factors, including species, region, reproductive stage, age, and sex. Adult Se concentrations (μg/g dry wt) in livers ranged from 3.07 to 48.70 in avocets (geometric mean ± standard error, 7.92 ± 0.64), 2.28 to 41.10 in stilts (5.29 ± 0.38), 3.73 to 14.50 in Forster's terns (7.13 ± 0.38), and 4.77 to 14.40 in Caspian terns (6.73 ± 0.78). Avocets had higher Se concentrations in the North Bay compared to the South Bay, whereas stilt Se concentrations were similar between these regions and Forster's terns had lower Se concentrations in the North Bay compared to the South Bay. Female avocets had higher Se concentrations than male avocets, but this was not the case for stilts and Forster's terns. Of the factors assessed, reproductive stage had the most consistent effect among species. Prebreeding birds tended to have higher liver Se concentrations than breeding birds, but this trend was statistically significant only for Forster's terns. Forster's tern chicks had lower Se concentrations than Forster's tern adults, whereas avocet and stilt adults and chicks were similar. Additionally, body condition was negatively related to liver Se concentrations in Forster's tern adults but not in avocet, stilt, or Caspian tern adults and chicks. These variable results illustrate the complexity of Se bioaccumulation and highlight the need to sample multiple species and examine several factors to assess the impact of Se on wildlife.

  17. Selenium bioaccumulation and body condition in shorebirds and terns breeding in San Francisco Bay, California, USA.

    PubMed

    Ackerman, Joshua T; Eagles-Smith, Collin A

    2009-10-01

    The present study evaluated Se bioaccumulation in four waterbird species (n=206 birds) that breed within San Francisco Bay, California, U.S.A.: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster's terns (Sterna forsteri), and Caspian terns (Hydroprogne caspia). Selenium concentrations were variable and influenced by several factors, including species, region, reproductive stage, age, and sex. Adult Se concentrations (microg/g dry wt) in livers ranged from 3.07 to 48.70 in avocets (geometric mean +/- standard error, 7.92 +/- 0.64), 2.28 to 41.10 in stilts (5.29 +/- 0.38), 3.73 to 14.50 in Forster's terns (7.13 _ 0.38), and 4.77 to 14.40 in Caspian terns (6.73 +/- 0.78). Avocets had higher Se concentrations in the North Bay compared to the South Bay, whereas stilt Se concentrations were similar between these regions and Forster's terns had lower Se concentrations in the North Bay compared to the South Bay. Female avocets had higher Se concentrations than male avocets, but this was not the case for stilts and Forster's terns. Of the factors assessed, reproductive stage had the most consistent effect among species. Prebreeding birds tended to have higher liver Se concentrations than breeding birds, but this trend was statistically significant only for Forster's terns. Forster's tern chicks had lower Se concentrations than Forster's tern adults, whereas avocet and stilt adults and chicks were similar. Additionally, body condition was negatively related to liver Se concentrations in Forster's tern adults but not in avocet, stilt, or Caspian tern adults and chicks. These variable results illustrate the complexity of Se bioaccumulation and highlight the need to sample multiple species and examine several factors to assess the impact of Se on wildlife.

  18. Use of Fatty Acid Analysis to Determine Dispersal of Caspian Terns in the Columbia River Basin, U.S.A.

    USGS Publications Warehouse

    Maranto, C.J.; Parrish, J.K.; Herman, D.P.; Punt, A.E.; Olden, J.D.; Brett, M.T.; Roby, D.D.

    2011-01-01

    Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp.), artificially concentrating these prey. We used differences in fatty acid profiles between Caspian Terns (Hydroprogne caspia) at coastal and inland breeding colonies and terns culled by a lethal control program at a mid-Columbia River dam to infer dispersal patterns. We modeled the rate of loss of fatty acid biomarkers, which are fatty acids that can be traced to a single prey species or groups of species, to infer whether and when terns foraging at dams had emigrated from the coast. Nonmetric multidimensional scaling showed that coastal terns had high levels of C20 and C22 monounsaturated fatty acids, whereas fatty acids of inland breeders were high in C18:3n3, C20:4n6, and C22:5n3. Models of the rate of loss of fatty acid showed that approximately 60% of the terns collected at Rock Island Dam were unlikely to have bred successfully at local (inland) sites, suggesting that terns foraging at dams come from an extensive area. Fatty acid biomarkers may provide accurate information about patterns of dispersal in animal populations and may be extremely valuable in cases where populations differ demonstrably in prey base. ??2011 Society for Conservation Biology.

  19. Isolation and Characterization of a Conserved Domain in the Eremophyte H+-PPase Family

    PubMed Central

    Wang, Yanqin; Jin, Shuangxia; Wang, Maojun; Zhu, Longfu; Zhang, Xianlong

    2013-01-01

    H+-translocating inorganic pyrophosphatases (H+-PPase) were recognized as the original energy donors in the development of plants. A large number of researchers have shown that H+-PPase could be an early-originated protein that participated in many important biochemical and physiological processes. In this study we cloned 14 novel sequences from 7 eremophytes: Sophora alopecuroid (Sa), Glycyrrhiza uralensis (Gu), Glycyrrhiza inflata (Gi), Suaeda salsa (Ss), Suaeda rigida (Sr), Halostachys caspica (Hc), and Karelinia caspia (Kc). These novel sequences included 6 ORFs and 8 fragments, and they were identified as H+-PPases based on the typical conserved domains. Besides the identified domains, sequence alignment showed that there still were two novel conserved motifs. A phylogenetic tree was constructed, including the 14 novel H+-PPase amino acid sequences and the other 34 identified H+-PPase protein sequences representing plants, algae, protozoans and bacteria. It was shown that these 48 H+-PPases were classified into two groups: type I and type II H+-PPase. The novel 14 eremophyte H+-PPases were classified into the type I H+-PPase. The 3D structures of these H+-PPase proteins were predicted, which suggested that all type I H+-PPases from higher plants and algae were homodimers, while other type I H+-PPases from bacteria and protozoans and all type II H+-PPases were monomers. The 3D structures of these novel H+-PPases were homodimers except for SaVP3, which was a monomer. This regular structure could provide important evidence for the evolutionary origin and study of the relationship between the structure and function among members of the H+-PPase family. PMID:23922918

  20. Concentrations and time trends of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in aquatic bird eggs from San Francisco Bay, CA 2000-2003.

    PubMed

    She, Jianwen; Holden, Arthur; Adelsbach, Terrence L; Tanner, Manon; Schwarzbach, Steven E; Yee, Julie L; Hooper, Kim

    2008-08-01

    Concentrations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in 169 avian eggs. We analyzed randomly collected eggs of two species of piscivorous birds: Caspian tern (Sterna caspia) (n=78) and Forster's tern (Sterna forsteri) (n=76). We also analyzed fail-to-hatch eggs from two species protected under the Federal Endangered Species Act of 1973, that breed in the San Francisco Bay region: the piscivorous California Least tern (Sterna antillarum brownii) (n=11) and the omnivorous California Clapper rail (Rallus longirostris obsoletus) (n=4). San Francisco Bay eggs were collected annually for four years (2000-2003), and additional 20 eggs were collected and analyzed from Gray's Harbor, Washington in 2001. Geometric mean PBDE concentrations did not significantly differ in the three tern species, but concentrations in eggs from the fail to hatch California Clapper rail eggs were significantly lower than those found in the randomly collected tern eggs. Median concentrations of SigmaPBDEs in Caspian tern eggs for 2000-2003 were 2410, 4730, 3720 and 2880 ng/g lipid weight (lw), respectively, in Forster's terns 1820, 4380, 5460 and 3600 ng/g lw, respectively, and in California Least terns for 2001 and 2002 were 5060 and 5170 ng/g lw, respectively. In contrast, median SigmaPBDEs concentration in California Clapper rail eggs for 2001 was 379 ng/g lw. Five PBDEs were the major congeners found and decreased in the order BDE-47, -99, -100, -153, and -154. BDE-32, -28, -71, -66, -85, -183 were less prevalent, minor congeners, as was BDE-209, which was measured in a subset of samples. PBDE concentrations in bird eggs from San Francisco Bay were site related. There was no significant difference in PBDE concentrations in Caspian tern eggs from San Francisco Bay and Gray's Harbor, WA. Average PBDE concentrations in eggs did not significantly increase over the period 2000-2003.

  1. Contaminant effects on Great Lakes' fish-eating birds: a population perspective

    USGS Publications Warehouse

    Heinz, G.H.; Kendall, Ronald J.; Dickerson, Richard L.; Giesy, John P.; Suk, William P.

    1998-01-01

    Preventing environmental contaminants from reducing wildlife populations is the greatest concern in wildlife toxicology. In the Great Lakes, environmental contaminants have a history of reducing populations of many species of fish-eating birds. Endocrine effects may have contributed to declines in fish-eating bird populations, but the overriding harm was caused by DDE-induced eggshell thinning. Toxic effects may still be occurring today, but apparently they are not of a sufficient magnitude to depress populations of most fish-eating birds. Once DDE levels in the Great Lakes declined, eggshells of birds began to get thicker and reproductive success improved. Populations of double-crested cormorants (Phalacrocorax auritus) and ring-billed gulls (Larus delawarensis) have increased dramatically since the bans on DDT and other organochlorine pesticides. Bald eagles (Haliaeetus leucocephalus) are still not reproducing at a normal rate along the shores of the Great Lakes, but success is much improved compared to earlier records when eggshell thinning was worse. Other species, such as herring gulls (Larus argentatus) and black-crowned night-herons (Nycticorax nycticorax), seem to be having improved reproductive success, but data on Great Lakes'-wide population changes are incomplete. Reproductive success of common terns (Sterna hirundo), Caspian terns (Sterna caspia), and Forster's terns (Sterna forsteri) seems to have improved in recent years, but, again, data on population changes are not very complete, and these birds face many habitat related problems as well as contaminant problems. Although contaminants are still producing toxic effects, and these effects may include endocrine disfunction, fish-eating birds in the Great Lakes seem to be largely weathering these effects, at least as far as populations are concerned. A lack of obvious contaminant effects on populations of fish-eating birds in the Great Lakes, however, should not be equated with a lack of any harm to

  2. Effects of colony relocation on diet and productivity of Caspian terns

    USGS Publications Warehouse

    Roby, D.D.; Collis, K.; Lyons, Donald E.; Craig, D.P.; Adkins, J.Y.; Myers, A.M.; Suryan, R.M.

    2002-01-01

    We investigated the efficacy of management to reduce the impact of Caspian tern (Sterna caspia) predation on survival of juvenile salmonids (Oncorhynchus spp.) in the Columbia River estuary. Resource managers sought to relocate approximately 9,000 pairs of terns nesting on Rice Island (river km 34) to East Sand Island (river km 8), where terns were expected to prey on fewer juvenile salmonids. Efforts to attract terns to nest on East Sand Island included creation of nesting habitat, use of social attraction techniques, and predator control, with concurrent efforts to discourage terns from nesting on Rice Island. This approach was successful in completely relocating the tern colony from Rice Island to East Sand Island by the third breeding season. Juvenile salmonids decreased and marine forage fishes (i.e., herring, sardine, anchovy, smelt, surfperch, Pacific sand lance) increased in the diet of Caspian terns nesting on East Sand Island, compared with terns nesting on Rice Island. During 1999 and 2000, the diet of terns nesting on Rice Island consisted of 77% and 90% juvenile salmonids, respectively, while during 1999, 2000, and 2001, the diet of terns nesting on East Sand Island consisted of 46%, 47%, and 33% juvenile salmonids, respectively. Nesting success of Caspian terns was consistently and substantially higher on East Sand Island than on Rice Island. These results indicate that relocating the Caspian tern colony was an effective management action for reducing predation on juvenile salmonids without harm to the population of breeding terns, at least in the short term. The success of this management approach largely was a consequence of the nesting and foraging ecology of Caspian terns: the species shifts breeding colony sites frequently in response to changing habitats, and the species is a generalist forager, preying on the most available forage fish near the colony.

  3. Foraging ecology of Caspian Terns in the Columbia River Estuary, USA

    USGS Publications Warehouse

    Lyons, Donald E.; Roby, D.D.; Collis, K.

    2005-01-01

    Comparisons were made of the foraging ecology of Caspian Terns (Sterna caspia) nesting on two islands in the Columbia River estuary using radio telemetry and observations of prey fed to chicks and mates at each colony. Early in the chick-rearing period, radio-tagged terns nesting at Rice Island (river km 34) foraged mostly in the freshwater zone of the estuary close to the colony, while terns nesting on East Sand Island (river km 8) foraged in the marine or estuarine mixing zones close to that colony. Late in the chick-rearing period, Rice Island terns moved more of their foraging to the two zones lower in the estuary, while East Sand Island terns continued to forage in these areas. Tern diets at each colony corresponded to the primary foraging zone (freshwater vs. marine/ mixing) of radio-tagged individuals: Early in chick-rearing, Rice Island terns relied heavily on juvenile salmonids (Oncorhynchus spp., 71% of identified prey), but this declined late in chick-rearing (46%). East Sand Island terns relied less on salmonids (42% and 16%, early and late in chick-rearing), and instead utilized marine fishes such as Anchovy (Engraulis mordax) and Herring (Clupea pallasi). Throughout chick-rearing, Rice Island terns foraged farther from their colony (median distance: 12.3 km during early chick-rearing and 16.9 km during late chick-rearing) than did East Sand Island terns (9.6 and 7.7 km, respectively). The study leads to the conclusion that Caspian Terns are generalist foragers and make use of the most proximate available forage fish resources when raising young.

  4. Factors affecting chick provisioning by Caspian Terns nesting in the Columbia River estuary

    USGS Publications Warehouse

    Anderson, Scott K.; Roby, D.D.; Lyons, Donald E.; Collis, K.

    2005-01-01

    We investigated factors affecting chick provisioning by radio-tagged Caspian Terns (Sterna caspia) nesting in a large colony on East Sand Island in the Columbia River estuary during 2001. Caspian Tern predation on juvenile salmonids (Oncorhynchus spp.) in the estuary prompted resource managers to relocate ca. 9,000 pairs of terns nesting on Rice Island (river km 34) to East Sand Island (river km 8), where terns were expected to consume fewer salmonids in favor of marine forage fishes. This study investigated factors influencing foraging success, diet composition, and overall reproductive success at the managed Caspian Tern colony. Our results indicated that daytime colony attendance by nesting terns averaged 64% and decreased throughout the chick-rearing period, while duration of foraging trips averaged 47 min and increased during the same period; these seasonal changes were more strongly related to date than chick age. Average meal delivery rates to 2-chick broods (0.88 meals h-1) were 2.6 times greater than to 1-chick broods (0.33 meals h-1). Parents delivered more juvenile salmonids to chicks during ebb tides than flood tides, but meal delivery rates to the nest remained constant, suggesting diet composition tracks relative availability of prey species. Foraging trips resulting in delivery of juvenile salmonids averaged 68% longer than foraging trips for schooling marine forage fishes, indicating higher availability of marine prey near the colony. High availability of marine forage fish in the Columbia River estuary during 2001 was apparently responsible for high colony attendance, short foraging trips, high chick meal delivery rates, and high nesting success of Caspian Terns on East Sand Island.

  5. Relationship of Caspian tern foraging ecology to nesting success in the Columbia River estuary, Oregon, USA

    USGS Publications Warehouse

    Anderson, Scott K.; Roby, D.D.; Lyons, Donald E.; Collis, K.

    2007-01-01

    The prevalence of juvenile salmonids (Oncorhynchus spp.) and marine forage fishes in the diet of Caspian terns (Hydroprogne caspia) nesting in the Columbia River estuary has been established, but the relationship between diet composition, foraging distribution, and productivity of these birds has received little attention. We used radio-telemetry and on-colony observations to relate changes in off-colony distribution to patterns of colony attendance, diet composition, and productivity of adult terns nesting on East Sand Island during two years of different river and prey conditions. Average distance from the East Sand Island colony (located in the marine zone of the estuary) was 38% (6.6 km) greater in 2000 compared to 2001, associated with lower availability of marine forage fish near East Sand Island and lower prevalence of marine prey in tern diets. Colony attendance was much lower (37.0% vs. 62.5% of daylight hours), average trip duration was 40% longer (38.9 min), and nesting success was much lower (0.57 young fledged pair-1 vs. 1.40 young fledged pair-1) in 2000 compared to 2001. Higher proportions of juvenile salmonids in the diet were associated with relatively high use of the freshwater zone of the estuary by radio-tagged terns, which occurred prior to chick-rearing and when out-migrating salmonid smolts were relatively abundant. Lower availability of marine prey in 2000 apparently limited Caspian tern nesting success by markedly reducing colony attendance and lengthening foraging trips by nesting terns, thereby increasing chick mortality rates from predation, exposure, and starvation. ?? 2007 Elsevier Ltd. All rights reserved.

  6. Estimating migratory connectivity of birds when re-encounter probabilities are heterogeneous

    USGS Publications Warehouse

    Cohen, Emily B.; Hostelter, Jeffrey A.; Royle, J. Andrew; Marra, Peter P.

    2014-01-01

    Understanding the biology and conducting effective conservation of migratory species requires an understanding of migratory connectivity – the geographic linkages of populations between stages of the annual cycle. Unfortunately, for most species, we are lacking such information. The North American Bird Banding Laboratory (BBL) houses an extensive database of marking, recaptures and recoveries, and such data could provide migratory connectivity information for many species. To date, however, few species have been analyzed for migratory connectivity largely because heterogeneous re-encounter probabilities make interpretation problematic. We accounted for regional variation in re-encounter probabilities by borrowing information across species and by using effort covariates on recapture and recovery probabilities in a multistate capture–recapture and recovery model. The effort covariates were derived from recaptures and recoveries of species within the same regions. We estimated the migratory connectivity for three tern species breeding in North America and over-wintering in the tropics, common (Sterna hirundo), roseate (Sterna dougallii), and Caspian terns (Hydroprogne caspia). For western breeding terns, model-derived estimates of migratory connectivity differed considerably from those derived directly from the proportions of re-encounters. Conversely, for eastern breeding terns, estimates were merely refined by the inclusion of re-encounter probabilities. In general, eastern breeding terns were strongly connected to eastern South America, and western breeding terns were strongly linked to the more western parts of the nonbreeding range under both models. Through simulation, we found this approach is likely useful for many species in the BBL database, although precision improved with higher re-encounter probabilities and stronger migratory connectivity. We describe an approach to deal with the inherent biases in BBL banding and re-encounter data to demonstrate

  7. Cost-effective management alternatives for Snake River Chinook salmon: a biological-economic synthesis.

    PubMed

    Halsing, David L; Moore, Michael R

    2008-04-01

    The mandate to increase endangered salmon populations in the Columbia River Basin of North America has created a complex, controversial resource-management issue. We constructed an integrated assessment model as a tool for analyzing biological-economic trade-offs in recovery of Snake River spring- and summer-run chinook salmon (Oncorhynchus tshawytscha). We merged 3 frameworks: a salmon-passage model to predict migration and survival of smolts; an age-structured matrix model to predict long-term population growth rates of salmon stocks; and a cost-effectiveness analysis to determine a set of least-cost management alternatives for achieving particular population growth rates. We assessed 6 individual salmon-management measures and 76 management alternatives composed of one or more measures. To reflect uncertainty, results were derived for different assumptions of effectiveness of smolt transport around dams. Removal of an estuarine predator, the Caspian Tern (Sterna caspia), was cost-effective and generally increased long-term population growth rates regardless of transport effectiveness. Elimination of adult salmon harvest had a similar effect over a range of its cost estimates. The specific management alternatives in the cost-effective set depended on assumptions about transport effectiveness. On the basis of recent estimates of smolt transport effectiveness, alternatives that discontinued transportation or breached dams were prevalent in the cost-effective set, whereas alternatives that maximized transportation dominated if transport effectiveness was relatively high. More generally, the analysis eliminated 80-90% of management alternatives from the cost-effective set. Application of our results to salmon management is limited by data availability and model assumptions, but these limitations can help guide research that addresses critical uncertainties and information. Our results thus demonstrate that linking biology and economics through integrated models can

  8. Faunal assemblages of the mussel Mytilus galloprovincialis in and around Alsancak Harbour (Izmir Bay, eastern Mediterranean) with special emphasis on alien species

    NASA Astrophysics Data System (ADS)

    Çinar, Melih Ertan; Katağan, Tuncer; Koçak, Ferah; Öztürk, Bilal; Ergen, Zeki; Kocatas, Ahmet; Önen, Mesut; Kirkim, Fevzi; Bakir, Kerem; Kurt, Güley; Dağli, Ertan; Açik, Sermin; Doğan, Alper; Özcan, Tahir

    The faunal assemblages of the mussel Mytilus galloprovincialis were examined seasonally at four stations located in and around Alsancak Harbour between January and September 2004. A total of 155 species belonging to 14 systematic groups were found in the assemblages, of which Polychaeta had the highest number of species and individuals. The assemblages were mainly composed of species tolerant to pollution. The number of individuals (maximum 209,000 ind m - 2 ) and biomass (maximum 24,563 g m - 2 ) of the assemblage were generally higher at the stations located in the harbours, whereas the station not located in the harbours had the highest number of species and diversity index values (maximum 4.19). The mussel faunal assemblages differed mainly according to seasons and locations (ANOSIM test), but seasonal samples collected at each station constituted separate groups in the MDS plot, which are moderately correlated with a combination of environmental variables such as temperature, the concentrations of total nitrogen and phosphate phosphorus ( ρr = 0.46, BIOENV test). The environmental conditions at each station, the structure of substratum to which the mussel was attached and the biotic interactions among the associated faunal components seemed to be main factors influencing the faunal assemblages of the mussel in the area. The combined effect of season and location significantly changed the community parameters such as the number of species and individuals, and the values of diversity, evenness and biomass (two-way ANOVA test). The factors significantly influencing these community parameters were the algae biomass on mussels, total nitrogen and dissolved oxygen concentrations. The density of the mussel was negatively correlated with the diversity and evenness values of samples. The mussel community included ten alien species: Pseudonereis anomala, Polydora cornuta, Streblospio gynobranchiata, Hydroides dianthus, Hydroides elegans, Maera hamigera, Stenothoe

  9. On the figures of the Earth

    NASA Astrophysics Data System (ADS)

    Tonn, R.; Zschau, J.

    The viscoelastic response of the Earth due to centrifugal force and the question as to whether or not an equilibrium figure exists have been investigated. In particular, we have studied the possible existence of a fossile equatorial bulge and the reason for the difference between the measured Geoid and the commonly adopted hydrostatic figure. By utilizing theoretical Love numbers a theory for the computation of the Earth's figure has been outlined. The investigation of a fluid Earth renders the computation of the hydrostatic figure (Hydroid) possible. We have shown that this figure cannot be determined unequivocally, because it is dependent on the unknown degree of relaxation in bulk. Consideration of the special case of a fluid Earth with unrelaxed bulk modulus yields a hydrostatic figure, which is in excellent agreement with published results from other authors. Using the same methods, but by using a Maxwell rheology for shear, and again assuming no relaxation of the bulk modulus, we have computed the spheroidal equipotential surface (Geoid) and the corresponding topographic surface (Topoid) as a function of time. The flattenings of the computed Geoid and Hydroid are equal, which implies that a fossile bulge cannot exist. However, the computed Geoid'S flattening proved to be different from the measured Geoid's flattening. This suggests that either internal dynamic forces or relaxation in bulk are important. In the latter case, the Earth could well be in hydrostatic equilibrium. The difference between the measured Geoid and the theoretical Geoid cannot be taken as an indication for the Earth's deviation from hydrostatic equilibrium. However, no further information about relaxation in bulk is available, thus leaving the consideration of relaxation in bulk a goal for future investigations. Finally, a new unequivocal criterion, which can be used to examine whether or not the Earth is in equilibrium, has been introduced. This requires that the shapes of the Topoid and

  10. The effectiveness of rotating brush devices for management of vessel hull fouling.

    PubMed

    Hopkins, Grant A; Forrest, Barrie M; Coutts, Ashley D M

    2010-07-01

    The present study tested two diver-operated rotating brush systems, coupled with suction and collection capabilities, to determine their efficacy in the management of vessel biofouling. Both rotating brush systems proved effective (> 80%) in removing low-to-moderate levels of fouling from flat and curved experimental surfaces (Perspex plates). However, performance was generally poorer at removing more advanced levels of fouling. In particular, mature calcareous organisms were relatively resistant to the rotating brushes, with a high proportion (up to 50%) remaining on plates following treatment. On average, > 95% of defouled material was collected and retained by both systems. The amount of lost material generally increased when treating curved plates with increasing biomass, whereas the material lost from flat plates was typically less and remained relatively constant throughout the trials. The majority (> 80%) of fouling not captured by the systems was crushed by the brushes (ie non-viable). However, a diverse range of viable organisms (eg barnacles and hydroids) was lost to the environment during the defouling trials. When defouling a vessel, unintentional detachment of fouling organisms is likely to be high through physical disturbance by divers operating the devices and by associated equipment (eg hoses). Furthermore, residual biosecurity risks are also likely to remain due to diver error, persistent fouling remaining on treated surfaces and the inaccessibility of niche areas to the brush systems. To address these limitations, further research into alternative treatment methods is required.

