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Sample records for proportioned intertidal barnacles

  1. Intertidal barnacles are not uniformly abundant around the coast of ...

    African Journals Online (AJOL)

    spamer

    Intertidal barnacles are significantly more abundant on the south than on the west ... California Coastal Commission, 3111 Camino del Rio North, Suite 200, San ..... factors that are likely to affect adult growth and sur- .... north-west coast of the U.S.A. (e.g. Dayton 1971, .... SHANNON, L. V. 1985 — The Benguela ecosystem.

  2. Recruitment of the Intertidal Barnacle Semibalanus balanoides; Metamorphosis and Survival from Daily to Seasonal Timescales

    Science.gov (United States)

    2008-09-01

    benthic habitat is the terminal destination for marine animals in terms of their reproductive lifecycle. Recruitment dynamics relating to seasonal...novel tool to address the role of seasonally changing influences in benthic marine invertebrate recruitment. p. 69...been exploited as an example of marine animal recruitment. The adult barnacle is sessile and does not move after the transition from the larval to

  3. Influence of upwelling and tropical environments on the breeding development of the intertidal barnacle Tetraclita stalactifera (Lamarck, 1818

    Directory of Open Access Journals (Sweden)

    Luis Felipe Skinner

    2011-12-01

    Full Text Available Cabo Frio, with its unique oceanographic conditions, is an important biogeographical transitional region between tropical and sub-tropical waters. This is due to the presence of upwelling from the Central Water of the South Atlantic (CWSA, and the presence of tropical waters from the Brazilian Current (BC and Coastal Water (CW. The intertidal barnacle, Tetraclita stalactifera, and its brooding stages were analyzed to correlate environmental conditions with reproductive development. Two thermal contrasting sites were chosen: Ponta da Cabeça (PC, which is under the influence of seasonal upwelling, and Ponta da Fortaleza (PF which experiences tropical influences. At each site, T. stalactifera specimens were collected monthly and their egg lamellae conditions classified into stages from 0 (empty to IV (ready to release. Our results show a seasonal effect on brooding at the PC site and a continuous development at the PF site. Nauplii larval availability also followed this trend. Differences between the sites could be due to ecological differences related to water temperature and the ecological-physiological response of the barnacles to these differences.Cabo Frio, devido suas características oceanográficas, causado pela é uma importante região biogeográfica transicional entre águas tropicais e sub-tropicais. Isto é ressurgência da Água Central do Atlântico Sul (ACAS e a presença de águas tropicais da Corrente do Brasil (CB e de Água Costeira (AC. A craca do mediolitoral Tetraclita stalactifera e seus estágios de maturação larval foram analisados a fim de serem correlacionados às condições ambientais. Dois locais com características termais contrastantes foram escolhidos: a Ponta da Cabeça (PC, que está sobre influência sazonal da ressurgência e a Ponta da Fortaleza (PF, sob influência da água tropical. Em cada local, indivíduos de T. stalactifera foram coletados mensalmente e a condição de suas lamellas ovígeras aferida

  4. Predicting free-space occupancy on novel artificial structures by an invasive intertidal barnacle using a removal experiment.

    Directory of Open Access Journals (Sweden)

    Sally A Bracewell

    Full Text Available Artificial structures can create novel habitat in the marine environment that has been associated with the spread of invasive species. They are often located in areas of high disturbance and can vary significantly in the area of free space provided for settlement of marine organisms. Whilst correlation between the amount of free space available and recruitment success has been shown in populations of several marine benthic organisms, there has been relatively little focus on invasive species, a group with the potential to reproduce in vast numbers and colonise habitats rapidly. Invasion success following different scales of disturbance was examined in the invasive acorn barnacle, Austrominiusmodestus, on a unique art installation located in Liverpool Bay. Population growth and recruitment success were examined by comparing recruitment rates within disturbance clearings of 4 different sizes and by contrasting population development with early recruitment rates over a 10 week period. Disturbed areas were rapidly recolonised and monocultures of A. modestus formed within 6 weeks. The size of patch created during disturbance had no effect on the rate of recruitment, while a linear relationship between recruit density and patch size was observed. Density-dependent processes mediated initial high recruitment resulting in population stability after 8-10 weeks, but densities continued to greatly exceed those reported in natural habitats. Given that artificial structures are likely to continue to proliferate in light of climate change projections, free-space is likely to become more available more frequently in the future supporting the expansion of fast-colonising species.

  5. Predicting free-space occupancy on novel artificial structures by an invasive intertidal barnacle using a removal experiment.

    Science.gov (United States)

    Bracewell, Sally A; Robinson, Leonie A; Firth, Louise B; Knights, Antony M

    2013-01-01

    Artificial structures can create novel habitat in the marine environment that has been associated with the spread of invasive species. They are often located in areas of high disturbance and can vary significantly in the area of free space provided for settlement of marine organisms. Whilst correlation between the amount of free space available and recruitment success has been shown in populations of several marine benthic organisms, there has been relatively little focus on invasive species, a group with the potential to reproduce in vast numbers and colonise habitats rapidly. Invasion success following different scales of disturbance was examined in the invasive acorn barnacle, Austrominiusmodestus, on a unique art installation located in Liverpool Bay. Population growth and recruitment success were examined by comparing recruitment rates within disturbance clearings of 4 different sizes and by contrasting population development with early recruitment rates over a 10 week period. Disturbed areas were rapidly recolonised and monocultures of A. modestus formed within 6 weeks. The size of patch created during disturbance had no effect on the rate of recruitment, while a linear relationship between recruit density and patch size was observed. Density-dependent processes mediated initial high recruitment resulting in population stability after 8-10 weeks, but densities continued to greatly exceed those reported in natural habitats. Given that artificial structures are likely to continue to proliferate in light of climate change projections, free-space is likely to become more available more frequently in the future supporting the expansion of fast-colonising species.

  6. Stable isotopic analysis of Barnacle larvae and their faecal pellets to evaluate the ingested food

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Anil, A.C.

    Stable isotopes of carbon and nitrogen are useful in the evaluation of food web dynamics and have been used extensively in the feeding studies. Barnacles are dominant component of the intertidal and bio-fouling communities. Life cycle of barnacles...

  7. 'Flying barnacles'

    DEFF Research Database (Denmark)

    Tøttrup, Anders P; Chan, Benny K K; Koskinen, Hannu

    2010-01-01

    in temperate areas spreading widely over inland and marine habitats outside the breeding season. The species is known to perform long-distance migration to Africa and the Middle East. Combining present knowledge on the birds' migratory pattern and the home range of the barnacle species, it is concluded...... that the cypris larvae of F. pallidus must have settled in African waters, whereas the area where F. albicostatus settled on the bird leg rings is less certain. The barnacles were of adult size and must thus have been attached for a period of no less than 2 months. More than 30 individual barnacles could occur...

  8. Differential recolonization of Atlantic intertidal habitats after disturbance reveals potential bottom-up community regulation.

    Science.gov (United States)

    Petzold, Willy; Scrosati, Ricardo A

    2014-01-01

    In the spring of 2014, abundant sea ice that drifted out of the Gulf of St. Lawrence caused extensive disturbance in rocky intertidal habitats on the northern Atlantic coast of mainland Nova Scotia, Canada. To monitor recovery of intertidal communities, we surveyed two wave-exposed locations in the early summer of 2014. Barnacle recruitment and the abundance of predatory dogwhelks were low at one location (Tor Bay Provincial Park) but more than 20 times higher at the other location (Whitehead). Satellite data indicated that the abundance of coastal phytoplankton (the main food source for barnacle larvae) was consistently higher at Whitehead just before the barnacle recruitment season, when barnacle larvae were in the water column. These observations suggest bottom-up forcing of intertidal communities. The underlying mechanisms and their intensity along the NW Atlantic coast could be investigated through studies done at local and regional scales.

  9. Growth rate variation of the stalked barnacle Pollicipes pollicipes (Crustacea: Cirripedia using calcein as a chemical marker

    Directory of Open Access Journals (Sweden)

    David Jacinto

    2015-03-01

    Full Text Available This study describes the use of calcein as a chemical tagging methodology to estimate growth rate variation of the stalked barnacle Pollicipes pollicipes, an ecologically important intertidal species and economic resource, in SW Portugal. Calcein tagging had a high success rate (94% in marking both juvenile and adult barnacles for a period of 2.5 months, providing a valuable method for obtaining reliable data in growth studies of P. pollicipes. Growth rate decreased with barnacle size and was highly variable amongst individuals, particularly in smaller barnacles. No effect of shore level on barnacle growth was detected. Growth rates were higher in smaller juvenile barnacles, peaking at a 1.1-mm monthly increment in rostro-carinal length (RC for individuals with RC=5 mm, and decreased with barnacle size (monthly growth rates of 0.5 mm for adult barnacles with RC~12.5 mm. Growth rates observed in adults with commercial interest (RC ≥ 18 mm was < 0.25 mm per month. The advantages of tagging P. pollicipes with calcein were the possibility of mass marking individual barnacles of different size cohorts within a short period (less than 1 day of manipulation; and reduced time of fieldwork, which is very important because this species inhabits very exposed rocky shores.

  10. Larval vision contributes to gregarious settlement in barnacles: adult red fluorescence as a possible visual signal

    KAUST Repository

    Matsumura, K.

    2014-02-26

    Gregarious settlement, an essential behavior for many barnacle species that can only reproduce by mating with a nearby barnacle, has long been thought to rely on larval ability to recognize chemical signals from conspecifics during settlement. However, the cyprid, the settlement stage larva in barnacles, has one pair of compound eyes that appear only at the late nauplius VI and cyprid stages, but the function(s) of these eyes remains unknown. Here we show that cyprids of the intertidal barnacle Balanus (=Amphibalanus) amphitrite can locate adult barnacles even in the absence of chemical cues, and prefer to settle around them probably via larval sense of vision. We also show that the cyprids can discriminate color and preferred to settle on red surfaces. Moreover, we found that shells of adult B. amphitrite emit red auto-fluorescence and the adult extracts with the fluorescence as a visual signal attracted cyprid larvae to settle around it. We propose that the perception of specific visual signals can be involved in behavior of zooplankton including marine invertebrate larvae, and that barnacle auto-fluorescence may be a specific signal involved in gregarious larval settlement.

  11. The relative magnitude of the effects of biological and physical settlement cues for cypris larvae of the acorn barnacle, Semibalanus balanoides L.

    NARCIS (Netherlands)

    Prendergast, G.S.; Zurn, C.M.; Bers, A.V.; Head, R.M.; Hansson, L.J.; Thomason, J.C.

    2009-01-01

    Barnacle cypris larvae respond to many cues when selecting a settlement site. The settlement of over a million larvae on tiles of different textures, orientations and densities of incumbent settlers was measured on the rocky intertidal at Great Cumbrae, Scotland. Half of the tiles were replaced

  12. Quantitative proteomics study of larval settlement in the barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan; Zhang, Huoming; Wang, Hao; Matsumura, Kiyotaka; Wong, Yue Him; Ravasi, Timothy; Qian, Pei-Yuan

    2014-01-01

    Barnacles are major sessile components of the intertidal areas worldwide, and also one of the most dominant fouling organisms in fouling communities. Larval settlement has a crucial ecological effect not only on the distribution of the barnacle population but also intertidal community structures. However, the molecular mechanisms involved in the transition process from the larval to the juvenile stage remain largely unclear. In this study, we carried out comparative proteomic profiles of stage II nauplii, stage VI nauplii, cyprids, and juveniles of the barnacle Balanus amphitrite using label-free quantitative proteomics, followed by the measurement of the gene expression levels of candidate proteins. More than 700 proteins were identified at each stage; 80 were significantly up-regulated in cyprids and 95 in juveniles vs other stages. Specifically, proteins involved in energy and metabolism, the nervous system and signal transduction were significantly up-regulated in cyprids, whereas proteins involved in cytoskeletal remodeling, transcription and translation, cell proliferation and differentiation, and biomineralization were up-regulated in juveniles, consistent with changes associated with larval metamorphosis and tissue remodeling in juveniles. These findings provided molecular evidence for the morphological, physiological and biological changes that occur during the transition process from the larval to the juvenile stages in B. amphitrite. © 2014 Chen et al.

  13. Quantitative proteomics study of larval settlement in the barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2014-02-13

    Barnacles are major sessile components of the intertidal areas worldwide, and also one of the most dominant fouling organisms in fouling communities. Larval settlement has a crucial ecological effect not only on the distribution of the barnacle population but also intertidal community structures. However, the molecular mechanisms involved in the transition process from the larval to the juvenile stage remain largely unclear. In this study, we carried out comparative proteomic profiles of stage II nauplii, stage VI nauplii, cyprids, and juveniles of the barnacle Balanus amphitrite using label-free quantitative proteomics, followed by the measurement of the gene expression levels of candidate proteins. More than 700 proteins were identified at each stage; 80 were significantly up-regulated in cyprids and 95 in juveniles vs other stages. Specifically, proteins involved in energy and metabolism, the nervous system and signal transduction were significantly up-regulated in cyprids, whereas proteins involved in cytoskeletal remodeling, transcription and translation, cell proliferation and differentiation, and biomineralization were up-regulated in juveniles, consistent with changes associated with larval metamorphosis and tissue remodeling in juveniles. These findings provided molecular evidence for the morphological, physiological and biological changes that occur during the transition process from the larval to the juvenile stages in B. amphitrite. © 2014 Chen et al.

  14. Transcriptomic analysis of neuropeptides and peptide hormones in the barnacle Balanus amphitrite: evidence of roles in larval settlement.

    KAUST Repository

    Yan, Xing-Cheng

    2012-10-02

    The barnacle Balanus amphitrite is a globally distributed marine crustacean and has been used as a model species for intertidal ecology and biofouling studies. Its life cycle consists of seven planktonic larval stages followed by a sessile juvenile/adult stage. The transitional processes between larval stages and juveniles are crucial for barnacle development and recruitment. Although some studies have been conducted on the neuroanatomy and neuroactive substances of the barnacle, a comprehensive understanding of neuropeptides and peptide hormones remains lacking. To better characterize barnacle neuropeptidome and its potential roles in larval settlement, an in silico identification of putative transcripts encoding neuropeptides/peptide hormones was performed, based on transcriptome of the barnacle B. amphitrite that has been recently sequenced. Potential cleavage sites andstructure of mature peptides were predicted through homology search of known arthropod peptides. In total, 16 neuropeptide families/subfamilies were predicted from the barnacle transcriptome, and 14 of them were confirmed as genuine neuropeptides by Rapid Amplification of cDNA Ends. Analysis of peptide precursor structures and mature sequences showed that some neuropeptides of B. amphitrite are novel isoforms and shared similar characteristics with their homologs from insects. The expression profiling of predicted neuropeptide genes revealed that pigment dispersing hormone, SIFamide, calcitonin, and B-type allatostatin had the highest expression level in cypris stage, while tachykinin-related peptide was down regulated in both cyprids and juveniles. Furthermore, an inhibitor of proprotein convertase related to peptide maturation effectively delayed larval metamorphosis. Combination of real-time PCR results and bioassay indicated that certain neuropeptides may play an important role in cypris settlement. Overall, new insight into neuropeptides/peptide hormones characterized in this study shall

  15. Transcriptomic analysis of neuropeptides and peptide hormones in the barnacle Balanus amphitrite: evidence of roles in larval settlement.

    KAUST Repository

    Yan, Xing-Cheng; Chen, Zhang-Fan; Sun, Jin; Matsumura, Kiyotaka; Wu, Rudolf S S; Qian, Pei-Yuan

    2012-01-01

    The barnacle Balanus amphitrite is a globally distributed marine crustacean and has been used as a model species for intertidal ecology and biofouling studies. Its life cycle consists of seven planktonic larval stages followed by a sessile juvenile/adult stage. The transitional processes between larval stages and juveniles are crucial for barnacle development and recruitment. Although some studies have been conducted on the neuroanatomy and neuroactive substances of the barnacle, a comprehensive understanding of neuropeptides and peptide hormones remains lacking. To better characterize barnacle neuropeptidome and its potential roles in larval settlement, an in silico identification of putative transcripts encoding neuropeptides/peptide hormones was performed, based on transcriptome of the barnacle B. amphitrite that has been recently sequenced. Potential cleavage sites andstructure of mature peptides were predicted through homology search of known arthropod peptides. In total, 16 neuropeptide families/subfamilies were predicted from the barnacle transcriptome, and 14 of them were confirmed as genuine neuropeptides by Rapid Amplification of cDNA Ends. Analysis of peptide precursor structures and mature sequences showed that some neuropeptides of B. amphitrite are novel isoforms and shared similar characteristics with their homologs from insects. The expression profiling of predicted neuropeptide genes revealed that pigment dispersing hormone, SIFamide, calcitonin, and B-type allatostatin had the highest expression level in cypris stage, while tachykinin-related peptide was down regulated in both cyprids and juveniles. Furthermore, an inhibitor of proprotein convertase related to peptide maturation effectively delayed larval metamorphosis. Combination of real-time PCR results and bioassay indicated that certain neuropeptides may play an important role in cypris settlement. Overall, new insight into neuropeptides/peptide hormones characterized in this study shall

  16. Transcriptomic Analysis of Neuropeptides and Peptide Hormones in the Barnacle Balanus amphitrite: Evidence of Roles in Larval Settlement

    Science.gov (United States)

    Yan, Xing-Cheng; Chen, Zhang-Fan; Sun, Jin; Matsumura, Kiyotaka; Wu, Rudolf S. S.; Qian, Pei-Yuan

    2012-01-01

    The barnacle Balanus amphitrite is a globally distributed marine crustacean and has been used as a model species for intertidal ecology and biofouling studies. Its life cycle consists of seven planktonic larval stages followed by a sessile juvenile/adult stage. The transitional processes between larval stages and juveniles are crucial for barnacle development and recruitment. Although some studies have been conducted on the neuroanatomy and neuroactive substances of the barnacle, a comprehensive understanding of neuropeptides and peptide hormones remains lacking. To better characterize barnacle neuropeptidome and its potential roles in larval settlement, an in silico identification of putative transcripts encoding neuropeptides/peptide hormones was performed, based on transcriptome of the barnacle B. amphitrite that has been recently sequenced. Potential cleavage sites andstructure of mature peptides were predicted through homology search of known arthropod peptides. In total, 16 neuropeptide families/subfamilies were predicted from the barnacle transcriptome, and 14 of them were confirmed as genuine neuropeptides by Rapid Amplification of cDNA Ends. Analysis of peptide precursor structures and mature sequences showed that some neuropeptides of B. amphitrite are novel isoforms and shared similar characteristics with their homologs from insects. The expression profiling of predicted neuropeptide genes revealed that pigment dispersing hormone, SIFamide, calcitonin, and B-type allatostatin had the highest expression level in cypris stage, while tachykinin-related peptide was down regulated in both cyprids and juveniles. Furthermore, an inhibitor of proprotein convertase related to peptide maturation effectively delayed larval metamorphosis. Combination of real-time PCR results and bioassay indicated that certain neuropeptides may play an important role in cypris settlement. Overall, new insight into neuropeptides/peptide hormones characterized in this study shall

  17. Transcriptomic analysis of neuropeptides and peptide hormones in the barnacle Balanus amphitrite: evidence of roles in larval settlement.

    Directory of Open Access Journals (Sweden)

    Xing-Cheng Yan

    Full Text Available The barnacle Balanus amphitrite is a globally distributed marine crustacean and has been used as a model species for intertidal ecology and biofouling studies. Its life cycle consists of seven planktonic larval stages followed by a sessile juvenile/adult stage. The transitional processes between larval stages and juveniles are crucial for barnacle development and recruitment. Although some studies have been conducted on the neuroanatomy and neuroactive substances of the barnacle, a comprehensive understanding of neuropeptides and peptide hormones remains lacking. To better characterize barnacle neuropeptidome and its potential roles in larval settlement, an in silico identification of putative transcripts encoding neuropeptides/peptide hormones was performed, based on transcriptome of the barnacle B. amphitrite that has been recently sequenced. Potential cleavage sites andstructure of mature peptides were predicted through homology search of known arthropod peptides. In total, 16 neuropeptide families/subfamilies were predicted from the barnacle transcriptome, and 14 of them were confirmed as genuine neuropeptides by Rapid Amplification of cDNA Ends. Analysis of peptide precursor structures and mature sequences showed that some neuropeptides of B. amphitrite are novel isoforms and shared similar characteristics with their homologs from insects. The expression profiling of predicted neuropeptide genes revealed that pigment dispersing hormone, SIFamide, calcitonin, and B-type allatostatin had the highest expression level in cypris stage, while tachykinin-related peptide was down regulated in both cyprids and juveniles. Furthermore, an inhibitor of proprotein convertase related to peptide maturation effectively delayed larval metamorphosis. Combination of real-time PCR results and bioassay indicated that certain neuropeptides may play an important role in cypris settlement. Overall, new insight into neuropeptides/peptide hormones characterized in

  18. STALKED BARNACLES CONCHODERMA AURITUM ON AN ...

    African Journals Online (AJOL)

    lower jaw, the palate and the penis of the sperm whale - Carke 1966). The occurrence of. C. auritum on the body skin of an elephant seal is therefore ... It can be inferred from Sorensen's remark that "barnacles up to an inch in length have been seen ... " that a stalked barnacle was involved, and Laws indeed refers to those.

  19. Development of monitoring protocols to detect change in rocky intertidal communities of Glacier Bay National Park and Preserve

    Science.gov (United States)

    Irvine, Gail V.

    2010-01-01

    Glacier Bay National Park and Preserve in southeastern Alaska includes extensive coastlines representing a major proportion of all coastlines held by the National Park Service. The marine plants and invertebrates that occupy intertidal shores form highly productive communities that are ecologically important to a number of vertebrate and invertebrate consumers and that are vulnerable to human disturbances. To better understand these communities and their sensitivity, it is important to obtain information on species abundances over space and time. During field studies from 1997 to 2001, I investigated probability-based rocky intertidal monitoring designs that allow inference of results to similar habitat within the bay and that reduce bias. Aerial surveys of a subset of intertidal habitat indicated that the original target habitat of bedrock-dominated sites with slope less than or equal to 30 degrees was rare. This finding illustrated the value of probability-based surveys and led to a shift in the target habitat type to more mixed rocky habitat with steeper slopes. Subsequently, I investigated different sampling methods and strategies for their relative power to detect changes in the abundances of the predominant sessile intertidal taxa: barnacles -Balanomorpha, the mussel Mytilus trossulus and the rockweed Fucus distichus subsp. evanescens. I found that lower-intensity sampling of 25 randomly selected sites (= coarse-grained sampling) provided a greater ability to detect changes in the abundances of these taxa than did more intensive sampling of 6 sites (= fine-grained sampling). Because of its greater power, the coarse-grained sampling scheme was adopted in subsequent years. This report provides detailed analyses of the 4 years of data and evaluates the relative effect of different sampling attributes and management-set parameters on the ability of the sampling to detect changes in the abundances of these taxa. The intent was to provide managers with information

  20. Short communications Goose barnacles on seals and a penguin at ...

    African Journals Online (AJOL)

    Short communications Goose barnacles on seals and a penguin at Gough Island. ... to the pelage of two of the 12 elephant seals (Mirounga leonina) inspected and one ... We also recorded a goose barnacle attached to a Northern rockhopper ...

  1. The tempo and mode of barnacle evolution

    DEFF Research Database (Denmark)

    Pérez-Losada, Marcos; Harp, Margaret; Høeg, Jens T

    2008-01-01

    (outgroup) species representing almost all the Thoracica families to assess the tempo and mode of barnacle evolution. Using phylogenetic methods of maximum parsimony, maximum likelihood, and Bayesian inference and 14 fossil calibrations, we found that: (1) Iblomorpha form a monophyletic group; (2......) pedunculated barnacles without shell plates (Heteralepadomorpha) are not ancestral, but have evolved, at least twice, from plated forms; (3) the ontogenetic pattern with 5-->6-->8-->12+ plates does not reflect Thoracica shell evolution; (4) the traditional asymmetric barnacles (Verrucidae) and the Balanomorpha......) the Thoracica suborders evolved since the Early Carboniferous (340mya) with the final radiation of the Sessilia in the Upper Jurassic (147mya). These results, therefore, reject many of the underlying hypotheses about character evolution in the Cirripedia Thoracica, stimulate a variety of new thoughts...

  2. Grazing effects of the periwinkle Echinolittorina peruviana at a central Peruvian high rocky intertidal

    Science.gov (United States)

    Hidalgo, Fernando J.; Firstater, Fausto N.; Fanjul, Eugenia; Bazterrica, M. Cielo; Lomovasky, Betina J.; Tarazona, Juan; Iribarne, Oscar O.

    2008-03-01

    Echinolittorina peruviana is the most common gastropod in the high intertidal zone of Peru, representing more than 80% of the individuals present at that zone. Experimental removal of snails was used to evaluate their effects on (a) abundance of epilithic biofilm, (b) barnacle recruitment, and (c) abundance of macroalgae under “normal” conditions of the El Niño Southern Oscillation (ENSO). Experiments were carried out from October 2005 to April 2007 at two intertidal levels of a semi-protected rocky shore of central Peru. Results demonstrated that E. peruviana is able to control biofilm abundance and barnacle recruitment at both heights investigated, with marked effects in the lower zone. Erect macroalgae ( Ulva spp. and Gelidium spp.) were less affected by grazing; but negative effects were observed on macroalgal crusts. Season and physical stress seem to play a more important role in the abundance of macroalgae in the high intertidal. Our results are similar to those reported elsewhere for high shore littorinids and represent baseline data to understand how the role of intertidal consumers will vary under the cold (La Niña) and warm (El Niño) phases of ENSO on these shores.

  3. Non-linear density-dependent effects of an intertidal ecosystem engineer.

    Science.gov (United States)

    Harley, Christopher D G; O'Riley, Jaclyn L

    2011-06-01

    Ecosystem engineering is an important process in a variety of ecosystems. However, the relationship between engineer density and engineering impact remains poorly understood. We used experiments and a mathematical model to examine the role of engineer density in a rocky intertidal community in northern California. In this system, the whelk Nucella ostrina preys on barnacles (Balanus glandula and Chthamalus dalli), leaving empty barnacle tests as a resource (favorable microhabitat) for other species. Field experiments demonstrated that N. ostrina predation increased the availability of empty tests of both barnacle species, reduced the density of the competitively dominant B. glandula, and indirectly increased the density of the competitively inferior C. dalli. Empty barnacle tests altered microhabitat humidity, but not temperature, and presumably provided a refuge from wave action. The herbivorous snail Littorina plena was positively associated with empty test availability in both observational comparisons and experimental manipulations of empty test availability, and L. plena density was elevated in areas with foraging N. ostrina. To explore the effects of variation in N. ostrina predation, we constructed a demographic matrix model for barnacles in which we varied predation intensity. The model predicted that number of available empty tests increases with predation intensity to a point, but declines when predation pressure was strong enough to severely reduce adult barnacle densities. The modeled number of available empty tests therefore peaked at an intermediate level of N. ostrina predation. Non-linear relationships between engineer density and engineer impact may be a generally important attribute of systems in which engineers influence the population dynamics of the species that they manipulate.

  4. Large-scale gene flow in the barnacle Jehlius cirratus and contrasts with other broadly-distributed taxa along the Chilean coast

    Directory of Open Access Journals (Sweden)

    Baoying Guo

    2017-02-01

    Full Text Available We evaluate the population genetic structure of the intertidal barnacle Jehlius cirratus across a broad portion of its geographic distribution using data from the mitochondrial cytochrome oxidase I (COI gene region. Despite sampling diversity from over 3,000 km of the linear range of this species, there is only slight regional structure indicated, with overall Φ CT of 0.036 (p < 0.001 yet no support for isolation by distance. While these results suggest greater structure than previous studies of J. cirratus had indicated, the pattern of diversity is still far more subtle than in other similarly-distributed species with similar larval and life history traits. We compare these data and results with recent findings in four other intertidal species that have planktotrophic larvae. There are no clear patterns among these taxa that can be associated with intertidal depth or other known life history traits.

  5. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan; Wang, Hao; Matsumura, Kiyotaka; Qian, Pei-Yuan

    2012-01-01

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  6. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2012-02-13

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  7. Adaptive evolution of sexual systems in pedunculate barnacles

    DEFF Research Database (Denmark)

    Yusa, Yoichi; Yoshikawa, Mai; Kitaura, Jun

    2012-01-01

    (androdioecy), and coexistence of dwarf males and females (dioecy). Here, we report the first phylogenetically controlled test of the hypothesis that the ultimate cause of the diverse sexual systems and presence of dwarf males in this group is limited mating opportunities for non-dwarf individuals, owing...... to mating in small groups. Within the pedunculate barnacle phylogeny, dwarf males and females have evolved repeatedly. Females are more likely to evolve in androdioecious than hermaphroditic populations, suggesting that evolution of dwarf males has preceded that of females in pedunculates. Both dwarf males...... and females are associated with a higher proportion of solitary individuals in the population, corroborating the hypothesis that limited mating opportunities have favoured evolution of these diverse sexual systems, which have puzzled biologists since Darwin....

  8. Effect of barnacle fouling on ship resistance and powering.

    Science.gov (United States)

    Demirel, Yigit Kemal; Uzun, Dogancan; Zhang, Yansheng; Fang, Ho-Chun; Day, Alexander H; Turan, Osman

    2017-11-01

    Predictions of added resistance and the effective power of ships were made for varying barnacle fouling conditions. A series of towing tests was carried out using flat plates covered with artificial barnacles. The tests were designed to allow the examination of the effects of barnacle height and percentage coverage on the resistance and effective power of ships. The drag coefficients and roughness function values were evaluated for the flat plates. The roughness effects of the fouling conditions on the ships' frictional resistances were predicted. Added resistance diagrams were then plotted using these predictions, and powering penalties for these ships were calculated using the diagrams generated. The results indicate that the effect of barnacle size is significant, since a 10% coverage of barnacles each 5 mm in height caused a similar level of added power requirements to a 50% coverage of barnacles each 1.25 mm in height.

  9. Proportionality lost - proportionality regained?

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2010-01-01

    In recent years, the European Court of Justice (the ECJ) seems to have accepted restrictions on the freedom of establishment and other basic freedoms, despite the fact that a more thorough proportionality test would have revealed that the restriction in question did not pass the 'rule of reason' ...

  10. Elemental microchemistry, fatty acid profile and geometric morphometrics signatures of goose barnacles (Pollicipes pollicipes reveal their place of origin

    Directory of Open Access Journals (Sweden)

    Rui Albuquerque

    2014-06-01

    Full Text Available Seafood plays an important role in the socioeconomic, gastronomy and cultural heritage of Portuguese coastal communities. In the Iberian Peninsula, the goose barnacle Pollicipes pollicipes is the intertidal biological resource most heavily exploited by man, resulting on overexploitation of stocks. In the MPA of BNR P.pollicipes harvesting is however strictly regulated, making it a good example of marine resources management. Analytical methods able to identify the origin of goose barnacle would be an important tool to help the management of the trade. For such purpose, we investigated whether P. pollicipes have site-specific differences based on its elemental microchemistry (EM, fatty acid profile (FA and capitulum shape (CS. The analysis was performed on specimens collected from 3 sites in the BNR and 7 along a 300 km stretch of the Portuguese coast. For each individual we analysed the largest lateral shell for EM using ICP-MS, the FA content of the muscle using GC-FID, and the CS using geometric morphometrics. Discriminant function analyses (DFA for both EM and FA separately provided a high reclassification success (77.6% and 99% respectively, of cross-validated cases correctly classified, while for EM combined with FA allowed for a 100% reclassification success. DFA analysis based only on CS, revealed a low classification success (29.6%. These results show that EM and FA signatures can be a powerful tool to infer goose barnacles origin. Such “fingerprinting” approach can be used to track and identify goose barnacles origin, helping in establishing an origin certificate and increasing the potential value of biological resources from Portuguese MPAs.

  11. The November 2011 irruption of buoy barnacles Dosima fascicularis ...

    African Journals Online (AJOL)

    Buoy barnacles not uncommonly strand in the region attached to feathers, plastic litter and other small objects, but the 2011 irruption saw exceptional numbers of unusually large colonies (average 23.5 individuals; SD 18.5), most of ... Buoy barnacles were first observed at sea off the Cape Peninsula on 2 November 2011.

  12. Phylogeny and evolution of life history strategies of the Parasitic Barnacles (Crustacea, Cirripedia, Rhizocephala)

    DEFF Research Database (Denmark)

    Glenner, Henrik; Hebsgaard, Martin Bay

    2006-01-01

    The barnacles (Crustacea, Cirripedia) consist of three well-defined orders: the conventional filter-feeding barnacles (Thoracica), the burrowing barnacles (Acrothoracica), and the parasitic barnacles (Rhizocephala). Thoracica and Acrothoracica feed by catching food particles from the surrounding ...... crustaceans (Anomura), which includes hermit crabs and squat lobsters....

  13. Ecology and Evolution of Phenotypic Plasticity in the Penis and Cirri of Barnacles.

    Science.gov (United States)

    Hoch, J Matthew; Schneck, Daniel T; Neufeld, Christopher J

    2016-10-01

    Most barnacles are sessile, simultaneous hermaphrodites that reproduce by copulation. This is achieved through the extension of a muscular penis, famous for being the proportionally largest in the animal kingdom. The penis is a long cylindrical or conical organ, composed of a series of folded rings, allowing it to stretch to great lengths. The penises are covered with chemosensory setae allowing them to seek out receptive neighbors. For many species, the condition of the penis changes seasonally. In the most extreme circumstances, it degenerates and is shed during the first post-mating molt and is re-grown for the next mating season. Barnacle penises have been shown to exhibit phenotypic plasticity in response to many different challenges. When exposed to heavy waves, diameter is increased by thickening both the cuticle and muscles. When mates are far, length increases by adding ringed annulations. Experiments have shown that these plastic traits are modular, capable of changing independently from each other and that they improve mating ability. Alternate strategies to increase reproductive ability by barnacles include the production of dwarf and complemental males, sperm casting and sperm leakage, and aerial copulation. All of these mating strategies may have important implications for the study of reproductive biology, life history, and sex allocation theory. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  14. Sampling design for long-term regional trends in marine rocky intertidal communities

    Science.gov (United States)

    Irvine, Gail V.; Shelley, Alice

    2013-01-01

    Probability-based designs reduce bias and allow inference of results to the pool of sites from which they were chosen. We developed and tested probability-based designs for monitoring marine rocky intertidal assemblages at Glacier Bay National Park and Preserve (GLBA), Alaska. A multilevel design was used that varied in scale and inference. The levels included aerial surveys, extensive sampling of 25 sites, and more intensive sampling of 6 sites. Aerial surveys of a subset of intertidal habitat indicated that the original target habitat of bedrock-dominated sites with slope ≤30° was rare. This unexpected finding illustrated one value of probability-based surveys and led to a shift in the target habitat type to include steeper, more mixed rocky habitat. Subsequently, we evaluated the statistical power of different sampling methods and sampling strategies to detect changes in the abundances of the predominant sessile intertidal taxa: barnacles Balanomorpha, the mussel Mytilus trossulus, and the rockweed Fucus distichus subsp. evanescens. There was greatest power to detect trends in Mytilus and lesser power for barnacles and Fucus. Because of its greater power, the extensive, coarse-grained sampling scheme was adopted in subsequent years over the intensive, fine-grained scheme. The sampling attributes that had the largest effects on power included sampling of “vertical” line transects (vs. horizontal line transects or quadrats) and increasing the number of sites. We also evaluated the power of several management-set parameters. Given equal sampling effort, sampling more sites fewer times had greater power. The information gained through intertidal monitoring is likely to be useful in assessing changes due to climate, including ocean acidification; invasive species; trampling effects; and oil spills.

  15. Feeding by larvae of intertidal invertebrates: assessing their position in pelagic food webs.

    Science.gov (United States)

    Vargas, Cristian A; Manríquez, Patricio H; Navarrete, Sergio A

    2006-02-01

    One of the leading determinants of the structure and dynamics of marine populations is the rate of arrival of new individuals to local sites. While physical transport processes play major roles in delivering larvae to the shore, these processes become most important after larvae have survived the perils of life in the plankton, where they usually suffer great mortality. The lack of information regarding larval feeding makes it difficult to assess the effects of food supply on larval survival, or the role larvae may play in nearshore food webs. Here, we examine the spectrum of food sizes and food types consumed by the larvae of two intertidal barnacle species and of the predatory gastropod Concholepas concholepas. We conducted replicated experiments in which larvae were exposed to the food size spectrum (phytoplankton, microprotozoan and autotrophic picoplankton) found in nearshore waters in central Chile. Results show that barnacle nauplii and gastropod veligers are omnivorous grazers, incorporating significant fractions of heterotrophs in their diets. In accordance with their feeding mechanisms and body size, barnacle nauplii were able to feed on autotrophic picoplankton (concholepas larvae also consumed picoplankton cells, while competent larvae of this species ingested mostly the largest phytoplankton cells and heterotrophic protozoans. Results suggest that persistent changes in the structure of pelagic food webs can have important effects on the species-specific food availability for invertebrate larvae, which can result in large-scale differences in recruitment rates of a given species, and in the relative recruitment success of the different species that make up benthic communities.

  16. What do barnacle larvae feed on ? Implications in biofouling ecology

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.; Anil, A.C.

    in experimental studies. Larval development in this barnacle includes planktotrophic naupliar stages followed by pre-settling cyprid instar. Studies have shown that availability of food during naupliar development is of critical importance to successful...

  17. Climate Change and Intertidal Wetlands

    Directory of Open Access Journals (Sweden)

    Pauline M. Ross

    2013-03-01

    Full Text Available Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause—the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the “squeeze” experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

  18. Climate change and intertidal wetlands.

    Science.gov (United States)

    Ross, Pauline M; Adam, Paul

    2013-03-19

    Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause-the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the "squeeze" experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

  19. Proportional reasoning

    DEFF Research Database (Denmark)

    Dole, Shelley; Hilton, Annette; Hilton, Geoff

    2015-01-01

    Proportional reasoning is widely acknowledged as a key to success in school mathematics, yet students’ continual difficulties with proportion-related tasks are well documented. This paper draws on a large research study that aimed to support 4th to 9th grade teachers to design and implement tasks...

  20. Phylogeographic structure and northward range expansion in the barnacle Chthamalus fragilis

    Directory of Open Access Journals (Sweden)

    Annette F. Govindarajan

    2015-04-01

    Full Text Available The barnacle Chthamalus fragilis is found along the US Atlantic seaboard historically from the Chesapeake Bay southward, and in the Gulf of Mexico. It appeared in New England circa 1900 coincident with warming temperatures, and is now a conspicuous member of rocky intertidal communities extending through the northern shore of Cape Cod, Massachusetts. The origin of northern C. fragilis is debated. It may have spread to New England from the northern end of its historic range through larval transport by ocean currents, possibly mediated by the construction of piers, marinas, and other anthropogenic structures that provided new hard substrate habitat. Alternatively, it may have been introduced by fouling on ships originating farther south in its historic distribution. Here we examine mitochondrial cytochrome c oxidase I sequence diversity and the distribution of mitochondrial haplotypes of C. fragilis from 11 localities ranging from Cape Cod, to Tampa Bay, Florida. We found significant genetic structure between northern and southern populations. Phylogenetic analysis revealed three well-supported reciprocally monophyletic haplogroups, including one haplogroup that is restricted to New England and Virginia populations. While the distances between clades do not suggest cryptic speciation, selection and dispersal barriers may be driving the observed structure. Our data are consistent with an expansion of C. fragilis from the northern end of its mid-19th century range into Massachusetts.

  1. Transcriptome and proteome dynamics in larvae of the barnacle Balanus Amphitrite from the Red Sea

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2015-12-15

    Background The barnacle Balanus amphitrite is widely distributed in marine shallow and tidal waters, and has significant economic and ecological importance. Nauplii, the first larval stage of most crustaceans, are extremely abundant in the marine zooplankton. However, a lack of genome information has hindered elucidation of the molecular mechanisms of development, settlement and survival strategies in extreme marine environments. We sequenced and constructed the genome dataset for nauplii to obtain comprehensive larval genetic information. We also investigated iTRAQ-based protein expression patterns to reveal the molecular basis of nauplii development, and to gain information on larval survival strategies in the Red Sea marine environment. Results A nauplii larval transcript dataset, containing 92,117 predicted open reading frames (ORFs), was constructed and used as a reference for the proteome analysis. Genes related to translation, oxidative phosphorylation and cytoskeletal development were highly abundant. We observed remarkable plasticity in the proteome of Red Sea larvae. The proteins associated with development, stress responses and osmoregulation showed the most significant differences between the two larval populations studied. The synergistic overexpression of heat shock and osmoregulatory proteins may facilitate larval survival in intertidal habitats or in extreme environments. Conclusions We presented, for the first time, comprehensive transcriptome and proteome datasets for Red Sea nauplii. The datasets provide a foundation for future investigations focused on the survival mechanisms of other crustaceans in extreme marine environments.

  2. High spectral resolution image of Barnacle Bill

    Science.gov (United States)

    1997-01-01

    The rover Sojourner's first target for measurement by the Alpha-Proton-Xray Spectrometer (APXS) was the rock named Barnacle Bill, located close to the ramp down which the rover made its egress from the lander. The full spectral capability of the Imager for Mars Pathfinder (IMP), consisting of 13 wavelength filters, was used to characterize the rock's surface. The measured area is relatively dark, and is shown in blue. Nearby on the rock surface, soil material is trapped in pits (shown in red).Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  3. Morphometric and molecular identification of individual barnacle cyprids from wild plankton: an approach to detecting fouling and invasive barnacle species.

    Science.gov (United States)

    Chen, Hsi-Nien; Høeg, Jens T; Chan, Benny K K

    2013-01-01

    The present study used DNA barcodes to identify individual cyprids to species. This enables accurate quantification of larvae of potential fouling species in the plankton. In addition, it explains the settlement patterns of barnacles and serves as an early warning system of unwanted immigrant species. Sequences from a total of 540 individual cypris larvae from Taiwanese waters formed 36 monophyletic clades (species) in a phylogenetic tree. Of these clades, 26 were identified to species, but 10 unknown monophyletic clades represented non-native species. Cyprids of the invasive barnacle, Megabalanus cocopoma, were identified. Multivariate analysis of antennular morphometric characters revealed three significant clusters in a nMDS plot, viz. a bell-shaped attachment organ (most species), a shoe-shaped attachment organ (some species), and a spear-shaped attachment organ (coral barnacles only). These differences in attachment organ structure indicate that antennular structures interact directly with the diverse substrata involved in cirripede settlement.

  4. ADOPTION OF YOUNG AND INTRASPECIFIC NEST PARASITISM IN BARNACLE GEESE

    NARCIS (Netherlands)

    CHOUDHURY, S; JONES, CS; BLACK, JM; PROP, J

    Prior to use of genetic techniques, extra-pair copulations and intraspecific brood parasitism were rarely observed in long-term monogamous geese. DNA fingerprinting analysis of nine families of Barnacle Geese (Branta leucopsis) revealed one case of intraspecific nest parasitism with the offspring

  5. Additions to the barnacle (Crustacea: Cirripedia) fauna of South Africa

    African Journals Online (AJOL)

    The purpose of this paper is to document recent additions to the South African barnacle (Cirripedia) fauna. New species records were obtained by examining accumulated collections of unidentified material in the Iziko South African Museum, as well as via material collected directly by the authors. Fourteen species, none of ...

  6. Grazer diversity interacts with biogenic habitat heterogeneity to accelerate intertidal algal succession.

    Science.gov (United States)

    Whalen, Matthew A; Aquilino, Kristin M; Stachowicz, John J

    2016-08-01

    Environmental heterogeneity contributes to coexistence by allowing species with different traits to persist when different species perform best at different times or places. This interaction between niche differences and environmental variability may also help explain relationships between biodiversity and ecosystem functioning, but few data are available to rigorously evaluate this hypothesis. We assessed how a biologically relevant aspect of environmental heterogeneity interacts with species diversity to determine ecosystem processes in a natural rocky intertidal community. We used field removals to factorially manipulate biogenic habitat heterogeneity (barnacles, bare rock, and plots that were 50/50 mixes of the two habitat types) and gastropod grazer species richness and then tracked algal community succession and recovery over the course of 1 yr. We found that herbivore diversity, substrate heterogeneity, and their interaction played unique roles in the peak abundance and timing of occurrence of different algal functional groups. Early successional microalgae were most heavily grazed in diverse herbivore assemblages and those with barnacles present, which was likely due to complementary feeding strategies among all three grazers. In contrast, late successional macroalgae were strongly influenced by the presence of a habitat generalist limpet. In this herbivore's absence, heterogeneous habitats (i.e., mixtures of bare rock and barnacles) experienced the greatest algal accumulation, which was partly a result of complementary habitat use by the remaining herbivores. The complex way habitat identity and heterogeneity altered grazer-algal interactions in our study suggests species' differences and environmental heterogeneity both separately and interactively contribute to the relationship between biodiversity and ecosystem functions. © 2016 by the Ecological Society of America.

  7. Physiological community ecology: variation in metabolic activity of ecologically important rocky intertidal invertebrates along environmental gradients.

    Science.gov (United States)

    Dahlhoff, Elizabeth P; Stillman, Jonathon H; Menge, Bruce A

    2002-08-01

    Rocky intertidal invertebrates live in heterogeneous habitats characterized by steep gradients in wave activity, tidal flux, temperature, food quality and food availability. These environmental factors impact metabolic activity via changes in energy input and stress-induced alteration of energetic demands. For keystone species, small environmentally induced shifts in metabolic activity may lead to disproportionately large impacts on community structure via changes in growth or survival of these key species. Here we use biochemical indicators to assess how natural differences in wave exposure, temperature and food availability may affect metabolic activity of mussels, barnacles, whelks and sea stars living at rocky intertidal sites with different physical and oceanographic characteristics. We show that oxygen consumption rate is correlated with the activity of key metabolic enzymes (e.g., citrate synthase and malate dehydrogenase) for some intertidal species, and concentrations of these enzymes in certain tissues are lower for starved individuals than for those that are well fed. We also show that the ratio of RNA to DNA (an index of protein synthetic capacity) is highly variable in nature and correlates with short-term changes in food availability. We also observed striking patterns in enzyme activity and RNA/DNA in nature, which are related to differences in rocky intertidal community structure. Differences among species and habitats are most pronounced in summer and are linked to high nearshore productivity at sites favored by suspension feeders and to exposure to stressful low-tide air temperatures in areas of low wave splash. These studies illustrate the great promise of using biochemical indicators to test ecological models, which predict changes in community structure along environmental gradients. Our results also suggest that biochemical indices must be carefully validated with laboratory studies, so that the indicator selected is likely to respond to the

  8. The influence of Pleistocene climatic changes and ocean currents on the phylogeography of the southern African barnacle, Tetraclita serrata (Thoracica; Cirripedia.

    Directory of Open Access Journals (Sweden)

    Terry V Reynolds

    Full Text Available The evolutionary effects of glacial periods are poorly understood for Southern Hemisphere marine intertidal species, particularly obligatory sessile organisms. We examined this by assessing the phylogeographic patterns of the southern African volcano barnacle, Tetraclita serrata, a dominant species on rocky intertidal shores. Restricted gene flow in some geographical areas was hypothesized based on oceanic circulation patterns and known biogeographic regions. Barnacle population genetic structure was investigated using the mitochondrial cytochrome oxidase subunit 1 (COI region for 410 individuals sampled from 20 localities spanning the South African coast. The mtDNA data were augmented by generating nuclear internal transcribed spacer 1 (ITS1 sequences from a subset of samples. Phylogenetic and population genetic analyses of mitochondrial DNA data reveal two distinct clades with mostly sympatric distributions, whereas nuclear analyses reveal only a single lineage. Shallow, but significant structure (0.0041-0.0065, P<0.01 was detected for the mtDNA data set, with the south-west African region identified as harbouring the highest levels of genetic diversity. Gene flow analyses on the mtDNA data show that individuals sampled in south-western localities experience gene flow primarily in the direction of the Benguela Current, while south and eastern localities experience bi-directional gene flow, suggesting an influence of both the inshore currents and the offshore Agulhas Current in the larval distribution of T. serrata. The mtDNA haplotype network, Bayesian Skyline Plots, mismatch distributions and time since expansion indicate that T. serrata population numbers were not severely affected by the Last Glacial Maximum (LGM, unlike other southern African marine species. The processes resulting in the two morphologically cryptic mtDNA lineages may be the result of a recent historical allopatric event followed by secondary contact or could reflect

  9. A comparative study of the accumulation of metals in the barnacle (Tetraclita serrata and the black mussel (Choromytilis meridionalis in False Bay, South Africa

    Directory of Open Access Journals (Sweden)

    Adriaan J. Reinecke

    2014-02-01

    Full Text Available The development of methods to monitor the South African coastal waters offer major challenges. Knowledge and availability of suitable species that may serve as biomonitors will be valuable to obtain information to support good management decisions. It is therefore important to identify local species that show the basic characteristics required for biomonitoring. The aim of this study was to compare, as part of a wider seasonal field study of metals in the intertidal zone of False Bay, South Africa, the body loads of copper (Cu, nickel (Ni, lead (Pb, cadmium (Cd and zinc (Zn in the black mussel (C. meridionalis and the barnacle (T. serrata, and to compare these with environmental concentrations. Also to draw conclusions about the animals’ relative abilities to accumulate priority metals. Specimens of both species were collected over several seasons at different points in False Bay and analysed chemically. The mean body load (soft tissue and shell of metals was higher in the black mussel than in the barnacle during all seasons. A comparison between the body loads and environmental concentrations in water and sediment showed that the priority metals Cd, Ni and Pb are accumulated strongly by both C. meridionalis and T. serrata. The mean Cd body loads varied between 6.43 µg/g and 14.73 µg/g for the various seasons but was not statistically significantly different between seasons. Metal concentrations were in most cases highest during winter. Multiple regression analysis showed a strong correlation between body load of metals in the black mussel and the environmental concentration for most seasons, which indicates that the black mussel can be useful as an active rather than a passive biomonitor. The concept of biomonitoring has merit because it may show long-term tendencies, but it does not offer an absolute measure of immediate, varying pollution levels. It could serve as an additional management tool in a national marine programme for the

  10. Toward an understanding of the molecular mechanisms of barnacle larval settlement: A comparative transcriptomic approach

    KAUST Repository

    Chen, Zhang-Fan

    2011-07-29

    Background: The barnacle Balanus amphitrite is a globally distributed biofouler and a model species in intertidal ecology and larval settlement studies. However, a lack of genomic information has hindered the comprehensive elucidation of the molecular mechanisms coordinating its larval settlement. The pyrosequencing-based transcriptomic approach is thought to be useful to identify key molecular changes during larval settlement. Methodology and Principal Findings: Using 454 pyrosequencing, we collected totally 630,845 reads including 215,308 from the larval stages and 415,537 from the adults; 23,451 contigs were generated while 77,785 remained as singletons. We annotated 31,720 of the 92,322 predicted open reading frames, which matched hits in the NCBI NR database, and identified 7,954 putative genes that were differentially expressed between the larval and adult stages. Of these, several genes were further characterized with quantitative real-time PCR and in situ hybridization, revealing some key findings: 1) vitellogenin was uniquely expressed in late nauplius stage, suggesting it may be an energy source for the subsequent non-feeding cyprid stage; 2) the locations of mannose receptors suggested they may be involved in the sensory system of cyprids; 3) 20 kDa-cement protein homologues were expressed in the cyprid cement gland and probably function during attachment; and 4) receptor tyrosine kinases were expressed higher in cyprid stage and may be involved in signal perception during larval settlement. Conclusions: Our results provide not only the basis of several new hypotheses about gene functions during larval settlement, but also the availability of this large transcriptome dataset in B. amphitrite for further exploration of larval settlement and developmental pathways in this important marine species. © 2011 Chen et al.

  11. Barnacle Geese Achieve Significant Energetic Savings by Changing Posture

    OpenAIRE

    Tickle, Peter G.; Nudds, Robert L.; Codd, Jonathan R.

    2012-01-01

    Here we report the resting metabolic rate in barnacle geese (Branta leucopsis) and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy con...

  12. Long-term effects of Exxon Valdez oiling and shoreline treatments on rocky intertidal epibiota

    International Nuclear Information System (INIS)

    Houghton, J.P.; Fukuyama, A.K.; Lees, D.C.; Driskell, W.B.; Shigenaka, G.; Mearns, A.J.

    1993-01-01

    Hot-water treatments used to remove Exxon Valdez oil from rocky beaches of Prince William Sound in 1989 were shown to have severe short-term impacts on intertidal epibenthos. Quantitative sampling was conducted from 1989 through 1993 to evaluate recovery of littoral habitats from the effects of oiling and hotwater washing. Effects of hot-water treatments applied in 1989 remained visible in intertidal assemblages through 1993. Some hot-water treated rocky shores that had been stripped of biota showed little colonization by 1991; significant differences remained between epibiota on unoiled shores and that on oiled shores that were hot-water washed. On other oiled rocky shores that were not hot-water washed, the majority of the community dominants, including rockweed, mussels, barnacles, limpets, drills, and littorines, survived the oiling; by July 1991 these shores did not differ in most respects from unoiled shores. By July 1993 hot-water-washed rocky shores had been colonized by opportunistic species as well as by most of the original biota. Algal assemblages were heavily dominated by rockweed, but red algae reminded depressed, especially at lower elevations; otherwise, few significant differences remained in 1993 between the epibiota on unoiled and hot-water-washed shores. Full recovery appears to be several years away in many areas, however

  13. Supplementary Material for: Transcriptome and proteome dynamics in larvae of the barnacle Balanus Amphitrite from the Red Sea

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Al-Aqeel, Sarah; Ryu, Tae Woo; Zhang, Huoming; Seridi, Loqmane; Ghosheh, Yanal; Qian, Pei-Yuan; Ravasi, Timothy

    2015-01-01

    Abstract Background The barnacle Balanus amphitrite is widely distributed in marine shallow and tidal waters, and has significant economic and ecological importance. Nauplii, the first larval stage of most crustaceans, are extremely abundant in the marine zooplankton. However, a lack of genome information has hindered elucidation of the molecular mechanisms of development, settlement and survival strategies in extreme marine environments. We sequenced and constructed the genome dataset for nauplii to obtain comprehensive larval genetic information. We also investigated iTRAQ-based protein expression patterns to reveal the molecular basis of nauplii development, and to gain information on larval survival strategies in the Red Sea marine environment. Results A nauplii larval transcript dataset, containing 92,117 predicted open reading frames (ORFs), was constructed and used as a reference for the proteome analysis. Genes related to translation, oxidative phosphorylation and cytoskeletal development were highly abundant. We observed remarkable plasticity in the proteome of Red Sea larvae. The proteins associated with development, stress responses and osmoregulation showed the most significant differences between the two larval populations studied. The synergistic overexpression of heat shock and osmoregulatory proteins may facilitate larval survival in intertidal habitats or in extreme environments. Conclusions We presented, for the first time, comprehensive transcriptome and proteome datasets for Red Sea nauplii. The datasets provide a foundation for future investigations focused on the survival mechanisms of other crustaceans in extreme marine environments.

  14. Adhesive proteins of stalked and acorn barnacles display homology with low sequence similarities.

    Directory of Open Access Journals (Sweden)

    Jaimie-Leigh Jonker

    Full Text Available Barnacle adhesion underwater is an important phenomenon to understand for the prevention of biofouling and potential biotechnological innovations, yet so far, identifying what makes barnacle glue proteins 'sticky' has proved elusive. Examination of a broad range of species within the barnacles may be instructive to identify conserved adhesive domains. We add to extensive information from the acorn barnacles (order Sessilia by providing the first protein analysis of a stalked barnacle adhesive, Lepas anatifera (order Lepadiformes. It was possible to separate the L. anatifera adhesive into at least 10 protein bands using SDS-PAGE. Intense bands were present at approximately 30, 70, 90 and 110 kilodaltons (kDa. Mass spectrometry for protein identification was followed by de novo sequencing which detected 52 peptides of 7-16 amino acids in length. None of the peptides matched published or unpublished transcriptome sequences, but some amino acid sequence similarity was apparent between L. anatifera and closely-related Dosima fascicularis. Antibodies against two acorn barnacle proteins (ab-cp-52k and ab-cp-68k showed cross-reactivity in the adhesive glands of L. anatifera. We also analysed the similarity of adhesive proteins across several barnacle taxa, including Pollicipes pollicipes (a stalked barnacle in the order Scalpelliformes. Sequence alignment of published expressed sequence tags clearly indicated that P. pollicipes possesses homologues for the 19 kDa and 100 kDa proteins in acorn barnacles. Homology aside, sequence similarity in amino acid and gene sequences tended to decline as taxonomic distance increased, with minimum similarities of 18-26%, depending on the gene. The results indicate that some adhesive proteins (e.g. 100 kDa are more conserved within barnacles than others (20 kDa.

  15. Introduction to the symposium--barnacle biology: essential aspects and contemporary approaches.

    Science.gov (United States)

    Zardus, John D

    2012-09-01

    Barnacles have evolved a number of specialized features peculiar for crustaceans: they produce a calcified, external shell; they exhibit sexual strategies involving dioecy and androdioecy; and some have become internal parasites of other Crustacea. The thoroughly sessile habit of adults also belies the highly mobile and complex nature of their larval stages. Given these and other remarkable innovations in their natural history, it is perhaps not surprising that barnacles present a spectrum of opportunities for study. This symposium integrates research on barnacles in the areas of larval biology, biofouling, reproduction, biogeography, speciation, population genetics, ecological genomics, and phylogenetics. Pioneering comparisons are presented of metamorphosis among barnacles from three major lineages. Biofouling is investigated from the perspectives of biochemical and biomechanical mechanisms. Tradeoffs in reproductive specializations are scrutinized through theoretical modeling and empirical validation. Patterns of endemism and diversity are delineated in Australia and intricate species boundaries in the genus Chthamalus are elucidated for the Indo-Pacific. General methodological concerns with population expansion studies in crustaceans are highlighted using barnacle models. Data from the first, draft barnacle genome are employed to examine location-specific selection. Lastly, barnacle evolution is framed in a deep phylogenetic context and hypothetical origins of defined characters are outlined and tested.

  16. Epibiotic community on the acorn barnacle (Balanus amphitrite) from a monsoon-influenced tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Sahoo, G.; Khandeparker, L.

    associated with barnacle, Balanus amphitrite, shell and their role in gregarious settlement of cypris larvae. Journal of Experimental Marine Biology and Ecology, 413, 7- 12. Bavestrello, G., C. Bianchi, B. Calcinai, R. Cattaneo-Vietti, C. Cerrano, C. Morri...

  17. Effect of sponge ball cleaning on removing barnacles in condenser tubes

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, K; Minamoto, K; Kyohara, S [Kobe Steel Ltd. (Japan)

    1977-07-01

    Considering environmental protection, the recent tendency has been to give up chlorination of cooling water for power stations. The experimental results show that cooling sea-water without chlorination cannot get rid of barnacles which grow inside condenser tubes when the speed of the cooling water is less than 1 m/s. Cleaning by sponge balls 2 -- 3 times a week is found to be effective for both barnacle prevention and inactive film formation on the tube surface.

  18. Migrations of California gray whales tracked by oxygen-18 variations in their epizoic barnacles

    International Nuclear Information System (INIS)

    Killingley, J.S.

    1980-01-01

    Barnacles attached to the California gray whale have oxygen isotope compositions that serve as a record of changing ocean temperatures as the whale migrates between arctic and subtropical waters. The isotopic values for the barnacles can be used to track whale migrations and to reconstruct the recent movements of beached whales. The method may be useful for tracing the movements of other animals, living or fossil, and for reconstructing the voyages of ancient ships

  19. Species-specific detection and quantification of common barnacle larvae from the Japanese coast using quantitative real-time PCR.

    Science.gov (United States)

    Endo, Noriyuki; Sato, Kana; Matsumura, Kiyotaka; Yoshimura, Erina; Odaka, Yukiko; Nogata, Yasuyuki

    2010-11-01

    Species-specific detection and quantification methods for barnacle larvae using quantitative real-time polymerase chain reaction (qPCR) were developed. Species-specific primers for qPCR were designed for 13 barnacle species in the mitochondrial 12S ribosomal RNA gene region. Primer specificity was examined by PCR using template DNA extracted from each of the 13 barnacle species, other unidentified barnacle species, and field collected zooplankton samples. The resulting PCR products comprised single bands following agarose gel electrophoresis when the templates corresponded to primers. The amplifications were highly species-specific even for the field plankton samples. The field plankton samples were subjected to qPCR assay. The calculated DNA contents for each barnacle species were closely correlated with the number of larvae measured by microscopic examination. The method could be applied to quantify barnacle larvae in natural plankton samples.

  20. Worldwide genetic differentiation in the common fouling barnacle, Amphibalanus amphitrite

    KAUST Repository

    Chen, Hsi-Nien

    2014-10-21

    © 2014, © 2014 Taylor & Francis. Amphibalanus amphitrite is a common fouling barnacle distributed globally in tropical and subtropical waters. In the present study, the genetic (mitochondrial cytochrome oxidase subunit I) and morphological differentiation in A. amphitrite from 25 localities around the world were investigated. The results revealed three clades within A. amphitrite with a genetic divergence of ~ 4% among clades, whereas there were no diagnostic morphological differences among clades. Clade 1 is widely distributed in both temperate and tropical waters, whereas Clade 3 is currently restricted to the tropical region. The deep divergence among clades suggests historical isolation within A. amphitrite; thus, the present geographical overlaps are possibly a result of the combined effects of rising sea level and human-mediated dispersals. This study highlights the genetic differentiation that exists in a common, widely distributed fouling organism with great dispersal potential; future antifouling research should take into account the choice of lineages.

  1. Barnacle geese achieve significant energetic savings by changing posture.

    Directory of Open Access Journals (Sweden)

    Peter G Tickle

    Full Text Available Here we report the resting metabolic rate in barnacle geese (Branta leucopsis and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy consumption of hindlimb postural muscles when sitting, we hypothesise that a change in breathing mechanics represents one potential mechanism for at least part of the observed difference in energetic cost. Due to the significant effect of posture, future studies of resting metabolic rates need to take into account and/or report differences in posture.

  2. Barnacle geese achieve significant energetic savings by changing posture.

    Science.gov (United States)

    Tickle, Peter G; Nudds, Robert L; Codd, Jonathan R

    2012-01-01

    Here we report the resting metabolic rate in barnacle geese (Branta leucopsis) and provide evidence for the significant energetic effect of posture. Under laboratory conditions flow-through respirometry together with synchronous recording of behaviour enabled a calculation of how metabolic rate varies with posture. Our principal finding is that standing bipedally incurs a 25% increase in metabolic rate compared to birds sitting on the ground. In addition to the expected decrease in energy consumption of hindlimb postural muscles when sitting, we hypothesise that a change in breathing mechanics represents one potential mechanism for at least part of the observed difference in energetic cost. Due to the significant effect of posture, future studies of resting metabolic rates need to take into account and/or report differences in posture.

