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Sample records for tropical intertidal hermit

  1. Shell use and partitioning of two sympatric species of hermit crabs on a tropical mudflat

    Science.gov (United States)

    Teoh, Hong Wooi; Chong, Ving Ching

    2014-02-01

    Shell use and partitioning of two sympatric hermit crab species (Diogenes moosai and Diogenes lopochir), as determined by shell shape, size and availability, were examined from August 2009 to March 2011 in a tropical mudflat (Malaysia). Shells of 14 gastropod species were used but > 85% comprised shells of Cerithidea cingulata, Nassarius cf. olivaceus, Nassarius jacksonianus, and Thais malayensis. Shell partitioning between hermit crab species, sexes, and developmental stages was evident from occupied shells of different species, shapes, and sizes. Extreme bias in shell use pattern by male and female of both species of hermit crabs suggests that shell shape, which depends on shell species, is the major determinant of shell use. The hermit crab must however fit well into the shell so that compatibility between crab size and shell size becomes crucial. Although shell availability possibly influenced shell use and hermit crab distribution, this is not critical in a tropical setting of high gastropod diversity and abundance.

  2. Invasive ants compete with and modify the trophic ecology of hermit crabs on tropical islands.

    Science.gov (United States)

    McNatty, Alice; Abbott, Kirsti L; Lester, Philip J

    2009-05-01

    Invasive species can dramatically alter trophic interactions. Predation is the predominant trophic interaction generally considered to be responsible for ecological change after invasion. In contrast, how frequently competition from invasive species contributes to the decline of native species remains controversial. Here, we demonstrate how the trophic ecology of the remote atoll nation of Tokelau is changing due to competition between invasive ants (Anoplolepis gracilipes) and native terrestrial hermit crabs (Coenobita spp.) for carrion. A significant negative correlation was observed between A. gracilipes and hermit crab abundance. On islands with A. gracilipes, crabs were generally restricted to the periphery of invaded islands. Very few hermit crabs were found in central areas of these islands where A. gracilipes abundances were highest. Ant exclusion experiments demonstrated that changes in the abundance and distribution of hermit crabs on Tokelau are a result of competition. The ants did not kill the hermit crabs. Rather, when highly abundant, A. gracilipes attacked crabs by spraying acid and drove crabs away from carrion resources. Analysis of naturally occurring N and C isotopes suggests that the ants are effectively lowering the trophic level of crabs. According to delta(15) N values, hermit crabs have a relatively high trophic level on islands where A. gracilipes have not invaded. In contrast, where these ants have invaded we observed a significant decrease in delta(15) N for all crab species. This result concurs with our experiment in suggesting long-term exclusion from carrion resources, driving co-occurring crabs towards a more herbivorous diet. Changes in hermit crab abundance or distribution may have major ramifications for the stability of plant communities. Because A. gracilipes have invaded many tropical islands where the predominant scavengers are hermit crabs, we consider that their competitive effects are likely to be more prominent in

  3. 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

  4. 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.

  5. 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.

  6. The tropical African hermit crab Pagurus mbizi (Crustacea, Decapoda, Paguridae in the Western Mediterranean Sea: a new alien species or filling gaps in the knowledge of the distribution?

    Directory of Open Access Journals (Sweden)

    J. E. GARCIA RASO

    2013-12-01

    Full Text Available We report the first occurrence in the European Mediterranean Sea of a tropical Atlantic hermit crab, Pagurus mbizi (Forest, 1955, based on the capture of twenty specimens (all sizes and ovigerous females collected along the northern shores of the Alboran Sea, which proof the existence of a well-established population of this species, and the importance of this geographic area as a transitional and settlement zone for Atlantic species, which makes the Alboran Sea one of the richest marine biodiversity areas in the Mediterranean Sea. Some morphological comparative data with the closely related hermit crab Pagurus pubescentulus are given. In addition, data on its habitat and geographical distribution, as well as the probable pathways of introduction, are commented.

  7. 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.

  8. 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

  9. 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...

  10. 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...

  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. 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.

  13. Hermiticity and gauge invariance

    International Nuclear Information System (INIS)

    Treder, H.J.

    1987-01-01

    In the Theory of Hermitian Relativity (HRT) the postulates of hermiticity and gauge invariance are formulated in different ways, due to a different understanding of the idea of hermiticity. However all hermitian systems of equations have to satisfy Einstein's weak system of equations being equivalent to Einstein-Schroedinger equations. (author)

  14. 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

  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. 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...

  17. 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...

  18. Steerability of Hermite Kernel

    Czech Academy of Sciences Publication Activity Database

    Yang, Bo; Flusser, Jan; Suk, Tomáš

    2013-01-01

    Roč. 27, č. 4 (2013), 1354006-1-1354006-25 ISSN 0218-0014 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : Hermite polynomials * Hermite kernel * steerability * adaptive filtering Subject RIV: JD - Computer Applications, Robotics Impact factor: 0.558, year: 2013 http://library.utia.cas.cz/separaty/2013/ZOI/yang-0394387. pdf

  19. Fourier-Hermite communications; where Fourier meets Hermite

    NARCIS (Netherlands)

    Korevaar, C.W.; Kokkeler, Andre B.J.; de Boer, Pieter-Tjerk; Smit, Gerardus Johannes Maria

    A new signal set, based on the Fourier and Hermite signal bases, is introduced. It combines properties of the Fourier basis signals with the perfect time-frequency localization of the Hermite functions. The signal set is characterized by both a high spectral efficiency and good time-frequency

  20. Concentric layered Hermite scatterers

    Science.gov (United States)

    Astheimer, Jeffrey P.; Parker, Kevin J.