  11. Epibenthic and mobile species colonisation of a geotextile artificial surf reef on the south coast of England.

    PubMed

    Herbert, Roger J H; Collins, Ken; Mallinson, Jenny; Hall, Alice E; Pegg, Josephine; Ross, Kathryn; Clarke, Leo; Clements, Tom

    2017-01-01

    With increasing coastal infrastructure and use of novel materials there is a need to investigate the colonisation of assemblages associated with new structures, how these differ to natural and other artificial habitats and their potential impact on regional biodiversity. The colonisation of Europe's first artificial surf reef (ASR) was investigated at Boscombe on the south coast of England (2009-2014) and compared with assemblages on existing natural and artificial habitats. The ASR consists of geotextile bags filled with sand located 220m offshore on a sandy sea bed at a depth of 0-5m. Successional changes in epibiota were recorded annually on differently orientated surfaces and depths using SCUBA diving and photography. Mobile faunal assemblages were sampled using Baited Remote Underwater Video (BRUV). Distinct stages in colonisation were observed, commencing with bryozoans and green algae which were replaced by red algae, hydroids and ascidians, however there were significant differences in assemblage structure with depth and orientation. The reef is being utilised by migratory, spawning and juvenile life-history stages of fish and invertebrates. The number of non-native species was larger than on natural reefs and other artificial habitats and some occupied a significant proportion of the structure. The accumulation of 180 benthic and mobile taxa, recorded to date, appears to have arisen from a locally rich and mixed pool of native and non-native species. Provided no negative invasive impacts are detected on nearby protected reefs the creation of novel yet diverse habitats may be considered a beneficial outcome.

  12. The influence of macrofouling on the corrosion behaviour of API 5L X65 carbon steel.

    PubMed

    de Brito, Luciana V R; Coutinho, Ricardo; Cavalcanti, Eduardo H S; Benchimol, Marlene

    2007-01-01

    Seawater is a complex corrosive system, and biofouling is one of the factors that influences corrosion processes. The behaviour of corrosion associated with the development of macrofouling was investigated during the first 6 months of the successional process. Three treatments were compared: the 'Control' treatment (absence of macrofouling); 'Community' treatment, and 'Barnacle' treatment, where other macroorganisms were excluded. In the Community treatment, the dominant organisms were filamentous macroalgae (23.73%), barnacles (17.51%), hydroids (16.96%) and encrusting bryozoans (9.58%). In the Barnacle treatment, the cover varied between 39.38% and 62.50%. The corrosion potential ranged from -665.75 to -517.50 mV(Ag/AgC l((KCl))) and could not be associated with fouling development. The highest corrosion rate in the control suggests that macrofouling provides a protection against mass loss. The highest percentage of localised attacks was found in the Community treatment. This may indicate that not only barnacles, but also other organisms induce localised corrosion.

  13. Macrofouling control in nuclear power plants

    SciTech Connect

    Ekis, E.W. Jr.; Keoplin-Gall, S.M.; McCarthy, R.E.

    1991-11-01

    Macrofouling of cooling-water systems is one of the more significant and costly problems encountered in the nuclear power industry. Both marine and freshwater macroinvertebrates can be responsible for losses in plant availability because of plugged intakes and heat transfer equipment. There is a greater diversity of macrofouling organisms in marine waters than in fresh waters. Marine macrofouling organisms include barnacles, mollusks, bryozoans, and hydroids. Barnacles are crustaceans with feathery appendages, which allow them to attach to a variety of surfaces. They are a major cause of severe macrofouling because they can remain attached even after death. The major freshwater macrofouling organisms include the Asiatic Clam (Corbicula fluminea) and the newest freshwater macrofouler, the Zebra Mussel (Dreissena polymorpha). The introduction of the Zebra Mussel into the Great Lakes has created economic and ecological problems that will not easily be solved. The threat of intercontinental dispersal of the Zebra Mussel in America is serious. Research programs have been initiated around the country to develop control methods for this macrofouling problem. The various control methodologies can be classified in the following categories: biological, chemical, physical, and mechanical. Laboratory experiments were performed to evaluate the efficacy of Actibrom against mature Zebra Mussels.

  14. Polychaetes of an artificial reef in the central mediterranean sea

    NASA Astrophysics Data System (ADS)

    Gravina, M. F.; Ardizzone, G. D.; Belluscio, A.

    1989-02-01

    The development of a polychaete community over five years on a man-made reef was analyzed. The reef was composed of 280 concrete blocks (2 × 2 × 2 m) and located in the Tyrrhenian Sea (Italy) 1.5 miles offshore and 12-14 m deep. Sixty-three species were collected—serpulids, nereids and cirratulids being the most abundant families. Ordination by Principal Components Analysis (PCA) technique showed three main stages in the colonization process: a pioneer phase, when mainly serpulids ( Pomatoceros triqueter, P. lamarckii, Hydroides pseuduncinata) occurred; a second phase, characterized by mussel ( Mytilus galloprovincialis) dominance and a more differentiated community structure with a lot of new species especially recurring on hard bottom ( Serpula concharum, H. dianthus, Ceratonereis costae); and a third phase, with an alteration of the substratum through soft deposits and the polychaete community characterized by also the occurrence of soft bottom species ( Heteromastus filiformis, Polydora ciliata, Dorvillea rubrovittata). From the trophic point of view, the structure of the community changed from dominance by filter feeders (97%) to a more differentiated situation with abundant detritic feeders ( c. 20%). The rates of immigration and extinction and the colonization curve showed that an actual stable steady-state was not reached.

  15. Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration

    PubMed Central

    Leclère, Lucas; Röttinger, Eric

    2017-01-01

    The ability to perform muscle contractions is one of the most important and distinctive features of eumetazoans. As the sister group to bilaterians, cnidarians (sea anemones, corals, jellyfish, and hydroids) hold an informative phylogenetic position for understanding muscle evolution. Here, we review current knowledge on muscle function, diversity, development, regeneration and evolution in cnidarians. Cnidarian muscles are involved in various activities, such as feeding, escape, locomotion and defense, in close association with the nervous system. This variety is reflected in the large diversity of muscle organizations found in Cnidaria. Smooth epithelial muscle is thought to be the most common type, and is inferred to be the ancestral muscle type for Cnidaria, while striated muscle fibers and non-epithelial myocytes would have been convergently acquired within Cnidaria. Current knowledge of cnidarian muscle development and its regeneration is limited. While orthologs of myogenic regulatory factors such as MyoD have yet to be found in cnidarian genomes, striated muscle formation potentially involves well-conserved myogenic genes, such as twist and mef2. Although satellite cells have yet to be identified in cnidarians, muscle plasticity (e.g., de- and re-differentiation, fiber repolarization) in a regenerative context and its potential role during regeneration has started to be addressed in a few cnidarian systems. The development of novel tools to study those organisms has created new opportunities to investigate in depth the development and regeneration of cnidarian muscle cells and how they contribute to the regenerative process. PMID:28168188

  16. Competitive equivalence maintains persistent inter-clonal boundaries.

    PubMed

    Ferrell, David L

    2005-01-01

    Clear boundaries often separate adjacent conspecific competitors. These boundaries may reflect bordering animal territories or regions of inter-organism contact in mobile and non-mobile organisms, respectively. Sessile, clonal organisms often form persistent inter-clonal boundaries despite great variation in competitive ability among genotypes within a population. I show that neighboring clones in the sea anemone Anthopleura elegantissima and three species of the marine hydroid genus Hydractinia are more evenly matched in terms of competitive ability than expected by chance. Hypotheses of genetic relatedness or similar environmental regime shared by neighboring clones are inconsistent with the observed similarities between adjacent competitors in one or both taxa. Instead, inter-clonal borders evidently persist as standoffs between evenly matched competitors. Large differences in competitive ability between bordering clones were rarely observed, suggesting that dominant clones quickly displace or eliminate others in competitive mismatches. This ecological parallel between taxa (i.e., competitive equivalence) exists despite several fundamental differences (e.g., geographical distribution, habitat, body size, longevity), suggesting that competitive equivalence may be a widespread determinant of boundary persistence between adjacent competitors.

  17. Structural but not functional conservation of an immune molecule: a tachylectin-like gene in Hydractinia.

    PubMed

    Mali, Brahim; Soza-Ried, Jorge; Frohme, Marcus; Frank, Uri

    2006-01-01

    Tachylectin-related proteins are a recently characterized group of pattern recognition molecules, functioning in the innate immunity of various animals, from the ancient sponges to vertebrates. Tachylectins are characterized by six internal tandem repeats forming beta-propeller domains. We have identified and characterized a tachylectin-related gene in the colonial marine hydroid, Hydractinia echinata. The predicted gene product, termed CTRN, contained an N-terminal signal peptide and had a well-conserved tachylectin-like structure. RT-PCR analyses revealed only post-metamorphic expression while no mRNA was detected during embryonic development or in planula larvae. Exposure of colonies to LPS under conditions known to activate an immune response in Hydractinia did not result in upregulation of the gene. In situ hybridization analysis of metamorphosed animals detected CTRN transcripts only in a small subpopulation of neurons and their precursor cells, localized in a ring-like structure around the mouth of polyps. The same ring-like structure of CTRN expressing neurons was also observed in young polyp buds, predicting the position of the future mouth. This type of expression pattern can hardly be attributed to an immune-relevant gene. Thus, despite high structural similarity to tachylectins, this cnidarian member of this group seems to be an exception to all other tachylectins identified so far as it seems to have no function in cnidarian innate immunity.

  18. Correlation between pigmentation and larval settlement deterrence by Pseudoalteromonas sp. sf57.

    PubMed

    Huang, Yi-Li; Li, Mu; Yu, Zhiliang; Qian, Pei-Yuan

    2011-03-01

    The red-pigmented marine bacterium Pseudoalteromonas sp. sf57 forms a biofilm that deters larval settlement of the tube-building polychaete Hydroides elegans. To investigate the correlation between pigmentation and larval settlement deterrence, mutants of sf57 with deficient or altered pigmentation were generated by transposon mutagenesis. Five groups of pigmented mutants were obtained, viz. white, yellow, pink, dark red, and white-to-red. The white mutant WM1, which exhibited a substantial increase in bacterial density in the biofilm, became inductive to larval settlement. The other mutants that showed a lesser increase in bacterial density in their biofilms either retained their deterrence or induced higher larval settlement rates, but did not become inductive strains. Analysis of the disrupted genes in these mutants suggests that the type II secretion pathway, the LysR transcriptional regulator, NAD(P)-binding proteins, exonuclease, pyruvate metabolism, flagella assembly, and cell membrane processes may play a role in the regulation of pigmentation in sf57.

  19. Amplified recruitment pressure of biofouling organisms in commercial salmon farms: potential causes and implications for farm management.

    PubMed

    Bloecher, Nina; Floerl, Oliver; Sunde, Leif Magne

    2015-01-01

    The development of biofouling on finfish aquaculture farms presents challenges for the industry, but the factors underlying nuisance growths are still not well understood. Artificial settlement surfaces were used to examine two possible explanations for high rates of biofouling in Norwegian salmon farms: (1) increased propagule release during net cleaning operations, resulting in elevated recruitment rates; and (2) potential reservoir effects of farm surfaces. The presence of salmon farms was associated with consistently and substantially (up to 49-fold) elevated recruitment rates. Temporal patterns of recruitment were not driven by net cleaning. Resident populations of biofouling organisms were encountered on all submerged farm surfaces. Calculations indicate that a resident population of the hydroid Ectopleura larynx, a major biofouling species, could release between 0.3 × 10(9) and 4.7 × 10(9) larvae per farm annually. Such resident populations could form propagule reservoirs and be one explanation for the elevated recruitment pressure at salmon farms.

  20. Effects of metals and sediment particle size on the species composition of the epifauna of Pinna bicolor near a lead smelter, Spencer Gulf, South Australia

    NASA Astrophysics Data System (ADS)

    Ward, Trevor J.; Young, Peter C.

    1984-01-01

    Pinna bicolor (Mollusca: Pelecypoda) were transplanted between four sites near a lead smelter. The species composition of their epifauna (sessile and mobile) was examined in relation to characteristics of both sediments and seston at the sites. Seventy-two taxa were distinguished in the epifaunal community. Substantial differences were found in the short-term sensitivity of some of the species to concentrations of Cd, Pb and Zn in sediments and to sediment particle size. The short-term sensitivity of many species to metals or sediment particle size explained their long-term distribution pattern. Twenty-three taxa were identified as significantly characterizing the faunal differences. Of these, eleven (four molluscs, four bryozoans, two barnacles and one ascidian) were affected by both sediment metal concentration and particle size, and eight (four molluscs, one bryozoan, one polychaete, one hydroid and one barnacle) were affected by metal contamination but not particle size. Of all fauna examined, the Bryozoa were the most metal-sensitive. Four species, Smittina raigii (Bryozoa), Galeolaria sp. 1 (Polychaeta), Epopella simplex (Cirripedia) and Monia ione (Pelecypoda) were identified by their short- and long-term sensitivity to metal contamination, and absence of sensitivity to sediment particle size, as suitable species for monitoring the effects of metal contamination on the epifauna. The implications of the results for toxicity-testing are discussed.

  1. The Suez Canal as a habitat and pathway for marine algae and seagrasses

    NASA Astrophysics Data System (ADS)

    Aleem, A. A.

    The Suez Canal supports a diversified benthic algal flora; 133 species of benthic algae are now known from the Canal, as compared with only 24 in 1924. The vertical and horizontal distribution of algae is considered in relation to hydrographic factors. The algae display zonation and 3-4 algal belts are distinguished on the Canal banks on buoys and pier supports. Associated fauna include Balanus amphitrite and Brachidontes variabilis, together with various hydroids, sponges, ascidians, asteroids, ophiuroids and crustaceans. Merceriella enigmatica thrives well in brackish water habitats. The algal flora in the Bitter Lakes resembles that in the Red Sea. The number of Red Sea species decreases from Suez to Port Said in the littoral zone. On the other hand, bottom algae predominantly belong to Red Sea flora. Thirty of the species of algae found belong to the Indo-Pacific flora; half of these are new records to the Canal. Several of these Indo-Pacific algae have recently become established in the Eastern Mediterranean, whereas only two of the Mediterranean macro-algal flora (viz. Caulerpa prolifera and Halopteris scoparia) have been found in the Gulf of Suez. Two seagrasses, Halopia ovalis and Thalassia hemprichii, are recorded for the first time in the Canal. Only Halophila stipulacea has found its way into the Mediterranean via the Suez Canal, but none of the Mediterranean seagrasses is found either in the Canal or in the Red Sea.

  2. Caprellidae (Crustacea: Peracarida: Amphipoda) from the Red Sea and Suez Canal, with the redescription of Metaprotella africana and Paradeutella multispinosa.

    PubMed

    Zeina, Amr F; Guerra-García, José M

    2016-04-06

    The Caprellidae from the Red Sea are reviewed based on the literature data and new collections from the Hurghada coasts. So far, only six valid species has been reported from the Red Sea and Suez Canal: Caprella equilibra Say, 1818, Hemiaegina minuta Mayer, 1890, Metaprotella africana Mayer, 1903, Paracaprella pusilla Mayer, 1890 and Paradeutella multispinosa Schellenberg, 1928 and Pseudocaprellina pambanensis Sundara Raj, 1927. The type material of M. africana (deposited in the Muséum nacional d'Histoire naturelle, Paris) and Paradeutella multispinosa (deposited in the Museum für Naturkunde, Berlin) are redescribed and illustrated in detail. P. pambanensis and H. minuta were the most abundant species in the collections along the northern coast. Most of the sampling effort has been focused on algae from shallow waters; additional substrates such as sediments, hydroids and coral rubble, especially from areas deeper than 15 meters should be explored. The number of caprellid species in the Red Sea is low compared to adjacent waters, as the Mediterranean Sea. However, further research and more extensive caprellid collections should be conducted along the coasts of Saudi Arabia, Yemen, Sudan and Eritrea, which are still unexplored.

  3. Morphologie und Ultrastruktur der Koralle Cornularia cornucopiae (Anthozoa, Octocorallia)

    NASA Astrophysics Data System (ADS)

    Benke, H.; Hündgen, M.

    1984-03-01

    Cornularia cornucopiae is a colonial coral whose polyps arise singly from stolons. In contrast with other octocrallia C. cornucopiae lacks calcareous spicules. Therefore, tissue preparation for electron microscopic investigations can be performed. The presence of a calyx such as the theca of hydroids, in which the polyps may be completely retracted, is conspicuous. The calyx consists of three layers. The structure of the basal layer suggests massive collagen. The body wall is connected with the calyx by living desmocytes. The histology of the oral disc and the actinopharynx is identical. The ventral side of the polyps bears the siphonoglyph. Below the pharynx the inner edges of the mesenteries are free and form the mesenterial filaments. The two ventral mesenteries differ from the others; the one is long and exhibits a large and heavily flagellated filament, the other is short and lacks a filament. The muscular system is represented by gastrodermal circular fibres in the body wall and by radial and longitudinal fibres in the septa; a large septal retractor muscle is missing.

  4. Phylogenetic analysis with multiple markers indicates repeated loss of the adult medusa stage in Campanulariidae (Hydrozoa, Cnidaria).

    PubMed

    Govindarajan, Annette F; Boero, Ferdinando; Halanych, Kenneth M

    2006-03-01

    The Campanulariidae is a group of leptomedusan hydroids (Hydrozoa, Cnidaria) that exhibit a diverse array of life cycles ranging from species with a free medusa stage to those with a reduced or absent medusa stage. Perhaps the best-known member of the taxon is Obelia which is often used as a textbook model of hydrozoan life history. However, Obelia medusae have several unique features leading to a hypothesis that Obelia arose, in a saltational fashion, from an ancestor that lacked a medusa, possibly representing an example of a rare evolutionary reversal. To address the evolution of adult sexual stages in Campanulariidae, a molecular phylogenetic approach was employed using two nuclear (18S rDNA and calmodulin) and two mitochondrial (16S rDNA and cytochrome c oxidase subunit I) genes. Prior to the main analysis, we conducted a preliminary analysis of leptomedusan taxa which suggests that Campanulariidae as presently considered needs to be redefined. Campanulariid analyses are consistent with morphological understanding in that three major clades are recovered. However, several recognized genera are not monophyletic calling into question some "diagnostic" features. Furthermore, ancestral states were reconstructed using parsimony, and a sensitivity analysis was conducted to investigate possible evolutionary transitions in life-history stages. The results indicate that life-cycle transitions have occurred multiple times, and that Obelia might be derived from an ancestor with Clytia-like features.

  5. Behavior of Settling Marine Larvae in Flow

    NASA Astrophysics Data System (ADS)

    Hernandez, J.; Koehl, M. A.

    2012-12-01

    Many bottom-dwelling marine animals produce microscopic larvae that are dispersed by ambient water currents. These larvae can only recruit to habitats on which they have landed if they can resist being washed away by ambient water flow. We found that larvae on marine surfaces do not experience steady water flow, but rather are exposed to brief pulses of water movement as turbulent eddies sweep across them. We made video recordings of larvae of the tube worm, Hydroides elegans, (important members of the community of organisms growing on docks and ships) on surfaces subjected to measured realistic flow pulses to study factors that might affect their dislodgement from surfaces in nature. We found that the response of a larva of H. elegans to a realistic pulse of water flow depended on its behavior at the time of the pulse and on its recent history of exposure to flow pulses, and that stationary larvae were less likely than locomoting larvae to be blown away when hit by the first pulse of water flow.; ;

  6. The ghost of fouling communities past: the effect of original community on subsequent recruitment.

    PubMed

    Ralston, Emily A; Swain, Geoffrey W

    2014-01-01

    Biofouling on ships has been linked to the spread of invasive species, which has been identified as one of the current primary threats to the environment. Previous research on antifouling coatings suggested that the quantity of fouling, as well as community composition, on biocidal coatings was modified by prior fouling settlement. The experiment reported in this paper was designed to determine how preconditioning affected the rate and composition of subsequent fouling on transplanted silicone coatings. A series of 10 × 20 cm panels coated with Intersleek 700 or DC3140 were placed at three locations in Florida (Ponce Inlet, Sebastian Inlet, and Port of Miami), which were characterized by distinct fouling communities. Panels were immersed for four months, cleaned, and reciprocally transplanted among the three sites. Fouling community composition and coverage were characterized at bimonthly intervals both before and after transplantation. The original fouling community affected the subsequent fouling composition and recolonization by tunicates, sea anemones, barnacles, sponges, hydroids, and arborescent bryozoans. The community-level effects were short-term, lasting 2-4 months, but specific responses lasted up to 14 months post-transplant.

  7. Effect of halogenated fluorescent compounds on bioluminescent reactions.

    PubMed

    Kirillova, Tamara N; Gerasimova, Marina A; Nemtseva, Elena V; Kudryasheva, Nadezhda S

    2011-04-01

    The paper investigates an application of luminescent bioassays to monitor the toxicity of organic halides. Effects of xanthene dyes (fluorescein, eosin Y, and erythrosin B), used as model compounds, on bioluminescent reactions of firefly Luciola mingrelica, marine bacteria Photobacterium leiognathi, and hydroid polyp Obelia longissima were studied. Dependence of bioluminescence quenching constants on the atomic weight of halogen substituents in dye molecules was demonstrated. Bacterial bioluminescence was shown to be most sensitive to heavy halogen atoms involved in molecular structure; hence, it is suitable for construction of sensors to monitor toxicity of halogenated compounds. Mechanisms of bioluminescence quenching--energy transfer processes, collisional interactions, and enzyme-dye binding--were considered. Changes of bioluminescence (BL) spectra in the presence of the dyes were analyzed. Interactions of the dyes with enzymes were studied using fluorescence characteristics of the dyes in steady-state and time-resolved experiments. The dependences of fluorescence anisotropy of enzyme-bound dyes, the average fluorescence lifetime, and the number of exponential components in fluorescence decay on the atomic weight of halogen substituents were demonstrated. The results are discussed in terms of "dark effect of heavy halogen atom" in the process of enzyme-dye binding; hydrophobic interactions were assumed to be responsible for the effect.

  8. Synergistic toxic effects of zinc pyrithione and copper to three marine species: Implications on setting appropriate water quality criteria.

    PubMed

    Bao, Vivien W W; Leung, Kenneth M Y; Kwok, Kevin W H; Zhang, Amy Q; Lui, Gilbert C S

    2008-01-01

    Zinc pyrithione (ZnPT) is widely applied in conjunction with copper (Cu) in antifouling paints as a substitute for tributyltin. The combined effects of ZnPT and Cu on marine organisms, however, have not been fully investigated. This study examined the toxicities of ZnPT alone and in combination with Cu to the diatom Thalassiosira pseudonana, polychaete larvae Hydroides elegans and amphipod Elasmopus rapax. Importantly, ZnPT and Cu resulted in a strong synergistic effect with isobologram interaction parameter lambda>1 for all test species. The combined toxicity of ZnPT and Cu was successfully modelled using the non-parametric response surface and its contour. Such synergistic effects may be partly due to the formation of copper pyrithione. It is, therefore, inadequate to assess the ecological risk of ZnPT to marine organisms solely based on the toxicity data generated from the biocide alone. To better protect precious marine resources, it is advocated to develop appropriate water quality criteria for ZnPT with the consideration of its compelling synergistic effects with Cu at environmentally realistic concentrations.

  9. Description, systematics and ecology of a new tanaidacean (Crustacea, Peracarida) species from mediterranean fish farms

    NASA Astrophysics Data System (ADS)

    Esquete, P.; Fernandez-Gonzalez, V.