  3. Antifouling Activity of Synthetic Alkylpyridinium Polymers Using the Barnacle Model

    Science.gov (United States)

    Piazza, Veronica; Dragić, Ivanka; Sepčić, Kristina; Faimali, Marco; Garaventa, Francesca; Turk, Tom; Berne, Sabina

    2014-01-01

    Polymeric alkylpyridinium salts (poly-APS) isolated from the Mediterranean marine sponge, Haliclona (Rhizoniera) sarai, effectively inhibit barnacle larva settlement and natural marine biofilm formation through a non-toxic and reversible mechanism. Potential use of poly-APS-like compounds as antifouling agents led to the chemical synthesis of monomeric and oligomeric 3-alkylpyridinium analogues. However, these are less efficient in settlement assays and have greater toxicity than the natural polymers. Recently, a new chemical synthesis method enabled the production of poly-APS analogues with antibacterial, antifungal and anti-acetylcholinesterase activities. The present study examines the antifouling properties and toxicity of six of these synthetic poly-APS using the barnacle (Amphibalanus amphitrite) as a model (cyprids and II stage nauplii larvae) in settlement, acute and sub-acute toxicity assays. Two compounds, APS8 and APS12-3, show antifouling effects very similar to natural poly-APS, with an anti-settlement effective concentration that inhibits 50% of the cyprid population settlement (EC50) after 24 h of 0.32 mg/L and 0.89 mg/L, respectively. The toxicity of APS8 is negligible, while APS12-3 is three-fold more toxic (24-h LC50: nauplii, 11.60 mg/L; cyprids, 61.13 mg/L) than natural poly-APS. This toxicity of APS12-3 towards nauplii is, however, 60-fold and 1200-fold lower than that of the common co-biocides, Zn- and Cu-pyrithione, respectively. Additionally, exposure to APS12-3 for 24 and 48 h inhibits the naupliar swimming ability with respective IC50 of 4.83 and 1.86 mg/L. PMID:24699112

  4. Antifouling Activity of Synthetic Alkylpyridinium Polymers Using the Barnacle Model

    Directory of Open Access Journals (Sweden)

    Veronica Piazza

    2014-04-01

    Full Text Available Polymeric alkylpyridinium salts (poly-APS isolated from the Mediterranean marine sponge, Haliclona (Rhizoniera sarai, effectively inhibit barnacle larva settlement and natural marine biofilm formation through a non-toxic and reversible mechanism. Potential use of poly-APS-like compounds as antifouling agents led to the chemical synthesis of monomeric and oligomeric 3-alkylpyridinium analogues. However, these are less efficient in settlement assays and have greater toxicity than the natural polymers. Recently, a new chemical synthesis method enabled the production of poly-APS analogues with antibacterial, antifungal and anti-acetylcholinesterase activities. The present study examines the antifouling properties and toxicity of six of these synthetic poly-APS using the barnacle (Amphibalanus amphitrite as a model (cyprids and II stage nauplii larvae in settlement, acute and sub-acute toxicity assays. Two compounds, APS8 and APS12-3, show antifouling effects very similar to natural poly-APS, with an anti-settlement effective concentration that inhibits 50% of the cyprid population settlement (EC50 after 24 h of 0.32 mg/L and 0.89 mg/L, respectively. The toxicity of APS8 is negligible, while APS12-3 is three-fold more toxic (24-h LC50: nauplii, 11.60 mg/L; cyprids, 61.13 mg/L than natural poly-APS. This toxicity of APS12-3 towards nauplii is, however, 60-fold and 1200-fold lower than that of the common co-biocides, Zn- and Cu-pyrithione, respectively. Additionally, exposure to APS12-3 for 24 and 48 h inhibits the naupliar swimming ability with respective IC50 of 4.83 and 1.86 mg/L.

  5. Spatial and temporal variability in recruitment of intertidal mussels ...

    African Journals Online (AJOL)

    . Arthur H. Dye ... Most benthic invertebrates have a pelagic larval stage. R eprodu ...... reproductive output of the acorn barnacle Semibalanus balanoides. Mar. .... juvenile survival of seven co-occurring species of sessile marine invertebrates.

  6. Invasion and morphological variation of the non-indigenous barnacle Chthamalus challengeri (Hoek, 1883) in Yangshan Port and its surrounding areas

    Science.gov (United States)

    Liu, Yan; Xue, Junzeng; Lin, Junda; Wu, Huixian

    2015-06-01

    Invasive species generally possess unique characteristics that allow them to survive the invasion process in order to establish and spread in new habitats. Successful invaders must resist both physical and physiological stresses associated with the changing environment. A common littoral barnacle, Chthamalus challengeri Hoek, 1883 (Crustacea, Cirripedia), which is native to Japan, South Korea and northern China, has become established in the high-littoral zone adjacent to Yangshan Port, Shanghai, China. A comparison of the morphology of Chthamlus species from Zhoushan archipelago with previous description indicates the occurrence of C. challengeri. The new immigrant becomes a dominant species in certain high-intertidal habitats of the adjacent area to of Yangshan Port. C. challengeri was found in part of sampling sites in Zhoushan in 2010; however, it dispersed to all the eleven sampling sites in 2012. Densities of C.challengeri had increased over 10 times in the last 2 years, with the highest mean value reaching 39533 ± 6243 ind. m-2 in the new habitat. The specific ratios of both operculum area ( Sa) to base area ( SA) and average height of parietal plates ( H) to length of base ( L) revealed that C. challengeri displays morphological changes to resist stronger currents in the new habitats for invasion.

  7. Maturation, fecundity, and intertidal spawning of Pacific sand lance in the northern Gulf of Alaska

    Science.gov (United States)

    Robards, Martin D.; Piatt, John F.; Rose, G.A.

    1999-01-01

    Pacific sand lance Ammodytes hexapterus in Kachemak Bay, Alaska, showed no sexual dimorphism in length-to-weight (gonad-free) ratio or length-at-age relationship. Most matured in their second year, males earlier in the season than females, but females (31%) attained a higher gonadosomatic index than males (21%). Sand lance spawned intertidally once each year in late September and October on fine gravel or sandy beaches soon after the seasonal peak in water temperatures. Sand lance in Cook Inlet and Prince William Sound displayed similar maturation schedules. Schools were dominated 2: 1 by males as they approached the intertidal zone at a site where spawning has taken place for decades. Sand lance spawned vigorously in dense formations, leaving scoured pits in beach sediments. Fecundity of females (93–199 mm) was proportional to length, ranging from 1468 to 16 081 ova per female. About half of the overall spawning school fecundity was derived from age group 1 females (55% of the school by number). Spawned eggs were 1·02 mm in diameter, demersal, slightly adhesive, and deposited in the intertidal just below the waterline. Sand lance embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures.

  8. Morphometric and molecular identification of individual barnacle cyprids from wild plankton

    DEFF Research Database (Denmark)

    Chen, Hsi-Nien; Høeg, Jens Thorvald; Chan, Benny K.K.

    2013-01-01

    species. Sequences from a total of 540 individual cypris larvae from Taiwanese waters formed 36 monophyletic clades (species) in a phylogenetic tree. Of these clades, 26 were identified to species, but 10 unknown monophyletic clades represented non-native species. Cyprids of the invasive barnacle......The present study used DNA barcodes to identify individual cyprids to species. This enables accurate quantification of larvae of potential fouling species in the plankton. In addition, it explains the settlement patterns of barnacles and serves as an early warning system of unwanted immigrant......, Megabalanus cocopoma, were identified. Multivariate analysis of antennular morphometric characters revealed three significant clusters in a nMDS plot, viz. a bell-shaped attachment organ (most species), a shoe-shaped attachment organ (some species), and a spear-shaped attachment organ (coral barnacles only...

  9. Nitrous oxide emissions from estuarine intertidal sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Klaver, G.; Nieuwenhuize, J.; Markusse, R.M.; Vlug, T.; Nat, F.J.W.A. van der

    1995-01-01

    From September 1990 through December 1991 nitrous oxide flux measurements were made at 9 intertidal mud flat sites in the Scheldt Estuary. Nitrous oxide release rates were highly variable both between sites and over time at any one site. Annual nitrous oxide fluxes vary from about 10 mmol N m-2 at

  10. Field spectroscopy of estuarine intertidal habitats

    NARCIS (Netherlands)

    Forster, R.M.; Jesus, B.

    2006-01-01

    The recent introduction of portable, low‐cost hyperspectral radiometers for measuring the reflectance of marine intertidal habitats has considerable promise, first as a source of reference spectra for airborne and satellite remote sensing, and second as a survey technique in its own right. This

  11. Do intertidal flats ever reach equilibrium?

    NARCIS (Netherlands)

    Maan, D.C.; van Prooijen, B.C.; Wang, Z.B.; de Vriend, H.J.

    2015-01-01

    Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the

  12. Destabilization of cohesive intertidal sediments by infauna

    NARCIS (Netherlands)

    De Deckere, E.; Tolhurst, T.J.; de Brouwer, J.F.C.

    2001-01-01

    Bioturbation activity was reduced in four plots on an intertidal mudflat in the Humber estuary (UK) during 4 days, by spraying the sediment with an insecticide, namely vydate. Macrofaunal, especially Nereis diversicolor and oligochaeta, and meiofaunal densities decreased, while the diatom biomass

  13. Proportionality for Military Leaders

    National Research Council Canada - National Science Library

    Brown, Gary D

    2000-01-01

    .... Especially lacking is a realization that there are four distinct types of proportionality. In determining whether a particular resort to war is just, national leaders must consider the proportionality of the conflict (i.e...

  14. Effects of predation risk on site selection of barnacle geese during brood-rearing

    NARCIS (Netherlands)

    Stahl, J; Loonen, MJJE; Mehlum, F; Black, JM; Madsen, J

    1998-01-01

    Barnacle geese Branta leucopsis breed on small islands in the Kongsfjorden area, Spitsbergen. Shortly after hatching, families approach feeding sites at the mainland coast in the close surroundings of the village Ny-Alesund. The goslings are subject to predation by arctic foxes Alopex lagopus

  15. Response of cyprid specific genes to natural settlement cues in the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Li, Honglei; Thiyagarajan, Vengatesen; Qian, Pei Yuan

    2010-01-01

    Quantitative real-time PCR was used to further our understanding of the molecular processes involved in the attachment and metamorphosis of larval barnacles. We report the effects of natural settlement cues (microbial biofilms and conspecific settlement-inducing factor) on the expression profiles of six barnacle cyprid specific (bcs) genes in cyprids of the barnacle Balanus (=Amphibalanus) amphitrite Darwin. Genes bcs-1 to bcs-5 all showed marked decreases in their expression between initial cyprid attachment and the completion of metamorphosis, whereas bcs-6 showed significant up-regulation. Generally, settlement cues exerted no significant effect on the decreasing trend of bcs-1 to bcs-5 expression during attachment and metamorphosis. However, the expression of bcs-6 increased prior to cyprid attachment in response to both settlement cues. This elevated expression of bcs-6 gene indicates the importance and key regulatory role of this specific gene to larval attachment and metamorphosis in this barnacle species. © 2010 Elsevier B.V. All rights reserved.

  16. Response of cyprid specific genes to natural settlement cues in the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Li, Honglei

    2010-06-01

    Quantitative real-time PCR was used to further our understanding of the molecular processes involved in the attachment and metamorphosis of larval barnacles. We report the effects of natural settlement cues (microbial biofilms and conspecific settlement-inducing factor) on the expression profiles of six barnacle cyprid specific (bcs) genes in cyprids of the barnacle Balanus (=Amphibalanus) amphitrite Darwin. Genes bcs-1 to bcs-5 all showed marked decreases in their expression between initial cyprid attachment and the completion of metamorphosis, whereas bcs-6 showed significant up-regulation. Generally, settlement cues exerted no significant effect on the decreasing trend of bcs-1 to bcs-5 expression during attachment and metamorphosis. However, the expression of bcs-6 increased prior to cyprid attachment in response to both settlement cues. This elevated expression of bcs-6 gene indicates the importance and key regulatory role of this specific gene to larval attachment and metamorphosis in this barnacle species. © 2010 Elsevier B.V. All rights reserved.

  17. Gooseneck barnacles (Lepas spp. ingest microplastic debris in the North Pacific Subtropical Gyre

    Directory of Open Access Journals (Sweden)

    Miriam C. Goldstein

    2013-10-01

    Full Text Available Substantial quantities of small plastic particles, termed “microplastic,” have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the “rafting assemblage,” are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp., which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem.

  18. Involvement of reactive oxygen species in the electrochemical inhibition of barnacle (Amphibalanus amphitrite) settlement

    Science.gov (United States)

    Rodolfo E. Perez-Roa; Marc A. Anderson; Dan Rittschof; Christopher G. Hunt; Daniel R. Noguera

    2009-01-01

    The role of reactive oxygen species (ROS) in electrochemical biofouling inhibition was investigated using a series of abiotic tests and settlement experiments with larvae of the barnacle Amphibalanus amphitrite, a cosmopolitan fouler. Larval settlement, a measure of biofouling potential, was reduced from 43% ± 14% to 5% ± 6% upon the application of...

  19. Hydrocarbon pollutants alter short-term recruitment in the barnacle Balanus eburneus

    International Nuclear Information System (INIS)

    McCoy, D.L.; Brown, K.M.

    1998-01-01

    We examined barnacle recruitment to oil-treated clay tiles at two coastal and two protected sites along the Louisiana coast. Tiles exposed to crude oil and its water-soluble fraction (WSF) had diminished barnacle recruitment after 3 weeks, in comparison with non-treated tiles. Effects were most obvious at the exposed coastal sites. After a 6-week immersion, however, treatment effects were no longer consistent. In later experiments, Balanus eburneus recruitment was higher on weathered WSF tiles (exposed, and leached in seawater before immersion in the field) than on WSF tiles, but not different from control tiles. Hydrocarbons depress recruitment initially, but may be removed later by leaching or by hydrocarbon-degrading microbes, and the remaining biofilm may facilitate recruitment. While barnacle recruitment was generally higher at exposed sites, as expected from the literature, local factors caused significant variation in recruitment within exposure categories as well. Barnacles also grow to larger sizes at open-coast sites, probably because of increased water flow and planktonic food delivery. Naupliar abundances varied tremendously among sites and dates and were poor predictors of eventual recruitment. (author)

  20. Isolation of living Algae growing in the shells of Molluscs and Barnacles with EDTA (ethylenediaminetetraacetic acid)

    NARCIS (Netherlands)

    Prud’homme van Reine, W.F.; Hoek, van den C.

    1966-01-01

    Several decalcifying mixtures or aqueous solutions of inorganic or organic acids are generally used for releasing algae growing in the shells of molluscs and barnacles, for instance dilute hydrochloric, nitric, citric, or acetic acid (4), a mixture of nitric acid, chromic acid and alcolhol (1),

  1. Cypris morphology in the barnacles Ibla and Paralepas (Crustacea: Cirripedia Thoracica) implications for cirripede evolution

    DEFF Research Database (Denmark)

    Høeg, Jens T; Achituv, Yair; Chan, Benny K K

    2009-01-01

    We used scanning electron microscopy (SEM) to describe cypris morphology in species of the barnacles Ibla and Paralepas, both of which are pivotal in understanding cirripede evolution. In Ibla, we also studied late naupliar stages with video and SEM. Special emphasis was put on the lattice organs...

  2. Growth and molting in epizoic pedunculate barnacles genus Octolasmis (Crustacea: Thecostraca: Cirripedia: Thoracica)

    DEFF Research Database (Denmark)

    Blomsterberg, Mikkel; Glenner, Henrik; Høeg, Jens T

    2004-01-01

    Scanning electron microscopy, light microscopy, and histology were used to study growth in species of the pedunculate barnacle genus Octolasmis (O. angulata, O. cor, O. californiana, O. mülleri). These species are epizoic in the gill chamber of portunid crabs and have highly reduced capitular she...

  3. Body size declines despite positive directional selection on heritable size traits in a barnacle goose population

    NARCIS (Netherlands)

    Larsson, K; van der Jeugd, HP; van der Veen, IT; Forslund, P

    Analyses of more than 2000 marked barnacle geese (Branta leucopsis) in the largest Baltic colony, Sweden, showed that structurally large females generally produced larger clutches and larger eggs, hatched their broods earlier in the season, and produced more and heavier-young than smaller females.

  4. The morphological development of the locomotor and cardiac muscles of the migratory barnacle goose (Branta leucopsis)

    NARCIS (Netherlands)

    Bishop, CM; Butler, PJ; ElHaj, AJ; Egginton, S; Loonen, MJJE

    The masses of the locomotor and cardiac muscles of wild barnacle goose goslings, from a migratory population, were examined systematically during development and their values compared to those of pre-migratory geese. Pre-flight development was typified by approximately linear increases of body, leg,

  5. Food intake, body reserves and reproductive success of barnacle geese Branta leucopsis staging in different habitats

    NARCIS (Netherlands)

    Prop, J; Black, JM; Mehlum, F; Black, JM; Madsen, J

    1998-01-01

    This paper concerns the effect of habitat choice on the dynamics of deposition of body reserves in spring-staging barnacle geese Branta leucopsis. On their way to breeding areas in Spitsbergen, these geese reside for several weeks on islands off the coast of Helgeland, Norway. They use three

  6. Multiple origins and incursions of the Atlantic barnacle Chthamalus proteus in the Pacific.

    Science.gov (United States)

    Zardus, John D; Hadfield, Michael G

    2005-10-01

    Chthamalus proteus, a barnacle native to the Caribbean and western Atlantic, was introduced to the Pacific within the last few decades. Using direct sequencing of mitochondrial DNA (COI), we characterized genetic variation in native and introduced populations and searched for genetic matches between regions to determine if there were multiple geographical sources and introduction points for this barnacle. In the native range, we found great genetic differences among populations (max. F(ST) = 0.613) encompassing four lineages: one endemic to Panama, one endemic to Brazil, and two occurring Caribbean-wide. All four lineages were represented in the Pacific, but not equally; the Brazilian lineage was most prevalent and the Panamanian least common. Twenty-one individuals spread among nearly every island from where the barnacle is known in the Pacific, exactly matched six haplotypes scattered among Curaçao, the Netherlands Antilles; St John, US Virgin Islands; Puerto Rico; and Brazil, confirming a multigeographical origin for the Pacific populations. Significant genetic differences were also found in introduced populations from the Hawaiian Islands (F(CT) = 0.043, P < 0.001), indicating introduction events have occurred at more than one locality. However, the sequence, timing and number of arrival events remains unknown. Possible reasons for limited transport of this barnacle through the Panama Canal are discussed. This and a preponderance of Brazilian-type individuals in the Pacific suggest an unexpected route of entry from around Cape Horn, South America. Unification in the Pacific of historically divergent lineages of this barnacle raises the possibility for selection of 'hybrids' with novel ecological adaptations in its new environment.

  7. The fluid dynamics of Balanus glandula barnacles: Adaptations to sheltered and exposed habitats.

    Science.gov (United States)

    Vo, Maureen; Mehrabian, Sasan; Villalpando, Fernando; Etienne, Stephane; Pelletier, Dominique; Cameron, Christopher B

    2018-04-11

    Suspension feeders use a wide range of appendages to capture particles from the surrounding fluid. Their functioning, either as a paddle or a sieve, depends on the leakiness, or amount of fluid that passes through the gaps between the appendages. Balanus glandula is the most common species of barnacle distributed along the Pacific coast of North America. It shows a strong phenotypic response to water flow velocity. Individuals from exposed, high flow sites have short and robust cirral filters, whereas those from sheltered, low velocity sites have long, spindly appendages. Computational fluid dynamics (CFD) simulations of these two ecophenotypes were done using a finite volume method. Leakiness was determined by simulating flow velocity fields at increasing Reynolds numbers, results that have been unattainable at higher velocities by observation. CFD also allowed us to characterize flow in hard to see regions of the feeding legs (rami). Laser-illumination experiments were performed at low to medium flow velocities in a flume tank and corroborated results from CFD. Barnacle filters from a sheltered site become completely leaky at Re=2.24(0.16m/s), well above the maximum habitat velocity, suggesting that this ecophenotype is not mechanically optimized for feeding. Barnacles from exposed environments become fully leaky within the range of habitat velocities Re=3.50(0.18m/s). Our CFD results revealed that the drag force on exposed barnacles feeding appendages are the same as the sheltered barnacles feeding appendages despite their shape difference and spacing ratio. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. The Principle of Proportionality

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Meisner Nielsen, Kasper

    2005-01-01

    Recent policy initiatives within the harmonization of European company laws have promoted a so-called "principle of proportionality" through proposals that regulate mechanisms opposing a proportional distribution of ownership and control. We scrutinize the foundation for these initiatives...... in relationship to the process of harmonization of the European capital markets.JEL classifications: G30, G32, G34 and G38Keywords: Ownership Structure, Dual Class Shares, Pyramids, EU companylaws....

  9. The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Zhang, Y.

    2012-08-01

    The barnacle Balanus amphitrite is among the most dominant fouling species on intertidal rocky shores in tropical and subtropical areas and is thus a target organism in antifouling research. After being released from adults, the swimming nauplius undertakes six molting cycles and then transforms into a cyprid. Using paired antennules, a competent cyprid actively explores and selects a suitable substratum for attachment and metamorphosis (collectively known as settlement). This selection process involves the reception of exogenous signals and subsequent endogenous signal transduction. To investigate the involvement of nitric oxide (NO) and cyclic GMP (cGMP) during larval settlement of B. amphitrite, we examined the effects of an NO donor and an NO scavenger, two nitric oxide synthase (NOS) inhibitors and a soluble guanylyl cyclase (sGC) inhibitor on settling cyprids. We found that the NO donor sodium nitroprusside (SNP) inhibited larval settlement in a dose-dependent manner. In contrast, both the NO scavenger carboxy-PTIO and the NOS inhibitors aminoguanidine hemisulfate (AGH) and S-methylisothiourea sulfate (SMIS) significantly accelerated larval settlement. Suppression of the downstream guanylyl cyclase (GC) activity using a GC-selective inhibitor ODQ could also significantly accelerate larval settlement. Interestingly, the settlement inhibition effects of SNP could be attenuated by ODQ at all concentrations tested. In the developmental expression profiling of NOS and sGC, the lowest expression of both genes was detected in the cyprid stage, a crucial stage for the larval decision to attach and metamorphose. In summary, we concluded that NO regulates larval settlement via mediating downstream cGMP signaling.

  10. The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Zhang, Y.; He, L.-S.; Zhang, G.; Xu, Y.; Lee, O.-O.; Matsumura, K.; Qian, P.-Y.

    2012-01-01

    The barnacle Balanus amphitrite is among the most dominant fouling species on intertidal rocky shores in tropical and subtropical areas and is thus a target organism in antifouling research. After being released from adults, the swimming nauplius undertakes six molting cycles and then transforms into a cyprid. Using paired antennules, a competent cyprid actively explores and selects a suitable substratum for attachment and metamorphosis (collectively known as settlement). This selection process involves the reception of exogenous signals and subsequent endogenous signal transduction. To investigate the involvement of nitric oxide (NO) and cyclic GMP (cGMP) during larval settlement of B. amphitrite, we examined the effects of an NO donor and an NO scavenger, two nitric oxide synthase (NOS) inhibitors and a soluble guanylyl cyclase (sGC) inhibitor on settling cyprids. We found that the NO donor sodium nitroprusside (SNP) inhibited larval settlement in a dose-dependent manner. In contrast, both the NO scavenger carboxy-PTIO and the NOS inhibitors aminoguanidine hemisulfate (AGH) and S-methylisothiourea sulfate (SMIS) significantly accelerated larval settlement. Suppression of the downstream guanylyl cyclase (GC) activity using a GC-selective inhibitor ODQ could also significantly accelerate larval settlement. Interestingly, the settlement inhibition effects of SNP could be attenuated by ODQ at all concentrations tested. In the developmental expression profiling of NOS and sGC, the lowest expression of both genes was detected in the cyprid stage, a crucial stage for the larval decision to attach and metamorphose. In summary, we concluded that NO regulates larval settlement via mediating downstream cGMP signaling.

  11. Intertidal deposits: river mouths, tidal flats, and coastal lagoons

    NARCIS (Netherlands)

    Eisma, D.; Boer, de P.L.; Cadee, G.C.; Dijkema, K.; Ridderinkhof, H.; Phillippart, C.

    1998-01-01

    Intertidal Deposits: River Mouths, Tidal Flats, and Coastal Lagoons combines the authors personal and professional experience with the mass of available literature to present a cohesive overview of intertidal deposits and the widely diverse conditions of their formation worldwide. This includes the

  12. Large-Scale Spatial Dynamics of Intertidal Mussel (

    NARCIS (Netherlands)

    Folmer, E.O.; Drent, J.; Troost, K.; Büttger, H.; Dankers, N.; Jansen, J.; van Stralen, M.; Millat, G.; Herlyn, M.; Philippart, C.J.M.

    2014-01-01

    Intertidal blue mussel beds are important for the functioning and community composition of coastal ecosystems. Modeling spatial dynamics of intertidal mussel beds is complicated because suitable habitat is spatially heterogeneously distributed and recruitment and loss are hard to predict. To get

  13. Recolonization of experimentally defaunated tidepools by northeast Pacific intertidal fishes.

    Science.gov (United States)

    K.M. Polivka; M.A. Chotkowski

    1998-01-01

    Site fidelity and maintenance of home ranges are common in fishes (e.g., Stephens et al., 1970; Robertson and Sheldon, 1979; Hixon, 1981), especially for intertidal species for which the ability to navigate to a safe region of an environment that periodically drains of water may be adaptive (e.g., Gibson 1967, 1969, 1982). For intertidal fishes in the northeast Pacific...

  14. Intertidal and shallow water Cirripedia of the Caribbean

    NARCIS (Netherlands)

    Southward, A.J.

    1975-01-01

    Some 22 taxa of barnacles, including 19 Balanomorpha, are recorded from a large number of Caribbean localities, ranging from S. Florida to Trinidad, and from the Panama Canal Zone to Barbados. Balanus reticulatus Utinomi is recorded for the first time from the region and its morphology compared with

  15. Antifouling Activity of Simple Synthetic Diterpenoids against Larvae of the Barnacle Balanus albicostatus Pilsbry

    Directory of Open Access Journals (Sweden)

    Dan-Qing Feng

    2010-11-01

    Full Text Available Five new pimarane diterpenoids 1-5 were synthesized using ent-8(14-pimarene-15R,16-diol as starting material. The structures were elucidated by means of extensive NMR and MS analysis. The antifouling activity against larval settlement of the barnacle Balanus albicostatus were evaluated using capsaicin as a positive control. Compounds 1-3 and 5 showed more potent antifouling activity than capsaicin. Compound 5, which exhibited almost the same antifouling activity as starting material, showed better stability than starting material. These compounds all showed antifouling activity in a non-toxic way against larval settlement of the barnacle B. albicostatus. Analysis of structure-activity relationships (SAR demonstrated that the substituents on the C-15 and C-16 position of pimarane diterpenoid were responsible for the antifouling activity.

  16. Carbon budget of leaves of the tropical intertidal seagrass Thalassia hemprichii

    Science.gov (United States)

    Chiu, Shih-Han; Huang, Yen-Hsun; Lin, Hsing-Juh

    2013-07-01

    The question of whether seagrass beds are effective carbon sinks has recently attracted much attention. Leaf production and consumption, and detrital export and decomposition were determined to quantify the carbon budget of leaf production in a southern Taiwan seagrass bed composed of the tropical intertidal seagrass Thalassia hemprichii, which is widely distributed in intertidal zones of the western Pacific. The influence of elevation in the intertidal zone on these processes was also investigated. Leaf production and consumption, and export of leaf detritus showed seasonal variations, with higher rates in the wet season (summer and autumn) and lower rates in the dry season (winter and spring). At the high-elevation site, leaf consumption by fish was significantly higher than that by sea urchins. At the low-elevation site, however, the proportion of leaves consumed by sea urchins was equivalent to that by fish. Leaf detritus decomposed rapidly within the first 9 days, then gradually slowed down, and stabilised after 212 days, at which only 8.7% of dry weight remained in the litterbags. The carbon budget of seagrass leaves demonstrated that 20% of leaf production was grazed by fish and sea urchins and 80% flowed to detritus. This suggests that seagrass leaves are important food sources for inhabiting herbivores. Most of the detritus decomposed (44% of leaf production) or was exported (32% of leaf production), and only 4% of leaf production or 22 g C m-2 yr-1 was stored in this tropical intertidal seagrass bed. Mass balance calculations support this tropical seagrass bed acting as a carbon sink and an outwelling system which exports organic detritus to neighboring coral reefs.

  17. Larval development, sensory mechanisms and physiological adaptions in acorn barnacles with special reference to Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Khandeparker, L.; Desai, D.V.; Baragi, L.V.; Gaonkar, C.

    . It was pointed out that generally, during late autumn to early spring, less food is available for adults; hence, retention of egg mass within the adult would be at the cost of its nutritional status (Anil et al., 1995). Thus, in balanomorph barnacles energy... resulted from the combined benefits of increased phytoplankton, zooplankton, and warmer water temperatures. In turn they suggested that it is important to incorporate the influence of zooplankton and water temperature into studies of bottom-up influences...

  18. Compounds from silicones alter enzyme activity in curing barnacle glue and model enzymes.

    Science.gov (United States)

    Rittschof, Daniel; Orihuela, Beatriz; Harder, Tilmann; Stafslien, Shane; Chisholm, Bret; Dickinson, Gary H

    2011-02-17

    Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity. GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents. Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties. Altered curing of natural glues has potential in fouling management.

  19. Correlation between surface chemistry and settlement behaviour in barnacle cyprids (Balanus improvisus).

    Science.gov (United States)

    Di Fino, A; Petrone, L; Aldred, N; Ederth, T; Liedberg, B; Clare, A S

    2014-02-01

    In laboratory-based biofouling assays, the influence of physico-chemical surface characteristics on barnacle settlement has been tested most frequently using the model organism Balanus amphitrite (= Amphibalanus amphitrite). Very few studies have addressed the settlement preferences of other barnacle species, such as Balanus improvisus (= Amphibalanus improvisus). This study aimed to unravel the effects of surface physico-chemical cues, in particular surface-free energy (SFE) and surface charge, on the settlement of cyprids of B. improvisus. The use of well-defined surfaces under controlled conditions further facilitates comparison of the results with recent similar data for B. amphitrite. Zero-day-old cyprids of B. improvisus were exposed to a series of model surfaces, namely self-assembled monolayers (SAMs) of alkanethiols with varying end-groups, homogenously applied to gold-coated polystyrene (PS) Petri dishes. As with B. amphitrite, settlement of cyprids of B. improvisus was influenced by both SFE and charge, with higher settlement on low-energy (hydrophobic) surfaces and negatively charged SAMs. Positively charged SAMs resulted in low settlement, with intermediate settlement on neutral SAMs of similar SFE. In conclusion, it is demonstrated that despite previous suggestions to the contrary, these two species of barnacle show similar preferences in response to SFE; they also respond similarly to charge. These findings have positive implications for the development of novel antifouling (AF) coatings and support the importance of consistency in substratum choice for assays designed to compare surface preferences of fouling organisms.

  20. Hydrocarbon biodegradation in intertidal wetland sediments.

    Science.gov (United States)

    McGenity, Terry J

    2014-06-01

    Intertidal wetlands, primarily salt marsh, mangrove and mudflats, which provide many essential ecosystem services, are under threat on numerous fronts; a situation that is made worse by crude-oil pollution. Microbes are the main vehicle for remediation of such sediments, and new discoveries, such as novel biodegradation pathways, means of accessing oil, multi-species interactions, and community-level responses to oil addition, are helping us to understand, predict and monitor the fate of oil. Despite this, there are many challenges, not least because of the heterogeneity of these ecosystems and the complexity of crude oil. For example, there is growing awareness about the toxicity of the oxygenated products that result from crude-oil weathering, which are difficult to degrade. This review highlights how developments in areas as diverse as systems biology, microbiology, ecology, biogeochemistry and analytical chemistry are enhancing our understanding of hydrocarbon biodegradation and thus bioremediation of oil-polluted intertidal wetlands. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Multiwire proportional chamber development

    Science.gov (United States)

    Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

    1973-01-01

    The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

  2. The influence of atmospheric cold fronts on larval supply and settlement of intertidal invertebrates: Case studies in the Cabo Frio coastal upwelling system (SE Brazil)

    Science.gov (United States)

    de Azevedo Mazzuco, Ana Carolina; Christofoletti, Ronaldo Adriano; Coutinho, Ricardo; Ciotti, Áurea Maria

    2018-07-01

    Atmospheric fronts such as cold fronts are dynamic mesoscale systems with potential effects on the ecology of marine communities. In this study, larval dynamics in subtropical rocky shore communities were evaluated under the influence of atmospheric frontal systems. The hypothesis is that these systems may promote favorable conditions for larval supply and settlement regardless of taxa or site, and that supply and settlement vary in association with fluctuations of meteorological and oceanographic conditions driven by the fronts. This study was carried out in the Southeastern Brazil littoral region under the influence of coastal upwelling events (Cabo Frio) and subject to weekly atmospheric frontal systems, cold polar fronts. The spatial and temporal variability of larvae and settlers of barnacles and mussels were assessed by collecting daily samples at three sites before, during and after atmospheric cold fronts, and the atmospheric and pelagic conditions were monitored. Contrasts among rates, events and sites were tested using discriminant function analysis, analyses of variance and correlation analysis. Atmospheric frontal systems were considered to influence the sites when wind direction changed to SW-S-SE and persisted for at least a day, and waves from SW-SW-SE increased in height. The results corroborate the hypothesis that cold fronts are important regulators of larval dynamics and intertidal communities on rocky shores of the studied area. Both larval supply and settlement were highly correlated with fluctuations in wind speed and direction. Higher settlement rates of barnacles occurred one-day prior, or on the onset of cold fronts. Mussels species tended to settle during all conditions, but on average, settlement rates were higher during the cold fronts. Some temporal trends were site specific and variability was detected among taxa and larval stages. Our findings suggest that mesoscale oceanographic/atmospheric systems are particularly relevant on the

  3. Restrictions and Proportionality

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2009-01-01

    The article discusses three central aspects of the freedoms under European Community law, namely 1) the prohibition against restrictions as an important extension of the prohibition against discrimination, 2) a prohibition against exit restrictions which is just as important as the prohibition...... against host country restrictions, but which is often not recognised to the same extent by national law, and 3) the importance of also identifying and recognising an exit restriction, so that it is possible to achieve the required test of appropriateness and proportionality in relation to the rule...

  4. The divine proportion

    CERN Document Server

    Huntley, H E

    1970-01-01

    Using simple mathematical formulas, most as basic as Pythagoras's theorem and requiring only a very limited knowledge of mathematics, Professor Huntley explores the fascinating relationship between geometry and aesthetics. Poetry, patterns like Pascal's triangle, philosophy, psychology, music, and dozens of simple mathematical figures are enlisted to show that the ""divine proportion"" or ""golden ratio"" is a feature of geometry and analysis which awakes answering echoes in the human psyche. When we judge a work of art aesthetically satisfying, according to his formulation, we are making it c

  5. Plastic and other microfibers in sediments, macroinvertebrates and shorebirds from three intertidal wetlands of southern Europe and west Africa.

    Science.gov (United States)

    Lourenço, Pedro M; Serra-Gonçalves, Catarina; Ferreira, Joana Lia; Catry, Teresa; Granadeiro, José P

    2017-12-01

    Microplastics are widespread in aquatic environments and can be ingested by a wide range of organisms. They can also be transferred along food webs. Estuaries and other tidal wetlands may be particularly prone to this type of pollution due to their particular hydrological characteristics and sewage input, but few studies have compared wetlands with different anthropogenic pressure. Furthermore, there is no information on microplastic transfer to secondary intertidal consumers such as shorebirds. We analysed intertidal sediments, macroinvertebrates and shorebirds, from three important wetlands along the Eastern Atlantic (Tejo estuary, Portugal; Banc d'Arguin, Mauritania and Bijagós archipelago, Guinea-Bissau), in order to evaluate the prevalence and transfer of microplastics along the intertidal food web. We further investigated variables that could explain the distribution of microplastics within the intertidal areas of the Tejo estuary. Microfibers were recorded in a large proportion of sediment samples (91%), macroinvertebrates (60%) and shorebird faeces (49%). μ-FTIR analysis indicated only 52% of these microfibers were composed of synthetic polymers (i.e. plastics). Microfiber concentrations were generally higher in the Tejo and lower in the Bijagós, with intermediate values for Banc d'Arguin, thus following a latitudinal gradient. Heavier anthropogenic pressure in the Tejo explains this pattern, but the relatively high concentrations in a pristine site like the Banc d'Arguin demonstrate the spread of pollution in the oceans. Similar microfiber concentrations in faeces of shorebirds with different foraging behaviour and similar composition of fibres collected from invertebrate and faeces suggest shorebirds mainly ingest microfibers through their prey, confirming microfiber transfer along intertidal food webs. Within the Tejo estuary, concentration of microfibers in the sediment and bivalves were positively related with the percentage of fine sediments and

  6. Transport processes in intertidal sand flats

    Science.gov (United States)

    Wu, Christy

    2010-05-01

    Methane rich sulfate depleted seeps are observed along the low water line of the intertidal sand flat Janssand in the Wadden Sea. It is unclear where in the flat the methane is formed, and how it is transported to the edge of the sand flat where the sulfidic water seeps out. Methane and sulfate distributions in pore water were determined along transects from low water line toward the central area of the sand flat. The resulting profiles showed a zone of methane-rich and sulfate-depleted pore water below 2 m sediment depth. Methane production and sulfate reduction are monitored over time for surface sediments collected from the upper flat and seeping area. Both activities were at 22 C twice as high as at 15 C. The rates in sediments from the central area were higher than in sediments from the methane seeps. Methanogenesis occurred in the presence of sulfate, and was not significantly accelerated when sulfate was depleted. The observations show a rapid anaerobic degradation of organic matter in the Janssand. The methane rich pore water is obviously transported with a unidirectional flow from the central area of the intertidal sand flat toward the low water line. This pore water flow is driven by the pressure head caused by elevation of the pore water relative to the sea surface at low tide (Billerbeck et al. 2006a). The high methane concentration at the low water line accumulates due to a continuous outflow of pore water at the seepage site that prevents penetration of electron acceptors such as oxygen and sulfate to reoxidize the reduced products of anaerobic degradation (de Beer et al. 2006). It is, however, not clear why no methane accumulates or sulfate is depleted in the upper 2 m of the flats.

  7. Enhancement of local species richness in tundra by seed dispersal through guts of muskox and barnacle goose

    DEFF Research Database (Denmark)

    Bruun, Hans Henrik; Lundgren, Rebekka; Philipp, Marianne

    2008-01-01

    The potential contribution of vertebrate-mediated seed rain to the maintenance of plant community richness in a High Arctic ecosystem was investigated. We analyzed viable seed content in dung of the four numerically most important terrestrial vertebrates in Northeast Greenland - muskox (Ovibos...... moschatus), barnacle goose (Branta leucopsis), Arctic fox (Alopex lagopus) and Arctic hare (Lepus arcticus). High numbers of plant propagules were found in the dung of muskox and barnacle goose. Seeds of many plant species were found in the faeces of one vertebrate species only. Propagule composition...... in barnacle goose droppings was relatively uniform over samples, with a high abundance of the nutritious bulbils of Polygonum viviparum (Bistorta vivipara), suggesting that geese have a narrow habitat preference and feed selectively. Propagule composition in muskox dung was diverse and heterogeneous among...

  8. Development of an intertidal mangrove nursery and afforestation techniques

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.

    The development of an intertidal mangrove nursery and afforestation technique for regeneration and restoration of mangroves of Goa is described. Site selection, source of plant material, nursery plantation, season of transplantation, technique...

  9. Ecology of intertidal benthic algae of Northern Karnataka coast

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.; Reddy, C.R.K.; Deshmukhe, G.V.

    The intertidal benthic marine algal flora has been studied for distribution, phenology, biomass and zonation along with the environmental conditions. About 65 species belonging to 42 genera of Chlorophyta, Phaeophyta have been recorded. Rhodophyta...

  10. Massarina armatispora sp. nov., a new intertidal ascomycete from mangroves

    Digital Repository Service at National Institute of Oceanography (India)

    Hyde, K.D.; Vrijmoed, L.L.P.; Chinnaraj, S.; Jones, E.B.G.

    Massarina armatispora sp. nov. is described from dead intertidal mangrove wood collected in India and Hong Kong. The new taxon is compared with other M. species, and its placement in the genus Massarina is discussed...

  11. Petroleum hydrocarbons in intertidal ecosystem along the Bombay Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, S.A.; Kadam, A.N.; Mayadeo, M.S.; Dhadke, P.M.

    of petroleum hydrocarbons (153.8 mu g.l sup(-1) in water sample collected near an outfall indicated that the intertidal ecosystem of Worli might be contaminated by the effluent discharges from the onshore industrial unit...

  12. A nuclear proportional counter

    International Nuclear Information System (INIS)

    1973-01-01

    The invention relates to a nuclear proportional counter comprising in a bulb filled with a low-pressure gas, a wire forming an anode and a cathode, characterized in that said cathode is constituted by two plane plates parallel to each other and to the anode wire, and in that two branches of a circuit are connected to the anode wire end-portions, each branch comprising a pre-amplifier, a measuring circuit consisting of a differentiator-integrator-differentiator amplifier and a zero detector, one of the branches comprising an adjustable delay circuit, both branches jointly attacking a conversion circuit for converting the pulse duration into amplitudes said conversion circuit being followed by a multi-channel analyzer, contingently provided with a recorder [fr

  13. Load proportional safety brake

    Science.gov (United States)

    Cacciola, M. J.

    1979-01-01

    This brake is a self-energizing mechanical friction brake and is intended for use in a rotary drive system. It incorporates a torque sensor which cuts power to the power unit on any overload condition. The brake is capable of driving against an opposing load or driving, paying-out, an aiding load in either direction of rotation. The brake also acts as a no-back device when torque is applied to the output shaft. The advantages of using this type of device are: (1) low frictional drag when driving; (2) smooth paying-out of an aiding load with no runaway danger; (3) energy absorption proportional to load; (4) no-back activates within a few degrees of output shaft rotation and resets automatically; and (5) built-in overload protection.

  14. Macroeconomic Proportions and Corellations

    Directory of Open Access Journals (Sweden)

    Constantin Anghelache

    2006-02-01

    Full Text Available The work is focusing on the main proportions and correlations which are being set up between the major macroeconomic indicators. This is the general frame for the analysis of the relations between the Gross Domestic Product growth rate and the unemployment rate; the interaction between the inflation rate and the unemployment rate; the connection between the GDP growth rate and the inflation rate. Within the analysis being performed, a particular attention is paid to �the basic relationship of the economic growth� by emphasizing the possibilities as to a factorial analysis of the macroeconomic development, mainly as far as the Gross Domestic Product is concerned. At this point, the authors are introducing the mathematical relations, which are used for modeling the macroeconomic correlations, hence the strictness of the analysis being performed.

  15. Macroeconomic Proportions and Corellations

    Directory of Open Access Journals (Sweden)

    Constantin Mitrut

    2006-04-01

    Full Text Available The work is focusing on the main proportions and correlations which are being set up between the major macroeconomic indicators. This is the general frame for the analysis of the relations between the Gross Domestic Product growth rate and the unemployment rate; the interaction between the inflation rate and the unemployment rate; the connection between the GDP growth rate and the inflation rate. Within the analysis being performed, a particular attention is paid to “the basic relationship of the economic growth” by emphasizing the possibilities as to a factorial analysis of the macroeconomic development, mainly as far as the Gross Domestic Product is concerned. At this point, the authors are introducing the mathematical relations, which are used for modeling the macroeconomic correlations, hence the strictness of the analysis being performed.

  16. Theme and variations: amphibious air-breathing intertidal fishes.

    Science.gov (United States)

    Martin, K L

    2014-03-01

    Over 70 species of intertidal fishes from 12 families breathe air while emerging from water. Amphibious intertidal fishes generally have no specialized air-breathing organ but rely on vascularized mucosae and cutaneous surfaces in air to exchange both oxygen and carbon dioxide. They differ from air-breathing freshwater fishes in morphology, physiology, ecology and behaviour. Air breathing and terrestrial activity are present to varying degrees in intertidal fish species, correlated with the tidal height of their habitat. The gradient of amphibious lifestyle includes passive remainers that stay in the intertidal zone as tides ebb, active emergers that deliberately leave water in response to poor aquatic conditions and highly mobile amphibious skipper fishes that may spend more time out of water than in it. Normal terrestrial activity is usually aerobic and metabolic rates in air and water are similar. Anaerobic metabolism may be employed during forced exercise or when exposed to aquatic hypoxia. Adaptations for amphibious life include reductions in gill surface area, increased reliance on the skin for respiration and ion exchange, high affinity of haemoglobin for oxygen and adjustments to ventilation and metabolism while in air. Intertidal fishes remain close to water and do not travel far terrestrially, and are unlikely to migrate or colonize new habitats at present, although in the past this may have happened. Many fish species spawn in the intertidal zone, including some that do not breathe air, as eggs and embryos that develop in the intertidal zone benefit from tidal air emergence. With air breathing, amphibious intertidal fishes survive in a variable habitat with minimal adjustments to existing structures. Closely related species in different microhabitats provide unique opportunities for comparative studies. © 2013 The Fisheries Society of the British Isles.

  17. Deeply hidden inside introduced biogenic structures - Pacific oyster reefs reduce detrimental barnacle overgrowth on native blue mussels

    Science.gov (United States)

    Buschbaum, Christian; Cornelius, Annika; Goedknegt, M. Anouk

    2016-11-01

    In sedimentary coastal ecosystems shells of epibenthic organisms such as blue mussels (Mytilus edulis) provide the only major attachment surface for barnacle epibionts, which may cause detrimental effects on their mussel basibionts by e.g. reducing growth rate. In the European Wadden Sea, beds of native blue mussels have been invaded by Pacific oysters Crassostrea gigas, which transformed these beds into mixed reefs of oysters with mussels. In this study, we determined the spatial distribution of M. edulis and their barnacle epibionts (Semibalanus balanoides) within the reef matrix. Mean mussel density near the bottom was about twice as high compared to the mussel density near the top of an oyster reef, whereas barnacles on mussels showed a reversed pattern. Barnacle dry weight per mussel was on average 14 times higher near the top than at the bottom. This pattern was confirmed by experimentally placing clean M. edulis at the top and on the bottom of oyster reefs at two sites in the Wadden Sea (island of Texel, The Netherlands; island of Sylt, Germany). After an experimental period of five weeks (April and May 2015, the main settlement period of S. balanoides), the number of barnacles per mussel was at both sites significantly higher on mussels near the top compared to near the bottom. We conclude that the oyster reef matrix offers a refuge for M. edulis: inside reefs they are not only better protected against predators but also against detrimental barnacle overgrowth. This study shows that alien species can cause beneficial effects for native organisms and should not be generally considered as a risk for the recipient marine ecosystems.

  18. Cypris settlement and dwarf male formation in the barnacle Scalpellum scalpellum

    DEFF Research Database (Denmark)

    Spremberg, U.; Høeg, Jens Thorvald; Buhl-Mortensen, L.

    2012-01-01

    Cypris settlement and metamorphosis into dwarf males were studied in the androdioecious barnacle Scalpellum scalpellum using field collected samples from the North Sea, and experiments with laboratory reared larvae, observed with video. In the field sample, dwarf males were always situated...... surfaces of the adults, or on their hydroid substratum, always developed into hermaphrodites. The numbers settling as males did not differ significantly from those settling as hermaphrodites, suggesting that genetic sex determination may operate in S. scalpellum. The N. Sea sample comprised 52 adult...

  19. Distribution and Size of Barnacle Chelonibia patula Fouling Blue Crab Callinectes amnicola in Southeast Nigeria

    OpenAIRE

    Udoh James Philip; Otoh Aniekan Johnny

    2016-01-01

    The distribution and occurrence of epibionts on the dorsal carapace, ventral carapace and chela of 325 specimens of Callinectes amnicola (De Rocheburne, 1883) (103.4 - 138.7 mm carapace width) from the Qua Iboe (QIRE) and Imo River (IRE) estuaries in southeast Nigeria was determined. The only ectosymbiont observed was cirriped barnacle, Chelonibia patula, mostly of smaller sizes (2.25 mm), infesting only 25-29% of intermoult crabs, more on females and in the Imo River estuary, with an average...

  20. Gregarine Cephaloidophora communis mawrodiadi, 1908 in the barnacle Euraphia rhyzophorae, Oliveira, 1940 from Brazil

    Directory of Open Access Journals (Sweden)

    Lacombe Dyrce

    2002-01-01

    Full Text Available The gregarine Cephaloidophora communis was observed for the first time in Brazil in the barnacles Euraphia rhyzophorae collected in Angra dos Reis, Rio de Janeiro, Brazil, between 1990 and 1996. Histological studies showed growth phases of the parasite in specific parts of the digestive system. The intracellular forms occurred in the vacuoles of the intestinal cells. Syzygy was frequent, and the most common form following syzygy was cylindrical, with a single membrane. The cytoplasm of the gregarines was always irregular, dense, and occasionally presenting a dark stoch area.

  1. Gut fluorescence analysis of barnacle larvae: An approach to quantify the ingested food

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Anil, A.C.

    of Oceanography, Dona Paula, Goa, India A B S T R A C T Gut fluorescence analysis can provide a snapshot of ingested food and has been employed in the feeding studies of various organisms. In this study we standardised the gut fluorescence method utilising... naupliar instars and a pre-settling cyprid instar. The I instar nauplius is non-feeding and moults into II instar within a short interval of time. II to VI instars are phytoplanktivorus. Nauplii obtained from the adult broods of the barnacle Balanus...

  2. Settlement and recruitment of the barnacle Balanus amphitrite from a tropical environment influenced by monsoons

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Anil, A.C.

    and Arambol, the observations were made from June 2006 to May 2007. In addition, at station Dona Paula, weekly observations of settlement and recruitment were also made from June 2005 to May 2007. Two different types of panels (aluminium and acrylic... materials) of size 15x10 cm were used as substratum at stations Dona Paula, MPT and INS-Mandovi. Aluminium and acrylic panels have been used in the past to study the settlement and recruitment of barnacles in the study area and they provide a good...

  3. Setal morphology and cirral setation of thoracican barnacle cirri: adaptations and implications for thoracican evolution

    DEFF Research Database (Denmark)

    Chan, B.K.K.; Garm, A.; Høeg, Jens Thorvald

    2008-01-01

    between cirral setation and feeding mode. The species studied comprise both pedunculate and sessile forms and represent a wide range of marine habitats as well as morphologies, viz., Ibla cumingi, Octolasmis warwickii, Capitulum mitella, Pollicipes polymerus, Tetraclita japonica japonica and Megabalanus...... in the mantle cavity using the setae on their three pairs of maxillipeds. Our results indicate that in thoracican barnacles, adaptations in feeding behaviour are associated with changes in the setation pattern of the cirri. In addition, the setal types and their distribution on the cirri are potential new...

  4. Spatial and temporal patterns of subtidal and intertidal crabs excursions

    Science.gov (United States)

    Silva, A. C. F.; Boaventura, D. M.; Thompson, R. C.; Hawkins, S. J.

    2014-01-01

    Highly mobile predators such as fish and crabs are known to migrate from the subtidal zone to forage in the intertidal zone at high-tide. The extent and variation of these habitat linking movements along the vertical shore gradient have not been examined before for several species simultaneously, hence not accounting for species interactions. Here, the foraging excursions of Carcinus maenas (L.), Necora puber (Linnaeus, 1767) and Cancer pagurus (Linnaeus, 1758) were assessed in a one-year mark-recapture study on two replicated rocky shores in southwest U.K. A comparison between the abundance of individuals present on the shore at high-tide with those present in refuges exposed at low-tide indicated considerable intertidal migration by all species, showing strong linkage between subtidal and intertidal habitats. Estimates of population size based on recapture of marked individuals indicated that an average of ~ 4000 individuals combined for the three crab species, can be present on the shore during one tidal cycle. There was also a high fidelity of individuals and species to particular shore levels. Underlying mechanisms for these spatial patterns such as prey availability and agonistic interactions are discussed. Survival rates were estimated using the Cormack-Jolly-Seber model from multi-recapture analysis and found to be considerably high with a minimum of 30% for all species. Growth rates were found to vary intraspecifically with size and between seasons. Understanding the temporal and spatial variations in predation pressure by crabs on rocky shores is dependent on knowing who, when and how many of these commercially important crab species depend on intertidal foraging. Previous studies have shown that the diet of these species is strongly based on intertidal prey including key species such as limpets; hence intertidal crab migration could be associated with considerable impacts on intertidal assemblages.

  5. Distribution and Size of Barnacle Chelonibia patula Fouling Blue Crab Callinectes amnicola in Southeast Nigeria

    Directory of Open Access Journals (Sweden)

    Udoh James Philip

    2016-09-01

    Full Text Available The distribution and occurrence of epibionts on the dorsal carapace, ventral carapace and chela of 325 specimens of Callinectes amnicola (De Rocheburne, 1883 (103.4 - 138.7 mm carapace width from the Qua Iboe (QIRE and Imo River (IRE estuaries in southeast Nigeria was determined. The only ectosymbiont observed was cirriped barnacle, Chelonibia patula, mostly of smaller sizes (2.25 mm, infesting only 25-29% of intermoult crabs, more on females and in the Imo River estuary, with an average of four barnacles per crab, presupposing low level of epibiont-host interaction. There was no significant difference (P>0.05 in spatial distribution but epibionts were highest in the dry season in low salinity IRE (0.53‰ and in wet season in the medium-salinity QIRE (17.4‰. No public health risk has been reported among crab consumers in the study area. This study highlights epibiont-host interaction in the study area largely unknown for proper management of the fishery.

  6. Fueling incubation : Differential use of body stores in Arctic and temperate-breeding Barnacle Geese (Branta leucopsis)

    NARCIS (Netherlands)

    Eichhorn, Goetz; van der Jeugd, Henk P.; Meijer, Harro A. J.; Drent, Rudolf H.

    We compared the use of body stores in breeding Barnacle Geese (Branta leucopsis) in traditional Arctic colonies in the Barents Sea with that in recently established temperate-zone breeding colonies in the Baltic Sea and North Sea by studying female body-mass loss and use of fat and protein stores

  7. Variation in growth of young and adult size in barnacle geese Branta leucopsis : Evidence for density dependence

    NARCIS (Netherlands)

    Loonen, MJJE; Oosterbeek, K; Drent, RH

    1997-01-01

    A colony of Svalbard Barnacle Geese Branta leucopsis was studied near Ny Alesund, Spitsbergen. Breeding started in 1980 and the colony size followed a sigmoidal curve with little increase in numbers in the period 1992-1995. Over the period 1991-1995 gosling growth declined, mortality during growth

  8. Massive recruitment of the barnacle Semibalanus balanoides in the Clyde Sea (Scotland, UK) in the spring of 2000

    DEFF Research Database (Denmark)

    Hansson, L.J.; Hudson, I.R.; Seddon, R.J.

    2003-01-01

    In April 2000 a massive recruitment of the barnacle Semibalanus balanoides was observed in the Clyde Sea. At one location 700 cyprids l(-1) of this species were recorded. This is similar to3500 times more abundant than previously recorded, and resulted in metamorphosis of some cyprids whilst still...

  9. RESPONSE OF GHOST SHRIMP (NEOTRYPAEA CALIFORNIENSIS) BIOTURBATION TO ORGANIC MATTER ENRICHMENT OF ESTUARINE INTERTIDAL SEDIMENTS

    Science.gov (United States)

    Populations of burrowing shrimp (Neotrypaea californiensis and Upogebia p;ugettensis) are the dominant invertebrate fauna on Pacific estuarine tide flats, occupying >80% of intertidal area in some estuaries. Burrowing shrimp are renowned for their bioturbation of intertidal sedi...

  10. Recolonization of intertidal Zostera marina L. (eelgrass) following experimental shoot removal

    Science.gov (United States)

    The recovery of eelgrass (Zostera marina) from physical disturbances is understudied and no attention has been given to the likely differences in damage recovery rates between the continuous lower intertidal perennial meadows and higher intertidal eelgrass patches. In the present...

  11. Production and consumption of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in a diatom dominated intertidal sediment

    NARCIS (Netherlands)

    Van Bergeijk, S.A.; Schönefeldt, K.; Stal, L.J.; Huisman, J.

    2002-01-01

    Intertidal sediments usually contain a high amount of dimethylsulfoniopropionate (DMSP) and therefore represent environments with a potentially high emission of dimethylsulfide (DMS). However, knowledge on production and release of DMSP in intertidal sediments is limited. Here, we present data on

  12. The ecology of intertidal oyster reefs of the South Atlantic Coast: A community profile

    Science.gov (United States)

    Bahr, Leonard M.; Lanier, William P.

    1981-01-01

    The functional role of the intertidal oyster reef community in the southeastern Atlantic coastal zone is described. This description is based on a compilation of published data, as well as some unpublished information presented as hypotheses. The profile is organized in a hierarchical manner, such that relevant details of reef oyster biology (autecology) are presented, followed by a description of the reef community level of organization. Then the reef community is described as a subsystem of the coastal marsh-ecosystem (synecoloqy). This information is also synthesized in a series of nested conceptual models of oyster reefs at the regional level, the drainage basin level, and the individual reef level. The final chapter includes a summary overview and a section on management implications and guidelines. Intertidal oyster reefs are relatively persistent features of the salt marsh estuarine ecosystem in the southeastern Atlantic coastal zone. The average areal extent of the oyster reef subsystem in this larger ecosystem is relatively small (about 0.05%). This proportion does not reflect, however, the functional importance of the reef subsystem in stablizing the marsh, providing food for estuarine consumers, mineralizing organic matter, and providing firm substrates in this otherwise soft environment.

  13. Patterns of Spatial Variation of Assemblages Associated with Intertidal Rocky Shores: A Global Perspective

    Science.gov (United States)

    Cruz-Motta, Juan José; Miloslavich, Patricia; Palomo, Gabriela; Iken, Katrin; Konar, Brenda; Pohle, Gerhard; Trott, Tom; Benedetti-Cecchi, Lisandro; Herrera, César; Hernández, Alejandra; Sardi, Adriana; Bueno, Andrea; Castillo, Julio; Klein, Eduardo; Guerra-Castro, Edlin; Gobin, Judith; Gómez, Diana Isabel; Riosmena-Rodríguez, Rafael; Mead, Angela; Bigatti, Gregorio; Knowlton, Ann; Shirayama, Yoshihisa

    2010-01-01

    Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs); however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample) was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST) and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index) were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution), we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses. PMID:21179546

  14. Patterns of spatial variation of assemblages associated with intertidal rocky shores: a global perspective.

    Directory of Open Access Journals (Sweden)

    Juan José Cruz-Motta

    2010-12-01

    Full Text Available Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org. There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs; however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution, we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses.

  15. Microplastic-associated Bacterial Assemblages in the Intertidal Zone

    Science.gov (United States)

    Jiang, P.; Zhao, S.; Zhu, L.; Li, D.

    2017-12-01

    Plastic debris is posing a planetary-scale threat. As a zone where terrestrial and marine ecosystems interactions occur, the accumulation of plastic marine debris (PMD) in intertidal environments has been well documented. But the information of plastic-associated microbial community (the "Plastisphere") in the intertidal zone is scanty. Utilizing the high-throughput sequencing, we profiled the bacterial communities attached to microplastic samples from the intertidal locations around Yangtze estuary. The structure and composition of Plastisphere communities in current study varied significantly with geographical stations. The taxonomic composition on microplastic samples implied their sedimental and aquatic origins. Some members of hydrocarbon degrading microorganisms and potential pathogens were detected on microplastic. Overall, our findings fuel the evidence for the occurrence of diverse microbial assemblages on PMD and improving our understanding of Plastisphere ecology, which could support the management action and policy change related to PMD.

  16. A High-Level Fungal Diversity in the Intertidal Sediment of Chinese Seas Presents the Spatial Variation of Community Composition.

    Science.gov (United States)

    Li, Wei; Wang, Mengmeng; Bian, Xiaomeng; Guo, Jiajia; Cai, Lei

    2016-01-01

    The intertidal region is one of the most dynamic environments in the biosphere, which potentially supports vast biodiversity. Fungi have been found to play important roles in marine ecosystems, e.g., as parasites or symbionts of plants and animals, and as decomposers of organic materials. The fungal diversity in intertidal region, however, remains poorly understood. In this study, sediment samples from various intertidal habitats of Chinese seas were collected and investigated for determination of fungal community and spatial distribution. Through ribosomal RNA internal transcribed spacer-2 (ITS2) metabarcoding, a high-level fungal diversity was revealed, as represented by 6,013 OTUs that spanned six phyla, 23 classes, 84 orders and 526 genera. The presence of typical decomposers (e.g., Corollospora in Ascomycota and Lepiota in Basidiomycota) and pathogens (e.g., Olpidium in Chytriomycota, Actinomucor in Zygomycota and unidentified Rozellomycota spp.), and even mycorrhizal fungi (e.g., Glomus in Glomeromycota) indicated a complicated origin of intertidal fungi. Interestingly, a small proportion of sequences were classified to obligate marine fungi (e.g., Corollospora, Lignincola, Remispora, Sigmoidea ). Our data also showed that the East China Sea significantly differed from other regions in terms of species richness and community composition, indicating a profound effect of the huge discharge of the Yangtze River. No significant difference in fungal communities was detected, however, among habitat types (i.e., aquaculture, dock, plant, river mouth and tourism). These observations raise further questions on adaptation of these members to environments and the ecological functions they probably perform.

  17. Numerical simulations of barnacle larval dispersion coupled with field observations on larval abundance, settlement and recruitment in a tropical monsoon influenced coastal marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Samiksha S.V.; George, G.; Aboobacker V.M.; Vethamony, P.; Anil, A.C.

    Observations were carried out to monitor the larval abundance, settlement and recruitment of barnacles on a regular basis for a period of two years. The results were then compared with the numerical modelling studies carried out along the west coast...

  18. Sustainable Seas Student Intertidal Monitoring Project, Duxbury Reef, Bolinas, CA

    Science.gov (United States)

    Soave, K.; Dean, A.; Prescutti, K.; Ball, O.; Chang, E.; Darakananda, K.; Jessup, K.; Poutian, J.; Schwalbe, H.; Storm, E.

    2008-12-01

    The Sustainable Seas Student Monitoring Project at the Branson School in Ross, CA has monitored Duxbury Reef in Bolinas, CA since 1999, in cooperation with the Farallones Marine Sanctuary Association and the Gulf of Farallones National Marine Sanctuary. Goals of the project include: 1) To monitor the rocky intertidal habitat and develop a baseline database of invertebrates and algal density and abundance; 2) To contribute to the conservation of the rocky intertidal habitat through education of students and visitors about intertidal species and requirements for maintaining a healthy, diverse intertidal ecosystem; 3) To increase stewardship in the Gulf of the Farallones National Marine Sanctuary; and 4) To contribute abundance and population data on key algae and invertebrate species to the national database, LiMPETS (Long Term Monitoring Program and Experiential Training for Students). Student volunteers complete an intensive training course on the natural history of intertidal invertebrates and algae, identification of key species, rocky intertidal ecology, interpretation and monitoring techniques, and history of the sanctuary. Students identify and count key invertebrate and algae species along two permanent transects (A and B), and using randomly determined points within a permanent 100 m2 area, three times per year (fall, winter, and late spring). Using the data collected since 2004, we will analyze the population densities of aggregating anemones, Anthopleura elegantissima, for seasonal abundance variations as well as long-term population trends. We will also follow the seasonal and long-term population fluctuations of red algal turf, Endocladia muricata and Gelidium coulteri, and black turban snails, Tegula funebralis. Comparing populations of turf algae and the herbivorous black turban snails gathered before and after the November 7, 2007 San Francisco Bay oil spill shows very little impact on the Duxbury Reef intertidal inhabitants. Future analyses will

  19. Darwin taxonomist: Barnacles and shell burrowing barnacles Darwin taxónomo: cirrípedos y cirrípedos perforadores de conchas

    Directory of Open Access Journals (Sweden)

    JUAN CARLOS CASTILLA

    2009-12-01

    Full Text Available This bibliographic review revisits circumstances in which the wharf, shell burrowing barnacle, Cryptophialus minutus, was first collected by Charles Darwin in southern Chile, in 1836. Further, explores how its collection marked Darwin's taxonomical interest in Cirripedia. A short review analyzes the initial number of extant species of Cirripedia, as described by Darwin and the present situation, with emphasis on recent collections of C. minutus in the southern tip of South America.Esta revisión bibliográfica describe las circunstancias en el que el cirrípedo enano, Crypophialus minutus, perforador de conchas, fue recolectado por Charles Darwin en el sur de Chile, en 1836. Además, cómo esta recolección marcó el interés taxonómico de Darwin en Cirripedia. Se presenta una revisión resumida sobre el número inicial de especies vivas de Cirripedia, como fueron descritas por Darwin, y la situación actual, con énfasis en recolecciones recientes de C. minutus en el cono sur de Suramérica.