    2018-05-01

    The long wavelength limit of scattering from spheres has a rich history in optics, electromagnetics, and acoustics. Recently it was shown that a common integral kernel pertains to formulations of weak spherical scatterers in both acoustics and electromagnetic regimes. Furthermore, the relationship between backscattered amplitude and wavenumber k was shown to follow power laws higher than the Rayleigh scattering k2 power law, when the inhomogeneity had a material composition that conformed to a Gaussian weighted Hermite polynomial. Although this class of scatterers, called Hermite scatterers, are plausible, it may be simpler to manufacture scatterers with a core surrounded by one or more layers. In this case the inhomogeneous material property conforms to a piecewise continuous constant function. We demonstrate that the necessary and sufficient conditions for supra-Rayleigh scattering power laws in this case can be stated simply by considering moments of the inhomogeneous function and its spatial transform. This development opens an additional path for construction of, and use of scatterers with unique power law behavior.

  1. Hermit Thrush (Catharus guttatus)

    Science.gov (United States)

    Wood, Petra; Donovan, Therese M.

    2012-01-01

    With spotted breast and reddish tail, the Hermit Thrush lives up to its name. Although celebrated for its ethereal song, it is mostly a quiet and unobtrusive bird that spends much of its time in the lower branches of the undergrowth or on the forest floor, often seen flicking its wings while perched and quickly raising and slowly lowering its tail. A highly variable species in color and size, the Hermit Thrush's morphological characteristics and plumage have been well studied, with 12-13 subspecies now recognized (see Systematics).This thrush is one of the most widely distributed forest-nesting migratory birds in North America and the only forest thrush whose population has increased or remained stable over the past 20 years. Its extensive breeding range includes the northern hardwood forest, as well as most of the boreal and mountainous coniferous forest areas north of Mexico, with relatively recent expansions into New England and the southern Appalachians. In migration, the species moves to lower elevations and southward, spreading out to winter over much of the southern United States, through Mexico to Guatemala and east to Bermuda. It is the only species of Catharus that winters in North America, switching from a breeding diet of mainly arthropods to a wintering diet heavily supplemented with fruits.Much has been learned about this widely distributed species since the original Birds of North America account of 1996. New information pertaining to its song, migratory behavior, winter territoriality, survival, and diet has been added, as well as many new insights into the potential effects of forest management and other human disturbances. Still lacking are detailed nesting studies, studies of juvenile dispersal, of daily activities and time budgets, and of migratory routes.

  2. The Hermite transform-applications

    NARCIS (Netherlands)

    Martens, J.B.

    It is demonstrated how the Hermite transform can be used for image coding and analysis. Hierarchical coding structures based on increasingly specified basic patterns, i.e. general 2-D patterns, general 1-D patterns, and specific 1-D patterns such as edges and corners, are presented. In the image

  3. On the Equisummability of Hermite and Fourier Expansions

    Indian Academy of Sciences (India)

    We prove an equisummability result for the Fourier expansions and Hermite expansions as well as special Hermite expansions. We also prove the uniform boundedness of the Bochner-Riesz means associated to the Hermite expansions for polyradial functions.

  4. Seasonal changes in environmental variables, biomass, production and nutrient contents in two contrasting tropical intertidal seagrass beds in South Sulawesi, Indonesia.

    Science.gov (United States)

    Erftemeijer, Paul L A; Herman, Peter M J

    1994-09-01

    Seasonal dynamics were studied by monthly monitoring of biological and environmental variables in permanent quadrats in two contrasting intertidal seagrass beds in South Sulawesi, Indonesia, from February 1991 to January 1992. Datasets were analysed with canonical correlation analysis for correlations between environmental and biological variables. Considerable variation in biomass, production and plant tissue nutrient contents in a monospecific seagrass bed of Enhalus acoroides, growing on a coastal terrigenous mudbank (Gusung Tallang), was assumed to be related to riverine influences of the nearby Tallo River. The variation in seagrass variables at this site could, however, not be significantly correlated to seasonal patterns in rainfall, salinity, tides, nutrient availability, water motion or turbidity. A seasonal cycle in biomass, production and nutrient contents in a mixed seagrass bed of Thalassia hemprichii and E. acoroides, growing on carbonate sand on the reef flat of an offshore coral island (Barang Lompo), was found to be largely determined by tidal exposure and water motion. Exposure of the intertidal seagrass bed during hours of low water during spring tides showed a gradual shift from exposure during the night (January-June) to exposure during daylight (July-December). Daylight exposure resulted in a significant loss of above-ground plant biomass through desiccation and 'burning' of leaves. The observed seasonal dynamics of the seagrass bed on reef sediment contrast with reports from the Caribbean, where the effect of tidal exposure on comparable shallow-water seagrass communities is relatively insignificant due to a small tidal amplitude.

  5. 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

  6. Hermiticity of quantum observables versus commutation relations

    International Nuclear Information System (INIS)

    Shirokov, M.I.