    2017-01-01

    An undescribed species of tanaidacean belonging to the genus Hexapleomera, tribe Pancolini, Hexapleomera bultidactyla sp. nov. was found in fouling community samples from off-coast fish farms cages in the western Mediterranean Sea. The species can be distinguished from other Hexapleomera species by the presence of a ventral apophysis on the dactylus of the chela in males. Other diagnostic characters (in combination) include a male antennule with five aesthetascs, the female with three, the maxillule palp with four terminal setae and maxilliped basis and coxa each with two setae; the male fixed finger with four ventral setae and proximal apophysis, the female chela fixed finger with a proximal triangular apophysis, an apophysis on the coxa of pereopod 1, a pleopod 3 basis with three outer setae, and an uropod of four segments. Although several substrata were investigated, the species was most abundant where the turf formed by Ceramiaceae algae and the hydroid Aglaophenia sp. was dominant. An updated identification key to all the species of Hexapleomera is provided.

  10. Proteomic response of marine invertebrate larvae to ocean acidification and hypoxia during metamorphosis and calcification.

    PubMed

    Mukherjee, Joy; Wong, Kelvin K W; Chandramouli, Kondethimmanahalli H; Qian, Pei-Yuan; Leung, Priscilla T Y; Wu, Rudolf S S; Thiyagarajan, Vengatesen

    2013-12-15

    Calcifying marine invertebrates with complex life cycles are particularly at risk to climate changes as they undergo an abrupt ontogenetic shift during larval metamorphosis. Although our understanding of the larval response to climate changes is rapidly advancing, the proteome plasticity involved in a compensatory response to climate change is still unknown. In this study, we investigated the proteomic response of metamorphosing larvae of the tubeworm Hydroides elegans, challenged with two climate change stressors, ocean acidification (OA; pH 7.6) and hypoxia (HYP; 2.8 mg O2 l(-1)), and with both combined. Using a two-dimensional gel electrophoresis (2-DE)-based approach coupled with mass spectrometry, we found that climate change stressors did not affect metamorphosis except under OA, but altered the larval proteome and phosphorylation status. Metabolism and various stress and calcification-related proteins were downregulated in response to OA. In OA and HYP combined, HYP restored the expression of the calcification-related proteins to the control levels. We speculate that mild HYP stress could compensate for the negative effects of OA. This study also discusses the potential functions of selected proteins that might play important roles in larval acclimation and adaption to climate change.

  11. Dietary analysis of the marine Amphipoda (Crustacea: Peracarida) from the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Guerra-García, J. M.; Tierno de Figueroa, J. M.; Navarro-Barranco, C.; Ros, M.; Sánchez-Moyano, J. E.; Moreira, J.

    2014-01-01

    The gut contents of 2982 specimens of 33 amphipod families, 71 genera and 149 species were examined, representing a high percentage of amphipod diversity in the Iberian Peninsula. Material was collected mainly from sediments, algae and hydroids along the whole coast of the Iberian Peninsula from 1989 to 2011. Although detritus was the dominant food item in the majority of amphipods, gammarideans also included carnivorous (mainly feeding on crustaceans) and herbivorous species (feeding on macroalgal tissues). Our study revealed that general assignment of a type of diet for a whole family is not always adequate. Some families showed a consistent pattern in most of the studied species (Corophiidae, Pontoporeiidae = detritivorous; Oedicerotidae, Phoxocephalidae, Stenothoidae = carnivorous; Ampithoidae = primarily herbivorous on macroalgae), but others included species with totally different feeding strategies. In general terms, detritivorous families were characterized by a stronger mandibular molar, while in carnivorous taxa this feature was less developed or reduced. The percentage of macroalgae in the digestive contents was associated in most cases with a reduction or loss of the mandibular palp. It seems that high trophic diversity in amphipods is a generalized trait along different ecosystems in all latitudes, and could be related to the ecological success of this group in marine benthic communities.

  12. Temporal and spatial variation in the fouling of silicone coatings in Pearl Harbor, Hawaii.

    PubMed

    Holm, E R; Nedved, B T; Phillips, N; Deangelis, K L; Hadfield, M G; Smith, C M

    2000-01-01

    An antifouling or foul-release coating cannot be globally effective if it does not perform well in a range of environmental conditions, against a diversity of fouling organisms. From 1996 to 1998, the field test sites participating in the United States Navy's Office of Naval Research 6.2 Biofouling program examined global variation in the performance of 3 silicone foul-release coatings, viz. GE RTV11, Dow Corning RTV 3140, and Intersleek (International Coatings Ltd), together with a control anticorrosive coating (Ameron Protective Coatings F-150 series). At the University of Hawaii's test site in Pearl Harbor, significant differences were observed among the coatings in the rate of accumulation of fouling. The control coating failed rapidly; after 180-220 d immersion a community dominated by molluscs and sponges developed that persisted for the remainder of the experiment. Fouling of the GE and Dow Corning silicone coatings was slower, but eventually reached a similar community structure and coverage as the control coatings. The Intersleek coating remained lightly fouled throughout the experiment. Spatial variation in the structure of the community fouling the coatings was observed, but not in the extent of fouling. The rate of accumulation of fouling reflected differences among the coatings in adhesion of the tubeworm Hydroides elegans. The surface properties of these coatings may have affected the rate of fouling and the structure of the fouling community through their influence on larval settlement and subsequent interactions with other residents, predators, and the physical environment.

  13. Effects of bottom fishing on the benthic megafauna of Georges Bank

    USGS Publications Warehouse

    Collie, J.S.; Escanero, G.A.; Valentine, P.C.

    1997-01-01

    This study addresses ongoing concerns ever the effects of mobile fishing gear on benthic communities. Using side-scan sonar, bottom photographs and fishing records, we identified a set of disturbed and undisturbed sites on the gravel pavement area of northern Georges Bank in the northwest Atlantic. Replicate samples of the megofauna were collected with a 1 m Naturalists' dredge on 2 cruises in 1994. Compared with the disturbed sites, the undisturbed sites had higher numbers of organisms, biomass, species richness and species diversity; evenness was higher at the disturbed sites. Undisturbed sites were characterized by an abundance of bushy epifaunal taxa (bryozoans, hydroids, worm tubes) that provide a complex habitat for shrimps, polychaetes, brittle stars, mussels and small fish. Disturbed sites were dominated by larger, hard-shelled molluscs, and scavenging crabs and echinoderms. Many of the megafaunal species in our samples have also been identified in stomach contents of demersal fish on Georges Bank; the abundances of at feast some of these species were reduced at the disturbed sites.

  14. Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration.

    PubMed

    Leclère, Lucas; Röttinger, Eric

    2016-01-01

    The ability to perform muscle contractions is one of the most important and distinctive features of eumetazoans. As the sister group to bilaterians, cnidarians (sea anemones, corals, jellyfish, and hydroids) hold an informative phylogenetic position for understanding muscle evolution. Here, we review current knowledge on muscle function, diversity, development, regeneration and evolution in cnidarians. Cnidarian muscles are involved in various activities, such as feeding, escape, locomotion and defense, in close association with the nervous system. This variety is reflected in the large diversity of muscle organizations found in Cnidaria. Smooth epithelial muscle is thought to be the most common type, and is inferred to be the ancestral muscle type for Cnidaria, while striated muscle fibers and non-epithelial myocytes would have been convergently acquired within Cnidaria. Current knowledge of cnidarian muscle development and its regeneration is limited. While orthologs of myogenic regulatory factors such as MyoD have yet to be found in cnidarian genomes, striated muscle formation potentially involves well-conserved myogenic genes, such as twist and mef2. Although satellite cells have yet to be identified in cnidarians, muscle plasticity (e.g., de- and re-differentiation, fiber repolarization) in a regenerative context and its potential role during regeneration has started to be addressed in a few cnidarian systems. The development of novel tools to study those organisms has created new opportunities to investigate in depth the development and regeneration of cnidarian muscle cells and how they contribute to the regenerative process.

  15. Epibenthic colonization of concrete and steel pilings in a cold-temperate embayment: a field experiment

    NASA Astrophysics Data System (ADS)

    Andersson, Mathias H.; Berggren, Matz; Wilhelmsson, Dan; Öhman, Marcus C.

    2009-09-01

    With large-scale development of offshore wind farms, vertical structures are becoming more common in open water areas. To examine how vertical structures of different materials may be colonized by epibenthic organisms, an experiment was carried out using steel and concrete pilings constructed to resemble those commonly used in wind farm constructions as well as in bridges, jetties and oil platforms. The early recruitment and succession of the epibenthic communities were sampled once a month for the first 5 months and then again after 1 year. Further, the fish assemblages associated with the pillars were sampled and compared to natural areas. The main epibenthic species groups, in terms of coverage, differed between the two materials at five out of six sampling occasions. Dominant organisms on steel pillars were the barnacle Balanus improvisus, the calcareous tubeworm Pomatoceros triqueter and the tunicate Ciona intestinalis. On the concrete pillars, the hydroid Laomedea sp. and the tunicates Corella parallelogramma and Ascidiella spp. dominated. However, there was no different in coverage at different heights on the pillars or in biomass and species abundance at different directions (north-east or south-west) 5 months after submergence. Fish showed overall higher abundances and species numbers on the pillars (but no difference between steel and concrete) compared to the surrounding soft bottom habitats but not compared to natural vertical rock walls. Two species were attracted to the pillars, indicating a reef effect; Gobiusculus flavescens and Ctenolabrus rupestris. The bottom-dwelling gobies, Pomatoschistus spp., did not show such preferences.

  16. A Possible Role for Agglutinated Foraminifers in the Growth of Deep-Water Coral Bioherms

    NASA Astrophysics Data System (ADS)

    Messing, C. G.; Reed, J. K.; Brooke, S. D.

    2008-05-01

    Exploration of deep-water bioherms dominated by the scleractinian corals Lophelia pertusa and Enallopsammia profunda along the east coast of Florida in ~400-800 m depth reveals an often dense and rich assemblage of small (~1-30 mm) epifauna on dead coral branches, which is often dominated by agglutinated astrorhizacean foraminifers accompanied by thecate and athecate hydroids, sponges, stylasterids, anemones and barnacles. The dominant agglutinated foraminifer is an arborescent form up to 15 mm tall, consisting of a basal tube that gives rise to branchlets of successively decreasing diameter and thickly coated with fine-grained material including coccoliths and diatom frustules. The large numbers of foraminifers generate an enormous adhesive, sediment-trapping surface area and may represent an important accelerated route for sediment deposition and bioherm growth relative to baffling of suspended sediment particles by the coral branches themselves. These foraminifers also occur on still living coral, suggesting that they may either contribute to coral death or invade stressed colonies. They may thus be responsible for or contribute to the small percent of living corals observed in many of these habitats. Other epifauna appear to colonize after the coral has died.

  17. Charles Manning Child (1869-1954): the past, present, and future of metabolic signaling.

    PubMed

    Blackstone, Neil W

    2006-01-15

    Charles Manning Child's work focused on metabolic gradients and their influence on organismal development. Early in the 20th century, his work had considerable currency, but by the second half of the century he had become little more than a historical footnote. Yet today Child's ideas are once again topical. While there were issues of cause and effect that Child and his students were never able to address adequately, in hindsight the extent of his eclipse hardly seems warranted. In fact, the demise of Child's theories may have resulted from larger changes in the nature of biology in the early 20th century. Child frequently studied planarians, hydroids, and other animals that are capable of asexual, agametic reproduction, and his theories most clearly apply to such organisms. In contrast, Thomas Hunt Morgan, initially one of Child's competitors in studies of regeneration, later developed the field of transmission genetics based on fruit flies, which can only reproduce via gametes. Child's theories and model systems were largely casualties of the success of Morgan's mechanistic paradigm. Nevertheless, in modern biology metabolic gradients, recast in terms of redox signaling, have become central to understanding both normal and pathological development. (c) 2005 Wiley-Liss, Inc.

  18. Induction of Invertebrate Larval Settlement; Different Bacteria, Different Mechanisms?

    PubMed Central

    Freckelton, Marnie L.; Nedved, Brian T.; Hadfield, Michael G.

    2017-01-01

    Recruitment via settlement of pelagic larvae is critical for the persistence of benthic marine populations. For many benthic invertebrates, larval settlement occurs in response to surface microbial films. Larvae of the serpulid polychaete Hydroides elegans can be induced to settle by single bacterial species. Until now, only Pseudoalteromonas luteoviolacea had been subjected to detailed genetic and mechanistic studies. To determine if the complex structures, termed tailocins, derived from phage-tail gene assemblies and hypothesized to be the settlement cue in P. luteoviolacea were present in all inductive bacteria, genomic comparisons with inductive strains of Cellulophaga lytica, Bacillus aquimaris and Staphylococcus warneri were undertaken. They revealed that the gene assemblies for tailocins are lacking in these other bacteria. Negatively stained TEM images confirmed the absence of tailocins and revealed instead large numbers of extracellular vesicles in settlement-inductive fractions from all three bacteria. TEM imaging confirmed for C. lytica that the vesicles are budded from cell surfaces in a manner consistent with the production of outer membrane vesicles. Finding multiple bacteria settlement cues highlights the importance of further studies into the role of bacterial extracellular vesicles in eliciting settlement and metamorphosis of benthic marine larvae. PMID:28195220

  19. An empirical examination of consumer effects across twenty degrees of latitude.

    PubMed

    Lavender, James T; Dafforn, Katherine A; Bishop, Melanie J; Johnston, Emma L

    2017-09-01

    The strength and importance of consumer effects are predicted to increase toward low latitudes, but this hypothesis has rarely been tested using a spatially consistent methodology. In a consumer-exclusion experiment spanning twenty degrees of latitude along the east Australian coast, the magnitude of consumer effects on sub-tidal sessile assemblage composition was not greater at low than high latitudes. Across caged and control assemblages, Shannon's diversity, Pielou's evenness, and richness of functional groups decreased with increasing latitude, but the magnitude of consumer effects on these metrics did not display consistent latitudinal gradients. Instead, latitudinal gradients in consumer effects were apparent for individual functional groups. Solitary ascidians displayed the pattern consistent with predictions of greater direct effects of predators at low than high latitude. As consumers reduced the biomass of this and other competitive dominants, groups less prone to predation (e.g., hydroids, various groups of bryozoans) were able to take advantage of freed space in the presence of consumers and show increased abundances there. This large-scale empirical study demonstrates the complexity of species interactions, and the failure of assemblage-level metrics to adequately capture consumer effects over large spatial gradients. © 2017 by the Ecological Society of America.

  20. Weakening mechanisms of the serpulid tube in a high-CO2 world.

    PubMed

    Li, Chaoyi; Chan, Vera B S; He, Chong; Meng, Yuan; Yao, Haimin; Shih, Kaimin; Thiyagarajan, Vengatesen

    2014-12-16

    Many benthic marine organisms produce calcium carbonate (CaCO3) structures for mechanical protection through a biologically controlled calcification process. However, the oceans are becoming unfavorable for calcification because of the stress associated with ocean acidification (OA) and associated chemical changes such as declining saturation state of CaCO3 and decreasing seawater pH. This work studies the impacts of OA-driven decreased pH on the calcareous tubes produced by the serpulid tubeworm Hydroides elegans. Tubes grown under control and OA experimental conditions were measured for structural and mechanical properties, and their mechanical properties were further interpreted using finite element analysis (FEA). The near-future predicted pH value of 7.8 altered tube ultrastructure, volume, and density and decreased the mean tube hardness and elasticity by ∼ 80 and ∼ 70%, respectively. The crushing force required for breaking the tube was reduced by 64%. The FEA results demonstrated how a simulated predator attack may affect the structure with different structural and mechanical properties and consequently shift the stress development and distribution in the tubes, causing a more concentrated stress distribution and therefore leading to a lower ability to withstand attacks.

  1. Fenxiang biota: a new Early Ordovician shallow-water fauna with soft-part preservation from China.

    PubMed

    Balinski, Andrzej; Sun, Yuanlin

    Our perception of biodiversity in the geological past is incomplete and biased because most organisms did not have mineralized skeletons and therefore had little chance of fossilization. This especially refers to shallow-water marine environments, rarely represented by localities with exceptional preservation of fossil material (known as taphonomic windows or Konservat-Lagerstätten). Such extraordinary "windows" may markedly broaden our knowledge of biodiversity of the past. Here, we show a review of the invertebrate fossils from recently discovered locality in the Lower Ordovician Fenxiang Formation of Hubei Province in southern China revealing exceptional preservation of soft tissues. The fauna, generally of shallow-water aspect, contains linguloid brachiopods with a remarkably preserved pedicle, the oldest traces of nematode life activities, the oldest reliable record of hydroids, the first fossil antipatharian corals, a pyritized colonial organism of unknown affinity, supposed arthropod appendages, probable phosphatized scalidophoran worm embryo and other fossils. Our discovery supports the opinion that the famous soft-bodied preservation of Burgess Shale- or Chengjiang-type did not vanish from the fossil record in post-Cambrian times. The new finding represents a prelude to the Great Ordovician Biodiversification Event and provides evidence for calibration of molecular clock of several invertebrate lineages.

  2. Chemotactic behavior of the sperm of chitons (Mollusca: Polyplacophora).

    PubMed

    Miller, R L

    1977-11-01

    Observations of sperm behavior in the vicinity of gradients of egg-water or alcohol extracts of whole freshly-spawned eggs of several chitons reveal what appear to be directed movements of sperm up the gradient, resulting in the aggregation of motile sperm at the gradient source. Plots of the tracks of the sperm approaching the gradient source show that the cells increase the time during which they move toward the source and decrease the time spent moving away. Although this resembles the kinesis behavior shown by bacteria in a gradient, the path directions are markedly non-random. The reorientation behavior of thigmotactic sperm involves enlargement of the normal circular path diameter in the direction of the source and an alternation of tight loops and wide circular arcs, with the latter made in the direction of the source. The form of the path of attracted chiton sperm is like that observed during chemotaxis of the sperm of the hydroid Tubularia and the tunicate Ciona and resembles the behavior of Ciona sperm in that there is no increase in velocity as the cells move up the gradient. However, unlike the cnidarian and urochordate cases, the attracting substances extracted from chiton eggs do not act species-specifically.

  3. Polybrominated diphenyl ethers (PBDEs) alter larval settlement of marine intertidal organisms across three phyla via reducing bacterial abundance on the biofilms.

    PubMed

    Chiu, Jill M Y; Po, Beverly H K; Chan, Christine Y S; Lam, Michael H W; Qian, Pei-Yuan; Wu, Rudolf S S

    2012-07-17

    Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants over the last three decades, and are now ubiquitous in the marine environment. While the harmful effects of PBDEs on the abnormal development and reproductive impairment in mammals and fish are well documented, the effects on marine invertebrates remain virtually unknown. Using three model intertidal species accross three phyla, including the polychaete Hydroides elegans (Phylum Annelida), the gastropod Crepidula onyx (Phylum Mollusca), and the barnacle Balanus amphitrite (Phylum Arthopoda), this study demonstrated that (a) chronic exposure to BDE-47 (at spiking concentrations up to 1000 ng L(-1)) throughout the entire larval stage did not affect settlement, development or growth of all three species per se, despite bioaccumulation was clearly evident (measured body burden ranging from approximately 7000 to 13 000 ng BDE-47 g(-1) lipid), and (b) BDE-47, at measured concentrations of 15 and 113 ng g(-1) lipid, reduced the bacterial abundance in biofilms and resulted in a concomitant change in larval settlement pattern of all the model intertidal species across three phyla.

  4. Trans-generational responses to low pH depend on parental gender in a calcifying tubeworm.

    PubMed

    Lane, Ackley; Campanati, Camilla; Dupont, Sam; Thiyagarajan, Vengatesen

    2015-06-03

    The uptake of anthropogenic CO2 emissions by oceans has started decreasing pH and carbonate ion concentrations of seawater, a process called ocean acidification (OA). Occurring over centuries and many generations, evolutionary adaptation and epigenetic transfer will change species responses to OA over time. Trans-generational responses, via genetic selection or trans-generational phenotypic plasticity, differ depending on species and exposure time as well as differences between individuals such as gender. Males and females differ in reproductive investment and egg producing females may have less energy available for OA stress responses. By crossing eggs and sperm from the calcareous tubeworm Hydroides elegans (Haswell, 1883) raised in ambient (8.1) and low (7.8) pH environments, we observed that paternal and maternal low pH experience had opposite and additive effects on offspring. For example, when compared to offspring with both parents from ambient pH, growth rates of offspring of fathers or mothers raised in low pH were higher or lower respectively, but there was no difference when both parents were from low pH. Gender differences may result in different selection pressures for each gender. This may result in overestimates of species tolerance and missed opportunities of potentially insightful comparisons between individuals of the same species.

  5. Life in the colonies: learning the alien ways of colonial organisms.

    PubMed

    Winston, Judith E

    2010-12-01

    Who needs to go to outer space to study alien beings when the oceans of our own planet abound with bizarre and unknown creatures? Many of them belong to sessile clonal and colonial groups, including sponges, hydroids, corals, octocorals, ascidians, bryozoans, and some polychaetes. Their life histories, in many ways unlike our own, are a challenge for biologists. Studying their ecology, behavior, and taxonomy means trying to “think like a colony” to understand the factors important in their lives. Until the 1980s, most marine ecologists ignored these difficult modular organisms. Plant ecologists showed them ways to deal with the two levels of asexually produced modules and genetic individuals, leading to a surge in research on the ecology of clonal and colonial marine invertebrates. Bryozoans make excellent model colonial animals. Their life histories range from ephemeral to perennial. Aspects of their lives such as growth, reproduction, partial mortality due to predation or fouling, and the behavior of both autozooids and polymorphs can be studied at the level of the colony, as well as that of the individual module, in living colonies and over time.

  6. Autoaggressive, multi-headed and other mutant phenotypes in Hydractinia echinata (Cnidaria: Hydrozoa).

    PubMed

    Müller, Werner A

    2002-12-01

    In an inbreeding program conducted with the colonial hydroid Hydractinia echinata, each F1 mating produced up to 50% F2 offspring displaying an aberrant, clone-constant phenotype, hence referred to as mutant strain. In autoaggressive strains, in one or several areas of the colony autoreactive stolons direct their aggressive devices (stolon tips filled with cytotoxic stinging cells), normally used to kill allogeneic competitors for living space, towards neighboring stolons or polyps (hydranths) of their own colony. In these areas tumor-like masses of self-aggressive stolons were formed, in severe cases causing the death of the colony. Based on previous genetic studies, the interpretation proposed here attributes autoaggressive behavior to a mosaic-type alternative expression of arl (allorecognition) alleles in heterozygous individuals. Developmental mutant strains termed He-mh form supernumerary heads during regeneration and normal development as well. Common to all He-mh phenotypes isthe production of additional headsalong the bodycolumn of fully-grown polyps. The heads give rise to complete hydranths connected by a tube that derives from the gastric region of the original polyp and eventually transforms into a stolon. In bastol strains, polyps convert the basal region of their body column into a periderm-covered stolon from which the residual apical hydranth detaches. Colonies expressing both the He-mh and the bastol (bst) phenotype frequently lose detaching multi-headed hydranths and the colony disintegrates. The large number of mutant F2 offspring reveals high genetic variability in Hydractinia.

  7. Freeze avoidance: a dehydrating moss gathers no ice.

    PubMed

    Lenné, Thomas; Bryant, Gary; Hocart, Charles H; Huang, Cheng X; Ball, Marilyn C

    2010-10-01

    Using cryo-SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type; water-filled hydroid cells cavitated and were embolized at -4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ∼ 20% of their original volume at a nadir temperature of -20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from -20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ∼-12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to -20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing; remove that which freezes.

  8. Charles Wesley Hargitt (1852-1927): American educator and cnidarian biologist.

    PubMed

    Calder, Dale R

    2009-10-01

    Charles Wesley Hargitt was born near Lawrenceburg, Indiana, USA, and died at Syracuse, New York. After a brief career as a Methodist Episcopal Minister, he carried out graduate studies in biology at Illinois Wesleyan University and Ohio University. He served briefly on the faculty at Moores Hill College and later at Miami University of Ohio before receiving an appointment at Syracuse University. Hargitt spent 36 years at Syracuse, and for 21 years was a trustee of the Marine Biological Laboratory, Woods Hole, Massachusetts. His research encompassed animal behaviour, cell biology, development, ecology, natural history, and taxonomy, as well as education, eugenics, and theology, and he wrote or contributed to more than 100 publications in science. Approximately half of these were on Cnidaria, with 41 of them on Hydrozoa. His most important works in hydrozoan taxonomy were on species of the Woods Hole region, the Philippines, and south China. Hargitt was author of three genera and 48 species and subspecies ascribed to Hydrozoa, seven species of Anthozoa, and one species of Cubozoa. Four species of hydroids are named in his honour.

  9. Redescription of Licnophora chattoni Villeneuve-Brachon, 1939 (Ciliophora, Spirotrichea), associated with Zyzzyzus warreni Calder, 1988 (Cnidaria, Hydrozoa).