  20. Molecular phylogeny and character evolution of the chthamaloid barnacles (Cirripedia:Thoracica)

    DEFF Research Database (Denmark)

    Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, Keith A.

    2012-01-01

    surrounded by whorls of small imbricating plates; but this hypothesis has never been subjected to a rigorous phylogenetic test. Here we used multilocus sequence data and extensive taxon sampling to build a comprehensive phylogeny of the Chthamaloidea as a basis for understanding their morphological evolution......The Chthamaloidea (Balanomorpha) present the most plesiomorphic characters in shell plates and cirri, mouthparts, and oral cone within the acorn barnacles (Thoracica: Sessilia). Due to their importance in understanding both the origin and diversification of the Balanomorpha, the evolution...... of the Chthamaloidea has been debated since Darwin's seminal monographs. Theories of morphological and ontogenetic evolution suggest that the group could have evolved multiple times from pedunculated relatives and that shell plate number diminished gradually (8¿6¿4) from an ancestral state with eight wall plates...

  1. Biodiversity and Biogeography of Chthamalid Barnacles from the North-Eastern Pacific (Crustacea Cirripedia.

    Directory of Open Access Journals (Sweden)

    Benny K K Chan

    Full Text Available The biogeography and ecology of the species of Chthamalus present on the west coast of America are described, using data from 51 localities from Alaska to Panama, together with their zonation on the shore with respect to that of other barnacles. The species present were C. dalli, Pilsbry 1916, C. fissus, Darwin, 1854, C. anisopoma Pilsbry 1916 and four species in the C. panamensis complex. The latter are C. panamensis Pilsbry, 1916, C. hedgecocki, Pitombo & Burton, 2007, C. alani nom. nov. (formerly C. southwardorum Pitombo & Burton, 2007 and C. newmani sp. nov.. These four species were initially separated by enzyme electrophoresis. They could only be partially separated by DNA bar coding but may be separated using morphological characters.

  2. Evidence for the Involvement of p38 MAPK Activation in Barnacle Larval Settlement

    KAUST Repository

    He, Li-Sheng

    2012-10-24

    The barnacle Balanus ( = Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts.

  3. Evidence for the Involvement of p38 MAPK Activation in Barnacle Larval Settlement

    KAUST Repository

    He, Li-Sheng; Xu, Ying; Matsumura, Kiyotaka; Zhang, Yu; Zhang, Gen; Qi, Shu-Hua; Qian, Pei-Yuan

    2012-01-01

    The barnacle Balanus ( = Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts.

  4. Photoacclimatory Responses of Zostera marina in the Intertidal and Subtidal Zones.

    Science.gov (United States)

    Park, Sang Rul; Kim, Sangil; Kim, Young Kyun; Kang, Chang-Keun; Lee, Kun-Seop

    2016-01-01

    Photoacclimatory responses of the seagrass Zostera marina in the intertidal and subtidal zones were investigated by measuring chlorophyll a fluorescence parameters, photosynthetic pigments, leaf δ13C values, and shoot morphology in two bay systems. Intertidal plants had higher carotenoid concentrations than subtidal plants to avoid photodamage under excess light conditions during the day. The maximum relative electron transport rate (rETRmax) and minimum saturation irradiance (Ek) of the intertidal plants were higher than those of the subtidal plants, whereas photosynthetic efficiency (α) and maximum quantum yield (Fv/Fm) were higher in subtidal plants. The intertidal plants also had significantly greater Stern-Volmer non-photochemical quenching (NPQ) than that of the subtidal plants. These results suggest that the subtidal plants photoacclimated to use limited light more efficiently, and the intertidal plants exhibited photosynthetic responses to minimize photodamage at excess irradiance. The δ13C values of leaf tissues were more negative in the intertidal plants than those in the subtidal plants, suggesting that the intertidal plants used atmospheric or dissolved CO2 for photosynthesis during emersion. Effective quantum yield (ΔF/Fm´) in the intertidal plants decreased more slowly after emersion than that in the subtidal plants, indicating higher desiccation tolerance of the intertidal plants. The intertidal plants also recovered more rapidly from desiccation damage than the subtidal plants, suggesting photosynthetic adaptation to desiccation stress. The photosynthetic plasticity of Z. marina in response to variable environmental conditions most likely allows this species to occur in the intertidal and subtidal zones.

  5. Radionuclides in intertidal sands and sediments from Morecambe Bay to the Dee estuary

    International Nuclear Information System (INIS)

    Carpenter, R.C.; Burton, P.J.; Strange, L.P.; Pratley, F.W.

    1991-05-01

    Surface and core samples of intertidal sediments have been collected from the coastline from Morecambe Bay to the Dee Estuary. The sampling took place between October 1987 and July 1989. Caesium-137 was determined by high resolution gamma spectrometry and plutonium isotopes and americium-241 were determined by alpha spectrometry following radiochemical separations. Samples were also sieved to obtain a particle size distribution of the deposits. A wide range of radionuclide activities have been determined depending on the distance from Sellafield and, more importantly, the proportion of clay plus silt ( 239+240 Pu and 241 Am activity discharged by Sellafield up to the end of 1988. The measured activities generally represent a small fraction of the Generalised Derived Limits (GDL's) for marine sediments. (author)

  6. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng; Wang, Yong; Lee, On On; Tian, Renmao; Cao, Huiluo; Gao, Zhaoming; Li, Yongxin; Yu, Li; Xu, Ying; Qian, Pei-Yuan

    2013-01-01

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  7. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng

    2013-11-11

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  8. Foraminiferal assemblages along the intertidal zone of Itapanhaú River, Bertioga (Brazil)

    Science.gov (United States)

    Passos, Camila Cunha; Kukimodo, Isabela; Semensatto, Décio

    2017-11-01

    Foraminifera found in intertidal zones have been successfully used in studies examining relative sea level monitoring around the world. For this purpose, it is necessary to establish the typical foraminiferal assemblages of different salinity regimes and sediment sub aerial exposition. In the present work we collected 27 sediment samples from 5 transversal transects in the mangroves of the Itapanhaú River (Bertioga, SP, Brazil). Transects were distributed along salinity and altitudinal gradients in order to study the community structure of recent foraminifera in terms of diversity and species composition. We identified 35 species and described 5 groups of species in different environmental settings, from downstream to upstream and from margin to landward in the mangrove forest, associated with salinity regime and sediment proportional exposure time. These variables seem to primarily control species distribution and community structure in the intertidal zone, although dissolution of calcareous taxa cannot be ruled out. The first group is dominated by Ammonia spp. and Elphidium spp., colonizes the mouth of the river on an unvegetated tidal flat in the lowest portion of the intertidal zone, under a polyhaline regime. This group exhibits the smallest sub aerial exposition (19,3%) as well as comparatively high species diversity. The second group is formed by a sample dominated by Trochammina inflata and Arenoparrella mexicana, obtained in a polyhaline area on the margin of the mangrove. The third group is dominated by Miliammina fusca and Ammotium spp., and colonizes mesohaline mangrove forests, with proportional exposure time of between 50 and 75%, and high species diversity. The fourth group comprises communities dominated by M. fusca and T. inflata, and colonizes the intermediate level in the interior of the mangrove forest, exhibiting high species diversity. The fifth group comprises communities broadly dominated by M. fusca, colonizing oligohaline margins and the

  9. Coastal Upwelling Drives Intertidal Assemblage Structure and Trophic Ecology.

    Science.gov (United States)

    Reddin, Carl J; Docmac, Felipe; O'Connor, Nessa E; Bothwell, John H; Harrod, Chris

    2015-01-01

    Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecology across eighteen shores varying in their proximity to two coastal upwelling centres, in a hierarchical sampling design (spatial scales of >1 and >10 km). The influence of coastal upwelling on intertidal communities was confirmed by the stable isotope values (δ13C and δ15N) of consumers, including a dominant suspension feeder, grazers, and their putative resources of POM, epilithic biofilm, and macroalgae. We highlight the utility of muscle δ15N from the suspension feeding mussel, Perumytilus purpuratus, as a proxy for upwelling, supported by satellite data and previous studies. Where possible, we used corrections for broader-scale trends, spatial autocorrelation, ontogenetic dietary shifts and spatial baseline isotopic variation prior to analysis. Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands. Coastal topography also separated differences in consumer resource use. This suggested that coastal upwelling, itself driven by coastline topography, influences intertidal communities by advecting nearshore phytoplankton populations offshore and cooling coastal water temperatures. We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

  10. Spatial and temporal variability in recruitment of intertidal mussels ...

    African Journals Online (AJOL)

    Intensity of intertidal mussel recruitment was compared across a range of different spatial and temporal scales around the coast of southern Africa between June 1995 and October 1996. Comparison of the east and west coasts revealed significantly higher recruit densities on the west coast, corresponding to larger adult ...

  11. Intertidal mangrove boundary zones as nursery grounds for the mud ...

    African Journals Online (AJOL)

    This study investigated the tidal, diurnal and seasonal occurrence of juvenile crabs in three habitats (intertidal-flat boundary zones, inside the mangroves, and in channels) in small creeks (Mida, Kilifi and Mtwapa) and Gazi Bay, on the coast of Kenya. Sampling was done with scoop nets and seining at receding tides and via ...

  12. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-01-01

    Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes. PMID:26883983

  13. Laboratory experiments on the infaunal activity of intertidal nematodes

    NARCIS (Netherlands)

    Steyaert, M.; Moodley, L.; Vanaverbeke, J.; Vandewiele, S.L.; Vincx, M.

    2005-01-01

    The impact of oxygen on the vertical distribution of an intertidal nematode community was investigated in a manipulation experiment with sediments collected from the Oosterschelde (The Netherlands). The vertical distribution of nematodes was examined in response to sediment inversion in perspex

  14. Alkalinity production in intertidal sands intensified by lugworm bioirrigation

    NARCIS (Netherlands)

    Rao, A.M.F.; Malkin, S.Y.; Montserrat, F; Meysman, F.J.R.

    2014-01-01

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete

  15. Estuarine Ecosystem Engineering : Biogeomorphology in the estuarine intertidal

    NARCIS (Netherlands)

    Montserrat Trotsenburg, F.

    2011-01-01

    The aim of this thesis was to investigate how (macro)benthic organisms interact with the ecological functioning, erodibility and small- to medium-scale morphodynamics of estuarine intertidal sediment by modulating its composition and/or properties. In these interactions, scale is of great importance

  16. Intertidal sediments and benthic animals of Roebuck Bay, Western Australia

    NARCIS (Netherlands)

    Pepping, M.; Piersma, T.; Pearson, G.; Lavaleye, M.

    1999-01-01

    Roebuck Bay near Broome (NW Australia) is with itsextensive tidal flats one of the foremost internationallyimportant sites for shorebirds in the Asia-Pacificflyway system. It is home to 150,000 shorebirds (or‘waders’) in the nonbreeding season, which suggeststhat the intertidal flats of the bay have

  17. Mussel beds are biological power stations on intertidal flats

    NARCIS (Netherlands)

    Engel, Friederike G.; Alegria, Javier; Andriana, Rosyta; Donadi, Serena; Gusmao, Joao B.; van Leeuwe, Maria A.; Matthiessen, Birte; Eriksson, Britas Klemens

    2017-01-01

    Intertidal flats are highly productive areas that support large numbers of invertebrates, fish, and birds. Benthic diatoms are essential for the function of tidal flats. They fuel the benthic food web by forming a thin photosynthesizing compartment in the top-layer of the sediment that stretches

  18. Effect of Mudflat Trampling on Activity of Intertidal Crabs

    Science.gov (United States)

    Kim, Tae Won; Kim, Sanha; Lee, Jung-Ah

    2018-03-01

    Many people visit intertidal mudflats to collect bait and seafood, or for eco-tourism and recreation, and as a consequence trample on the mudflats frequently. Trampling would not be life threatening to most animals in the intertidal flats as they have evolved hiding behavior to escape predation. However, what is the effect of trampling on the behavior of intertidal animals? In this study, the effect of mudflat trampling on the activity of crabs (e.g. fiddler crabs, sentinel crabs) living on the mudflat was explored. The number of crabs active on the mudflat surface in experimental plots (1.5 × 1.5 m2) before and after (10 min. and 30 min.) trampling of three different intensities (Heavy trampling = 60 steps; Moderate trampling = 20 steps; and No trampling) was compared in two different mudflat systems. After trampling, the number of crabs active on the surface decreased and was significantly lower than that of control plots. The more intensively trampled the mudflat was, the fewer crabs were active on the mudflat surface. Surprisingly, the number of active crabs did not recover even 30 min. after trampling. The results clearly support the hypothesis that trampling can severely interfere with the behavior of crabs living on intertidal mudflats.

  19. Ecosystem Carbon Stocks of Intertidal Wetlands in Singapore

    Science.gov (United States)

    Phang, V. X. H.; Friess, D.; Chou, L. M.

    2014-12-01

    Mangrove forests and seagrass meadows provide numerous ecosystem services, with huge recent interest in their carbon sequestration and storage value. Mangrove forests and seagrass meadows as well as mudflats and sandbars form a continuum of intertidal wetlands, but studies that consider these spatially-linked habitats as a whole are limited. This paper presents the results of a field-based and remote sensing carbon stock assessment, including the first study of the ecosystem carbon stocks of these adjacent habitats in the tropics. Aboveground, belowground and soil organic carbon pools were quantified at Chek Jawa, an intertidal wetland in Singapore. Total ecosystem carbon stocks averaged 499 Mg C ha-1 in the mangrove forest and 140 Mg C ha-1 in the seagrass meadow. Soil organic carbon dominated the total storage in both habitats. In the adjacent mudflats and sandbars, soil organic carbon averaged 143 and 124 Mg C ha-1 respectively. High amount of carbon stored in soil demonstrate the role of intertidal wetlands in sequestering large amount of carbon in sediments accumulated over millennia. High-resolution remote sensing imagery was used to create spatial models that upscaled field-based carbon measurements to the national scale. Field-based data and spatial modeling of ecosystem carbon stocks to the entire island through remote sensing provides a large-scale and holistic carbon stock value, important for the understanding and management of these threatened intertidal ecosystems.

  20. Disturbance-mediated facilitation by an intertidal ecosystem engineer.

    Science.gov (United States)

    Wright, Jeffrey T; Gribben, Paul E

    2017-09-01

    Ecosystem engineers facilitate communities by providing a structural habitat that reduces abiotic stress or predation pressure for associated species. However, disturbance may damage or move the engineer to a more stressful environment, possibly increasing the importance of facilitation for associated communities. In this study, we determined how disturbance to intertidal boulders (i.e., flipping) and the subsequent movement of a structural ecosystem engineer, the tube-forming serpulid worm Galeolaria caespitosa, from the bottom (natural state, low abiotic stress) to the top (disturbed state, high abiotic stress) surface of boulders influenced the importance of facilitation for intertidal communities across two intertidal zones. Theory predicts stronger relative facilitation should occur in the harsher environments of the top of boulders and the high intertidal zone. To test this prediction, we experimentally positioned boulders with the serpulids either face up or face down for 12 months in low and high zones in an intertidal boulder field. There were very different communities associated with the different boulders and serpulids had the strongest facilitative effects on the more stressful top surface of boulders with approximately double the species richness compared to boulders lacking serpulids. Moreover, within the serpulid matrix itself there was also approximately double the species richness (both zones) and abundance (high zone only) of small invertebrates on the top of boulders compared to the bottom. The high relative facilitation on the top of boulders reflected a large reduction in temperature by the serpulid matrix on that surface (up to 10°C) highlighting a key role for modification of the abiotic environment in determining the community-wide facilitation. This study has demonstrated that disturbance and subsequent movement of an ecosystem engineer to a more stressful environment increased the importance of facilitation and allowed species to

  1. Effects of food availability on growth and reproduction of the deep-sea pedunculate barnacle Heteralepas canci

    Science.gov (United States)

    Yasuda, Natsumi; Miyamoto, Norio; Fujiwara, Yoshihiro; Yamamoto, Tomoko; Yusa, Yoichi

    2016-02-01

    Sessile animals living on continental shelves or slopes may adjust their growth and reproduction according to temporally and spatially variable food availability, but little information is available on these animals to date. We collected the pedunculate barnacle Heteralepas canci on a continental slope at a depth of 229 m off Cape Nomamisaki in southern Japan. We developed a rearing method for the barnacles and studied their growth and reproduction at different food levels in the laboratory. A total of 136 individual H. canci were fed with Artemia salina larvae and brewer's yeast at three different food levels for 100 days. Both the growth and the ovary development were delayed when food availability was low, whereas the survival rate was lower at the high food level. In addition, an individual survived under complete starvation for 167 days. We concluded that H. canci has plastic life history traits that are adaptive for variable food availability.

  2. Proportioning of light weight concrete

    DEFF Research Database (Denmark)

    Palmus, Lars

    1996-01-01

    Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory......Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory...

  3. Microsatellite loci discovery from next-generation sequencing data and loci characterization in the epizoic barnacle Chelonibia testudinaria (Linnaeus, 1758)

    OpenAIRE

    Ewers-Saucedo, Christine; Zardus, John D.; Wares, John P.

    2016-01-01

    Microsatellite markers remain an important tool for ecological and evolutionary research, but are unavailable for many non-model organisms. One such organism with rare ecological and evolutionary features is the epizoic barnacle Chelonibia testudinaria (Linnaeus, 1758). Chelonibia testudinaria appears to be a host generalist, and has an unusual sexual system, androdioecy. Genetic studies on host specificity and mating behavior are impeded by the lack of fine-scale, highly variable markers, su...

  4. Stable isotopes in barnacles as a tool to understand green sea turtle (Chelonia mydas) regional movement patterns

    Science.gov (United States)

    Detjen, M.; Sterling, E.; Gómez, A.

    2015-12-01

    Sea turtles are migratory animals that travel long distances between their feeding and breeding grounds. Traditional methods for researching sea turtle migratory behavior have important disadvantages, and the development of alternatives would enhance our ability to monitor and manage these globally endangered species. Here we report on the isotope signatures in green sea-turtle (Chelonia mydas) barnacles (Platylepas sp.) and discuss their potential relevance as tools with which to study green sea turtle migration and habitat use patterns. We analyzed oxygen (δ18O) and carbon (δ13C) isotope ratios in barnacle calcite layers from specimens collected from green turtles captured at the Palmyra Atoll National Wildlife Refuge (PANWR) in the central Pacific. Carbon isotopes were not informative in this study. However, the oxygen isotope results suggest likely regional movement patterns when mapped onto a predictive oxygen isotope map of the Pacific. Barnacle proxies could therefore complement other methods in understanding regional movement patterns, informing more effective conservation policy that takes into account connectivity between populations.

  5. Effects of Toxic Leachate from Commercial Plastics on Larval Survival and Settlement of the Barnacle Amphibalanus amphitrite.

    Science.gov (United States)

    Li, Heng-Xiang; Getzinger, Gordon J; Ferguson, P Lee; Orihuela, Beatriz; Zhu, Mei; Rittschof, Daniel

    2016-01-19

    Plastic pollution represents a major and growing global problem. It is well-known that plastics are a source of chemical contaminants to the aquatic environment and provide novel habitats for marine organisms. The present study quantified the impacts of plastic leachates from the seven categories of recyclable plastics on larval survival and settlement of barnacle Amphibalanus (=Balanus) amphitrite. Leachates from plastics significantly increased barnacle nauplii mortality at the highest tested concentrations (0.10 and 0.50 m(2)/L). Hydrophobicity (measured as surface energy) was positively correlated with mortality indicating that plastic surface chemistry may be an important factor in the effects of plastics on sessile organisms. Plastic leachates significantly inhibited barnacle cyprids settlement on glass at all tested concentrations. Settlement on plastic surfaces was significantly inhibited after 24 and 48 h, but settlement was not significantly inhibited compared to the controls for some plastics after 72-96 h. In 24 h exposure to seawater, we found larval toxicity and inhibition of settlement with all seven categories of recyclable commercial plastics. Chemical analysis revealed a complex mixture of substances released in plastic leachates. Leaching of toxic compounds from all plastics should be considered when assessing the risks of plastic pollution.

  6. Proportional Symbol Mapping in R

    Directory of Open Access Journals (Sweden)

    Susumu Tanimura

    2006-01-01

    Full Text Available Visualization of spatial data on a map aids not only in data exploration but also in communication to impart spatial conception or ideas to others. Although recent carto-graphic functions in R are rapidly becoming richer, proportional symbol mapping, which is one of the common mapping approaches, has not been packaged thus far. Based on the theories of proportional symbol mapping developed in cartography, the authors developed some functions for proportional symbol mapping using R, including mathematical and perceptual scaling. An example of these functions demonstrated the new expressive power and options available in R, particularly for the visualization of conceptual point data.

  7. Optical fusions and proportional syntheses

    Science.gov (United States)

    Albert-Vanel, Michel

    2002-06-01

    A tragic error is being made in the literature concerning matters of color when dealing with optical fusions. They are still considered to be of additive nature, whereas experience shows us somewhat different results. The goal of this presentation is to show that fusions are, in fact, of 'proportional' nature, tending to be additive or subtractive, depending on each individual case. Using the pointillist paintings done in the manner of Seurat, or the spinning discs experiment could highlight this intermediate sector of the proportional. So, let us try to examine more closely what occurs in fact, by reviewing additive, subtractive and proportional syntheses.

  8. Proportional counter end effects eliminator

    International Nuclear Information System (INIS)

    Meekins, J.F.

    1976-01-01

    An improved gas-filled proportional counter which includes a resistor network connected between the anode and cathode at the ends of the counter in order to eliminate ''end effects'' is described. 3 Claims, 2 Drawing Figures

  9. Electronics for proportional drift tubes

    International Nuclear Information System (INIS)

    Fremont, G.; Friend, B.; Mess, K.H.; Schmidt-Parzefall, W.; Tarle, J.C.; Verweij, H.; CERN-Hamburg-Amsterdam-Rome-Moscow Collaboration); Geske, K.; Riege, H.; Schuett, J.; CERN-Hamburg-Amsterdam-Rome-Moscow Collaboration); Semenov, Y.; CERN-Hamburg-Amsterdam-Rome-Moscow Collaboration)

    1980-01-01

    An electronic system for the read-out of a large number of proportional drift tubes (16,000) has been designed. This system measures deposited charge and drift-time of the charge of a particle traversing a proportional drift tube. A second event can be accepted during the read-out of the system. Up to 40 typical events can be collected and buffered before a data transfer to a computer is necessary. (orig.)

  10. Analogical proportions: another logical view

    Science.gov (United States)

    Prade, Henri; Richard, Gilles

    This paper investigates the logical formalization of a restricted form of analogical reasoning based on analogical proportions, i.e. statements of the form a is to b as c is to d. Starting from a naive set theoretic interpretation, we highlight the existence of two noticeable companion proportions: one states that a is to b the converse of what c is to d (reverse analogy), while the other called paralogical proportion expresses that what a and b have in common, c and d have it also. We identify the characteristic postulates of the three types of proportions and examine their consequences from an abstract viewpoint. We further study the properties of the set theoretic interpretation and of the Boolean logic interpretation, and we provide another light on the understanding of the role of permutations in the modeling of the three types of proportions. Finally, we address the use of these proportions as a basis for inference in a propositional setting, and relate it to more general schemes of analogical reasoning. The differences between analogy, reverse-analogy, and paralogy is still emphasized in a three-valued setting, which is also briefly presented.

  11. Analysis of aquaporins from the euryhaline barnacle Balanus improvisus reveals differential expression in response to changes in salinity.

    Directory of Open Access Journals (Sweden)

    Ulrika Lind

    Full Text Available Barnacles are sessile macro-invertebrates, found along rocky shores in coastal areas worldwide. The euryhaline bay barnacle Balanus improvisus (Darwin, 1854 (= Amphibalanus improvisus can tolerate a wide range of salinities, but the molecular mechanisms underlying the osmoregulatory capacity of this truly brackish species are not well understood. Aquaporins are pore-forming integral membrane proteins that facilitate transport of water, small solutes and ions through cellular membranes, and that have been shown to be important for osmoregulation in many organisms. The knowledge of the function of aquaporins in crustaceans is, however, limited and nothing is known about them in barnacles. We here present the repertoire of aquaporins from a thecostracan crustacean, the barnacle B. improvisus, based on genome and transcriptome sequencing. Our analyses reveal that B. improvisus contains eight genes for aquaporins. Phylogenetic analysis showed that they represented members of the classical water aquaporins (Aqp1, Aqp2, the aquaglyceroporins (Glp1, Glp2, the unorthodox aquaporin (Aqp12 and the arthropod-specific big brain aquaporin (Bib. Interestingly, we also found two big brain-like proteins (BibL1 and BibL2 constituting a new group of aquaporins not yet described in arthropods. In addition, we found that the two water-specific aquaporins were expressed as C-terminal splice variants. Heterologous expression of some of the aquaporins followed by functional characterization showed that Aqp1 transported water and Glp2 water and glycerol, agreeing with the predictions of substrate specificity based on 3D modeling and phylogeny. To investigate a possible role for the B. improvisus aquaporins in osmoregulation, mRNA expression changes in adult barnacles were analysed after long-term acclimation to different salinities. The most pronounced expression difference was seen for AQP1 with a substantial (>100-fold decrease in the mantle tissue in low salinity (3

  12. Marine biology, intertidal ecology, and a new place for biology.

    Science.gov (United States)

    Benson, Keith R

    2015-01-01

    At the present time, there is considerable interest for the physical setting of science, that is, its actual 'place' of practice. Among historians of biology, place has been considered to be a crucial component for the study of ecology. Other historians have noted the 'built' environments (laboratories) for the study of biology along the seashore, even referring to these places in terms more applicable to vacation sites. In this paper, I examine the place of intertidal ecology investigations, both in terms of the physical space and the built space. Part of the examination will investigate the aesthetic aspect of the Pacific Coast, part will evaluate the unique character of the intertidal zone, and part will consider the construction of natural laboratories and built laboratories as characteristic places for biology.

  13. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    The article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area...... spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...... macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin...

  14. Impacts and effects of ocean warming on intertidal rocky habitats

    OpenAIRE

    Hawkins, Stephen J.; Evans, A J; Firth, L B; Genner, Martin J; Herbert, R J H; Adams, L C; Moore, P J; Mieszkowska, N; Thompson, R.C.; Burrows, M.T.; Fenberg, P.B.

    2016-01-01

    Intertidal rocky habitats comprise over 50% of the shorelines of the world, supporting a diversity of marine life and providing extensive ecosystem services worth in the region of US$ 5-10 trillion per year. • They are valuable indicators of the impacts of climate change on the wider marine environment and ecosystems. • Changes in species distributions, abundance and phenology have already been observed around the world in response to recent rapid climate change. • Species-level responses w...

  15. Artificial light at night alters trophic interactions of intertidal invertebrates.

    Science.gov (United States)

    Underwood, Charlotte N; Davies, Thomas W; Queirós, Ana M

    2017-07-01

    Despite being globally widespread in coastal regions, the impacts of light pollution on intertidal ecosystems has received little attention. Intertidal species exhibit many night-time-dependent ecological strategies, including feeding, reproduction, orientation and predator avoidance, which are likely negatively affected by shifting light regimes, as has been observed in terrestrial and aquatic taxa. Coastal lighting may shape intertidal communities through its influence on the nocturnal foraging activity of dogwhelks (Nucella lapillus), a widespread predatory mollusc that structures biodiversity in temperate rocky shores. In the laboratory, we investigated whether the basal and foraging activity of this predator was affected by exposure to night-time lighting both in the presence and absence of olfactory predator cues (Carcinus maenas, common shore crab). Assessments of dogwhelks' behavioural responses to night-time white LED lighting were performed on individuals that had been acclimated to night-time white LED lighting conditions for 16 days and individuals that had not previously been exposed to artificial light at night. Dogwhelks acclimated to night-time lighting exhibited natural refuge-seeking behaviour less often compared to control animals, but were more likely to respond to and handle prey irrespective of whether olfactory predator cues were present. These responses suggest night-time lighting likely increased the energetic demand of dogwhelks through stress, encouraging foraging whenever food was available, regardless of potential danger. Contrastingly, whelks not acclimated under night-time lighting were more likely to respond to the presence of prey under artificial light at night when olfactory predator cues were present, indicating an opportunistic shift towards the use of visual instead of olfactory cues in risk evaluation. These results demonstrate that artificial night-time lighting influences the behaviour of intertidal fauna such that the

  16. Intertidal population genetic dynamics at a microgeographic seascape scale.

    Science.gov (United States)

    Hu, Zi-Min

    2013-06-01

    The intertidal community is among the most physically harsh niches on earth, with highly heterogeneous environmental and biological factors that impose strong habitat selection on population abundance, genetic connectivity and ecological adaptation of organisms in nature. However, most genetic studies to date have concentrated on the influence of basin-wide or regional marine environments (e.g. habitat discontinuities, oceanic currents and fronts, and geographic barriers) on spatiotemporal distribution and composition of intertidal invertebrates having planktonic stages or long-distance dispersal capability. Little is known about sessile marine organisms (e.g. seaweeds) in the context of topographic tidal gradients and reproductive traits at the microgeographic scale. In this issue of Molecular Ecology, Krueger-Hadfield et al. () implemented an elaborate sampling strategy with red seaweed (Chondrus crispus) from a 90-m transect stand near Roscoff and comprehensively detected genome-scale genetic differentiation and biases in ploidy level. This study not only revealed that tidal height resulted in genetic differentiation between high- and low-shore stands and restricted the genetic exchange within the high-shore habitat, but also demonstrated that intergametophytic nonrandom fertilization in C. crispus can cause significant deviation from Hardy-Weinberg equilibrium. Such new genetic insights highlight the importance of microgeographic genetic dynamics and life history characteristics for better understanding the evolutionary processes of speciation and diversification of intertidal marine organisms. © 2013 John Wiley & Sons Ltd.

  17. Planktonic Subsidies to Surf-Zone and Intertidal Communities

    Science.gov (United States)

    Morgan, Steven G.; Shanks, Alan L.; MacMahan, Jamie H.; Reniers, Ad J. H. M.; Feddersen, Falk

    2018-01-01

    Plankton are transported onshore, providing subsidies of food and new recruits to surf-zone and intertidal communities. The transport of plankton to the surf zone is influenced by wind, wave, and tidal forcing, and whether they enter the surf zone depends on alongshore variation in surf-zone hydrodynamics caused by the interaction of breaking waves with coastal morphology. Areas with gently sloping shores and wide surf zones typically have orders-of-magnitude-higher concentrations of plankton in the surf zone and dense larval settlement in intertidal communities because of the presence of bathymetric rip currents, which are absent in areas with steep shores and narrow surf zones. These striking differences in subsidies have profound consequences; areas with greater subsidies support more productive surf-zone communities and possibly more productive rocky intertidal communities. Recognition of the importance of spatial subsidies for rocky community dynamics has recently advanced ecological theory, and incorporating surf-zone hydrodynamics would be an especially fruitful line of investigation.

  18. Variable intertidal temperature explains why disease endangers black abalone

    Science.gov (United States)

    Ben-Horin, Tal; Lenihan, Hunter S.; Lafferty, Kevin D.

    2013-01-01

    Epidemiological theory suggests that pathogens will not cause host extinctions because agents of disease should fade out when the host population is driven below a threshold density. Nevertheless, infectious diseases have threatened species with extinction on local scales by maintaining high incidence and the ability to spread efficiently even as host populations decline. Intertidal black abalone (Haliotis cracherodii), but not other abalone species, went extinct locally throughout much of southern California following the emergence of a Rickettsiales-like pathogen in the mid-1980s. The rickettsial disease, a condition known as withering syndrome (WS), and associated mortality occur at elevated water temperatures. We measured abalone body temperatures in the field and experimentally manipulated intertidal environmental conditions in the laboratory, testing the influence of mean temperature and daily temperature variability on key epizootiological processes of WS. Daily temperature variability increased the susceptibility of black abalone to infection, but disease expression occurred only at warm water temperatures and was independent of temperature variability. These results imply that high thermal variation of the marine intertidal zone allows the pathogen to readily infect black abalone, but infected individuals remain asymptomatic until water temperatures periodically exceed thresholds modulating WS. Mass mortalities can therefore occur before pathogen transmission is limited by density-dependent factors.

  19. Mussel beds are biological power stations on intertidal flats

    Science.gov (United States)

    Engel, Friederike G.; Alegria, Javier; Andriana, Rosyta; Donadi, Serena; Gusmao, Joao B.; van Leeuwe, Maria A.; Matthiessen, Birte; Eriksson, Britas Klemens

    2017-05-01

    Intertidal flats are highly productive areas that support large numbers of invertebrates, fish, and birds. Benthic diatoms are essential for the function of tidal flats. They fuel the benthic food web by forming a thin photosynthesizing compartment in the top-layer of the sediment that stretches over the vast sediment flats during low tide. However, the abundance and function of the diatom film is not homogenously distributed. Recently, we have realized the importance of bivalve reefs for structuring intertidal ecosystems; by creating structures on the intertidal flats they provide habitat, reduce hydrodynamic stress and modify the surrounding sediment conditions, which promote the abundance of associated organisms. Accordingly, field studies show that high chlorophyll a concentration in the sediment co-vary with the presence of mussel beds. Here we present conclusive evidence by a manipulative experiment that mussels increase the local biomass of benthic microalgae; and relate this to increasing biomass of microalgae as well as productivity of the biofilm across a nearby mussel bed. Our results show that the ecosystem engineering properties of mussel beds transform them into hot spots for primary production on tidal flats, highlighting the importance of biological control of sedimentary systems.

  20. Development of multiwire proportional chambers

    CERN Multimedia

    Charpak, G

    1969-01-01

    It has happened quite often in the history of science that theoreticians, confronted with some major difficulty, have successfully gone back thirty years to look at ideas that had then been thrown overboard. But it is rare that experimentalists go back thirty years to look again at equipment which had become out-dated. This is what Charpak and his colleagues did to emerge with the 'multiwire proportional chamber' which has several new features making it a very useful addition to the armoury of particle detectors. In the 1930s, ion-chambers, Geiger- Muller counters and proportional counters, were vital pieces of equipment in nuclear physics research. Other types of detectors have since largely replaced them but now the proportional counter, in new array, is making a comeback.

  1. Bayesian inference on proportional elections.

    Directory of Open Access Journals (Sweden)

    Gabriel Hideki Vatanabe Brunello

    Full Text Available Polls for majoritarian voting systems usually show estimates of the percentage of votes for each candidate. However, proportional vote systems do not necessarily guarantee the candidate with the most percentage of votes will be elected. Thus, traditional methods used in majoritarian elections cannot be applied on proportional elections. In this context, the purpose of this paper was to perform a Bayesian inference on proportional elections considering the Brazilian system of seats distribution. More specifically, a methodology to answer the probability that a given party will have representation on the chamber of deputies was developed. Inferences were made on a Bayesian scenario using the Monte Carlo simulation technique, and the developed methodology was applied on data from the Brazilian elections for Members of the Legislative Assembly and Federal Chamber of Deputies in 2010. A performance rate was also presented to evaluate the efficiency of the methodology. Calculations and simulations were carried out using the free R statistical software.

  2. Comparative Proteome and Phosphoproteome Analyses during Cyprid Development of the Barnacle Balanus ( =Amphibalanus ) amphitrite

    KAUST Repository

    Zhang, Yu

    2010-06-04

    The barnacle Balanus amphitrite (=Amphibalanus amphitrite) is a major marine biofouling invertebrate worldwide. It has a complex life cycle during which the larva (called a nauplius) molts six times before transforming into the cyprid stage. The cyprid stage in B. amphitrite is the critical stage for the larval decision to attach and metamorphose. In this study, proteome and phosphoproteome alterations during cyprid development/aging and upon treatment with the antifouling agent butenolide were examined with a two-dimensional electrophoresis (2-DE) multiplexed fluorescent staining approach. Optimized protein separation strategies, including solution-phase isoelectric fractionation and narrow-pH-range 2-DE, were used in a proteomic analysis. Our results show that the differential regulation of the target proteins is highly dynamic on the levels of both protein expression and posttranslational modification. Two groups of proteins, stress-associated and energy metabolism-related proteins, are differentially expressed during cyprid development. Comparison of the control and treatment groups suggests that butenolide exerts its effects by sustaining the expression levels of these proteins. Altogether, our data suggest that proteins involved in stress regulation and energy metabolism play crucial roles in regulating larval attachment and metamorphosis of B. amphitrite. © 2010 American Chemical Society.

  3. siRNA transfection in larvae of the barnacle Amphibalanus amphitrite

    KAUST Repository

    Zhang, G.

    2015-06-25

    RNA interference (RNAi) provides an efficient and specific technique for functional genomic studies. Yet, no successful application of RNAi has been reported in barnacles. In this study, siRNA against p38 MAPK was synthesized and then transfected into A. amphitrite larvae at either the nauplius or cyprid stage, or at both stages. Effects of siRNA transfection on the p38 MAPK level were hardly detectable in the cyprids when they were transfected at the nauplius stage. In contrast, larvae that were transfected at the cyprid stage showed lower levels of p38 MAPK than the blank and reagent controls. However, significantly decreased levels of phosphorylated p38 MAPK (pp38 MAPK) and reduced settlement rates were observed only in ‘double transfections’, in which larvae were exposed to siRNA solution at both the nauplius and cyprid stages. A relatively longer transfection time and more larval cells directly exposed to siRNA might explain the higher efficiency of double transfection experiments.

  4. Transcriptome and Proteome Studies Reveal Candidate Attachment Genes during the Development of the Barnacle Amphibalanus Amphitrite

    KAUST Repository

    Al-Aqeel, Sarah; Ryu, Tae Woo; Zhang, Huoming; Chandramouli, Kondethimmanahalli; Ravasi, Timothy

    2016-01-01

    The acorn barnacle, Balanus amphitrite, is the main biofouling organism in marine environments. In the present study we profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI, and cyprid) from the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41%. We identified 65,784 expressed contigs, and a total of 1387 expressed proteins measured by quantitative proteomics. We found that osmotic stress, salt stress, hyperosmotic response and the Wnt signaling pathway were strongly up-regulated during the planktonic stage, while the MAPK pathway, lipid metabolism, and cuticle development genes were down-regulated. In the transition stage between the nauplius VI and the cyprid, genes that are involved in blood coagulation, cuticle development and eggshell formation were highly up-regulated, while the nitric oxide pathway, which stimulates the swimming and feeding response in marine invertebrates, was down-regulated. We are able to report for the first time that sound sensory system proteins are highly abundant in the nauplius VI stage, implying that these proteins are good targets for the development of new antifouling compounds. The results presented here together with the new genome-wide datasets for a non-model specie represent an important resource for the study of biofouling and development. Proteomics data are available via ProteomeXchange with identifier PXD004679.

  5. Telomere dynamics in a long-lived bird, the barnacle goose

    Directory of Open Access Journals (Sweden)

    Pauliny Angela

    2012-12-01

    Full Text Available Abstract Background Theories of ageing predict a trade-off between metabolism, reproduction, and maintenance. Species with low investment in early reproduction are thus expected to be able to evolve more efficient maintenance and repair mechanisms, allowing for a longer potential life span (intrinsic longevity. The erosion of telomeres, the protective caps at the ends of linear chromosomes, plays an important role in cellular and organismal senescence, signalling the onset of age-related disease due to accumulation of unrepaired somatic damage. Using extensive longitudinal data from a long-term study of a natural population of barnacle geese Branta leucopsis, we investigated individual rates of telomere length changes over two years in 34 birds between 0 and 22 years of age, covering almost 80% of the species’ lifespan. Results We show that telomeres in this long-lived bird are very well maintained, as theoretically expected, with an average loss rate of only 5 base pairs per year among adults. We thus found no significant relationship between change in telomere length and age. However, telomeres tended to shorten at a faster pace in juveniles compared to adults. For the first time, we demonstrate a faster telomere attrition rate in females compared to males. We found no correlation between telomere loss rate and adult survival or change in body mass. Conclusions Our results add further support for a link between longevity and telomere maintenance, and highlight the complexities of telomere dynamics in natural populations.

  6. Transcriptome and proteome studies reveal candidate attachment genes during the development of the barnacle Amphibalanus Amphitrite

    Directory of Open Access Journals (Sweden)

    Sarah Al-Aqeel

    2016-09-01

    Full Text Available The acorn barnacle, Balanus amphitrite, is the main biofouling organism in marine environments. In the present study we profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI and cyprid from the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41‰. We identified 65,784 expressed contigs, and a total of 1,387 expressed proteins measured by quantitative proteomics. We found that osmotic stress, salt stress, hyperosmotic response and the Wnt signaling pathway were strongly up-regulated during the planktonic stage, while the MAPK pathway, lipid metabolism, and cuticle development genes were down-regulated. In the transition stage between the nauplius VI and the cyprid, genes that are involved in blood coagulation, cuticle development and eggshell formation were highly up-regulated, while the nitric oxide pathway, which stimulates the swimming and feeding response in marine invertebrates, was down-regulated. We are able to report for the first time that sound sensory system proteins are highly abundant in the nauplius VI stage, implying that these proteins are good targets for the development of new antifouling compounds. The results presented here together with the new genome-wide datasets for a non-model specie represent an important resource for the study of biofouling and development.

  7. Transcriptome and Proteome Studies Reveal Candidate Attachment Genes during the Development of the Barnacle Amphibalanus Amphitrite

    KAUST Repository

    Al-Aqeel, Sarah

    2016-09-21

    The acorn barnacle, Balanus amphitrite, is the main biofouling organism in marine environments. In the present study we profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI, and cyprid) from the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41%. We identified 65,784 expressed contigs, and a total of 1387 expressed proteins measured by quantitative proteomics. We found that osmotic stress, salt stress, hyperosmotic response and the Wnt signaling pathway were strongly up-regulated during the planktonic stage, while the MAPK pathway, lipid metabolism, and cuticle development genes were down-regulated. In the transition stage between the nauplius VI and the cyprid, genes that are involved in blood coagulation, cuticle development and eggshell formation were highly up-regulated, while the nitric oxide pathway, which stimulates the swimming and feeding response in marine invertebrates, was down-regulated. We are able to report for the first time that sound sensory system proteins are highly abundant in the nauplius VI stage, implying that these proteins are good targets for the development of new antifouling compounds. The results presented here together with the new genome-wide datasets for a non-model specie represent an important resource for the study of biofouling and development. Proteomics data are available via ProteomeXchange with identifier PXD004679.

  8. siRNA transfection in larvae of the barnacle Amphibalanus amphitrite

    KAUST Repository

    Zhang, G.; He, L.-S.; Wong, Y. H.; Yu, L.; Qian, P.-Y.

    2015-01-01

    RNA interference (RNAi) provides an efficient and specific technique for functional genomic studies. Yet, no successful application of RNAi has been reported in barnacles. In this study, siRNA against p38 MAPK was synthesized and then transfected into A. amphitrite larvae at either the nauplius or cyprid stage, or at both stages. Effects of siRNA transfection on the p38 MAPK level were hardly detectable in the cyprids when they were transfected at the nauplius stage. In contrast, larvae that were transfected at the cyprid stage showed lower levels of p38 MAPK than the blank and reagent controls. However, significantly decreased levels of phosphorylated p38 MAPK (pp38 MAPK) and reduced settlement rates were observed only in ‘double transfections’, in which larvae were exposed to siRNA solution at both the nauplius and cyprid stages. A relatively longer transfection time and more larval cells directly exposed to siRNA might explain the higher efficiency of double transfection experiments.

  9. Saving Money Using Proportional Reasoning

    Science.gov (United States)

    de la Cruz, Jessica A.; Garney, Sandra

    2016-01-01

    It is beneficial for students to discover intuitive strategies, as opposed to the teacher presenting strategies to them. Certain proportional reasoning tasks are more likely to elicit intuitive strategies than other tasks. The strategies that students are apt to use when approaching a task, as well as the likelihood of a student's success or…

  10. Airborne remote sensing of estuarine intertidal radionuclide concentrations

    International Nuclear Information System (INIS)

    Rainey, M.P.

    1999-08-01

    The ability to map industrial discharges through remote sensing provides a powerful tool in environmental monitoring. Radionuclide effluents have been discharged, under authorization, into the Irish Sea from BNFL (British Nuclear Fuels Pic.) sites at Sellafield and Springfields since 1952. The quantitative mapping of this anthropogenic radioactivity in estuarine intertidal zones is crucial for absolute interpretations of radionuclide transport. The spatial resolutions of traditional approaches e.g. point sampling and airborne gamma surveys are insufficient to support geomorphic interpretations of the fate of radionuclides in estuaries. The research presented in this thesis develops the use of airborne remote sensing to derive high-resolution synoptic data on the distribution of anthropogenic radionuclides in the intertidal areas of the Ribble Estuary, Lancashire, UK. From multidate surface sediment samples a significant relationship was identified between the Sellafield-derived 137 Cs and 241 Am and clay content (r 2 = 0.93 and 0.84 respectively). Detailed in situ, and laboratory, reflectance (0.4-2.5μm) experiments demonstrated that significant relationships exist between Airborne Thematic Mapper (ATM) simulated reflectance and intertidal sediment grain-size. The spectral influence of moisture on the reflectance characteristics of the intertidal area is also evident. This had substantial implications for the timing of airborne image acquisition. Low-tide Daedalus ATM imagery (Natural Environmental Research Council) was collected of the Ribble Estuary on May 30th 1997. Preprocessing and linear unmixing of the imagery allowed accurate sub-pixel determinations of sediment clay content distributions (r 2 = 0.81). Subsequently, the established relationships between 137 Cs and 241 Am and sediment grain-size enabled the radionuclide activity distributions across the entire intertidal area (92 km 2 ) to be mapped at a geomorphic scale (1.75 m). The accuracy of these maps

  11. Changes and variations of polycyclic aromatic hydrocarbon concentrations in fish, barnacles and crabs following an oil spill in a mangrove of Guanabara Bay, Southeast Brazil.

    Science.gov (United States)

    Soares-Gomes, Abílio; Neves, Roberta L; Aucélio, Ricardo; Van Der Ven, Paulo H; Pitombo, Fábio B; Mendes, Carla L T; Ziolli, Roberta L

    2010-08-01

    On April 26th, 2005, an accident caused a leak of 60,000L of Diesel Oil Type "B", freighted by train wagons upstream on a mangrove area within Guanabara Bay, Southeast Brazil. After the accident, samples from animals with different biological requirements were collected in order to monitor polycyclic aromatic hydrocarbons concentrations for the following 12months. Sessile, mobile, carnivorous, omnivorous, organic detritus feeders, planktivorous and suspension feeders were some of the attributes compared. Concentrations of PAHs did not vary in relation to different dietary habits and the best response was from the sessile suspensivorous barnacles. A background level of <50microgkg(-1) was suggested based on the reference site and on values observed in the following months after the accident. The highest values of PAH concentrations were observed in barnacles in the first month immediately after the spill, decreasing to background levels after few months. Barnacles are suggested as a sentinel species. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. Calibrating coseismic coastal land-level changes during the 2014 Iquique (Mw=8.2) earthquake (northern Chile) with leveling, GPS and intertidal biota.

    Science.gov (United States)

    Jaramillo, Eduardo; Melnick, Daniel; Baez, Juan Carlos; Montecino, Henry; Lagos, Nelson A; Acuña, Emilio; Manzano, Mario; Camus, Patricio A

    2017-01-01

    The April 1st 2014 Iquique earthquake (MW 8.1) occurred along the northern Chile margin where the Nazca plate is subducted below the South American continent. The last great megathrust earthquake here, in 1877 of Mw ~8.8 opened a seismic gap, which was only partly closed by the 2014 earthquake. Prior to the earthquake in 2013, and shortly after it we compared data from leveled benchmarks, deployed campaign GPS instruments, continuous GPS stations and estimated sea levels using the upper vertical level of rocky shore benthic organisms including algae, barnacles, and mussels. Land-level changes estimated from mean elevations of benchmarks indicate subsidence along a ~100-km stretch of coast, ranging from 3 to 9 cm at Corazones (18°30'S) to between 30 and 50 cm at Pisagua (19°30'S). About 15 cm of uplift was measured along the southern part of the rupture at Chanabaya (20°50'S). Land-level changes obtained from benchmarks and campaign GPS were similar at most sites (mean difference 3.7±3.2 cm). Higher differences however, were found between benchmarks and continuous GPS (mean difference 8.5±3.6 cm), possibly because sites were not collocated and separated by several kilometers. Subsidence estimated from the upper limits of intertidal fauna at Pisagua ranged between 40 to 60 cm, in general agreement with benchmarks and GPS. At Chanavaya, the magnitude and sense of displacement of the upper marine limit was variable across species, possibly due to species-dependent differences in ecology. Among the studied species, measurements on lithothamnioid calcareous algae most closely matched those made with benchmarks and GPS. When properly calibrated, rocky shore benthic species may be used to accurately measure land-level changes along coasts affected by subduction earthquakes. Our calibration of those methods will improve their accuracy when applied to coasts lacking pre-earthquake data and in estimating deformation during pre-instrumental earthquakes.

  13. Uniform functional structure across spatial scales in an intertidal benthic assemblage.

    Science.gov (United States)

    Barnes, R S K; Hamylton, Sarah

    2015-05-01

    To investigate the causes of the remarkable similarity of emergent assemblage properties that has been demonstrated across disparate intertidal seagrass sites and assemblages, this study examined whether their emergent functional-group metrics are scale related by testing the null hypothesis that functional diversity and the suite of dominant functional groups in seagrass-associated macrofauna are robust structural features of such assemblages and do not vary spatially across nested scales within a 0.4 ha area. This was carried out via a lattice of 64 spatially referenced stations. Although densities of individual components were patchily dispersed across the locality, rank orders of importance of the 14 functional groups present, their overall functional diversity and evenness, and the proportions of the total individuals contained within each showed, in contrast, statistically significant spatial uniformity, even at areal scales functional groups in their geospatial context also revealed weaker than expected levels of spatial autocorrelation, and then only at the smaller scales and amongst the most dominant groups, and only a small number of negative correlations occurred between the proportional importances of the individual groups. In effect, such patterning was a surface veneer overlying remarkable stability of assemblage functional composition across all spatial scales. Although assemblage species composition is known to be homogeneous in some soft-sediment marine systems over equivalent scales, this combination of patchy individual components yet basically constant functional-group structure seems as yet unreported. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Photoacclimatory Responses of Zostera marina in the Intertidal and Subtidal Zones.

    Directory of Open Access Journals (Sweden)

    Sang Rul Park

    Full Text Available Photoacclimatory responses of the seagrass Zostera marina in the intertidal and subtidal zones were investigated by measuring chlorophyll a fluorescence parameters, photosynthetic pigments, leaf δ13C values, and shoot morphology in two bay systems. Intertidal plants had higher carotenoid concentrations than subtidal plants to avoid photodamage under excess light conditions during the day. The maximum relative electron transport rate (rETRmax and minimum saturation irradiance (Ek of the intertidal plants were higher than those of the subtidal plants, whereas photosynthetic efficiency (α and maximum quantum yield (Fv/Fm were higher in subtidal plants. The intertidal plants also had significantly greater Stern-Volmer non-photochemical quenching (NPQ than that of the subtidal plants. These results suggest that the subtidal plants photoacclimated to use limited light more efficiently, and the intertidal plants exhibited photosynthetic responses to minimize photodamage at excess irradiance. The δ13C values of leaf tissues were more negative in the intertidal plants than those in the subtidal plants, suggesting that the intertidal plants used atmospheric or dissolved CO2 for photosynthesis during emersion. Effective quantum yield (ΔF/Fm´ in the intertidal plants decreased more slowly after emersion than that in the subtidal plants, indicating higher desiccation tolerance of the intertidal plants. The intertidal plants also recovered more rapidly from desiccation damage than the subtidal plants, suggesting photosynthetic adaptation to desiccation stress. The photosynthetic plasticity of Z. marina in response to variable environmental conditions most likely allows this species to occur in the intertidal and subtidal zones.

  15. Disease proportions attributable to environment

    Directory of Open Access Journals (Sweden)

    Vineis Paolo

    2007-11-01

    Full Text Available Abstract Population disease proportions attributable to various causal agents are popular as they present a simplified view of the contribution of each agent to the disease load. However they are only summary figures that may be easily misinterpreted or over-interpreted even when the causal link between an exposure and an effect is well established. This commentary discusses several issues surrounding the estimation of attributable proportions, particularly with reference to environmental causes of cancers, and critically examines two recently published papers. These issues encompass potential biases as well as the very definition of environment and of environmental agent. The latter aspect is not just a semantic question but carries implications for the focus of preventive actions, whether centred on the material and social environment or on single individuals.

  16. PEP quark search proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Parker, S I; Harris, F; Karliner, I; Yount, D [Hawaii Univ., Honolulu (USA); Ely, R; Hamilton, R; Pun, T [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; Guryn, W; Miller, D; Fries, R [Northwestern Univ., Evanston, IL (USA)

    1981-04-01

    Proportional chambers are used in the PEP Free Quark Search to identify and remove possible background sources such as particles traversing the edges of counters, to permit geometric corrections to the dE/dx and TOF information from the scintillator and Cerenkov counters, and to look for possible high cross section quarks. The present beam pipe has a thickness of 0.007 interaction lengths (lambdasub(i)) and is followed in both arms each with 45/sup 0/ <= theta <= 135/sup 0/, ..delta..phi=90/sup 0/ by 5 proportional chambers, each 0.0008 lambdasub(i) thick with 32 channels of pulse height readout, and by 3 thin scintillator planes, each 0.003 lambdasub(i) thick. Following this thin front end, each arm of the detector has 8 layers of scintillator (one with scintillating light pipes) interspersed with 4 proportional chambers and a layer of lucite Cerenkov counters. Both the calculated ion statistics and measurements using He-CH/sub 4/ gas in a test chamber indicate that the chamber efficiencies should be >98% for q=1/3. The Landau spread measured in the test was equal to that observed for normal q=1 traversals. One scintillator plane and thin chamber in each arm will have an extra set of ADC's with a wide gate bracketing the normal one so timing errors and tails of earlier pulses should not produce fake quarks.

  17. Characterisation of the bacteria associated with barnacle, Balanus amphitrite, shell and their role in gregarious settlement of cypris larvae

    Digital Repository Service at National Institute of Oceanography (India)

    BacchettiDeGregoris, T.; Khandeparker, L.; Anil, A.C.; Mesbahi, E.; Burgess, J.G.; Clare, A.S.

    bound to a surface (Crisp and Meadows, 1963). Accordingly, the SIPC is posited to act as a contact pheromone (Clare, 2011). However, barnacle shells in their natural environment are covered by biofilm; a thick layer composed of microbial cells embedded... of Skeletonema costatum (~2 x 10 5 cells/ml) until they reached the cyprid stage (approx. for 4–5 days). Cyprids were collected by filtering through a tier of filters (pore sizes of 350 and 250 μm) in order to discard nauplii and microalgae, and stored...

  18. Recruitment of the barnacle Balanus amphitrite Darwin in a tropical estuary: implications of environmental perturbation, reproduction and larval ecology

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, D.V.; Anil, A.C.

    Biological Association of United Kingdom, 24 (9), 483-488. NIO., 1979. Master plan for pollution control of the rivers Zuari and Mandovi. Technical Report 02/79. Pechenik, J.A., Rittschof, D. & Schmidt, A.R., 1993. Influence of delayed metamorphosis... and V.P.Venugopalan), pp. 19-34. Sokal, R.R. & Rohlf, F.J., 1987. Introduction to biostatistics, 2nd ed. WH Freeman and Co. New York. Southward, A.J., 1955. On the behavior of barnacles. I. The relation of cirral and other activities to temperature...

  19. Human exploitation and benthic community structure on a tropical intertidal mudflat

    NARCIS (Netherlands)

    Boer, de W.F.; Prins, H.H.T.

    2002-01-01

    Human exploitation of intertidal marine invertebrates is known to alter benthic community structure. This study describes the impact that harvesting by women and children has on the intertidal community structure of the mudflats of the Saco on Inhaca Island, Mozambique, by comparing the benthic

  20. Recent Cnidarian-associated barnacles (Cirripedia, Balanomorpha from the Brazilian Coast

    Directory of Open Access Journals (Sweden)

    Paulo S. Young

    1988-01-01

    Full Text Available Basead on extensive collections of cnidarians from Brazilian shallow-water marine environments, new occurrences of four species of associated barnacles are cited, the first three being redescribed; Tne archaeobalanid Conopea galeata, asssociated with the gorgonians Muriceopsis sulphurea, Lophogorgia punicea and Heterogorgia sp from the States of Paraíba, Bahia, Rio de Janeiro and São Paulo; the balanid Megabalanus stultus, associated with the hydrozoans Millepora spp from Paraíba to Alagoas and from the south of Bahia to Rio de Janeiro; the pyrgomatids Megatrema madreporarum, associated with the scleractinian corals Agaricia spp from Paraíba to Alagoas and the south of Bahia, and Ceratoconcha floridanum, associated with the seleractinian coral Mussismilia hispida from Atol das Rodas and Rio de Janeiro.Com base em extensas coleções de cnidários de ambientes marinhos rasos do Brasil, novas ocorrências de quatro espécies da cracas a eles associadas são citadas, e destas três são redescritas: o arqueobalanídeo Conopea galeata, associado às gorgônias Muriceopsis sulphurea, Lophogorgia punicea e Heterogorgia sp , dos Estados da Paraíba, Bahia, Rio de Janeiro e São Paulo; o balanídeo Megabalanus stltus, associado aos hidrozoários Millepora spp, da Paraíba e Alagoas e ao sul da Bahia até o Rio de Janeiro; os pirgomatídeos Megatrema madreporarum, associado aos corais escleractíneos Agaricia sp , da Paraíba e Alagoas e sul da Bahia, e Ce atoconcha floridanum, associado ao coral escleractíneo Mussismilia hispida, do Atol das Rocas e Rio de Janeiro

  1. Influence of UV-irradiation on the nauplius larvae of the barnacle Chthamalus sp

    International Nuclear Information System (INIS)

    Hori, Masayuki; Nagayama, Shougo; Kawabe, Atsushi; Yamashita, Keiji.

    1990-01-01

    The purpose of this study is to investigate the influence of UV-irradiation on the nauplius larvae of the barnacle and to use this as the basis for researching the possibility of UV-irradiation as a new method for anti-macrofouling control. The nauplius larvae in the petri dishes were exposed to UV-irradiation (λ max = 253.7 nm), then the larval states and behaviour were observed. UV-intensisties were 3.0 mW·cm -2 -7.0 mW·cm -2 and the exposure time was 15 sec -10 min. The water in the petri dishes was changed intermittently but the larvae were not fed. The results were as follows: 1) UV-irradiation may have a delayed lethal effect and metamorphosis-inhibitory effect on the nauplius larvae. 2) The lethal effect of the sum of the dosages of UV on the larvae may nearly equate each other despite differences in each UV-intensity. 3) Within ca. 72 hr, 100 % of UV-irradiated larvae were dead with the dosage of at least 672 mW·sec·cm -2 and were incapable of swimming with the dosage of at least 168 mW·sec·cm -2 . 4) UV-irradiated larvae could not exuviate with the dosage of at least 246 mW·sec·cm -2 and could only exuviate with the dosage of 45 mW·sec·cm -2 . 5) After UV-irradiation even the 'actively swimming' larvae may have suffered some sort of physiological damage. (author)

  2. Dynamics of intertidal flats in the Loire estuary

    Science.gov (United States)

    Kervella, Stephane; Sottolichio, Aldo; Bertier, Christine

    2014-05-01

    Tidal flats form at the edges of many tidal estuaries, and are found in broad climatic regions. Their evolution plays a fundamental role in maintaining the morphodynamic equilibrium of an estuary. The Loire estuary is one of the largest macrotidal systems of the french atlantic coast. Since 200 years, its geometry has been drastically modified through channeling, deepening, embanking, infilling of secondary channels, etc. These works altered many intertidal areas. In the recent years, efforts for the rectification of the morphology have been made in order to restore the ecology of the estuary. In this context, it is crucial to better understand the dynamics of intertidal flats, still poorly understood in this estuary. The aim of this work is to analyse a series of original observations conducted for the first time in two intertidal flats of the central Lore estuary between 2008 and 2010. The tidal flats are situated in the northern bank, at 12 and 17 km upstream from the mouth respectively. Six Altus altimeters were deployed at two cross shore transects, measuring continuously and at a high-frequency bed altimetry and water level, providing information on tide and waves. At the semi-diurnal tidal scale, the surficial sediment of intertidal flats is permanently mobilized. Altimetry variations are low, and their amplitude varies as a function of tides and river flow. At the scale of several months, the sedimentation is controlled by the position of the turbidity maximum (and therefore by the river flow) and also by the tidal amplitude. During low river flow periods, altimetry variations are only due to tidal cycles. During decaying tides, suspended sediment settle mainly on the lower part of the tidal flats, forming fluid mud layers of several cm thick, which can consolidate rapidly; under rising tides, the increasing of tidal currents promotes erosion. During periods of high river flow, the turbidity maximum shifts to the lower estuary. The higher suspended sediment

  3. Incisors’ proportions in smile esthetics

    Science.gov (United States)

    Alsulaimani, Fahad F; Batwa, Waeil

    2013-01-01

    Aims: To determine whether alteration of the maxillary central and lateral incisors’ length and width, respectively, would affect perceived smile esthetics and to validate the most esthetic length and width, respectively, for the central and lateral incisors. Materials and Methods: Photographic manipulation was undertaken to produce two sets of photographs, each set of four photographs showing the altered width of the lateral incisor and length of the central length. The eight produced photographs were assessed by laypeople, dentists and orthodontists. Results: Alteration in the incisors’ proportion affected the relative smile attractiveness for laypeople (n=124), dentists (n=115) and orthodontists (n=68); dentists and orthodontists did not accept lateral width reduction of more than 0.5 mm (P<0.01), which suggests that the lateral to central incisor width ratio ranges from 54% to 62%. However, laypeople did not accept lateral width reduction of more than 1 mm (P<0.01), widening the range to be from 48% to 62%. All groups had zero tolerance for changes in central crown length (P<0.01). Conclusion: All participants recognized that the central incisors’ length changes. For lateral incisors, laypeople were more tolerant than dentists and orthodontists. This suggests that changing incisors’ proportions affects the relative smile attractiveness. PMID:24987650

  4. Associated fauna and effects of epibiotic barnacles on the relative growth and reproductive indices of Stramonita haemastoma (Gastropoda: Muricidae

    Directory of Open Access Journals (Sweden)

    Tahani El Ayari

    2015-06-01

    Full Text Available To better understand the impacts of biofouling on the biological processes of the basibiont, the effects of epibiotic barnacles on the relative growth and reproductive indices of Stramonita haemastoma (Linnaeus, 1767 were assessed. A total of 1035 specimens were collected monthly for one year from Bizerta Channel (northern Tunisia. Endobiotic species comprised the lithophagous bivalves Lithophaga aristata and Rocellaria dubia of different sizes, communicating with the outside through tiny perforations. Intra-shell tunnels and galleries also sheltered annelids and sipunculids. Epibiotic species comprised algae and highly diversified invertebrates represented by crustaceans, polychaetes, molluscs, echinoderms, ascidians, sponges, bryozoans and sipunculids, with barnacles being the most common group. Comparison of growth features between non-fouled and fouled S. haemastoma revealed higher growth in non-fouled specimens. Differences in reproductive condition indices were detected in few months, being mostly higher in non-fouled snails, but showed no asynchrony in the spawning period for either fouled or non-fouled gastropods hosts.