    2002-01-01

    In order to obtain sum rules and spectral representations the Hermiticity property = of observables is used. It is shown that for certain Ψ and Φ the property turn out to be inconsistent with the commutation relations that contain Α. The known Schwinger paradox is explained by this inconsistency

  7. Differential operators associated with Hermite polynomials

    International Nuclear Information System (INIS)

    Onyango Otieno, V.P.

    1989-09-01

    This paper considers the boundary value problems for the Hermite differential equation -(e -x2 y'(x))'+e -x2 y(x)=λe -x2 y(x), (x is an element of (-∞, ∞)) in both the so-called right-definite and left-definite cases based partly on a classical approach due to E.C. Titchmarsh. We then link the Titchmarsh approach with operator theoretic results in the spaces L w 2 (-∞, ∞) and H p,q 2 (-∞, ∞). The results in the left-definite case provide an indirect proof of the completeness of the Hermite polynomials in L w 2 (-∞, ∞). (author). 17 refs

  8. Hermite scatterers in an ultraviolet sky

    Science.gov (United States)

    Parker, Kevin J.

    2017-12-01

    The scattering from spherical inhomogeneities has been a major historical topic in acoustics, optics, and electromagnetics and the phenomenon shapes our perception of the world including the blue sky. The long wavelength limit of ;Rayleigh scattering; is characterized by intensity proportional to k4 (or λ-4) where k is the wavenumber and λ is the wavelength. With the advance of nanotechnology, it is possible to produce scatterers that are inhomogeneous with material properties that are functions of radius r, such as concentric shells. We demonstrate that with proper choice of material properties linked to the Hermite polynomials in r, scatterers can have long wavelength scattering behavior of higher powers: k8, k16, and higher. These ;Hermite scatterers; could be useful in providing unique signatures (or colors) to regions where they are present. If suspended in air under white light, the back-scattered spectrum would be shifted from blue towards violet and then ultraviolet as the higher order Hermite scatterers were illuminated.

  9. Discrete Hermite moments and their application in chemometrics

    Czech Academy of Sciences Publication Activity Database

    Honarvar Shakibaei Asli, Barmak; Flusser, Jan

    2018-01-01

    Roč. 177, č. 1 (2018), s. 83-88 ISSN 0169-7439 Institutional support: RVO:67985556 Keywords : Orthogonal polynomials * Discrete polynomials * Tchebichef moment * Hermite moment * Gauss–Hermite quadrature Subject RIV: IN - Informatics, Computer Science OBOR OECD: Electrical and electronic engineering Impact factor: 2.303, year: 2016 http://library.utia.cas.cz/separaty/2018/ZOI/honarvar-0489186.pdf

  10. Hermiticity and CPT in string theory

    International Nuclear Information System (INIS)

    Sonoda, Hidenori

    1989-01-01

    In the application of conformal field theory to string theory S-matrix elements are obtained from correlation functions of vertex operators. By studying the relation between the vertex operators for the incoming states and those for the outgoing states we obtain two results: First we show that hermiticity of the string vertices is equivalent to the CPT invariance of the corresponding conformal field theory. Secondly we prove that the S-matrix elements in any string theory in flat space-time background are invariant under CPT. (orig.)

  11. Hermite y la trascendencia de e

    Directory of Open Access Journals (Sweden)

    José Manuel Sánchez Muñoz

    2011-04-01

    Full Text Available Este artículo es en parte una traducción de los trabajos que llevó a cabo el francés Charles Hermite para determinar la trascendencia del número e, considerado éste como base de los logaritmos neperianos. Se han realizado algunas simplificaciones en dicha demostración para hacerlamás asequible al lector. Se presenta además una introducción del número e a través de quien inventó su notación, Leonhard Euler.

  12. Scale invariants from Gaussian-Hermite moments

    Czech Academy of Sciences Publication Activity Database

    Yang, B.; Kostková, Jitka; Flusser, Jan; Suk, Tomáš

    2017-01-01

    Roč. 132, č. 1 (2017), s. 77-84 ISSN 0165-1684 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : Scale invariants * Gaussian–Hermite moments * Variable modulation * Normalization * Zernike moments Subject RIV: JD - Computer Applications, Robotics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 3.110, year: 2016 http://library.utia.cas.cz/separaty/2016/ZOI/flusser-0466031.pdf

  13. 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.

  14. 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.

  15. Fractional Delayer Utilizing Hermite Interpolation with Caratheodory Representation

    Directory of Open Access Journals (Sweden)

    Qiang DU

    2018-04-01

    Full Text Available Fractional delay is indispensable for many sorts of circuits and signal processing applications. Fractional delay filter (FDF utilizing Hermite interpolation with an analog differentiator is a straightforward way to delay discrete signals. This method has a low time-domain error, but a complicated sampling module than the Shannon sampling scheme. A simplified scheme, which is based on Shannon sampling and utilizing Hermite interpolation with a digital differentiator, will lead a much higher time-domain error when the signal frequency approaches the Nyquist rate. In this letter, we propose a novel fractional delayer utilizing Hermite interpolation with Caratheodory representation. The samples of differential signal are obtained by Caratheodory representation from the samples of the original signal only. So, only one sampler is needed and the sampling module is simple. Simulation results for four types of signals demonstrate that the proposed method has significantly higher interpolation accuracy than Hermite interpolation with digital differentiator.

  16. 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.