    PubMed

    da Silva-Neto, Inácio Domingos; da Silva Paiva, Thiago; Pedroso Dias, Roberto Júnio; Alexandre Campos, Carlos José; Migotto, Alvaro Esteves

    2012-01-01

    Licnophora chattoni, found in association with Zyzzyzus warreni, a tubulariid hydroid epizoic in sponges from São Sebastião (SP, Brazil), is redescribed and illustrated using light and electron microscopy. The ciliate has a flexible, transparent body formed by an oval anterior region linked to the posterior basal disc via a flexible neck region. Numerous cortical granules are observed scattered throughout the body and densely packed along the neck. The adoral zone is formed by about 81 external and 24 infundibular paramembranelles. The paroral membrane, formed by a row of long cilia arranged in monokinetids, extends through a groove in the body to the adhesive disc. Two dorsal kinetids are present along the right body margin and around the neck. The adhesive disc (18μm in diameter) lacks cilia in the area above the velum. The velum covers a row of dikinetids bearing long cilia and four dikineties, two or three of which are interrupted on the ventral surface. Nine to twelve macronuclear nodules connected by isthmuses are distributed in the cytoplasm, plus two nodules located in the adhesive disc and between those there is an ovate micronucleus. Copyright © 2011. Published by Elsevier GmbH.

  10. Larval behavioral, morphological changes, and nematocyte dynamics during settlement of actinulae of Tubularia mesembryanthemum, Allman 1871 (Hydrozoa: Tubulariidae).

    PubMed

    Yamashita, Keiji; Kawaii, Satoru; Nakai, Mitsuyo; Fusetani, Nobuhiro

    2003-06-01

    The marine colonial hydroid Tubularia mesembryanthemum produces a morphologically unique dispersive stage, the actinula larva. Detailed observations were made on the behaviors and nematocyte dynamics of actinula larvae during attachment and morphogenesis by employing microscopic and time lapse video techniques. These observations produced four primary results. (1) Actinula larvae demonstrated two forms of attachment: temporary attachment by atrichous isorhiza (AI)-nematocysts discharged from the aboral tentacle (AT) tips-and permanent settlement by cement secretion from the columnar gland cells of the basal protrusion. (2) During larval settlement, numerous AIs were discharged from the AT tips with sinuous movement and rubbing of the tentacles onto the substrata, leading to "nematocyte-printing" around the settlement site. (3) Simultaneous with the discharge of the AIs, migration of stenoteles, desmonemes, and microbasic mastigophores occurred, resulting in a dramatic change of nematocyte composition in the ATs after larval settlement. This was in parallel with changes in larval behavior and the tentacle function. (4) Nematocyte-printing behavior during settlement could be recognized as metamorphic behavior responsible for irreversible changes in AT function, from attachment to feeding and defense.

  11. The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide.

    PubMed

    Gravili, Cinzia; De Vito, Doris; Di Camillo, Cristina Gioia; Martell, Luis; Piraino, Stefano; Boero, Ferdinando

    2015-01-15

    The majority of Hydrozoa is represented by not readily noticeable, small species. In recent decades, however, taxonomic knowledge of the group has increased worldwide, with a significant number of investigations focused on the Mediterranean Sea. Over more than two decades, 115 species of hydrozoans were recorded from coastal waters along nearly 300 km of the Salento Peninsula (Apulia, Italy). For each species, records from different collections were merged into single sheets of a general database. For each species, the following information is reported: description, cnidome, biology, occurrence in Salento, worldwide distribution, and bibliography. Descriptions refer to the benthic hydroid stage and, when present, also to the planktonic medusa stage. The 115 species of Hydrozoa, recorded along the Salento coastline, represent 25% of the Mediterranean Hydrozoa fauna (totaling 461 species), and nearly 3% of 3,702 world's known species covered in a recent monograph. Four species are non-indigenous, three of them with invasive behavior (Clytia hummelincki, Clytia linearis, and Eudendrium carneum), and one species now very common (Eudendrium merulum) in Salento. The complete life cycle of Clytia paulensis (Vanhöffen, 1910) is described for the first time.

  12. The status of Plumularia lagenifera Allman, 1885 (Cnidaria, Hydrozoa) and related species.

    PubMed

    Schuchert, Peter

    2013-02-08

    The current status of Plumularia lagenifera Allman, 1885, a common thecate hydroid of the west coast of the USA and Canada, is problematic as it is difficult to distinguish from the near cosmopolitan and very variable Plumularia setacea. Type material of P. lagenifera and newly collected material of P. lagenifera and P. setacea from the region of the type locality of the former was used to compare it to P. setacea from the Atlantic. Measurements of a number of morphological traits were made and analysed using principal components analyses. Type material of the Californian Plumularia palmeri Nutting, 1900 was also included in the comparisons and confirmed the view of earlier workers that it is indistinguishable from P. setacea. Additionally, South African material referred to P. lagenifera by Millard (1975) was compared to the material from the NE Pacific. Plumularia lagenifera remains difficult to separate from P. setacea. The convex outer wall of the hydrotheca offers the only operational character to distinguish P. lagenifera from P. setacea, which always has straight or even concave hydrothecae. For morphological and biogeographic reasons, South African P. lagenifera sensu Millard (1975) should be referred to P. gaimardi (Lamouroux, 1924).

  13. Caprellids (Crustacea: Amphipoda) from India

    NASA Astrophysics Data System (ADS)

    Guerra-García, J. M.; Ganesh, T.; Jaikumar, M.; Raman, A. V.

    2010-12-01

    The caprellid fauna of India is investigated. A total of 538 samples (including algae, seagrasses, sponges, hydroids, ascidians, bryozoans, encrusted dead corals, coral rubble, fine and coarse sediments) were collected from 39 stations along the coast of India, covering a wide diversity of habitats from intertidal to 12 m water depth. A new species ( Jigurru longimanus n.sp.) is described, and figures of the 11 valid species reported so far from India are given together with a key for their identification. No caprellids were found in sediments from the northeast (16-20ºN) coast of India while they were abundant in the southeast and west coast. Decreases in salinity due to river discharges associated with lower values of oxygen, higher water temperatures and lower nutrient inputs along the east coast could explain these differences in caprellid composition between the two coastlines. Significantly, lower abundance of caprellids in India, as in other tropical ecosystems, is probably related to the lack of species belonging to the genus Caprella, which reach very high abundances in temperate waters.

  14. Bifurcation analysis of brown tide by reaction-diffusion equation using finite element method

    SciTech Connect

    Kawahara, Mutsuto; Ding, Yan

    1997-03-01

    In this paper, we analyze the bifurcation of a biodynamics system in a two-dimensional domain by virtue of reaction-diffusion equations. The discretization method in space is the finite element method. The computational algorithm for an eigenspectrum is described in detail. On the basis of an analysis of eigenspectra according to Helmholtz`s equation, the discrete spectra in regards to the physical variables are numerically obtained in two-dimensional space. In order to investigate this mathematical model in regards to its practical use, we analyzed the stability of two cases, i.e., hydranth regeneration in the marine hydroid Tubularia and a brown tide in a harbor in Japan. By evaluating the stability according to the linearized stability definition, the critical parameters for outbreaks of brown tide can be theoretically determined. In addition, results for the linear combination of eigenspectrum coincide with the distribution of the observed brown tide. Its periodic characteristic was also verified. 10 refs., 8 figs., 5 tabs.

  15. Trans-generational responses to low pH depend on parental gender in a calcifying tubeworm

    PubMed Central

    Lane, Ackley; Campanati, Camilla; Dupont, Sam; Thiyagarajan, Vengatesen

    2015-01-01

    The uptake of anthropogenic CO2 emissions by oceans has started decreasing pH and carbonate ion concentrations of seawater, a process called ocean acidification (OA). Occurring over centuries and many generations, evolutionary adaptation and epigenetic transfer will change species responses to OA over time. Trans-generational responses, via genetic selection or trans-generational phenotypic plasticity, differ depending on species and exposure time as well as differences between individuals such as gender. Males and females differ in reproductive investment and egg producing females may have less energy available for OA stress responses. By crossing eggs and sperm from the calcareous tubeworm Hydroides elegans (Haswell, 1883) raised in ambient (8.1) and low (7.8) pH environments, we observed that paternal and maternal low pH experience had opposite and additive effects on offspring. For example, when compared to offspring with both parents from ambient pH, growth rates of offspring of fathers or mothers raised in low pH were higher or lower respectively, but there was no difference when both parents were from low pH. Gender differences may result in different selection pressures for each gender. This may result in overestimates of species tolerance and missed opportunities of potentially insightful comparisons between individuals of the same species. PMID:26039184

  16. Decoupling the response of an estuarine shrimp to architectural components of habitat structure

    PubMed Central

    Chang, Andrew L.; Ruiz, Gregory M.

    2016-01-01

    In order to explore biotic attraction to structure, we examined how the amount and arrangement of artificial biotic stalks affected responses of a shrimp, Palaemon macrodactylus, absent other proximate factors such as predation or interspecific competition. In aquaria, we tested the effect of differing densities of both un-branched and branched stalks, where the amount of material in the branched stalk equaled four-times that of the un-branched. The results clearly showed that it was the amount of material, not how it was arranged, that elicited responses from shrimp. Also, although stalks were not purposefully designed to mimic structural elements found in nature, they did resemble biogenic structure such as hydroids, algae, or plants. In order to test shrimp attraction to a different, perhaps more unfamiliar habitat type, we examined responses to plastic “army men.” These structural elements elicited similar attraction of shrimp, and, in general, shrimp response correlated well with the fractal dimension of both stalks and army men. Overall, these results indicate that attraction to physical structure, regardless of its nature, may be an important driver of high abundances often associated with complex habitats. PMID:27547551

  17. Integration of Morphological Data into Molecular Phylogenetic Analysis: Toward the Identikit of the Stylasterid Ancestor

    PubMed Central

    Puce, Stefania; Pica, Daniela; Schiaparelli, Stefano; Negrisolo, Enrico

    2016-01-01

    Stylasteridae is a hydroid family including 29 worldwide-distributed genera, all provided with a calcareous skeleton. They are abundant in shallow and deep waters and represent an important component of marine communities. In the present paper, we studied the evolution of ten morphological characters, currently used in stylasterid taxonomy, using a phylogenetic approach. Our results indicate that stylasterid morphology is highly plastic and that many events of independent evolution and reversion have occurred. Our analysis also allows sketching a possible identikit of the stylasterid ancestor. It had calcareous skeleton, reticulate-granular coenosteal texture, polyps randomly arranged, gastrostyle, and dactylopore spines, while lacking a gastropore lip and dactylostyles. If the ancestor had single or double/multiple chambered gastropore tube is uncertain. These data suggest that the ancestor was similar to the extant genera Cyclohelia and Stellapora. Our investigation is the first attempt to integrate molecular and morphological information to clarify the stylasterid evolutionary scenario and represents the first step to infer the stylasterid ancestor morphology. PMID:27537333

  18. Importance of seep primary production to Lophelia pertusa and associated fauna in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Becker, Erin L.; Cordes, Erik E.; Macko, Stephen A.; Fisher, Charles R.

    2009-05-01

    To investigate the importance of seep primary production to the nutrition of Lophelia pertusa and associated communities and examine local trophic interactions, we analyzed stable carbon, nitrogen, and sulfur compositions in seven quantitative L. pertusa community collections. A significant seep signature was only detected in one of the 35 species tested ( Provanna sculpta, a common seep gastropod) despite the presence of seep fauna at the three sample sites. A potential predator of L. pertusa was identified ( Coralliophila sp.), and a variety of other trophic interactions among the fauna occupying the coral framework were suggested by the data, including the galatheid crab Munidopsis sp. 2 feeding upon hydroids and the polychaete Eunice sp. feeding upon the sabellid polychaete Euratella sp. Stable carbon abundances were also determined for different sections of L. pertusa skeleton representing different stages in the growth and life of the aggregation. There was no temporal trend detected in the skeleton isotope values, suggesting that L. pertusa settles in these areas only after seepage has largely subsided. Isotope values of individual taxa that were collected from both L. pertusa and vestimentiferan habitats showed decreasing reliance upon seep primary production with average age of the vestimentiferan aggregation, and finally, no seep signature was detected in the coral collections. Together our data suggest that it is the presence of authigenic carbonate substrata, a product of past seep microbial activity, as well as hydrodynamic processes that drive L. pertusa occurrence at seep sites in the Gulf of Mexico, not nutritional dependence upon primary production by seep microbes.

  19. Succession of the ecosystems of the Aral Sea during its transition from oligohaline to polyhaline water body

    NASA Astrophysics Data System (ADS)

    Mirabdullayev, Iskandar M.; Joldasova, Iliya M.; Mustafaeva, Zuri A.; Kazakhbaev, Saparbay; Lyubimova, Svetlana A.; Tashmukhamedov, Bekdjan A.

    2004-06-01

    During 22 field trips from 1990 to 2002 (mainly the western basin of the Large Aral) data on salinity, phytoplankton, zooplankton, zoobenthos and fish fauna have been collected. In 2002, the salinity of the western basin reached 75 ppt, while that in the eastern basin, 150 ppt. In 1999-2002, 159 species of planktonic algae have been recorded. This is approximately twice as low as recorded before. The diversity of Cyanophyta, Pyrrhophyta and Chlorophyta in particular has dropped in the past few years. As before, currently Bacillariophyta is the most diverse plankton. However, the composition of dominants has changed. Once previously dominant species, Actinocyclus ehrenbergii, vanished from the plankton of the Aral Sea and was replaced by such diatoms as Amphora coffeaformis, A. coffeaformis var. acutiuscula and Synedra tabulata var. parva. Since 1970s, a gradual decrease in the diversity of zooplankton has been taking place. Since 1997, the formerly dominant Calanipeda aquaedulcis vanished, which apparently was the reason for the emergence of Moina salina and Artemia parthenogenetica. Since 2000, artemia has been dominant in the plankton of the Aral Sea, constituting 99% of the zooplankton biomass. In the 1970-1980s, a rapid decrease in the biodiversity of the zoobenthos was observed. In the 1990s, most aboriginal and introduced species became extinct. Currently, the bivalve mollusk Syndosmya segmentum, the ostracod Cyprideis torosa and larvae of the dipteran Chironomus salinarius can still be recorded in the western basin. In the eastern basin no benthos is observed. By 1998, in the Large Aral, only five fish species survived: baltic herring Clupea harengus membras, flounder Platichthys flesus luscus, atherine Atherina boyeri caspia and bullheads Neogobius fluviatilis and Potamoschistus caucasicus. Since 2002, only flounder and atherina have been recorded in the western basin of the Large Aral. No fish have been recorded in the eastern part of the Aral Sea in 2002

  20. Collision and displacement vulnerability among marine birds of the California Current System associated with offshore wind energy infrastructure

    USGS Publications Warehouse

    Adams, Josh; Kelsey, Emily C.; Felis, Jonathan J.; Pereksta, David M.

    2016-10-27

    With growing climate change concerns and energy constraints, there is an increasing need for renewable energy sources within the United States and globally. Looking forward, offshore wind-energy infrastructure (OWEI) has the potential to produce a significant proportion of the power needed to reach our Nation’s renewable energy goal. Offshore wind-energy sites can capitalize open areas within Federal waters that have persistent, high winds with large energy production potential. Although there are few locations in the California Current System (CCS) where it would be acceptable to build pile-mounted wind turbines in waters less than 50 m deep, the development of technology able to support deep-water OWEI (>200 m depth) could enable wind-energy production in the CCS. As with all human-use of the marine environment, understanding the potential impacts of wind-energy infrastructure on the marine ecosystem is an integral part of offshore wind-energy research and planning. Herein, we present a comprehensive database to quantify marine bird vulnerability to potential OWEI in the CCS (see https://doi.org/10.5066/F79C6VJ0). These data were used to quantify marine bird vulnerabilities at the population level. For 81 marine bird species present in the CCS, we created three vulnerability indices: Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability. Population Vulnerability was used as a scaling factor to generate two comprehensive indicies: Population Collision Vulnerability (PCV) and Population Displacement Vulnerability (PDV). Within the CCS, pelicans, terns (Forster’s [Sterna forsteri], Caspian [Hydroprogne caspia], Elegant [Thalasseus elegans], and Least Tern [Sternula antillarum]), gulls (Western [Larus occidentalis] and Bonaparte’s Gull [Chroicocephalus philadelphia]), South Polar Skua (Stercorarius maccormicki), and Brandt’s Cormorant (Phalacrocorax penicillatus) had the greatest PCV scores. Brown Pelican (Pelicanus occidentalis

  1. Pacific Coast Caspian Terns: Dynamics of an expanding population

    USGS Publications Warehouse

    Gill, Robert E.; Mewaldt, L. Richard

    1983-01-01

    Nesting distribution, age-related seasonal movements, survivorship, and mechanisms of population expansion in Pacific Coast Caspian Terns (Sterna caspia) were examined primarily through analysis of 412 recoveries of birds banded as juveniles between 1935 and 1980. Since the beginning of this century, the population has shifted from nesting in numerous small colonies associated with freshwater marshes in interior California and southern Oregon to nesting primarily in large colonies on human-created habitats along the coast. Colonies at Grays Harbor, Washington and San Francisco and San Diego bays, California account for 77% of the current Pacific Coast population (6,000 pairs), which has breeding and wintering areas separate from those of populations east of the continental divide. There also appears to be some segregation on the wintering grounds by birds from the three major colonies within the Pacific population. Age-related seasonal movements in the Pacific population are characterized by (1) a brief period of northward dispersal by newly fledged birds before migrating to the wintering grounds, (2) a residency on the wintering grounds through their second winter, (3) a return to the breeding grounds the third summer, when most birds are thought to prospect breeding sites and some may breed, and (4) attainment of adulthood the fourth summer, with subsequent annual movements between wintering and breeding grounds.The Pacific population has increased 70% since 1960, apparently all by intrinsic growth. Over half (57%) of the fledglings reach their fourth year, and they have a subsequent annual survival rate of 89% and a mean breeding life expectancy of 8.6 yr. An average annual fledging rate of 0.64 young per pair was calculated as necessary to have provided the observed growth of the population during its recent expansion. Growth of some of the individual colonies, however, particularly those in Washington, could only have resulted from extensive recruitment of

  2. Quantifying avian predation on fish populations: integrating predator-specific deposition probabilities in tag-recovery studies

    USGS Publications Warehouse

    Hostetter, Nathan J.; Evans, Allen F.; Cramer, Bradley M.; Collis, Ken; Lyons, Donald E.; Roby, Daniel D.

    2015-01-01

    Accurate assessment of specific mortality factors is vital to prioritize recovery actions for threatened and endangered species. For decades, tag recovery methods have been used to estimate fish mortality due to avian predation. Predation probabilities derived from fish tag recoveries on piscivorous waterbird colonies typically reflect minimum estimates of predation due to an unknown and unaccounted-for fraction of tags that are consumed but not deposited on-colony (i.e., deposition probability). We applied an integrated tag recovery modeling approach in a Bayesian context to estimate predation probabilities that accounted for predator-specific tag detection and deposition probabilities in a multiple-predator system. Studies of PIT tag deposition were conducted across three bird species nesting at seven different colonies in the Columbia River basin, USA. Tag deposition probabilities differed significantly among predator species (Caspian ternsHydroprogne caspia: deposition probability = 0.71, 95% credible interval [CRI] = 0.51–0.89; double-crested cormorants Phalacrocorax auritus: 0.51, 95% CRI = 0.34–0.70; California gulls Larus californicus: 0.15, 95% CRI = 0.11–0.21) but showed little variation across trials within a species or across years. Data from a 6-year study (2008–2013) of PIT-tagged juvenile Snake River steelhead Oncorhynchus mykiss (listed as threatened under the Endangered Species Act) indicated that colony-specific predation probabilities ranged from less than 0.01 to 0.17 and varied by predator species, colony location, and year. Integrating the predator-specific deposition probabilities increased the predation probabilities by a factor of approximately 1.4 for Caspian terns, 2.0 for double-crested cormorants, and 6.7 for California gulls compared with traditional minimum predation rate methods, which do not account for deposition probabilities. Results supported previous findings on the high predation impacts from strictly piscivorous

  3. Collision and displacement vulnerability among marine birds of the California Current System associated with offshore wind energy infrastructure

    USGS Publications Warehouse

    Adams, Josh; Kelsey, Emily C.; Felis, Jonathan J.; Pereksta, David M.

    2016-10-27

    With growing climate change concerns and energy constraints, there is an increasing need for renewable energy sources within the United States and globally. Looking forward, offshore wind-energy infrastructure (OWEI) has the potential to produce a significant proportion of the power needed to reach our Nation’s renewable energy goal. Offshore wind-energy sites can capitalize open areas within Federal waters that have persistent, high winds with large energy production potential. Although there are few locations in the California Current System (CCS) where it would be acceptable to build pilemounted wind turbines in waters less than 50 m deep, the development of technology able to support deep-water OWEI (>200 m depth) could enable wind-energy production in the CCS. As with all humanuse of the marine environment, understanding the potential impacts of wind-energy infrastructure on the marine ecosystem is an integral part of offshore wind-energy research and planning. Herein, we present a comprehensive database to quantify marine bird vulnerability to potential OWEI in the CCS (see http://dx.doi.org/10.5066/F79C6VJ0). These data were used to quantify marine bird vulnerabilities at the population level. For 81 marine bird species present in the CCS, we created three vulnerability indices: Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability. Population Vulnerability was used as a scaling factor to generate two comprehensive indicies: Population Collision Vulnerability (PCV) and Population Displacement Vulnerability (PDV). Within the CCS, pelicans, terns (Forster’s [Sterna forsteri], Caspian [Hydroprogne caspia], Elegant [Thalasseus elegans], and Least Tern [Sternula antillarum]), gulls (Western [Larus occidentalis] and Bonaparte’s Gull [Chroicocephalus philadelphia]), South Polar Skua (Stercorarius maccormicki), and Brandt’s Cormorant (Phalacrocorax penicillatus) had the greatest PCV scores. Brown Pelican (Pelicanus occidentalis

  4. Mid-late Holocene climate and ecology reconstruction around the Lagoon Mae-ho, East Korea based on diatom assemblage

    NASA Astrophysics Data System (ADS)

    Katsuki, K.; Lim, J.; Nahm, W.; Nakanishi, T.

    2012-12-01

    Diatom assemblage analysis in core sediment samples, PMR-2, from around Lagoon Mae-ho was examined for the purpose of evaluating the climate and local ecosystem change during the mid-late Holocene. Core PMR-2 is approximately 11 m length core, which was obtained from a front of reclaimed land around Lagoon Mae-ho in northeastern coast of Korea. Except for the top 2.5 m, preserved condition of diatom remain was well throughout the core. Radiocarbon ages were measured by a 1MV AMS facility at KIGAM. In particularly, high diatom remains were contained in obvious lamina layer between 7.0-9.5 m depth. Based on the diatom assemblage analysis, core PMR-2 was probably located under the small channel before 5,800 cal yr BP, which was under the lamina layer. Diatom assemblage was composed by the fresh and brackish taxa at that layer. Eutrophic lagoon was formed along the sea level increasing about 5,800 cal yr BP. Since 5,800 cal yr BP, location of core PMR-2 was covered by lagoon condition. Dominant taxa were eutrophic brackish diatom such as Cyclotella caspia and Cyclotella striata. Obvious lamina layer was composed under this condition. Since 4,000 cal yr BP, water exchange rate between the sea and paleo-lagoon Mae-ho was increased. This was indicated by the increasing marine-brackish diatom taxa. Anoxic bottom condition of the paleo-lagoon Mae-ho was resolved due to the increasing sea water inflow, and lamina layer was disappeared. After then, water depth of lagoon Mae-ho had become shallow gradually. Coring site was located around coastal marsh, and finally the site was reclaimed by human activity in recent. As mention above, obvious lamina was composed under the eutropic lagoon condition between 4,000 and 5,800 cal yr BP (7.0-9.5 m depth). These lamina were annual layers, was set of spring diatom bloom layer and other season's layer. In this presentation, we will discuss not only late to mid Holocene environmental change, but also discuss the short term climate

  5. Recovery of coded wire tags at a caspian tern colony in san francisco bay: A technique to evaluate impacts of avian predation on juvenile salmonids

    USGS Publications Warehouse

    Evans, A.F.; Roby, D.D.; Collis, K.; Cramer, B.M.; Sheggeby, J.A.; Adrean, L.J.; Battaglia, D.S.; Lyons, Donald E.