  5. Constant Proportion Debt Obligations (CPDOs)

    DEFF Research Database (Denmark)

    Cont, Rama; Jessen, Cathrine

    2012-01-01

    be made arbitrarily small—and thus the credit rating arbitrarily high—by increasing leverage, but the ratings obtained strongly depend on assumptions on the credit environment (high spread or low spread). More importantly, CPDO loss distributions are found to exhibit a wide range of tail risk measures......Constant Proportion Debt Obligations (CPDOs) are structured credit derivatives that generate high coupon payments by dynamically leveraging a position in an underlying portfolio of investment-grade index default swaps. CPDO coupons and principal notes received high initial credit ratings from...... the major rating agencies, based on complex models for the joint transition of ratings and spreads for all names in the underlying portfolio. We propose a parsimonious model for analysing the performance of CPDO strategies using a top-down approach that captures the essential risk factors of the CPDO. Our...

  6. First study on gene expression of cement proteins and potential adhesion-related genes of a membranous-based barnacle as revealed from Next-Generation Sequencing technology

    KAUST Repository

    Lin, Hsiu Chin; Wong, Yue Him; Tsang, Ling Ming; Chu, Ka Hou; Qian, Pei Yuan; Chan, Benny K K

    2013-01-01

    This is the first study applying Next-Generation Sequencing (NGS) technology to survey the kinds, expression location, and pattern of adhesion-related genes in a membranous-based barnacle. A total of 77,528,326 and 59,244,468 raw sequence reads of total RNA were generated from the prosoma and the basis of Tetraclita japonica formosana, respectively. In addition, 55,441 and 67,774 genes were further assembled and analyzed. The combined sequence data from both body parts generates a total of 79,833 genes of which 47.7% were shared. Homologues of barnacle cement proteins - CP-19K, -52K, and -100K - were found and all were dominantly expressed at the basis where the cement gland complex is located. This is the main area where transcripts of cement proteins and other potential adhesion-related genes were detected. The absence of another common barnacle cement protein, CP-20K, in the adult transcriptome suggested a possible life-stage restricted gene function and/or a different mechanism in adhesion between membranous-based and calcareous-based barnacles. © 2013 © 2013 Taylor & Francis.

  7. Individual inter-annual nest-site relocation behaviour drives dynamics of a recently established Barnacle Goose Branta leucopsis colony in sub-arctic Russia

    NARCIS (Netherlands)

    Karagicheva, Julia; Rakhimberdiev, Eldar; Dobrynin, Dmitry; Saveliev, Anatoly; Rozenfeld, Sofia; Pokrovskaya, Olga; Stahl, Julia; Prop, Jouke; Litvin, Konstantin

    Avian breeding colonies are generally in a continuous state of flux, some parts growing whilst others shrink as individuals move within the colony on the search for better nest-sites. We examined the role of experience in breeding patch choice by individually marked Barnacle Geese Branta leucopsis

  8. First study on gene expression of cement proteins and potential adhesion-related genes of a membranous-based barnacle as revealed from Next-Generation Sequencing technology

    KAUST Repository

    Lin, Hsiu Chin

    2013-12-12

    This is the first study applying Next-Generation Sequencing (NGS) technology to survey the kinds, expression location, and pattern of adhesion-related genes in a membranous-based barnacle. A total of 77,528,326 and 59,244,468 raw sequence reads of total RNA were generated from the prosoma and the basis of Tetraclita japonica formosana, respectively. In addition, 55,441 and 67,774 genes were further assembled and analyzed. The combined sequence data from both body parts generates a total of 79,833 genes of which 47.7% were shared. Homologues of barnacle cement proteins - CP-19K, -52K, and -100K - were found and all were dominantly expressed at the basis where the cement gland complex is located. This is the main area where transcripts of cement proteins and other potential adhesion-related genes were detected. The absence of another common barnacle cement protein, CP-20K, in the adult transcriptome suggested a possible life-stage restricted gene function and/or a different mechanism in adhesion between membranous-based and calcareous-based barnacles. © 2013 © 2013 Taylor & Francis.

  9. High-Resolution Characterization of Intertidal Geomorphology by TLS

    Science.gov (United States)

    Guarnieri, A.; Vettore, A.; Marani, M.

    2007-12-01

    Observational fluvial geomorphology has greatly benefited in the last decades from the wide availability of digital terrain data obtained by orthophotos and by means of accurate airborne laser scanner data (LiDAR). On the contrary, the spatially-distributed study of the geomorphology of intertidal areas, such as tidal flats and marshes, remains problematic owing to the small relief characterizing such environments, often of the order of a few tens of centimetres, i.e. comparable to the accuracy of state-of-the-art LiDAR data. Here we present the results of Terrestrial Laser Scanner (TLS) acquisitions performed within a tidal marsh in the Venice lagoon. The survey was performed using a Leica HDS 3000 TLS, characterized by a large Field of View (360 deg H x 270 deg V), a low beam divergence (DSM and a DTM. This is important e.g. in eco-geomorphic studies of intertidal environments, where conventional LiDAR technologies cannot easily separate first and last laser returns (because of the low vegetation height) and thus provide models of the surface as well as of the terrain. Furthermore, the DTM is shown to provide unprecedented characterizations of marsh morphology, e.g. regarding the cross-sectional properties of small-scale tidal creeks (widths of the order of 10 cm), previously observable only through conventional topographic surveys, thus not allowing a fully spatially-distributed description of their morphology.

  10. Host partitioning by parasites in an intertidal crustacean community.

    Science.gov (United States)

    Koehler, Anson V; Poulin, Robert

    2010-10-01

    Patterns of host use by parasites throughout a guild community of intermediate hosts can depend on several biological and ecological factors, including physiology, morphology, immunology, and behavior. We looked at parasite transmission in the intertidal crustacean community of Lower Portobello Bay, Dunedin, New Zealand, with the intent of: (1) mapping the flow of parasites throughout the major crustacean species, (2) identifying hosts that play the most important transmission role for each parasite, and (3) assessing the impact of parasitism on host populations. The most prevalent parasites found in 14 species of crustaceans (635 specimens) examined were the trematodes Maritrema novaezealandensis and Microphallus sp., the acanthocephalans Profilicollis spp., the nematode Ascarophis sp., and an acuariid nematode. Decapods were compatible hosts for M. novaezealandensis, while other crustaceans demonstrated lower host suitability as shown by high levels of melanized and immature parasite stages. Carapace thickness, gill morphology, and breathing style may contribute to the differential infection success of M. novaezealandensis and Microphallus sp. in the decapod species. Parasite-induced host mortality appears likely with M. novaezealandensis in the crabs Austrohelice crassa, Halicarcinus varius, Hemigrapsus sexdentatus, and Macrophthalmus hirtipes, and also with Microphallus sp. in A. crassa. Overall, the different parasite species make different use of available crustacean intermediate hosts and possibly contribute to intertidal community structure.

  11. Mollusks: how are they arranged in the rocky intertidal zone?

    Directory of Open Access Journals (Sweden)

    Débora R. A. Veras

    2013-06-01

    Full Text Available Mollusks occupy different kinds of environments, including the intertidal zone. The present study investigated the spatial distribution of mollusks on beach rocks of the intertidal zone of Pacheco Beach in the state of Ceará, Brazil. Sampling occurred from August 2006 to September 2007. Across two transects, six samples of 0.25 m² were collected monthly in gaps of 30 m (0 m, 30 m, 60 m, 90 m, 120 m and 150 m. The mollusks were counted in field, and samples of sediment and algae were taken for further analysis. A total of 74,515 individuals were found and classified into 67 species, 52 genera and 39 families. Gastropods were predominant, corresponding to 73.1% of the species, followed by bivalves (22.4% and chitons (4.5%. Caecum ryssotitum de Folin, 1867 was the most abundant taxon, representing 68.8% of total specimen findings. In general, species were mostly found in Middle Littoral zone (samples 60 m and 90 m, suggesting that the greater number of microenvironments available in this area may contribute to establishment and survival.

  12. Position-sensitive proportional counter

    International Nuclear Information System (INIS)

    Kopp, M.K.

    1980-01-01

    A position-sensitive proportional counter circuit uses a conventional (low-resistance, metal-wire anode) counter for spatial resolution of an ionizing event along the anode, which functions as an RC line. A pair of preamplifiers at the anode ends act as stabilized active-capacitance loads, each comprising a series-feedback, low-noise amplifier and a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction of handling of the anodes, and stabilizes the anode resistivity at high count rates (>10 6 counts/sec). (author)

  13. Impact of intertidal area characteristics on estuarine tidal hydrodynamics: A modelling study for the Scheldt Estuary

    Science.gov (United States)

    Stark, J.; Smolders, S.; Meire, P.; Temmerman, S.

    2017-11-01

    Marsh restoration projects are nowadays being implemented as ecosystem-based strategies to reduce flood risks and to restore intertidal habitat along estuaries. Changes in estuarine tidal hydrodynamics are expected along with such intertidal area changes. A validated hydrodynamic model of the Scheldt Estuary is used to gain fundamental insights in the role of intertidal area characteristics on tidal hydrodynamics and tidal asymmetry in particular through several geomorphological scenarios in which intertidal area elevation and location along the estuary is varied. Model results indicate that the location of intertidal areas and their storage volume relative to the local tidal prism determine the intensity and reach along the estuary over which tidal hydrodynamics are affected. Our model results also suggest that intertidal storage areas that are located within the main estuarine channel system, and hence are part of the flow-carrying part of the estuary, may affect tidal hydrodynamics differently than intertidal areas that are side-basins of the main estuarine channel, and hence only contribute little to the flow-carrying cross-section of the estuary. If tidal flats contribute to the channel cross-section and exert frictional effects on the tidal propagation, the elevation of intertidal flats influences the magnitude and direction of tidal asymmetry along estuarine channels. Ebb-dominance is most strongly enhanced if tidal flats are around mean sea level or slightly above. Conversely, flood-dominance is enhanced if the tidal flats are situated low in the tidal frame. For intertidal storage areas at specific locations besides the main channel, flood-dominance in the estuary channel peaks in the vicinity of those areas and generally reduces upstream and downstream compared to a reference scenario. Finally, the model results indicate an along-estuary varying impact on the tidal prism as a result of adding intertidal storage at a specific location. In addition to known

  14. Larval development and post-settlement metamorphosis of the barnacle Balanus albicostatus Pilsbry and the serpulid polychaete Pomatoleios kraussii Baird: Impact of a commonly used antifouling biocide, Irgarol 1051

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Desai, D.V.; Shirayama, Y.

    The impact of a commonly-used antifouling algicide, Irgarol 1051, on the larval development and post-settlement metamorphosis of the barnacle, Balanus albicostatus Pilsbry (Crustacea: Cirripedia), and the larval metamorphosis of a serpulid...

  15. Impact of oil spill on intertidal organisms in Bahrain

    International Nuclear Information System (INIS)

    Mohamed, S.A.

    1991-01-01

    This paper reports on a study carried out after a major oil spill hit the coasts of Bahrain in 1988. A total of fifteen stations around the Island of Bahrain were monitored for a period of six months in order to measure the impact of the spill on marine organisms and in particular those living in the intertidal zone. Large quantities of heavy hydrocarbons accumulated on the shores and caused death or serious damage to many organisms, including birds and fishes. The spill first hit the northwest shores. The oil spill was also reported to be the main factor in damaging the traditional fishing traps in the coastal waters, which caused serious effects on the fish catch for seven months

  16. Artificial radionuclides in an intertidal sediment from northwest England

    International Nuclear Information System (INIS)

    Morris, K.; Keith-Roach, M.J.; Butterworth, J.C.; Livens, L.K.; Day, J.P.; Hursthouse, A.S.; Fifield, L.K.; Bardgett, R.D.

    1998-01-01

    An intertidal sediment core has been analysed for the principal transuranium elements present in the BNFL Sellafield radioactive waste discharges (Np, Pu, Am) and the high yield fission products 99 Tc and 137 Cs. Interstitial water samples were collected using porous cup samplers and early results from these analyses show that there is a pronounced seasonality in the pattern of dissolved Pu, which apparently relates to changes in dissolved Fe and Mn. More recent work has concentrated on the characterization of changes in the sediment microbial community and on the development of analytical methods for the analysis of dissolved Np, apparently the most readily mobilized of the transuranic elements, which is present at concentrations of the order of 10 8 atoms/litre

  17. Infestation and morphological identification of the stalked epizoic barnacle Octolasmis on the blue crab Portunus pelagicus from the Red Sea

    Science.gov (United States)

    Afifi Khattab, Rafat

    2017-09-01

    The intensity of infestation of the epizoic stalked barnacle Octolasmis on the blue crab was calculated for a total of 180 individuals collected around Jeddah, the western Red Sea Saudi coast. More than 90% of the crabs were found bearing the Octolasmis at a prevalence rate of 92% and mean intensity of 18.5±18.6 (0-127 epibiont per host). The intensity of infestation increased with host size in the range 90-135 mm. Generally, females were more infested (69%) than the males (31%). Octolasmis angulata occurred mostly on the gills, and the lower side of the gill chambers was more infested (84%) than the upper side (16%) and the left side of gills was also more infested than the right side in both males and females. Further studies are still needed to examine the commensal relationship and its impact on the fishery market of the Red Sea blue crab populations.

  18. Biomonitoring of trace metal bioavailabilities to the barnacle Amphibalanus amphitrite along the Iranian coast of the Persian Gulf.

    Science.gov (United States)

    Nasrolahi, A; Smith, B D; Ehsanpour, M; Afkhami, M; Rainbow, P S

    2014-10-01

    The fouling barnacle Amphibalanus amphitrite is a cosmopolitan biomonitor of trace metal bioavailabilities, with an international comparative data set of body metal concentrations. Bioavailabilities of As, Cd, Cr, Cu, Fe, Mn, Pb, V and Zn to A. amphitrite were investigated at 19 sites along the Iranian coast of the understudied Persian Gulf. Commercial and fishing ports showed extremely high Cu bioavailabilities, associated with high Zn bioavailabilities, possibly from antifouling paints and procedures. V availability was raised at one port, perhaps associated with fuel leakage. Cd bioavailabilities were raised at sites near the Strait of Hormuz, perhaps affected by adjacent upwelling off Oman. The As data allow a reinterpretation of the typical range of accumulated As concentrations in A. amphitrite. The Persian Gulf data add a new region to the A. amphitrite database, confirming its importance in assessing the ecotoxicologically significant trace metal contamination of coastal waters across the world. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Microsatellite loci discovery from next-generation sequencing data and loci characterization in the epizoic barnacle Chelonibia testudinaria (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Christine Ewers-Saucedo

    2016-05-01

    Full Text Available Microsatellite markers remain an important tool for ecological and evolutionary research, but are unavailable for many non-model organisms. One such organism with rare ecological and evolutionary features is the epizoic barnacle Chelonibia testudinaria (Linnaeus, 1758. Chelonibia testudinaria appears to be a host generalist, and has an unusual sexual system, androdioecy. Genetic studies on host specificity and mating behavior are impeded by the lack of fine-scale, highly variable markers, such as microsatellite markers. In the present study, we discovered thousands of new microsatellite loci from next-generation sequencing data, and characterized 12 loci thoroughly. We conclude that 11 of these loci will be useful markers in future ecological and evolutionary studies on C. testudinaria.

  20. Microsatellite loci discovery from next-generation sequencing data and loci characterization in the epizoic barnacle Chelonibia testudinaria (Linnaeus, 1758)

    Science.gov (United States)

    Zardus, John D.; Wares, John P.

    2016-01-01

    Microsatellite markers remain an important tool for ecological and evolutionary research, but are unavailable for many non-model organisms. One such organism with rare ecological and evolutionary features is the epizoic barnacle Chelonibia testudinaria (Linnaeus, 1758). Chelonibia testudinaria appears to be a host generalist, and has an unusual sexual system, androdioecy. Genetic studies on host specificity and mating behavior are impeded by the lack of fine-scale, highly variable markers, such as microsatellite markers. In the present study, we discovered thousands of new microsatellite loci from next-generation sequencing data, and characterized 12 loci thoroughly. We conclude that 11 of these loci will be useful markers in future ecological and evolutionary studies on C. testudinaria. PMID:27231653

  1. Effects of total solar eclipse on the behavioural and metabolic activities of tropical intertidal animals

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Ansari, Z.A.; Verlecar, X.N.; Harkantra, S.N.

    To study the effects of total solar eclipse of 16th Feb. 1980, on the behaviour and metabolic activities of intertidal invertebrates - nematodes, gastropods and bivalves - having different habitat preference a set of relevant observations, covering...

  2. A quantitative analysis of fine scale distribution of intertidal meiofauna in response to food resources

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Gauns, M.

    Fine scale vertical and spatial distribution of meiofauna in relation to food abundance was studied in the intertidal sediment at Dias Beach. The major abiotic factors showed significant changes and progressive fine scale decrease in vertical...

  3. Substrate deposit effect on the characteristic of an intertidal macroalgal community

    Digital Repository Service at National Institute of Oceanography (India)

    Imchen, T.

    Present study consists the effect of substrate deposit (silt, clay, sand, gravel and shards of shells) on the characteristic of an intertidal rocky shore macroalgae Macroalgal assemblage was segregated from substrate deposit in two stages Substrate...

  4. Studies on the intertidal macrofauna of the sandy beach at Kavarati atoll (Lakshadweep)

    Digital Repository Service at National Institute of Oceanography (India)

    Narayanan, B.; Sivadas, P.

    The distribution of macrofauna in Kavaratti Atoll is studied in the intertidal region for over a period of 13 months. Several diversity in the faunal composition was not observed. The polychaete Scoloplos sp. and the bivalve Mesodesma glabratum were...

  5. Impact of industrial effluents on geochemical association of metals within intertidal sediments of a creek

    Digital Repository Service at National Institute of Oceanography (India)

    Volvoikar, S.P.; Nayak, G.N.

    Metal speciation studies were carried out on three intertidal core sediments of the industrially impacted Dudh creek located along west coast of India Metals indicated a drastic increase in the bioavailable fraction towards the surface of the cores...

  6. NODC Standard Format Intertidal Organisms and Habitats (F030) Data (1974-1980) (NODC Accession 0014153)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data type contains data from field sampling of marine organisms in intertidal or subtidal habitats. The data were collected to provide information about species...

  7. Puget Sound Intertidal Habitat Inventory; Puget Sound Ambient Monitoring Program, 1996 (NODC Accession 9900221)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Puget Sound's intertidal areas provide habitat for species of commercial, recreational, biotic, and aesthetic value. Habitat is a critical ecosystem component -- it...

  8. iTRAQ-Based Proteomic Profiling of the Barnacle Balanus amphitrite in Response to the Antifouling Compound Meleagrin

    KAUST Repository

    Han, Zhuang

    2013-05-03

    Marine biofouling refers to the unwanted accumulation of fouling organisms, such as barnacles, on artificial surfaces, resulting in severe consequences for marine industries. Meleagrin is a potential nontoxic antifoulant that is isolated from the fungus Penicillium sp.; however, its mechanistic effect mode of action on larval settlement remains unknown. Here, we applied iTRAQ coupled with 2D LC-MS/MS proteomic analysis to investigate the effect of meleagrin on the proteomic expression profile of cyprid development and aging in the barnacle Balanus amphitrite. Fifty proteins were differentially expressed in response to treatment with meleagrin, among which 26 proteins were associated with cyprid development/aging and 24 were specifically associated with the meleagrin treatment. The 66 proteins that were associated with aging only remained unaltered during exposure to meleagrin. Using KEGG analysis, those proteins were assigned to several groups, including metabolic pathways, ECM-receptor interactions, and the regulation of the actin cytoskeleton. Among the 24 proteins that were not related to the development/aging process, expression of the cyprid major protein (CMP), a vitellogenin-like protein, increased after the meleagrin treatment, which suggested that meleagrin might affect the endocrine system and prevent the larval molting cycle. With the exception of the chitin binding protein that mediates the molting process and ATPase-mediated energy processes, the majority of proteins with significant effects in previous studies in response to cyprid treatment with butenolide and polyether B remained unchanged in the present study, suggesting that meleagrin may exhibit a different mechanism. © 2013 American Chemical Society.

  9. The Story of a Hitchhiker: Population Genetic Patterns in the Invasive Barnacle Balanus(Amphibalanus improvisus Darwin 1854.

    Directory of Open Access Journals (Sweden)

    Anna-Lisa Wrange

    Full Text Available Understanding the ecological and evolutionary forces that determine the genetic structure and spread of invasive species is a key component of invasion biology. The bay barnacle, Balanus improvisus (= Amphibalanus improvisus, is one of the most successful aquatic invaders worldwide, and is characterised by broad environmental tolerance. Although the species can spread through natural larval dispersal, human-mediated transport through (primarily shipping has almost certainly contributed to the current global distribution of this species. Despite its worldwide distribution, little is known about the phylogeography of this species. Here, we characterize the population genetic structure and model dispersal dynamics of the barnacle B. improvisus, and describe how human-mediated spreading via shipping as well as natural larval dispersal may have contributed to observed genetic variation. We used both mitochondrial DNA (cytochrome c oxidase subunit I: COI and nuclear microsatellites to characterize the genetic structure in 14 populations of B. improvisus on a global and regional scale (Baltic Sea. Genetic diversity was high in most populations, and many haplotypes were shared among populations on a global scale, indicating that long-distance dispersal (presumably through shipping and other anthropogenic activities has played an important role in shaping the population genetic structure of this cosmopolitan species. We could not clearly confirm prior claims that B. improvisus originates from the western margins of the Atlantic coasts; although there were indications that Argentina could be part of a native region. In addition to dispersal via shipping, we show that natural larval dispersal may play an important role for further colonisation following initial introduction.

  10. iTRAQ-Based Proteomic Profiling of the Barnacle Balanus amphitrite in Response to the Antifouling Compound Meleagrin

    KAUST Repository

    Han, Zhuang; Sun, Jin; Zhang, Yu; He, Fei; Xu, Ying; Matsumura, Kiyotaka; He, Li-Sheng; Qiu, Jian-Wen; Qi, Shu-Hua; Qian, Pei-Yuan

    2013-01-01

    Marine biofouling refers to the unwanted accumulation of fouling organisms, such as barnacles, on artificial surfaces, resulting in severe consequences for marine industries. Meleagrin is a potential nontoxic antifoulant that is isolated from the fungus Penicillium sp.; however, its mechanistic effect mode of action on larval settlement remains unknown. Here, we applied iTRAQ coupled with 2D LC-MS/MS proteomic analysis to investigate the effect of meleagrin on the proteomic expression profile of cyprid development and aging in the barnacle Balanus amphitrite. Fifty proteins were differentially expressed in response to treatment with meleagrin, among which 26 proteins were associated with cyprid development/aging and 24 were specifically associated with the meleagrin treatment. The 66 proteins that were associated with aging only remained unaltered during exposure to meleagrin. Using KEGG analysis, those proteins were assigned to several groups, including metabolic pathways, ECM-receptor interactions, and the regulation of the actin cytoskeleton. Among the 24 proteins that were not related to the development/aging process, expression of the cyprid major protein (CMP), a vitellogenin-like protein, increased after the meleagrin treatment, which suggested that meleagrin might affect the endocrine system and prevent the larval molting cycle. With the exception of the chitin binding protein that mediates the molting process and ATPase-mediated energy processes, the majority of proteins with significant effects in previous studies in response to cyprid treatment with butenolide and polyether B remained unchanged in the present study, suggesting that meleagrin may exhibit a different mechanism. © 2013 American Chemical Society.

  11. Are seagrass beds indicators of anthropogenic nutrient stress in the rocky intertidal?

    International Nuclear Information System (INIS)

    Honig, Susanna E.; Mahoney, Brenna; Glanz, Jess S.; Hughes, Brent B.

    2017-01-01

    It is well established that anthropogenic nutrient inputs harm estuarine seagrasses, but the influence of nutrients in rocky intertidal ecosystems is less clear. In this study, we investigated the effect of anthropogenic nutrient loading on Phyllospadix spp., a rocky intertidal seagrass, at local and regional scales. At sites along California, Washington, and Oregon, we demonstrated a significant, negative correlation of urban development and Phyllospadix bed thickness. These results were echoed locally along an urban gradient on the central California coast, where Phyllospadix shoot δ 15 N was negatively associated with Phyllospadix bed thickness, and experimentally, where nutrient additions in mesocosms reduced Phyllospadix shoot formation and increased epiphytic cover on Phyllospadix shoots. These findings provide evidence that coastal development can threaten rocky intertidal seagrasses through increased epiphytism. Considering that seagrasses provide vital ecosystem services, mitigating eutrophication and other factors associated with development in the rocky intertidal coastal zone should be a management priority. - Highlights: • The effect of nutrient loading on rocky intertidal seagrasses is not well studied. • Regionally, development was negatively associated with Phyllospadix bed thickness. • Locally, shoot δ 15 N was negatively associated with Phyllospadix bed thickness. • Mesocosms with added nutrients had a net loss in shoots and increased epiphytes. • Nutrient loading may have a negative effect on intertidal seagrass bed health.

  12. Using GPS-surveyed intertidal zones to determine the validity of shorelines automatically mapped by Landsat water indices

    Science.gov (United States)

    Kelly, Joshua T.; Gontz, Allen M.

    2018-03-01

    Satellite remote sensing has been used extensively in a variety of shoreline studies and validated using aerial photography. This ground truth method only represents an instantaneous depiction of the shoreline at the time of acquisition and does not take into account the spatial and temporal variability of the dynamic shoreline boundary. Landsat 8‧s Operational Land Imager sensor's capability to accurately delineate a shoreline is assessed by comparing all known Landsat water index-derived shorelines with two GPS-surveyed intertidal zones that coincide with the satellite flyover date, one of which had near-neap tide conditions. Seven indices developed for automatically classifying water pixels were evaluated for their ability to delineate shorelines. The shoreline is described here as the area above and below maximum low and high tide, otherwise known as the intertidal zone. The high-water line, or wet/dry sediment line, was chosen as the shoreline indicator to be mapped using a handheld GPS. The proportion of the Landsat-derived shorelines that fell within this zone and their alongshore profile lengths were calculated. The most frequently used water index and the predecessor to Modified Normalized Difference Water Index (MNDWI), Normalized Difference Water Index (NDWI), was found to be the least accurate by a significant margin. Other indices required calibration of their threshold value to achieve accurate results, thus diminishing their replicability success for other regions. MNDWI was determined to be the best index for automated shoreline mapping, based on its superior accuracy and repeatable, stable threshold value.

  13. Global Drought Proportional Economic Loss Risk Deciles

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Drought Proportional Economic Loss Risk Deciles is a 2.5 minute grid of drought hazard economic loss as proportions of Gross Domestic Product (GDP) per...

  14. Impossibility Theorem in Proportional Representation Problem

    International Nuclear Information System (INIS)

    Karpov, Alexander

    2010-01-01

    The study examines general axiomatics of Balinski and Young and analyzes existed proportional representation methods using this approach. The second part of the paper provides new axiomatics based on rational choice models. New system of axioms is applied to study known proportional representation systems. It is shown that there is no proportional representation method satisfying a minimal set of the axioms (monotonicity and neutrality).

  15. Cognitive and Metacognitive Aspects of Proportional Reasoning

    Science.gov (United States)

    Modestou, Modestina; Gagatsis, Athanasios

    2010-01-01

    In this study we attempt to propose a new model of proportional reasoning based both on bibliographical and research data. This is impelled with the help of three written tests involving analogical, proportional, and non-proportional situations that were administered to pupils from grade 7 to 9. The results suggest the existence of a…

  16. Evaluating Middle Years Students' Proportional Reasoning

    Science.gov (United States)

    Hilton, Annette; Dole, Shelley; Hilton, Geoff; Goos, Merrilyn; O'Brien, Mia

    2012-01-01

    Proportional reasoning is a key aspect of numeracy that is not always developed naturally by students. Understanding the types of proportional reasoning that students apply to different problem types is a useful first step to identifying ways to support teachers and students to develop proportional reasoning in the classroom. This paper describes…

  17. Levels of chromium contamination in the estuary of the Iraja river (Guanabara Bay) and experimental incorporation of 51Cr in barnacles (Balanus sp)

    International Nuclear Information System (INIS)

    Weerelt, M.D.M.V.

    1982-01-01

    Levels were determined of chromium contamination in the estuary of Iraja River, produced by an electroplating industry located 3 km upstream the study area. Uptake-and release kinetics of Cr(VI) and Cr(III) in barnacles (Balanus sp.) were studied. Samples of barnacles and suspended particles from Guanabara Bay were analysed. Chromium concentrations (dry weight) ranged from not detectable (ND) to 154,66 μg/g for soft tissues and from ND to 423,76 μg/g for suspended particles. Mean of maximum concentrations of chromium in samples from Guanabara Bay are 3 and 4 times above those of identical samples from control area (Coroa Grande). Soft tissues presented a concentration factor (CF) of 10 3 related to chromium available in suspended particles. 51 Cr(VI) is preferentiably incorparated by soft tissues (biological half life being 100 days). Chromium uptake by Balanus sp from solution is as significant as it is from particulate matter available in sea water from experimental sets. CF for Cr(VI) in soft tissues in laboratory conditions was 10 2 related to 51 Cr present in sea water. Environmental chromium contamination was found to be of the same order of magnitude or above levels reported for other areas subjected to industrial impacts. Barnacles appear to be able to accumulate chromium in soft tissues from the available metal in the environment. Cr(VI) is the critical form, being greatly accumulated in soft tissues of barnacles, that act as a long-term integrator of this metal. For Cr(III), this organism can only be regarded as an instantaneous indicator of environmental contamination of chromium attached to suspended particles. (M.A.) [pt

  18. Structure of molluscan assemblages in sheltered intertidal unconsolidated environments

    Directory of Open Access Journals (Sweden)

    Márcia Regina Denadai

    2005-09-01

    Full Text Available The molluscan macrofauna from 13 oceanic sheltered intertidal unconsolidated environments and its relationship with abiotic factors were studied in order to establish the degree of species richness and to understand the role environment plays in structuring such assemblages. Four distinct intertidal habitat types were recognized based on molluscan assemblage descriptors (diversity, richness and density and abiotic characteristics. The mean grain size (in phy units and the beach slope showed a negative relationship with the diversity, richness and density. Coarser sediments were favorable to molluscan fauna in the study areas, contrasting the well-known negative effect of this type of sand on fauna in typical oceanic beaches. The low-tide terraces, typical from tide-dominated areas, and the presence of physical (rocky fragments and biogenic (gravel structures, were also associated to the higher values of richness. The high richness in the study area as a whole seemed to be a direct consequence of its environmental heterogeneity, once it was composed by quite distinct habitat types.A malacofauna de 13 ambientes oceânicos, protegidos, entremarés e não-consolidados e sua relação com os fatores abióticos foram estudados com o intuito de conhecer a riqueza de espécies e compreender o papel dos fatores abióticos na estruturação das associações. Quatro tipos distintos de ambiente entremarés foram reconhecidos com base nos descritores da comunidade (diversidade, riqueza e densidade e nas características abióticas. O tamanho médio do grão de areia (em phy e a inclinação da praia mostraram uma relação negativa com a diversidade, riqueza e densidade. Sedimentos grossos foram favoráveis à fauna de moluscos nas áreas estudadas, contrastando o bem conhecido efeito negativo deste tipo de areia sobre a fauna em praias oceânicas típicas. Os terraços de maré baixa, típicos de áreas dominadas pela maré, e a presença de estruturas

  19. MKK3 Was Involved in Larval Settlement of the Barnacle Amphibalanus amphitrite through Activating the Kinase Activity of p38MAPK

    KAUST Repository

    Zhang, Gen

    2013-07-29

    The p38 mitogen-activated protein kinase (p38MAPK) plays a key role in larval settlement of the barnacle Amphibalanus amphitrite. To study the signaling pathway associated with p38MAPK during larval settlement, we sought to identify the upstream kinase of p38MAPK. Three MKKs (MKK3, MKK4 and MKK7) and three MAPKs (p38MAPK, ERK and JNK) in A. amphitrite were cloned and recombinantly expressed in E. coli. Through kinase assays, we found that MKK3, but not MKK4 or MKK7, phosphorylated p38MAPK. Furthermore, MKK3 activity was specific to p38MAPK, as it did not phosphorylate ERK or JNK. To further investigate the functional relationship between MKK3 and p38MAPK in vivo, we studied the localization of phospho-MKK3 (pMKK3) and MKK3 by immunostaining. Consistent with the patterns of p38MAPK and phospho-p38MAPK (pp38MAPK), pMKK3 and MKK3 mainly localized to the antennules of the cyprids. Western blot analysis revealed that pMKK3 levels, like pp38MAPK levels, were elevated at cyprid stage, compared to nauplii and juvenile stages. Moreover, pMKK3 levels increased after treatment with adult barnacle crude extracts, suggesting that MKK3 might mediate the stimulatory effects of adult barnacle extracts on the p38MAPK pathway. © 2013 Zhang et al.

  20. MKK3 Was Involved in Larval Settlement of the Barnacle Amphibalanus amphitrite through Activating the Kinase Activity of p38MAPK

    KAUST Repository

    Zhang, Gen; He, Li-Sheng; Wong, Yue Him; Qian, Pei-Yuan

    2013-01-01

    The p38 mitogen-activated protein kinase (p38MAPK) plays a key role in larval settlement of the barnacle Amphibalanus amphitrite. To study the signaling pathway associated with p38MAPK during larval settlement, we sought to identify the upstream kinase of p38MAPK. Three MKKs (MKK3, MKK4 and MKK7) and three MAPKs (p38MAPK, ERK and JNK) in A. amphitrite were cloned and recombinantly expressed in E. coli. Through kinase assays, we found that MKK3, but not MKK4 or MKK7, phosphorylated p38MAPK. Furthermore, MKK3 activity was specific to p38MAPK, as it did not phosphorylate ERK or JNK. To further investigate the functional relationship between MKK3 and p38MAPK in vivo, we studied the localization of phospho-MKK3 (pMKK3) and MKK3 by immunostaining. Consistent with the patterns of p38MAPK and phospho-p38MAPK (pp38MAPK), pMKK3 and MKK3 mainly localized to the antennules of the cyprids. Western blot analysis revealed that pMKK3 levels, like pp38MAPK levels, were elevated at cyprid stage, compared to nauplii and juvenile stages. Moreover, pMKK3 levels increased after treatment with adult barnacle crude extracts, suggesting that MKK3 might mediate the stimulatory effects of adult barnacle extracts on the p38MAPK pathway. © 2013 Zhang et al.

  1. Proportioning of U3O8 powder

    International Nuclear Information System (INIS)

    Cermak, V.; Markvart, M.; Novy, P.; Vanka, M.

    1989-01-01

    The tests are briefly described or proportioning U 3 O 8 powder of a granulometric grain size range of 0-160 μm using a vertical screw, a horizontal dual screw and a vibration dispenser with a view to proportioning very fine U 3 O 8 powder fractions produced in the oxidation of UO 2 fuel pellets. In the tests, the evenness of proportioning was assessed by the percentage value of the proportioning rate spread measured at one-minute intervals at a proportioning rate of 1-3 kg/h. In feeding the U 3 O 3 in a flame fluorator, it is advantageous to monitor the continuity of the powder column being proportioned and to assess it radiometrically by the value of the proportioning rate spread at very short intervals (0.1 s). (author). 10 figs., 1 tab., 12 refs

  2. Determining the Contribution of Non-Carbonate Alkalinity from Intertidal Salt Marshes to Coastal Buffering Capacity

    Science.gov (United States)

    Anderson, L. B.; Gonneea, M. E.; Wang, A. Z.; Chu, S. N.

    2016-02-01

    Coastal ocean acidification varies with high magnitude and frequency due to both natural and anthropogenic factors, and levels of acidity in coastal waters have important consequences for environmental concerns such as local settlement of bivalve populations. Therefore, it is useful to fully evaluate measurements that increase understanding of coastal ocean acidification dynamics. This study focuses on the quantification and characterization of alkalinity, the ability of a specific water parcel to buffer against inputs of acidity. There has been limited research on the magnitude and composition of non-carbonate alkalinity (NCA) generated in coastal environments. Specifically, this study evaluates the contribution of NCA to total alkalinity (TA) in an intertidal salt marsh, assesses NCA dynamics within the marsh, and begins to determine composition of NCA. We demonstrated that it was possible to develop a CO2-free full titration system modeled after Cai et al. (1998) that produced reasonable values for TA and NCA. From initial use of this system, it was evident that NCA was a significant contributor to TA within the Sage Lot Pond salt marsh, and that NCA was dominated by organic/unknown alkalinity. Preliminary observations indicated that NCA variability in the marsh was directly proportional to water flux entering the tidal creek from Sage Lot Pond. The source of higher NCA concentrations in Sage Lot Pond was unknown, but may have been due to organic/unknown alkalinity generated in a different part of the marsh and exported to our specific tidal creek site. Preliminary assessment of NCA composition indicates an acid/base species with a pK value of 6.46. From evaluation of NCA magnitude and relation to water flux, it is reasonable to conclude that NCA generated within salt marshes may be a significant source of buffering capacity to the coastal ocean.

  3. Intertidal oysters reach their physiological limit in a future high-CO2 world.

    Science.gov (United States)

    Scanes, Elliot; Parker, Laura M; O'Connor, Wayne A; Stapp, Laura S; Ross, Pauline M

    2017-03-01

    Sessile marine molluscs living in the intertidal zone experience periods of internal acidosis when exposed to air (emersion) during low tide. Relative to other marine organisms, molluscs have been identified as vulnerable to future ocean acidification; however, paradoxically it has also been shown that molluscs exposed to high CO 2 environments are more resilient compared with those molluscs naive to CO 2 exposure. Two competing hypotheses were tested using a novel experimental design incorporating tidal simulations to predict the future intertidal limit of oysters in a high-CO 2 world; either high-shore oysters will be more tolerant of elevated P CO 2 because of their regular acidosis, or elevated P CO 2  will cause high-shore oysters to reach their limit. Sydney rock oysters, Saccostrea glomerata , were collected from the high-intertidal and subtidal areas of the shore and exposed in an orthogonal design to either an intertidal or a subtidal treatment at ambient or elevated P CO 2 , and physiological variables were measured. The combined treatment of tidal emersion and elevated P CO 2  interacted synergistically to reduce the haemolymph pH (pH e ) of oysters, and increase the P CO 2  in the haemolymph ( P e,CO 2 ) and standard metabolic rate. Oysters in the intertidal treatment also had lower condition and growth. Oysters showed a high degree of plasticity, and little evidence was found that intertidal oysters were more resilient than subtidal oysters. It is concluded that in a high-CO 2 world the upper vertical limit of oyster distribution on the shore may be reduced. These results suggest that previous studies on intertidal organisms that lacked tidal simulations may have underestimated the effects of elevated P CO 2 . © 2017. Published by The Company of Biologists Ltd.

  4. Conducta de forrajeo del gastrópodo Acanthina monodon Pallas, 1774 (Gastropoda: Muricidae en el intermareal rocoso de Chile central Foraging behavior of the gastropod Acanthina monodon Pallas, 1774 (Gastropoda: Muricidae in the intertidal rocky shores of central Chile

    Directory of Open Access Journals (Sweden)

    RUBÉN E. SOTO

    2004-03-01

    Full Text Available En el presente trabajo investigamos aspectos de la ecología y conducta de forrajeo de Acanthina monodon, un gastrópodo murícido que habita en el intermareal rocoso de Chile central. En terreno, estudiamos las variaciones temporales en su distribución, densidad y dieta. En el laboratorio, cuantificamos la tasa de consumo, las preferencias alimentarias, el tiempo de ingestión y la rentabilidad energética obtenida con distintos tipos de presas mediante experimentos y registros en video. Las mayores densidades de individuos de A. monodon fueron observadas en la franja intermareal cercana al nivel cero de marea. En terreno, A. monodon realiza sus actividades de forrajeo principalmente durante la noche y su dieta consistió principalmente de mitílidos (95 % y cirripedios (5 %. La composición de la dieta de A. monodon en terreno presentó variaciones temporales las cuales dependerían principalmente de cambios en la oferta de los distintos tipos de mitílidos presentes en terreno durante los dos años de muestreo. En el laboratorio, los individuos de Acanthina presentaron preferencias alimentarias significativas por el mitílido Semimytilus algosus. En general, A. monodon bajo condiciones de laboratorio presentó una conducta de forrajeo en la cual maximizó la ganancia neta de energía, mediante la selección de las especies y tamaños de presas que le retribuyen la mayor rentabilidad energéticaWe investigated the ecology and foraging behavior of Acanthina monodon, a muricid gastropod that inhabits in the intertidal rocky shores of central Chile. In the field, we studied temporal variation of their spatial distribution, density, and diet composition. While in the laboratory, we quantified the consumption rate, alimentary preferences, ingestion times and energy profitability obtained with different types of prey using experiments and video recording. High densities of A. monodon individuals were observed in the intertidal fringe near at the

  5. Influence of thermal loading on the ecology of intertidal algae

    International Nuclear Information System (INIS)

    Vadas, R.L.; Keser, M.; Rusanowski, P.c.

    1976-01-01

    Thermal effluents from the Maine Yankee Atomic Power Company (operating intermittently from October 1972 to December 1974) increased water temperatures in the discharge area by 7 to 15 0 C. Plant operation and the removal of a causeway increased mixing and salinities in Montsweag Bay. Four small red algae immigrated into the area, but no species were lost from the system. Distribution and abundance patterns of the dominant algae, Ascophyllum nodosum and Fucus vesiculosus, were altered by the thermal discharge. The cover of F. vesiculosus decreased, whereas that of A. nodosum increased in 1973 but declined significantly in 1974. Reductions in biomass and percent cover were accompanied by changes in the growth dynamics of A. nodosum. Growth and survival in the discharge area were enhanced in 1973 but reduced in 1974. Growth was initiated earlier at all sites affected by the warm water. Plants at experimental sites not directly in the discharge channel grew at accelerated rates during the two years, but stressed plants in the discharge produced few or no viable apexes in 1974. The net effect has been a compression and reduction of intertidal algae into a narrower and less dense band

  6. Distribution of macroinvertebrates on intertidal rocky shores in Gorgona Island, Colombia (Tropical Eastern Pacific

    Directory of Open Access Journals (Sweden)

    Edgardo Londoño-Cruz

    2014-02-01

    Full Text Available Organisms found on rocky shores must endure harsh environmental conditions during tidal changes but scientific studies on tropical rocky shores are scarce, particularly in Colombian shores. Here we describe the spatial distribution of macroinvertebrates associated to the intertidal rocky ecosystems of Gorgona Island, Colombia (Tropical Eastern Pacific. Sampling was carried out in four localities around the Island: La Ventana and La Camaronera (sampled during October 2010 and La Mancora and El Muelle (sampled during March 2011. Two methodologies were used: rapid ecological assessments for qualitative data and quadrats for quantitative data. The richness, abundance, diversity (Shannon-Wiener H’, and evenness (Pielou J’ of macroinvertebrates were determined for and compared between, using one way ANOVA, each locality and the three intertidal zones of La Ventana (see methods. One hundred twenty-one species of macroinvertebrates were found during the sampling period. In all localities, Mollusca was the richest and most abundant taxon (46% of the species and 59% of the individuals, followed by Crustacea (32% of the species and 33% of the individuals. The other groups accounted for the remaining 22% of the richness and 8% of the abundance. Several studies have demonstrated that mollusks and crustaceans are the richest and most abundant taxa in marine benthic communities. Most of the abundant species found were herbivores. The species composition varied among zones. The results of dominant species for each zone are consistent with the ones observed in other tropical rocky intertidal shores. All response variables showed a decreasing pattern from the low to the high intertidal (in La Ventana. Post-hoc results indicated that the high intertidal, the zone with the harshest environmental conditions, had significantly lower values than the other two zones for all response variables. Comparisons between the low intertidal zones of the different localities

  7. Effects of Intertidal Harvest Practices on Levels of Vibrio parahaemolyticus and Vibrio vulnificus Bacteria in Oysters.

    Science.gov (United States)

    Jones, J L; Kinsey, T P; Johnson, L W; Porso, R; Friedman, B; Curtis, M; Wesighan, P; Schuster, R; Bowers, J C

    2016-08-01

    Vibrio parahaemolyticus and Vibrio vulnificus can grow rapidly in shellfish subjected to ambient air conditions, such as during intertidal exposure. In this study, levels of total and pathogenic (tdh(+) and/or trh(+)) V. parahaemolyticus and total V. vulnificus were determined in oysters collected from two study locations where intertidal harvest practices are common. Samples were collected directly off intertidal flats, after exposure (ambient air [Washington State] or refrigerated [New Jersey]), and after reimmersion by natural tidal cycles. Samples were processed using a most-probable-number (MPN) real-time PCR method for total and pathogenic V. parahaemolyticus or V. vulnificus In Washington State, the mean levels of V. parahaemolyticus increased 1.38 log MPN/g following intertidal exposure and dropped 1.41 log MPN/g after reimmersion for 1 day, but the levels were dependent upon the container type utilized. Pathogenic V. parahaemolyticus levels followed a similar trend. However, V. vulnificus levels increased 0.10 log MPN/g during intertidal exposure in Washington but decreased by >1 log MPN/g after reimmersion. In New Jersey, initial levels of all vibrios studied were not significantly altered during the refrigerated sorting and containerizing process. However, there was an increase in levels after the first day of reimmersion by 0.79, 0.72, 0.92, and 0.71 log MPN/g for total, tdh(+) and trh(+) V. parahaemolyticus, and V. vulnificus, respectively. The levels of all targets decreased to those similar to background after a second day of reimmersion. These data indicate that the intertidal harvest and handling practices for oysters that were studied in Washington and New Jersey do not increase the risk of illness from V. parahaemolyticus or V. vulnificus Vibrio parahaemolyticus and Vibrio vulnificus are the leading causes of seafood-associated infectious morbidity and mortality in the United States. Vibrio spp. can grow rapidly in shellfish subjected to ambient

  8. Why do card issuers charge proportional fees?

    OpenAIRE

    Oz Shy; Zhu Wang

    2008-01-01

    This paper explains why payment card companies charge consumers and merchants fees which are proportional to the transaction values instead of charging a fixed per-transaction fee. Our theory shows that, even in the absence of any cost considerations, card companies earn much higher profit when they charge proportional fees. It is also shown that competition among merchants reduces card companies' gains from using proportional fees relative to a fixed per-transaction fee. Merchants are found ...

  9. Relating arithmetical techniques of proportion to geometry

    DEFF Research Database (Denmark)

    Wijayanti, Dyana

    2015-01-01

    The purpose of this study is to investigate how textbooks introduce and treat the theme of proportion in geometry (similarity) and arithmetic (ratio and proportion), and how these themes are linked to each other in the books. To pursue this aim, we use the anthropological theory of the didactic....... Considering 6 common Indonesian textbooks in use, we describe how proportion is explained and appears in examples and exercises, using an explicit reference model of the mathematical organizations of both themes. We also identify how the proportion themes of the geometry and arithmetic domains are linked. Our...

  10. The reproductive cycle of the intertidal gastropod Turbo coronatus ...

    African Journals Online (AJOL)

    Histological methods were used to determine the reproductive cycle of Turbo coronatus. Ovarian development was assessed from the relative proportions of mature and immature oocytes in sectioned material. Testicular tissues ware subjectively given a maturity index based on the relative proportions of the various ...

  11. Gradients of intertidal primary productivity around the coast of South Africa and their relationships with consumer biomass

    CSIR Research Space (South Africa)

    Bustamante, RH

    1995-05-01

    Full Text Available ( r 2 = 0 .580; p<0.01) / . . . . , . . . . i . . . . i . . . . ~ . . . . j . . . . j 10 20 30 40 50 60 Intertidal chlorophyll-a (~tg cm'2 mo "1) Fig. 10 Relationships between the intertidal productivity and a average grazer biomass...

  12. Oblique second-order sand transport pathways on an intertidal sand flat in a natural tidal inlet system

    DEFF Research Database (Denmark)

    Ernstsen, Verner Brandbyge; Lefebvre, Alice; Kroon, Aart

    2013-01-01

    tide, sand is transported along ESE-oriented pathways across the intertidal flat towards the inner tidal basin. During the late stages of ebb tide, sand is transported in drainage channels (WSWoriented) from the intertidal flat towards the inlet channel. During storm events with winds from SW, wave...

  13. Molluscan assemblages of seagrass-covered and bare intertidal flats on the Banc d'Arguin, Mauritania, in relation to characteristics of sediment and organic matter

    NARCIS (Netherlands)

    Honkoop, Pieter J. C.; Berghuis, Eilke M.; Holthuijsen, Sander; Lavaleye, Marc S. S.; Piersma, Theunis

    2008-01-01

    The Banc d'Arguin, a non-estuarine area of shallows and intertidal flats off the tropical Saharan coast of Mauritania, is characterised by extensive intertidal and subtidal seagrass beds. We examined the characteristics of intertidal seagrass (Zostera noltii) meadows and bare areas in terms of the

  14. Proportional Reasoning and the Visually Impaired

    Science.gov (United States)

    Hilton, Geoff; Hilton, Annette; Dole, Shelley L.; Goos, Merrilyn; O'Brien, Mia

    2012-01-01

    Proportional reasoning is an important aspect of formal thinking that is acquired during the developmental years that approximate the middle years of schooling. Students who fail to acquire sound proportional reasoning often experience difficulties in subjects that require quantitative thinking, such as science, technology, engineering, and…

  15. Adaptive bayesian analysis for binomial proportions

    CSIR Research Space (South Africa)

    Das, Sonali

    2008-10-01

    Full Text Available of testing the proportion of some trait. For example, say, we are interested to infer about the effectiveness of a certain intervention teaching strategy, by comparing proportion of ‘proficient’ teachers, before and after an intervention. The number...

  16. Mix Proportion Design of Asphalt Concrete

    Science.gov (United States)

    Wu, Xianhu; Gao, Lingling; Du, Shoujun

    2017-12-01

    Based on the gradation of AC and SMA, this paper designs a new type of anti slide mixture with two types of advantages. Chapter introduces the material selection, ratio of ore mixture ratio design calculation, and determine the optimal asphalt content test and proportioning design of asphalt concrete mix. This paper introduces the new technology of mix proportion.

  17. Dissolved gaseous mercury formation and mercury volatilization in intertidal sediments.

    Science.gov (United States)

    Cesário, Rute; Poissant, Laurier; Pilote, Martin; O'Driscoll, Nelson J; Mota, Ana M; Canário, João

    2017-12-15

    Intertidal sediments of Tagus estuary regularly experiences complex redistribution due to tidal forcing, which affects the cycling of mercury (Hg) between sediments and the water column. This study quantifies total mercury (Hg) and methylmercury (MMHg) concentrations and fluxes in a flooded mudflat as well as the effects on water-level fluctuations on the air-surface exchange of mercury. A fast increase in dissolved Hg and MMHg concentrations was observed in overlying water in the first 10min of inundation and corresponded to a decrease in pore waters, suggesting a rapid export of Hg and MMHg from sediments to the water column. Estimations of daily advective transport exceeded the predicted diffusive fluxes by 5 orders of magnitude. A fast increase in dissolved gaseous mercury (DGM) concentration was also observed in the first 20-30min of inundation (maximum of 40pg L -1 ). Suspended particulate matter (SPM) concentrations were inversely correlated with DGM concentrations. Dissolved Hg variation suggested that biotic DGM production in pore waters is a significant factor in addition to the photochemical reduction of Hg. Mercury volatilization (ranged from 1.1 to 3.3ngm -2 h -1 ; average of 2.1ngm -2 h -1 ) and DGM production exhibited the same pattern with no significant time-lag suggesting a fast release of the produced DGM. These results indicate that Hg sediment/water exchanges in the physical dominated estuaries can be underestimated when the tidal effect is not considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Alkalinity production in intertidal sands intensified by lugworm bioirrigation.

    Science.gov (United States)

    Rao, Alexandra M F; Malkin, Sairah Y; Montserrat, Francesc; Meysman, Filip J R

    2014-07-05

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O 2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO 3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer.

  19. Proportional gas scintillation detectors and their applications

    International Nuclear Information System (INIS)

    Petr, I.

    1978-01-01

    The principle is described of a gas proportional scintillation detector and its function. Dependence of Si(Li) and xenon proportional detectors energy resolution on the input window size is given. A typical design is shown of a xenon detector used for X-ray spetrometry at an energy of 277 eV to 5.898 keV and at a gas pressure of 98 to 270 kPa. Gas proportional scintillation detectors show considerable better energy resolution than common proportional counters and even better resolution than semiconductor Si(Li) detectors for low X radiation energies. For detection areas smaller than 25 mm 2 Si(Li) detectors show better resolution, especially for higher X radiation energies. For window areas 25 to 190 mm 2 both types of detectors are equal, for a window area exceeding 190 mm 2 the proportional scintillation detector has higher energy resolution. (B.S.)

  20. Host-specific phenotypic plasticity of the turtle barnacle Chelonibia testudinaria: a widespread generalist rather than a specialist.

    Directory of Open Access Journals (Sweden)

    Chi Chiu Cheang

    Full Text Available Turtle barnacles are common epibionts on marine organisms. Chelonibia testudinaria is specific on marine turtles whereas C. patula is a host generalist, but rarely found on turtles. It has been questioned why C. patula, being abundant on a variety of live substrata, is almost absent from turtles. We evaluated the genetic (mitochondrial COI, 16S and 12S rRNA, and amplified fragment length polymorphism (AFLP and morphological differentiation of C. testudinaia and C. patula from different hosts, to determine the mode of adaptation exhibited by Chelonibia species on different hosts. The two taxa demonstrate clear differences in shell morphology and length of 4-6(th cirri, but very similar in arthropodal characters. Moreover, we detected no genetic differentiation in mitochondrial DNA and AFLP analyses. Outlier detection infers insignificant selection across loci investigated. Based on combined morphological and molecular evidence, we proposed that C. testudinaria and C. patula are conspecific, and the two morphs with contrasting shell morphologies and cirral length found on different host are predominantly shaped by developmental plasticity in response to environmental setting on different hosts. Chelonibia testudinaria is, thus, a successful general epibiotic fouler and the phenotypic responses postulated can increase the fitness of the animals when they attach on hosts with contrasting life-styles.

  1. A System-Wide Approach to Identify the Mechanisms of Barnacle Attachment: Toward the Discovery of New Antifouling Compounds

    KAUST Repository

    Al-Aqeel, Sarah

    2015-11-01

    Biofouling is a significant economic problem, particularly for marine and offshore oil industries. The acorn barnacle (Amphibalanus (Balanus) amphitrite) is the main biofouling organism in marine environments. Environmental conditions, the physiology of the biofouling organism, the surrounding microbial community, and the properties of the substratum can all influence the attachment of biofouling organisms to substrates. My dissertation investigated the biological processes involved in B. amphitrite development and attachment in the unique environment of the Red Sea, where the average water surface temperature is 34°C and the salinity reaches 41‰. I profiled the transcriptome and proteome of B. amphitrite at different life stages (nauplius II, nauplius VI, and cyprid) and identified 65,784 expressed contigs and 1387 expressed proteins by quantitative proteomics. During the planktonic stage, genes related to osmotic stress, salt stress, the hyperosmotic response, and the Wnt signaling pathway were strongly up-regulated, hereas genes related to the MAPK pathway, lipid metabolism, and cuticle development were down-regulated. In the transition from the nauplius VI to cyprid stages, there was up-regulation of genes involved in blood coagulation, cuticle development, and eggshell formation, and down-regulation of genes in the nitric oxide pathway, which stimulates the swimming and feeding responses of marine invertebrates. This system-wide integrated approach elucidated the development and attachment pathways important in B. amphitrite. Enzymes and metabolites in these pathways are potential molecular targets for the development of new antifouling compounds.

  2. Phylogeography of a Marine Insular Endemic in the Atlantic Macaronesia: The Azorean Barnacle, Megabalanus azoricus (Pilsbry, 1916)

    Science.gov (United States)

    González, José A.; Almeida, Corrine; Lopes, Evandro; Araújo, Ricardo; Carreira, Gilberto P.

    2015-01-01

    The Azorean barnacle, Megabalanus azoricus (Pilsbry, 1916), is a Macaronesian endemic whose obscure taxonomy and the unknown relationships among forms inhabiting isolated Northern Atlantic oceanic islands is investigated by means of molecular analysis herein. Mitochondrial data from the 16S rRNA and COX1 genes support its current species status, tropical ancestry, and the taxonomic homogeneity throughout its distribution range. In contrast, at the intraspecific level and based on control region sequences, we detected an overall low level of genetic diversity and three divergent lineages. The haplogroups α and γ were sampled in the Azores, Madeira, Canary, and Cabo Verde archipelagos; whereas haplogroup β was absent from Cabo Verde. Consequently, population analysis suggested a differentiation of the Cabo Verde population with respect to the genetically homogenous northern archipelagos generated by current oceanographic barriers. Furthermore, haplogroup α, β, and γ demographic expansions occurred during the interglacial periods MIS5 (130 Kya - thousands years ago -), MIS3 (60 Kya), and MIS7 (240 Kya), respectively. The evolutionary origin of these lineages is related to its survival in the stable southern refugia and its demographic expansion dynamics are associated with the glacial-interglacial cycles. This phylogeographic pattern suggests the occurrence of genetic discontinuity informative to the delimitation of an informally defined biogeographic entity, Macaronesia, and its generation by processes that delineate genetic diversity of marine taxa in this area. PMID:25919141

  3. Icon arrays help younger children's proportional reasoning.

    Science.gov (United States)

    Ruggeri, Azzurra; Vagharchakian, Laurianne; Xu, Fei

    2018-06-01

    We investigated the effects of two context variables, presentation format (icon arrays or numerical frequencies) and time limitation (limited or unlimited time), on the proportional reasoning abilities of children aged 7 and 10 years, as well as adults. Participants had to select, between two sets of tokens, the one that offered the highest likelihood of drawing a gold token, that is, the set of elements with the greater proportion of gold tokens. Results show that participants performed better in the unlimited time condition. Moreover, besides a general developmental improvement in accuracy, our results show that younger children performed better when proportions were presented as icon arrays, whereas older children and adults were similarly accurate in the two presentation format conditions. Statement of contribution What is already known on this subject? There is a developmental improvement in proportional reasoning accuracy. Icon arrays facilitate reasoning in adults with low numeracy. What does this study add? Participants were more accurate when they were given more time to make the proportional judgement. Younger children's proportional reasoning was more accurate when they were presented with icon arrays. Proportional reasoning abilities correlate with working memory, approximate number system, and subitizing skills. © 2018 The British Psychological Society.

  4. Count rate effect in proportional counters

    International Nuclear Information System (INIS)

    Bednarek, B.

    1980-01-01

    A critical evaluaton is presented of the actual state of investigations and explanations of the resolution and pulse height changes resulted in proportional counters from radiation intensity variations. (author)

  5. Behavioral and physiological photoresponses to light intensity by intertidal microphytobenthos

    Science.gov (United States)

    Du, Guoying; Yan, Hongmei; Liu, Chunrong; Mao, Yunxiang

    2017-03-01

    Behavioral and physiological responses to light are the two major mechanisms by which natural microphytobenthic assemblages adapt to the intertidal environment and protect themselves from light stress. The present study investigated these photoresponses with different light intensities over 8 h of illumination, and used a specific inhibitor (Latrunculin A, Lat A) for migration to compare migratory and non-migratory microphytobenthos (MPB). Photosynthetic activity was detected using rapid light curves and induction curves by chlorophyll fluorescence. It showed distinct variation in migratory responses to different light intensities; high light induced downward migration to avoid photoinhibition, and low and medium light (50-250 μmol/(m2·s)) promoted upward migration followed by downward migration after certain period of light exposure. No significant difference in non-photochemical quenching (NPQ) or PSII maximal quantum yield (Fv/Fm) was detected between low and medium light irradiance, possibly indicating that only high light influences the photosynthetic capability of MPB. Decreased photosynthetic activity, indicated by three parameters, the maximum relative electron transport rate (rETRmax), minimum saturating irradiance (E k) and light utilization coefficient (α), was observed in MPB after exposure to prolonged illumination under low and medium light. Lat A effectively inhibited the migration of MPB in all light treatments and induced lower Fv/Fmunder high light (500 and 100 μmol/(m2·s)) and prolonged illumination at 250 μmol/(m2·s), but did not significantly influence Fv/Fmunder low light (0-100 μmol/(m2·s)) or NPQ. The increase of NPQ in Lat A treatments with time implied that the MPB assemblages can recover their physiological photoprotection capacity to adapt to light stress. Non-migratory MPB exhibited lower light use efficiency (lower α) and lower maximum photosynthetic capacity (lower rETRmax) than migratory MPB under light intensities above

  6. Unstable Pore-Water Flow in Intertidal Wetlands

    Science.gov (United States)

    Barry, D. A.; Shen, C.; Li, L.

    2014-12-01

    Salt marshes are important intertidal wetlands strongly influenced by interactions between surface water and groundwater. Bordered by coastal water, the marsh system undergoes cycles of inundation and exposure driven by the tide. This leads to dynamic, complex pore-water flow and solute transport in the marsh soil. Pore-water circulations occur over vastly different spatial and temporal scales with strong link to the marsh topography. These circulations control solute transport between the marsh soil and the tidal creek, and ultimately affect the overall nutrient exchange between the marsh and coastal water. The pore-water flows also dictate the soil condition, particularly aeration, which influences the marsh plant growth. Numerous studies have been carried out to examine the pore-water flow process in the marsh soil driven by tides, focusing on stable flow with the assumption of homogeneity in soil and fluid properties. This assumption, however, is questionable given the actual inhomogeneous conditions in the field. For example, the salinity of surface water in the tidal creek varies temporally and spatially due to the influence of rainfall and evapotranspiration as well as the freshwater input from upland areas to the estuary, creating density gradients across the marsh surface and within the marsh soil. Many marshes possess soil stratigraphy with low-permeability mud typically overlying high-permeability sandy deposits. Macropores such as crab burrows are commonly distributed in salt marsh sediments. All these conditions are prone to the development of non-uniform, unstable preferential pore-water flow in the marsh soil, for example, funnelling and fingering. Here we present results from laboratory experiments and numerical simulations to explore such unstable flow. In particular, the analysis aims to address how the unstable flow modifies patterns of local pore-water movement and solute transport, as well as the overall exchange between the marsh soil and

  7. Barnacle cyprid motility and distribution in the water column as an indicator of the settlement-inhibiting potential of nontoxic antifouling chemistries.