  17. Axisymmetric MHD equilibrium solver with bicubic Hermite elements

    International Nuclear Information System (INIS)

    Luetjens, H.; Bondeson, A.; Roy, A.

    1990-05-01

    A numerical code solving axisymmetric magnetohydrodynamic equilibria with rectangular bicubic Hermite elements has been developed. Two test cases are used for checking the convergence rate of the solution. The mapping of the equilibrium quantities into flux coordinates for magnetohydrodynamic stability calculation is performed by a method which preserves the convergence properties of the cubic Hermite elements. Convergence studies show the behaviour of the stability results when the equilibrium mesh is varied. (author) 13 refs., 3 tabs

  18. Evolution of king crabs from hermit crab ancestors

    Science.gov (United States)

    Cunningham, C. W.; Blackstone, N. W.; Buss, L. W.

    1992-02-01

    KING crabs (Family Lithodidae) are among the world's largest arthropods, having a crab-like morphology and a strongly calcified exoskeleton1-6. The hermit crabs, by contrast, have depended on gastropod shells for protection for over 150 million years5,7. Shell-living has constrained the morphological evolution of hermit crabs by requiring a decalcified asymmetrical abdomen capable of coiling into gastropod shells and by preventing crabs from growing past the size of the largest available shells1-6. Whereas reduction in shell-living and acquisition of a crab-like morphology (carcinization) has taken place independently in several hermit crab lineages, and most dramatically in king crabs1-6, the rate at which this process has occurred was entirely unknown2,7. We present molecular evidence that king crabs are not only descended from hermit crabs, but are nested within the hermit crab genus Pagurus. We estimate that loss of the shell-living habit and the complete carcinization of king crabs has taken between 13 and 25 million years.

  19. Discrete Hermite moments and their application in chemometrics

    Czech Academy of Sciences Publication Activity Database

    Honarvar Shakibaei Asli, Barmak; Flusser, Jan

    2018-01-01

    Roč. 177, č. 1 (2018), s. 83-88 ISSN 0169-7439 R&D Projects: GA ČR GA18-07247S; GA ČR GJ18-26018Y Institutional support: RVO:67985556 Keywords : Orthogonal polynomials * Discrete polynomials * Tchebichef moment * Hermite moment * Gauss–Hermite quadrature Subject RIV: JD - Computer Applications, Robotics OBOR OECD: Automation and control systems Impact factor: 2.303, year: 2016 http://library.utia.cas.cz/separaty/2018/ZOI/honarvar-0489147.pdf

  20. On the equisummability of Hermite and Fourier expansions

    Indian Academy of Sciences (India)

    is the Fourier transform on Rn. Let ب ; 2 Nn be the n-dimensional Hermite functions which are eigenfunctions of the Hermite operator H ¼ ہء jxj. 2 with the eigenvalue. ً2j j nق where j j ¼ 1 ءءء n. Let Pk be the orthogonal projection of L 2ًRnق onto the kth eigenspace spanned by ب ; j j ¼ k. More precisely,. Pk fًxق ¼. X j j¼k. Z.

  1. Temperature and salinity tolerance of adult hermit crabs, Diogenes ...

    African Journals Online (AJOL)

    1987-11-04

    Nov 4, 1987 ... estuary may not limit the distribution of hermit crabs. Because of their broad tolerance they should be able to survive near the head of the estuary. However, this continuous exposure to low salinity may be intolerable during moult and limit normal growth and metamorphosis, so although there may not be a.

  2. Modulated Hermite series expansions and the time-bandwidth product

    NARCIS (Netherlands)

    Brinker, den A.C.; Sarroukh, B.E.

    2000-01-01

    The harmonically modulated Hermite series constitute an orthonormal basis in the Hilbert space of square-integrable functions. This basis comprises three free parameters, namely a translation, a modulation, and a scale factor. In practical situations, we are interested in series expansions that are

  3. Explicit formulae for the generalized Hermite polynomials in superspace

    International Nuclear Information System (INIS)

    Desrosiers, Patrick; Lapointe, Luc; Mathieu, Pierre

    2004-01-01

    We provide explicit formulae for the orthogonal eigenfunctions of the supersymmetric extension of the rational Calogero-Moser-Sutherland model with harmonic confinement, i.e., the generalized Hermite (or Hi-Jack) polynomials in superspace. The construction relies on the triangular action of the Hamiltonian on the supermonomial basis. This translates into determinantal expressions for the Hamiltonian's eigenfunctions

  4. 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

  5. On some Hermite series identities and their applications to Gabor analysis

    DEFF Research Database (Denmark)

    Lemvig, Jakob

    2016-01-01

    We prove some infinite series identities for the Hermite functions. From these identities we disprove the Gabor frame set conjecture for Hermite functions of order (Formula presented.) and (Formula presented.) for (Formula presented.). The results hold not only for Hermite functions, but for two ...... large classes of eigenfunctions of the Fourier transform associated with the eigenvalues (Formula presented.) and i, and the results indicate that the Gabor frame set of all such functions must have a rather complicated structure....