    2011-01-01

    We recovered coded wire tags (CWTs) from a colony of Caspian terns Hydroprogne caspia on Brooks Island in San Francisco Bay, California, to evaluate predation on juvenile salmonids originating from the Sacramento and San Joaquin rivers. Subsamples of colony substrate representing 11.7% of the nesting habitat used by the terns yielded 2,079 salmonid CWTs from fish released and subsequently consumed by terns in 2008. The estimated number of CWTs deposited on the entire tern colony was 40,143 (ranging from 26,763 to 80,288), once adjustments were made to account for tag loss and the total amount of nesting habitat used by terns. Tags ingested by terns and then egested on the colony were undamaged, and the tags' complete numeric codes were still identifiable. The CWTs found on the tern colony indicated that hatchery Chinook salmon Oncorhynchus tshawytscha trucked to and released in San Pablo Bay were significantly more likely to be consumed by Caspian terns than Chinook salmon that migrated in-river to the bay; 99.7% of all tags recovered were from bay-released Chinook salmon. Of the CWTs recovered on the tern colony, 98.0% were from fall-run Chinook salmon, indicating a higher susceptibility to tern predation than for the spring run type. None of the approximately 518,000 wild Chinook salmon that were coded-wire-tagged and released in the basin were recovered on the tern colony, suggesting that the impacts on wild, U.S. Endangered Species Act-listed Chinook salmon populations were minimal in 2008. Overall, we estimate that 0.3% of the approximately 12.3 million coded-wire-tagged Chinook salmon released in the basin in 2008 were subsequently consumed by Caspian terns from the Brooks Island colony. These results indicate that CWTs implanted in juvenile salmon can be recovered from a piscivorous waterbird colony and used to evaluate smolt losses for runs that are tagged. Abstract We recovered coded wire tags (CWTs) from a colony of Caspian terns Hydroprogne caspia on

  6. The potential for translocation of marine species via small-scale disruptions to antifouling surfaces.

    PubMed

    Piola, Richard F; Johnston, Emma L

    2008-01-01

    Vessel hull fouling is a major vector for the translocation of nonindigenous species (NIS). Antifouling (AF) paints are the primary method for preventing the establishment and translocation of fouling species. However, factors such as paint age, condition and method of application can all reduce the effectiveness of these coatings. Areas of hull that escape AF treatment (through limited application or damage) constitute key areas that may be expected to receive high levels of fouling. The investigation focused on whether small-scale (mm(2) to cm(2)) areas of unprotected surface or experimental 'scrapes' provided sufficient area for the formation of fouling assemblages within otherwise undamaged AF surfaces. Recruitment of fouling taxa such as algae, spirorbids and hydroids was recorded on scrapes as narrow as 0.5 cm wide. The abundance and species richness of fouling assemblages developing on scrapes > or =1 cm often equalled or surpassed levels observed in reference assemblages totally unprotected by AF coatings. Experiments were conducted at three sites within the highly protected and isolated marine park surrounding Lady Elliott Island at the southernmost tip of the Great Barrier Reef, Australia. Several NIS were recorded on scrapes of AF coated surfaces at this location, with 1-cm scrapes showing the greatest species richness and abundance of NIS relative to all other treatments (including controls) at two of the three sites investigated. Slight disruptions to newly antifouled surfaces may be all that is necessary for the establishment of fouling organisms and the translocation of a wide range of invasive taxa to otherwise highly protected marine areas.

  7. Amphimixis and the individual in evolving populations: does Weismann's Doctrine apply to all, most or a few organisms?

    NASA Astrophysics Data System (ADS)

    Niklas, Karl J.; Kutschera, Ulrich

    2014-05-01

    The German biologist August Weismann (1834-1914) proposed that amphimixis (sexual reproduction) creates variability for natural selection to act upon, and hence he became one of the founders of the Neo-Darwinian theory of biological evolution. He is perhaps best known for what is called "Weismann's Doctrine" or "Weismann's Barrier" (i.e. the irreversible separation of somatic and germ cell functionalities early during ontogeny in multicellular organisms). This concept provided an unassailable argument against "soft inheritance" sensu Lamarck and informed subsequent theorists that the only "individual" in the context of evolution is the mature, reproductive organism. Herein, we review representative model organisms whose embryology conforms to Weismann's Doctrine (e.g. flies and mammals) and those that do not (e.g. freshwater hydroids and plants) based on this survey and the Five Kingdoms of Life scheme; we point out that most species (notably bacteria, fungi, protists and plants) are "non-Weismannian" in ways that make a canonical definition of the "individual" problematic if not impossible. We also review critical life history functional traits that allow us to create a matrix of all theoretically conceivable life cycles (for eukaryotic algae, embryophytes, fungi and animals), which permits us to establish where this scheme Weismann's Doctrine holds true and where it does not. In addition, we argue that bacteria, the dominant organisms of the biosphere, exist in super-cellular biofilms but rarely as single (planktonic) microbes. Our analysis attempts to show that competition among genomic variants in cell lineages played a critical part in the evolution of multicellularity and life cycle diversity. This feature was largely ignored during the formulation of the synthetic theory of biological evolution and its subsequent elaborations.

  8. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria.

    PubMed

    Dahlgren, Thomas G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Ikebe, Chiho; Watling, Les; Smith, Craig R; Glover, Adrian G

    2016-01-01

    We present data from a DNA taxonomy register of the abyssal Cnidaria collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area 'UK-1' in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. This is the second paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Data were collected from the UK-1 exploration area following the methods described in Glover et al. (2015b). Morphological and genetic data are presented for 10 species and 18 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 2 primnoid octocorals, 2 isidid octocorals, 1 anemone, 4 hydroids (including 2 pelagic siphonophores accidentally caught) and a scyphozoan jellyfish (in the benthic stage of the life cycle). Two taxa matched previously published genetic sequences (pelagic siphonophores), two taxa matched published morphological descriptions (abyssal primnoids described from the same locality in 2015) and the remaining 6 taxa are potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. We have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. For some of the specimens we also provide image data collected at the seabed by ROV, wich may facilitate more accurate taxon designation in coming ROV or AUV surveys.

  9. Pelagic Sargassum community change over a 40-year period: temporal and spatial variability.

    PubMed

    Huffard, C L; von Thun, S; Sherman, A D; Sealey, K; Smith, K L

    2014-01-01

    Pelagic forms of the brown algae (Phaeophyceae) Sargassum spp. and their conspicuous rafts are defining characteristics of the Sargasso Sea in the western North Atlantic. Given rising temperatures and acidity in the surface ocean, we hypothesized that macrofauna associated with Sargassum in the Sargasso Sea have changed with respect to species composition, diversity, evenness, and sessile epibiota coverage since studies were conducted 40 years ago. Sargassum communities were sampled along a transect through the Sargasso Sea in 2011 and 2012 and compared to samples collected in the Sargasso Sea, Gulf Stream, and south of the subtropical convergence zone from 1966 to 1975. Mobile macrofauna communities exhibited changes in community structure and declines in diversity and evenness within a 6-month time period (August 2011-February 2012). Equivalent declines in diversity and evenness were recorded in the same region (Sargasso Sea, 25°-29°N) in 1972-1973. Recent community structures were unlike any documented historically, whether compared to sites of the same latitude range within the Sargasso Sea, or the broader historical dataset of sites ranging across the Sargasso Sea, Gulf Stream, and south of the subtropical convergence zone. Recent samples also recorded low coverage by sessile epibionts, both calcifying forms and hydroids. The diversity and species composition of macrofauna communities associated with Sargassum might be inherently unstable. While several biological and oceanographic factors might have contributed to these observations, including a decline in pH, increase in summer temperatures, and changes in the abundance and distribution of Sargassum seaweed in the area, it is not currently possible to attribute direct causal links.

  10. Pattern of cell proliferation in embryogenesis and planula development ofHydractinia echinata predicts the postmetamorphic body pattern.

    PubMed

    Kroiher, Michael; Plickert, Günter; Müller, Werner A

    1990-11-01

    During embryogenesis and planula development of the colonial hydroidHydractinia echinata cell proliferation decreases in a distinct spatio-temporal pattern. Arrest in S-phase activity appears first in cells localized at the posterior and then subsequently at the anterior pole of the elongating embryo. These areas do not resume S-phase activity, even during the metamorphosis of the planula larva into the primary polyp. Tissue containing the quiescent cells gives rise to the terminal structures of the polyp. The posterior area of the larva becomes the hypostome and tentacles, while the anterior part of the larva develops into the basal plate and stolon tips. In mature planulae only a very few cells continue to proliferate. These cells are found in the middle part of the larva. Labelling experiments indicate that the prospective material of the postmetamorphic tentacles and stolon tips originates from cells which have exited from the cell cycle in embryogenesis or early in planula development. Precursor cells of the nematocytes which appear in the tentacles of the polyp following metamorphosis appear to have ceased cycling before the 38th hour of embryonic development. The vast majority of the cells that constitute the stolon tips of the primary polyp leave the cell cycle not later than 58 h after the beginning of development. We also report the identification of a cell type which differentiates in the polyp without passing through a post-metamorphic S-phase. The cell type appears to be neural in origin, based upon the identification of a neuropeptide of the FMRFamide type.

  11. Cnidarian phylogenetic relationships as revealed by mitogenomics

    PubMed Central

    2013-01-01

    Background Cnidaria (corals, sea anemones, hydroids, jellyfish) is a phylum of relatively simple aquatic animals characterized by the presence of the cnidocyst: a cell containing a giant capsular organelle with an eversible tubule (cnida). Species within Cnidaria have life cycles that involve one or both of the two distinct body forms, a typically benthic polyp, which may or may not be colonial, and a typically pelagic mostly solitary medusa. The currently accepted taxonomic scheme subdivides Cnidaria into two main assemblages: Anthozoa (Hexacorallia + Octocorallia) – cnidarians with a reproductive polyp and the absence of a medusa stage – and Medusozoa (Cubozoa, Hydrozoa, Scyphozoa, Staurozoa) – cnidarians that usually possess a reproductive medusa stage. Hypothesized relationships among these taxa greatly impact interpretations of cnidarian character evolution. Results We expanded the sampling of cnidarian mitochondrial genomes, particularly from Medusozoa, to reevaluate phylogenetic relationships within Cnidaria. Our phylogenetic analyses based on a mitochogenomic dataset support many prior hypotheses, including monophyly of Hexacorallia, Octocorallia, Medusozoa, Cubozoa, Staurozoa, Hydrozoa, Carybdeida, Chirodropida, and Hydroidolina, but reject the monophyly of Anthozoa, indicating that the Octocorallia + Medusozoa relationship is not the result of sampling bias, as proposed earlier. Further, our analyses contradict Scyphozoa [Discomedusae + Coronatae], Acraspeda [Cubozoa + Scyphozoa], as well as the hypothesis that Staurozoa is the sister group to all the other medusozoans. Conclusions Cnidarian mitochondrial genomic data contain phylogenetic signal informative for understanding the evolutionary history of this phylum. Mitogenome-based phylogenies, which reject the monophyly of Anthozoa, provide further evidence for the polyp-first hypothesis. By rejecting the traditional Acraspeda and Scyphozoa hypotheses, these analyses suggest that

  12. Somatostatin signaling system as an ancestral mechanism: Myoregulatory activity of an Allatostatin-C peptide in Hydra.

    PubMed

    Alzugaray, María Eugenia; Hernández-Martínez, Salvador; Ronderos, Jorge Rafael

    2016-08-01

    The coordination of physiological processes requires precise communication between cells. Cellular interactions allow cells to be functionally related, facilitating the maintaining of homeostasis. Neuropeptides functioning as intercellular signals are widely distributed in Metazoa. It is assumed that neuropeptides were the first intercellular transmitters, appearing early during the evolution. In Cnidarians, neuropeptides are mainly involved in neurotransmission, acting directly or indirectly on epithelial muscle cells, and thereby controlling coordinated movements. Allatostatins are a group of chemically unrelated neuropeptides that were originally characterized based on their ability to inhibit juvenil hormone synthesis in insects. Allatostatin-C has pleiotropic functions, acting as myoregulator in several insects. In these studies, we analyzed the myoregulatory effect of Aedes aegypti Allatostatin-C in Hydra sp., a member of the phylum Cnidaria. Allatostatin-C peptide conjugated with Qdots revealed specifically distributed cell populations that respond to the peptide in different regions of hydroids. In vivo physiological assays using Allatostatin-C showed that the peptide induced changes in shape and length in tentacles, peduncle and gastrovascular cavity. The observed changes were dose and time dependent suggesting the physiological nature of the response. Furthermore, at highest doses, Allatostatin-C induced peristaltic movements of the gastrovascular cavity resembling those that occur during feeding. In silico search of putative Allatostatin-C receptors in Cnidaria showed that genomes predict the existence of proteins of the somatostatin/Allatostatin-C receptors family. Altogether, these results suggest that Allatostatin-C has myoregulatory activity in Hydra sp, playing a role in the control of coordinated movements during feeding, indicating that Allatostatin-C/Somatostatin based signaling might be an ancestral mechanism.

  13. Speciation of triphenyltin compounds using Moessbauer spectroscopy. Final report

    SciTech Connect

    Eng, G.

    1993-11-01

    Organotin compounds have been used widely as the active agent in antifouling marine paints. Organotin compounds, i.e., tributyltin compounds (TBTs) and triphenyltin compounds (TPTs) have been found to be effective in preventing the unwanted attachment and development of aquatic organisms such as barnacles, sea grass and hydroids on ships, hulls and underwater surfaces. However, these organotin compounds have been found to be toxic to non-targeted marine species as well. While speciation of tributyltins in environmental water systems has received much attention in the literature, little information concerning the speciation of triphenyltins is found. Therefore, it would be important to study the fate of TPTs in the aquatic environment, particularly in sediments, both oxic and anoxic, in order to obtain speciation data. Since marine estuaries consist of areas with varying salinity and pH, it is important to investigate the speciation of these compounds under varying salinity conditions. In addition, evaluation of the speciation of these compounds as a function of pH would give an insight into how these compounds might interact with sediments in waters where industrial chemical run-offs can affect the pH of the estuarine environment. Finally, since organotins are present in both salt and fresh water environments, the speciation of the organotins in seawater and distilled water should also be studied. Moessbauer spectroscopy would provide a preferred method to study the speciation of triphenyltins as they leach from marine paints into the aquatic environment. Compounds used in this study are those triphenyltin compounds that are commonly incorporated into marine paints such as triphenyltin fluoride (TPTF), triphenyltin acetate (TPTOAc), triphenyltin chloride (TPTCl) and triphenyltin hydroxide (TPTOH).

  14. Exploring trophic strategies of exotic caprellids (Crustacea: Amphipoda): Comparison between habitat types and native vs introduced distribution ranges

    NASA Astrophysics Data System (ADS)

    Ros, Macarena; Tierno de Figueroa, José Manuel; Guerra-García, José Manuel; Navarro-Barranco, Carlos; Lacerda, Mariana Baptista; Vázquez-Luis, Maite; Masunari, Setuko

    2014-02-01

    The trophic ecology of non-native species is a key aspect to understand their invasion success and the community effects. Despite the important role of caprellid amphipods as trophic intermediates between primary producers and higher levels of marine food webs, there is very little information on their feeding habits. This is the first comprehensive study on the trophic strategies of two co-occurring introduced caprellids in the Spanish coasts: Caprella scaura and Paracaprella pusilla. The diet of 446 specimens of C. scaura and 230 of P. pusilla was analyzed to investigate whether there were differences in the feeding habits in relation to habitat characteristics (natural vs artificial hard substrata), type of host substrata (bryozoans and hydroids) and native vs introduced distribution ranges (Brazil vs Spain). Results revealed differences in diet preferences of the two species that have important implications for their trophic behaviour and showed a limited food overlap, which may favour their coexistence in introduced areas. In general terms, P. pusilla is a predator species, showing preference by crustacean prey in all of its life stages, while C. scaura feeds mainly on detritus. Although no sex-related diet shifts were observed in either of the species, evidence of ontogenetic variation in diet of C. scaura was found, with juveniles feeding on more amount of prey than adults. No diet differences were found between native and introduced populations within the same habitat type. However, P. pusilla exhibited a shift in its diet when different habitats were compared in the same distribution area, and C. scaura showed a flexible feeding behaviour between different host substrata in the same habitat type. This study shows that habitat characteristics at different scales can have greater influence on the feeding ecology of exotic species than different distribution ranges, and support the hypothesis that a switch between feeding strategies depending on habitat

  15. Toxicity of chromated copper arsenate (CCA)-treated wood to non-target marine fouling communities in Langstone Harbour, Portsmouth, UK.

    PubMed

    Brown, C J; Eaton, R A

    2001-04-01

    The effect of the anti-marine-borer timber preservative chromated copper arsenate (CCA) (a pressure impregnated solution of copper, chromium and arsenic compounds) on non-target marine fouling animals was investigated during a subtidal exposure trial. Panels of Scots pine treated to target retentions of 12, 24 and 48 kg CCA per m-3 of wood, plus untreated controls were submerged at a coastal site on the south coast of the UK for 6, 12 and 18 months. After each exposure period the fouling communities that formed on the surface of panels were assessed both qualitatively and quantitatively. Community structure was similar on panels treated to the three CCA loadings, but was significantly different from community structure on untreated panels. The total number of species (species richness) was similar on all panels, although the number of individual organisms attached to the surface of panels was significantly higher on CCA-treated panels than on untreated panels. k-dominance curves revealed that the difference in numbers of individuals between CCA-treated and untreated panels was caused by higher numbers of the dominant species (Elminius modestus, Hydroides ezoensis, and Electra pilosa) on CCA-treated panels. Other species were present in similar numbers on panels of all treatments. Results indicate that there are no detrimental toxic effects to epibiota caused by the presence of CCA preservative within the matrix of the wood at any of the treatment levels. Differences in community structure between CCA-treated and untreated panels may be due to enhanced larval settlement on CCA-treated timber by some species as a result of modifications to the surface properties of the timber by the CCA preservative.

  16. Major transitions in the evolution of early land plants: a bryological perspective.

    PubMed

    Ligrone, Roberto; Duckett, Jeffrey G; Renzaglia, Karen S

    2012-04-01

    Background Molecular phylogeny has resolved the liverworts as the earliest-divergent clade of land plants and mosses as the sister group to hornworts plus tracheophytes, with alternative topologies resolving the hornworts as sister to mosses plus tracheophytes less well supported. The tracheophytes plus fossil plants putatively lacking lignified vascular tissue form the polysporangiophyte clade. Scope This paper reviews phylogenetic, developmental, anatomical, genetic and paleontological data with the aim of reconstructing the succession of events that shaped major land plant lineages. Conclusions Fundamental land plant characters primarily evolved in the bryophyte grade, and hence the key to a better understanding of the early evolution of land plants is in bryophytes. The last common ancestor of land plants was probably a leafless axial gametophyte bearing simple unisporangiate sporophytes. Water-conducting tissue, if present, was restricted to the gametophyte and presumably consisted of perforate cells similar to those in the early-divergent bryophytes Haplomitrium and Takakia. Stomata were a sporophyte innovation with the possible ancestral functions of producing a transpiration-driven flow of water and solutes from the parental gametophyte and facilitating spore separation before release. Stomata in mosses, hornworts and polysporangiophytes are viewed as homologous, and hence these three lineages are collectively referred to as the 'stomatophytes'. An indeterminate sporophyte body (the sporophyte shoot) developing from an apical meristem was the key innovation in polysporangiophytes. Poikilohydry is the ancestral condition in land plants; homoiohydry evolved in the sporophyte of polysporangiophytes. Fungal symbiotic associations ancestral to modern arbuscular mycorrhizas evolved in the gametophytic generation before the separation of major present-living lineages. Hydroids are imperforate water-conducting cells specific to advanced mosses. Xylem vascular cells

  17. Structure and Properties of Nanomaterials: From Inorganic Boron Nitride Nanotubes to the Calcareous Biomineralized Tubes of H. dianthus

    NASA Astrophysics Data System (ADS)

    Tanur, Adrienne Elizabeth

    Several nanomaterials systems, both inorganic and organic in nature, have been extensively investigated by a number of characterization techniques including atomic force microscopy (AFM), electron microscopy, Fourier transform infrared spectroscopy (FTIR), and energy dispersive x-ray spectroscopy (EDX). The first system consists of boron nitride nanotubes (BNNTs) synthesized via two different methods. The first method, silica-assisted catalytic chemical vapour deposition (SA-CVD), produced boron nitride nanotubes with different morphologies depending on the synthesis temperature. The second method, growth vapour trapping chemical vapour deposition (GVT-CVD), produced multiwall boron nitride nanotubes (MWBNNTs). The bending modulus of individual MWBNNTs was determined using an AFM three-point bending technique, and was found to be diameter-dependent due to the presence of shear effects. The second type of nanomaterial investigated is the biomineralized calcareous shell of the serpulid Hydroides dianthus. This material was found to be an inorganic-organic composite material composed of two different morphologies of CaCO3, collagen, and carboxylated and sulphated polysaccharides. The organic components were demonstrated to mediate the mineralization of CaCO3 in vitro. The final system studied is the proteinaceous cement of the barnacle Amphibalanus amphitrite. The secondary structure of the protein components was investigated via FTIR, revealing the presence of beta-sheet conformation, and nanoscale rod-shaped structures within the cement were identified as beta-sheet containing amyloid fibrils via chemical staining. These rod-shaped structures exhibited a stiffer nature compared with other structures in the adhesive, as measured by AFM nanoindentation.

  18. The Hidden Diversity of Zanclea Associated with Scleractinians Revealed by Molecular Data.

    PubMed

    Montano, Simone; Maggioni, Davide; Arrigoni, Roberto; Seveso, Davide; Puce, Stefania; Galli, Paolo

    2015-01-01

    Scleractinian reef corals have recently been acknowledged as the most numerous host group found in association with hydroids belonging to the Zanclea genus. However, knowledge of the molecular phylogenetic relationships among Zanclea species associated with scleractinians is just beginning. This study, using the nuclear 28S rDNA region and the fast-evolving mitochondrial 16S rRNA and COI genes, provides the most comprehensive phylogenetic reconstruction of the genus Zanclea with a particular focus on the genetic diversity among Zanclea specimens associated with 13 scleractinian genera. The monophyly of Zanclea associated with scleractinians was strongly supported in all nuclear and mitochondrial phylogenetic reconstructions. Furthermore, a combined mitochondrial 16S and COI phylogenetic tree revealed a multitude of hidden molecular lineages within this group (Clades I, II, III, V, VI, VII, and VIII), suggesting the existence of both host-generalist and genus-specific lineages of Zanclea associated with scleractinians. In addition to Z. gallii living in association with the genus Acropora, we discovered four well-supported lineages (Clades I, II, III, and VII), each one forming a strict association with a single scleractinian genus, including sequences of Zanclea associated with Montipora from two geographically separated areas (Maldives and Taiwan). Two host-generalist Zanclea lineages were also observed, and one of them was formed by Zanclea specimens symbiotic with seven scleractinian genera (Clade VIII). We also found that the COI gene allows the recognition of separated hidden lineages in agreement with the commonly recommended mitochondrial 16S as a DNA barcoding gene for Hydrozoa and shows reasonable potential for phylogenetic and evolutionary analyses in the genus Zanclea. Finally, as no DNA sequences are available for the majority of the nominal Zanclea species known, we note that they will be necessary to elucidate the diversity of the Zanclea

  19. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria

    PubMed Central

    Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Ikebe, Chiho; Watling, Les; Smith, Craig R; Glover, Adrian G

    2016-01-01

    Abstract Background We present data from a DNA taxonomy register of the abyssal Cnidaria collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. This is the second paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Data were collected from the UK-1 exploration area following the methods described in Glover et al. (2015b). New information Morphological and genetic data are presented for 10 species and 18 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 2 primnoid octocorals, 2 isidid octocorals, 1 anemone, 4 hydroids (including 2 pelagic siphonophores accidentally caught) and a scyphozoan jellyfish (in the benthic stage of the life cycle). Two taxa matched previously published genetic sequences (pelagic siphonophores), two taxa matched published morphological descriptions (abyssal primnoids described from the same locality in 2015) and the remaining 6 taxa are potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. We have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. For some of the specimens we also provide image data collected at the seabed by ROV, wich may facilitate more accurate taxon designation in coming ROV or AUV surveys. PMID:27660533

  20. Worldwide revision of the genus Fraseroscyphus Boero and Bouillon, 1993 (Cnidaria: Hydrozoa): an integrative approach to establish new generic diagnoses.