    Science.gov (United States)

    Maleschlijski, Stojan; Bauer, Stella; Di Fino, Alessio; Sendra, G Hernan; Clare, Anthony S; Rosenhahn, Axel

    2014-10-01

    Testing of new coatings to control fouling frequently involves single-species laboratory bioassays. Barnacle cyprids are among the most widely used model organisms in marine biofouling research, and surfaces that inhibit their settlement are considered to be promising candidates for new coating concepts. An analysis of motility parameters (mean velocity and swimming area coefficient) and distribution of cyprids of Balanus amphitrite in different swimming regions in the vicinity of model surfaces (self-assembled monolayers) is presented. The data are correlated with the settlement preferences of cyprids on these surfaces. Cyprids were predominantly found in interfacial regions and the transition frequencies between swimming regions of different depths were determined.

  8. Response of deposit-feeders to exclusion of epibenthic predators in a Mediterranean intertidal flat

    NARCIS (Netherlands)

    Como, S.; Rossi, F.; Lardicci, C.

    2004-01-01

    Deposit-feeders are common components of macrofaunal assemblages in intertidal soft sediments. Predation has been considered to have a central role in affecting their distribution and population dynamics. This study investigates the effect of epibenthic predators on deposit-feeders, inhabiting the

  9. Habitat modification drives benthic trophic diversity in an intertidal soft-bottom ecosystem

    NARCIS (Netherlands)

    van der Zee, E.M.; Tielens, E.; Holthuijsen, S.; Donadi, S.; Eriksson, B.K.; van der Veer, H.W.; Piersma, T.; Olff, H.; van der Heide, T.

    2015-01-01

    In intertidal soft-bottom ecosystems, ecosystem engineers such as reef-building bivalves, can strongly affect the associated benthic community by providing structure and stabilizing the sediment. Although several engineering species have declined dramatically in the past centuries, the consequences

  10. Cross-habitat interactions among bivalve species control community structure on intertidal flats

    NARCIS (Netherlands)

    Donadi, S.; van der Heide, T.; van der Zee, E.M.; Eklöf, J.S.; van de Koppel, J.; Weerman, E.J.; Piersma, T.; Olff, H.; Eriksson, B.K.

    2013-01-01

    Increasing evidence shows that spatial interactions between sedentary organisms can structure communities and promote landscape complexity in many ecosystems. Here we tested the hypothesis that reef-forming mussels (Mytilus edulis L.), a dominant intertidal ecosystem engineer in the Wadden Sea,

  11. Cross-habitat interactions among bivalve species control community structure on intertidal flats

    NARCIS (Netherlands)

    Donadi, Serena; van der Heide, Tjisse; van der Zee, Els M.; Eklöf, Johan S.; van de Koppel, Johan; Weerman, Ellen J.; Piersma, Theunis; Olff, Han; Eriksson, Britas Klemens

    Increasing evidence shows that spatial interactions between sedentary organisms can structure communities and promote landscape complexity in many ecosystems. Here we tested the hypothesis that reef-forming mussels (Mytilus edulis L.), a dominant intertidal ecosystem engineer in the Wadden Sea,

  12. Composition, diversity and distribution of microbenthos across the intertidal zones of Ryazhkov Island (the White Sea).

    Science.gov (United States)

    Azovsky, Andrey; Saburova, Maria; Tikhonenkov, Denis; Khazanova, Ksenya; Esaulov, Anton; Mazei, Yuri

    2013-11-01

    The composition and distribution of the main unicellular eukaryotic groups (diatom algae, ciliates, dinoflagellates (DF), other phototrophic (PF) and heterotrophic flagellates (HF)) were investigated in sandy sediments at five stations allocated across the tidal sheltered beach of the White Sea. Overall, 75 diatoms, 98 ciliates, 16 DF, 3 PF and 34 HF species were identified; some are new records for the White Sea. Common species for each group are illustrated. Diatoms and ciliates showed high alpha-diversity (species richness per sample), whereas flagellates were characterized by high beta-diversity (species turnover across the intertidal flat). Each group demonstrated its own spatial pattern that was best matched with its own subset of abiotic variables, reflecting group-specific responses to environmental gradients. Species richness increased from the upper intertidal zone seaward for ciliates but decreased for HF, whereas autotrophs showed a relatively uniform pattern with a slight peak at the mid-intertidal zone. Across the littoral zone, all groups showed distinct compositional changes; however, the position of the boundary between "upper" and "lower" intertidal communities varied among groups. Most of the species found at Ryazhkov Island are known from many other regions worldwide, indicating a wide geographic distribution of microbial eukaryotic species. Copyright © 2013 Elsevier GmbH. All rights reserved.

  13. The potential of aerial photography for estimating surface areas of intertidal Pacific oyster beds (Crassostrea gigas)

    NARCIS (Netherlands)

    Kater, B.J.; Baars, J.M.D.D.

    2004-01-01

    Pacific oysters were introduced into the Eastern Scheldt in 1964 for breeding purposes. The first spatfall of wild Pacific oysters was recorded in 1976, and a second larval outburst in 1982 definitely settled wild Pacific oysters in the Eastern Scheldt waters. Oyster beds on intertidal and subtidal

  14. Identifying knowledge gaps hampering application of intertidal habitats in coastal protection: Opportunities & steps to take

    NARCIS (Netherlands)

    Bouma, T.J.; van Belzen, J.; Balke, T.; Zhu, Z.; Airoldi, L.; Blight, A.J.; Davies, A.J.; Galván, C.; Hawkins, S.J.; Hoggart, S.P.G.; Lara, J.L.; Losada, I.J.; Maza, M.; Ondiviela, B.; Skov, M.W.; Strain, E.M.; Thompson, R.C.; Yang, S.L.; Zanuttigh, B.; Zhang, L.; Herman, P.M.J.

    2014-01-01

    Over the last decades, population densities in coastal areas have strongly increased. At the same time, many intertidal coastal ecosystems that provide valuable services in terms of coastal protection have greatly degraded. As a result, coastal defense has become increasingly dependent on man-made

  15. Spatial self-organized patterning in seagrasses along a depth gradient of an intertidal ecosystem

    NARCIS (Netherlands)

    van der Heide, Tjisse; Bouma, Tjeerd J.; Nes, Egbert H. van; van de Koppel, Johan; Scheffer, Marten; Roelofs, Jan G.M.; Katwijk, Marieke M. van; Smolders, Alfons J.P.

    2010-01-01

    The spatial structure of seagrass landscapes is typically ascribed to the direct influence of physical factors such as hydrodynamics, light, and sediment transport. We studied regularly interspaced banded patterns, formed by elongated patches of seagrass, in a small-scale intertidal ecosystem. We

  16. Sediment characteristics at intertidal regions across Yarada beach, East coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Yadhunath, E.M.; Raju, N.S.N.; Ganesan, P.; Gowthaman, R.; JayaKumar, S.

    Sediment samples were collected once a month at five different inter-tidal zones across Yarada beach during May-2009 to May-2010 These sediments are characterized by bimodal and unimodal behaviour and most of them are sorted as moderately as well...

  17. Low-Cost Ultra-High Spatial and Temporal Resolution Mapping of Intertidal Rock Platforms

    Science.gov (United States)

    Bryson, M.; Johnson-Roberson, M.; Murphy, R.

    2012-07-01

    Intertidal ecosystems have primarily been studied using field-based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time which could compliment field-based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging) provide data at relatively course, sub-meter resolutions or with limited temporal resolutions and relatively high costs for small-scale environmental science and ecology studies. In this paper, we describe a low-cost, kite-based imaging system and photogrammetric pipeline that was developed for constructing highresolution, 3D, photo-realistic terrain models of intertidal rocky shores. The processing pipeline uses automatic image feature detection and matching, structure-from-motion and photo-textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer-grade digital cameras. The resulting maps combine colour and topographic information at sub-centimeter resolutions over an area of approximately 100m, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rock platform at Cape Banks, Sydney, Australia. Potential uses of this technique include mapping of plant (micro- and macro-algae) and animal (e.g. gastropods) assemblages at multiple spatial and temporal scales.

  18. Microscale spatio-temporal patterns of oxygen dynamics in permeable intertidal sediments (Skallingen, Denmark)

    DEFF Research Database (Denmark)

    Walpersdorf, Eva Christine; Andersen, Thorbjørn Joest; Elberling, Bo

     Intertidal permeable sediments are, even more than subtidal sediments (Cook et al. 2007), subject to extreme dynamics due to fast changing environ-mental conditions during inundation and emergence. In such systems, a quasi steady state is rarely reached. Integrative in-situ studies covering...

  19. Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence

    NARCIS (Netherlands)

    Kromkamp, J.C.; Morris, E.P.; Forster, R.M.; Honeywill, C.; Hagerthey, S.; Paterson, D.M.

    2006-01-01

    Estimating biomass of microphytobenthos (MPB) on intertidal mud flats is extremely difficult due to their patchy occurrence, especially at the scale of an entire mud flat. We tested two optical approaches that can be applied in situ: spectral reflectance and chlorophyll fluorescence. These two

  20. The exploitation of intertidal food resources in Inhaca bay, Mozambique, by shorebirds and humans

    NARCIS (Netherlands)

    Boer, de W.F.; Longamane, F.A.

    1996-01-01

    The intertidal areas on Inhaca island provide important food resources for shorebirds as well as the local population. Average bird density is 2-6 individuals/ha during summer, decreasing to 0.3 in winter, which is one of the lowest records for the African coasts. Whimbrels Numenius phaeopus and

  1. Intertidal benthic community ecology of sand-dwelling macroinvertebrates of Goa beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Parulekar, A.H.

    Studies on the intertidal ecology of two sandy beaches of Goa along the western coast of India revealed the presence of 47 species of macroinvertebrates belonging to 32 families. The open beach at Candolim, characterized by coarse sand-grain size...

  2. Distribution and biomass estimation of shell-boring algae in the intertidal area at Goa India

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Sharma, S.; Lande, V.

    The distribution and frequency of shell-boring green and blue-green algae in the intertidal at Goa, India were studied. The green alga Gomontia sp. and the blue green algae Hyella caespitosa Bornet et Flahault, H. gigas Lucas et Golubic...

  3. Flexibility of Physiological Traits Underlying Inter-Individual Growth Differences in Intertidal and Subtidal Mussels Mytilusgalloprovincialis.

    Directory of Open Access Journals (Sweden)

    María José Fernández-Reiriz

    Full Text Available Mussel seed (Mytilusgalloprovincialis gathered from the intertidal and subtidal environments of a Galician embayment (NW, Spain were maintained in the laboratory during five months to select fast (F and slow (S growing mussels. The physiological basis underlying inter-individual growth variations were compared for F and S mussels from both origins. Fast growing seemed to be a consequence of greater energy intake (20% higher clearance and ingestion rate and higher food absorption rate coupled with low metabolic costs. The enhanced energy absorption (around 65% higher resulted in 3 times higher Scope for Growth in F mussels (20.5±4.9 J h(-1 than S individuals (7.3±1.1 J h(-1. The higher clearance rate of F mussels appears to be linked with larger gill filtration surface compared to S mussels. Intertidal mussels showed higher food acquisition and absorption per mg of organic weight (i.e. mass-specific standardization than subtidal mussels under the optimal feeding conditions of the laboratory. However, the enhanced feeding and digestive rates were not enough to compensate for the initial differences in tissue weight between mussels of similar shell length collected from the intertidal and subtidal environments. At the end of the experiment, subtidal individuals had higher gill efficiency, which probably lead to higher total feeding and absorption rates relative to intertidal individuals.

  4. Role of salinity in structuring the intertidal meiofauna of a tropical estuarine beach: Field evidence

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Parulekar, A.H.

    Community structure of meiofauna was studied for 12 months (July 1991-June 1992) on an estuarine intertidal beach at Siridao, Goa (India). The temperature of the surf zone water ranged from 26.5 degrees to 30.7 degrees C; salinity from 8.3 to 34.4 x...

  5. DOCUMENTING THE INTERTIDAL COMPONENT OF EELGRASS DISTRIBUTIONS IN PACIFIC NORTHWEST ESTUARIES USING COLOR INFRARED AERIAL PHOTOGRAPHY

    Science.gov (United States)

    The objective of this study was to develop and test a rapid, cost-effective method of mapping the intertidal (and surface-visible subtidal) distribution of eelgrass (Zostera marina L.) meadows and patches in the turbid coastal estuaries of the Pacific Northwest (PNW). Initial co...

  6. Production by intertidal benthic animals and limits to their predation by shorebirds : a heuristic model

    NARCIS (Netherlands)

    Piersma, Theunis

    1987-01-01

    This review examines the question whether the cumulative amount of benthic biomass removed by feeding shorebirds on a certain intertidal area is limited by the renewal rate of benthic food stocks. Limitations of current methods to estimate both predatory impact by shorebirds and harvestable benthic

  7. Plutonium transport to and deposition and immobility in Irish Sea intertidal sediments

    Energy Technology Data Exchange (ETDEWEB)

    Aston, S R; Stanners, D A [Lancaster Univ. (UK)

    1981-02-12

    The results are presented of an investigation of plutonium in intertidal sediments of the Irish Sea, contaminated with radioactive wastes from the Windscale reprocessing facility. The deposition characteristics and lack of vertical migration of /sup 238/Pu and /sup 239/ and /sup 240/Pu are discussed.

  8. Proportion congruency effects: Instructions may be enough

    Directory of Open Access Journals (Sweden)

    Olga eEntel

    2014-10-01

    Full Text Available Learning takes time, namely, one needs to be exposed to contingency relations between stimulus dimensions in order to learn, whereas intentional control can be recruited through task demands. Therefore showing that control can be recruited as a function of experimental instructions alone, that is, adapting the processing according to the instructions before the exposure to the task, can be taken as evidence for existence of control recruitment in the absence of learning. This was done by manipulating the information given at the outset of the experiment. In the first experiment, we manipulated list-level congruency proportion. Half of the participants were informed that most of the stimuli would be congruent, whereas the other half were informed that most of the stimuli would be incongruent. This held true for the stimuli in the second part of each experiment. In the first part, however, the proportion of the two stimulus types was equal. A proportion congruent effect was found in both parts of the experiment, but it was larger in the second part. In our second experiment, we manipulated the proportion of the stimuli within participants by applying an item-specific design. This was done by presenting some color words most often in their congruent color, and other color words in incongruent colors. Participants were informed about the exact word-color pairings in advance. Similar to Experiment 1, this held true only for the second experimental part. In contrast to our first experiment, informing participants in advance did not result in an item-specific proportion effect, which was observed only in the second part. Thus our results support the hypothesis that instructions may be enough to trigger list-level control, yet learning does contribute to the proportion congruent effect under such conditions. The item-level proportion effect is apparently caused by learning or at least it is moderated by it.

  9. Cleft, crevice, or the inner thigh: 'another place' for the establishment of the invasive barnacle Austrominius modestus (Darwin, 1854.

    Directory of Open Access Journals (Sweden)

    Sally A Bracewell

    Full Text Available The proliferation of anthropogenic infrastructure in the marine environment has aided the establishment and spread of invasive species. These structures can create novel habitats in areas normally characterised as void of suitable settlement sites. The habitat requirements of the invasive acorn barnacle Austrominius modestus (Darwin, 1854 were assessed using a novel sampling site at Crosby Beach, Liverpool. Austrominius modestus has spread rapidly around the UK since its initial introduction, becoming locally dominant in many estuarine areas including the Antony Gormley art installation, 'Another Place', at Crosby Beach. The installation consists of 100 replicate solid cast-iron life-size human figures, located at a range of heights on the shore. We recorded the distribution and abundance of A. modestus present on all of the statues at various positions during the summer of 2006. The positions varied in location, exposure, direction, and rugosity. Although parameters such as rugosity and exposure did influence patterns of recruitment, they were less important than interactions between shore height and direction, and specific location on the beach. The addition of a suitable substrate to a sheltered and estuarine region of Liverpool Bay has facilitated the establishment of A. modestus. Understanding the habitat requirements of invasive species is important if we are to make predictions about their spread and the likelihood of invasion success. Austrominius modestus has already become locally dominant in some regions of the UK and, with projections of favourable warming conditions and the global expansion of artificial structures, the continued spread of this species can be expected. The implications of this on the balance between native and invasive species dominance should be considered.

  10. Increasing sea surface temperature and range shifts of intertidal gastropods along the Iberian Peninsula

    Science.gov (United States)

    Rubal, Marcos; Veiga, Puri; Cacabelos, Eva; Moreira, Juan; Sousa-Pinto, Isabel

    2013-03-01

    There are well-documented changes in abundance and geographical range of intertidal invertebrates related to climate change at north Europe. However, the effect of sea surface warming on intertidal invertebrates has been poorly studied at lower latitudes. Here we analyze potential changes in the abundance patterns and distribution range of rocky intertidal gastropods related to climate change along the Iberian Peninsula. To achieve this aim, the spatial distribution and range of sub-tropical, warm- and cold-water species of intertidal gastropods was explored by a fully hierarchical sampling design considering four different spatial scales, i.e. from region (100 s of km apart) to quadrats (ms apart). Variability on their patterns of abundance was explored by analysis of variance, changes on their distribution ranges were detected by comparing with previous records and their relationship with sea water temperature was explored by rank correlation analyses. Mean values of sea surface temperature along the Iberian coast, between 1949 and 2010, were obtained from in situ data compiled for three different grid squares: south Portugal, north Portugal, and Galicia. Lusitanian species did not show significant correlation with sea water temperature or changes on their distributional range or abundance, along the temperature gradient considered. The sub-tropical species Siphonaria pectinata has, however, increased its distribution range while boreal cold-water species showed the opposite pattern. The latter was more evident for Littorina littorea that was almost absent from the studied rocky shores of the Iberian Peninsula. Sub-tropical and boreal species showed significant but opposite correlation with sea water temperature. We hypothesized that the energetic cost of frequent exposures to sub-lethal temperatures might be responsible for these shifts. Therefore, intertidal gastropods at the Atlantic Iberian Peninsula coast are responding to the effect of global warming as it

  11. Multiscale patterns in the diversity and organization of benthic intertidal fauna among French Atlantic estuaries

    Science.gov (United States)

    Blanchet, Hugues; Gouillieux, Benoît; Alizier, Sandrine; Amouroux, Jean-Michel; Bachelet, Guy; Barillé, Anne-Laure; Dauvin, Jean-Claude; de Montaudouin, Xavier; Derolez, Valérie; Desroy, Nicolas; Grall, Jacques; Grémare, Antoine; Hacquebart, Pascal; Jourde, Jérôme; Labrune, Céline; Lavesque, Nicolas; Meirland, Alain; Nebout, Thiebaut; Olivier, Frédéric; Pelaprat, Corine; Ruellet, Thierry; Sauriau, Pierre-Guy; Thorin, Sébastien

    2014-07-01

    Based on a parallel sampling conducted during autumn 2008, a comparative study of the intertidal benthic macrofauna among 10 estuarine systems located along the Channel and Atlantic coasts of France was performed in order to assess the level of fauna similarity among these sites and to identify possible environmental factors involved in the observed pattern at both large (among sites) and smaller (benthic assemblages) scales. More precisely this study focused on unraveling the observed pattern of intertidal benthic fauna composition and diversity observed at among-site scale by exploring both biotic and abiotic factors acting at the among- and within-site scales. Results showed a limited level of similarity at the among-site level in terms of intertidal benthic fauna composition and diversity. The observed pattern did not fit with existing transitional water classification methods based on fish or benthic assemblages developed in the frame of the European Water Framework Directive (WFD). More particularly, the coastal plain estuaries displayed higher among-site similarity compared to ria systems. These coastal plain estuaries were characterized by higher influence of river discharge, lower communication with the ocean and high suspended particulate matter levels. On the other hand, the ria-type systems were more dissimilar and different from the coastal plain estuaries. The level of similarity among estuaries was mainly linked to the relative extent of the intertidal "Scrobicularia plana-Cerastoderma edule" and "Tellina tenuis" or "Venus" communities as a possible consequence of salinity regime, suspended matter concentrations and fine particles supply with consequences on the trophic functioning, structure and organization of benthic fauna. Despite biogeographical patterns, the results also suggest that, in the context of the WFD, these estuaries should only be compared on the basis of the most common intertidal habitat occurring throughout all estuarine systems

  12. Proportional hazards models of infrastructure system recovery

    International Nuclear Information System (INIS)

    Barker, Kash; Baroud, Hiba

    2014-01-01

    As emphasis is being placed on a system's ability to withstand and to recover from a disruptive event, collectively referred to as dynamic resilience, there exists a need to quantify a system's ability to bounce back after a disruptive event. This work applies a statistical technique from biostatistics, the proportional hazards model, to describe (i) the instantaneous rate of recovery of an infrastructure system and (ii) the likelihood that recovery occurs prior to a given point in time. A major benefit of the proportional hazards model is its ability to describe a recovery event as a function of time as well as covariates describing the infrastructure system or disruptive event, among others, which can also vary with time. The proportional hazards approach is illustrated with a publicly available electric power outage data set

  13. The Origins of Scintillator Non-Proportionality

    Science.gov (United States)

    Moses, W. W.; Bizarri, G. A.; Williams, R. T.; Payne, S. A.; Vasil'ev, A. N.; Singh, J.; Li, Q.; Grim, J. Q.; Choong, W.-S.

    2012-10-01

    Recent years have seen significant advances in both theoretically understanding and mathematically modeling the underlying causes of scintillator non-proportionality. The core cause is that the interaction of radiation with matter invariably leads to a non-uniform ionization density in the scintillator, coupled with the fact that the light yield depends on the ionization density. The mechanisms that lead to the luminescence dependence on ionization density are incompletely understood, but several important features have been identified, notably Auger-like processes (where two carriers of excitation interact with each other, causing one to de-excite non-radiatively), the inability of excitation carriers to recombine (caused either by trapping or physical separation), and the carrier mobility. This paper reviews the present understanding of the fundamental origins of scintillator non-proportionality, specifically the various theories that have been used to explain non-proportionality.

  14. Large-Scale Analysis of Art Proportions

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2014-01-01

    While literature often tries to impute mathematical constants into art, this large-scale study (11 databases of paintings and photos, around 200.000 items) shows a different truth. The analysis, consisting of the width/height proportions, shows a value of rarely if ever one (square) and with majo......While literature often tries to impute mathematical constants into art, this large-scale study (11 databases of paintings and photos, around 200.000 items) shows a different truth. The analysis, consisting of the width/height proportions, shows a value of rarely if ever one (square...

  15. Temporal assemblage turnovers of intertidal foraminiferal communities from tropical (SE Caribbean) and temperate (NE England and SW Spain) regions

    Science.gov (United States)

    Costelloe, Ashleigh; Wilson, Brent; Horton, Benjamin P.; Hayek, Lee-Ann C.

    2018-05-01

    This is the first quantitative study of temporal assemblage turnovers of the relationships between intertidal foraminifera. Time series datasets collected from tropical Caroni Swamp and Claxton Bay (Trinidad, SE Caribbean) and temperate Cowpen Marsh (NE England, U.K.) and Bay of Cadiz (SW Spain) were used. The assemblage turnover index (ATI) examined species interrelationships through comparisons of monthly or biweekly species proportional abundances over one or two years. Species contributing to major assemblage turnovers (ATI > x + σ) were identified using the conditioned on-boundary index (CoBI). Foraminiferal species are heterogeneously distributed within the sediment; multiple sample stations at a study location cumulatively represent the foraminiferal metacommunity and clusters represent foraminiferal assemblages. The ATI and CoBI were applied to the proportional abundances of live specimens recorded for the metacommunity and assemblages at each location. At Caroni Swamp and Claxton Bay, major assemblage turnovers were driven by the most abundant species and the majority coincided with seasonal change or the arrival of the seasonal Orinoco plume in the Gulf of Paria. Seasonal turnovers of the foraminiferal metacommunities at temperate Cowpen Marsh and Bay of Cádiz occurred during the summer and winter. Major assemblage turnovers in the upper Cowpen Marsh occurred in the summer, and the lower marsh in the winter. Foraminiferans are useful bioindicators for monitoring the health of coastal environments. Understanding foraminiferal population dynamics will allow cyclical changes to be differentiated from abrupt and persistent changes, which are related to anthropogenic disturbances or long-term climate change. The ATI and CoBI are useful indices for quantitatively exploring relationships of foraminiferal populations over time.

  16. Investigation of a multiwire proportional chamber

    International Nuclear Information System (INIS)

    Konijn, J.

    1976-01-01

    The article discusses some aspects of a prototype multiwire proportional chamber for electron detection located at IKO in Amsterdam, i.e. voltage, counting rates, noise and gas mixture (argon, ethylene bromide). The efficiency and performance of the chamber have been investigated and an error analysis is given

  17. Author: IM Rautenbach PROPORTIONALITY AND THE LIMITATION ...

    African Journals Online (AJOL)

    10332324

    public law, it is not clear to me that there are any differences at this more abstract ... Bills of Rights entrench "basic principles of rationality and proportionality – of ..... Sweet Europe of Rights 10-11; Van Dijk and Van Hoof Theory and Practice.

  18. Obtaining a Proportional Allocation by Deleting Items

    NARCIS (Netherlands)

    Dorn, B.; de Haan, R.; Schlotter, I.; Röthe, J.

    2017-01-01

    We consider the following control problem on fair allocation of indivisible goods. Given a set I of items and a set of agents, each having strict linear preference over the items, we ask for a minimum subset of the items whose deletion guarantees the existence of a proportional allocation in the

  19. Proportional green time scheduling for traffic lights

    NARCIS (Netherlands)

    P. Kovacs; Le, T. (Tung); R. Núñez Queija (Rudesindo); Vu, H. (Hai); N. Walton

    2016-01-01

    textabstractWe consider the decentralized scheduling of a large number of urban traffic lights. We investigate factors determining system performance, in particular, the length of the traffic light cycle and the proportion of green time allocated to each junction. We study the effect of the length

  20. Triangular tube proportional wire chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Badtke, D H; Bakken, J A; Barnett, B A; Blumenfeld, B J; Chien, C Y; Madansky, L; Matthews, J A.J.; Pevsner, A; Spangler, W J [Johns Hopkins Univ., Baltimore, MD (USA); Lee, K L [California Univ., Berkeley (USA). Lawrence Berkeley Lab.

    1981-10-15

    We report on the characteristics of the proportional tube chamber system which has been constructed for muon identification in the PEP-4 experiment at SLAC. The mechanical and electrical properties of the extruded aluminum triangular tubes allow these detectors to be used as crude drift chambers.

  1. Commanding to 'Nudge' via the Proportionality Principle?

    NARCIS (Netherlands)

    K.P. Purnhagen (Kai); E. van Kleef (Ellen)

    2017-01-01

    textabstractThis piece assesses whether nudging techniques can be argued to be a less restrictive but equally effective way to regulate diets in EU law. It has been argued that nudging techniques, due to their freedom-preserving nature, might influence the proportionality test in such a way that

  2. The whale barnacle Cryptolepas rhachianecti (Cirripedia: Coronulidae), a phoront of the grey whale Eschrichtius robustus (Cetacea: Eschrichtiidae), from a sandy beach in The Netherlands.

    Science.gov (United States)

    Bosselaers, Mark; Collareta, Alberto

    2016-08-22

    An isolated compartment of a whale barnacle is herein described from Recent beach deposits in Zoutelande (Walcheren, The Netherlands). This specimen is identified as belonging to the extant coronulid species Cryptolepas rhachianecti, currently known as an epizoic symbiont of the grey whale Eschrichtius robustus. This find represents the first occurrence of C. rhachianecti outside the North Pacific, and the first one as a (sub)fossil. In view of the fact that E. robustus, which is currently confined to the North Pacific, is known as a subfossil from the northeastern Atlantic between late Late Pleistocene (c. 45,000 years ago) and historical (c. 1700 AD) times, we propose a similar (late Quaternary) age for the isolated compartment. The find indicates that the extinct late Quaternary northeastern Atlantic population of E. robustus was infected by Cryptolepas rhachianecti. Our find is, therefore, compatible with the hypothesis of an ancient grey whale migration route running between the subtropical/temperate waters of the northeast Atlantic (or Mediterranean Basin), and the cold waters of the Baltic Sea (or southern Arctic Ocean), through the southern North Sea. Finally, we discuss the systematic placement of the fossil barnacle species Cryptolepas murata and propose the possibility of its removal from the genus Cryptolepas pending further investigations.

  3. Diatoms of the microphytobenthic community in a tropical intertidal sand flat influenced by monsoons: Spatial and temporal variations

    Digital Repository Service at National Institute of Oceanography (India)

    Mitbavkar, S.; Anil, A.C.

    to the carbon budgets of such unstable habitats. Introduction Intertidal areas are highly dynamic systems which are constantly influenced by local energy levels and, espe- cially in the case of high energy sand flat areas, exhibit a microstructure governed...

  4. Impact of sewage on the distribution, abundance and community structure of rocky intertidal macroalgae of the Colaba Coast, Mumbai, India

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Komarpant, D.S.

    algae from the Istrian coast (vicinity of Rovinj) Ada Adriatica, 23:329 - 337. Murray, S. N. and M.M. Littler 1984. Analysis of seaweed communities in a disturbed rocky intertidal environment near Whites Point, Los Angeles. California, USA...

  5. Vertical migratory rhythms of benthic diatoms in a tropical intertidal sand flat: Influence of irradiance and tides

    Digital Repository Service at National Institute of Oceanography (India)

    Mitbavkar, S.; Anil, A.C.

    Vertical migratory behavior of benthic diatoms is one of the adaptive strategies employed for a life in intertidal habitats. Irradiance and tides are considered to be the key factors governing vertical migration. Experiments were carried out...

  6. LC/IRMS analysis: A powerful technique to trace carbon flow in microphytobenthic communities in intertidal sediments

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Stal, L.J.; Boschker, H.T.S.

    2014-01-01

    Microphytobenthic communities are important for primary production in intertidal marine sediments. Extracellular polymeric substances (EPS), comprising polysaccharides and proteins, play a key role in the structure and functioning of microphytobenthic biofilms and allow interactions between the

  7. Population characteristics of the mole crab, Hippa adactyla Fabricius, in the intertidal sediment at Kavaratti Atoll, Lakshadweep Islands

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Sreepada, R.A.; Ansari, Z.A.; Parulekar, A.H.

    Some population characteristics of a little known mole crab Hippa adactyla from the sandy intertidal habitat of Kavaratti atoll, Lakshadweep islands, were studied for understanding the resource potentials besides some features of breeding behavior...

  8. Multistate cohort models with proportional transfer rates

    DEFF Research Database (Denmark)

    Schoen, Robert; Canudas-Romo, Vladimir

    2006-01-01

    of transfer rates. The two living state case and hierarchical multistate models with any number of living states are analyzed in detail. Applying our approach to 1997 U.S. fertility data, we find that observed rates of parity progression are roughly proportional over age. Our proportional transfer rate...... approach provides trajectories by parity state and facilitates analyses of the implications of changes in parity rate levels and patterns. More women complete childbearing at parity 2 than at any other parity, and parity 2 would be the modal parity in models with total fertility rates (TFRs) of 1.40 to 2......We present a new, broadly applicable approach to summarizing the behavior of a cohort as it moves through a variety of statuses (or states). The approach is based on the assumption that all rates of transfer maintain a constant ratio to one another over age. We present closed-form expressions...

  9. Pulse triggering mechanism of air proportional counters

    International Nuclear Information System (INIS)

    Aoyama, T.; Mori, T.; Watanabe, T.

    1983-01-01

    This paper describes the pulse triggering mechanism of a cylindrical proportional counter filled with air at atmospheric pressure for the incidence of β-rays. Experimental results indicate that primary electrons created distantly from the anode wire by a β-ray are transformed into negative ions, which then detach electrons close to the anode wire and generate electron avalanches thus triggering pulses, while electrons created near the anode wire by a β-ray directly trigger a pulse. Since a negative ion pulse is triggered by a single electron detached from a negative ion, multiple pulses are generated by a large number of ions produced by the incidence of a single β-ray. It is therefore necessary not to count pulses triggered by negative ions but to count those by primary electrons alone when use is made of air proportional counters for the detection of β-rays. (orig.)

  10. Very large area multiwire spectroscopic proportional counters

    International Nuclear Information System (INIS)

    Ubertini, P.; Bazzano, A.; Boccaccini, L.; Mastropietro, M.; La Padula, C.D.; Patriarca, R.; Polcaro, V.F.

    1981-01-01

    As a result of a five year development program, a final prototype of a Very Large Area Spectroscopic Proportional Counter (VLASPC), to be employed in space borne payloads, was produced at the Istituto di Astrofisica Spaziale, Frascati. The instrument is the last version of a new generation of Multiwire Spectroscopic Proportional Counters (MWSPC) succesfully employed in many balloon borne flights, devoted to hard X-ray astronomy. The sensitive area of this standard unit is 2700 cm 2 with an efficiency higher than 10% in the range 15-180 keV (80% at 60 keV). The low cost and weight make this new type of VLASPC competitive with Nal arrays, phoswich and GSPC detectors in terms of achievable scientific results. (orig.)

  11. Very large area multiwire spectroscopic proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Ubertini, P.; Bazzano, A.; Boccaccini, L.; Mastropietro, M.; La Padula, C.D.; Patriarca, R.; Polcaro, V.F. (Istituto di Astrofisica Spaziale, Frascati (Italy))

    1981-07-01

    As a result of a five year development program, a final prototype of a Very Large Area Spectroscopic Proportional Counter (VLASPC), to be employed in space borne payloads, was produced at the Istituto di Astrofisica Spaziale, Frascati. The instrument is the last version of a new generation of Multiwire Spectroscopic Proportional Counters (MWSPC) successfully employed in many balloon borne flights, devoted to hard X-ray astronomy. The sensitive area of this standard unit is 2700 cm/sup 2/ with an efficiency higher than 10% in the range 15-180 keV (80% at 60 keV). The low cost and weight make this new type of VLASPC competitive with Nal arrays, phoswich and GSPC detectors in terms of achievable scientific results.

  12. Cylindrical geometry for proportional and drift chambers

    International Nuclear Information System (INIS)

    Sadoulet, B.

    1975-06-01

    For experiments performed around storage rings such as e + e - rings or the ISR pp rings, cylindrical wire chambers are very attractive. They surround the beam pipe completely without any dead region in the azimuth, and fit well with the geometry of events where particles are more or less spherically produced. Unfortunately, cylindrical proportional or drift chambers are difficult to make. Problems are discussed and two approaches to fabricating the cathodes are discussed. (WHK)

  13. 2 π gaseous flux proportional detector

    International Nuclear Information System (INIS)

    Guevara, E.A.; Costello, E.D.; Di Carlo, R.O.

    1986-01-01

    A counting system has been developed in order to measure carbon-14 samples obtained in the course of a study of a plasmapheresis treatment for diabetic children. The system is based on the use of a 2π gaseous flux proportional detector especially designed for the stated purpose. The detector is described and experiment results are given, determining the characteristic parameters which set up the working conditions. (Author) [es

  14. General methods for analyzing bounded proportion data

    OpenAIRE

    Hossain, Abu

    2017-01-01

    This thesis introduces two general classes of models for analyzing proportion response variable when the response variable Y can take values between zero and one, inclusive of zero and/or one. The models are inflated GAMLSS model and generalized Tobit GAMLSS model. The inflated GAMLSS model extends the flexibility of beta inflated models by allowing the distribution on (0,1) of the continuous component of the dependent variable to come from any explicit or transformed (i.e. logit or truncated...

  15. Commanding to 'Nudge' via the Proportionality Principle?

    OpenAIRE

    Purnhagen, Kai; van Kleef, Ellen

    2017-01-01

    textabstractThis piece assesses whether nudging techniques can be argued to be a less restrictive but equally effective way to regulate diets in EU law. It has been argued that nudging techniques, due to their freedom-preserving nature, might influence the proportionality test in such a way that authorities need to give preference to nudging techniques over content-related or information regulation. We will illustrate on the example of EU food law how behavioural sciences have first altered t...

  16. Contingency proportion systematically influences contingency learning.

    Science.gov (United States)

    Forrin, Noah D; MacLeod, Colin M

    2018-01-01

    In the color-word contingency learning paradigm, each word appears more often in one color (high contingency) than in the other colors (low contingency). Shortly after beginning the task, color identification responses become faster on the high-contingency trials than on the low-contingency trials-the contingency learning effect. Across five groups, we varied the high-contingency proportion in 10% steps, from 80% to 40%. The size of the contingency learning effect was positively related to high-contingency proportion, with the effect disappearing when high contingency was reduced to 40%. At the two highest contingency proportions, the magnitude of the effect increased over trials, the pattern suggesting that there was an increasing cost for the low-contingency trials rather than an increasing benefit for the high-contingency trials. Overall, the results fit a modified version of Schmidt's (2013, Acta Psychologica, 142, 119-126) parallel episodic processing account in which prior trial instances are routinely retrieved from memory and influence current trial performance.

  17. Spatial and temporal patterns of benthic invertebrates in the Tagus estuary, Portugal: comparison between subtidal and an intertidal mudflat

    Directory of Open Access Journals (Sweden)

    Susana França

    2009-06-01

    Full Text Available Intertidal mudflats are a dominant feature in many estuarine systems and may be a significant component of the feeding grounds available for many fish and bird species. Therefore, it is crucial to determine the importance and role that this particular habitat plays for the different estuarine communities. Spatial and temporal dynamics of macrobenthic communities in an intertidal mudflat of the Tagus estuary were assessed in order to determine the role of this habitat in the whole estuarine functioning. Benthic macroinvertebrate communities were sampled monthly in two intertidal areas (upper and lower and in the adjoining subtidal area for one year. Macroinvertebrate density and biomass in the intertidal mudflat were higher than in the subtidal area, but no clear trends were found between the lower and upper intertidal area. Spatial patterns in the community were more pronounced than seasonal patterns. This benthic community was characterised by high densities of Pygospio elegans, Scrobicularia plana, Cyathura carinata, Hydrobia ulvae and Nereis diversicolor. Abundance and biomass values in this intertidal mudflat were considered low in comparison with other estuarine habitats, namely seagrass beds. Nevertheless, this habitat plays an important role for the main species present in the community, acting as a key area for recruitment, with high concentrations for many invertebrate species.

  18. Restoring rocky intertidal communities: Lessons from a benthic macroalgal ecosystem engineer.

    Science.gov (United States)

    Bellgrove, Alecia; McKenzie, Prudence F; Cameron, Hayley; Pocklington, Jacqueline B

    2017-04-15

    As coastal population growth increases globally, effective waste management practices are required to protect biodiversity. Water authorities are under increasing pressure to reduce the impact of sewage effluent discharged into the coastal environment and restore disturbed ecosystems. We review the role of benthic macroalgae as ecosystem engineers and focus particularly on the temperate Australasian fucoid Hormosira banksii as a case study for rocky intertidal restoration efforts. Research focussing on the roles of ecosystem engineers is lagging behind restoration research of ecosystem engineers. As such, management decisions are being made without a sound understanding of the ecology of ecosystem engineers. For successful restoration of rocky intertidal shores it is important that we assess the thresholds of engineering traits (discussed herein) and the environmental conditions under which they are important. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Interpreting Medieval Inter-tidal Features at Weelie's Taing on Papa Westray, Orkney, NE Scotland

    Science.gov (United States)

    Pollard, Edward; Gibson, Julie; Littlewood, Mark

    2016-12-01

    Investigation of the inter-tidal heritage of the Orkney Islands is used to interpret a previously perplexing complex at Weelie's Taing on Papa Westray. The study revealed a previously unknown type of harbour since identified in several locations around Orkney. Situated in exposed environmental situations, shelter is formed by an `ayre', a type of spit that encloses a loch, and which has been used historically as a landing place or crossing of the inter-tidal zone. A complex landing area, pier, tower and ship-blockage suggest Weelie's Taing was used as a harbour. Important fishing grounds exploited since the Neolithic are nearby, and Papa Westray was the site of water-focussed religious communities. It is suggested that Weelie's Taing was in use in the medieval period when Papa Westray was less isolated than today with the presence of ecclesiastical communities and situation on the Orkney-Shetland route.

  20. Community phylogenetic diversity of cyanobacterial mats associated with geothermal springs along a tropical intertidal gradient.

    Science.gov (United States)

    Jing, Hongmei; Lacap, Donnabella C; Lau, Chui Yim; Pointing, Stephen B

    2006-04-01

    The 16S rRNA gene-defined bacterial diversity of tropical intertidal geothermal vents subject to varying degrees of seawater inundation was investigated. Shannon-Weaver diversity estimates of clone library-derived sequences revealed that the hottest pools located above the mean high-water mark that did not experience seawater inundation were most diverse, followed by those that were permanently submerged below the mean low-water mark. Pools located in the intertidal were the least biodiverse, and this is attributed to the fluctuating conditions caused by periodic seawater inundation rather than physicochemical conditions per se. Phylogenetic analysis revealed that a ubiquitous Oscillatoria-like phylotype accounted for 83% of clones. Synechococcus-like phylotypes were also encountered at each location, whilst others belonging to the Chroococcales, Oscillatoriales, and other non-phototrophic bacteria occurred only at specific locations along the gradient. All cyanobacterial phylotypes displayed highest phylogenetic affinity to terrestrial thermophilic counterparts rather than marine taxa.

  1. Role of Diatoms in the Spatial-Temporal Distribution of Intracellular Nitrate in Intertidal Sediment

    DEFF Research Database (Denmark)

    Stief, P.; Kamp, A.; de Beer, D.

    2013-01-01

    Intracellular nitrate storage allows microorganisms to survive fluctuating nutrient availability and anoxic conditions in aquatic ecosystems. Here we show that diatoms, ubiquitous and highly abundant microalgae, represent major cellular reservoirs of nitrate in an intertidal flat of the German Wa...... in anaerobic nitrate respiration. Due to the widespread dominance of diatoms in microphytobenthos, the total nitrate pool in coastal marine sediments may generally be at least two times larger than derived from porewater measurements and partially be recycled to ammonium....

  2. Larval Behaviours and Their Contribution to the Distribution of the Intertidal Coral Reef Sponge Carteriospongia foliascens

    Science.gov (United States)

    Abdul Wahab, Muhammad Azmi; de Nys, Rocky; Webster, Nicole; Whalan, Steve

    2014-01-01

    Sponges (Phylum Porifera) are an evolutionary and ecologically significant group; however information on processes influencing sponge population distributions is surprisingly limited. Carteriospongia foliascens is a common Indo-Pacific sponge, which has been reported from the intertidal to the mesophotic. Interestingly, the distribution of C. foliascens at inshore reefs of the Great Barrier Reef is restricted to the intertidal with no individuals evident in adjacent subtidal habitats. The abundance of C. foliascens and substrate availability was first quantified to investigate the influence of substrate limitation on adult distribution. Pre-settlement processes of larval spawning, swimming speeds, phototaxis, vertical migration, and settlement to intertidal and subtidal substrate cues were also quantified. Notably, suitable settlement substrate (coral rubble) was not limiting in subtidal habitats. C. foliascens released up to 765 brooded larvae sponge−1 day−1 during the day, with larvae (80%±5.77) being negatively phototactic and migrating to the bottom within 40 minutes from release. Subsequently, larvae (up to 58.67%±2.91) migrated to the surface after the loss of the daylight cue (nightfall), and after 34 h post-release >98.67% (±0.67) of larvae had adopted a benthic habit regardless of light conditions. Intertidal and subtidal biofilms initiated similar settlement responses, inducing faster (as early 6 h post-release) and more successful metamorphosis (>60%) than unconditioned surfaces. C. foliascens has a high larval supply and larval behaviours that support recruitment to the subtidal. The absence of C. foliascens in subtidal habitats at inshore reefs is therefore proposed to be a potential consequence of post-settlement mortalities. PMID:24853091

  3. Persistence of Gulf War oil versus intertidal morphology and sediments - one year later

    International Nuclear Information System (INIS)

    Montello, T.M.; Hayes, M.O.; Michel, J.; Al-Momen, A.H.; Al-Mansi, A.M.; Aurand, D.V.

    1993-01-01

    A study of the persistence of oil in the intertidal habitats of the Saudi Arabian coast was carried out one year after the Gulf war spill in conjunction with the National Oceanic and Atmospheric Administration ship Mt. Mitchell's ROPME Sea Cruise. A total of 10 kilometers of transects were surveyed at 20 stations, representing heavily oiled sheltered beaches, tidal flats, algal mats, halophyte saltmarshes, and mangroves at the heads of bays

  4. Return rates from intertidal foraging from Blombos Cave to Pinnacle Point: Understanding early human economies.

    Science.gov (United States)

    De Vynck, Jan C; Anderson, Robert; Atwater, Chloe; Cowling, Richard M; Fisher, Erich C; Marean, Curtis W; Walker, Robert S; Hill, Kim

    2016-03-01

    The south coast of South Africa provides the earliest evidence for Middle Stone Age (MSA) coastal resource exploitation by early Homo sapiens. In coastal archaeology worldwide, there has been a debate over the general productivity of intertidal foraging, leading to studies that directly measure productivity in some regions, but there have been no such studies in South Africa. Here we present energetic return rate estimates for intertidal foraging along the southern coast of South Africa from Blombos Cave to Pinnacle Point. Foraging experiments were conducted with Khoi-San descendants of the region, and hourly caloric return rates for experienced foragers were measured on 41 days near low tide and through three seasons over two study years. On-site return rates varied as a function of sex, tidal level, marine habitat type and weather conditions. The overall energetic return rate from the entire sample (1492 kcal h(-1)) equals or exceeds intertidal returns reported from other hunter-gatherer studies, as well as measured return rates for activities as diverse as hunting mammals and plant collecting. Returns are projected to be exceptionally high (∼ 3400 kcal h(-1) for men, ∼ 1900 kcal h(-1) for women) under the best combination of conditions. However, because of the monthly tidal cycle, high return foraging is only possible for about 10 days per month and for only 2-3 h on those days. These experiments suggest that while intertidal resources are attractive, women and children could not have subsisted independently, nor met all their protein-lipid needs from marine resources alone, and would have required substantial additional energy and nutrients from plant gathering and/or from males contributing game. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Intertidal beach sands as monitors for heavy metal pollution in coastal water bodies

    International Nuclear Information System (INIS)

    Lacerda, L.D. de; Pfeiffer, W.C.; Fiszman, M.

    Intertidal beach sands were investigated for their use as indicators of metal transport in a contaminated water body, Sepetiba Bay, Rio de Janeiro, Brazil, and are proposed as an alternative and rapid screening method to determine metal pollution status of coastal areas. The results showed that, at least for Cu, Cr, Zn and Pb, beach sands can be included in the existing environmental monitoring programs for heavy metal pollution in water bodies. (Author) [pt

  6. Assessing sewage impact in a South-West Atlantic rocky shore intertidal algal community.

    Science.gov (United States)

    Becherucci, Maria Eugenia; Santiago, Lucerito; Benavides, Hugo Rodolfo; Vallarino, Eduardo Alberto

    2016-05-15

    The spatial and seasonal variation of the specific composition and community parameters (abundance, diversity, richness and evenness) of the intertidal algal assemblages was studied at four coastal sampling sites, distributed along an environmental gradient from the sewage water outfall of Mar del Plata, Buenos Aires, Argentina. Two of them were located close to the sewage outfall (sewage outfall impact. Ulva spp. did not reflect the typical pattern observed for other sewage pollution areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Designing an optimally proportional inorganic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jai, E-mail: jai.singh@cdu.edu.au [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia); Koblov, Alexander [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia)

    2012-09-01

    The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

  8. Designing an optimally proportional inorganic scintillator

    International Nuclear Information System (INIS)

    Singh, Jai; Koblov, Alexander

    2012-01-01

    The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

  9. Rate dependent image distortions in proportional counters

    International Nuclear Information System (INIS)

    Trow, M.W.; Bento, A.C.; Smith, A.

    1994-01-01

    The positional linearity of imaging proportional counters is affected by the intensity distribution of the incident radiation. A mechanism for this effect is described, in which drifting positive ions in the gas produce a distorting electric field which perturbs the trajectories of the primary electrons. In certain cases, the phenomenon causes an apparent improvement of the position resolution. We demonstrate the effect in a detector filled with a xenon-argon-CO 2 mixture. The images obtained are compared with the results of a simulation. If quantitative predictions for a particular detector are required, accurate values of the absolute detector gain, ion mobility and electron drift velocity are needed. ((orig.))

  10. Hydrogen high pressure proportional drift detector

    International Nuclear Information System (INIS)

    Arefiev, A.; Balaev, A.

    1983-01-01

    The design and operation performances of a proportional drift detector PDD are described. High sensitivity of the applied PAD makes it possible to detect the neutron-proton elastic scattering in the energy range of recoil protons as low as 1 keV. The PDD is filled with hydrogen up to the pressure at 40 bars. High purity of the gas is maintained by a continuously operating purification system. The detector has been operating for several years in a neutron beam at the North Area of the CERN SPS

  11. Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters.

    Directory of Open Access Journals (Sweden)

    Autumn Oczkowski

    Full Text Available Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. A recent survey and synthesis of data from four locations in Southern Rhode Island has led us to hypothesize that this warming may be amplified in the shallow (<1 m, nearshore portions of these estuaries. While intertidal areas are not typically selected as locations for long-term monitoring, we compiled data from published literature, theses, and reports that suggest that enhanced warming may be occurring, perhaps at rates three times higher than deeper estuarine waters. Warmer spring waters may be one of the factors influencing biota residing in intertidal regions both in general as well as at our specific sites. We observed greater abundance of fish, and size of Menidia sp., in recent (2010-2012 seine surveys compared to similar collections in 1962. While any linkages are speculative and data are preliminary, taken together they suggest that shallow intertidal portions of estuaries may be important places to look for the effects of climate change.

  12. Microplastic-associated bacterial assemblages in the intertidal zone of the Yangtze Estuary.

    Science.gov (United States)

    Jiang, Peilin; Zhao, Shiye; Zhu, Lixin; Li, Daoji

    2018-05-15

    Plastic trash is common in oceans. Terrestrial and marine ecosystem interactions occur in the intertidal zone where accumulation of plastic frequently occurs. However, knowledge of the plastic-associated microbial community (the plastisphere) in the intertidal zone is scanty. We used high-throughput sequencing to profile the bacterial communities attached to microplastic samples from intertidal locations around the Yangtze estuary in China. The structure and composition of plastisphere communities varied significantly among the locations. We found the taxonomic composition on microplastic samples was related to their sedimentary and aquatic origins. Correlation network analysis was used to identify keystone bacterial genera (e.g. Rhodobacterales, Sphingomonadales and Rhizobiales), which represented important microbial associations within the plastisphere community. Other species (i.e. potential pathogens) were considered as hitchhikers in the plastic attached microbial communities. Metabolic pathway analysis suggested adaptations of these bacterial assemblages to the plastic surface-colonization lifestyle. These adaptations included reduced "cell motility" and greater "xenobiotics biodegradation and metabolism." The findings illustrate the diverse microbial assemblages that occur on microplastic and increase our understanding of plastisphere ecology. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Recolonization of the intertidal and shallow subtidal community following the 2008 eruption of Alaska's Kasatochi Volcano

    Science.gov (United States)

    Jewett, S. C.; Drew, G. S.

    2014-03-01

    The intertidal and nearshore benthic communities of Kasatochi Island are described following a catastrophic volcanic eruption in 2008. Prior to the eruption, the island was surrounded by a dense bed of canopy-forming dragon kelp Eualaria fistulosa which supported a productive nearshore community. The eruption extended the coastline of the island approximately 400 m offshore to roughly the 20 m isobath. One year following the eruption a reconnaissance survey found the intertidal zone devoid of life. Subtidally, the canopy kelp, as well as limited understory algal species and associated benthic fauna on the hard substratum, were buried by debris from the eruption. The resulting substrate was comprised almost entirely of medium and coarse sands with a depauperate benthic community. Comparisons of habitat and biological communities with other nearby Aleutian Islands and the Icelandic submarine volcanic eruption of Surtsey confirm dramatic reductions in flora and fauna consistent with the initial stages of recovery from a large-scale disturbance event. Four and five years following the eruption brief visits revealed dramatic intertidal and subtidal recolonization of the flora and fauna in some areas. Signs of nesting and fledging of young pigeon guillemots Cepphus columba suggest that the recovery of the nearshore biota may have begun affecting higher trophic levels. Recolonization or lack thereof was tied to bathymetric changes from coastal and nearshore erosion over the study period.

  14. Measurements of α-emitting plutonium and americium in the intertidal sands of west Cumbria, UK

    International Nuclear Information System (INIS)

    Eakins, J.D.; Morgan, A.; Baston, G.M.N.; Pratley, F.W.; Strange, L.P.; Burton, P.J.

    1990-01-01

    Samples of surface sand and sand cores were collected from intertidal regions of west Cumbria between Silloth and Walney Island (including the Duddon Estuary) between 1982 and 1984 and analysed for 238 Pu, 239+240 Pu and 241 Am. Generally, more than 95% of the α-emitting transuranic nuclides were associated with the sand and less than 5% with entrained silt. The greatest concentrations of both plutonium and americium were found at Braystones. Concentrations declined with distance from the Sellafield Works. The largest actinide deposits occurred at Drigg (320 and 720 kBq m -2 of 239+240 Pu and 241 Am respectively). The integrated deposits in intertidal sand between Silloth and Walney Island were about 4.2 and 7.0 TBq respectively, which represent about 1% of the total α-emitting activity discharged to sea from Sellafield Works up to 1982. The corresponding value for the Duddon Estuary is about 0.3%. Only on beaches close to Sellafield did levels of man-made α-emitters exceed those of natural α-emitting nuclides. The radiological consequences of the intertidal inventory of plutonium and americium are shown to be very small and much less than from the seafood pathway. (author)

  15. Measurements of. alpha. -emitting plutonium and americium in the intertidal sands of west Cumbria, UK

    Energy Technology Data Exchange (ETDEWEB)

    Eakins, J.D.; Morgan, A.; Baston, G.M.N.; Pratley, F.W.; Strange, L.P.; Burton, P.J. (UKAEA Harwell Lab. (UK). Environmental and Medical Science Div.)

    1990-01-01

    Samples of surface sand and sand cores were collected from intertidal regions of west Cumbria between Silloth and Walney Island (including the Duddon Estuary) between 1982 and 1984 and analysed for {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am. Generally, more than 95% of the {alpha}-emitting transuranic nuclides were associated with the sand and less than 5% with entrained silt. The greatest concentrations of both plutonium and americium were found at Braystones. Concentrations declined with distance from the Sellafield Works. The largest actinide deposits occurred at Drigg (320 and 720 kBq m{sup -2} of {sup 239+240}Pu and {sup 241}Am respectively). The integrated deposits in intertidal sand between Silloth and Walney Island were about 4.2 and 7.0 TBq respectively, which represent about 1% of the total {alpha}-emitting activity discharged to sea from Sellafield Works up to 1982. The corresponding value for the Duddon Estuary is about 0.3%. Only on beaches close to Sellafield did levels of man-made {alpha}-emitters exceed those of natural {alpha}-emitting nuclides. The radiological consequences of the intertidal inventory of plutonium and americium are shown to be very small and much less than from the seafood pathway. (author).

  16. Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters.

    Science.gov (United States)

    Oczkowski, Autumn; McKinney, Richard; Ayvazian, Suzanne; Hanson, Alana; Wigand, Cathleen; Markham, Erin

    2015-01-01

    Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. A recent survey and synthesis of data from four locations in Southern Rhode Island has led us to hypothesize that this warming may be amplified in the shallow (<1 m), nearshore portions of these estuaries. While intertidal areas are not typically selected as locations for long-term monitoring, we compiled data from published literature, theses, and reports that suggest that enhanced warming may be occurring, perhaps at rates three times higher than deeper estuarine waters. Warmer spring waters may be one of the factors influencing biota residing in intertidal regions both in general as well as at our specific sites. We observed greater abundance of fish, and size of Menidia sp., in recent (2010-2012) seine surveys compared to similar collections in 1962. While any linkages are speculative and data are preliminary, taken together they suggest that shallow intertidal portions of estuaries may be important places to look for the effects of climate change.

  17. Hard science is essential to restoring soft-sediment intertidal habitats in burgeoning East Asia.

    Science.gov (United States)

    Lee, Shing Yip; Khim, Jong Seong

    2017-02-01

    Intertidal soft-sediment ecosystems such as mangrove, saltmarsh, and tidal flats face multiple stresses along the burgeoning East Asia coastline. In addition to direct habitat loss, ecosystem structure, function, and capacity for ecosystem services of these habitats are significantly affected by anthropogenic loss of hydrologic connectivity, introduction of invasive exotic species, and chemical pollution. These dramatic changes to ecosystem structure and function are illustrated by four case studies along the East Asian coast: the Mai Po Marshes in Hong Kong, the Yunxiao wetlands in Fujian, China, and the Lake Sihwa and Saemangeum tidal flats in Korea. While investment in restoration is increasing significantly in the region, the lack of key basic knowledge on aspects of the behaviour of intertidal soft-sediment ecosystems, particularly those in Asia, impairs the effectiveness of these efforts. The relationship between biodiversity and ecosystem function for relatively species-poor mangrove, seagrass, and saltmarsh systems has implications for restoration targeting monospecific plantations. The trajectory of recovery and return of ecosystem function and services is also poorly known, and may deviate from simple expectations. As many introduced species have become established along the East Asian coast, their long-term impact on ecosystem function as well as the socio-economics of coastal communities demand a multidisciplinary approach to assessing options for restoration and management. These knowledge gaps require urgent attention in order to inform future restoration and management of intertidal soft-sediment ecosystems in fast-developing East Asia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Viking-Age Sails: Form and Proportion

    Science.gov (United States)

    Bischoff, Vibeke

    2017-04-01

    Archaeological ship-finds have shed much light on the design and construction of vessels from the Viking Age. However, the exact proportions of their sails remain unknown due to the lack of fully preserved sails, or other definite indicators of their proportions. Key Viking-Age ship-finds from Scandinavia—the Oseberg Ship, the Gokstad Ship and Skuldelev 3—have all revealed traces of rigging. In all three finds, the keelson—with the mast position—is preserved, together with fastenings for the sheets and the tack, indicating the breadth of the sail. The sail area can then be estimated based on practical experience of how large a sail the specific ship can carry, in conjunction with hull form and displacement. This article presents reconstructions of the form and dimensions of rigging and sail based on the archaeological finds, evidence from iconographic and written sources, and ethnographic parallels with traditional Nordic boats. When these sources are analysed, not only do the similarities become apparent, but so too does the relative disparity between the archaeological record and the other sources. Preferential selection in terms of which source is given the greatest merit is therefore required, as it is not possible to afford them all equal value.

  19. Amplifier Design for Proportional Ionization Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Baker, W. H.

    1950-08-24

    This paper presents the requirements of a nuclear amplifier of short resolving time, designed to accept pulses of widely varying amplitudes. Data are given which show that a proportional ionization chamber loaded with a 1,000-ohm resistor develops pulses of 0.5 microsecond duration and several volts amplitude. Results indicate that seven basic requirements are imposed on the amplifier when counting soft beta and gamma radiation in the presence of alpha particles, without absorbers. It should, (1) have a fast recovery time, (2) have a relatively good low frequency response, (3) accept pulses of widely varying heights without developing spurious pulsed, (4) have a limiting output stage, (5) preserve the inherently short rise time of the chamber, (6) minimize pulse integration, and (7) have sufficient gain to detect the weak pulses well below the chamber voltage at which continuous discharge takes place. The results obtained with an amplifier which meets these requirements is described. A formula is derived which indicates that redesign of the proportional ionization chamber might eliminate the need for an amplifier. This may be possible if the radioactive particles are collimated parallel to the collecting electrode.

  20. Divine proportions in attractive and nonattractive faces.

    Science.gov (United States)

    Pancherz, Hans; Knapp, Verena; Erbe, Christina; Heiss, Anja Melina

    2010-01-01

    To test Ricketts' 1982 hypothesis that facial beauty is measurable by comparing attractive and nonattractive faces of females and males with respect to the presence of the divine proportions. The analysis of frontal view facial photos of 90 cover models (50 females, 40 males) from famous fashion magazines and of 34 attractive (29 females, five males) and 34 nonattractive (13 females, 21 males) persons selected from a group of former orthodontic patients was carried out in this study. Based on Ricketts' method, five transverse and seven vertical facial reference distances were measured and compared with the corresponding calculated divine distances expressed in phi-relationships (f=1.618). Furthermore, transverse and vertical facial disproportion indices were created. For both the models and patients, all the reference distances varied largely from respective divine values. The average deviations ranged from 0.3% to 7.8% in the female groups of models and attractive patients with no difference between them. In the male groups of models and attractive patients, the average deviations ranged from 0.2% to 11.2%. When comparing attractive and nonattractive female, as well as male, patients, deviations from the divine values for all variables were larger in the nonattractive sample. Attractive individuals have facial proportions closer to the divine values than nonattractive ones. In accordance with the hypothesis of Ricketts, facial beauty is measurable to some degree. COPYRIGHT © 2009 BY QUINTESSENCE PUBLISHING CO, INC.

  1. Kalman-predictive-proportional-integral-derivative (KPPID)

    International Nuclear Information System (INIS)

    Fluerasu, A.; Sutton, M.

    2004-01-01

    With third generation synchrotron X-ray sources, it is possible to acquire detailed structural information about the system under study with time resolution orders of magnitude faster than was possible a few years ago. These advances have generated many new challenges for changing and controlling the state of the system on very short time scales, in a uniform and controlled manner. For our particular X-ray experiments on crystallization or order-disorder phase transitions in metallic alloys, we need to change the sample temperature by hundreds of degrees as fast as possible while avoiding over or under shooting. To achieve this, we designed and implemented a computer-controlled temperature tracking system which combines standard Proportional-Integral-Derivative (PID) feedback, thermal modeling and finite difference thermal calculations (feedforward), and Kalman filtering of the temperature readings in order to reduce the noise. The resulting Kalman-Predictive-Proportional-Integral-Derivative (KPPID) algorithm allows us to obtain accurate control, to minimize the response time and to avoid over/under shooting, even in systems with inherently noisy temperature readings and time delays. The KPPID temperature controller was successfully implemented at the Advanced Photon Source at Argonne National Laboratories and was used to perform coherent and time-resolved X-ray diffraction experiments.

  2. Proportional-Integral-Resonant AC Current Controller

    Directory of Open Access Journals (Sweden)

    STOJIC, D.

    2017-02-01

    Full Text Available In this paper an improved stationary-frame AC current controller based on the proportional-integral-resonant control action (PIR is proposed. Namely, the novel two-parameter PIR controller is applied in the stationary-frame AC current control, accompanied by the corresponding parameter-tuning procedure. In this way, the proportional-resonant (PR controller, common in the stationary-frame AC current control, is extended by the integral (I action in order to enable the AC current DC component tracking, and, also, to enable the DC disturbance compensation, caused by the voltage source inverter (VSI nonidealities and by nonlinear loads. The proposed controller parameter-tuning procedure is based on the three-phase back-EMF-type load, which corresponds to a wide range of AC power converter applications, such as AC motor drives, uninterruptible power supplies, and active filters. While the PIR controllers commonly have three parameters, the novel controller has two. Also, the provided parameter-tuning procedure needs only one parameter to be tuned in relation to the load and power converter model parameters, since the second controller parameter is directly derived from the required controller bandwidth value. The dynamic performance of the proposed controller is verified by means of simulation and experimental runs.