  6. Near infrared face recognition using Zernike moments and Hermite kernels

    Czech Academy of Sciences Publication Activity Database

    Farokhi, Sajad; Sheikh, U.U.; Flusser, Jan; Yang, Bo

    2015-01-01

    Roč. 316, č. 1 (2015), s. 234-245 ISSN 0020-0255 R&D Projects: GA ČR(CZ) GA13-29225S Keywords : face recognition * Zernike moments * Hermite kernel * Decision fusion * Near infrared Subject RIV: JD - Computer Applications, Robotics Impact factor: 3.364, year: 2015 http://library.utia.cas.cz/separaty/2015/ZOI/flusser-0444205.pdf

  7. Rotation invariants from Gaussian-Hermite moments of color images

    Czech Academy of Sciences Publication Activity Database

    Yang, B.; Suk, Tomáš; Flusser, Jan; Shi, Z.; Chen, X.

    2018-01-01

    Roč. 143, č. 1 (2018), s. 282-291 ISSN 0165-1684 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : Color images * Object recognition * Rotation invariants * Gaussian–Hermite moments * Joint invariants Subject RIV: JD - Computer Applications, Robotics Impact factor: 3.110, year: 2016 http://library.utia.cas.cz/separaty/2017/ZOI/suk-0479748.pdf

  8. 3D rotation invariants of Gaussian-Hermite moments

    Czech Academy of Sciences Publication Activity Database

    Yang, Bo; Flusser, Jan; Suk, Tomáš

    2015-01-01

    Roč. 54, č. 1 (2015), s. 18-26 ISSN 0167-8655 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : Rotation invariants * Orthogonal moments * Gaussian–Hermite moments * 3D moment invariants Subject RIV: IN - Informatics, Computer Science Impact factor: 1.586, year: 2015 http://library.utia.cas.cz/separaty/2014/ZOI/yang-0438325.pdf

  9. Zeros of Wronskians of Hermite polynomials and Young diagrams

    Science.gov (United States)

    Felder, G.; Hemery, A. D.; Veselov, A. P.

    2012-12-01

    For a certain class of partitions, a simple qualitative relation is observed between the shape of the Young diagram and the pattern of zeros of the Wronskian of the corresponding Hermite polynomials. In the case of the two-term Wronskian W(Hn,Hn+k), we give an explicit formula for the asymptotic shape of the zero set as n→∞. Some empirical asymptotic formulas are given for the zero sets of three-term and four-term Wronskians.

  10. Five Martyr Brothers. First Polish hermits and their worship

    Directory of Open Access Journals (Sweden)

    Kinga Blaschke

    2016-12-01

    Full Text Available Brothers Benedict and John, students of Romuald, came to Poland at the invitation of Otto III to convert pagans. Soon the Italian hermits were joined by Polish brothers Isaac and Matthew, who helped them in learning the Slavic language. The hermits, as well as Christinus, well killed in 1003 by thugs who wanted to steal money given by Duke Boleslav to an expedition to Rome, which was aimed at obtaining papal consent for conducting missionary work. Although the hermits died as victims of a robbery, killed by fellow Christians, the pope canonized them as martyrs. Their lives are relatively well-documented: the earliest and the most credible story of the five brothers by Bruno of Querfurt was written as early as five years after their death, although remained unknown until 1883. Another early account is the life of St. Romuald by Piotr Damiani of 1041. The martyrs have been also associated with yet another mysterious work – a gravestone unearthed in 1959 at the external wall of the north Roman apse of the Gniezno Cathedral, considered by most researchers the oldest epigraphic item on the Polish soil. However, the identification of the warriors mentioned in the inscription with 11th century martyrs raises many doubts. The article discusses the above matters, as well as the subject of the development of the worship of the martyr brothers.

  11. Hermite Polynomials and the Inverse Problem for Collisionless Equilibria

    Science.gov (United States)

    Allanson, O.; Neukirch, T.; Troscheit, S.; Wilson, F.

    2017-12-01

    It is long established that Hermite polynomial expansions in either velocity or momentum space can elegantly encode the non-Maxwellian velocity-space structure of a collisionless plasma distribution function (DF). In particular, Hermite polynomials in the canonical momenta naturally arise in the consideration of the 'inverse problem in collisionless equilibria' (IPCE): "for a given macroscopic/fluid equilibrium, what are the self-consistent Vlasov-Maxwell equilibrium DFs?". This question is of particular interest for the equilibrium and stability properties of a given macroscopic configuration, e.g. a current sheet. It can be relatively straightforward to construct a formal solution to IPCE by a Hermite expansion method, but several important questions remain regarding the use of this method. We present recent work that considers the necessary conditions of non-negativity, convergence, and the existence of all moments of an equilibrium DF solution found for IPCE. We also establish meaningful analogies between the equations that link the microscopic and macrosopic descriptions of the Vlasov-Maxwell equilibrium, and those that solve the initial value problem for the heat equation. In the language of the heat equation, IPCE poses the pressure tensor as the 'present' heat distribution over an infinite domain, and the non-Maxwellian features of the DF as the 'past' distribution. We find sufficient conditions for the convergence of the Hermite series representation of the DF, and prove that the non-negativity of the DF can be dependent on the magnetisation of the plasma. For DFs that decay at least as quickly as exp(-v^2/4), we show non-negativity is guaranteed for at least a finite range of magnetisation values, as parameterised by the ratio of the Larmor radius to the gradient length scale. 1. O. Allanson, T. Neukirch, S. Troscheit & F. Wilson: From one-dimensional fields to Vlasov equilibria: theory and application of Hermite polynomials, Journal of Plasma Physics, 82

  12. Fourier–Hermite spectral representation for the Vlasov–Poisson system in the weakly collisional limit

    KAUST Repository

    Parker, Joseph T.