    PubMed

    Song, Xikun; Xiao, Zefeng; Gravili, Cinzia; Ruthensteiner, Bernhard; Mackenzie, Melanie; Wang, Shaoqing; Chen, Jinjing; Yu, Nan; Wang, Jianjun

    2016-09-14

    The morphological character of the hydrocladium and gonotheca origin from within the hydrothecal cavity has rarely been applied for generic diagnoses in hydrozoans. Its taxonomic value has been controversial for more than a century. The genus Fraseroscyphus Boero and Bouillon, 1993 (Hydrozoa: Sertulariidae) is a relatively recently debated case and it has been distinguished from Symplectoscyphus Marktanner-Turneretscher, 1890 based on this character. A review of this character in all published nominal species of the family Sertulariidae reveals that its occurrence is inconsistent at the genus level. However, phylogenetic analyses based on mitochondrial (16S) and nuclear (18S, 28S) genes support the position of Fraseroscyphus as a genus within the family Symplectoscyphidae Maronna et al., 2016. Comparisons of 16 morphological characters of 10 related species support the distinction of Fraseroscyphus from Antarctoscyphus and Symplectoscyphus by other characters in addition to the hydrocladial and gonothecal origin character. These new characters include the rarely-branched hydrocaulus, the absence of an apophysis, and the absence of an axillary hydrotheca. Furthermore, a revision based on the morphological character complex mentioned above using type and topotypic material, demonstrated that Sertularella sinuosa Fraser, 1948 (type species of Fraseroscyphus) and Symplectoscyphus huanghaiensis Tang & Huang, 1986 are junior synonyms of F. hozawai (Stechow, 1931) comb. nov. The assignment of Sertularella irregularis Trebilcock, 1928 and Sertularella macrogona Trebilcock, 1928 to Fraseroscyphus is also supported. In addition, sequence polymorphism of mitochondrial genes even within a single hydroid fragment was detected by the molecular cloning method, and is probably in part attributable to errors introduced by PCR, mitochondrial heteroplasmy and/or nuclear mitochondrial DNA (NUMTs). The adoption of the cloning method may be crucial to improve the sequence accuracy for

  1. Sessile and mobile components of a benthic ecosystem display mixed trends within a temperate marine reserve.

    PubMed

    Howarth, Leigh M; Pickup, Sarah E; Evans, Lowri E; Cross, Tim J; Hawkins, Julie P; Roberts, Callum M; Stewart, Bryce D

    2015-06-01

    Despite recent efforts to increase the global coverage of marine protected areas (MPAs), studies investigating the effectiveness of marine protected areas within temperate waters remain scarce. Furthermore, out of the few studies published on MPAs in temperate waters, the majority focus on specific ecological or fishery components rather than investigating the ecosystem as a whole. This study therefore investigated the dynamics of both benthic communities and fish populations within a recently established, fully protected marine reserve in Lamlash Bay, Isle of Arran, United Kingdom, over a four year period. A combination of photo and diver surveys revealed live maerl (Phymatolithon calcareum), macroalgae, sponges, hydroids, feather stars and eyelash worms (Myxicola infundibulum) to be significantly more abundant within the marine reserve than on surrounding fishing grounds. Likewise, the overall composition of epifaunal communities in and outside the reserve was significantly different. Both results are consistent with the hypothesis that protecting areas from fishing can encourage seafloor habitats to recover. In addition, the greater abundance of complex habitats within the reserve appeared to providing nursery habitat for juvenile cod (Gadus morhua) and scallops (Pecten maximus and Aequipecten opercularis). In contrast, there was little difference in the abundance of mobile benthic fauna, such as crabs and starfish, between the reserve and outside. Similarly, the use of baited underwater video cameras revealed no difference in the abundance and size of fish between the reserve and outside. Limited recovery of these ecosystem components may be due to the relatively small size (2.67 km(2)) and young age of the reserve (<5 years), both of which might have limited the extent of any benefits afforded to mobile fauna and fish communities. Overall, this study provides evidence that fully protected marine reserves can encourage seafloor habitats to recover, which in

  2. Genomic insights into the evolutionary origin of Myxozoa within Cnidaria

    PubMed Central

    Chang, E. Sally; Neuhof, Moran; Rubinstein, Nimrod D.; Diamant, Arik; Philippe, Hervé; Huchon, Dorothée; Cartwright, Paulyn

    2015-01-01

    The Myxozoa comprise over 2,000 species of microscopic obligate parasites that use both invertebrate and vertebrate hosts as part of their life cycle. Although the evolutionary origin of myxozoans has been elusive, a close relationship with cnidarians, a group that includes corals, sea anemones, jellyfish, and hydroids, is supported by some phylogenetic studies and the observation that the distinctive myxozoan structure, the polar capsule, is remarkably similar to the stinging structures (nematocysts) in cnidarians. To gain insight into the extreme evolutionary transition from a free-living cnidarian to a microscopic endoparasite, we analyzed genomic and transcriptomic assemblies from two distantly related myxozoan species, Kudoa iwatai and Myxobolus cerebralis, and compared these to the transcriptome and genome of the less reduced cnidarian parasite, Polypodium hydriforme. A phylogenomic analysis, using for the first time to our knowledge, a taxonomic sampling that represents the breadth of myxozoan diversity, including four newly generated myxozoan assemblies, confirms that myxozoans are cnidarians and are a sister taxon to P. hydriforme. Estimations of genome size reveal that myxozoans have one of the smallest reported animal genomes. Gene enrichment analyses show depletion of expressed genes in categories related to development, cell differentiation, and cell–cell communication. In addition, a search for candidate genes indicates that myxozoans lack key elements of signaling pathways and transcriptional factors important for multicellular development. Our results suggest that the degeneration of the myxozoan body plan from a free-living cnidarian to a microscopic parasitic cnidarian was accompanied by extreme reduction in genome size and gene content. PMID:26627241

  3. PSP toxin levels and plankton community composition and abundance in size-fractionated vertical profiles during spring/summer blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine and on Georges Bank, 2007, 2008, and 2010: 2. Plankton community composition and abundance

    PubMed Central

    Petitpas, Christian M.; Turner, Jefferson T.; Deeds, Jonathan R.; Keafer, Bruce A.; McGillicuddy, Dennis J.; Milligan, Peter J.; Shue, Vangie; White, Kevin D.; Anderson, Donald M.

    2015-01-01

    As part of the Gulf of Maine Toxicity (GOMTOX1) project, we determined Alexandrium fundyense abundance, paralytic shellfish poisoning (PSP) toxin levels in various plankton size fractions, and the community composition of potential grazers of A. fundyense in plankton size fractions during blooms of this toxic dinoflagellate in the coastal Gulf of Maine and on Georges Bank in spring and summer of 2007, 2008, and 2010. PSP toxins and A. fundyense cells were found throughout the sampled water column (down to 50 m) in the 20–64 μm size fractions. While PSP toxins were widespread throughout all size classes of the zooplankton grazing community, the majority of the toxin was measured in the 20–64 μm size fraction. A. fundyense cellular toxin content estimated from field samples was significantly higher in the coastal Gulf of Maine than on Georges Bank. Most samples containing PSP toxins in the present study had diverse assemblages of grazers. However, some samples clearly suggested PSP toxin accumulation in several different grazer taxa including tintinnids, heterotrophic dinoflagellates of the genus Protoperidinium, barnacle nauplii, the harpacticoid copepod Microsetella norvegica, the calanoid copepods Calanus finmarchicus and Pseudocalanus spp., the marine cladoceran Evadne nordmanni, and hydroids of the genus Clytia. Thus, a diverse assemblage of zooplankton grazers accumulated PSP toxins through food-web interactions. This raises the question of whether PSP toxins pose a potential human health risk not only from nearshore bivalve shellfish, but also potentially from fish and other upper-level consumers in zooplankton-based pelagic food webs. PMID:26236112

  4. Methane seepage effects on biodiversity and biological traits of macrofauna inhabiting authigenic carbonates

    NASA Astrophysics Data System (ADS)

    Levin, Lisa A.; Mendoza, Guillermo F.; Grupe, Benjamin M.

    2017-03-01

    Authigenic carbonate rocks at methane seeps are recognized as hosting diverse and abundant invertebrate assemblages, with potential forcing from fluid seepage and hydrography. Mensurative studies of carbonate macrofauna (>0.3 mm) at Hydrate Ridge, OR revealed little effect of water depth and overlying oxygenation (at 600 m and 800 m) but a large influence of seepage activity on density, taxonomic composition, diversity, and biological traits (feeding, lifestyle, motility, size and calcification). Rocks exposed to active seepage had 3-4× higher total macrofaunal densities than under inactive conditions. Assemblages exhibited higher species richness and reduced evenness (greater dominance) under active seepage than inactive conditions, but no difference in H‧ or rarefaction diversity. Actively seeping sites were characterized by errant (motile), bacterial grazing, small- and medium-sized, heavily calcified species, whereas inactive sites exhibited a greater diversity of feeding modes and more burrowers, sessile, large and lightly calcified species. Active rocks supported more exogonid (Syllidae), ampharetid, and cirratulid polychaetes, provannid snails, pyropeltid limpets, nemerteans, and sponges; whereas inactive rocks supported higher densities of ophiuroids, isopods, gammarid amphipods, hydroids, Typosyllis (Syllidae) and tanaids. Transplant experiments, in which rocks were transferred between active and inactive sites at Hydrate Ridge North (600 m), revealed that assemblages respond within 13 months to increase or cessation of seepage, taking on the feeding, size and calcification characteristics of the background fauna at the new site. Lifestyles and motility patterns shifted more slowly as the sessile, attached species did not track seepage as quickly. Provannid snails and pyropeltid limpets rapidly colonized rocks transplanted to active sites and disappeared when transplanted to inactive sites. Given the known variability of fluid fluxes and rapid community

  5. Two types of bilateral symmetry in the Metazoa: chordate and bilaterian.

    PubMed

    Jefferies, R P

    1991-01-01

    The chordate sagittal plane is perpendicular to the sagittal plane primitive for the bilaterally symmetrical metazoans (Bilateria). The earliest metazoans, when symmetrical at all, were probably radial in symmetry. The axis of symmetry was vertical and the mouth, when present, opened either upward or downward. The Bilateria evolved from the primitive metazoan condition by acquiring bilateral symmetry, mesoderm, a brain at the anterior end and protonephridia. Perhaps in the stem lineage of the Bilateria a hydroid-like or medusoid-like ancestor fell over on one side onto a substrate (pleurothetism). If so, the anteroposterior axis of Bilateria would be homologous with the vertical axis of radial symmetry in coelenterates. The bilaterian plane of symmetry arose to include the anteroposterior axis. The Deuterostomia (the Hemichordata, Echinodermata and Chordata) evolved within the Bilateria by producing the mouth as a secondary perforation. Within the deuterostomes the echinoderms and chordates constitute a monophyletic group named Dexiothetica. Hemichordates retain the primitive bilaterian sagittal plane. The Dexiothetica derive from an ancestor like the present-day hemichordate Cephalodiscus which had lain down on the primitive right side (dexiothetism) and acquired a calcite skeleton. The echinoderms evolved from this ancestor by losing the ancestral locomotory tail and gill slit, becoming static, moving the mouth to the centre of the new upper surface and developing radial pentameral symmetry. The chordates evolved from the same ancestor by developing a notochord in the tail, losing the water vascular system, evolving a filter-feeding pharynx and developing a new vertical plane of bilateral symmetry perpendicular to the old bilaterian plane. Evidence derived from certain bizarre Palaeozoic marine fossils (calcichordates) gives a detailed history of the early evolution of echinoderms and chordates and shows how the new bilateral symmetry was gradually acquired in

  6. Genomic insights into the evolutionary origin of Myxozoa within Cnidaria.

    PubMed

    Chang, E Sally; Neuhof, Moran; Rubinstein, Nimrod D; Diamant, Arik; Philippe, Hervé; Huchon, Dorothée; Cartwright, Paulyn

    2015-12-01

    The Myxozoa comprise over 2,000 species of microscopic obligate parasites that use both invertebrate and vertebrate hosts as part of their life cycle. Although the evolutionary origin of myxozoans has been elusive, a close relationship with cnidarians, a group that includes corals, sea anemones, jellyfish, and hydroids, is supported by some phylogenetic studies and the observation that the distinctive myxozoan structure, the polar capsule, is remarkably similar to the stinging structures (nematocysts) in cnidarians. To gain insight into the extreme evolutionary transition from a free-living cnidarian to a microscopic endoparasite, we analyzed genomic and transcriptomic assemblies from two distantly related myxozoan species, Kudoa iwatai and Myxobolus cerebralis, and compared these to the transcriptome and genome of the less reduced cnidarian parasite, Polypodium hydriforme. A phylogenomic analysis, using for the first time to our knowledge, a taxonomic sampling that represents the breadth of myxozoan diversity, including four newly generated myxozoan assemblies, confirms that myxozoans are cnidarians and are a sister taxon to P. hydriforme. Estimations of genome size reveal that myxozoans have one of the smallest reported animal genomes. Gene enrichment analyses show depletion of expressed genes in categories related to development, cell differentiation, and cell-cell communication. In addition, a search for candidate genes indicates that myxozoans lack key elements of signaling pathways and transcriptional factors important for multicellular development. Our results suggest that the degeneration of the myxozoan body plan from a free-living cnidarian to a microscopic parasitic cnidarian was accompanied by extreme reduction in genome size and gene content.

  7. Cnidarian phylogenetic relationships as revealed by mitogenomics.

    PubMed

    Kayal, Ehsan; Roure, Béatrice; Philippe, Hervé; Collins, Allen G; Lavrov, Dennis V

    2013-01-09

    Cnidaria (corals, sea anemones, hydroids, jellyfish) is a phylum of relatively simple aquatic animals characterized by the presence of the cnidocyst: a cell containing a giant capsular organelle with an eversible tubule (cnida). Species within Cnidaria have life cycles that involve one or both of the two distinct body forms, a typically benthic polyp, which may or may not be colonial, and a typically pelagic mostly solitary medusa. The currently accepted taxonomic scheme subdivides Cnidaria into two main assemblages: Anthozoa (Hexacorallia + Octocorallia) - cnidarians with a reproductive polyp and the absence of a medusa stage - and Medusozoa (Cubozoa, Hydrozoa, Scyphozoa, Staurozoa) - cnidarians that usually possess a reproductive medusa stage. Hypothesized relationships among these taxa greatly impact interpretations of cnidarian character evolution. We expanded the sampling of cnidarian mitochondrial genomes, particularly from Medusozoa, to reevaluate phylogenetic relationships within Cnidaria. Our phylogenetic analyses based on a mitochogenomic dataset support many prior hypotheses, including monophyly of Hexacorallia, Octocorallia, Medusozoa, Cubozoa, Staurozoa, Hydrozoa, Carybdeida, Chirodropida, and Hydroidolina, but reject the monophyly of Anthozoa, indicating that the Octocorallia + Medusozoa relationship is not the result of sampling bias, as proposed earlier. Further, our analyses contradict Scyphozoa [Discomedusae + Coronatae], Acraspeda [Cubozoa + Scyphozoa], as well as the hypothesis that Staurozoa is the sister group to all the other medusozoans. Cnidarian mitochondrial genomic data contain phylogenetic signal informative for understanding the evolutionary history of this phylum. Mitogenome-based phylogenies, which reject the monophyly of Anthozoa, provide further evidence for the polyp-first hypothesis. By rejecting the traditional Acraspeda and Scyphozoa hypotheses, these analyses suggest that the shared morphological characters in

  8. Major transitions in the evolution of early land plants: a bryological perspective

    PubMed Central

    Ligrone, Roberto; Duckett, Jeffrey G.; Renzaglia, Karen S.

    2012-01-01

    Background Molecular phylogeny has resolved the liverworts as the earliest-divergent clade of land plants and mosses as the sister group to hornworts plus tracheophytes, with alternative topologies resolving the hornworts as sister to mosses plus tracheophytes less well supported. The tracheophytes plus fossil plants putatively lacking lignified vascular tissue form the polysporangiophyte clade. Scope This paper reviews phylogenetic, developmental, anatomical, genetic and paleontological data with the aim of reconstructing the succession of events that shaped major land plant lineages. Conclusions Fundamental land plant characters primarily evolved in the bryophyte grade, and hence the key to a better understanding of the early evolution of land plants is in bryophytes. The last common ancestor of land plants was probably a leafless axial gametophyte bearing simple unisporangiate sporophytes. Water-conducting tissue, if present, was restricted to the gametophyte and presumably consisted of perforate cells similar to those in the early-divergent bryophytes Haplomitrium and Takakia. Stomata were a sporophyte innovation with the possible ancestral functions of producing a transpiration-driven flow of water and solutes from the parental gametophyte and facilitating spore separation before release. Stomata in mosses, hornworts and polysporangiophytes are viewed as homologous, and hence these three lineages are collectively referred to as the ‘stomatophytes’. An indeterminate sporophyte body (the sporophyte shoot) developing from an apical meristem was the key innovation in polysporangiophytes. Poikilohydry is the ancestral condition in land plants; homoiohydry evolved in the sporophyte of polysporangiophytes. Fungal symbiotic associations ancestral to modern arbuscular mycorrhizas evolved in the gametophytic generation before the separation of major present-living lineages. Hydroids are imperforate water-conducting cells specific to advanced mosses. Xylem vascular

  9. PSP toxin levels and plankton community composition and abundance in size-fractionated vertical profiles during spring/summer blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine and on Georges Bank, 2007, 2008, and 2010: 2. Plankton community composition and abundance.

    PubMed

    Petitpas, Christian M; Turner, Jefferson T; Deeds, Jonathan R; Keafer, Bruce A; McGillicuddy, Dennis J; Milligan, Peter J; Shue, Vangie; White, Kevin D; Anderson, Donald M

    2014-05-01

    As part of the Gulf of Maine Toxicity (GOMTOX) project, we determined Alexandrium fundyense abundance, paralytic shellfish poisoning (PSP) toxin levels in various plankton size fractions, and the community composition of potential grazers of A. fundyense in plankton size fractions during blooms of this toxic dinoflagellate in the coastal Gulf of Maine and on Georges Bank in spring and summer of 2007, 2008, and 2010. PSP toxins and A. fundyense cells were found throughout the sampled water column (down to 50 m) in the 20-64 μm size fractions. While PSP toxins were widespread throughout all size classes of the zooplankton grazing community, the majority of the toxin was measured in the 20-64 μm size fraction. A. fundyense cellular toxin content estimated from field samples was significantly higher in the coastal Gulf of Maine than on Georges Bank. Most samples containing PSP toxins in the present study had diverse assemblages of grazers. However, some samples clearly suggested PSP toxin accumulation in several different grazer taxa including tintinnids, heterotrophic dinoflagellates of the genus Protoperidinium, barnacle nauplii, the harpacticoid copepod Microsetella norvegica, the calanoid copepods Calanus finmarchicus and Pseudocalanus spp., the marine cladoceran Evadne nordmanni, and hydroids of the genus Clytia. Thus, a diverse assemblage of zooplankton grazers accumulated PSP toxins through food-web interactions. This raises the question of whether PSP toxins pose a potential human health risk not only from nearshore bivalve shellfish, but also potentially from fish and other upper-level consumers in zooplankton-based pelagic food webs.

  10. Biosynthesis, structure and biological activity of hydroxyeicosatetraenoic acids in Hydra vulgaris.

    PubMed Central

    Di Marzo, V; De Petrocellis, L; Gianfrani, C; Cimino, G

    1993-01-01

    Recent reports have suggested the involvement of arachidonic acid (AA) and its metabolites in the control of body pattern, head and tentacle regeneration and bud formation in Hydra spp. Here we describe for the first time the biosynthesis of hydroxyeicosatetraenoic acids (HETEs) in vitro by hydroid cytosolic extracts. Incubation of both unlabelled and tritiated AA with homogenates of Hydra vulgaris led to the conversion of up to 11% of the exogenous fatty acid into mainly two metabolites. These were characterized as 11-hydroperoxyeicosatetraenoic acid (11-HPETE) and 11-HETE by means of a combination of chromatographic, chemical, 1H-n.m.r. and electron-impact m.s. techniques. Trace amounts of 9-HETE and 12-HETE were also found. Analysis of 11-HETE by chiral-phase h.p.l.c. revealed that this metabolite was composed mainly of the R enantiomer. The production of 11-HPETE and 11-HETE was found to be: (1) associated with the cytosolic fraction of Hydra homogenates; (2) dependent on AA concentration, incubation time and protein amount in the homogenates; (3) unaffected by co-incubation with the 5- and 12-lipoxygenase inhibitors, 5,8,11-eicosatriynoic acid and nordihydroguaiaretic acid, the cyclo-oxygenase inhibitor, indomethacin, or the cytochrome P-450 inhibitors, proadifen and methoxalen. These results strongly suggest the presence of a very active (R)-11-lipoxygenase in H. vulgaris. The activity of both R and S enantiomers of synthetic 9-, 11- and 12-HETE and of 'endogenous' 11-HETE was studied on tentacle regeneration and bud formation in decapitated Hydra. Although almost all compounds tested inhibited budding, only endogenous 11-HETE and synthetic (R)-11-HETE significantly enhanced the average number of tentacles, thus suggesting that this eicosanoid might be one of the cellular regulators of regeneration in H. vulgaris. PMID:8216222

  11. Observations of the Columbia River salt wedge and estuarine turbidity maximum using AUVs

    NASA Astrophysics Data System (ADS)

    McNeil, C. L.; Shcherbina, A.; Litchendorf, T.; Sanford, T. B.; Martin, D.; Baptista, A. M.; Lopez, J.; Crump, B.

    2012-12-01

    We present detailed observations of the salt wedge and estuarine turbidity maxima (ETM) in the North Channel of the Columbia River estuary (OR, USA) under conditions of high river discharge during May 2012. Measurements were made using two REMUS-100 autonomous underwater vehicles (AUVs; Hydroid, Inc.) equipped with SBE-49 CTDs (Seabird-Electronics, Inc.) for water temperature and salinity, upward/downward looking ADCPs (Teledyne RDI, Inc.) for currents, and ECO Puck triplets (WET Labs, Inc.) for optical backscatter measurement of turbidity. The acoustic backscatter intensity from the ADCP was also used as a proxy measurement for suspended sediments and was found to correlate quite well with the optical backscatter measurements. Daily forecasts of tidal currents in the estuary were used to simulate the AUV path in advance of deployment to aid data collection. Repeat AUV sections were made along and across the channel during flood tide. The turbidity and height above riverbed of the bottom boundary layer was observed to increase toward the deeper waters at the center of the channel. An ETM-like feature was observed ahead of the advancing salt wedge front with locally higher turbidity levels, presumably the result of flocculation and resuspension. To visualize better the repeat section measurements we made data movies. Each frame of the movie is our best estimate of a synoptic snapshot of along-section tracer distribution at a given point in time. These snapshots were created by re-location of non-synoptic AUV measurements to account for the advection of water parcels. An example data movie showing the intrusion of the salt wedge during the flood tide will be presented.