  3. Patterns of recruitment of the sand smelt (Atherina presbyter on rocky intertidal habitats

    Directory of Open Access Journals (Sweden)

    Frederico Almada

    2015-11-01

    Full Text Available The Portuguese coast is located in a biogeographical transition zone between temperate and subtropical waters making it especially vulnerable to the effects of climate change. Several fish species struggle to cope with these annual changing conditions, particularly species that strongly depend on intertidal habitats which are expected to endure higher ecological fluctuations. Sand smelt young recruits and larvae were collected at the west coast of Portugal in the intertidal by hand-netting, and in the subtidal with light traps and scuba diving with plankton nets attached to scooters (Parede/Avencas: 38º 41’ N, 9º 21’W and Arrábida: 38º 28’ N, 8º 59’W, respectively. Due to the morphological similarities with other congeneric species young specimens were regularly collected and identified through genetic analysis. All samples were assigned to the same species: A. presbyter. Results showed that A. presbyter is one of the most abundant non-resident fish species in these rocky coastal areas, representing 49% (n=93.958 of the total number of individuals sighted in the intertidal from 2009-2015, but only 0.55% of the total number of individuals sampled in the subtidal (n=176 with both methods from 2011-2013. Distribution patterns showed that recruits (TL 0.8-6.8 cm concentrated within the intertidal area between March and December. Younger cohorts (TL 0.8-1.2 cm are captured almost exclusively in these areas including confined intertidal channels and large pools between March and August, suggesting that reproduction and spawning can occur for a period of 6 months. Inter-annual seasonal variations from 2009 to 2015 showed irregular water temperature profiles, especially in 2011 and 2012, which may dramatically affect the reproductive success of this species, not only reducing the number of recruits but also shortening the recruitment period from 10 to 5 months. Globally, 46% of the coastlines have experienced a significant decrease in the

  4. A novel bioassay using the barnacle Amphibalanus amphitrite to evaluate chronic effects of aluminium, gallium and molybdenum in tropical marine receiving environments.

    Science.gov (United States)

    van Dam, Joost W; Trenfield, Melanie A; Harries, Simon J; Streten, Claire; Harford, Andrew J; Parry, David; van Dam, Rick A

    2016-11-15

    A need exists for appropriate tools to evaluate risk and monitor potential effects of contaminants in tropical marine environments, as currently impact assessments are conducted by non-representative approaches. Here, a novel bioassay is presented that allows for the estimation of the chronic toxicity of contaminants in receiving tropical marine environments. The bioassay is conducted using planktonic larvae of the barnacle Amphibalanus amphitrite and is targeted at generating environmentally relevant, chronic toxicity data for water quality guideline derivation or compliance testing. The developmental endpoint demonstrated a consistently high control performance, validated through the use of copper as a reference toxicant. In addition, the biological effects of aluminium, gallium and molybdenum were assessed. The endpoint expressed high sensitivity to copper and moderate sensitivity to aluminium, whereas gallium and molybdenum exhibited no discernible effects, even at high concentrations, providing valuable information on the toxicity of these elements in tropical marine waters. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  5. Reproduction and larval development in three scalpellid barnacles, Scalpellum scalpellum (Linnaeus 1767), Ornatoscalpellum stroemii (M. Sars 1859) and Arcoscalpellum michelottianum (Seguenza 1876), Crustacea: Cirripedia: Thoracica): implications for reproduction

    DEFF Research Database (Denmark)

    Buhl-Mortensen, Lene; Høeg, Jens Thorvald

    2006-01-01

    We studied reproduction and larval development in three species of pedunculated barnacles with different depth distribution, that is, Scalpellum scalpellum (30-200 m), Ornatoscalpellum stroemii (100-1,600 m) and Arcoscalpellum michelottianum (64-5,190 m). Morphology, position and number of males...... than the other two species. We hypothesize that the observed differences in reproductive system and mode of development in the three species represent adaptations to their different habitats. S. scalpellum are mainly transported by currents in the coastal sublittoral zone. O. stroemii is presumably...... in the female/hermaphrodite, type of larval development and the number and size of eggs were recorded. All three species have a pair of pocket-like receptacles, each of which can host only a single male in O. stroemii, up to five males in S. scalpellum and up to 12 males in A. michelottianum. Eggs and larvae...

  6. Galkinius Perreault, 2014 or Darwiniella (Anderson, 1992? A new coral-associated barnacle sharing characteristics of these two genera in Pacific waters (Crustacea, Cirripedia, Thoracica, Pyrgomatidae

    Directory of Open Access Journals (Sweden)

    Benny Kwok Kan Chan

    2017-12-01

    Full Text Available A new species of coral associated barnacle (Balanomorpha: Pyrgomatidae sharing morphological features of Darwiniella (Anderson, 1992 and Galkinius Perreault, 2014 is described. It has a fused shell and opercular plates, characteristic of Darwiniella. However, the morphology of the tergum and somatic body are closer to Galkinius. Sequence divergence of mitochondrial DNA 12S rDNA and COI reveals this new species clusters with the Galkinius clade. Therefore this new form is assigned to the genus Galkinius, as G. maculosus sp. n. Concomitantly the diagnosis of Galkinius is emended to include species with fused or four- plated shells and fused opercular plates. The new species is distinct from all Galkinius species in having a fused shell. It inhabits the corals Lobophyllia spp. and is distributed from the Dongsha Atoll in the South China Sea, Orchid Island of Taiwan in the Pacific Ocean, to Madang in Papua New Guinea waters.

  7. BCE selector valves and flow proportional sampler

    International Nuclear Information System (INIS)

    Rippy, G.L.

    1994-01-01

    This Acceptance Test Procedure (ATP) has been prepared to demonstrate that the Electrical/Instrumentation systems for the B-Plant Process Condensate Treatment Facility (BCE) function as required by project criteria. Tests will be run to: Verify the operation of the solenoid valve and associated limit switches installed for the BCE portion of W-007H; Operate the solenoid valve and verify the proper operation of the associated limit switches based on the position of the solenoid valve;and, Demonstrate the integrity of the Sample Failure Alarm Relay XFA-211BA-BCE-1, and Power Failure ALarm Relay JFA-211BA-BCE-1 located inside the Flow Proportional Sampler in Building 211 BA

  8. Absolute calibration of TFTR helium proportional counters

    International Nuclear Information System (INIS)

    Strachan, J.D.; Diesso, M.; Jassby, D.; Johnson, L.; McCauley, S.; Munsat, T.; Roquemore, A.L.; Loughlin, M.

    1995-06-01

    The TFTR helium proportional counters are located in the central five (5) channels of the TFTR multichannel neutron collimator. These detectors were absolutely calibrated using a 14 MeV neutron generator positioned at the horizontal midplane of the TFTR vacuum vessel. The neutron generator position was scanned in centimeter steps to determine the collimator aperture width to 14 MeV neutrons and the absolute sensitivity of each channel. Neutron profiles were measured for TFTR plasmas with time resolution between 5 msec and 50 msec depending upon count rates. The He detectors were used to measure the burnup of 1 MeV tritons in deuterium plasmas, the transport of tritium in trace tritium experiments, and the residual tritium levels in plasmas following 50:50 DT experiments

  9. CWRU multiwire proportional counter readout system

    International Nuclear Information System (INIS)

    Bevington, P.R.; Leskovec, R.A.

    1977-01-01

    An electronic system is described which translates pulses from individual wires of multiwire proportional counters into binary addresses indicating the location of the wires in the chambers. The system combines a fast (<100 ns) serial scan of an event buffer with parallel encoding to provide fast transfer of addresses (250 ns per hit). The buffer has provision for disabling the input less than 40 ns after detection of an event to suppress recording of multiple hits caused by individual events. The encoder can digitize the address of every hit encountered or just the first addresses of contiguous hits. The system includes a coincidence trigger for determining whether timing criteria have been satisfied between chambers and with external devices. Events which do not meet the coincidence criteria are typically reset within 400 ns. The addresses are transferred to a computer interface through CAMAC modules. Multiple buffering permits further data acquisition during CAMAC transfer cycles. (Auth.)

  10. Fabrication of preamplifier for proportional counter

    International Nuclear Information System (INIS)

    Lotfi, Y.; Yazdanpanah, M.; Talebi, B.; Mohammadi, A.; Etaati, Gh.

    2002-01-01

    We have tried to describe techniques of preamplifier fabrication for proportional counter. At first electronic circuit of preamplifier has been analyzed by means of Or cad 9.1. Then we assembled the circuit. Thereafter essential and standard parameters of preamplifier has been measured and compared with foreign made one, according to IEEE standard method. (IEEE Std 301-1988) Specification for our preamplifier is: 1. Rise time of output plus: 25 nsec. 2. Fall time of output pulse: 50μ sec. 3. Charge sensitive: 46.3 mV/pc. 4. Average noise: 500 ion pair (rms) 5. Count R ate L imit: 9.14*10 10 Count/sec. 6. Resolution: %1.3 7. Spectrum of Bf3 detector to 300μ Ci Am-Be source for this preamplifier is the same as foreign one. On the Whole comparison of this preamplifier with the foreign one shows that their parameters similarity is about %95

  11. Tables of Confidence Limits for Proportions

    Science.gov (United States)

    1990-09-01

    0.972 180 49 0.319 0.332 0,357 175 165 0.964 0.969 0.976 ISO 50 0.325 0.338 0.363 175 166 0.969 0.973 0.980 180 51 0.331 0.344 0.368 175 167 0.973 0.977...0.528 180 18 0.135 0 145 0.164 180 19 0.141 0.151 0.171 ISO 80 0.495 0,508 0.534 347 UPPER CONFIDENCE LIMIT FOR PROPORTIONS CONFIDENCE LEVEL...500 409 0.8401 0.8459 0.8565 500 355 0.7364 0.7434 0.7564 500 356 0.7383 0.7453 0.7582 500 410 0.8420 0.8478 0 8583 500 357 0.7402 0.7472 0.7602 500

  12. Proportional chamber with data analog output

    International Nuclear Information System (INIS)

    Popov, V.E.; Prokof'ev, A.N.

    1977-01-01

    A proportional multiwier chamber is described. The chamber makes it possible to determine angles at wich a pion strikes a polarized target. A delay line, made of 60-core flat cable is used for removing signals from the chamber. From the delay line, signals are amplified and successively injected into shapers and a time-to-amplitude converter. An amplitude of the time-to amplitude converter output signal unambiguously determines the coordinate of a point at which a particle strikes the chamber plane. There are also given circuits of amplifiers, which consist of a preamplifier with gain 30 and a main amplifier with adjustable gain. Data on testing the chamber with the 450 MeV pion beam is demonstrated. The chamber features an efficiency of about 98 per cent under load of 2x10 5 s -1

  13. Proportional representation apportionment methods and their applications

    CERN Document Server

    Pukelsheim, Friedrich

    2017-01-01

    The book offers an in-depth study of the translation of vote counts into seat numbers in proportional representation systems  – an approach guided by practical needs. It also provides plenty of empirical instances illustrating the results. It analyzes in detail the 2014 elections to the European Parliament in the 28 member states, as well as the 2009 and 2013 elections to the German Bundestag. This second edition is a complete revision and expanded version of the first edition published in 2014, and many empirical election results that serve as examples have been updated. Further, a final chapter has been added assembling biographical sketches and authoritative quotes from individuals who pioneered the development of apportionment methodology. The mathematical exposition and the interrelations with political science and constitutional jurisprudence make this an apt resource for interdisciplinary courses and seminars on electoral systems and apportionment methods.

  14. Quality measurement by proportional counter with B

    International Nuclear Information System (INIS)

    Onizuka, Yoshihiko; Endo, Satoru; Tanaka, Kenichi

    2005-01-01

    The dosimetry of air and the tissue-equivalent phantom made of acryl are carried out by the tissue-equivalent proportional counter (TEPC) and TEPC with wall contained B, and both results were compared. The changes of quality with distance from the beam center are determined by the frequency mean renewal energy y F (y)and the dose mean renewal energy y D (y) as indicators of quality. Both y F (y)and y D (y) of tissue-equivalent phantom are larger than air, but very large change was not observed in all distance. The dose rate is determined by y D (y), the number of events and measurement time. Change of dose rate was larger than the change of quality. The maximum value of dose rate depended on γray and neutron beam showed at the point 2 cm away from the center. (S.Y.)

  15. Proportional counter system for radiation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, M; Okudera, S

    1970-11-21

    A gas such as Xe or Kr employed in counter tubes is charged into the counter tube of a gas-flow type proportional counter for radiation measurement and into a vessel having a volume larger than that of the counter tube. The vessel communicates with the counter tube to circulate the gas via a pump through both the vessel and tube during measurement. An organic film such as a polyester synthetic resin film is used for the window of the counter tube to measure X-rays in the long wavelength range. Accordingly, a wide range of X-rays can be measured including both long and short wavelengths ranges by utilizing only one counter tube, thus permitting the gases employed to be effectively used.

  16. Count rate effect in proportional counters

    International Nuclear Information System (INIS)

    Bednarek, B.

    1980-01-01

    A new concept is presented explaining changes in spectrometric parameters of proportional counters which occur due to varying count rate. The basic feature of this concept is that the gas gain of the counter remains constant in a wide range of count rate and that the decrease in the pulse amplitude and the detorioration of the energy resolution observed are the results of changes in the shape of original current pulses generated in the active volume of the counter. In order to confirm the validity of this statement, measurements of the gas amplification factor have been made in a wide count rate range. It is shown that above a certain critical value the gas gain depends on both the operating voltage and the count rate. (author)

  17. Management of the stalked barnacle (Pollicipes pollicipes fishery in the Berlengas Nature Reserve (Portugal: evaluation of bag and size limit regulation measures

    Directory of Open Access Journals (Sweden)

    David Jacinto

    2011-04-01

    Full Text Available The stalked barnacle Pollicipes pollicipes (Gmelin, 1790 is an important shellfish resource in Portugal. Due to the social-economic importance of barnacle harvesting, a management plan aimed at achieving a controlled and sustainable activity (including temporal and spatial closures, rotational harvesting, a limited number of harvesting licenses, bag and size limits for catches and catch reporting was implemented in 2000 at the Berlengas Nature Reserve (RNB in central Portugal. We evaluated the bag and size limits imposed by the management plan, performing observations on harvesting activity and asking licensed harvesters and RNB staff about these measures. Both inquiries and observations suggest that licensed harvesters are not following the bag and size limits imposed. Mean amounts captured in RNB varied from 14 to 24 kg per harvester/day, but 25% of the observations corresponded to higher catches per individual than the total amount allowed (20 kg. Only half of the sampled amounts (taken in autumn 2005 and 2006 were in agreement with the size limit regulation and 50% of the total biomass comprised individuals of maximal rostro-carinal length (RC ≥ 25 mm. For most harvesters, size limit is the most difficult management rule to fulfil. Both harvesters and RNB staff agree that surveillance is scarce and is a major problem of this fishing activity. In order to achieve a more sustainable use of this resource, we propose the implementation of a more effective surveillance and monitoring plan, the definition of a unique landing site, the maintenance of the bag limit (20 kg and a reduction of the size limit (50% of total biomass comprising individuals ≥ 22 mm RC.

  18. Construction of an adult barnacle (Balanus amphitrite cDNA library and selection of reference genes for quantitative RT-PCR studies

    Directory of Open Access Journals (Sweden)

    Burgess J Grant

    2009-06-01

    Full Text Available Abstract Background Balanus amphitrite is a barnacle commonly used in biofouling research. Although many aspects of its biology have been elucidated, the lack of genetic information is impeding a molecular understanding of its life cycle. As part of a wider multidisciplinary approach to reveal the biogenic cues influencing barnacle settlement and metamorphosis, we have sequenced and annotated the first cDNA library for B. amphitrite. We also present a systematic validation of potential reference genes for normalization of quantitative real-time PCR (qRT-PCR data obtained from different developmental stages of this animal. Results We generated a cDNA library containing expressed sequence tags (ESTs from adult B. amphitrite. A total of 609 unique sequences (comprising 79 assembled clusters and 530 singlets were derived from 905 reliable unidirectionally sequenced ESTs. Bioinformatics tools such as BLAST, HMMer and InterPro were employed to allow functional annotation of the ESTs. Based on these analyses, we selected 11 genes to study their ability to normalize qRT-PCR data. Total RNA extracted from 7 developmental stages was reverse transcribed and the expression stability of the selected genes was compared using geNorm, BestKeeper and NormFinder. These software programs produced highly comparable results, with the most stable gene being mt-cyb, while tuba, tubb and cp1 were clearly unsuitable for data normalization. Conclusion The collection of B. amphitrite ESTs and their annotation has been made publically available representing an important resource for both basic and applied research on this species. We developed a qRT-PCR assay to determine the most reliable reference genes. Transcripts encoding cytochrome b and NADH dehydrogenase subunit 1 were expressed most stably, although other genes also performed well and could prove useful to normalize gene expression studies.

  19. A phenomenological SMA model for combined axial–torsional proportional/non-proportional loading conditions

    International Nuclear Information System (INIS)

    Bodaghi, M.; Damanpack, A.R.; Aghdam, M.M.; Shakeri, M.

    2013-01-01

    In this paper, a simple and robust phenomenological model for shape memory alloys (SMAs) is proposed to simulate main features of SMAs under uniaxial as well as biaxial combined axial–torsional proportional/non-proportional loadings. The constitutive model for polycrystalline SMAs is developed within the framework of continuum thermodynamics of irreversible processes. The model nominates the volume fractions of self-accommodated and oriented martensite as scalar internal variables and the preferred direction of oriented martensitic variants as directional internal variable. An algorithm is introduced to develop explicit relationships for the thermo-mechanical behavior of SMAs under uniaxial and biaxial combined axial–torsional proportional/non-proportional loading conditions and also thermal loading. It is shown that the model is able to simulate main aspects of SMAs including self-accommodation, martensitic transformation, orientation and reorientation of martensite, shape memory effect, ferro-elasticity and pseudo-elasticity. A description of the time-discrete counterpart of the proposed SMA model is presented. Experimental results of uniaxial tension and biaxial combined tension–torsion non-proportional tests are simulated and a good qualitative correlation between numerical and experimental responses is achieved. Due to simplicity and accuracy, the model is expected to be used in the future studies dealing with the analysis of SMA devices in which two stress components including one normal and one shear stress are dominant

  20. Kite aerial photography for low-cost, ultra-high spatial resolution multi-spectral mapping of intertidal landscapes.

    Directory of Open Access Journals (Sweden)

    Mitch Bryson

    Full Text Available Intertidal ecosystems have primarily been studied using field-based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time that could complement field-based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging provide data at limited spatial and temporal resolutions and relatively high costs for small-scale environmental science and ecologically-focussed studies. In this paper, we describe a low-cost, kite-based imaging system and photogrammetric/mapping procedure that was developed for constructing high-resolution, three-dimensional, multi-spectral terrain models of intertidal rocky shores. The processing procedure uses automatic image feature detection and matching, structure-from-motion and photo-textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer-grade digital cameras. The resulting maps combine imagery at visible and near-infrared wavelengths and topographic information at sub-centimeter resolutions over an intertidal shoreline 200 m long, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rocky shore at Jervis Bay, New South Wales, Australia. Potential uses of this technique include mapping of plant (micro- and macro-algae and animal (e.g. gastropods assemblages at multiple spatial and temporal scales.

  1. Kite aerial photography for low-cost, ultra-high spatial resolution multi-spectral mapping of intertidal landscapes.

    Science.gov (United States)

    Bryson, Mitch; Johnson-Roberson, Matthew; Murphy, Richard J; Bongiorno, Daniel

    2013-01-01

    Intertidal ecosystems have primarily been studied using field-based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time that could complement field-based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging) provide data at limited spatial and temporal resolutions and relatively high costs for small-scale environmental science and ecologically-focussed studies. In this paper, we describe a low-cost, kite-based imaging system and photogrammetric/mapping procedure that was developed for constructing high-resolution, three-dimensional, multi-spectral terrain models of intertidal rocky shores. The processing procedure uses automatic image feature detection and matching, structure-from-motion and photo-textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer-grade digital cameras. The resulting maps combine imagery at visible and near-infrared wavelengths and topographic information at sub-centimeter resolutions over an intertidal shoreline 200 m long, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rocky shore at Jervis Bay, New South Wales, Australia. Potential uses of this technique include mapping of plant (micro- and macro-algae) and animal (e.g. gastropods) assemblages at multiple spatial and temporal scales.

  2. Calibration of proportional counters in microdosimetry

    International Nuclear Information System (INIS)

    Varma, M.N.

    1982-01-01

    Many microdosimetric spectra for low LET as well as high LET radiations are measured using commercially available (similar to EG and G) Rossi proportional counters. This paper discusses the corrections to be applied to data when calibration of the counter is made using one type of radiation, and then the counter is used in a different radiation field. The principal correction factor is due to differences in W-value of the radiation used for calibration and the radiation for which microdosimetric measurements are made. Both propane and methane base tissue-equivalent (TE) gases are used in these counters. When calibrating the detectors, it is important to use the correct stopping power value for that gas. Deviations in y-bar/sub F/ and y-bar/sub D/ are calculated for 60 Co using different extrapolation procedures from 0.15 keV/μm to zero event size. These deviations can be as large as 30%. Advantages of reporting microdosimetric parameters such as y-bar/sub F/ and y-bar/sub D/ above a certain minimum cut-off are discussed

  3. Environmental drivers of sapwood and heartwood proportions

    Science.gov (United States)

    Thurner, Martin; Beer, Christian

    2017-04-01

    Recent advances combining information on stem volume from remote sensing with allometric relationships derived from forest inventory databases have led to spatially continuous estimates of stem, branch, root and foliage biomass in northern boreal and temperate forests. However, a separation of stem biomass into sapwood and heartwood mass has remained unsolved, despite their important differences in biogeochemical function, for instance concerning their contribution to tree respiratory costs. Although relationships between sapwood cross-sectional area and supported leaf area are well established, less is known about relations between sapwood or heartwood mass and other traits (e.g. stem mass), since these biomass compartments are more difficult to measure in practice. Here we investigate the variability in sapwood and heartwood proportions and determining environmental factors. For this task we explore an available biomass and allometry database (BAAD) and study relative sapwood and heartwood area, volume, mass and density in dependence of tree species, age and climate. First, a theoretical framework on how to estimate sap- and heartwood mass from stem mass is developed. Subsequently, the underlying assumptions and relationships are explored with the help of the BAAD. The established relationships can be used to derive spatially continuous sapwood and heartwood mass estimates by applying them to remote sensing based stem volume products. This would be a fundamental step forward to a data-driven estimate of autotrophic respiration.

  4. From Space to the Rocky Intertidal: Using NASA MODIS Sea Surface Temperature and NOAA Water Temperature to Predict Intertidal Logger Temperature

    Directory of Open Access Journals (Sweden)

    Jessica R. P. Sutton

    2017-02-01

    Full Text Available The development of satellite-derived datasets has greatly facilitated large-scale ecological studies, as in situ observations are spatially sparse and expensive undertakings. We tested the efficacy of using satellite sea surface temperature (SST collected by NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS and local water temperature collected from NOAA buoys and onshore stations to estimate submerged intertidal mussel logger temperatures. Daily SST and local water temperatures were compared to mussel logger temperatures at five study sites located along the Oregon coastline. We found that satellite-derived SSTs and local water temperatures were similarly correlated to the submerged mussel logger temperatures. This finding suggests that satellite-derived SSTs may be used in conjunction with local water temperatures to understand the temporal and spatial variation of mussel logger temperatures. While there are limitations to using satellite-derived temperature for ecological studies, including issues with temporal and spatial resolution, our results are promising.

  5. Molecular characterization of the α-subunit of Na⁺/K⁺ ATPase from the euryhaline barnacle Balanus improvisus reveals multiple genes and differential expression of alternative splice variants.

    Directory of Open Access Journals (Sweden)

    Ulrika Lind

    Full Text Available The euryhaline bay barnacle Balanus improvisus has one of the broadest salinity tolerances of any barnacle species. It is able to complete its life cycle in salinities close to freshwater (3 PSU up to fully marine conditions (35 PSU and is regarded as one of few truly brackish-water species. Na⁺/K⁺ ATPase (NAK has been shown to be important for osmoregulation when marine organisms are challenged by changing salinities, and we therefore cloned and examined the expression of different NAKs from B. improvisus. We found two main gene variants, NAK1 and NAK2, which were approximately 70% identical at the protein level. The NAK1 mRNA existed in a long and short variant with the encoded proteins differing only by 27 N-terminal amino acids. This N-terminal stretch was coded for by a separate exon, and the two variants of NAK1 mRNAs appeared to be created by alternative splicing. We furthermore showed that the two NAK1 isoforms were differentially expressed in different life stages and in various tissues of adult barnacle, i.e the long isoform was predominant in cyprids and in adult cirri. In barnacle cyprid larvae that were exposed to a combination of different salinities and pCO2 levels, the expression of the long NAK1 mRNA increased relative to the short in low salinities. We suggest that the alternatively spliced long variant of the Nak1 protein might be of importance for osmoregulation in B. improvisus in low salinity conditions.

  6. Study of the rocky Intertidal communities of central and northern California: Years 3 and 4. Volume 3 of 5

    International Nuclear Information System (INIS)

    Hardin, D.

    1990-08-01

    The study objectives are to describe seasonal and successional variation in rocky Intertidal community structure; determine the response of rocky Intertidal communities to natural and human-induced disturbances and correlate these responses with successional, seasonal, and latitudinal variation; and correlate life history information and oil toxicity data with data from this and other relevant studies. The Year III and IV report is for the third (1987) and fourth (1988) years of a five-year field experimental study investigating two biological assemblages, the Mytilus assemblage and the Endocladia/Mastocarpus papillatus assemblage, that are being studied at six sites along the California coast. Experimental treatments include clearing three plots in spring 1985 and three plots in fall 1985. Data from the program will be correlated with oil toxicity data and other studies to provide indications of the long term effects of an oil spill on rocky Intertidal communities. The report is volume 3 of a 5 volume set

  7. Are all intertidal wetlands naturally created equal? Bottlenecks, thresholds and knowledge gaps to mangrove and saltmarsh ecosystems

    Science.gov (United States)

    Friess, Daniel A.; Krauss, Ken W.; Horstman, Erik M.; Balke, Thorsten; Bouma, Tjeerd J.; Galli, Demis; Webb, Edward L.

    2011-01-01

    Intertidal wetlands such as saltmarshes and mangroves provide numerous important ecological functions, though they are in rapid and global decline. To better conserve and restore these wetland ecosystems, we need an understanding of the fundamental natural bottlenecks and thresholds to their establishment and long-term ecological maintenance. Despite inhabiting similar intertidal positions, the biological traits of these systems differ markedly in structure, phenology, life history, phylogeny and dispersal, suggesting large differences in biophysical interactions. By providing the first systematic comparison between saltmarshes and mangroves, we unravel how the interplay between species-specific life-history traits, biophysical interactions and biogeomorphological feedback processes determine where, when and what wetland can establish, the thresholds to long-term ecosystem stability, and constraints to genetic connectivity between intertidal wetland populations at the landscape level. To understand these process interactions, research into the constraints to wetland development, and biological adaptations to overcome these critical bottlenecks and thresholds requires a truly interdisciplinary approach.

  8. Natural disturbance shapes benthic intertidal macroinvertebrate communities of high latitude river deltas

    Science.gov (United States)

    Churchwell, Roy T.; Kendall, Steve J.; Blanchard, Amy L.; Dunton, Kenneth H.; Powell, Abby N.

    2016-01-01

    Unlike lower latitude coastlines, the estuarine nearshore zones of the Alaskan Beaufort Sea are icebound and frozen up to 9 months annually. This annual freezing event represents a dramatic physical disturbance to fauna living within intertidal sediments. The main objectives of this study were to describe the benthic communities of Beaufort Sea deltas, including temporal changes and trophic structure. Understanding benthic invertebrate communities provided a baseline for concurrent research on shorebird foraging ecology at these sites. We found that despite continuous year-to-year episodes of annual freezing, these estuarine deltas are populated by a range of invertebrates that represent both marine and freshwater assemblages. Freshwater organisms like Diptera and Oligochaeta not only survive this extreme event, but a marine invasion of infaunal organisms such as Amphipoda and Polychaeta rapidly recolonizes the delta mudflats following ice ablation. These delta sediments of sand, silt, and clay are fine in structure compared to sediments of other Beaufort Sea coastal intertidal habitats. The relatively depauperate invertebrate community that ultimately develops is composed of marine and freshwater benthic invertebrates. The composition of the infauna also reflects two strategies that make life on Beaufort Sea deltas possible: a migration of marine organisms from deeper lagoons to the intertidal and freshwater biota that survive the 9-month ice-covered period in frozen sediments. Stable isotopic analyses reveal that both infaunal assemblages assimilate marine and terrestrial sources of organic carbon. These results provide some of the first quantitative information on the infaunal food resources of shallow arctic estuarine systems and the long-term persistence of these invertebrate assemblages. Our data help explain the presence of large numbers of shorebirds in these habitats during the brief summer open-water period and their trophic importance to migrating

  9. Effects of predation by sea ducks on clam abundance in soft-bottom intertidal habitats

    Science.gov (United States)

    Lewis, Tyler; Esler, Daniel N.; Boyd, W. Sean

    2007-01-01

    Recent studies have documented strong, top-down predation effects of sea ducks on mussel populations in rocky intertidal communities. However, the impact of these gregarious predators in soft-bottom communities has been largely unexplored. We evaluated effects of predation by wintering surf scoters Melanitta perspicillata and white-winged scoters M. fusca on clam populations in soft-bottom intertidal habitats of the Strait of Georgia, British Columbia. Specifically, we documented spatial and temporal variation in clam density (clams m–2), scoter diet composition, and the consequences of scoter predation on clam abundance. Of the 3 most numerous clams, Manila clams Venerupis philippinarum and varnish clams Nuttallia obscurata were the primary prey items of both scoter species, while clams of the genus Macoma were rarely consumed by scoters. Between scoter arrival in the fall and departure in the spring, Manila clams decreased in density at most sample sites, while varnish clam densities did not change or declined slightly. Our estimates of numbers of clams consumed by scoters accounted for most of the observed declines in combined abundance of Manila and varnish clams, despite the presence of numerous other vertebrate and invertebrate species known to consume clams. For Macoma spp., we detected an over-winter increase in density, presumably due to growth of clams too small to be retained by our sieve (<5 mm) during fall sampling, in addition to the lack of predation pressure by scoters. These results illustrate the strong predation potential of scoters in soft-bottom intertidal habitats, as well as their potentially important role in shaping community structure.

  10. Distribution of oil from the Gulf War spill within intertidal habitats - one year later

    International Nuclear Information System (INIS)

    Hayes, M.O.; Michel, J.; Montelo, T.M.; Al-Mansi, A.M.; Jensen, J.R.; Narumalani, S.; Aurand, D.V.; Al-Momen, A.H.; Thayer, G.W.

    1993-01-01

    Results of a land-based intertidal survey of the impacts of the Gulf War oil spill on the Saudi Arabian coast, carried out from 1 March to 4 April 1992 in conjunction with Leg II of the NOAA ship Mt. Mitchell's ROPME Sea cruise, show that there is a striking correlation between the near shore geomorphology and the persistence of intertidal oil. Significant quantities of oil (measured in millions of gallons) remained in the sediments of the sheltered tidal flat/marsh areas, and significant erosion of oiled sediments has occurred along many of the outer exposed areas. A massive asphalt pavement, tens of meters wide and over 20 kilometers long, which is believed to have formed as a result of the Nowruz spill of 1983, occurs along the outer coast of the Abu Ali headland. Along certain other exposed outer sand beaches, conditions are conducive to the formation and preservation of a similar asphalt pavement as a result of the Gulf War spill. The most severely impacted areas studied were several halophyte marsh algal mat complexes and mudflats at the heads of sheltered bays, where all the halophytes were dead and there was no sign of living epibiota in the mid to upper intertidal areas. Before the spill, burrowing infauna, such as crabs and polychaetes, occurred in large numbers in these sheltered areas. The previously occupied burrows were heavily oiled, with some containing liquid black oil to depths of over 40 cm. The deep penetration of oil into the burrows and probable slow weathering rates of the oil could result in many years of pollution of these sheltered habitats. Depths of penetration of oil into bubble sand exceeding 40 cm were found at several localities. This deep oil will also remain in the sediment for many years, because of the slow erosion rates that occur in these sheltered environments. Many unoiled portions were rich in epifaunal and infaunal populations of invertebrates and plants. Shorebirds were observed feeding in these unoiled areas

  11. Sea otters homogenize mussel beds and reduce habitat provisioning in a rocky intertidal ecosystem.

    Directory of Open Access Journals (Sweden)

    Gerald G Singh

    Full Text Available Sea otters (Enhydra lutris are keystone predators that consume a variety of benthic invertebrates, including the intertidal mussel, Mytilus californianus. By virtue of their competitive dominance, large size, and longevity, M. californianus are ecosystem engineers that form structurally complex beds that provide habitat for diverse invertebrate communities. We investigated whether otters affect mussel bed characteristics (i.e. mussel length distributions, mussel bed depth, and biomass and associated community structure (i.e. biomass, alpha and beta diversity by comparing four regions that varied in their histories of sea otter occupancy on the west coast of British Columbia and northern Washington. Mussel bed depth and average mussel lengths were 1.5 times lower in regions occupied by otters for >20 years than those occupied for <5 yrs. Diversity of mussel bed associated communities did not differ between regions; however, the total biomass of species associated with mussel beds was more than three-times higher where sea otters were absent. We examined alternative explanations for differences in mussel bed community structure, including among-region variation in oceanographic conditions and abundance of the predatory sea star Pisaster ochraceus. We cannot discount multiple drivers shaping mussel beds, but our findings indicate the sea otters are an important one. We conclude that, similar to their effects on subtidal benthic invertebrates, sea otters reduce the size distributions of intertidal mussels and, thereby, habitat available to support associated communities. Our study indicates that by reducing populations of habitat-providing intertidal mussels, sea otters may have substantial indirect effects on associated communities.

  12. Aeolian sand transport over complex intertidal bar-trough beach topography

    Science.gov (United States)

    Anthony, Edward J.; Ruz, Marie-Hélène; Vanhée, Stéphane

    2009-04-01

    Aeolian sand transport on macrotidal beaches with complex intertidal bar-trough topography (ridge-and-runnel beaches) was assessed from experiments in northern France that involved measurements of wind speed, saltation, surface moisture contents, and rates of sand trapping across surveyed portions of the upper beach profile. Beaches exhibiting intertidal bars and troughs are much more complex, topographically, than simple reflective or dissipative beaches. Furthermore, the intertidal bar-trough morphology commonly exhibits strong cross-shore variations in the moisture contents of the beach surface and in patterns of bedform development. The results of four 30-minute experiments, conducted along topographically surveyed portions of the upper beach-dune toe profile, show that troughs act as extremely efficient sand interceptors, because of their permanently saturated state, which also inhibits sand mobilisation. Troughs, thus, limit or segment the dry fetch during conditions of intermittent saltation. Flow lines, inferred from the wind profiles, suggest that complex interactions at the boundary layer are generated by the bar-trough topography. Troughs systematically appear to be characterised by air expansion, while bar faces generate ramp wind acceleration for onshore winds, and sometimes immediate downwind deceleration for offshore winds. These effects may also contribute to cross-shore variations in the rates of sand trapping. Finally, a simple conceptual model of effective fetch development, integrating the effects of the spring-neap tidal range and of gross bar-trough morphological variability over time, is proposed for bar-trough beaches. The model highlights the key theme of fetch segmentation induced by cross-shore differentiation in the moisture contents of the beach surface hinged on the complex topography of multiple bars and troughs.

  13. The impact of lidar elevation uncertainty on mapping intertidal habitats on barrier islands

    Science.gov (United States)

    Enwright, Nicholas M.; Wang, Lei; Borchert, Sinéad M.; Day, Richard H.; Feher, Laura C.; Osland, Michael J.

    2018-01-01

    While airborne lidar data have revolutionized the spatial resolution that elevations can be realized, data limitations are often magnified in coastal settings. Researchers have found that airborne lidar can have a vertical error as high as 60 cm in densely vegetated intertidal areas. The uncertainty of digital elevation models is often left unaddressed; however, in low-relief environments, such as barrier islands, centimeter differences in elevation can affect exposure to physically demanding abiotic conditions, which greatly influence ecosystem structure and function. In this study, we used airborne lidar elevation data, in situ elevation observations, lidar metadata, and tide gauge information to delineate low-lying lands and the intertidal wetlands on Dauphin Island, a barrier island along the coast of Alabama, USA. We compared three different elevation error treatments, which included leaving error untreated and treatments that used Monte Carlo simulations to incorporate elevation vertical uncertainty using general information from lidar metadata and site-specific Real-Time Kinematic Global Position System data, respectively. To aid researchers in instances where limited information is available for error propagation, we conducted a sensitivity test to assess the effect of minor changes to error and bias. Treatment of error with site-specific observations produced the fewest omission errors, although the treatment using the lidar metadata had the most well-balanced results. The percent coverage of intertidal wetlands was increased by up to 80% when treating the vertical error of the digital elevation models. Based on the results from the sensitivity analysis, it could be reasonable to use error and positive bias values from literature for similar environments, conditions, and lidar acquisition characteristics in the event that collection of site-specific data is not feasible and information in the lidar metadata is insufficient. The methodology presented in

  14. A multilocus molecular phylogeny of combtooth blennies (Percomorpha: Blennioidei: Blenniidae): Multiple invasions of intertidal habitats

    KAUST Repository

    Hundt, Peter J.

    2014-01-01

    The combtooth blennies (f. Blenniidae) is a diverse family of primarily marine fishes with approximately 387 species that inhabit subtidal, intertidal, supralittoral habitats in tropical and warm temperate regions throughout the world. The Blenniidae has typically been divided into six groups based on morphological characters: Blenniini, Nemophini, Omobranchini, Phenablenniini, Parablenniini, and Salariini. There is, however, considerable debate over the validity of these groups and their relationships. Since little is known about the relationships in this group, other aspects of their evolutionary history, such as habitat evolution and remain unexplored. Herein, we use Bayesian and maximum likelihood analyses of four nuclear loci (ENC1, myh6, ptr, and tbr1) from 102 species, representing 41 genera, to resolve the phylogeny of the Blenniidae, determine the validity of the previously recognized groupings, and explore the evolution of habitat association using ancestral state reconstruction. Bayesian and maximum likelihood analyses of the resulting 3100. bp of DNA sequence produced nearly identical topologies, and identified many well-supported clades. Of these clades, Nemophini was the only traditionally recognized group strongly supported as monophyletic. This highly resolved and thoroughly sampled blenniid phylogeny provides strong evidence that the traditional rank-based classification does not adequately delimit monophyletic groups with the Blenniidae. This phylogeny redefines the taxonomy of the group and supports the use of 13 unranked clades for the classification of blenniids. Ancestral state reconstructions identified four independent invasions of intertidal habitats within the Blenniidae, and subsequent invasions into supralittoral and freshwater habitats from these groups. The independent invasions of intertidal habitats are likely to have played an important role in the evolutionary history of blennies. © 2013 Elsevier Inc.

  15. Carbon and nitrogen dynamics of the intertidal seagrass, Zostera japonica, on the southern coast of the Korean peninsula

    Science.gov (United States)

    Kim, Jong-Hyeob; Kim, Seung Hyeon; Kim, Young Kyun; Lee, Kun-Seop

    2016-12-01

    Seagrasses require a large amount of nutrient assimilation to support high levels of production, and thus nutrient limitation for growth often occurs in seagrass habitats. Seagrasses can take up nutrients from both the water column and sediments. However, since seagrasses inhabiting in the intertidal zones are exposed to the air during low tide, the intertidal species may exhibit significantly different carbon (C) and nitrogen (N) dynamics compared to the subtidal species. To examine C and N dynamics of the intertidal seagrass, Zostera japonica, C and N content and stable isotope ratios of above- and below-ground tissues were measured monthly at the three intertidal zones in Koje Bay on the southern coast of Korea. The C and N content and stable isotope (δ13C and δ15N) ratios of seagrass tissues exhibited significant seasonal variations. Both leaf and rhizome C content were not significantly correlated with productivity. Leaf δ13C values usually exhibited negative correlations with leaf productivity. These results of tissue C content and δ13C values suggest that photosynthesis of Z. japonica in the study site was not limited by inorganic C supply, and sufficient inorganic C was provided from the atmosphere. The tissue N content usually exhibited negative correlations with leaf productivity except at the upper intertidal zone, suggesting that Z. japonica growth was probably limited by N availability during high growing season. In the upper intertidal zone, no correlations between leaf productivity and tissue elemental content and stable isotope ratios were observed due to the severely suppressed growth caused by strong desiccation stress.

  16. Intertidal Concentrations of Microplastics and Their Influence on Ammonium Cycling as Related to the Shellfish Industry.

    Science.gov (United States)

    Cluzard, Melanie; Kazmiruk, Tamara N; Kazmiruk, Vasily D; Bendell, L I

    2015-10-01

    Microplastics are ubiquitous within the marine environment. The last 10 years have seen research directed at understanding the fate and effect of microplastics within the marine environment; however, no studies have yet addressed how concentrations of these particles could affect sedimentary processes such as nutrient cycling. Herein we first determine the concentration and spatial distribution of microplastics within Baynes Sound, a key shellfish-growing area within coastal British Columbia (BC). We also determined sediment grain size and % organic matter (OM) such that we could relate spatial patterns in sediment microplastic concentrations to sedimentary processes that determine zones of accretion and erosion. Using field-determined concentrations of microplastics, we applied laboratory microcosms studies, which manipulated sediment concentrations of microplastics, OM, and bivalves to determine the influence of sediment microplastics on ammonium cycling within intertidal sediments. Concentrations of microplastics determined within the intertidal sediment varied spatially and were similar to those found in other coastal regions of high urban use. Concentrations were independent of grain size and OM suggesting that physical processes other than those that govern natural sediment components determine the fate of microplastics within sediments. Under laboratory conditions, concentrations of ammonium were significantly greater in the overlying water of treatments with microplastics, clams, and OM compared with treatments without microplastics. These preliminary studies suggest that high concentrations of microplastics have the potential to alter key sedimentary processes such as ammonium flux. This could have serious implications, for example, contributing to eutrophication events in regions of the coast that are highly urbanized.

  17. Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

    Science.gov (United States)

    Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K.A.S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D.G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O’Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J.A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

    2016-01-01

    At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10–30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0–2.5 °C, during daily fluctuations that often exceeded 15°–20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature. PMID:27727238

  18. Rocky intertidal macrobenthic communities across a large-scale estuarine gradient

    Directory of Open Access Journals (Sweden)

    Luis Giménez

    2010-03-01

    Full Text Available We evaluated relationships between (1 salinity and species richness and (2 frontal zones and community structure for the rocky intertidal macrobenthic community of the Uruguayan coast. A large-scale sampling design (extent ~500 km covering 9 rocky shores across 3 intertidal levels was performed between September and November 2002. The linear relationship between salinity and species richness (minimum at the freshwater extreme and the lack of correlation between variation in salinity and richness rejected two previous empirical models, explaining variations in species richness along the salinity gradient. Other factors (e.g. turbidity may explain this discrepancy. The estuarine front defined two communities—freshwater and estuarine-marine—differing in species composition and richness. The freshwater community was characterised by low richness and few individuals confined to crevices or tide pools, and must be structured by physical processes (e.g. desiccation; the estuarine-marine community, with individuals occupying almost all available substrata, must be structured by both physical and biological processes. A marine front, separating estuarine and marine habitats, had a weak effect on community structure although estuarine and marine assemblages differed according to species characterising different functional groups. We conclude that the position of the estuarine frontal zones is important for explaining large-scale patterns of community structure in the study area.

  19. Hidden in the mangrove forest: the cryptic intertidal mite Carinozetes mangrovi sp. nov. (Acari, Oribatida, Selenoribatidae).

    Science.gov (United States)

    Pfingstl, Tobias; Lienhard, Andrea; Jagersbacher-Baumann, Julia

    2014-08-01

    The small archipelago of Bermuda is a geologically young landmass in the Western Atlantic Ocean and recently turned out to be inhabited by a number of intertidal oribatid mites. One newly described species, Carinozetes bermudensis, showed an unusual vast range of habitats like sandy beaches, rocky substrate and mangroves. In the present study, 13 Bermudian populations of C. bermudensis were analysed to verify species integrity of specimens from different microhabitats. A morphometric analysis of 17 continuous variables as well as a molecular genetic investigation of the mitochondrial cytochrome oxidase subunit I revealed the existence of a new species Carinozetes mangrovi sp. nov., inhabiting exclusively intertidal algae growing on mangrove roots. Although both species are morphologically nearly identical, the configuration of the genus-specific ventral carinae represents a clear diagnostic character. The high genetic divergence of approximately 12 % of the cytochrome oxidase subunit I gene sequence between C. bermudensis and C. mangrovi sp. nov. suggests that these two species diverged before the emergence of the Bermuda islands. Accordingly, both of them are older than the geologically young archipelago of Bermuda.

  20. Organic carbon burial in a mangrove forest, margin and intertidal mud flat

    Science.gov (United States)

    Sanders, Christian J.; Smoak, Joseph M.; Naidu, A. Sathy; Sanders, Luciana M.; Patchineelam, Sambasiva R.

    2010-12-01

    The flux of total organic carbon (TOC) to depositional facies (intertidal mud flat, margin and forest) was quantified for a tropical mangrove forest in Brazil. Results indicate that these mangrove margins and intertidal mudflats are sites of large TOC accumulation, almost four times greater than the global averages for mangrove forests. The TOC burial rates were determined from organic carbon content in sediment cores which were dated using 210Pb. Burial rates were calculated to be 1129, 949, and 353 (g m -2 yr -1), for the mud flat, margin and forest, respectively. Sediment accumulation rates (SAR) were estimated to be 7.3, 5.0 and 2.8 mm yr -1. Sediment characterization (δ 13C, δ 15N, TOC/TN and mud fraction) indicated a representative mangrove system with a record of consistent organic matter flux of up to 100 years. Because of substantial burial of organic carbon in mangrove ecosystems, their role in the global carbon budget must be considered. More importantly, as climate change influences temperature and sea level, mangrove ecosystems will respond to specific climatic conditions.

  1. Heavy metal contamination in surface sediments of Yangtze River intertidal zone: An assessment from different indexes

    International Nuclear Information System (INIS)

    Zhang Weiguo; Feng Huan; Chang Jinna; Qu Jianguo; Xie Hongxia; Yu Lizhong

    2009-01-01

    Surface sediments (0-5 cm) from 59 stations within the Yangtze River intertidal zone (YRIZ) were sampled for metal contamination analysis in April and August 2005. The concentrations ranged (in mg kg -1 dry weight): Al, 40,803-97,213; Fe, 20,538-49,627; Cd, 0.12-0.75; Cr, 36.9-173; Cu, 6.87-49.7; Mn, 413-1,112; Ni, 17.6-48.0; Pb, 18.3-44.1; and Zn, 47.6-154; respectively. Among the 59 sampling stations, enrichment factors (EF) indicate enrichment of Cd (52 stations), Cr (54 stations), Cu (5 stations), Ni (26 stations), Pb (5 stations) and Zn (5 stations). Geoaccumulation indexes (I geo ) also suggest individual metal contamination in localized areas. This study indicates that Cd, Cr and Ni enrichment in the YRIZ sediment is widespread whereas Cu, Mn, Pb and Zn enrichment is localized or nonexistent. Factor and cluster analyses indicate that Cd is associated with total organic carbon whereas Cu, Cr, Ni, Pb and Zn have a close association with Mn. - Surface sediment metal enrichment is evidenced for Cd, Cr and Ni in the Yangtze River intertidal zone.

  2. Emersion induces nitrogen release and alteration of nitrogen metabolism in the intertidal genus Porphyra.

    Directory of Open Access Journals (Sweden)

    Jang K Kim

    Full Text Available We investigated emersion-induced nitrogen (N release from Porphyra umbilicalis Kütz. Thallus N concentration decreased during 4 h of emersion. Tissue N and soluble protein contents of P. umbilicalis were positively correlated and decreased during emersion. Growth of P. umbilicalis did not simply dilute the pre-emersion tissue N concentration. Rather, N was lost from tissues during emersion. We hypothesize that emersion-induced N release occurs when proteins are catabolized. While the δ(15N value of tissues exposed to emersion was higher than that of continuously submerged tissues, further discrimination of stable N isotopes did not occur during the 4 h emersion. We conclude that N release from Porphyra during emersion did not result from bacterial denitrification, but possibly as a consequence of photorespiration. The release of N by P. umbilicalis into the environment during emersion suggests a novel role of intertidal seaweeds in the global N cycle. Emersion also altered the physiological function (nitrate uptake, nitrate reductase and glutamine synthetase activity, growth rate of P. umbilicalis and the co-occurring upper intertidal species P. linearis Grev., though in a seasonally influenced manner. Individuals of the year round perennial species P. umbilicalis were more tolerant of emersion than ephemeral, cold temperate P. linearis in early winter. However, the mid-winter populations of both P. linearis and P. umbilicalis, had similar temporal physiological patterns during emersion.

  3. Temporal variation of intertidal seagrass in southern China (2008-2014)

    Science.gov (United States)

    Qiu, Guanglong; Short, Frederick T.; Fan, Hangqing; Liu, Guohua

    2017-09-01

    Understanding the temporal dynamics of seagrasses and the major influences on seagrass growth is critical for seagrass habitat conservation and administration. However, little work has been done regarding these issues in southern China. To examine inter-annual and seasonal variations of the intertidal Halophila ovalis community in southern China, we conducted quarterly sampling using the SeagrassNet methodology and assessed environmental conditions as well as direct anthropogenic impacts on the seagrass meadow from July 2008 to October 2014. Our study demonstrated strong inter-annual and seasonal dynamics of the intertidal seagrass meadow in the study area. Generally, the community performed best (highest seagrass cover, leaf area, shoot density, total biomass) in summer and worst in spring among the 4 seasons. The temporal variations in the seagrass community attributes (e.g. above-ground biomass) were significantly affected by precipitation, atmospheric visibility, and salinity, while leaf width was significantly negatively correlated with temperature, atmospheric visibility and salinity. Temperature was a major factor influencing the seagrass community (both macroalgae and seagrass), with temperature data showing an inverse relationship between seagrass and macroalgae. The above-ground: below-ground biomass ratio and leaf width of H. ovalis were the most sensitive plant parameters monitored when assessing environmental interactions. Human physical disturbances did not have a significant effect on seagrass dynamics in the study area. We concluded that long-term monitoring (like SeagrassNet) is valuable in understanding the relationship between environmental variables and seagrasses.

  4. Restoring rocky intertidal communities: Lessons from a benthic macroalgal ecosystem engineer

    International Nuclear Information System (INIS)

    Bellgrove, Alecia; McKenzie, Prudence F.; Cameron, Hayley; Pocklington, Jacqueline B.

    2017-01-01

    As coastal population growth increases globally, effective waste management practices are required to protect biodiversity. Water authorities are under increasing pressure to reduce the impact of sewage effluent discharged into the coastal environment and restore disturbed ecosystems. We review the role of benthic macroalgae as ecosystem engineers and focus particularly on the temperate Australasian fucoid Hormosira banksii as a case study for rocky intertidal restoration efforts. Research focussing on the roles of ecosystem engineers is lagging behind restoration research of ecosystem engineers. As such, management decisions are being made without a sound understanding of the ecology of ecosystem engineers. For successful restoration of rocky intertidal shores it is important that we assess the thresholds of engineering traits (discussed herein) and the environmental conditions under which they are important. - Highlights: • Fucoid algae can be important ecosystem engineers in rocky reef ecosystems • Sewage-effluent disposal negatively affects fucoids and associated communities • Restoring fucoid populations can improve biodiversity of degraded systems • Clarifying the roles of fucoids in ecosystem function can improve restoration efforts • Thresholds of engineering traits and associated environmental conditions important

  5. Temporal distribution of intertidal macrozoobenthic assemblages in a Nanozostera noltii-dominated area (Lagoon of Venice).

    Science.gov (United States)

    Tagliapietra, D; Pessa, G; Cornello, M; Zitelli, A; Magni, P

    2016-03-01

    We describe the temporal distribution of intertidal macrozoobenthic assemblages in a small marsh pond of the Lagoon of Venice colonized by the seagrass Nanozostera noltii (Hornemman) Tomlinson et Posluzny. Three stations ranging in the degree of N. noltii cover were selected about 100 m apart and sampled 9 times at regular intervals from March 1996 to March 1997. We applied the concepts of resistance and resilience to "natural stress" (e.g. extent of protection from seagrass meadows, exposure of macrozoobenthic assemblages to high temperatures in summer) with the aim to assess the stability of a community along a gradient of seagrass coverage. Results showed that the most structured and taxa-rich macrozoobenthic assemblage occurred at the station covered by a continuous stand of N. noltii, where permanent taxa (i.e. found in 100% of samples) were almost double than those found at the other stations. During the annual cycle, the macrozoobenthic assemblages showed a cyclical pattern, with temporal fluctuations increasing as they moved further away from the seagrass beds. We propose the role of N. noltii offering structural complexity and stability as the more probable explanation to the observed differences between stations in the intertidal assemblages. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Interaction between birds and macrofauna within food webs of six intertidal habitats of the Wadden Sea.

    Science.gov (United States)

    Horn, Sabine; de la Vega, Camille; Asmus, Ragnhild; Schwemmer, Philipp; Enners, Leonie; Garthe, Stefan; Binder, Kirsten; Asmus, Harald

    2017-01-01

    The determination of food web structures using Ecological Network Analysis (ENA) is a helpful tool to get insight into complex ecosystem processes. The intertidal area of the Wadden Sea is structured into diverse habitat types which differ in their ecological functioning. In the present study, six different intertidal habitats (i.e. cockle field, razor clam field, mud flat, mussel bank, sand flat and seagrass meadow) were analyzed using ENA to determine similarities and characteristic differences in the food web structure of the systems. All six systems were well balanced between their degree of organization and their robustness. However, they differed in their detailed features. The cockle field and the mussel bank exhibited a strong dependency on external imports. The razor clam field appeared to be a rather small system with low energy transfer. In the mud flat microphytobenthos was used as a main food source and the system appeared to be sensitive to perturbations. Bird predation was the most pronounced in the sand flat and the seagrass meadow and led to an increase in energy transfer and parallel trophic cycles in these habitats. Habitat diversity appears to be an important trait for the Wadden Sea as each subsystem seems to have a specific role in the overall functioning of the entire ecosystem.

  7. The role of ecological divergence in speciation between intertidal and subtidal Scoloplos armiger (Polychaeta, Orbiniidae)

    Science.gov (United States)

    Kruse, Inken; Strasser, Matthias; Thiermann, Frank

    2004-02-01

    The concept of ecological speciation implies that habitat differences may split a species by strong selection and rapid adaptation even under sympatric conditions. Studies on the polychaete Scoloplos armiger in the Wadden Sea (North Sea) indicate sibling species existing in sympatry: the intertidal 'Type I' with holobenthic development out of egg cocoons and the subtidal 'Type S' producing pelagic larvae. In the current study, Types I and S are compared in habitat-related traits of reproductive timing and physiological response to hypoxia and sulphide. Spawnings of Type I and Type S recorded over six years overlap in spring and both appear to be triggered by a rise in seawater temperature above 5 °C. Type S exhibits an additional autumn spawning (at seawater temperatures around 10 °C) which was previously unknown and is absent in Type I. The overall abundance of pelagic larvae in the Wadden Sea is higher in spring than in autumn. Tolerance of both sulphide and hypoxia was lower in Type S than in Type I. This correlates with a 5 to 10-fold lower sulphide concentration in the subtidal compared to the intertidal habitat. Physiological tolerance and divergence in developmental mode appear as traits which may have led to reproductive isolation between Type I and Type S. Their role in allopatric and sympatric speciation scenarios in S. armiger is discussed. Since the pelagic dispersal mode has been neglected so far, a reassessment of population dynamics models for S. armiger is suggested.

  8. Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

    International Nuclear Information System (INIS)

    Liu, M. . E-mail mliu@geo.ecnu.edu.cn; Hou, L.J.; Xu, S.Y.; Ou, D.N.; Yang, Y.; Yu, J.; Wang, Q.

    2006-01-01

    The natural isotopic compositions and C/N elemental ratios of sedimentary organic matter were determined in the intertidal flat of the Yangtze Estuary. The results showed that the ratios of carbon and nitrogen stable isotopes were respectively -29.8 per mille to - 26.0 per mille and 1.6 per mille -5.5 per mille in the flood season (July), while they were -27.3 per mille to - 25.6 per mille and 1.7 per mille -7.8 per mille in the dry season (February), respectively. The δ 13 C signatures were remarkably higher in July than in February, and gradually increased from the freshwater areas to the brackish areas. In contrast, there were relatively complex seasonal and spatial changes in stable nitrogen isotopes. It was also reflected that δ 15 N and C/N compositions had been obviously modified by organic matter diagenesis and biological processing, and could not be used to trace the sources of organic matter at the study area. In addition, it was considered that the mixing inputs of terrigenous and marine materials generally dominated sedimentary organic matter in the intertidal flat. The contribution of terrigenous inputs to sedimentary organic matter was roughly estimated according to the mixing balance model of stable carbon isotopes

  9. Metabolic regulatory oscillations in intertidal green seaweed Ulva lactuca against tidal cycles.

    Science.gov (United States)

    Gupta, Vishal; Kushwaha, Hemant R

    2017-11-27

    The survival of wetland plant species largely relies on physiological adaptations essential for submergence and desiccation. Intertidal seaweeds, unlike terrestrial plants, have unique adaptations to submergence and can also sustain desiccation arising from tidal rhythms. This study determined the differential metabolic regulations in the inter-tidal seaweed species Ulva lactuca against the submergence and desiccation. During desiccation, the relative water content of the algal thalli declined with concomitant increase in reactive oxygen species (ROS) and lipid peroxidation. Nevertheless, the trends reversed during recovery on re-submergence and attained homeostasis. Metabolite profiling of U. lactuca revealed desiccation induced balance in energy reserve utilization by adjusting carbohydrate metabolism and switch over to ammonia metabolism. Upon re-submergence, thalli showed an increase in fermentative metabolites, pyruvate-alanine conversion, and the GABA shunt. Prolonged submergence induced substrate level phosphorylation mediated sugar biosynthesis while continuing the alternative carbon flux through fermentative metabolism, an increase in osmoprotectants glycine and betaine, sulfur bearing compounds cysteine and hypotaurine, and phenolic compound coniferaldehyde. The determined metabolic regulations in U. lactuca for submergence tolerance provide insights into potential evolutionarily conserved protective mechanisms across the green lineage and also highlights the possible role of sulfur oxoforms as strong free radical scavengers.

  10. Impacts of macro - and microplastic on macrozoobenthos abundance in intertidal zone

    Science.gov (United States)

    Bangun, A. P.; Wahyuningsih, H.; Muhtadi, A.

    2018-02-01

    Plastics pollution in coastal areas is one of the topics that have received more attention over the past few years. The intertidal zone is a waters area that is directly affected by contamination of plastic waste from land and sea. The purpose of this study was to analyze the types and abundance of plastic waste in the intertidal zone and its impact on macrozoobenthos abundance. This research was conducted at Pesisir Desa Jaring Halus in February-April 2017. Macrozoobenthos and macro - micro plastic were collected by using quadratic transect. Sediments were collected with a core, to a depth of 30 cm. Microplastic and macroplastic abundances were analyzed using separation of sediment density and hand sorting. The dominant micro plastic types were film (52.30%), fiber (24.88%), fragments (22.74%), followed by pellets (0.1%). The total number of microplastics were 326,33 items and macro plastic were 308 items. Macroplastic abundance is positively correlated with microplastic (0.765). The abundance of macrozoobenthos is negatively correlated with microplastic abundance (-0.368) and with macro plastic abundance (-0.633). The management strategies were suggested clean up marine debris, decrease plastic using and built up the station of debris processing.

  11. Trophic and stoichiometric consequences of nutrification for the intertidal tropical zoanthid Zoanthus sociatus.

    Science.gov (United States)

    Leal, Miguel C; Rocha, Rui J M; Anaya-Rojas, Jaime M; Cruz, Igor C S; Ferrier-Pagès, Christine

    2017-06-15

    Zoanthids are conspicuous and abundant members of intertidal environments, where they are exposed to large environmental fluctuations and subject to increasing loads of anthropogenic nutrients. Here we assess the trophic ecology and stoichiometric consequences of nutrient loading for symbiotic zoanthids inhabiting different intertidal habitats. More specifically, we analysed the stable isotope signature (δ 13 C and δ 15 N), elemental composition (C, N and P) and stoichiometry (C:N, C:P, N:P) of Zoanthus sociatus differently exposed to nutrification. Results suggest that autotrophy is the main feeding mode of zoanthids and that the effect water nutrient content differently affects the elemental phenotype of zoanthids depending on tidal habitat. Additionally, habitat effects on Z. sociatus P-related stoichiometric traits highlight functional differences likely associated with variation in Symbiodinium density. These findings provide an innovative approach to assess how cnidarian-dinoflagellate symbioses response to ecosystem changes in environmentally dynamic reef flats, particularly nutrient loading. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Adaptive shell color plasticity during the early ontogeny of an intertidal keystone snail.

    Science.gov (United States)

    Manríquez, Patricio H; Lagos, Nelson A; Jara, María Elisa; Castilla, Juan Carlos

    2009-09-22

    We report a mechanism of crypsis present during the vulnerable early post-metamorphic ontogeny (Concholepas concholepas, a rocky shore keystone predator characteristic of the southeastern Pacific coast. In the field, we found a significant occurrence (>95%) of specimens bearing patterns of shell coloration (dark or light colored) that matched the background coloration provided by patches of Concholepas' most abundant prey (mussels or barnacles respectively). The variation in shell color was positively associated with the color of the most common prey (r = 0.99). In laboratory experiments, shell coloration of C. concholepas depended on the prey-substrate used to induce metamorphosis and for the post-metamorphic rearing. The snail shell color matched the color of the prey offered during rearing. Laboratory manipulation experiments, switching the prey during rearing, showed a corresponding change in snail shell color along the outermost shell edge. As individuals grew and became increasingly indistinguishable from the surrounding background, cryptic individuals had higher survival (71%) than the non cryptic ones (4%) when they were reared in the presence of the predatory crab Acanthocyclus hassleri. These results suggest that the evolution of shell color plasticity during the early ontogeny of C. concholepas, depends on the color of the more abundant of the consumed prey available in the natural habitat where settlement has taken place; this in turn has important consequences for their fitness and survivorship in the presence of visual predators.

  13. Microbial community of cyanobacteria mats in the intertidal zone of oil-polluted coast of Saudi Arabia.

    Science.gov (United States)

    Al-Thukair, A A; Abed, R M M; Mohamed, L

    2007-02-01

    Cyanobacterial mats are found at various locations along the coast of the Eastern Province of Saudi Arabia. Those mats were affected by severe oil pollution following 1991 oil spill. In this study, samples from Abu Ali Island were collected at three selected sampling sites across the intertidal zone (Lower, Middle, and Upper) in order to understand the effect of extreme environmental conditions of high salinity, temperature and desiccation on distribution of cyanobacteria along the oil polluted intertidal zone. Our investigation of composition of cyanobacteria and diatoms was carried out using light microscopy, and Denaturant Gradient Gel Electrophoresis (DGGE) technique. Light microscopy identification revealed dominant cyanobacteria to be affiliated with genera Phormidium, Microcoleus, and Schizothrix, and to a lesser extent with Oscillatoria, Halothece, and various diatom species. The analysis of DGGE of PCR-amplified 16S rRNA fragments showed that the diversity of cyanobacteria decreases as we proceed from the lower to the upper intertidal zone. Accordingly, the tidal regime, salinity, elevated ambient air temperature, and desiccation periods have a great influence on the distribution of cyanobacterial community in the oil polluted intertidal zone of Abu Ali Island.