    2015-02-03

    Copyright © Cambridge University Press 2015. We study Landau damping in the 1+1D Vlasov-Poisson system using a Fourier-Hermite spectral representation. We describe the propagation of free energy in Fourier-Hermite phase space using forwards and backwards propagating Hermite modes recently developed for gyrokinetic theory. We derive a free energy equation that relates the change in the electric field to the net Hermite flux out of the zeroth Hermite mode. In linear Landau damping, decay in the electric field corresponds to forward propagating Hermite modes; in nonlinear damping, the initial decay is followed by a growth phase characterized by the generation of backwards propagating Hermite modes by the nonlinear term. The free energy content of the backwards propagating modes increases exponentially until balancing that of the forward propagating modes. Thereafter there is no systematic net Hermite flux, so the electric field cannot decay and the nonlinearity effectively suppresses Landau damping. These simulations are performed using the fully-spectral 5D gyrokinetics code SpectroGK, modified to solve the 1+1D Vlasov-Poisson system. This captures Landau damping via Hou-Li filtering in velocity space. Therefore the code is applicable even in regimes where phase mixing and filamentation are dominant.

  13. Closed-form expressions for time-frequency operations involving Hermite functions

    NARCIS (Netherlands)

    Korevaar, C.W.; Oude Alink, M.S.; de Boer, Pieter-Tjerk; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2016-01-01

    The product, convolution, correlation, Wigner distribution function (WDF) and ambiguity function (AF) of two Hermite functions of arbitrary order n and m are derived and expressed as a bounded, weighted sum of n+m Hermite functions. It was already known that these mathematical operations performed

  14. Fourier–Hermite spectral representation for the Vlasov–Poisson system in the weakly collisional limit

    KAUST Repository

    Parker, Joseph T.; Dellar, Paul J.

    2015-01-01

    Copyright © Cambridge University Press 2015. We study Landau damping in the 1+1D Vlasov-Poisson system using a Fourier-Hermite spectral representation. We describe the propagation of free energy in Fourier-Hermite phase space using forwards

  15. Discrete linear canonical transforms based on dilated Hermite functions.

    Science.gov (United States)

    Pei, Soo-Chang; Lai, Yun-Chiu

    2011-08-01

    Linear canonical transform (LCT) is very useful and powerful in signal processing and optics. In this paper, discrete LCT (DLCT) is proposed to approximate LCT by utilizing the discrete dilated Hermite functions. The Wigner distribution function is also used to investigate DLCT performances in the time-frequency domain. Compared with the existing digital computation of LCT, our proposed DLCT possess additivity and reversibility properties with no oversampling involved. In addition, the length of input/output signals will not be changed before and after the DLCT transformations, which is consistent with the time-frequency area-preserving nature of LCT; meanwhile, the proposed DLCT has very good approximation of continuous LCT.

  16. Cardinal Basis Piecewise Hermite Interpolation on Fuzzy Data

    Directory of Open Access Journals (Sweden)

    H. Vosoughi

    2016-01-01

    Full Text Available A numerical method along with explicit construction to interpolation of fuzzy data through the extension principle results by widely used fuzzy-valued piecewise Hermite polynomial in general case based on the cardinal basis functions, which satisfy a vanishing property on the successive intervals, has been introduced here. We have provided a numerical method in full detail using the linear space notions for calculating the presented method. In order to illustrate the method in computational examples, we take recourse to three prime cases: linear, cubic, and quintic.

  17. Squeezing of higher order Hermite-Gauss modes

    DEFF Research Database (Denmark)

    Lassen, Mikael Østergaard

    2008-01-01

    The present paper gives an overview of the experimental generation of squeezing in higher order Hermite-Gaussian modes with an optical parametric ampli¯er (OPA). This work was awarded with The European Optical Society (EOS) price 2007. The purpose of the prize is to encourage a European dimension...... in research in pure and applied optics. The EOS prize is awarded based on the selection criteria of high professionalism, academic and technical quality. Following the EOS Prize rules, the conditions for eligibility are that the work was performed in Europe and that it is published under the auspices...

  18. Interstitial water chemistry and nutrients fluxes from tropical intertidal sediment

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.; Zingde, M.D.

    temporal changes in relation to their con- centrations in the overlying creek water. The high chlorinity creek water infiltrating in the bed after September, progres- sively pushed down the monsoonal low chlorinity water trapped in the sediment resulting....4-2.5%), the trend of decreasing con- centration with depth indicated some accumulation in the sediment over the years. The 1.0-2.5% Corgin core 2 commonly occurs in silty-clay sediment along the centra] west coast of India16 even in areas where there is no apparent...

  19. Squeezed states and Hermite polynomials in a complex variable

    International Nuclear Information System (INIS)

    Ali, S. Twareque; Górska, K.; Horzela, A.; Szafraniec, F. H.