  12. Epibenthic and mobile species colonisation of a geotextile artificial surf reef on the south coast of England

    PubMed Central

    Mallinson, Jenny; Hall, Alice E.; Pegg, Josephine; Ross, Kathryn; Clarke, Leo; Clements, Tom

    2017-01-01

    With increasing coastal infrastructure and use of novel materials there is a need to investigate the colonisation of assemblages associated with new structures, how these differ to natural and other artificial habitats and their potential impact on regional biodiversity. The colonisation of Europe’s first artificial surf reef (ASR) was investigated at Boscombe on the south coast of England (2009–2014) and compared with assemblages on existing natural and artificial habitats. The ASR consists of geotextile bags filled with sand located 220m offshore on a sandy sea bed at a depth of 0-5m. Successional changes in epibiota were recorded annually on differently orientated surfaces and depths using SCUBA diving and photography. Mobile faunal assemblages were sampled using Baited Remote Underwater Video (BRUV). Distinct stages in colonisation were observed, commencing with bryozoans and green algae which were replaced by red algae, hydroids and ascidians, however there were significant differences in assemblage structure with depth and orientation. The reef is being utilised by migratory, spawning and juvenile life-history stages of fish and invertebrates. The number of non-native species was larger than on natural reefs and other artificial habitats and some occupied a significant proportion of the structure. The accumulation of 180 benthic and mobile taxa, recorded to date, appears to have arisen from a locally rich and mixed pool of native and non-native species. Provided no negative invasive impacts are detected on nearby protected reefs the creation of novel yet diverse habitats may be considered a beneficial outcome. PMID:28926608

  13. The Hidden Diversity of Zanclea Associated with Scleractinians Revealed by Molecular Data

    PubMed Central

    Montano, Simone; Maggioni, Davide; Arrigoni, Roberto; Seveso, Davide; Puce, Stefania; Galli, Paolo

    2015-01-01

    Scleractinian reef corals have recently been acknowledged as the most numerous host group found in association with hydroids belonging to the Zanclea genus. However, knowledge of the molecular phylogenetic relationships among Zanclea species associated with scleractinians is just beginning. This study, using the nuclear 28S rDNA region and the fast-evolving mitochondrial 16S rRNA and COI genes, provides the most comprehensive phylogenetic reconstruction of the genus Zanclea with a particular focus on the genetic diversity among Zanclea specimens associated with 13 scleractinian genera. The monophyly of Zanclea associated with scleractinians was strongly supported in all nuclear and mitochondrial phylogenetic reconstructions. Furthermore, a combined mitochondrial 16S and COI phylogenetic tree revealed a multitude of hidden molecular lineages within this group (Clades I, II, III, V, VI, VII, and VIII), suggesting the existence of both host-generalist and genus-specific lineages of Zanclea associated with scleractinians. In addition to Z. gallii living in association with the genus Acropora, we discovered four well-supported lineages (Clades I, II, III, and VII), each one forming a strict association with a single scleractinian genus, including sequences of Zanclea associated with Montipora from two geographically separated areas (Maldives and Taiwan). Two host-generalist Zanclea lineages were also observed, and one of them was formed by Zanclea specimens symbiotic with seven scleractinian genera (Clade VIII). We also found that the COI gene allows the recognition of separated hidden lineages in agreement with the commonly recommended mitochondrial 16S as a DNA barcoding gene for Hydrozoa and shows reasonable potential for phylogenetic and evolutionary analyses in the genus Zanclea. Finally, as no DNA sequences are available for the majority of the nominal Zanclea species known, we note that they will be necessary to elucidate the diversity of the Zanclea

  14. Trophic versus structural effects of a marine foundation species, giant kelp (Macrocystis pyrifera).

    PubMed

    Miller, Robert J; Page, Henry M; Reed, Daniel C

    2015-12-01

    Foundation species create milieus in which ecosystems evolve, altering species abundances and distribution often to a dramatic degree. Although much descriptive work supports their importance, there remains little definitive information on the mechanisms by which foundation species alter their environment. These mechanisms fall into two basic categories: provision of food or other materials, and modification of the physical environment. Here, we manipulated the abundance of a marine foundation species, the giant kelp Macrocystis pyrifera, in 40 × 40-m plots at Mohawk Reef off Santa Barbara, California and found that its biomass had a strong positive effect on the abundance of bottom-dwelling sessile invertebrates. We examined the carbon (C) stable isotope values of seven species of sessile invertebrates in the treatment plots to test the hypothesis that this positive effect resulted from a nutritional supplement of small suspended particles of kelp detritus, as many studies have posited. We found no evidence from stable isotope analyses to support the hypothesis that kelp detritus is an important food source for sessile suspension-feeding invertebrates. The isotope composition of invertebrates varied with species and season, but was not affected by kelp biomass, with the exception of two species: the tunicate Styela montereyensis, which exhibited a slight enrichment in C stable isotope composition with increasing kelp biomass, and the hydroid Aglaophenia sp., which showed the opposite effect. These results suggest that modification of the physical habitat, rather than nutritional subsidy by kelp detritus, likely accounts for increased abundance of sessile invertebrates within giant kelp forests.

  15. Evolution of an ancient venom: recognition of a novel family of cnidarian toxins and the common evolutionary origin of sodium and potassium neurotoxins in sea anemone.

    PubMed

    Jouiaei, Mahdokht; Sunagar, Kartik; Federman Gross, Aya; Scheib, Holger; Alewood, Paul F; Moran, Yehu; Fry, Bryan G

    2015-06-01

    Despite Cnidaria (sea anemones, corals, jellyfish, and hydroids) being the oldest venomous animal lineage, structure-function relationships, phyletic distributions, and the molecular evolutionary regimes of toxins encoded by these intriguing animals are poorly understood. Hence, we have comprehensively elucidated the phylogenetic and molecular evolutionary histories of pharmacologically characterized cnidarian toxin families, including peptide neurotoxins (voltage-gated Na(+) and K(+) channel-targeting toxins: NaTxs and KTxs, respectively), pore-forming toxins (actinoporins, aerolysin-related toxins, and jellyfish toxins), and the newly discovered small cysteine-rich peptides (SCRiPs). We show that despite long evolutionary histories, most cnidarian toxins remain conserved under the strong influence of negative selection-a finding that is in striking contrast to the rapid evolution of toxin families in evolutionarily younger lineages, such as cone snails and advanced snakes. In contrast to the previous suggestions that implicated SCRiPs in the biomineralization process in corals, we demonstrate that they are potent neurotoxins that are likely involved in the envenoming function, and thus represent the first family of neurotoxins from corals. We also demonstrate the common evolutionary origin of type III KTxs and NaTxs in sea anemones. We show that type III KTxs have evolved from NaTxs under the regime of positive selection, and likely represent a unique evolutionary innovation of the Actinioidea lineage. We report a correlation between the accumulation of episodically adaptive sites and the emergence of novel pharmacological activities in this rapidly evolving neurotoxic clade. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Effects of CCA (copper-chrome-arsenic) preservative treatment of wood on the settlement and recruitment of barnacles and tube building polychaete worms.

    PubMed

    Brown, C J; Albuquerque, R M; Cragg, S M; Eaton, R A

    2000-01-01

    The effect of the anti-marine-borer treatment of wood using CCA (a pressure impregnated solution of copper, chromium and arsenic compounds) on non-target fouling animals was investigated. Panels treated to target retentions of 12, 24 and 48 kg CCA m(-3) of wood, together with untreated controls were exposed for 6, 12 and 18 months at coastal sites in Greece, Portugal, France and Sweden. General linear model (GLM) analysis revealed significant increases in numbers of certain fouling organisms (the serpulids Ficopomatus enig-maticus, Hydroides spp., Pomatoceros lamarkii and an unidentified species, three species of spirorbid, and the balanids Balanus perforatus and Elminius modestus) with increase in retention of CCA. The effect of CCA on the numbers of recruits may be due to effects on their settlement and survival, but may also be due to suppression of competitors. Significant differences in settlement density of barnacle spat occurred on newly exposed wood and on wood that had been exposed for 6 and 18 months. The relationships between settlement density and retention could be described by logarithmic curves of the form settlement density = a 1n(l + retention)+b. The effects of CCA on settlement are ascribed either to modification of wood surface chemistry leading to changes in surface charge, the availability of Cu, Cr or As at the wood surface, or to modifications to the microbial film. Barnacle settlement was between 6.5 and 14 times more intense on latewood than on earlywood, an effect that was evident in both untreated and preservative-treated wood.

  17. Evidence of micro-debris ingestion by Sargassum-associated fishes in the northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Vick, P.; Hernandez, F., Jr.; Muffelman, S.; Lestrade, O.

    2016-02-01

    Sargassum natans and S. fluitans collectively form a pelagic macroalgae complex (Sargassum) which is commonly found in surface waters of the Western-Central Atlantic Ocean (including the Gulf of Mexico). Mats and windrows of Sargassum support large and diverse assemblages of marine fishes and invertebrates, including many early life stages which use Sargassum as nursery areas. Sargassum is a near-surface habitat, and therefore is subject to oceanographic processes (e.g., Langmuir cells, frontal zones) that aggregate floating objects, including marine debris. Relatively little is known about the impacts of marine debris (which often gets broken down into "micro-debris") within Sargassum communities, although micro-debris particles may serve as vectors for toxic compounds if consumed by organisms. Here we present preliminary results from a pilot study examining the frequency of micro-debris occurrence in the stomachs of Sargassum-associated fishes. Neuston and plankton purse seine nets were used to collect Sargassum and associated fauna during surveys in the northern Gulf of Mexico (May, June and July 2014). Marine debris was present in all Sargassum collections, and ranged from relatively large items (e.g., soda bottles) to smaller particles (e.g., microplastics, monofilament threads). The associated fish community was dominated by relatively few taxa, including pipefishes, filefishes and the Sargassumfish, which collectively comprised approximately 85% of the total catch. Stomach contents from juvenile fishes contained mostly natural prey items, including copepods, small decapods, hydroids, and fishes. Micro-debris particles were observed in the stomachs of eight fish species, including juvenile Mahi Mahi, Planehead Filefish and Bermuda chub, among others. Overall, our initial observations suggest that there is some ingestion of micro-debris by fishes associated with Sargassum, although the frequency of occurrence is relatively low.

  18. Allorecognition proteins in an invertebrate exhibit homophilic interactions

    PubMed Central

    Karadge, Uma B.; Gosto, Minja; Nicotra, Matthew L.

    2015-01-01

    Summary Sessile colonial invertebrates—animals such as sponges, corals, bryozoans, and ascidians—can distinguish between their own tissues and those of conspecifics upon contact [1]. This ability, called allorecognition, mediates spatial competition and can prevent stem cell parasitism by ensuring that colonies only fuse with self or close kin. In every taxon studied to date, allorecognition is controlled by one or more highly polymorphic genes [2–8]. However, in no case is it understood how the proteins encoded by these genes discriminate self from non-self. In the cnidarian Hydractinia symbiolongicarpus, allorecognition is controlled by at least two highly polymorphic allorecognition genes, Alr1 and Alr2 [3, 5, 9–12]. Sequence variation at each gene predicts allorecognition in laboratory strains such that colonies reject if they do not share a common allele at either locus, fuse temporarily if they share an allele at only one locus, or fuse permanently if they share an allele at both genes [5, 9]. Here, we show that the gene products of Alr1 and Alr2 (Alr1 and Alr2) are self-ligands with extraordinary specificity. Using an in vitro cell aggregation assay, we found that Alr1 and Alr2 bind to themselves homophilically across opposing cell membranes. For both proteins, each isoform bound only to itself or to an isoform of nearly identical sequence. These results provide a mechanistic explanation for the exquisite specificity of Hydractinia allorecognition. Our results also indicate that hydroids have evolved a molecular strategy of self-recognition that is unique among characterized allorecognition systems within and outside invertebrates. PMID:26455308

  19. Inter-annual variability of the epibiotic community on Pagurus bernhardus from Scotland

    NASA Astrophysics Data System (ADS)

    Fernandez-Leborans, Gregorio; Gabilondo, Regina

    2006-01-01

    Epibiont communities of Pagurus bernhardus and its inhabiting shell collected in the same month of two consecutive years near the Isle of Cumbrae (Scotland) were analyzed. The epibionts found were: (1) the protozoans Acineta, Conchacineta, Corynophrya, Zoothamnium, Cothurnia mobiusi, Cothurnia longipes, Chilodochona, Cryptacineta, Ephelota gemmipara and Ephelota plana; (2) the hydrozoans Leuckartiara, Clytia and Phialella; (3) the entoproct Barentsia; (4) the cirripeds Balanus balanus and Balanus crenatus; (5) the polychaetes Pomatoceros triqueter, Circeis amoricana paguri and Hydroides norvegica. Among these epibionts, a protozoan ( E. plana), two hydrozoans ( Leuckartiara, and Phialella), and the entoproct ( Barentsia) have not been described previously as epibionts on crustaceans. The protozoan, entoproct and hydrozoan epibiont species found on P. bernhardus represent the first mention of their presence on this hermit crab. The protozoan epibionts were found only on the crab, while the hydrozoan epibionts were observed on the shell and on the crab. The cirriped species were observed only on the external surface of the shell, and the polychaete species were observed on the external and internal surfaces of the shell, although Circeis was found only internally. An analysis of the distribution and density of each epibiont species on the anatomical units of the crab, as well as on the different shell areas were made. The comparison between the data of the two years showed differences with respect to the size of crabs, diversity of epibiont groups and density of epibionts. There was a significant difference between the two years with respect to the distribution of epibionts on the anatomical units of the crab, both in terms of density and biomass. The influence of some environmental parameters on these differences is considered.

  20. The Natural Reservoirs of Salmonella Enteritidis in Populations of Wild Birds

    PubMed Central

    Obukhovska, Olga

    2013-01-01

    caspia, Phalacrocorax carbo, Podiceps cristatus, Anas platyrhynchos, Cygnus olar) revealed the presence of antibodies in blood serum (avarrage 17%) and egg yolks (avarrage 10%). From litter samples was isolated a great deal of Enterobacteria (Escherichia coli. Salmonella, Citrobacter, Enterobacter), havever 34.8% of them were Salmonella and near half of Salmonella (53.2%) was reprezentatives of serovar Salmonella Enteritidis. Conclusions It is proved that M. gallisepticum can persist among decorative waterfowl for her welfare with Galliformes, while waterfowl is a reservoir of the pathogen. Also natural reservoirs of Mycoplasma can be wild waterfowl (Casarca ferruginea). Such groups (populations) of birds may serve as a source of infection for commercial herds. This shows that wild waterfowl are the natural reservoir for these dangerous pathogens like Salmonella Enteritidis. The carriers may account for 17–18% of all individuals in the population. In nesting different species of wild birds may be infected by Salmonella Enteritidis. In the process of migrating wild birds can carry Salmonella Enteritidis over long distances and is a threat to commercial poultry flocks and humans.

  1. Species differences in the sensitivity of avian embryos to methylmercury

    USGS Publications Warehouse

    Heinz, G.H.; Hoffman, D.J.; Klimstra, J.D.; Stebbins, K.R.; Kondrad, S.L.; Erwin, C.A.

    2009-01-01

    We injected doses of methylmercury into the air cells of eggs of 26 species of birds and examined the dose-response curves of embryo survival. For 23 species we had adequate data to calculate the median lethal concentration (LC50). Based on the dose-response curves and LC50s, we ranked species according to their sensitivity to injected methylmercury. Although the previously published embryotoxic threshold of mercury in game farm mallards (Anas platyrhynchos) has been used as a default value to protect wild species of birds, we found that, relative to other species, mallard embryos are not very sensitive to injected methylmercury; their LC50 was 1.79 ug/g mercury on a wet-weight basis. Other species we categorized as also exhibiting relatively low sensitivity to injected methylmercury (their LC50s were 1 ug/g mercury or higher) were the hooded merganser (Lophodytes cucullatus), lesser scaup (Aythya affinis), Canada goose (Branta canadensis), double-crested cormorant (Phalacrocorax auritus), and laughing gull (Larus atricilla). Species we categorized as having medium sensitivity (their LC50s were greater than 0.25 ug/g mercury but less than 1 ug/g mercury) were the clapper rail (Rallus longirostris), sandhill crane (Grus canadensis), ring-necked pheasant (Phasianus colchicus), chicken (Gallus gallus), common grackle (Quiscalus quiscula), tree swallow (Tachycineta bicolor), herring gull (Larus argentatus), common tern (S terna hirundo), royal tern (Sterna maxima), Caspian tern (Sterna caspia), great egret (Ardea alba), brown pelican (Pelecanus occidentalis), and anhinga (Anhinga anhinga). Species we categorized as exhibiting high sensitivity (their LC50s were less than 0.25 ug/g mercury) were the American kestrel (Falco sparverius), osprey (Pandion haliaetus), white ibis (Eudocimus albus), snowy egret (Egretta thula), and tri-colored heron (Egretta tricolor). For mallards, chickens, and ring-necked pheasants (all species for which we could compare the toxicity of our

  2. Research, Monitoring, and Evaluation of Avian Predation on Salmonid Smolts in the Lower and Mid-Columbia River, 2006 Final Season Summary.

    SciTech Connect

    Roby, Daniel D.; Collis, Ken; Lyons, Donald E.

    2009-06-18

    This study investigates predation by piscivorous waterbirds on juvenile salmonids (Oncorhynchus spp.) from throughout the Columbia River Basin. During 2006, study objectives in the Columbia River estuary, work funded by the Bonneville Power Administration, were to (1) monitor and evaluate previous management initiatives to reduce Caspian tern (Hydroprogne caspia) predation on juvenile salmonids (smolts); (2) measure the impact of double-crested cormorant (Phalacrocorax auritus) predation on smolt survival, and assess potential management options to reduce cormorant predation; and (3) monitor large colonies of other piscivorous waterbirds in the estuary (i.e., glaucous-winged/western gulls [Larus glaucescens/occidentalis]) to determine the potential impacts on smolt survival. Study objectives on the mid-Columbia River, work funded by the Walla Walla District of the U.S. Army Corps of Engineers, were to (1) measure the impact of predation by Caspian terns and double-crested cormorants on smolt survival; and (2) monitor large nesting colonies of other piscivorous waterbirds (i.e., California gulls [L. californicus], ring-billed gulls [L. delawarensis], American white pelicans [Pelecanus erythrorhynchos]) on the mid-Columbia River to determine the potential for significant impacts on smolt survival. Our efforts to evaluate system-wide losses of juvenile salmonids to avian predation indicated that Caspian terns and double-crested cormorants were responsible for the vast majority of smolt losses to avian predators in the Columbia Basin, with most losses occurring in the Columbia River estuary. In 2006, East Sand Island in the Columbia River estuary supported the largest known breeding colonies of Caspian terns and double-crested cormorants in the world. The Caspian tern colony on East Sand Island consisted of about 9,200 breeding pairs in 2006, up slightly (but not significantly so) from the estimate of colony size in 2005 (8,820 pairs). There has not been a

  3. Response of the diatom flora in the Gdańsk Basin (southern Baltic Sea) to eutrophication in the last century

    NASA Astrophysics Data System (ADS)

    Witak, Małgorzata

    2016-04-01

    index nD=1.73). The analysis was performed with a NIKON microscope under a 100× oil immersion objective. The raw counts were transformed to relative abundance of the total frustules counted. The diatoms were divided into groups according to their biotype, salinity, trophy and saproby requirements. The content (in percentage) of all ecological groups were counted in the core. A total of 145 diatom species including varieties and forms representing 53 genera were identified in all samples. The diatom community was strong dominance by small-size planktic euhalobous (Thalassiosira levanderi, Pauliella taeniata) and mesohalobous (Cyclotella choctawhatcheeana) species. They were accompanied by freshwater eutraphentic and pollution-tolerant forms Actinocyclus normanii, Cyclostephanos dubius, Cyclotella atomus, C. caspia, C. meneghiniana, Stephanodiscus hantzschii, S. medius, S. neoastraea and S. parvus. The assemblage structure is a visible evidence of the progressive anthropopressure recorded in the near-bottom sediments of the Gdańsk Basin. Moreover, changes in spatial distribution of diatom anthropogenic assemblage show the close relationship to the distance from mouth of the Vistula River.

  4. Species differences in the sensitivity of avian embryos to methylmercury.

    PubMed

    Heinz, Gary H; Hoffman, David J; Klimstra, Jon D; Stebbins, Katherine R; Kondrad, Shannon L; Erwin, Carol A

    2009-01-01

    We injected doses of methylmercury into the air cells of eggs of 26 species of birds and examined the dose-response curves of embryo survival. For 23 species we had adequate data to calculate the median lethal concentration (LC(50)). Based on the dose-response curves and LC(50)s, we ranked species according to their sensitivity to injected methylmercury. Although the previously published embryotoxic threshold of mercury in game farm mallards (Anas platyrhynchos) has been used as a default value to protect wild species of birds, we found that, relative to other species, mallard embryos are not very sensitive to injected methylmercury; their LC(50 )was 1.79 microg/g mercury on a wet-weight basis. Other species we categorized as also exhibiting relatively low sensitivity to injected methylmercury (their LC(50)s were 1 microg/g mercury or higher) were the hooded merganser (Lophodytes cucullatus), lesser scaup (Aythya affinis), Canada goose (Branta canadensis), double-crested cormorant (Phalacrocorax auritus), and laughing gull (Larus atricilla). Species we categorized as having medium sensitivity (their LC(50)s were greater than 0.25 microg/g mercury but less than 1 microg/g mercury) were the clapper rail (Rallus longirostris), sandhill crane (Grus canadensis), ring-necked pheasant (Phasianus colchicus), chicken (Gallus gallus), common grackle (Quiscalus quiscula), tree swallow (Tachycineta bicolor), herring gull (Larus argentatus), common tern (Sterna hirundo), royal tern (Sterna maxima), Caspian tern (Sterna caspia), great egret (Ardea alba), brown pelican (Pelecanus occidentalis), and anhinga (Anhinga anhinga). Species we categorized as exhibiting high sensitivity (their LC(50)s were less than 0.25 microg/g mercury) were the American kestrel (Falco sparverius), osprey (Pandion haliaetus), white ibis (Eudocimus albus), snowy egret (Egretta thula), and tri-colored heron (Egretta tricolor). For mallards, chickens, and ring-necked pheasants (all species for which we

  5. Observations of recruitment and colonization by tunicates and associated invertebrates using giant one-meter2 recruitment plates at Woods Hole, Massachusetts

    USGS Publications Warehouse

    Valentine, Page C.; Carman, M.R.; Blackwood, Dann S.

    2016-01-01

    Large recruitment plates measuring 1 × 1 m were deployed over an 18-month period from September 2013 to March 2015 for the purpose of documenting recruitment and colonization processes of marine invertebrate species at Woods Hole, Massachusetts. Each side of two plates was subdivided into 16 subareas (25 × 25 cm), and an observational strategy was developed whereby, at approximately two-week intervals, a different subarea was cleaned. Using this approach, we were able to photographically document species recruitment and growth interactions. Water temperature records from the site show that steady warming and cooling between 3 and 20° C changed at a mean rate of 0.2 ° C d-1. However, temperature changes during the coolest and warmest parts of the temperature cycle were highly variable. In 2014, between the first and last occurrence of 0° C, temperatures were ≤0° C 15 percent of the time, but in 2015 temperatures were ≤0° C 93 percent of the time. In 2014, between the first and last occurrence of 21° C, temperatures were ≥21° C 88 percent of the time, and this warm period correlated with the disappearance of the hydroid Ectopleura crocea, the solitary tunicates Ascidiella aspersa and Ciona intestinalis, and the 2013 generation of Botrylloides violaceus. In Woods Hole, large plates provided enough space to accommodate both fast- and slow-colonizing species, resulting in the establishment of a diverse assemblage that was observed over a long time period. The most successful colonizing species had relatively long reproductive and recruitment periods, grew rapidly, repelled settlement onto their surfaces by larvae of any species, defended themselves against overgrowth by any species, overwintered, and lived a long time. Of the three dominant species observed in this study, the colonial tunicates Didemnum vexillum and Botrylloides violaceus had these qualities; the encrusting colonial bryozoan Schizoporella unicornis had all but one, it grew more slowly

  6. The role of containerships as transfer mechanisms of marine biofouling species.

    PubMed

    Davidson, Ian C; Brown, Christopher W; Sytsma, Mark D; Ruiz, Gregory M

    2009-10-01

    Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their submerged surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had submerged surface areas of >7000 m(2), and fouling coverage on this area was estimated to be <17 m(2) per vessel, with zero biota detected on the hulls of many vessels. The outlying smaller vessel (4465 m(2)) had an estimated coverage of 90% on the hull and also differed substantially from the other ships in terms of its recent voyage history, shorter voyage range and slower speeds. Despite the low extent of fouling, taxonomic richness was high among vessels. Consistent with recent studies, a wide range of organisms were concentrated at more protected and heterogeneous (non-hull) niche areas, including rudders, stern tubes and intake gratings. Green algae and barnacles were most frequently sampled among vessels, but hydroids, bryozoans, bivalves and ascidians were also recorded. One vessel had 20 different species in its fouling assemblage, including non-native species (already established in San Francisco Bay) and mobile species that were not detected in visual surveys. In contrast to other studies, dry dock block areas did not support many organisms, despite little

  7. First observations of the structure and megafaunal community of a large Lophelia reef on the Ghanaian shelf (the Gulf of Guinea)

    NASA Astrophysics Data System (ADS)

    Buhl-Mortensen, L.; Serigstad, B.; Buhl-Mortensen, P.; Olsen, M. N.; Ostrowski, M.; Błażewicz-Paszkowycz, M.; Appoh, E.