  14. ENVIRONMENTAL-EFFECTS ON THE GROWTH-RATE OF INTERTIDAL INVERTEBRATES AND SOME IMPLICATIONS FOR FORAGING WADERS

    NARCIS (Netherlands)

    WANINK, JH; ZWARTS, L

    1993-01-01

    The paper describes effects of intertidal height and sediment type on growth rate of the bivalves Cerastoderma edule, Macoma balthica, Mya arenaria, Mytilus edulis and Scrobicularia plana, and of the worms Arenicola marina, Nephtys hombergii and Nereis diversicolor in the eastern part of the Dutch

  15. Effect of salinity on nitrogenase activity and composition of the active diazotrophic community in intertidal microbial mats

    NARCIS (Netherlands)

    Severin, I.; Confurius-Guns, V.; Stal, L.J.

    2012-01-01

    Microbial mats are often found in intertidal areas experiencing a large range of salinities. This study investigated the effect of changing salinities on nitrogenase activity and on the composition of the active diazotrophic community ( transcript libraries) of three types of microbial mats situated

  16. Trophic linkage of a temperate intertidal macrobenthic food web under opportunistic macroalgal blooms: A stable isotope approach

    International Nuclear Information System (INIS)

    Park, Hyun Je; Han, Eunah; Lee, Young-Jae; Kang, Chang-Keun

    2016-01-01

    The effects of blooms of opportunistic green macroalgae, Ulva prolifera, on the trophic structure of the macrobenthic food web in a temperate intertidal zone on the western coast of Korea were evaluated using carbon and nitrogen stable isotopes. Biomasses of Ulva and microphytobenthos (MPB) increased significantly at the macroalgae-bloom and the non-bloom sites, respectively, from March to September 2011. The δ 13 C values of most the consumers were arrayed between those of MPB and Ulva at both sites, and differed according to feeding strategies at the macroalgae-bloom site. Seasonally increasing magnitudes in δ 13 C and δ 15 N values of consumers were much steeper at the macroalgae-bloom site than at the non-bloom site. Our findings provide evidence that blooming green macroalgae play a significant role as a basal resource supporting the intertidal macrobenthic food web and their significance varies with feeding strategies of consumers as well as the resource availability. - Highlights: • Trophic effects of Ulva blooms on intertidal macrobenthic food web were evaluated. • Biomasses of Ulva increased at the macroalgae-bloom from March to September. • δ 13 C and δ 15 N values of consumers differed with feeding strategy and season. • Trophic significance of blooming macroalgae varies with feeding strategies of consumers. • Ulva blooms play a significant role as a basal resource supporting the intertidal food web.

  17. Studies of environmental radioactivity in Cumbria. Pt. 8. Plutonium and americium in the intertidal sands of North-West England

    Energy Technology Data Exchange (ETDEWEB)

    Eakins, J.D.; Morgan, A.; Baston, G.M.N.; Pratley, F.A.; Yarnold, L.P.; Burton, P.J.

    1988-03-01

    Sand cores and surface sand samples have been collected from the sea-facing intertidal regions of West Cumbria, between Silloth and Walney Island. Sand cores were also taken from the Duddon estuary and Morecambe Bay. The samples were collected between June 1983 and March 1984 and have been analysed for /sup 238/Pu, /sup 239+240/Pu and /sup 241/Am. The integrated deposits of /sup 239+240/Pu and /sup 241/Am in intertidal sand between Silloth and Walney Island were about 4.2 and 7 TBq respectively. Combined, this represents about 1% of the total alpha-emitting actinide activity discharged from Sellafield to sea up to 1982; the corresponding value for the Duddon Estuary is about 0.3%. The actinide levels observed are compared to those of natural alpha emitters in intertidal sand. Only on beaches close to Sellafield did levels of discharged alpha emitters exceed those of natural alpha-emitting nuclides. In the vicinity of Sellafield, the annual dose to man from the inhalation of resuspended intertidal material is certainly less than 50 ..mu..Sv (committed effective dose equivalent) and may be substantially lower.

  18. Fortuynia marina nov. gen., nov. spec., an Oribatid mite from the intertidal zone in Netherlands New Guinea

    NARCIS (Netherlands)

    Hammen, van der L.

    1960-01-01

    On December 7, 1953, while collecting animals along the south coast of Biak Island (Netherlands New Guinea), in the neighbourhood of the Base of the Royal Netherlands Navy 1), I was surprised in seeing red Trombidiid mites creeping on stones in the intertidal zone. These stones, which fall dry at

  19. The role of shore crabs and mussel density in mussel losses at a commercial intertidal mussel plot after seeding

    NARCIS (Netherlands)

    Capelle, Jacob J.; Scheiberlich, Gerard; Wijsman, Jeroen W.M.; Smaal, Aad C.

    2016-01-01

    Mussel losses peak after relaying seed on culture plots. The present paper is an attempt to examine the role of shore crab predation and initial mussel density on mussel losses in mussel bottom culture using an intertidal culture plot as a case study. Because of their small size and loose

  20. Computing Risk to West Coast Intertidal Rocky Habitat due to Sea Level Rise using LiDAR Topobathy

    Science.gov (United States)

    Compared to marshes, little information is available on the potential for rocky intertidal habitats to migrate upward in response to sea level rise (SLR). To address this gap, we utilized topobathy LiDAR digital elevation models (DEMs) downloaded from NOAA’s Digital Coast G...

  1. Tracing carbon flow from microphytobenthos to major bacterial groups in an intertidal marine sediment by using an in situ

    NARCIS (Netherlands)

    Miyatake, T.; Moerdijk-Poortvliet, T.C.W.; Stal, L.J.; Boschker, H.T.S.

    2014-01-01

    Carbon flow from benthic diatoms to heterotrophic bacterial was traced in an intertidal sediment for 5consecutive days. 13C-labeled bicarbonate was sprayed onto the sediment surface during low tide and 13C-labelincorporation in major carbon pools, intermediate metabolites, and biomarkers were

  2. The Role of Water Movement and Spatial Scaling for Measurement of Dissolved Inorganic Nitrogen Fluxes in Intertidal Sediments

    Science.gov (United States)

    Asmus, R. M.; Jensen, M. H.; Jensen, K. M.; Kristensen, E.; Asmus, H.; Wille, A.

    1998-02-01

    Fluxes of dissolved inorganic nitrogen (ammonium and nitrate) across the sediment-water interface were determined at intertidal locations in Königshafen, northern Wadden Sea, North Sea. Three different incubation techniques were compared: closed sediment cores (small scale), closed bell jars (medium scale) and an open flow system (Sylt flume, large scale). Water movement in the two closed systems was maintained below the resuspension limit by spinning magnets (cores, incubated in the laboratory) or by transfer of wave action through flexible plastic foil (bell jars,in situ), whereas in the flume system (in situ) water movement was unidirectional, driven by currents and waves. Data sets from several years of core measurements (1992-94), bell jar measurements (1980) and flume campaigns (1990-93) served as the basis for a comparison of dissolved inorganic nitrogen fluxes. Fluxes of ammonium and nitrate were within the same order of magnitude in closed cores and bell jars, while flume rates of ammonium were considerably higher. The high flume rates were caused by advective flushing due to tidal water movement and wave action. The release of ammonium increased significantly with current velocity between 1 and 13 cm s-1. Fluxes of ammonium were higher in sediments withArenicola marinacompared to those without this bioturbating species. The influence of benthic microalgae was evident only in the small and medium scale core and bell jar systems as reduced ammonium release during light exposure. Nitrate was consumed by sediments in both closed systems at a rate proportional to the nitrate concentration in the overlying water. Nitrate fluxes in the large scale Sylt flume were low with an average of only 7% of the ammonium fluxes, probably due to low concentrations in tidal waters during measurements (summer). Both closed, small scale or open, large scale techniques can be applied successfully for benthic flux studies, but the actual choice depends on the purpose of the

  3. Transcription, Signaling Receptor Activity, Oxidative Phosphorylation, and Fatty Acid Metabolism Mediate the Presence of Closely Related Species in Distinct Intertidal and Cold-Seep Habitats.

    Science.gov (United States)

    Van Campenhout, Jelle; Vanreusel, Ann; Van Belleghem, Steven; Derycke, Sofie

    2015-12-03

    Bathyal cold seeps are isolated extreme deep-sea environments characterized by low species diversity while biomass can be high. The Håkon Mosby mud volcano (Barents Sea, 1,280 m) is a rather stable chemosynthetic driven habitat characterized by prominent surface bacterial mats with high sulfide concentrations and low oxygen levels. Here, the nematode Halomonhystera hermesi thrives in high abundances (11,000 individuals 10 cm(-2)). Halomonhystera hermesi is a member of the intertidal Halomonhystera disjuncta species complex that includes five cryptic species (GD1-5). GD1-5's common habitat is characterized by strong environmental fluctuations. Here, we compared the transcriptomes of H. hermesi and GD1, H. hermesi's closest relative. Genes encoding proteins involved in oxidative phosphorylation are more strongly expressed in H. hermesi than in GD1, and many genes were only observed in H. hermesi while being completely absent in GD1. Both observations could in part be attributed to high sulfide concentrations and low oxygen levels. Additionally, fatty acid elongation was also prominent in H. hermesi confirming the importance of highly unsaturated fatty acids in this species. Significant higher amounts of transcription factors and genes involved in signaling receptor activity were observed in GD1 (many of which were completely absent in H. hermesi), allowing fast signaling and transcriptional reprogramming which can mediate survival in dynamic intertidal environments. GC content was approximately 8% higher in H. hermesi coding unigenes resulting in differential codon usage between both species and a higher proportion of amino acids with GC-rich codons in H. hermesi. In general our results showed that most pathways were active in both environments and that only three genes are under natural selection. This indicates that also plasticity should be taken in consideration in the evolutionary history of Halomonhystera species. Such plasticity, as well as possible

  4. An evaluation of intertidal feeding habitats from a shorebird perspective: Towards relevant comparisons between temperate and tropical mudflats

    Science.gov (United States)

    Piersma, Theunis; de Goeij, Petra; Tulp, Ingrid

    Macrozoobenthic communities of intertidal soft sediments are reviewed worldwide from the perspective of a mollusc-eating shorebird species. Based on 19 sites, total biomass figures varied between 5 and 80 g AFDM per m 2 (average 24 g AFDM per m 2); no latitudinal trends are apparent. The contribution made by bivalves and gastropods varies between 1% and 99%, north-temperate intertidal flats having relatively more molluscs than tropical flats. Intertidal flats in the tropics contain a greater variety of taxa, with brachiopods in Indonesia and echinoderms in northwest Australia contributing significantly to biomass only there. Limits to the occurrence of avian predators of intertidal benthos are set by the harvestable fraction of the biomass on offer and the costs of living at a particular site. No systematic differences in the harvestable fraction of the total mollusc-biomass for a worldwide occurring shorebird species specializing on molluscs (knots Calidris canutus) were apparent between temperate and tropical intertidal areas, in spite of large differences in maintenance metabolism incurred by these birds. The harvestable fractions of bivalves in the two West African areas (Banc d'Arguin, Mauritania and Guinea-Bissau) tended to be high (23-84% of total biomass in six species), they were relatively low (2-52% in five species) in the temperate Wadden Sea and the tropical northwest Australian site. Harvestable biomass determines the intake rate of shorebirds, as illustrated by functional-response curves of knots feeding on two bivalves species. We argue that the collection of information on size-depth relationships along with faunal and biomass surveys at a range of sites is bound to greatly increase our understanding of both the biology of tidal-flat invertebrates and the resource base underpinning the spectacular seasonal migrations of shorebirds.

  5. vasa-related genes and their expression in stem cells of colonial parasitic rhizocephalan barnacle Polyascus polygenea (Arthropoda: Crustacea: Cirripedia: Rhizocephala).

    Science.gov (United States)

    Shukalyuk, Andrey I; Golovnina, Kseniya A; Baiborodin, Sergei I; Gunbin, Konstantin V; Blinov, Alexander G; Isaeva, Valeria V

    2007-02-01

    vasa (vas)-related genes are members of the DEAD-box protein family and are expressed in the germ cells of many Metazoa. We cloned vasa-related genes (PpVLG, CpVLG) and other DEAD-box family related genes (PpDRH1, PpDRH2, CpDRH, AtDRHr) from the colonial parasitic rhizocephalan barnacle Polyascus polygenea, the non-colonial Clistosaccus paguri (Crustacea: Cirripedia: Rhizocephala), and the parasitic isopodan Athelgis takanoshimensis (Crustacea: Isopoda). The colonial Polyascus polygenea, a parasite of the coastal crabs Hemigrapsus sanguineus and Hemigrapsus longitarsis was used as a model object for further detailed investigations. Phylogenetic analysis suggested that PpVLG and CpVLG are closely related to vasa-like genes of other Arthropoda. The rest of the studied genes form their own separate branch on the phylogenetic tree and have a common ancestry with the p68 and PL10 subfamilies. We suppose this group may be a new subfamily of the DEAD-box RNA helicases that is specific for parasitic Crustacea. We found PpVLG and PpDRH1 expression products in stem cells from stolons and buds of internae, during asexual reproduction of colonial P. polygenea, and in germ cells from sexually reproducing externae, including male spermatogenic cells and female oogenic cells.

  6. PROPORTIONS AND HUMAN SCALE IN DAMASCENE COURTYARD HOUSES

    Directory of Open Access Journals (Sweden)

    M. Salim Ferwati

    2008-03-01

    Full Text Available Interior designers, architects, landscape architects, and even urban designers, agree that environment, as a form of non-verbal communication means, has a symbolic dimension to it. As for its aesthetic dimension, it seems that beauty is related to a certain proportion, partially and as a whole. Suitable proportion leaves a good impression upon the beholders, especially when it matches human proportion. That in fact was the underlining belief of LeCorbusier, according to which he developed his Modular concept. The study searches for a modular, or proportion, system that governs the design of Damascene traditional house. By geometrical and mathematical examinations of 28 traditional houses, it was found that a certain proportional relationship existed; however, these proportional relationships were not fixed ones. The study relied on analyzing the Iwan elevation as well as the inner courtyard proportion in relation to the building area. Charts, diagrams and tables were produced to summarize the results.

  7. Characterization of an estuarine environment by means of an index based on intertidal macrofauna.

    Science.gov (United States)

    Conde, Anxo; Novais, Júlio M; Domínguez, Jorge

    2013-06-15

    Macrobenthic intertidal assemblages from five Atlantic Iberian estuaries were analyzed to develop an estuarine index. An R-mode analysis revealed a close association between the isopod Cyathura carinata, the polychaete Hediste diversicolor and the bivalve Scrobicularia plana. Although these species are abundant in all the estuaries considered, they tend to be absent from sites at the marine and freshwater ends of the environmental gradient. Three different ways of calculating the estuarine index are proposed. The index is comprised in the interval [0,1] and was constructed using relative abundances rather than absolute abundances. Transformation of the raw data helped improve the performance of the index. A non-parametric statistical test is proposed for application to the estuarine index to find sites with the same values after a significant omnibus test. The index appears to be a good proxy for recognizing estuarine limits by use of indicator species. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Is the feeding type related with the content of microplastics in intertidal fish gut?

    Science.gov (United States)

    Mizraji, Ricardo; Ahrendt, Camila; Perez-Venegas, Diego; Vargas, Juan; Pulgar, Jose; Aldana, Marcela; Patricio Ojeda, F; Duarte, Cristian; Galbán-Malagón, Cristobal

    2017-03-15

    Microplastics pollution is a growing global concern that affects all aquatic ecosystems. Microplastics in the environment can be in the form of fibers and/or particles, being the former the most abundant in the marine environment, representing up to 95% of total plastics. The aim of this work was to compare the content of microplastics among intertidal fish with different feeding type. Our results show that omnivorous fish presented a higher amount of microplastic fibers than registered in herbivores and carnivores. Moreover, lower condition factors (K) were found in omnivorous specimens with higher microplastic content. We hypothesized that the type of feeding resulted in different microplastic ingestion, with species with wider range of food sources as omnivores with higher rates. Futures studies carried out to evaluate the biological impacts of microplastics on marine organisms, and microplastics cycling on the marine environment should consider the type of feeding of the studied species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Sulfur isotope study of a modern intertidal environment, and the interpretation of ancient sulfides

    International Nuclear Information System (INIS)

    Chambers, L.A.

    1982-01-01

    Extensive sulfur isotope distribution data for sulfides precipitated in an intertidal environment show no distinctive features when compared with isotope values for other marine, sedimentary sulfides. The fractionation ranges from α = 1.030 to α = 1.048. The pattern is characteristic for a system essentially open to sulfate, and isotope analyses of interstitial sulfates are corroborative. A population of sulfate-reducing bacteria of the order of 10 9 organisms per cc of interstitial water is indicated. Seasonal variation of the isotope distribution reflects a transient sulfide composition and a bacterial population in which the fractionation effect is indirectly controlled by temperature. The data presented for this modern shallow water environment are at variance with an earlier assessment of isotopic distributions in ancient sulfides which linked shallow water environments with limited fractionation (α =< 1.025) in a closed system. (author)

  10. Sulfur isotope study of a modern intertidal environment, and the interpretation of ancient sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, L.A. (Baas Becking Geobiological Lab., Canberra City (Australia))

    1982-05-01

    Extensive sulfur isotope distribution data for sulfides precipitated in an intertidal environment show no distinctive features when compared with isotope values for other marine, sedimentary sulfides. The fractionation ranges from ..cap alpha.. = 1.030 to ..cap alpha.. = 1.048. The pattern is characteristic for a system essentially open to sulfate, and isotope analyses of interstitial sulfates are corroborative. A population of sulfate-reducing bacteria of the order of 10/sup 9/ organisms per cc of interstitial water is indicated. Seasonal variation of the isotope distribution reflects a transient sulfide composition and a bacterial population in which the fractionation effect is indirectly controlled by temperature. The data presented for this modern shallow water environment are at variance with an earlier assessment of isotopic distributions in ancient sulfides which linked shallow water environments with limited fractionation (..cap alpha.. =< 1.025) in a closed system.

  11. Reconnaissance of intertidal and subtidal zones of Back Island, Behm Canal, Southeast Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Strand, J.A.; Young, J.S.

    1986-09-01

    A diver reconnaissance of the intertidal and subtidal zones of Back Island, Southeast Alaska, was performed May 20-22, 1986. The specific objectives were to catalog potentially vulnerable shellfish, other invertebrates, and plant resources, and to identify potential herring spawning sites. This effort was designed to supplement the existing ecological data base for Back Island that would be used during the National Environmental Policy Act (NEPA) documentation process. A NEPA document will be prepared that describes the site environment and assesses impacts from the proposed construction and operation of the Southeast Alaska Acoustic Measurement Facility (SEAFAC). Nine diver transects were established around Back Island. Particular attention was devoted to proposed locations for the pier and float facilities and range-operations and shore-power cable run-ups.

  12. Macroscale patterns in body size of intertidal crustaceans provide insights on climate change effects

    Science.gov (United States)

    Dugan, Jenifer E.; Hubbard, David M.; Contreras, Heraldo; Duarte, Cristian; Acuña, Emilio; Schoeman, David S.

    2017-01-01

    Predicting responses of coastal ecosystems to altered sea surface temperatures (SST) associated with global climate change, requires knowledge of demographic responses of individual species. Body size is an excellent metric because it scales strongly with growth and fecundity for many ectotherms. These attributes can underpin demographic as well as community and ecosystem level processes, providing valuable insights for responses of vulnerable coastal ecosystems to changing climate. We investigated contemporary macroscale patterns in body size among widely distributed crustaceans that comprise the majority of intertidal abundance and biomass of sandy beach ecosystems of the eastern Pacific coasts of Chile and California, USA. We focused on ecologically important species representing different tidal zones, trophic guilds and developmental modes, including a high-shore macroalga-consuming talitrid amphipod (Orchestoidea tuberculata), two mid-shore scavenging cirolanid isopods (Excirolana braziliensis and E. hirsuticauda), and a low-shore suspension-feeding hippid crab (Emerita analoga) with an amphitropical distribution. Significant latitudinal patterns in body sizes were observed for all species in Chile (21° - 42°S), with similar but steeper patterns in Emerita analoga, in California (32°- 41°N). Sea surface temperature was a strong predictor of body size (-4% to -35% °C-1) in all species. Beach characteristics were subsidiary predictors of body size. Alterations in ocean temperatures of even a few degrees associated with global climate change are likely to affect body sizes of important intertidal ectotherms, with consequences for population demography, life history, community structure, trophic interactions, food-webs, and indirect effects such as ecosystem function. The consistency of results for body size and temperature across species with different life histories, feeding modes, ecological roles, and microhabitats inhabiting a single widespread coastal

  13. Impact of intertidal oyster trestle cultivation on the Ecological Status of benthic habitats.

    Science.gov (United States)

    Forde, James; O'Beirn, Francis X; O'Carroll, Jack Pj; Patterson, Adrian; Kennedy, Robert

    2015-06-15

    A considerable number of Ireland's shellfish production areas co-occur with or are adjacent to Natura 2000 sites which are protected under European legislation. To investigate the general interaction between trestle oyster cultivation and the surrounding intertidal environment, six sites were selected within designated Natura 2000 sites. At each trestle site three Treatment areas were sampled. One Treatment area corresponded to potential impacts associated with cultivation activities occurring at trestle structures (designated the Trestle Treatment) while one Treatment area corresponded to potential impacts due to cultivation activities occurring along access routes (the Access Treatment). An area not subject to any known anthropogenic activity was used as a control (the Control Treatment). Potential impacts associated with Trestle Treatment areas included changes in sediment total organic matter (TOM) levels underneath trestles due to the bio-deposition of faecal/pseudofaecal material while the predominant impact associated with Access Treatment areas was compaction of sediments due to heavy vehicle traffic. In this study, macrobenthic communities at the sites were highly variable and exhibited low levels of diversity which prevented the detection of general effects of cultivation activity on community structure, diversity and secondary production. To overcome this variability, the Infaunal Quality Index (IQI) was used to assess impacts on Ecological Status (ES) of benthic communities (sensu Water Framework Directive). Relative to Control and Trestle Treatment areas, activities occurring at Access Treatment areas had a significant negative impact on ES. This study highlights the potential of the IQI for the management of aquaculture activity and provides validation for the use of the IQI in Irish intertidal environments. This study also highlights the IQI as a potential tool for assessing the conservation status of designated habitats in Natura 2000 sites

  14. Indices, multispecies and synthesis descriptors in benthic assessments: Intertidal organic enrichment from oyster farming

    Science.gov (United States)

    Quintino, Victor; Azevedo, Ana; Magalhães, Luísa; Sampaio, Leandro; Freitas, Rosa; Rodrigues, Ana Maria; Elliott, Michael

    2012-09-01

    Intertidal off-bottom oyster culture is shown to cause organic enrichment of the shore and although there are two stressors of interest (the presence of a structure, the trestles, and also the sediment and organic waste from the oysters), these can be separated and their relative impacts determined using an appropriate nested experimental design and data treatments. Although no artificial food sources are involved, the oysters feeding activity and intensity of culture enhances biodeposition and significantly increases the sediment fines content and total organic matter. This in general impoverished the benthic community in culture areas rather than a species succession with the installation of opportunists or a resulting increase in the abundance and biomass of benthic species; the findings can be a direct consequence of the intertidal situation which is less-amenable recruitment of species more common to the subtidal environment. Thus the most appropriate biological descriptors to diagnose the effects associated with the organic enrichment were the multispecies abundance data as well as the primary biological variables species richness and abundance. The effects were however spatially and statistically significantly confined to the area located directly underneath the culture bags compared to the corridors located between the trestles, which do not show such enrichment effects. Synthesis biotic indices were much less effective to diagnose the benthic alterations associated with this organic enrichment. These results show that special attention must be paid when using indices in areas where the organic enrichment induces an impoverishment of the benthic community but not necessarily a species replacement with the installation of opportunists.

  15. Comparative microanatomical structure of gills and skin of remainers and skippers from Gunung Kidul intertidal zone

    Science.gov (United States)

    Putri, Rizka Apriani; Sukiya

    2017-08-01

    One type of adaptation needed in fish that live in Intertidal Zone is morphological adaptation. When the tide is low, oxygen circulation in this area is limited, causing tidepools that occurred during this time hypoxic for species that live inside. This research aimed to study the microanatomical structure of respiratory organ of two group of fish that live in intertidal zone and to investigate whether skin of these species can be used as respiratory surface to overcome hypoxic condition. Two species of fish (Bathygobiusfuscus of remainers group and Blenniellabilitonensis of skippers, respectively), were caught and sacrificed, then gills and skin of them were harvested. The organs then undergone further processing for microanatomical preparation with paraffin method and Hematoxylin-Eosin staining. Microanatomical structure of gills and skin analyzed descriptively. Gills were observed to study whether additional structure is presence and modification (in structure of epithelial cells and/or the length of secondary lamelae) is occurred as part of morphological change to absorb more oxygen during low tide. In skin, the thickness of epidermal layers were measured and the number of blood capillaries were counted to investigate whether it can also be used as additional respiratory surface. Quantitative data of skin and gills were statistically analyzed using Student's T-test. Results showed that there were no differences in gills structure between remainers and skippers. Additional structure in gills were absent in both species. However, quantitative measurements in skin showed that skippers have less layers of epidermal cells and high number of blood capillaries compared to remainers' skin. This results indicated that skippers were able to use their skin as additional respiratory surface outside gills.

  16. Sellafield waste radionuclides in Irish sea intertidal and salt marsh sediments.

    Science.gov (United States)

    Mackenzie, A B; Scott, R D

    1993-09-01

    Low level liquid radioactive waste discharges from the Sellafield nuclear fuel reprocessing plant in north west England had generated environmental inventories of about 3 × 10(16) Bq of(137)Cs, 6.8 × 10(14) Bq of(239,240)Pu and 8.9 × 10(14) Bq of(241)Am by 1990. Most of the(239,240)Pu and(241)Am and about 10% of the(137)Cs has been retained in a deposit of fine marine sediment close to the discharge point. The quantities of radionuclides discharged annually from Sellafield decreased by two orders of magnitude from the mid-1970s to 1990 but estimated critical group internal and external exposure decreased by less than one order of magnitude over this period. This indicates that during the period of reduced discharges, radionuclides already in the environment from previous releases continued to contribute to the critical group exposure and highlights the need to understand processes controlling the environmental distribution of the radionuclides.Redistribution of the contaminated marine sediment is potentially of major significance in this context, in particular if it results in transport of radionuclides to intertidal areas, where contact with the human population is relatively likely.A review is presented of published work relating to Sellafield waste radionuclides in Irish Sea sediments. Data on temporal and spatial trends in radionuclide concentrations and activity ratios are collated from a number of sources to show that the dominant mechanism of radionuclide supply to intertidal areas is by redistribution of the contaminated marine sediment. The implications of this mechanism of supply for trends in critical group radiation exposure are considered.

  17. Growth patterns of an intertidal gastropod as revealed by oxygen isotope analysis

    Science.gov (United States)

    Bean, J. R.; Hill, T. M.; Guerra, C.

    2007-12-01

    The size and morphology of mollusk shells are affected by environmental conditions. As a result, it is difficult to assess growth rate, population age structure, shell morphologies associated with ontogenetic stages, and to compare life history patterns across various environments. Oxygen isotope analysis is a useful tool for estimating minimum ages and growth rates of calcium carbonate secreting organisms. Calcite shell material from members of two northern California populations of the intertidal muricid gastropod Acanthinucella spirata was sampled for isotopic analysis. Individual shells were sampled from apex to margin, thus providing a sequential record of juvenile and adult growth. A. spirata were collected from a sheltered habitat in Tomales Bay and from an exposed reef in Bolinas. Abiotic factors, such as temperature, wave exposure, and substrate consistency, and biotic composition differ significantly between these sites, possibly resulting in local adaptations and variation in life history and growth patterns. Shell morphology of A. spirata changes with age as internal shell margin thickenings of denticle rows associated with external growth bands are irregularly accreted. It is not known when, either seasonally and/or ontogentically, these thickenings and bands form or whether inter or intra-populational variation exists. Preliminary results demonstrate the seasonal oxygen isotopic variability present at the two coastal sites, indicating 5-6 degC changes from winter to summertime temperatures; these data are consistent with local intertidal temperature records. Analysis of the seasonal patterns indicate that: 1) differences in growth rate and seasonal growth patterns at different ontogenetic stages within populations, and 2) differences in growth patterns and possibly age structure between the two A. spirata populations. These findings indicate that isotopic analyses, in addition to field observations and morphological measurements, are necessary to

  18. Reproductive cycles in tropical intertidal gastropods are timed around tidal amplitude cycles.

    Science.gov (United States)

    Collin, Rachel; Kerr, Kecia; Contolini, Gina; Ochoa, Isis

    2017-08-01

    Reproduction in iteroparous marine organisms is often timed with abiotic cycles and may follow lunar, tidal amplitude, or daily cycles. Among intertidal marine invertebrates, decapods are well known to time larval release to coincide with large amplitude nighttime tides, which minimizes the risk of predation. Such bimonthly cycles have been reported for few other intertidal invertebrates. We documented the reproduction of 6 gastropod species from Panama to determine whether they demonstrate reproductive cycles, whether these cycles follow a 2-week cycle, and whether cycles are timed so that larval release occurs during large amplitude tides. Two of the species ( Crepidula cf. marginalis and Nerita scabricosta ) showed nonuniform reproduction, but without clear peaks in timing relative to tidal or lunar cycles. The other 4 species show clear peaks in reproduction occurring every 2 weeks. In 3 of these species ( Cerithideopsis carlifornica var. valida, Littoraria variegata , and Natica chemnitzi ), hatching occurred within 4 days of the maximum amplitude tides. Siphonaria palmata exhibit strong cycles, but reproduction occurred during the neap tides. Strong differences in the intensity of reproduction of Cerithideopsis carlifornica , and in particular, Littoraria variegata , between the larger and smaller spring tides of a lunar month indicate that these species time reproduction with the tidal amplitude cycle rather than the lunar cycle. For those species that reproduce during both the wet and dry seasons, we found that reproductive timing did not differ between seasons despite strong differences in temperature and precipitation. Overall, we found that most (4/6) species have strong reproductive cycles synchronized with the tidal amplitude cycle and that seasonal differences in abiotic factors do not alter these cycles.

  19. Dynamics of sediment carbon stocks across intertidal wetland habitats of Moreton Bay, Australia.

    Science.gov (United States)

    Hayes, Matthew A; Jesse, Amber; Hawke, Bruce; Baldock, Jeff; Tabet, Basam; Lockington, David; Lovelock, Catherine E

    2017-10-01

    Coastal wetlands are known for high carbon storage within their sediments, but our understanding of the variation in carbon storage among intertidal habitats, particularly over geomorphological settings and along elevation gradients, is limited. Here, we collected 352 cores from 18 sites across Moreton Bay, Australia. We assessed variation in sediment organic carbon (OC) stocks among different geomorphological settings (wetlands within riverine settings along with those with reduced riverine influence located on tide-dominated sand islands), across elevation gradients, with distance from shore and among habitat and vegetation types. We used mid-infrared (MIR) spectroscopy combined with analytical data and partial least squares regression to quantify the carbon content of ~2500 sediment samples and provide fine-scale spatial coverage of sediment OC stocks to 150 cm depth. We found sites in river deltas had larger OC stocks (175-504 Mg/ha) than those in nonriverine settings (44-271 Mg/ha). Variation in OC stocks among nonriverine sites was high in comparison with riverine and mixed geomorphic settings, with sites closer to riverine outflow from the east and south of Moreton Bay having higher stocks than those located on the sand islands in the northwest of the bay. Sediment OC stocks increased with elevation within nonriverine settings, but not in riverine geomorphic settings. Sediment OC stocks did not differ between mangrove and saltmarsh habitats. OC stocks did, however, differ between dominant species across the research area and within geomorphic settings. At the landscape scale, the coastal wetlands of the South East Queensland catchments (17,792 ha) are comprised of approximately 4,100,000-5,200,000 Mg of sediment OC. Comparatively high variation in OC storage between riverine and nonriverine geomorphic settings indicates that the availability of mineral sediments and terrestrial derived OC may exert a strong influence over OC storage potential across

  20. Invisible trophic links? Quantifying the importance of non-standard food sources for key intertidal avian predators in the Eastern Atlantic

    NARCIS (Netherlands)

    Lourenço, P.M.; Catry, T.; Lopes, R.J.; Piersma, T.; Granadeiro, J.P.

    2017-01-01

    Coastal wetlands are heterogeneous systems with multiple inputs and complex interactionswithin local food webs. Interpreting such complexity is limited by incomplete knowledgeof trophic interactions among organisms. Although widely recognized as secondary consumersand predators of intertidal

  1. The intertidal community in West Greenland: Large-scale patterns and small-scale variation on ecosystem dynamics along a climate gradient

    DEFF Research Database (Denmark)

    Thyrring, Jakob; Blicher, Martin; Sejr, Mikael Kristian

    are largely unknown. The West Greenland coast is north - south orientated. This provides an ideal setting to study the impact of climate change on marine species population dynamics and distribution. We investigated the latitudinal changes in the rocky intertidal community along 18° latitudes (59-77°N......) in West Greenland. Using cleared quadrats we quantified patterns in abundance, biomass and species richness in the intertidal zone. We use this data to disentangle patterns in Arctic intertidal communities at different scales. We describe the effects of different environmental drivers and species...... interactions on distribution and dynamics of intertidal species. Our results indicate that changes in distribution and abundance of foundation species can have large effects on the ecosystem. We also show that the importance of small-scale variation may be of same magnitude as large- scale variation. Only...

  2. Intensities of drilling predation of molluscan assemblages in intertidal and subtidal soft substrates in the Persian (Arabian) Gulf

    Science.gov (United States)

    Handler, Sabine M.; Albano, Paolo G.; Bentlage, Rudolf; Drummond, Hannah; García-Ramos, Diego A.; Zuschin, Martin

    2016-04-01

    Intensities of drilling predation of molluscan assemblages in intertidal and subtidal soft substrates in the Persian (Arabian) Gulf Sabine Maria Handler1, Paolo G. Albano1, Rudolf Bentlage2, Hannah Drummond2, D.A. García-Ramos1, Martin Zuschin1 1 Department of Paleontology, University of Vienna, Austria 2 St. Lawrence University, Canton, New York 13617, USA Trace fossils left by predators in the skeleton of their prey are arguably one of the most powerful sources of direct data on predator-prey interactions available in the fossil record. Drill holes, especially those attributed to naticid and muricid gastropods, are unambiguous marks of predation and allow discriminating between successful and unsuccessful predation attempts (complete and incomplete holes, respectively). Latitude and water depth influence drilling frequency. We inspected death assemblages of an intertidal flat and of two subtidal (water depth between 6 and 20 m) sandy sites in the Persian (Arabian) Gulf, off the coast of the United Arab Emirates, to determine the patterns of predation on shelled molluscs along the depth gradient. The study is based on ~7,000 and ~60,000 shells from the intertidal and subtidal, respectively. Drilling Frequency (DF, the number of drilled individuals), Incomplete Drilling Frequency (IDF, number of incomplete drill holes), and Prey Effectiveness (ratio between the number of incomplete drill holes and the total number of drilling attempts) were used as metrics of drilling intensity. We observed major differences between the intertidal and subtidal study areas. Drilling frequencies were generally remarkably low and intertidal flats showed a much lower drilling frequency than the subtidal (1.4% and 6.7%, respectively). In the subtidal, we observed significant differences of drilling intensity among bivalve species and between the two sites. However, predation metrics did not correlate with environmental factors such as substrate type and depth, nor with species life

  3. Pressure control valve using proportional electro-magnetic solenoid actuator

    International Nuclear Information System (INIS)

    Yun, So Nam; Ham, Young Bog; Park, Pyoung Won

    2006-01-01

    This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed

  4. Development of extruded resistive plastic tubes for proportional chamber cathodes

    International Nuclear Information System (INIS)

    Kondo, K.

    1982-01-01

    Carbon mixed plastic tubes with resistivity of 10 3 approx. 10 4 Ωcm have been molded with an extrusion method and used for the d.c. cathode of a proportional counter and a multi-wire proportional chamber. The signal by gas multiplication was picked up from a strip r.f. cathode set outside the tube. The characteristics of the counter in the proportional and limited streamer modes have been studied

  5. Impacts of Near-Future Ocean Acidification and Warming on the Shell Mechanical and Geochemical Properties of Gastropods from Intertidal to Subtidal Zones.

    Science.gov (United States)

    Leung, Jonathan Y S; Connell, Sean D; Nagelkerken, Ivan; Russell, Bayden D

    2017-11-07

    Many marine organisms produce calcareous shells as the key structure for defense, but the functionality of shells may be compromised by ocean acidification and warming. Nevertheless, calcifying organisms may adaptively modify their shell properties in response to these impacts. Here, we examined how reduced pH and elevated temperature affect shell mechanical and geochemical properties of common grazing gastropods from intertidal to subtidal zones. Given the greater environmental fluctuations in the intertidal zone, we hypothesized that intertidal gastropods would exhibit more plastic responses in shell properties than subtidal gastropods. Overall, three out of five subtidal gastropods produced softer shells at elevated temperature, while intertidal gastropods maintained their shell hardness at both elevated pCO 2 (i.e., reduced pH) and temperature. Regardless of pH and temperature, degree of crystallization was maintained (except one subtidal gastropod) and carbonate polymorph remained unchanged in all tested species. One intertidal gastropod produced less soluble shells (e.g., higher calcite/aragonite) in response to reduced pH. In contrast, subtidal gastropods produced only aragonite which has higher solubility than calcite. Overall, subtidal gastropods are expected to be more susceptible than intertidal gastropods to shell dissolution and physical damage under future seawater conditions. The increased vulnerability to shell dissolution and predation could have serious repercussions for their survival and ecological contributions in the future subtidal environment.

  6. Spatial and temporal distribution of nitrite-dependent anaerobic methane-oxidizing bacteria in an intertidal zone of the East China Sea.

    Science.gov (United States)

    Wang, Jiaqi; Shen, Lidong; He, Zhanfei; Hu, Jiajie; Cai, Zhaoyang; Zheng, Ping; Hu, Baolan

    2017-11-01

    Nitrite-dependent anaerobic methane oxidation (N-DAMO), which couples anaerobic methane oxidation and nitrite reduction, is a recently discovered bioprocess coupling microbial nitrogen and carbon cycles. The discovery of this microbial process challenges the traditional knowledge of global methane sinks and nitrogen losses. In this study, the abundance and activity of N-DAMO bacteria were investigated and their contributions to methane sink and nitrogen loss were estimated in different seasons and different partitions of an intertidal zone of the East China Sea. The results showed that N-DAMO bacteria were extensively and continuously present in the intertidal zone, with the number of cells ranging from 5.5 × 10 4 to 2.8 × 10 5 copy g -1 soil and the potential activity ranging from 0.52 to 5.7 nmol CO 2  g -1 soil day -1 , contributing 5.0-36.6% of nitrite- and sulfate-dependent anaerobic methane oxidation in the intertidal zone. The N-DAMO activity and its contribution to the methane consumption were highest in the spring and in the low intertidal zone. These findings showed that the N-DAMO process is an important methane and nitrogen sink in the intertidal zone and varies with the seasons and the partitions of the intertidal zone.

  7. Multiwire proportional chamber for Moessbauer spectroscopy: development and results

    International Nuclear Information System (INIS)

    Costa, M.S. da.

    1985-12-01

    A new Multiwere proportional Chamber designed for Moessbauer Spectroscopy is presented. This detector allows transmission backscattering experiments using either photons or electrons. The Moessbauer data acquisition system, partially developed for this work is described. A simple method for determining the frontier between true proportional and semi-proportional regions of operation in gaseous detectors is proposed. The study of the tertiary gas mixture He-Ar-CH 4 leads to a straight forward way of energy calibration of the electron spectra. Moessbauer spectra using Fe-57 source are presented. In particular those obtained with backsattered electrons show the feasibility of depth selective analysis with gaseous proportional counters. (author) [pt

  8. Predicting Pollicipes pollicipes (Crustacea: Cirripedia abundance on intertidal rocky shores of SW Portugal: a multi-scale approach based on a simple fetch-based wave exposure index

    Directory of Open Access Journals (Sweden)

    David Jacinto

    2016-06-01

    Full Text Available Understanding and predicting patterns of distribution and abundance of marine resources is important for conservation and management purposes in small-scale artisanal fisheries and industrial fisheries worldwide. The goose barnacle (Pollicipes pollicipes is an important shellfish resource and its distribution is closely related to wave exposure at different spatial scales. We modelled the abundance (percent coverage of P. pollicipes as a function of a simple wave exposure index based on fetch estimates from digitized coastlines at different spatial scales. The model accounted for 47.5% of the explained deviance and indicated that barnacle abundance increases non-linearly with wave exposure at both the smallest (metres and largest (kilometres spatial scales considered in this study. Distribution maps were predicted for the study region in SW Portugal. Our study suggests that the relationship between fetch-based exposure indices and P. pollicipes percent cover may be used as a simple tool for providing stakeholders with information on barnacle distribution patterns. This information may improve assessment of harvesting grounds and the dimension of exploitable areas, aiding management plans and supporting decision making on conservation, harvesting pressure and surveillance strategies for this highly appreciated and socio-economically important marine resource.

  9. Impact of prolonged storm activity on the Ecological Status of intertidal benthic habitats within oyster (Crassostrea gigas) trestle cultivation sites.

    Science.gov (United States)

    O'Carroll, Jack P J; Quinn, Christina; Forde, James; Patterson, Adrian; O'Beirn, Francis X; Kennedy, Robert

    2016-09-15

    The Ecological Status (ES; sensu the Water Framework Directive) of intertidal benthic communities within six oyster trestle cultivation sites was found to be negatively impacted along the access routes to trestles in a 2013 study. All cultivation sites occur within Natura 2000 sites. The current study revisited four of the 2013 cultivation sites in February 2014 one month after the storm activity of winter 2013/14 to test if the compaction effect along access routes persisted after the storms. Three levels of the fixed factor treatment were sampled; immediately below the trestles, along the access route and 300m away from any anthropogenic activity. The compaction effect at the Access treatment persisted in spite of the major storm activity. The current study showed the IQI to be effective for assessing the impacts of aquaculture and highlights the IQI as a tool for monitoring Conservation Status of intertidal communities under the Habitats Directive. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Bacterial community structure in response to environmental impacts in the intertidal sediments along the Yangtze Estuary, China.

    Science.gov (United States)

    Guo, Xing-Pan; Lu, Da-Pei; Niu, Zuo-Shun; Feng, Jing-Nan; Chen, Yu-Ru; Tou, Fei-Yun; Liu, Min; Yang, Yi

    2018-01-01

    This study was designed to investigate the characteristics of bacterial communities in intertidal sediments along the Yangtze Estuary and their responses to environmental factors. The results showed that bacterial abundance was significantly correlated with salinity, SO 4 2- and total organic carbon, while bacterial diversity was significantly correlated with SO 4 2- and total nitrogen. At different taxonomic levels, both the dominant taxa and their abundances varied among the eight samples, with Proteobacteria being the most dominant phylum in general. Cluster analysis revealed that the bacterial community structure was influenced by river runoff and sewerage discharge. Moreover, SO 4 2- , salinity and total phosphorus were the vital environmental factors that influenced the bacterial community structure. Quantitative PCR and sequencing of sulphate-reducing bacteria indicated that the sulphate reduction process occurs frequently in intertidal sediments. These findings are important to understand the microbial ecology and biogeochemical cycles in estuarine environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Middle Triassic chirotherid trackways on earthquake influenced intertidal limulid reproduction flats of the European Germanic Basin coasts

    Science.gov (United States)

    Diedrich, Cajus G.

    2012-09-01

    Chirotherid footprints of Synaptichnium, Chirotherium and Isochirotherium appeared during the late Early (Aegean) to early Late (Carnian) Triassic in central Europe. These taxa are partly revised herein, using both perfect and variably preserved tracks, and very long trackways from an upper Pelsonian intertidal-flat megatracksite of the Germanic Basin coast Pelsonian (Karlstadt Formation). The global Middle Triassic distribution of those footprints suggests seasonal migrations across Pangaea of possible archosauriform reptile trackmakers, such as Euparkeria, Ticinosuchus, Arizonasaurus and Batrachotomus, caused by horseshoe-crab mass migrations into tidal-flat beach reproductive zones in the Germanic Basin. Such seasonal migrations may even suggest a Pangaea-wide food-chain reaction, possibly including the mobilization of fish, marine and terrestrial reptiles, and of which situation the Germanic Basin intertidal-flats is a globally unique example.

  12. Invasion of a rocky intertidal shore by the tunicate Pyura praeputialis in the Bay of Antofagasta, Chile.

    Science.gov (United States)

    Castilla, Juan Carlos; Guiñez, Ricardo; Caro, Andrés U; Ortiz, Verónica

    2004-06-08

    Invasion by marine nonindigenous species (NIS) is a spread phenomenon. The tunicate Pyura praeputialis shows pronounced disjoint geographical distribution: along thousands of kilometers in wave-swept headlands on the southeastern coast of Australia, from where it appears to have originated, and exclusively along 60-70 km inside the Bay of Antofagasta, Chile. mtDNA sequences suggested that the species invaded this rocky shore recently. We used field manipulations and juvenile P. praeputialis transplant techniques to test hypotheses regarding the capacity of the tunicate to survive and grow at different sites and tidal heights inside and outside Antofagasta, and its competitive performance for primary space (inside the Bay) against the native mussel Perumytilus purpuratus. We conclude that survival and growth of P. praeputialis showed no significant differences among sites inside and outside the Bay, and suggest that the restrictive distribution of the species in Chile is caused by a specific oceanographic retention mechanism and/or its brief larval dispersal. We demonstrated that, inside the Bay, P. praeputialis outcompetes Perumytilus from the Mid-Low intertidal, constraining Perumytilus to the Upper Mid-Intertidal, modifying the local pattern of intertidal zonation. We show that predation on P. praeputialis juveniles by starfish and snails constitutes a regulatory mechanism for the setting of its low intertidal limit. Major ecological impacts caused by NIS invasions to rocky shores by aggressive primary space users may result in negative aspects, but also may contribute to biodiversity enhancement. We call attention to the need for increment manipulations and testing of ecological hypotheses regarding marine NIS.

  13. Substantial nitrous oxide emissions from intertidal sediments and groundwater in anthropogenically-impacted West Falmouth Harbor, Massachusetts

    Science.gov (United States)

    Moseman-Valtierra, Serena; Kroeger, Kevin D.; Crusius, John; Baldwin, Sandy; Green, Adrian; Brooks, Thomas W.; Pugh, E.

    2015-01-01

    Large N2O emissions were observed from intertidal sediments in a coastal estuary, West Falmouth Harbor, MA, USA. Average N2O emission rates from 41 chambers during summer 2008 were 10.7 mol N2O m(-2) h(-1)±4.43 μmol N2O m(-2) h(-1) (standard error). Emissions were highest from sediments within a known wastewater plume, where a maximum N2O emission rate was 155 μmol N2O m(-2) h(-1). Intertidal N2O fluxes were positively related to porewater ammonium concentrations at 10 and 25 cm depths. In groundwater from 7 shoreline wells, dissolved N2O ranged from 488% of saturation (56 nM N2O) to more than 13000% of saturation (1529 nM N2O) and was positively related to nitrate concentrations. Fresh and brackish porewater underlying 14 chambers was also supersaturated in N2O, ranging from 2980% to 13175% of saturation. These observations support a relationship between anthropogenic nutrient loading and N2O emissions in West Falmouth Harbor, with both groundwater sources and also local N2O production within nutrient-rich, intertidal sediments in the groundwater seepage face. N2O emissions from intertidal "hotspot" in this harbor, together with estimated surface water emissions, constituted 2.4% of the average overall rate of nitrogen export from the watershed to the estuary. This suggests that N2O emissions factors from coastal ecosystems may be underestimated. Since anthropogenic nutrient loading affects estuaries worldwide, quantification of N2O dynamics is warranted in other anthropogenically-impacted coastal ecosystems.

  14. Substantial nitrous oxide emissions from intertidal sediments and groundwater in anthropogenically-impacted West Falmouth Harbor, Massachusetts.

    Science.gov (United States)

    Moseman-Valtierra, Serena; Kroeger, Kevin D; Crusius, John; Baldwin, Sandra; Green, Adrian; Brooks, T Wallace; Pugh, Emily

    2015-01-01

    Large N2O emissions were observed from intertidal sediments in a coastal estuary, West Falmouth Harbor, MA, USA. Average N2O emission rates from 41 chambers during summer 2008 were 10.7 mol N2O m(-2) h(-1)±4.43 μmol N2O m(-2) h(-1) (standard error). Emissions were highest from sediments within a known wastewater plume, where a maximum N2O emission rate was 155 μmol N2O m(-2) h(-1). Intertidal N2O fluxes were positively related to porewater ammonium concentrations at 10 and 25 cm depths. In groundwater from 7 shoreline wells, dissolved N2O ranged from 488% of saturation (56 nM N2O) to more than 13000% of saturation (1529 nM N2O) and was positively related to nitrate concentrations. Fresh and brackish porewater underlying 14 chambers was also supersaturated in N2O, ranging from 2980% to 13175% of saturation. These observations support a relationship between anthropogenic nutrient loading and N2O emissions in West Falmouth Harbor, with both groundwater sources and also local N2O production within nutrient-rich, intertidal sediments in the groundwater seepage face. N2O emissions from intertidal "hotspot" in this harbor, together with estimated surface water emissions, constituted 2.4% of the average overall rate of nitrogen export from the watershed to the estuary. This suggests that N2O emissions factors from coastal ecosystems may be underestimated. Since anthropogenic nutrient loading affects estuaries worldwide, quantification of N2O dynamics is warranted in other anthropogenically-impacted coastal ecosystems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Succession in rocky intertidal benthic communities in areas with different pollution levels at Guanabara Bay (RJ-Brazil)

    OpenAIRE

    Breves-Ramos, André; Lavrado, Helena Passeri; Junqueira, Andrea de Oliveira Ribeiro; Silva, Sérgio Henrique Gonçalves da

    2005-01-01

    The aim of this study was to describe and compare the succession of intertidal benthic communities in two areas at Guanabara Bay, RJ, Brazil: Urca, an area submitted to moderated organic pollution and Catalão, an extremely polluted area. Three transects in each area were scraped one month before the beginning of this study in order to evaluate the recruitment (recruitment-treatments). Three other transects were monitored without manipulation (monitoring treatments). Species composition and re...

  16. X-ray proportional counter for the Viking Lander

    International Nuclear Information System (INIS)

    Glesius, F.L.; Kroon, J.C.; Castro, A.J.; Clark, B.C.

    1978-01-01

    A set of four sealed proportional counters with optimized energy response is employed in the X-ray fluorescence spectrometer units aboard the two Viking Landers. The instruments have provided quantitative elemental analyses of soil samples taken from the Martian surface. This paper discusses the design and development of these miniature proportional counters, and describes their performance on Mars

  17. Putative golden proportions as predictors of facial esthetics in adolescents.

    Science.gov (United States)

    Kiekens, Rosemie M A; Kuijpers-Jagtman, Anne Marie; van 't Hof, Martin A; van 't Hof, Bep E; Maltha, Jaap C

    2008-10-01

    In orthodontics, facial esthetics is assumed to be related to golden proportions apparent in the ideal human face. The aim of the study was to analyze the putative relationship between facial esthetics and golden proportions in white adolescents. Seventy-six adult laypeople evaluated sets of photographs of 64 adolescents on a visual analog scale (VAS) from 0 to 100. The facial esthetic value of each subject was calculated as a mean VAS score. Three observers recorded the position of 13 facial landmarks included in 19 putative golden proportions, based on the golden proportions as defined by Ricketts. The proportions and each proportion's deviation from the golden target (1.618) were calculated. This deviation was then related to the VAS scores. Only 4 of the 19 proportions had a significant negative correlation with the VAS scores, indicating that beautiful faces showed less deviation from the golden standard than less beautiful faces. Together, these variables explained only 16% of the variance. Few golden proportions have a significant relationship with facial esthetics in adolescents. The explained variance of these variables is too small to be of clinical importance.

  18. Putative golden proportions as predictors of facial esthetics in adolescents.

    NARCIS (Netherlands)

    Kiekens, R.M.A.; Kuijpers-Jagtman, A.M.; Hof, M.A. van 't; Hof, B.E. van 't; Maltha, J.C.

    2008-01-01

    INTRODUCTION: In orthodontics, facial esthetics is assumed to be related to golden proportions apparent in the ideal human face. The aim of the study was to analyze the putative relationship between facial esthetics and golden proportions in white adolescents. METHODS: Seventy-six adult laypeople

  19. The principle of proportionality and European contract law

    NARCIS (Netherlands)

    Cauffman, C.; Rutgers, J.; Sirena, P.

    2015-01-01

    The paper investigates the role of the principle of proportionality within contract law, in balancing the rights and obligations of the contracting parties. It illustrates that the principle of proportionality is one of the general principles which govern contractual relations, and as such it is an

  20. The Improved Estimation of Ratio of Two Population Proportions

    Science.gov (United States)

    Solanki, Ramkrishna S.; Singh, Housila P.

    2016-01-01

    In this article, first we obtained the correct mean square error expression of Gupta and Shabbir's linear weighted estimator of the ratio of two population proportions. Later we suggested the general class of ratio estimators of two population proportions. The usual ratio estimator, Wynn-type estimator, Singh, Singh, and Kaur difference-type…

  1. Attention Modulation by Proportion Congruency: The Asymmetrical List Shifting Effect

    Science.gov (United States)

    Abrahamse, Elger L.; Duthoo, Wout; Notebaert, Wim; Risko, Evan F.

    2013-01-01

    Proportion congruency effects represent hallmark phenomena in current theorizing about cognitive control. This is based on the notion that proportion congruency determines the relative levels of attention to relevant and irrelevant information in conflict tasks. However, little empirical evidence exists that uniquely supports such an attention…

  2. 16 CFR 240.9 - Proportionally equal terms.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Proportionally equal terms. 240.9 Section 240.9 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR ADVERTISING ALLOWANCES AND OTHER MERCHANDISING PAYMENTS AND SERVICES § 240.9 Proportionally equal terms. (a...

  3. Integrating a DNA barcoding project with an ecological survey: a case study on temperate intertidal polychaete communities in Qingdao, China

    Science.gov (United States)

    Zhou, Hong; Zhang, Zhinan; Chen, Haiyan; Sun, Renhua; Wang, Hui; Guo, Lei; Pan, Haijian

    2010-07-01

    In this study, we integrated a DNA barcoding project with an ecological survey on intertidal polychaete communities and investigated the utility of CO1 gene sequence as a DNA barcode for the classification of the intertidal polychaetes. Using 16S rDNA as a complementary marker and combining morphological and ecological characterization, some of dominant and common polychaete species from Chinese coasts were assessed for their taxonomic status. We obtained 22 haplotype gene sequences of 13 taxa, including 10 CO1 sequences and 12 16S rDNA sequences. Based on intra- and inter-specific distances, we built phylogenetic trees using the neighbor-joining method. Our study suggested that the mitochondrial CO1 gene was a valid DNA barcoding marker for species identification in polychaetes, but other genes, such as 16S rDNA, could be used as a complementary genetic marker. For more accurate species identification and effective testing of species hypothesis, DNA barcoding should be incorporated with morphological, ecological, biogeographical, and phylogenetic information. The application of DNA barcoding and molecular identification in the ecological survey on the intertidal polychaete communities demonstrated the feasibility of integrating DNA taxonomy and ecology.

  4. Community regulation: the relative importance of recruitment and predation intensity of an intertidal community dominant in a seascape context.

    Science.gov (United States)

    Rilov, Gil; Schiel, David R

    2011-01-01

    Predicting the strength and context-dependency of species interactions across multiple scales is a core area in ecology. This is especially challenging in the marine environment, where populations of most predators and prey are generally open, because of their pelagic larval phase, and recruitment of both is highly variable. In this study we use a comparative-experimental approach on small and large spatial scales to test the relationship between predation intensity and prey recruitment and their relative importance in shaping populations of a dominant rocky intertidal space occupier, mussels, in the context of seascape (availability of nearby subtidal reef habitat). Predation intensity on transplanted mussels was tested inside and outside cages and recruitment was measured with standard larval settlement collectors. We found that on intertidal rocky benches with contiguous subtidal reefs in New Zealand, mussel larval recruitment is usually low but predation on recruits by subtidal consumers (fish, crabs) is intense during high tide. On nearby intertidal rocky benches with adjacent sandy subtidal habitats, larval recruitment is usually greater but subtidal predators are typically rare and predation is weaker. Multiple regression analysis showed that predation intensity accounts for most of the variability in the abundance of adult mussels compared to recruitment. This seascape-dependent, predation-recruitment relationship could scale up to explain regional community variability. We argue that community ecology models should include seascape context-dependency and its effects on recruitment and species interactions for better predictions of coastal community dynamics and structure.

  5. Retrospective qualitative analysis of ecological networks under environmental perturbation: a copper-polluted intertidal community as a case study.

    Science.gov (United States)

    Ramos-Jiliberto, Rodrigo; Garay-Narváez, Leslie; Medina, Matías H

    2012-01-01

    The coast of Chañaral Bay in northern Chile has been affected by copper mine wastes for decades. This sustained perturbation has disrupted the intertidal community in several ways, but the mechanisms behind the observed shifts in local biodiversity remain poorly understood. Our main goal was to identify the species (lumped into trophic groups) belonging to the Chañaral intertidal community that, being directly affected by copper pollution, contributed primarily to the generation of the observed changes in community structure. These groups of species were called initiators. We applied a qualitative modelling approach based only on the sign and direction of effects among species, and present a formula for predicting changes in equilibrium abundances considering stress on multiple variables simultaneously. We then applied this technique retrospectively to identify the most likely set of initiators. Our analyses allowed identification of a unique set of four initiators in the studied intertidal system (a group of algae, sessile invertebrates, a group of herbivores and starfish), which were hypothesized to be the primary drivers of the observed changes in community structure. In addition, a hypothesis was derived about how the perturbation affected these initiators. The hypothesis is that pollution affected negatively the population growth rate of both algae and sessile invertebrates and suppressed the interaction between herbivores and starfish. Our analytic approach, focused on identifying initiators, constitutes an advance towards understanding the mechanisms underlying human-driven ecosystem disruption and permits identifying species that may serve as a focal point for community management and restoration.

  6. Recolonization of the intertidal and shallow subtidal community following the 2008 eruption of Alaska’s Kasatochi Volcano

    Science.gov (United States)

    Jewett, S.C.; Drew, Gary S.

    2014-01-01

    The intertidal and nearshore benthic communities of Kasatochi Island are described following a catastrophic volcanic eruption in 2008. Prior to the eruption, the island was surrounded by a dense bed of canopy-forming dragon kelp Eualaria fistulosa which supported a productive nearshore community. The eruption extended the coastline of the island approximately 400 m offshore to roughly the 20 m isobath. One year following the eruption a reconnaissance survey found the intertidal zone devoid of life. Subtidally, the canopy kelp, as well as limited understory algal species and associated benthic fauna on the hard substratum, were buried by debris from the eruption. The resulting substrate was comprised almost entirely of medium and coarse sands with a depauperate benthic community. Comparisons of habitat and biological communities with other nearby Aleutian Islands and the Icelandic submarine volcanic eruption of Surtsey confirm dramatic reductions in flora and fauna consistent with the initial stages of recovery from a large-scale disturbance event. Four and five years following the eruption brief visits revealed dramatic intertidal and subtidal recolonization of the flora and fauna in some areas. Signs of nesting and fledging of young pigeon guillemots Cepphus columba suggest that the recovery of the nearshore biota may have begun affecting higher trophic levels. Recolonization or lack thereof was tied to bathymetric changes from coastal and nearshore erosion over the study period.

  7. Community regulation: the relative importance of recruitment and predation intensity of an intertidal community dominant in a seascape context.

    Directory of Open Access Journals (Sweden)

    Gil Rilov

    Full Text Available Predicting the strength and context-dependency of species interactions across multiple scales is a core area in ecology. This is especially challenging in the marine environment, where populations of most predators and prey are generally open, because of their pelagic larval phase, and recruitment of both is highly variable. In this study we use a comparative-experimental approach on small and large spatial scales to test the relationship between predation intensity and prey recruitment and their relative importance in shaping populations of a dominant rocky intertidal space occupier, mussels, in the context of seascape (availability of nearby subtidal reef habitat. Predation intensity on transplanted mussels was tested inside and outside cages and recruitment was measured with standard larval settlement collectors. We found that on intertidal rocky benches with contiguous subtidal reefs in New Zealand, mussel larval recruitment is usually low but predation on recruits by subtidal consumers (fish, crabs is intense during high tide. On nearby intertidal rocky benches with adjacent sandy subtidal habitats, larval recruitment is usually greater but subtidal predators are typically rare and predation is weaker. Multiple regression analysis showed that predation intensity accounts for most of the variability in the abundance of adult mussels compared to recruitment. This seascape-dependent, predation-recruitment relationship could scale up to explain regional community variability. We argue that community ecology models should include seascape context-dependency and its effects on recruitment and species interactions for better predictions of coastal community dynamics and structure.

  8. Intrinsic rates of petroleum hydrocarbon biodegradation in Gulf of Mexico intertidal sandy sediments and its enhancement by organic substrates

    International Nuclear Information System (INIS)

    Mortazavi, Behzad; Horel, Agota; Beazley, Melanie J.; Sobecky, Patricia A.

    2013-01-01

    The rates of crude oil degradation by the extant microorganisms in intertidal sediments from a northern Gulf of Mexico beach were determined. The enhancement in crude oil degradation by amending the microbial communities with marine organic matter was also examined. Replicate mesocosm treatments consisted of: (i) controls (intertidal sand), (ii) sand contaminated with crude oil, (iii) sand plus organic matter, and (iv) sand plus crude oil and organic matter. Carbon dioxide (CO 2 ) production was measured daily for 42 days and the carbon isotopic ratio of CO 2 (δ 13 CO 2 ) was used to determine the fraction of CO 2 derived from microbial respiration of crude oil. Bacterial 16S rRNA clone library analyses indicated members of Actinobacteria, Bacteroidetes, and Chloroflexi occurred exclusively in control sediments whereas Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Firmicutes occurred in both control and oil contaminated sediments. Members of the hydrocarbon-degrading genera Hydrocarboniphaga, Pseudomonas, and Pseudoxanthomonas were found primarily in oil contaminated treatments. Hydrocarbon mineralization was 76% higher in the crude oil amended with organic matter treatment compared to the rate in the crude oil only treatment indicating that biodegradation of crude oil in the intertidal zone by an extant microbial community is enhanced by input of organic matter

  9. Intrinsic rates of petroleum hydrocarbon biodegradation in Gulf of Mexico intertidal sandy sediments and its enhancement by organic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mortazavi, Behzad [University of Alabama, Department of Biological Sciences, Box 870344, University of Alabama, Tuscaloosa, AL 35487 (United States); Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL, 36528 (United States); Horel, Agota [University of Alabama, Department of Biological Sciences, Box 870344, University of Alabama, Tuscaloosa, AL 35487 (United States); Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL, 36528 (United States); Beazley, Melanie J.; Sobecky, Patricia A. [University of Alabama, Department of Biological Sciences, Box 870344, University of Alabama, Tuscaloosa, AL 35487 (United States)

    2013-01-15

    The rates of crude oil degradation by the extant microorganisms in intertidal sediments from a northern Gulf of Mexico beach were determined. The enhancement in crude oil degradation by amending the microbial communities with marine organic matter was also examined. Replicate mesocosm treatments consisted of: (i) controls (intertidal sand), (ii) sand contaminated with crude oil, (iii) sand plus organic matter, and (iv) sand plus crude oil and organic matter. Carbon dioxide (CO{sub 2}) production was measured daily for 42 days and the carbon isotopic ratio of CO{sub 2} (δ{sup 13}CO{sub 2}) was used to determine the fraction of CO{sub 2} derived from microbial respiration of crude oil. Bacterial 16S rRNA clone library analyses indicated members of Actinobacteria, Bacteroidetes, and Chloroflexi occurred exclusively in control sediments whereas Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Firmicutes occurred in both control and oil contaminated sediments. Members of the hydrocarbon-degrading genera Hydrocarboniphaga, Pseudomonas, and Pseudoxanthomonas were found primarily in oil contaminated treatments. Hydrocarbon mineralization was 76% higher in the crude oil amended with organic matter treatment compared to the rate in the crude oil only treatment indicating that biodegradation of crude oil in the intertidal zone by an extant microbial community is enhanced by input of organic matter.