    2014-01-01

    Following the lines of the recent paper of J.-P. Gazeau and F. H. Szafraniec [J. Phys. A: Math. Theor. 44, 495201 (2011)], we construct here three types of coherent states, related to the Hermite polynomials in a complex variable which are orthogonal with respect to a non-rotationally invariant measure. We investigate relations between these coherent states and obtain the relationship between them and the squeezed states of quantum optics. We also obtain a second realization of the canonical coherent states in the Bargmann space of analytic functions, in terms of a squeezed basis. All this is done in the flavor of the classical approach of V. Bargmann [Commun. Pure Appl. Math. 14, 187 (1961)

  20. Niche construction drives social dependence in hermit crabs.

    Science.gov (United States)

    Laidre, Mark E

    2012-10-23

    Organisms can receive not only a genetic inheritance from their ancestors but also an ecological inheritance, involving modifications their ancestors made to the environment through niche construction. Ecological inheritances may persist as a legacy, potentially generating selection pressures that favor sociality. Yet, most proposed cases of sociality being impacted by an ecological inheritance come from organisms that live among close kin and were highly social before their niche construction began. Here, I show that in terrestrial hermit crabs (Coenobita compressus)--organisms that do not live with kin and reside alone, each in its own shell--niche-construction drives social dependence, such that individuals can only survive in remodeled shells handed down from conspecifics. These results suggest that niche construction can be an important initiator of evolutionary pressures to socialize, even among unrelated and otherwise asocial organisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Complex and real Hermite polynomials and related quantizations

    International Nuclear Information System (INIS)

    Cotfas, Nicolae; Gazeau, Jean Pierre; Gorska, Katarzyna

    2010-01-01

    It is known that the anti-Wick (or standard coherent state) quantization of the complex plane produces both canonical commutation rule and quantum spectrum of the harmonic oscillator (up to the addition of a constant). In this work, we show that these two issues are not necessarily coupled: there exists a family of separable Hilbert spaces, including the usual Fock-Bargmann space, and in each element in this family there exists an overcomplete set of unit-norm states resolving the unity. With the exception of the Fock-Bargmann case, they all produce non-canonical commutation relation whereas the quantum spectrum of the harmonic oscillator remains the same up to the addition of a constant. The statistical aspects of these non-equivalent coherent state quantizations are investigated. We also explore the localization aspects in the real line yielded by similar quantizations based on real Hermite polynomials.

  2. Brain architecture in the terrestrial hermit crab Coenobita clypeatus (Anomura, Coenobitidae, a crustacean with a good aerial sense of smell

    Directory of Open Access Journals (Sweden)

    Hansson Bill S

    2008-06-01

    Full Text Available Abstract Background During the evolutionary radiation of Crustacea, several lineages in this taxon convergently succeeded in meeting the physiological challenges connected to establishing a fully terrestrial life style. These physiological adaptations include the need for sensory organs of terrestrial species to function in air rather than in water. Previous behavioral and neuroethological studies have provided solid evidence that the land hermit crabs (Coenobitidae, Anomura are a group of crustaceans that have evolved a good sense of aerial olfaction during the conquest of land. We wanted to study the central olfactory processing areas in the brains of these organisms and to that end analyzed the brain of Coenobita clypeatus (Herbst, 1791; Anomura, Coenobitidae, a fully terrestrial tropical hermit crab, by immunohistochemistry against synaptic proteins, serotonin, FMRFamide-related peptides, and glutamine synthetase. Results The primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that C. clypeatus has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusion In parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes, superficially similar to the lamellae in the secondary olfactory centers of C. clypeatus. More detailed analyses with

  3. Time-Frequency Analysis and Hermite Projection Method Applied to Swallowing Accelerometry Signals

    Directory of Open Access Journals (Sweden)

    Ervin Sejdić

    2010-01-01

    Full Text Available Fast Hermite projections have been often used in image-processing procedures such as image database retrieval, projection filtering, and texture analysis. In this paper, we propose an innovative approach for the analysis of one-dimensional biomedical signals that combines the Hermite projection method with time-frequency analysis. In particular, we propose a two-step approach to characterize vibrations of various origins in swallowing accelerometry signals. First, by using time-frequency analysis we obtain the energy distribution of signal frequency content in time. Second, by using fast Hermite projections we characterize whether the analyzed time-frequency regions are associated with swallowing or other phenomena (vocalization, noise, bursts, etc.. The numerical analysis of the proposed scheme clearly shows that by using a few Hermite functions, vibrations of various origins are distinguishable. These results will be the basis for further analysis of swallowing accelerometry to detect swallowing difficulties.

  4. On integral and finite Fourier transforms of continuous q-Hermite polynomials

    International Nuclear Information System (INIS)

    Atakishiyeva, M. K.; Atakishiyev, N. M.

    2009-01-01

    We give an overview of the remarkably simple transformation properties of the continuous q-Hermite polynomials H n (x vertical bar q) of Rogers with respect to the classical Fourier integral transform. The behavior of the q-Hermite polynomials under the finite Fourier transform and an explicit form of the q-extended eigenfunctions of the finite Fourier transform, defined in terms of these polynomials, are also discussed.