    2017-03-01

    The distribution of cold-water coral reefs is relatively well known in the North-east Atlantic as compared to the Central-east Atlantic, where only a few documentations exist from low latitudes. In 2012 an initial survey was conducted on a reef situated at 400 m depth on the continental shelf off Ghana. The reef corals and fauna were visually documented using a Video Assisted Multi Sampler (VAMS) coupled with an ROV. Here we present the results from three dives on the 1400 m long and 70 m high reef with an ambient temperatures between 9 and 10 °C. The banana shaped reef was oriented perpendicular to the main current, the convex side facing the current and there was no sign of human impact. The great height of the reef is probably a result of undisturbed growth for more than 20,000 years. On the Norwegian continental shelf the largest reefs are around 30 m high and have been aged to 9000 years. The reef morphology resembles that of Northeast Atlantic Lophelia reefs. The main reef building coral was Lophelia pertusa with contribution from Madrepora oculata, Solenosmilia variabilis, and occasional occurrences of Dendrophyllia cf. alternata. The skeleton of Aphrocallistes beatrix (Hexactinellidae) contributed to the reef framework and the reef consisted of 46% coral blocks 22% sediment, 13% coral rubble, 11% sponge skeleton and 8% live corals. A rich megafauna of 31 taxa was recorded and most frequent was Acesta excavate (bivalve), Aphrocallistes beatrix (with an associated Zooanthida on 39% of the colonies), squat lobsters, hydroids and bryozoans. Six fish species were recorded of which the Sebastidae Helicolenus dactylopterus and Nettastoma melanurum were found amongst coral blocks. The reef community showed several similarities with the northern reefs with sponges, Sebastes spp., squat lobsters, and Acesta excavata being common megafauna associates. In contrast the gorgonian corals that are characteristic of the northern reefs seemed to be lacking and

  8. High-resolution observations of plankton spatial distributions correlated with hydrography in the Great South Channel, Georges Bank

    NASA Astrophysics Data System (ADS)

    Gallager, Scott M.; Davis, Cabell S.; Epstein, Ari W.; Solow, Andy; Beardsley, Robert C.

    During a cruise to Georges Bank in May 1992, the Video Plankton Recorder (VPR) was towyoed while non-invasively obtaining images of the plankton and environmental (CTD) data. Data from an 8 h transect across the Great South Channel (GSC) were analyzed on a continuum of spatial scales from coarse-scale (100 km) to micro-scale (mm). Abundance was determined for 12 taxonomic groups including: invertebrate larvae (ophiopluteus larvae, anthozoa larvae: Cerianthus sp.), hydroids, copepods ( Calanus sp., Pseudocalanus sp.), pteropods ( Limacina retroversa, Clione sp.), ctenophores ( Mnemiopsis sp., Pleurobrachia sp.), larvacea ( Oikopleura sp.), chaetognatha ( Sagitta sp.), and diatom colonies ( Chaetoceros socialis). Species-specific plots of the positions of individual plankton in the water column and plots of the temperature and salinity at which the plankton were observed (temperature-salinity-plankton plots) showed that major taxonomic groups were patchy at coarse scales because of their association with specific water masses of different origin and associated temperature/density discontinuities (pycnocline and fronts). Analysis of the T- S characteristics of water types indicated that diatom colonies and ophiopluteus larvae of echinoderms were transported to GSC in a band of cold water originating on the south flank of Georges Bank. Within this band, diatom colonies formed an intense patch at a front reaching a density of 5 ml -1. Within each water mass, fine-scale (10s of meters) plankton patchiness was associated with regions of vertical stability as indicated by the association of plankton with regions of high gradient Richardson number. Aggregation of plankton at the microscale (<1 m) occurred significantly only for plankton capable of active swimming, suggesting a dynamic interaction between biological and physical variables at this spatial scale. On occasion, veliger larvae of Limacina retroversa were found in spawning patches at concentrations exceeding 600

  9. Biodiversity of the Deep-Sea Benthic Fauna in the Sangihe-Talaud Region, Indonesia: Observations from the INDEX-SATAL 2010 Expedition

    NASA Astrophysics Data System (ADS)

    Herrera, S.; Munro, C.; Nganro, N.; Tunnicliffe, V.; Wirasantosa, S.; Sibert, E.; Hammond, S. R.; Bors, E.; Butterfield, D.; Holden, J. F.; Baker, E. T.; Sherrin, J.; Makarim, S.; Troa, R.; Shank, T. M.

    2010-12-01

    The benthic ecosystems found in the deep-sea promontories of Sangihe Talaud region were explored, between June and August 2010, using the ROV Little Hercules aboard the NOAA ship Okeanos Explorer. The Sangihe-Talaud region is part of the Coral Triangle (CT) an area known for harboring the most biodiverse shallow-water coral reefs in the world. Notwithstanding the significant research efforts that have been undertaken to catalog and protect the biodiversity of the CT prior this expedition, virtually nothing was known about the life inhabiting the deep sea. The high-resolution imagery obtained from the 27 ROV dives revealed remarkably high abundances and diversity of animal species, many of which appear to be novel. On hard bottom substrates, cold-water corals were the dominant sessile macrofauna, in terms of biomass, followed by glass sponges (Hexactinellida) and sea lilies (Crinoidea). The coral taxa observed in this area represent six large orders of cnidarians: antipatharians (black corals), scleractinians (stony corals), zoanthideans (gold corals), alcyonaceans (octocorals), pennatulaceans (sea pens), and anthoathecates (hydrocorals). Most sessile species, independently of their size class or taxonomic affiliation, harbor a wide variety of associated fauna. Brittle stars (Ophiuroidea), squat lobsters (Galatheoidea), shrimp (Caridea), amphipods (Amphipoda), anemones (Actinaria), zanthideans, barnacles (Cirripedia), hydroids (Hydrozoa) and worms (Polychaeta) are the animal groups most commonly found forming these associations. In contrast, soft bottom habitats were dominated by stalked sponges, sea pens, sea cucumbers (Holothuroidea) and brittle stars. Other conspicuous fauna include fish, hermit crabs (Paguridae), urchins (Echinoidea) and octopuses (Cephalopoda). The abundance of habitats generated by the high number of geological and biological features and depth ranges present in the deep coral triangle (e.g., ridges, seamounts, island margins, plains, and rock

  10. Field-based experimental acidification alters fouling community structure and reduces diversity.

    PubMed

    Brown, Norah E M; Therriault, Thomas W; Harley, Christopher D G

    2016-09-01

    Increasing levels of CO2 in the atmosphere are affecting ocean chemistry, leading to increased acidification (i.e. decreased pH) and reductions in calcium carbonate saturation state. Many species are likely to respond to acidification, but the direction and magnitude of these responses will be based on interspecific and ontogenetic variation in physiology and the relative importance of calcification. Differential responses to ocean acidification (OA) among species will likely result in important changes in community structure and diversity. To characterize the potential impacts of OA on community composition and structure, we examined the response of a marine fouling community to experimental CO2 enrichment in field-deployed flow-through mesocosm systems. Acidification significantly altered the community structure by altering the relative abundance of species and reduced community variability, resulting in more homogenous biofouling communities from one experimental tile to the next both among and within the acidified mesocosms. Mussel (Mytilus trossulus) recruitment was reduced by over 30% in the elevated CO2 treatment compared to the ambient treatment by the end of the experiment. Strong differences in mussel cover (up to 40% lower in acidified conditions) developed over the second half of the 10-week experiment. Acidification did not appear to affect the mussel growth, as average mussel sizes were similar between treatments at the end of the experiment. Hydroid (Obelia dichotoma) cover was significantly reduced in the elevated CO2 treatment after 8 weeks. Conversely, the percentage cover of bryozoan colonies (Mebranipora membranacea) was higher under acidified conditions with differences becoming apparent after 6 weeks. Neither recruitment nor final size of barnacles (Balanus crenatus) was affected by acidification. By the end of the experiment, diversity was 41% lower in the acidified treatment relative to ambient conditions. Overall, our findings support the

  11. Geological and biological heterogeneity of the Aleutian margin (1965-4822 m)

    NASA Astrophysics Data System (ADS)

    Rathburn, A. E.; Levin, L. A.; Tryon, M.; Gieskes, J. M.; Martin, J. B.; Pérez, M. E.; Fodrie, F. J.; Neira, C.; Fryer, G. J.; Mendoza, G.; McMillan, P. A.; Kluesner, J.; Adamic, J.; Ziebis, W.

    2009-01-01

    clam bed, pogonophoran field and carbonate habitats. Seep foraminiferal assemblages were dominated by agglutinated taxa, except for habitats above the seafloor on pogonophoran tubes. Numerous infaunal taxa in clam bed and pogonophoran field sediments and deep-sea “reef” cnidarians (e.g., corals and hydroids) residing on rocks near seepage sites exhibited light organic δ 13C signatures indicative of chemosynthetic nutritional sources. The extensive geological, biogeochemical and biological heterogeneity as well as disturbance features observed on the Aleutian slope provide an attractive explanation for the exceptionally high biodiversity characteristic of the world’s continental margins.

  12. The vascular plants: open system of growth.

    PubMed

    Basile, Alice; Fambrini, Marco; Pugliesi, Claudio

    2017-03-01

    What is fascinating in plants (true also in sessile animals such as corals and hydroids) is definitely their open and indeterminate growth, as a result of meristematic activity. Plants as well as animals are characterized by a multicellular organization, with which they share a common set of genes inherited from a common eukaryotic ancestor; nevertheless, circa 1.5 billion years of evolutionary history made the two kingdoms very different in their own developmental biology. Flowering plants, also known as angiosperms, arose during the Cretaceous Period (145-65 million years ago), and up to date, they count around 235,000 species, representing the largest and most diverse group within the plant kingdom. One of the foundations of their success relies on the plant-pollinator relationship, essentially unique to angiosperms that pushed large speciation in both plants and insects and on the presence of the carpel, the structure devoted to seed enclosure. A seed represents the main organ preserving the genetic information of a plant; during embryogenesis, the primary axis of development is established by two groups of pluripotent cells: the shoot apical meristem (SAM), responsible for gene rating all aboveground organs, and the root apical meristem (RAM), responsible for producing all underground organs. During postembryonic shoot development, axillary meristem (AM) initiation and outgrowth are responsible for producing all secondary axes of growth including inflorescence branches or flowers. The production of AMs is tightly linked to the production of leaves and their separation from SAM. As leaf primordia are formed on the flanks of the SAM, a region between the apex and the developing organ is established and referred to as boundary zone. Interaction between hormones and the gene network in the boundary zone is fundamental for AM initiation. AMs only develop at the adaxial base of the leaf; thus, AM initiation is also strictly associated with leaf polarity. AMs

  13. Chronic Effects of Coated Silver Nanoparticles on Marine Invertebrate Larvae: A Proof of Concept Study

    PubMed Central

    Chan, Christine Ying Shan; Chiu, Jill Man Ying

    2015-01-01

    Silver nanoparticles (AgNPs), owing to their unique physical and chemical properties, have become increasingly popular in consumer products. However, data on their potential biological effects on marine organisms, especially invertebrates, remain very limited. This proof of principle study reports the chronic sub-lethal toxicity of two coated AgNPs (oleic acid coated AgNPs and polyvinylpyrrolidone coated AgNPs) on marine benthic invertebrate larvae across three phyla (i.e., the barnacle Balanus Amphitrite, the slipper-limpet Crepidula onyx, and the polychaete Hydroides elegans) in terms of growth, development, and metamorphosis. Bioaccumulation and biodistribution of silver were also investigated. Larvae were also exposed to silver nitrate (AgNO3) in parallel to distinguish the toxic effects derived from nano-silver and the aqueous form of silver. The sub-lethal effect of chronic exposure to coated AgNPs resulted in a significant retardation in growth and development, and reduction of larval settlement rate. The larval settlement rate of H. elegans was significantly lower in the coated AgNP treatment than the AgNO3 treatment, suggesting that the toxicity of coated AgNPs might not be solely evoked by the release of silver ions (Ag+) in the test medium. The three species accumulated silver effectively from coated AgNPs as well as AgNO3, and coated AgNPs were observed in the vacuoles of epithelial cell in the digestive tract of C. onyx. Types of surface coatings did not affect the sub-lethal toxicity of AgNPs. This study demonstrated that coated AgNPs exerted toxic effects in a species-specific manner, and their exposure might allow bioaccumulation of silver, and affect growth, development, and settlement of marine invertebrate larvae. This study also highlighted the possibility that coated AgNPs could be taken up through diet and the toxicity of coated AgNPs might be mediated through toxic Ag+ as well as the novel modalities of coated AgNPs. PMID:26171857

  14. Baseline seabed habitat and biotope mapping for a proposed marine reserve.

    PubMed

    Lee, Sonny T M; Kelly, Michelle; Langlois, Tim J; Costello, Mark J

    2015-01-01

    Seabed mapping can quantify the extent of benthic habitats that comprise marine ecosystems, and assess the impact of fisheries on an ecosystem. In this study, the distribution of seabed habitats in a proposed no-take Marine Reserve along the northeast coast of Great Barrier Island, New Zealand, was mapped using underwater video combined with bathymetry and substratum data. As a result of the boundary extending to the 12 nautical mile Territorial Limit, it would have been the largest coastal Marine Reserve in the country. Recreational and commercial fisheries occur in the region and would be expected to affect species' abundance. The seabed of the study area and adjacent coastal waters has been trawled up to five times per year. Benthic communities were grouped by multivariate cluster analysis into four biotope classes; namely (1) shallow water macroalgae Ecklonia sp. and Ulva sp. on rocky substrata (Eck.Ulv); and deeper (2) diverse epifauna of sponges and bryozoans on rocky substrata (Por.Bry), (3) brittle star Amphiura sp. and sea anemone Edwardsia sp. on muddy sand (Amph.Edw), and (4) hydroids on mud (Hyd). In biotopes Por.Bry, Amph.Edw and Hyd, there where boulders and rocks were present, and diverse sponge, bryozoan and coral communities. Fifty species were recorded in the deep water survey including significant numbers of the shallow-water hexactinellid glass sponges Symplectella rowi Dendy, 1924 and Rossella ijimai Dendy, 1924, the giant pipe demosponge Isodictya cavicornuta Dendy, 1924, black corals, and locally endemic gorgonians. The habitats identified in the waters to the northeast of Great Barrier Island are likely to be representative of similar depth ranges in northeast New Zealand. This study provides a baseline of the benthic habitats so that should the area become a Marine Reserve, any habitat change might be related to protection from fishing activities and impacts, such as recovery of epifauna following cessation of trawling. The habitat map may

  15. Baseline seabed habitat and biotope mapping for a proposed marine reserve

    PubMed Central

    Kelly, Michelle; Langlois, Tim J.; Costello, Mark J.

    2015-01-01

    Seabed mapping can quantify the extent of benthic habitats that comprise marine ecosystems, and assess the impact of fisheries on an ecosystem. In this study, the distribution of seabed habitats in a proposed no-take Marine Reserve along the northeast coast of Great Barrier Island, New Zealand, was mapped using underwater video combined with bathymetry and substratum data. As a result of the boundary extending to the 12 nautical mile Territorial Limit, it would have been the largest coastal Marine Reserve in the country. Recreational and commercial fisheries occur in the region and would be expected to affect species’ abundance. The seabed of the study area and adjacent coastal waters has been trawled up to five times per year. Benthic communities were grouped by multivariate cluster analysis into four biotope classes; namely (1) shallow water macroalgae Ecklonia sp. and Ulva sp. on rocky substrata (Eck.Ulv); and deeper (2) diverse epifauna of sponges and bryozoans on rocky substrata (Por.Bry), (3) brittle star Amphiura sp. and sea anemone Edwardsia sp. on muddy sand (Amph.Edw), and (4) hydroids on mud (Hyd). In biotopes Por.Bry, Amph.Edw and Hyd, there where boulders and rocks were present, and diverse sponge, bryozoan and coral communities. Fifty species were recorded in the deep water survey including significant numbers of the shallow-water hexactinellid glass sponges Symplectella rowi Dendy, 1924 and Rossella ijimai Dendy, 1924, the giant pipe demosponge Isodictya cavicornuta Dendy, 1924, black corals, and locally endemic gorgonians. The habitats identified in the waters to the northeast of Great Barrier Island are likely to be representative of similar depth ranges in northeast New Zealand. This study provides a baseline of the benthic habitats so that should the area become a Marine Reserve, any habitat change might be related to protection from fishing activities and impacts, such as recovery of epifauna following cessation of trawling. The habitat map

  16. Recolonization of gravel habitats on Georges Bank (northwest Atlantic)

    USGS Publications Warehouse

    Collie, J.S.; Hermsen, J.M.; Valentine, P.C.

    2009-01-01

    Gravel habitats on continental shelves around the world support productive fisheries but are also vulnerable to disturbance from bottom fishing. We conducted a 2-year in situ experiment to measure the rate of colonization of a gravel habitat on northern Georges Bank in an area closed to fishing (Closed Area II) since December 1994. Three large (0.25 m2) sediment trays containing defaunated pebble gravel were deployed at a study site (47 m water depth) in July 1997 and recovered in June 1999. The undersides of the tray lids positioned 56 cm above the trays served as settlement panels over the same time period. We observed rapid colonization of the gravel substrate (56 species) and the settlement panels (35 species), indicating that colonization of gravel in this region is not limited by the supply of colonists. The species composition of the taxa found in the trays was broadly similar to that we collected over a 10-year period (1994-2004) in dredge samples from gravel sediments at the same site. The increase in abundance of animals in the gravel colonization trays was rapid and reached a level in 2 years that took 4.5 years to achieve in the surrounding gravel sediments once fishing had stopped, based on data from dredge sampling at this site. The increase in biomass of animals found in the sediment trays paralleled the trend of biomass increase observed in dredge samples over the same period (1997-1999) but was lower in value. These data suggest that after rapid initial increase in abundance of organisms, succession proceeded by increasing individual body size. A comparison of settlement panel and tray faunas revealed that the mean biomass of structure-forming epifauna (sponges, bryozoans, anemones, hydroids, colonial tube worms) on the panels was 8 times that found on the trays. Structure-forming taxa constituted 29% of the mean biomass of the panel fauna but only 5.5% of the tray fauna. By contrast, the mean biomass of scavengers (crabs, echinoderms, nudibranchs

  17. The influence of freshwater and material export on sedimentary facies and benthic processes within the Fly Delta and adjacent Gulf of Papua (Papua New Guinea)

    NASA Astrophysics Data System (ADS)

    Alongi, D. M.; Christoffersen, P.; Tirendi, F.; Robertson, A. I.

    1992-02-01

    cm -2) and infauna (range: 86-5555 individuals m -2; 0.10-5.85 g AFDW m -2) were generally lower in the delta than in the gulf. The infauna was dominated by nematodes, copepods, foraminifera and small, tube-building, deposit- and suspension-feeding polychaetes and amphipods. Rates of bacterial productivity were very erratic with sediment depth across stations, ranging from 0-2108 mg C m -2 day -1 (DNA synthesis) and from 0-228 mg C m -2 day -1 (protein synthesis), respectively. Rates of benthic respiration and DOC flux across the sediment-water interface were generally high, ranging from 63-780 mg C m -2 day -1 and from -797 to 514 mg C m -2 day -1, respectively. Epibenthos were more diverse (at the phyletic level) at the mid-shelf than inshore, composed mainly of sponges, crabs, crinoids, echinoids, bivalves, hydroids and asteroids. Demersal nekton abundance was low, dominated by the leatherjacket, Paramonacanthus filicauda, the pony fish, Leiognathus splendens and the grunter, Pomadasys argyreus, suggesting limited transfer of infaunal biomass to higher trophic levels. The response of the benthic regime to the export of freshwater and material from the Fly River generally conforms to the RHOADSet al. [(1985) Continental Shelf Research, 4, 189-213] model of benthic response to effluent derived from the Changjiang River in the East China Sea and is similar to infaunal and sedimentary patterns off the Amazon. Nutrient release from the delta sediments contributes little to water-column production, but in the gulf, nutrient efflux from the benthos contributes, on average, 38 and 61% of the annual N and P requirements of phytoplankton production, reflecting closer benthic-pelagic coupling and enrichment of biological productivity in the Gulf of Papua due to nutrient export from the Fly River.

  18. Research, Monitoring, and Evaluation of Avian Predation on Salmonid Smolts in the Lower and Mid-Columbia River, 2008 Draft Season Summary.

    SciTech Connect

    Roby, Daniel D.; Collis, Ken; Lyons, Donald E.

    2009-07-08

    This report describes investigations into predation by piscivorous colonial waterbirds on juvenile salmonids (Oncorhynchus spp.) from throughout the Columbia River basin during 2008. East Sand Island in the Columbia River estuary again supported the largest known breeding colony of Caspian terns (Hydroprogne caspia) in the world (approximately 10,700 breeding pairs) and the largest breeding colony of double-crested cormorants (Phalacrocorax auritus) in western North America (approximately 10,950 breeding pairs). The Caspian tern colony increased from 2007, but not significantly so, while the double-crested cormorant colony experienced a significant decline (20%) from 2007. Average cormorant nesting success in 2008, however, was down only slightly from 2007, suggesting that food supply during the 2008 nesting season was not the principal cause of the decline in cormorant colony size. Total consumption of juvenile salmonids by East Sand Island Caspian terns in 2008 was approximately 6.7 million smolts (95% c.i. = 5.8-7.5 million). Caspian terns nesting on East Sand Island continued to rely primarily on marine forage fishes as a food supply. Based on smolt PIT tag recoveries on the East Sand Island Caspian tern colony, predation rates were highest on steelhead in 2008; minimum predation rates on steelhead smolts detected passing Bonneville Dam averaged 8.3% for wild smolts and 10.7% for hatchery-raised smolts. In 2007, total smolt consumption by East Sand Island double-crested cormorants was about 9.2 million juvenile salmonids (95% c.i. = 4.4-14.0 million), similar to or greater than that of East Sand Island Caspian terns during that year (5.5 million juvenile salmonids; 95% c.i. = 4.8-6.2 million). The numbers of smolt PIT tags recovered on the cormorant colony in 2008 were roughly proportional to the relative availability of PIT-tagged salmonids released in the Basin, suggesting that cormorant predation on salmonid smolts in the estuary was less selective than tern

  19. Long-term impact of bottom trawling on pelagic-benthic coupling in the southern North Sea (German Bight)

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; van Beusekom, Justus E. E.; Neumann, Andreas; Naderipour, Celine; Janssen, Felix; Ahmerkamp, Soeren; Holtappels, Moritz; Schueckel, Ulrike

    2016-04-01

    The southern North Sea, and the German Bight, has been systematically bottom-trawled at least since the late 19th century (Christiansen, 2009; Reiss et al., 2009; Kröncke 2011; Emeis et al., 2015, Neumann et al., 2016). As a result, benthic habitats and benthic biogenic structures created by bivalves, polychaetes and hydroids where destroyed or reduced. The parallel removal of hard substrate (gravel and boulders) avoids the resettlement of hard-substrate depended species. For example, the Oyster ground, a huge oyster bank a hundred years ago (Olsen, 1883), turned into a muddy depression today. In addition, shallow depth of max 40 m, strong tidal currents and frequent storms result in a high-energy environment with low sedimentation rates and recurrent sediment resuspension. The decrease in benthic filtering capacity by disturbance in epifauna and bottom roughness (Callaway et al., 2007) apparently influence pelagic-benthic coupling of biogeochemical fluxes. Heip et al. (1995) indicate that benthic respiration at depths prevailing in the German Bight accounts for 10-40% of total respiration, whereas pelagic respiration accounts for 60-90%. Previous estimates are in the middle of this range (Heip et al., 1995). To test these hypotheses and to assess the partitioning of benthic and pelagic processes, and the factors influencing organic matter mineralization, we measured pelagic production and respiration based on Winkler titration, in-situ benthic fluxes using chamber landers, we did ex-situ incubations of intact sediment cores and analysed still images from a towed benthic video sled. In addition, O2 fluxes in permeable sediments were estimated by integrating the volumetric rate measurements of the upper sediment layer over in-situ microsensor-measured O2 penetration depth. Our current results show significant seasonality in benthic respiration, with highest rates in summer and lowest rates in winter. No significant differences in total benthic respiration rates

  20. An observatory system for physical and biogeochemical parameters in the northern Adriatic Sea: the "Acqua Alta" oceanographic platform

    NASA Astrophysics Data System (ADS)

    Benetazzo, Alvise; Barbariol, Francesco; Bastianini, Mauro; Bergamasco, Andrea; Bergamasco, Filippo; Bernardi Aubry, Fabrizio; Bertotti, Luciana; Bonaldo, Davide; Cavaleri, Luigi; Carniel, Sandro; Falcieri, Francesco M.; Finotto, Stefania; Lester, Graham; Licer, Matjaz; Malacic, Vlado; Minuzzo, Tiziano; Sclavo, Mauro

    2015-04-01

    instance, during the 2014 cruise "CARPET" the Autonomous Underwater Vehicle REMUS-100 (Hydroid Inc.) and the turbulence profiler MSS-90 (a free-falling Micro Structure probe) were employed simultaneously in proximity of the tower, to define the winter conditions of the basin and to accurately track the plume regions of the rivers discharging into it.