  10. Soil organic matter degradation and enzymatic profiles of intertidal and subaqueous soils

    Science.gov (United States)

    Ferronato, Chiara; Marinari, Sara; Bello, Diana; Vianello, Gilmo; Trasar-Cepeda, Carmen; Vittori Antisari, Livia

    2017-04-01

    The interest on intertidal and subaqueous soils has recently arisen because of the climate changes forecasts. The preservation of these habitats represents an important challenge for the future of humanity, because these systems represent an important global C sink since soil organic matter (SOM) on intertidal and subaqueous soils undergoes very slow degradation rates due to oxygen limitation. Publications on SOM cycle in saltmarshes are very scarce because of the difficulties involved on those studies i.e. the interaction of many abiotic and biotic factors (e.g., redox changes, water and bio-turbation processes, etc) and stressors (e.g., salinity and anoxia). However, saltmarshes constitute an unique natural system to observe the influence of anoxic conditions on SOM degradation, because the tide fluctuations on the soil surface allow the formation of provisionally or permanently submerged soils. With the aim to investigate the quality of SOM in subaqueous soils, triplicates of subaqueous soils (SASs), intertidal soils (ITSs) and terrestrial soils (TESs) were collected in the saltmarshes of the Baiona Lagoon (Northern Italy) and classified according to their pedogenetic horizons. The SOM quality on each soil horizon was investigated by quantifying SOM, total and water-soluble organic carbon (TOC, WSC) and microbial biomass carbon (MBC). Given the contribution of soil enzymes to the degradation of SOM, some enzymatic assays were also performed. Thereafter, soil classification and humus morpho-functional classification were used to join together similar soil profiles to facilitate the description and discussion of results. Soils were ranked as Aquent or Wassent Entisols, with an A/AC/C pedosequence. SOM, TOC and MBC were statistically higher in A than in AC and C horizons. Among the A horizons, ITSs were those showing the highest values for these parameters (11% TOC, 1.6 mg kg-1 MBC, 0.9 mg kg-1 WSC). These results, combined with the morpho-functional classification

  11. The role of gaping behaviour in habitat partitioning between coexisting intertidal mussels

    Directory of Open Access Journals (Sweden)

    Stephens Linda

    2010-07-01

    Full Text Available Abstract Background Environmental heterogeneity plays a major role in invasion and coexistence dynamics. Habitat segregation between introduced species and their native competitors is usually described in terms of different physiological and behavioural abilities. However little attention has been paid to the effects of behaviour in habitat partitioning among invertebrates, partially because their behavioural repertoires, especially marine benthic taxa, are extremely limited. This study investigates the effect of gaping behaviour on habitat segregation of the two dominant mussel species living in South Africa, the invasive Mytilus galloprovincialis and the indigenous Perna perna. These two species show partial habitat segregation on the south coast of South Africa, the lower and upper areas of the mussel zone are dominated by P. perna and M. galloprovincialis respectively, with overlap in the middle zone. During emergence, intertidal mussels will either keep the valves closed, minimizing water loss and undergoing anaerobic metabolism, or will periodically open the valves maintaining a more efficient aerobic metabolism but increasing the risk of desiccation. Results Our results show that, when air exposed, the two species adopt clearly different behaviours. M. galloprovincialis keeps the shell valves closed, while P. perna periodically gapes. Gaping behaviour increased water loss in the indigenous species, and consequently the risk of desiccation. The indigenous species expressed significantly higher levels of stress protein (Hsp70 than M. galloprovincialis under field conditions and suffered significantly higher mortality rates when exposed to air in the laboratory. In general, no intra-specific differences were observed in relation to intertidal height. The absence of gaping minimises water loss but exposes the invasive species to other stresses, probably related to anoxic respiration. Conclusions Gaping affects tolerance to desiccation, thus

  12. Which Mixed-Member Proportional Electoral Formula Fits You Best? Assessing the Proportionality Principle of Positive Vote Transfer Systems

    DEFF Research Database (Denmark)

    Bochsler, Daniel

    2014-01-01

    Mixed-member proportional systems (MMP) are a family of electoral systems which combine district-based elections with a proportional seat allocation. Positive vote transfer systems belong to this family. This article explains why they might be better than their siblings, and examines under which ...

  13. Polycyclic aromatic hydrocarbons and black carbon in intertidal sediments of China coastal zones: Concentration, ecological risk, source and their relationship

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaofei [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Hou, Lijun [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Li, Ye [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Liu, Min, E-mail: mliu@geo.ecnu.edu.cn [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Lin, Xianbiao; Cheng, Lv [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China)

    2016-10-01

    Polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) have attracted many attentions, especially in the coastal environments. In this study, spatiotemporal distributions of PAHs and BC, and the correlations between BC and PAHs were investigated in the intertidal sediments of China coastal zones. BC in sediments was measured through dichromate oxidation (BC{sub Cr}) and thermal oxidation (BC{sub CTO}). The concentrations of BC{sub Cr} in the intertidal sediments ranged between 0.61 and 6.32 mg g{sup −1}, while BC{sub CTO} ranged between 0.57 and 4.76 mg g{sup −1}. Spatial variations of δ{sup 13}C signatures in TOC and BC were observed, varying from − 21.13‰ to − 24.87‰ and from − 23.53‰ to − 16.78‰, respectively. PAH contents of sediments ranged from 195.9 to 4610.2 ng g{sup −1} in winter and 98.2 to 2796.5 ng g{sup −1} in summer, and significantly seasonal variations were observed at most sampling sites. However, the results of potential toxicity assessment indicated low ecological risk in the intertidal sediments of China coastal zones. Greater concentrations of PAHs measured in the sediments of estuarine environments indicated that rivers runoff may have been responsible for the higher PAH pollution levels in the intertidal sediments of China coastal zones. Pearson's correlation analysis suggested that pyrogenic compounds of PAH were significantly related to BC, due to that both BC and these compounds derived mainly from the combustion process of fossil fuels and biomass. Overall, increasing energy consumptions caused by anthropogenic activities can contribute more emissions of BC as well as PAHs and thus improve the importance of BC in indicating pyrogenic compounds of PAHs in the intertidal sediments of China coastal zones. - Highlights: • River runoffs were responsible for the high PAH pollution levels in the study area. • BC and PAHs derived mainly from the combustion process of fossil fuels. • BC was associated

  14. The proportionate value of proportionality in palliative sedation.

    Science.gov (United States)

    Berger, Jeffrey T

    2014-01-01

    Proportionality, as it pertains to palliative sedation, is the notion that sedation should be induced at the lowest degree effective for symptom control, so that the patient's consciousness may be preserved. The pursuit of proportionality in palliative sedation is a widely accepted imperative advocated in position statements and guidelines on this treatment. The priority assigned to the pursuit of proportionality, and the extent to which it is relevant for patients who qualify for palliative sedation, have been overstated. Copyright 2014 The Journal of Clinical Ethics. All rights reserved.

  15. An integrated photosensor readout for gas proportional scintillation counters

    International Nuclear Information System (INIS)

    Lopes, J.A.M.; Santos, J.M.F. dos; Conde, C.A.N.

    1996-01-01

    A xenon gas proportional scintillation counter has been instrumented with a novel photosensor that replaces the photomultiplier tube normally used to detect the VUV secondary scintillation light. In this implementation, the collection grid of a planar gas proportional scintillation counter also functions as a multiwire proportional chamber to amplify and detect the photoelectrons emitted by a reflective CsI photocathode in direct contact with the xenon gas. This integrated concept combines greater simplicity, compactness, and ruggedness (no optical window is used) with low power consumption. An energy resolution of 12% was obtained for 59.6 keV x-rays

  16. Anthropogenic protection alters the microbiome in intertidal mangrove wetlands in Hainan Island.

    Science.gov (United States)

    Yun, Juanli; Deng, Yongcui; Zhang, Hongxun

    2017-08-01

    Intertidal mangrove wetlands are of great economic and ecological importance. The regular influence of tides has led to the microbial communities in these wetlands differing significantly from those in other habitats. In this study, we investigated the microbiomes of the two largest mangrove wetlands in Hainan Island, China, which have different levels of anthropogenic protection. Soil samples were collected from the root zone of 13 mangrove species. The microbial composition, including key functional groups, was assessed using Illumina sequencing. Bioinformatics analysis showed that there was a significant difference in the microbiomes between the protected Bamen Bay and the unprotected Dongzhai Bay. The overall microbiome was assigned into 78 phyla and Proteobacteria was the most abundant phylum at both sites. In the protected wetland, there were fewer marine-related microbial communities, such as sulfate-reducing bacteria, and more terrestrial-related communities, such as Verrucomicrobia methanotrophs. We also observed distinct microbial compositions among the different mangrove species at the protected site. Our data suggest that the different microbiomes of the two mangrove wetlands are the result of a complex interaction of the different environmental variables at the two sites.

  17. Late Holocene evolution of the Northeast intertidal region of Sepetiba Bay, Rio de Janeiro (Brazil

    Directory of Open Access Journals (Sweden)

    Anita Fernandes Souza Pinto

    2016-03-01

    Full Text Available This work is based on the study of the core T1 collected in the Guaratiba Mangrove, located on the northeastern margin of Sepetiba Bay. Few studies dealing with the application of benthic foraminifera to study sea level changes during the Holocene have been conducted in Sepetiba Bay, State of Rio de Janeiro, Brazil. In order to fill this gap, the core T1 was studied using textural, geochemical (carbonate, total organic carbon, total sulfur and stable isotopes evaluated in Ammonia tepida and microfaunal (benthic foraminifera data, unveiling paleoecological relationships of these organisms and the evolutionary scenario of Guaratiba Mangrove. Radiocarbon results indicate an estimated age of about 2400 yrs cal BP for the core base. Textural, geochemical and benthic foraminifera data suggest that the study area changed significantly during the last 2400 yrs cal BP. It experienced coastal waves action and shoreface processes in the period between ≈2.400-1.400 yrs cal BP; then, this phase gave place to a shallow marine environment similar to that found currently in internal and protected areas of Sepetiba Bay, between ≈1.400-350 yrs cal BP. Thenceforth, the study area evolved to the present mangrove environment. Factors related to climatic oscillations and the formation, evolution and events of rupture of Marambaia sand ridge influenced the late Holocene evolution of the northeast intertidal area of Sepetiba Bay.

  18. Increasing temperature decreases the predatory effect of the intertidal shanny Lipophrys pholis on an amphipod prey

    KAUST Repository

    South, J.

    2017-11-15

    Interactions between Lipophrys pholis and its amphipod prey Echinogammarus marinus were used to investigate the effect of changing water temperatures, comparing current and predicted mean summer temperatures. Contrary to expectations, predator attack rates significantly decreased with increasing temperature. Handling times were significantly longer at 19° C than at 17 and 15° C and the maximum feeding estimate was significantly lower at 19° C than at 17° C. Functional-response type changed from a destabilizing type II to the more stabilizing type III with a temperature increase to 19° C. This suggests that a temperature increase can mediate refuge for prey at low densities. Predatory pressure by teleosts may be dampened by a large increase in temperature (here from 15 to 19° C), but a short-term and smaller temperature increase (to 17° C) may increase destabilizing resource consumption due to high maximum feeding rates; this has implications for the stability of important intertidal ecosystems during warming events.

  19. Hyperspectral imaging of the microscale distribution and dynamics of microphytobenthos in intertidal sediments

    KAUST Repository

    Chennu, Arjun; Fä rber, Paul; Volkenborn, Nils; Alnajjar, Mohammad Ahmad; Janssen, Felix; de Beer, Dirk; Polerecky, Lubos

    2013-01-01

    We describe a novel, field-deployable hyperspectral imaging system, called Hypersub, that allows noninvasive in situ mapping of the microphytobenthos (MPB) biomass distribution with a high spatial (sub-millimeter) and temporal (minutes) resolution over areas of 1 × 1 m. The biomass is derived from a log-transformed and near-infrared corrected reflectance hyperspectral index, which exhibits a linear relationship (R2 > 0.97) with the chlorophyll a (Chl a) concentration in the euphotic zone of the sediment and depends on the sediment grain size. Deployments of the system revealed that due to factors such as sediment topography, bioturbation, and grazing, the distribution of MPB in intertidal sediments is remarkably heterogeneous, with Chl a concentrations varying laterally by up to 400% of the average value over a distance of 1 cm. Furthermore, due to tidal cycling and diel light variability, MPB concentrations in the top 1 mm of sediments are very dynamic, changing by 40–80% over a few hours due to vertical migration. We argue that the high-resolution hyperspectral imaging method overcomes the inadequate resolution of traditional methods based on sedimentary Chl a extraction, and thus helps improve our understanding of the processes that control benthic primary production in coastal sediments.

  20. Bioremediation of the oil spill polluted marine intertidal zone and its toxicity effect on microalgae.

    Science.gov (United States)

    Pi, Yongrui; Xu, Nana; Bao, Mutai; Li, Yiming; Lv, Dong; Sun, Peiyan

    2015-04-01

    Custom-designed devices with 0.6 m (L) × 0.3 m (W) × 0.4 m (H) and a microbial consortium were applied to simulate bioremediation on the oil spill polluted marine intertidal zone. After the bioremediation, the removal efficiency of n-alkanes and polycyclic aromatic hydrocarbon homologues in crude oil evaluated by GC-MS were higher than 58% and 41% respectively. Besides, the acute toxicity effects of crude oil on three microalgae, i.e. Dicrateria sp., Skeletonema costatum and Phaeodactylum tricornutum, varied with concentration. The effects of microbe and surfactant treated water on the three microalgae followed a decreasing order: the microbial consortium plus Tween-80 > the microbial consortium > Tween-80. During 96 h, the cell densities of the three microalgae in treated seawater increased from 4.0 × 10(5), 1.0 × 10(5) and 2.5 × 10(5) cells per mL to 1.7 × 10(6), 8.5 × 10(5) and 2.5 × 10(6) cells per mL, respectively, which illustrated that the quality of seawater contaminated by crude oil was significantly improved by the bioremediation.

  1. Applications of three DNA barcodes in assorting intertidal red macroalgal flora in Qingdao, China

    Science.gov (United States)

    Zhao, Xiaobo; Pang, Shaojun; Shan, Tifeng; Liu, Feng

    2013-03-01

    This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult solely depending on morphological characteristics. In recent years, DNA barcode technique has become a more and more effective tool to help solve some of the taxonomic difficulties. Some DNA markers such as COI (cytochrome oxidase subunit I) are proposed as standardized DNA barcodes for all seaweed species. In this study, COI, UPA (universal plastid amplicon, domain V of 23S rRNA), and ITS (nuclear internal transcribed spacer) were employed to analyze common species of intertidal red seaweeds in Qingdao (119.3°-121°E, 35.35°-37.09°N). The applicability of using one or a few combined barcodes to identify red seaweed species was tested. The results indicated that COI is a sensitive marker at species level. However, not all the tested species gave PCR amplification products due to lack of the universal primers. The second barcode UPA had effective universal primers but needed to be tested for the effectiveness of resolving closely related species. More than one ITS sequence types were found in some species in this investigation, which might lead to confusion in further analysis. Therefore ITS sequence is not recommended as a universal barcode for seaweeds identification.

  2. Facing the Heat: Does Desiccation and Thermal Stress Explain Patterns of Orientation in an Intertidal Invertebrate?

    Science.gov (United States)

    Fraser, Clarissa M L; Seebacher, Frank; Lathlean, Justin; Coleman, Ross A

    2016-01-01

    A key challenge for ecologists is to quantify, explain and predict the ecology and behaviour of animals from knowledge of their basic physiology. Compared to our knowledge of many other types of distribution and behaviour, and how these are linked to individual function, we have a poor level of understanding of the causal basis for orientation behaviours. Most explanations for patterns of animal orientation assume that animals will modify their exposure to environmental factors by altering their orientation. We used a keystone grazer on rocky shores, the limpet Cellana tramoserica, to test this idea. Manipulative experiments were done to evaluate whether orientation during emersion affected limpet desiccation or body temperature. Body temperature was determined from infrared thermography, a technique that minimises disturbance to the test organism. No causal relationships were found between orientation and (i) level of desiccation and (ii) their body temperature. These results add to the growing knowledge that responses to desiccation and thermal stress may be less important in modifying the behaviour of intertidal organisms than previously supposed and that thermoregulation does not always reflect patterns of animal orientation. Much of what we understand about orientation comes from studies of animals able to modify orientation over very short time scales. Our data suggests that for animals whose location is less flexible, orientation decisions may have less to do with responses to environmental factors and more to do with structural habitat properties or intrinsic individual attributes. Therefore we suggest future studies into processes affecting orientation must include organisms with differing levels of behavioural plasticity.

  3. Nitrogen Fixation in the Intertidal Sediments of the Yangtze Estuary: Occurrence and Environmental Implications

    Science.gov (United States)

    Hou, Lijun; Wang, Rong; Yin, Guoyu; Liu, Min; Zheng, Yanling

    2018-03-01

    Nitrogen fixation is a microbial-mediated process converting atmospheric dinitrogen gas to biologically available ammonia or other molecules, and it plays an important role in regulating nitrogen budgets in coastal marine ecosystems. In this study, nitrogen fixation in the intertidal sediments of the Yangtze Estuary was investigated using nitrogen isotope tracing technique. The abundance of nitrogen fixation functional gene (nifH) was also quantified. The measured rates of sediment nitrogen fixation ranged from 0.37 to 7.91 nmol N g-1 hr-1, while the abundance of nifH gene varied from 2.28 × 106 to 1.28 × 108 copies g-1 in the study area. The benthic nitrogen fixation was correlated closely to the abundance of nifH gene and was affected significantly by salinity, pH, and availability of sediment organic carbon and ammonium. It is estimated that sediment nitrogen fixation contributed approximately 9.3% of the total terrigenous inorganic nitrogen transported annually into the Yangtze estuarine and coastal environment. This result implies that the occurrence of benthic nitrogen fixation acts as an important internal source of reactive nitrogen and to some extent exacerbates nitrogen pollution in this aquatic ecosystem.

  4. Aquatic respiration as a potential survival mechanism of Brephidium pseudofea (Lepidoptera: Lycaenidae) larvae to intertidal environments.

    Science.gov (United States)

    Warren, V; Daniels, J C; Hahn, D A

    2011-10-01

    The eastern pygmy blue, Brephidium pseudofea (Morrison) (Lepidoptera: Lycaenidae: Polyommatinae), inhabits intertidal environments that are periodically flooded. The immature stages are subject to salt or brackish water inundation during this time and therefore must endure many stressors, including respiratory limitation and salt exposure. Our goal was to investigate possible mechanisms used by the larval stages of B. pseudofea to endure periodic tidal inundation by using physiological and morphological analyses in comparison with several species of terrestrial lepidopteran larvae. A review of tidal charts showed that the immature stages of B. pseudofea would be prone to complete inundation two to five times per month during the summer months (May to August) and partial submersion for up to 20 d per month during the rest of the year. Larvae of several terrestrial lepidopteran species studied consumed oxygen under water for a limited period, but B. pseudofea demonstrated substantially higher oxygen consumption. Light microscopy of B. pseudofea larvae revealed small air pockets in and around the spiracles when submerged in tap water; these air pockets disappeared when exposed to detergent solution. The resulting air pockets may function as a diffusion layer for oxygen to be absorbed from the surrounding water or may act in conjunction with trans-cuticular gas exchange to meet the larva's respiratory needs. Morphological examination by scanning electron microscopy showed that B. psudofea larvae have distinctively small, clavate setae that appear insufficient to effectively support a functional plastron.

  5. A new species of Parodontophora (Nematoda: Axonolaimidae) from the intertidal zone of the East China Sea

    Science.gov (United States)

    Wang, Haixia; Huang, Yong

    2016-02-01

    This study described a new species of free-living nematode discovered in the intertidal mudflat of Ximen Island, East China Sea. The new species, designated Parodontophora longiamphidata sp. nov., was characterized by a cylindrical body with tapering extremeties; cuticle smooth without somatic setae; four short cephalic setae; cylindrical buccal cavity with six clawlike teeth at the top of stoma; pharynx cylindrical with widened base; amphidial fovea crook-shaped with elongated scalariform branch extending past level of base of pharynx and ventral gland; ventral gland cell long-oval shaped located posterior to pharyngo-intestinal junction; excretory pore at level of middle of buccal cavity; tail conico-cylindrical with enlarged tip; three caudal gland cells, male spicules arched with cephalic proximal end and tapered distal end; gubernaculum with dorso-caudal apophysis; female with two opposed outstretched ovaries; and vulva at slightly post-midpoint of body length. This new species was close to P. wuleidaowanensis Zhang, 2005 and P. polita Gerlach, 1955 in terms of long amphidial fovea branch. The newly found species was easily distinguishable from the two documented; its amphidial fovea branch (255-290 µm versus 72-106 and 125-150 µm) was obviously longer. Key to the Parodontophora species with a longer amphidial fovea branch was given.

  6. Increasing temperature decreases the predatory effect of the intertidal shanny Lipophrys pholis on an amphipod prey

    KAUST Repository

    South, J.; Welsh, D.; Anton, A.; Sigwart, J. D.; Dick, J. T. A.

    2017-01-01

    Interactions between Lipophrys pholis and its amphipod prey Echinogammarus marinus were used to investigate the effect of changing water temperatures, comparing current and predicted mean summer temperatures. Contrary to expectations, predator attack rates significantly decreased with increasing temperature. Handling times were significantly longer at 19° C than at 17 and 15° C and the maximum feeding estimate was significantly lower at 19° C than at 17° C. Functional-response type changed from a destabilizing type II to the more stabilizing type III with a temperature increase to 19° C. This suggests that a temperature increase can mediate refuge for prey at low densities. Predatory pressure by teleosts may be dampened by a large increase in temperature (here from 15 to 19° C), but a short-term and smaller temperature increase (to 17° C) may increase destabilizing resource consumption due to high maximum feeding rates; this has implications for the stability of important intertidal ecosystems during warming events.

  7. Vertical distribution and seasonality of peracarid crustaceans associated with intertidal macroalgae

    Science.gov (United States)

    Guerra-García, J. M.; Baeza-Rojano, E.; Cabezas, M. P.; García-Gómez, J. C.

    2011-02-01

    Spatial patterns and seasonal fluctuations of intertidal peracarids from Tarifa Island, Strait of Gibraltar, were studied over a two-year period (December 2005-December 2007). A total of 25,749 individuals were collected, comprising 46 species. Amphipods were best represented in the total number of species (32) and individuals (89% of numerical abundance) followed by isopods (12 species and 11% abundance) and tanaids (2 species and 1%). The highest number of species was registered in intermediate levels (1-1.5 m) dominated by Corallina elongata, although the highest abundances of peracarids were associated to seaweeds of lower levels (0-1 m) such as Gelidium corneum, Osmundea pinnatifida, Valonia utricularis and a turf of Caulacanthus ustulatus. The most abundant peracarids, Hyale stebbingi, H. schmidti, H. perieri, Stenothoe monoculoides, Caprella penantis, C. grandimana, Dynamene edwardsii and Ischyromene lacazei, were present throughout the whole year during 2006 and 2007. The highest peracarid densities were measured in April-August coinciding with the highest development of seaweeds, just before the maximum values of water temperature measured at the end of summer. Multivariate analyses confirmed a clear zonation of algae and associated peracarids in a vertical gradient, which was maintained stable during the two-year study. Several physical and biological factors may regulate such patterns of peracarid abundance and future experimental studies are necessary to explore the importance of factors such as competition, predation or weather conditions.

  8. Hyperspectral imaging of the microscale distribution and dynamics of microphytobenthos in intertidal sediments

    KAUST Repository

    Chennu, Arjun

    2013-10-03

    We describe a novel, field-deployable hyperspectral imaging system, called Hypersub, that allows noninvasive in situ mapping of the microphytobenthos (MPB) biomass distribution with a high spatial (sub-millimeter) and temporal (minutes) resolution over areas of 1 × 1 m. The biomass is derived from a log-transformed and near-infrared corrected reflectance hyperspectral index, which exhibits a linear relationship (R2 > 0.97) with the chlorophyll a (Chl a) concentration in the euphotic zone of the sediment and depends on the sediment grain size. Deployments of the system revealed that due to factors such as sediment topography, bioturbation, and grazing, the distribution of MPB in intertidal sediments is remarkably heterogeneous, with Chl a concentrations varying laterally by up to 400% of the average value over a distance of 1 cm. Furthermore, due to tidal cycling and diel light variability, MPB concentrations in the top 1 mm of sediments are very dynamic, changing by 40–80% over a few hours due to vertical migration. We argue that the high-resolution hyperspectral imaging method overcomes the inadequate resolution of traditional methods based on sedimentary Chl a extraction, and thus helps improve our understanding of the processes that control benthic primary production in coastal sediments.

  9. Community size and composition of ammonia oxidizers and denitrifiers in an alluvial intertidal wetland ecosystem

    Directory of Open Access Journals (Sweden)

    Ziye eHu

    2014-07-01

    Full Text Available Global nitrogen cycling is mainly mediated by the activity of microorganisms. Nitrogen cycle processes are mediated by functional groups of microorganisms that are affected by constantly changing environmental conditions and substrate availability. In this study, we investigated the temporal and spatial patterns of nitrifier and denitrifier communities in an intertidal wetland. Soil samples were collected over four distinct seasons from three locations with different vegetative cover. Multiple environmental factors and process rates were measured and analyzed together with the community size and composition profiles. We observed that the community size and composition of the nitrifiers and denitrifiers are affected significantly by seasonal factors, while vegetative cover affected the community composition. The seasonal impacts on the community size of ammonia oxidizing archaea (AOA are much higher than that of ammonia oxidizing bacteria (AOB. The seasonal change was a more important indicator for AOA community composition patterns, while vegetation was more important for the AOB community patterns. The microbial process rates were correlated with both the community size and composition.

  10. Gas seepage on an intertidal site: Torry Bay, Firth of Forth, Scotland

    Energy Technology Data Exchange (ETDEWEB)

    Judd, A.G.; Sim, R.; Kingston, P.; McNally, J. [University of Sunderland, Sunderland (United Kingdom)

    2002-07-01

    Gas seeps occurring on tidal flats on the northern shore of the inner Firth of Forth are described. The principal gas is methane, which is considered to come from the coal-bearing rocks of the Lower Limestone Series (Carboniferous); either naturally or from abandoned coal workings. Seep activity has been known, at the site for several years, and it is suggested that the presence of white filamentous bacteria (Beggiatoa sp.) and a carbonate precipitate are indicative of long-term seepage. Comparative studies at the seep and at a control site revealed that the seeps have only a marginal effect on the intertidal fauna. Migration of gas through the thin ({lt} 2 m) surficial sediments appears to be controlled by the topography of a gravel layer, seeps preferentially occurring where the top of the gravel is closest to the surface. The total gas emission from 70 to 100 individual seepage vents is estimated at approximate to 1 tonne CH{sub 4} yr{sup -1}, the majority of which is emitted direct to the atmosphere.

  11. Functional and structural characterization of a eurytolerant calsequestrin from the intertidal teleost Fundulus heteroclitus.

    Directory of Open Access Journals (Sweden)

    A Carl Whittington

    Full Text Available Calsequestrins (CSQ are high capacity, medium affinity, calcium-binding proteins present in the sarcoplasmic reticulum (SR of cardiac and skeletal muscles. CSQ sequesters Ca²⁺ during muscle relaxation and increases the Ca²⁺-storage capacity of the SR. Mammalian CSQ has been well studied as a model of human disease, but little is known about the environmental adaptation of CSQ isoforms from poikilothermic organisms. The mummichog, Fundulus heteroclitus, is an intertidal fish that experiences significant daily and seasonal environmental fluctuations and is an interesting study system for investigations of adaptation at the protein level. We determined the full-length coding sequence of a CSQ isoform from skeletal muscle of F. heteroclitus (FCSQ and characterized the function and structure of this CSQ. The dissociation constant (K(d of FCSQ is relatively insensitive to changes in temperature and pH, thus indicating that FCSQ is a eurytolerant protein. We identified and characterized a highly conserved salt bridge network in FCSQ that stabilizes the formation of front-to-front dimers, a process critical to CSQ function. The functional profile of FCSQ correlates with the natural history of F. heteroclitus suggesting that the eurytolerant function of FCSQ may be adaptive.

  12. Habitat use by Atherinella brasiliensis (Quoy & Gaimard, 1825 in intertidal zones of a subtropical estuary, Brazil

    Directory of Open Access Journals (Sweden)

    Barbara Maichak de Carvalho

    2015-08-01

    Full Text Available Habitat use is different along the ontogenetic development of some species and may be influenced by environmental parameters. This study described the interaction of Atherinella brasiliensis caught in intertidal areas of the Paranaguá Estuarine Complex with environmental parameters. We caught 10024 individuals between August 2010 and July 2011, with total mean length of 44.32 mm (SD ± 25.37 mm, variation range between 12 and 142 mm, and weight between 0.01 and 73 g, averaging 1.35 g (SD ± 2.66 g and ages estimated between < 1 and 22 months. Significant differences were detected between sectors and periods for number of individuals and weight at capture, with higher mean values in the mean sector during the rainy period. The spatial and temporal distribution of ages was statistically different, individuals between < 1 and 3 months were more abundant in the sector 2 during the rainy period, and individuals older than 7 months were evenly distributed throughout the sampling area, and with higher mean abundance at the beginning and end of the dry period. Environmental variables that most influenced the distribution of age classes were temperature and salinity.

  13. Identification and molecular characterization of nitric oxide synthase (NOS) gene in the intertidal copepod Tigriopus japonicus.

    Science.gov (United States)

    Jeong, Chang-Bum; Kang, Hye-Min; Seo, Jung Soo; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

    2016-02-10

    In copepods, no information has been reported on the structure or molecular characterization of the nitric oxide synthase (NOS) gene. In the intertidal copepod Tigriopus japonicus, we identified a NOS gene that is involved in immune responses of vertebrates and invertebrates. In silico analyses revealed that nitric oxide (NO) synthase domains, such as the oxygenase and reductase domains, are highly conserved in the T. japonicus NOS gene. The T. japonicus NOS gene was highly transcribed in the nauplii stages, implying that it plays a role in protecting the host during the early developmental stages. To examine the involvement of the T. japonicus NOS gene in the innate immune response, the copepods were exposed to lipopolysaccharide (LPS) and two Vibrio sp. After exposure to different concentrations of LPS and Vibrio sp., T. japonicus NOS transcription was significantly increased over time in a dose-dependent manner, and the NO/nitrite concentration increased as well. Taken together, our findings suggest that T. japonicus NOS transcription is induced in response to an immune challenge as part of the conserved innate immunity. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Compound eye adaptations for diurnal and nocturnal lifestyle in the intertidal ant, Polyrhachis sokolova.

    Directory of Open Access Journals (Sweden)

    Ajay Narendra

    Full Text Available The Australian intertidal ant, Polyrhachis sokolova lives in mudflat habitats and nests at the base of mangroves. They are solitary foraging ants that rely on visual cues. The ants are active during low tides at both day and night and thus experience a wide range of light intensities. We here ask the extent to which the compound eyes of P. sokolova reflect the fact that they operate during both day and night. The ants have typical apposition compound eyes with 596 ommatidia per eye and an interommatidial angle of 6.0°. We find the ants have developed large lenses (33 µm in diameter and wide rhabdoms (5 µm in diameter to make their eyes highly sensitive to low light conditions. To be active at bright light conditions, the ants have developed an extreme pupillary mechanism during which the primary pigment cells constrict the crystalline cone to form a narrow tract of 0.5 µm wide and 16 µm long. This pupillary mechanism protects the photoreceptors from bright light, making the eyes less sensitive during the day. The dorsal rim area of their compound eye has specialised photoreceptors that could aid in detecting the orientation of the pattern of polarised skylight, which would assist the animals to determine compass directions required while navigating between nest and food sources.

  15. Forecasting the poleward range expansion of an intertidal species driven by climate alterations

    Directory of Open Access Journals (Sweden)

    Raquel Xavier

    2010-11-01

    Full Text Available Accurate distributional models can be used to reliably predict the response of organisms to climatic changes. Though such models have been extensively applied to terrestrial organisms, they have hardly ever been applied to the marine environment. Recent changes in the distribution of the marine gastropod Patella rustica (L. were previously modelled with Classification and Regression Tree (CART and the results revealed that increases in temperature were the major driver of those changes. However, the accuracy scores during the validation of the model were unsatisfactory, preventing its use for forecasting purposes. To fulfil this objective, in the present study a more robust method, Artificial Neural Network (ANN, was employed to produce a model suited to forecasting changes in the distribution of P. rustica. Results confirmed that the ANN model behaved better than the CART, and that it could be used for forecasting future distributional scenarios. The model forecasts that by the 2020s P. rustica is likely to expand its range at least 1000 km northwards. These results should be interpreted with caution considering the dispersal limitations of this species, but if such an expansion took place, major changes in the colonized ecosystems are expected due to the key role of limpets in intertidal communities.

  16. Degradation and mineralization of the polycyclic aromatic hydrocarbons anthracene and naphthalene in intertidal marine sediments

    International Nuclear Information System (INIS)

    Bauer, J.E.; Capone, D.G.

    1985-01-01

    The degradation of the polynuclear aromatic hydrocarbons (PAHs) anthracene and naphthalene by the microbiota of intertidal sediments was investigated in laboratory studies. No mineralization of either PAH was observed in the absence of oxygen. Both rates and total amounts of PAH mineralization were strongly controlled by oxygen content and temperature of the incubations. Inorganic nitrogen and glucose amendments had minimal effects on PAH mineralization. The rates and total amounts of PAH mineralized were directly related to compound concentration, pre-exposure time, and concentration. Maximum mineralization was observed at the higher concentrations (5 to 100 μg/g [ppm]) of both PAHs. Optimal acclimation to anthracene and naphthalene (through pre-exposures to the compounds) occurred at the highest acclimation concentration (1,000 ppm). However, acclimation to a single concentration (100 ppm) resulted in initial relative mineralization rates over a range of re-exposure concentrations (1 to 1,000 ppm) being nearly identical. Maximum mineralization of both PAHs occurred after intermediate periods (1 to 2 weeks) of pre-exposure. The fraction of the total heterotrophic population capable of utilizing anthracene or naphthalene as sole carbon source was also greatest after 2 weeks

  17. Plutonium in intertidal coastal and estuarine sediments in the Northern Irish Sea

    International Nuclear Information System (INIS)

    Aston, S.R.; Assinder, D.J.; Kelly, M.

    1985-01-01

    Surface intertidal sediments from 35 sites in the Irish Sea have been analysed for their 238 Pu and sup(239,240)Pu activities, together with an intensive study of plutonium in sediments of the Esk Estuary (NW England). The range of plutonium activities for the whole survey were 0.14-4118 and 1.3-16 026 Bq kg -1 for 238 Pu and sup(239,240)Pu, respectively. The levels of Pu activity, derived from the Sellafield nuclear fuel reprocessing effluents, in sediments are controlled by lithological factors and the influence of transport and post-depositional processes. Grain size distribution is particularly important, the major part of plutonium activity being in the mud fraction of all sediments. The data suggest that over the Irish Sea coastline, dynamic mixing of sediment grains by reworking and resuspension and/or by dispersion in tidal currents are important in determining plutonium distributions. The exponential decrease in sediment plutonium activities away from the Sellafield source is attributed to the progressive mixing with older contaminated and uncontaminated sediments. (author)

  18. Desiccation induces accumulations of antheraxanthin and zeaxanthin in intertidal macro-alga Ulva pertusa (Chlorophyta.

    Directory of Open Access Journals (Sweden)

    Xiujun Xie

    Full Text Available For plants and algae, exposure to high light levels is deleterious to their photosynthetic machineries. It also can accelerate water evaporation and thus potentially lead to drought stress. Most photosynthetic organisms protect themselves against high light caused photodamages by xanthophyll cycle-dependent thermal energy dissipation. It is generally accepted that high light activates xanthophyll cycle. However, the relationship between xanthophyll cycle and drought stress remains ambiguous. Herein, Ulva pertusa (Chlorophyta, a representative perennial intertidal macro-algae species with high drought-tolerant capabilities and simple structures, was used to investigate the operation of xanthophyll cycle during desiccation in air. The results indicate that desiccation under dim light induced accumulation of antheraxanthin (Ax and zeaxanthin (Zx at the expense of violaxanthin (Vx. This accumulation could be arrested by dithiothreitol completely and by uncoupler (carbonyl cyanide p-trifluoromethoxyphenylhydrazone partially, implying the participation of Vx de-epoxidase in conversion of Vx to Ax and Zx. Treatment with inhibitors of electron transport along thylakoid membrane, e.g. DCMU, PG and DBMIB, did not significantly arrest desiccation-induced accumulation of Ax and Zx. We propose that for U. pertusa, besides excess light, desiccation itself could also induce accumulation of Ax and Zx. This accumulation could proceed without electron transport along thylakoid membrane, and is possibly resulting from the reduction of thylakoid lumen volume during desiccation. Considering the pleiotropic effects of Ax and Zx, accumulated Ax and Zx may function in protecting thylakoid membrane and enhancing thermal quenching during emersion in air.

  19. A reduced feedback proportional fair multiuser scheduling scheme

    KAUST Repository

    Shaqfeh, Mohammad; Alnuweiri, Hussein M.; Alouini, Mohamed-Slim

    2011-01-01

    . A slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we propose a novel proportional fair multiuser switched

  20. DC motor proportional control system for orthotic devices

    Science.gov (United States)

    Blaise, H. T.; Allen, J. R.

    1972-01-01

    Multi-channel proportional control system for operation of dc motors for use with externally-powered orthotic arm braces is described. Components of circuitry and principles of operation are described. Schematic diagram of control circuit is provided.

  1. Proportional feedback control of laminar flow over a hemisphere

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Il [Dept. of Mechanical Engineering, Ajou University, Suwon (Korea, Republic of); Son, Dong Gun [Severe Accident and PHWR Safety Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon (Korea, Republic of)

    2016-08-15

    In the present study, we perform a proportional feedback control of laminar flow over a hemisphere at Re = 300 to reduce its lift fluctuations by attenuating the strength of the vortex shedding. As a control input, blowing/suction is distributed on the surface of hemisphere before the separation, and its strength is linearly proportional to the transverse velocity at a sensing location in the centerline of the wake. The sensing location is determined based on a correlation function between the lift force and the time derivative of sensing velocity. The optimal proportional gains for the proportional control are obtained for the sensing locations considered. The present control successfully attenuates the velocity fluctuations at the sensing location and three dimensional vertical structures in the wake, resulting in the reduction of lift fluctuations of hemisphere.

  2. Operability test report for 211BA flow proportional sampler

    International Nuclear Information System (INIS)

    Weissenfels, R.D.

    1995-01-01

    This operability report will verify that the 211-BA flow proportional sampler functions as intended by design. The sampler was installed by Project W-007H and is part of BAT/AKART for the BCE liquid effluent stream

  3. A parsimonious model for the proportional control valve

    OpenAIRE

    Elmer, KF; Gentle, CR

    2001-01-01

    A generic non-linear dynamic model of a direct-acting electrohydraulic proportional solenoid valve is presented. The valve consists of two subsystems-s-a spool assembly and one or two unidirectional proportional solenoids. These two subsystems are modelled separately. The solenoid is modelled as a non-linear resistor-inductor combination, with inductance parameters that change with current. An innovative modelling method has been used to represent these components. The spool assembly is model...

  4. Reduction of degraded events in miniaturized proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Plaga, R.; Kirsten, T. (Max Planck Inst. fuer Kernphysik, Heidelberg (Germany))

    1991-11-15

    A method to reduce the number of degraded events in miniaturized proportional counters is described. A shaping of the outer cathode leads to a more uniform gas gain along the counter axis. The method is useful in situations in which the total number of decay events is very low. The effects leading to degraded events are studied theoretically and experimentally. The usefulness of the method is demonstrated by using it for the proportional counter of the GALLEX solar neutrino experiment. (orig.).

  5. Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae, a parasite of the intertidal bug, Saldula laticollis (Reuter(Hemiptera: Saldidae on the Oregon coast

    Directory of Open Access Journals (Sweden)

    Poinar George O

    2012-02-01

    Full Text Available Abstract Background It is rare to find terrestrial nematode lineages parasitizing arthropods inhabiting the intertidal or littoral zone of the oceans. During an ecological study along the Oregon dunes, an allantonematid nematode (Tylenchomorpha: Allantonematidae was discovered parasitizing the intertidal shore bug, Saldula laticollis (Reuter(Hemiptera: Saldidae. This shore bug is adapted to an intertidal environment and can survive short periods of submergence during high tides. The present study describes the nematode parasite and discusses aspects of its development, ecology and evolution. Methods Adults and last instar nymphs of S. laticollis (Hemiptera: Saldidae were collected from the high intertidal zone among clumps of Juncus L. (Juncaceae plants at Waldport, Oregon on October 3, 2011. The bugs were dissected in 1% saline solution and the nematodes killed in 1% Ringers solution and immediately fixed in 5% formalin (at 20°C. Third stage juveniles removed from infected hosts were maintained in 1% saline solution until they matured to the adult stage, molted and mated. Results Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae is described from last instar nymphs and adults of the intertidal bug, Saldula laticollis on the Oregon coast. The new genus can be distinguished from other genera in the Allantonematidae by a stylet lacking basal knobs in both sexes, an excretory pore located behind the nerve ring, ribbed spicules, a gubernaculum, the absence of a bursa and the elongate-tubular shape of the ovoviviparous parasitic females. Studies of the organogenesis of Halophilanema showed development to third stage juveniles in the uterus of parasitic females. Maturation to the free-living adults and mating occurred in the environment. The incidence of infection of S. laticollis ranged from 0% to 85% depending on the microhabitat in the intertidal zone. Conclusions Based on the habitat and morphological characters, it is proposed

  6. Against proportional shortfall as a priority-setting principle.

    Science.gov (United States)

    Altmann, Samuel

    2018-05-01

    As the demand for healthcare rises, so does the need for priority setting in healthcare. In this paper, I consider a prominent priority-setting principle: proportional shortfall. My purpose is to argue that proportional shortfall, as a principle, should not be adopted. My key criticism is that proportional shortfall fails to consider past health.Proportional shortfall is justified as it supposedly balances concern for prospective health while still accounting for lifetime health, even though past health is deemed irrelevant. Accounting for this lifetime perspective means that the principle may indirectly consider past health by accounting for how far an individual is from achieving a complete, healthy life. I argue that proportional shortfall does not account for this lifetime perspective as it fails to incorporate the fair innings argument as originally claimed, undermining its purported justification.I go on to demonstrate that the case for ignoring past health is weak, and argue that past health is at least sometimes relevant for priority-setting decisions. Specifically, when an individual's past health has a direct impact on current or future health, and when one individual has enjoyed significantly more healthy life years than another.Finally, I demonstrate that by ignoring past illnesses, even those entirely unrelated to their current illness, proportional shortfall can lead to instances of double jeopardy, a highly problematic implication. These arguments give us reason to reject proportional shortfall. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. The principle of proportionality revisited: interpretations and applications.

    Science.gov (United States)

    Hermerén, Göran

    2012-11-01

    The principle of proportionality is used in many different contexts. Some of these uses and contexts are first briefly indicated. This paper focusses on the use of this principle as a moral principle. I argue that under certain conditions the principle of proportionality is helpful as a guide in decision-making. But it needs to be clarified and to be used with some flexibility as a context-dependent principle. Several interpretations of the principle are distinguished, using three conditions as a starting point: importance of objective, relevance of means, and most favourable option. The principle is then tested against an example, which suggests that a fourth condition, focusing on non-excessiveness, needs to be added. I will distinguish between three main interpretations of the principle, some primarily with uses in research ethics, others with uses in other areas of bioethics, for instance in comparisons of therapeutic means and ends. The relations between the principle of proportionality and the precautionary principle are explored in the following section. It is concluded that the principles are different and may even clash. In the next section the principle of proportionality is applied to some medical examples drawn from research ethics and bioethics. In concluding, the status of the principle of proportionality as a moral principle is discussed. What has been achieved so far and what remains to be done is finally summarized.

  8. A reduced feedback proportional fair multiuser scheduling scheme

    KAUST Repository

    Shaqfeh, Mohammad

    2011-12-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed and ordered scheduling mechanism. A slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we propose a novel proportional fair multiuser switched-diversity scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the per-user feedback thresholds. We demonstrate by numerical examples that our reduced feedback proportional fair scheduler operates within 0.3 bits/sec/Hz from the achievable rates by the conventional full feedback proportional fair scheduler in Rayleigh fading conditions. © 2011 IEEE.

  9. Prospective Teachers Proportional Reasoning and Presumption of Student Work

    Directory of Open Access Journals (Sweden)

    Mujiyem Sapti

    2015-08-01

    Full Text Available This study aimed to describe the proportional reasoning of prospective teachers and their predictions about students' answers. Subjects were 4 prospective teacher  7th semester Department of Mathematics Education, Muhammadiyah University of Purworejo. Proportional reasoning task used to obtain research data. Subjects were asked to explain their reasoning and write predictions of student completion. Data was taken on October 15th, 2014. Interviews were conducted after the subjects completed the task and recorded with audio media. The research data were subject written work and interview transcripts. Data were analyzed using qualitative analysis techniques. In solving the proportional reasoning task, subjects using the cross product. However, they understand the meaning of the cross product. Subject also could predict students' reasoning on the matter.

  10. Proton-recoil proportional counter tests at TREAT

    International Nuclear Information System (INIS)

    Fink, C.L.; Eichholz, J.J.; Burrows, D.R.; DeVolpi, A.

    1979-01-01

    A methane filled proton-recoil proportional counter will be used as a fission neutron detector in the fast-neutron hodoscope. To provide meaningful fuel-motion information the proportional counter should have: a linear response over a wide range of reactor powers background ratio (the number of high energy neutrons detected must be maximized relative to low energy neutrons, and gamma ray sensitivity must be kept small); and a detector efficiency for fission neutrons above 1 MeV of approximately 1%. In addition, it is desirable that the detector and the associated amplifier/discriminator be capable of operating at counting rates in excess of 500 kHz. This paper reports on tests that were conducted on several proportional counters at the TREAT reactor

  11. Multiaxial low cycle fatigue life under non-proportional loading

    International Nuclear Information System (INIS)

    Itoh, Takamoto; Sakane, Masao; Ohsuga, Kazuki

    2013-01-01

    A simple and clear method of evaluating stress and strain ranges under non-proportional multiaxial loading where principal directions of stress and strain are changed during a cycle is needed for assessing multiaxial fatigue. This paper proposes a simple method of determining the principal stress and strain ranges and the severity of non-proportional loading with defining the rotation angles of the maximum principal stress and strain in a three dimensional stress and strain space. This study also discusses properties of multiaxial low cycle fatigue lives for various materials fatigued under non-proportional loadings and shows an applicability of a parameter proposed by author for multiaxial low cycle fatigue life evaluation

  12. Competitive interactions among zoanthids (cnidaria: zoanthidae in an intertidal zone of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Emanuelle Fontenele Rabelo

    2013-03-01

    Full Text Available Sessile organisms that live in consolidated substrates frequently compete for space. Coral species have many strategies to face this competition, including harming their opponents or hindering their growth. In the present study, the competitive interactions between three species of zoanthids were investigated in the intertidal zone of a sandstone reef environment in northeastern Brazil. The competitive abilities of the three species were evaluated by periodic observation of the natural fringes of contact and experimental evaluation of their growth rate through removal of 100 cm² of colonies of each species. Palythoa caribaeorum and Zoanthus sociatus had similar growth rates, and both species grew faster than Protopalythoa variabilis. The recolonization strategy seems to differ among species. The contact fringes between P. caribaeorum and Z. sociatus remained unchanged over time, without any type of aggressive interaction between them, suggesting that stand-off was the strategy used by these organisms. Palythoa caribaeorum and Z. sociatus grew among the polyps of P. variabilis, often killing its colonies. The coexistence of zoanthids reveals a capacity for survival in the face of competition for limited resources such as free substrate, which led to the colonization and establishment of zoanthids in intertidal environments.A competição por espaço é comum em organismos sésseis que vivem em substrato consolidado. Os corais apresentam muitas estratégias para competição por espaço, incluindo danos ao oponente ou inibição do crescimento. No presente estudo, as interações competitivas entre três espécies de zoantídeos foram investigadas em um ambiente de recifes de arenito no nordeste brasileiro. As habilidades competitivas dos zoantídeos foram analisadas por observações periódicas das margens de contato entre as colônias em ambiente natural e avaliação experimental da taxa de crescimento, através da remoção de uma área de

  13. Tidal Pumping-Induced Nutrients Dynamics and Biogeochemical Implications in an Intertidal Aquifer

    Science.gov (United States)

    Liu, Yi; Jiao, Jiu Jimmy; Liang, Wenzhao; Luo, Xin

    2017-12-01

    Tidal pumping is a major driving force affecting water exchange between land and sea, biogeochemical reactions in the intertidal aquifer, and nutrient loading to the sea. At a sandy beach of Tolo Harbour, Hong Kong, the nutrient (NH4+, NO2-, NO3-, and PO43-) dynamic in coastal groundwater mixing zone (CGMZ) is found to be fluctuated with tidal oscillation. Nutrient dynamic is mainly controlled by tidal pumping-induced organic matter that serves as a reagent of remineralization in the aquifer. NH4+, NO2-, and PO43- are positively correlated with salinity. Both NH4+ and PO43- have negative correlations with oxidation/reduction potential. NH4+ is the major dissolved inorganic nitrogen species in CGMZ. The adsorption of PO43- onto iron oxides occurs at the deep transition zone with a salinity of 5-10 practical salinity unit (psu), and intensive N-loss occurs in near-surface area with a salinity of 10-25 psu. The biogeochemical reactions, producing PO43- and consuming NH4+, are synergistic effect of remineralization-nitrification-denitrification. In CGMZ, the annual NH4+ loss is estimated to be 4.32 × 105 mol, while the minimum annual PO43- production is estimated to be 2.55 × 104 mol. Applying these rates to the entire Tolo Harbour, the annual NH4+ input to the harbor through the remineralization of organic matters is estimated to be 1.02 × 107 mol. The annual NH4+ loss via nitrification is 1.32 × 107 mol, and the annual PO43- production is 7.76 × 105 mol.

  14. Habitat use by Atherinella brasiliensis (Quoy & Gaimard, 1825 in intertidal zones of a subtropical estuary, Brazil

    Directory of Open Access Journals (Sweden)

    Barbara Maichak De Carvalho

    2015-11-01

    Full Text Available Habitat use is different along the ontogenetic development of some species and may be influenced by environmental parameters. This study described the interaction of Atherinella brasiliensis caught in intertidal areas of the Paranaguá Estuarine Complex with environmental parameters (salinity, chlorophyll, pH and water temperature. Collections were conducted between August 2010 and July 2011, at 17 sites in the north-south axis of the Paranaguá Estuarine Complex, Brazil. CTD profiling was carried out every month to measure the environmental parameters. At each month and sampling site, a paralel trawling 30 m long was carried out using a beach seine net 5 m long, 2 m high and 2.5 mm between opposite knots. After collection, fish were identified, measured for total length, weighed and the ages were estimated according von Bertalanffy. We caught 10024 individuals with total mean length of 44.32 mm (SD ± 25.37 mm, variation range between 12 and 142 mm, and weight between 0.01 and 73 g, averaging 1.35 g (SD ± 2.66 g and ages estimated between < 1 and 22 months. Significant differences were detected between sectors and periods for number of individuals and weight at capture, with higher mean values in the mean sector during the rainy period. The spatial and temporal distribution of ages was statistically different, individuals between < 1 and 3 months were more abundant in the sector 2 during the rainy period, and individuals older than 7 months were evenly distributed throughout the sampling area, and with higher mean abundance at the beginning and end of the dry period. Our results evidenced that all age classes of A. brasiliensis are present in shallow areas. This species shows different habitat use between age classes, which is caused by changes in feeding habits and higher availability of favorable environments, besides specific characteristics.

  15. DNA barcode assessment of Ceramiales (Rhodophyta) in the intertidal zone of the northwestern Yellow Sea

    Science.gov (United States)

    Du, Guoying; Wu, Feifei; Guo, Hao; Xue, Hongfan; Mao, Yunxiang

    2015-05-01

    A total of 142 specimens of Ceramiales (Rhodophyta) were collected each month from October 2011 to November 2012 in the intertidal zone of the northwestern Yellow Sea. These specimens covered 21 species, 14 genera, and four families. Cluster analyses show that the specimens had a high diversity for the three DNA markers, namely, partial large subunit rRNA gene (LSU), universal plastid amplicon (UPA), and partial mitochondrial cytochrome c oxidase subunit I gene (COI). No intraspecific divergence was found in our collection for these markers, except for a 1-3 bp divergence in the COI of Ceramium kondoi, Symphyocladia latiuscula, and Neosiphonia japonica. Because short DNA markers were used, the phylogenetic relationships of higher taxonomic levels were hard to evaluate with poor branch support. More than half species of our collection failed to find their matched sequences owing to shortage information of DNA barcodes for macroalgae in GenBank or BOLD (Barcode of Life Data) Systems. Three specimens were presumed as Heterosiphonia crispella by cluster analyses on DNA barcodes assisted by morphological identification, which was the first record in the investigated area, implying that it might be a cryptic or invasive species in the coastal area of northwestern Yellow Sea. In the neighbor-joining trees of all three DNA markers, Heterosiphonia japonica converged with Dasya spp. and was distant from the other Heterosiphonia spp., implying that H. japonica had affinities to the genus Dasya. The LSU and UPA markers amplified and sequenced easier than the COI marker across the Ceramiales species, but the COI had a higher ability to discriminate between species.

  16. Burrowing behavior of a deposit feeding bivalve predicts change in intertidal ecosystem state

    Directory of Open Access Journals (Sweden)

    Tanya Joan Compton

    2016-03-01

    Full Text Available Behavior has a predictive power that is often underutilized as a tool for signaling ecological change. The burrowing behavior of the deposit feeding bivalve Macoma balthica reflects a typical food-safety trade-off. The choice to live close to the sediment surface comes at a risk of predation and is a decision made when predation danger, food intake rates or future fitness prospects are low. In parts of the Dutch Wadden Sea, Macoma populations declined by 90% in the late 1990s, in parallel with large-scale mechanical cockle-dredging activities. During this decline, the burrowing depth of Macoma became shallow and was correlated with the population decline in the following year, indicating that it forecasted population change. Recently, there has been a series of large recruitment events in Macoma. According to the food-safety trade-off, we expected that Macoma should now live deeper, and have a higher body condition in association with this change in depth of living. Indeed, we observed that Macoma now lives deeper and that living depth in a given year forecasted population growth to the next year, especially in individuals larger than 14 mm. As living depth and body condition were strongly correlated in individuals larger than 14 mm, larger Macoma could be living deeper to protect their reproductive assets. Our results confirmed that burrowing depth signals impending population change and, together with body condition, can provide an early warning signal of ecological change. We suggest that population recovery is being driven by improved intertidal habitat quality in the Dutch Wadden Sea, rather than by the proposed climate-change related effects. This shift in ecosystem state is suggested to include the recovery of diatom habitat in the top layer of the sediment after cockle-dredging ended.

  17. Constancy despite variability: Local and regional macrofaunal diversity in intertidal seagrass beds

    Science.gov (United States)

    Boyé, Aurélien; Legendre, Pierre; Grall, Jacques; Gauthier, Olivier

    2017-12-01

    The importance of seagrass habitat for the diversity of benthic fauna has been extensively studied worldwide. Most of the information available is, however, about α diversity while little consideration has been given to β diversity. To fill the knowledge gaps regarding the variability of epifaunal and infaunal seagrass assemblages at large spatial and temporal scales, we scrutinized an extensive dataset covering five years of monitoring of eight intertidal Zostera marina meadows around Brittany (France). High species richness arose at the regional scale from the combination of high local diversity of the meadows and substantial among-meadows β diversity. Epifauna and infauna appeared as distinct self-communities as they displayed different spatial and temporal patterns and varied in their responses to local hydrological conditions. Infauna had higher total β diversity than epifauna due to a tighter link to the great variability of local environmental conditions in the region. Both exhibited substantial variations in species composition and community structure with variations of dominant species that were accompanied by extensive change in numerous rare species. The dominant epifaunal species were all grazers. Changes in species composition were induced mostly by species replacement and rarely by richness differences between meadows. Indeed, species richness remained within a narrow range for all seagrass beds, suggesting a potential carrying capacity for species richness of the meadows. Overall, all meadows contributed equally to the regional turnover of seagrass macrofauna, emphasizing high variability and complementarity among beds at the regional scale. The implications of this substantial within-seagrass variability for the functioning of benthic ecosystems at broad scale and for conservation purposes in habitat mosaics warrant further investigations but our results clearly advocate taking into account within-habitat variation when evaluating the diversity

  18. Dynamics of inorganic nutrients in intertidal sediments: porewater, exchangeable and intracellular pools

    Directory of Open Access Journals (Sweden)

    Emilio eGarcia-Robledo

    2016-05-01

    Full Text Available The study of inorganic nutrients dynamics in shallow sediments usually focuses on two main pools: the porewater (PW nutrients and the exchangeable (EX ammonium and phosphate. Recently, it has been found that microphytobenthos (MPB and other microorganisms can accumulate large amounts of nutrients intracellularly (IC, highlighting the biogeochemical importance of this nutrient pool. Storing nutrients could support the growth of autotrophs when nutrients are not available, and could also provide alternative electron acceptors for dissimilatory processes such as nitrate reduction. Here, we studied the magnitude and relative importance of these three nutrient pools (PW, IC and EX and their relation to chlorophylls (used as a proxy for MPB abundance and organic matter (OM contents in an intertidal mudflat of Cadiz Bay (Spain. MPB was localized in the first 4 mm of the sediment and showed a clear seasonal pattern; highest chlorophylls content was found during autumn and lowest during spring-summer. The temporal and spatial distribution of nutrients pools and MPB were largely correlated. Ammonium was higher in the IC and EX fractions, representing on average 59 and 37% of the total ammonium pool, respectively. Similarly, phosphate in the IC and EX fractions accounted on average for 40 and 31% of the total phosphate pool, respectively. Nitrate in the PW was low, suggesting low nitrification activity and rapid consumption. Nitrate accumulated in the IC pool during periods of moderate MPB abundance, being up to 66% of the total nitrate pool, whereas it decreased when chlorophyll concentration peaked likely due to a high nitrogen demand. EX-Nitrate accounted for the largest fraction of total sediment nitrate, 66% on average. The distribution of EX-Nitrate was significantly correlated with chlorophyll and OM, which probably indicates a relation of this pool to an increased availability of sites for ionic adsorption. This EX-Nitrate pool could represent an

  19. Variability in the fractionation of stable isotopes during degradation of two intertidal red algae

    Science.gov (United States)

    Hill, Jaclyn M.; McQuaid, Christopher D.

    2009-04-01

    Macroalgae contribute to intertidal food webs primarily as detritus, with unclear implications for food web studies using stable isotope analysis. We examined differences in the thallus parts of two South African rhodophytes ( Gelidium pristoides and Hypnea spicifera) and changes in overall δ13C, δ15N signatures and C:N ratios during degradation in both the field and laboratory. We hypothesized that both degrading macroalgal tissue and macroalgal-derived suspended particulate material (SPM) would show negligible changes in δ13C, but enriched δ15N signatures and lower C:N ratios relative to healthy plants. Only C:N laboratory ratios conformed to predictions, with both species of macroalgae showing decomposition related changes in δ13C and significant depletions in δ15N in both the field and laboratory. In the laboratory, algal tissue and SPM from each species behaved similarly (though some effects were non-significant) but with differing strengths. Gelidium pristoides δ13C increased and C:N ratios decreased over time in tissue and SPM; δ15N became depleted only in SPM. Hypnea spicifera, δ13C, δ15N and C:N ratios all decreased during degradation in both SPM and algae. Over 60 days in the field, δ13C was depleted in both species (1-2‰) and in naturally senescent Gelidium pristoides fronds. δ15N was depleted in Hypnea spicifera (approx. 1‰), while C:N ratios of both species were unaffected. The two species differed in δ13C, δ15N and C:N after degradation, but only in C:N beforehand. We suggest isotope changes in the laboratory mainly reflect microbial effects, while in the field these are combined with leaching due to constant water replenishment and agitation. Differences between these two species in the isotope responses to degradation highlight the difficulty of linking the signature of SPM to its multiple sources.

  20. Effects of shoreline treatment methods on intertidal biota in Prince William Sound

    International Nuclear Information System (INIS)

    Lees, D.C.; Houghton, J.P.; Driskell, W.B.

    1993-01-01

    Several studies conducted in Prince William Sound during 1989 were directed at assessing short term biological effects of treatment methods considered or employed for treating oil contaminated beaches. The four treatment alternatives evaluated in this paper are: low pressure warm water wash (LP-WW); high pressure hot water wash (HP-HW); the dispersant Corexit 7664; and the beach cleaner Corexit 9580 M2. Effects on the biota were assessed primarily on the basis of changes in the abundance of dominant taxa and the magnitude of selected community attributes (such as percent cover by algae or animals, and number of taxa). Significant reductions in one or more community or population attributes, and increases in the percent of dead mussels were observed in response to all types of treatment but the strongest and most consistent effects were observed following high pressure hot water treatment, which was also accompanied by heavy mortality in rockweed. Generally, the programs were not designed to discriminate among the potential causes of damage. However, available data suggest that neither chemical nor LP-WW treatments caused significant thermal impacts in the intertidal biota. In contrast, temperature appeared to cause significant mortality in the dominant plants and grazing and filter-feeding animals in HP-HW treatment sites. Observations of displacement and mortality for clams and mussels suggest that physical effects may be substantial in some cases. Of the types of treatment examined, dispersant and beach cleaner treatments appeared to be accompanied with the smallest number of significant changes in abundance; however, this conclusion is weak because the LP-WW wash accompanying chemical applications during the tests was sometimes less rigorous than when performed by itself. LP-WW treatment was accompanied by an intermediate level of changes whereas HP-HW treatment was accompanied with the highest percentage of changes, nearly all of which were decreases