  5. 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

  6. 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

  7. 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

  8. 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

  9. Ongoing movement of the hermit warbler X Townsend's warbler hybrid zone.

    Directory of Open Access Journals (Sweden)

    Meade Krosby

    Full Text Available BACKGROUND: Movements of hybrid zones - areas of overlap and interbreeding between species - are difficult to document empirically. This is true because moving hybrid zones are expected to be rare, and because movement may proceed too slowly to be measured directly. Townsend's warblers (Dendroica townsendi hybridize with hermit warblers (D. occidentalis where their ranges overlap in Washington and Oregon. Previous morphological, behavioral, and genetic studies of this hybrid zone suggest that it has been steadily moving into the geographical range of hermit warblers, with the more aggressive Townsend's warblers replacing hermit warblers along ∼2000 km of the Pacific coast of Canada and Alaska. Ongoing movement of the zone, however, has yet to be empirically demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: We compared recently sampled hybrid zone specimens to those collected 10-20 years earlier, to test directly the long-standing hypothesis of hybrid zone movement between these species. Newly sampled specimens were more Townsend's-like than historical specimens, consistent with ongoing movement of the zone into the geographical range of hermit warblers. CONCLUSIONS/SIGNIFICANCE: While movement of a hybrid zone may be explained by several possible mechanisms, in this case a wealth of existing evidence suggests that movement is being driven by the competitive displacement of hermit warblers by Townsend's warblers. That no ecological differences have been found between these species, and that replacement of hermit warblers by Townsend's warblers is proceeding downward in latitude and elevation - opposite the directions of range shifts predicted by recent climate change - further support that this movement is not being driven by alternative environmental factors. If the mechanism of competitive displacement is correct, whether this process will ultimately lead to the extinction of hermit warblers will depend on the continued maintenance of the

  10. A GIS model predicting potential distributions of a lineage: a test case on hermit spiders (Nephilidae: Nephilengys).

    Science.gov (United States)

    Năpăruş, Magdalena; Kuntner, Matjaž

    2012-01-01

    Although numerous studies model species distributions, these models are almost exclusively on single species, while studies of evolutionary lineages are preferred as they by definition study closely related species with shared history and ecology. Hermit spiders, genus Nephilengys, represent an ecologically important but relatively species-poor lineage with a globally allopatric distribution. Here, we model Nephilengys global habitat suitability based on known localities and four ecological parameters. We geo-referenced 751 localities for the four most studied Nephilengys species: N. cruentata (Africa, New World), N. livida (Madagascar), N. malabarensis (S-SE Asia), and N. papuana (Australasia). For each locality we overlaid four ecological parameters: elevation, annual mean temperature, annual mean precipitation, and land cover. We used linear backward regression within ArcGIS to select two best fit parameters per species model, and ModelBuilder to map areas of high, moderate and low habitat suitability for each species within its directional distribution. For Nephilengys cruentata suitable habitats are mid elevation tropics within Africa (natural range), a large part of Brazil and the Guianas (area of synanthropic spread), and even North Africa, Mediterranean, and Arabia. Nephilengys livida is confined to its known range with suitable habitats being mid-elevation natural and cultivated lands. Nephilengys malabarensis, however, ranges across the Equator throughout Asia where the model predicts many areas of high ecological suitability in the wet tropics. Its directional distribution suggests the species may potentially spread eastwards to New Guinea where the suitable areas of N. malabarensis largely surpass those of the native N. papuana, a species that prefers dry forests of Australian (sub)tropics. Our model is a customizable GIS tool intended to predict current and future potential distributions of globally distributed terrestrial lineages. Its predictive

  11. Using harmonic oscillators to determine the spot size of Hermite-Gaussian laser beams

    Science.gov (United States)

    Steely, Sidney L.

    1993-01-01

    The similarity of the functional forms of quantum mechanical harmonic oscillators and the modes of Hermite-Gaussian laser beams is illustrated. This functional similarity provides a direct correlation to investigate the spot size of large-order mode Hermite-Gaussian laser beams. The classical limits of a corresponding two-dimensional harmonic oscillator provide a definition of the spot size of Hermite-Gaussian laser beams. The classical limits of the harmonic oscillator provide integration limits for the photon probability densities of the laser beam modes to determine the fraction of photons detected therein. Mathematica is used to integrate the probability densities for large-order beam modes and to illustrate the functional similarities. The probabilities of detecting photons within the classical limits of Hermite-Gaussian laser beams asymptotically approach unity in the limit of large-order modes, in agreement with the Correspondence Principle. The classical limits for large-order modes include all of the nodes for Hermite Gaussian laser beams; Sturm's theorem provides a direct proof.

  12. O(N) symmetries, sum rules for generalized Hermite polynomials and squeezed states

    International Nuclear Information System (INIS)

    Daboul, Jamil; Mizrahi, Salomon S

    2005-01-01

    Quantum optics has been dealing with coherent states, squeezed states and many other non-classical states. The associated mathematical framework makes use of special functions as Hermite polynomials, Laguerre polynomials and others. In this connection we here present some formal results that follow directly from the group O(N) of complex transformations. Motivated by the squeezed states structure, we introduce the generalized Hermite polynomials (GHP), which include as particular cases, the Hermite polynomials as well as the heat polynomials. Using generalized raising operators, we derive new sum rules for the GHP, which are covariant under O(N) transformations. The GHP and the associated sum rules become useful for evaluating Wigner functions in a straightforward manner. As a byproduct, we use one of these sum rules, on the operator level, to obtain raising and lowering operators for the Laguerre polynomials and show that they generate an sl(2, R) ≅ su(1, 1) algebra

  13. Efficient modeling of photonic crystals with local Hermite polynomials

    International Nuclear Information System (INIS)

    Boucher, C. R.; Li, Zehao; Albrecht, J. D.; Ram-Mohan, L. R.

    2014-01-01

    Developing compact algorithms for accurate electrodynamic calculations with minimal computational cost is an active area of research given the increasing complexity in the design of electromagnetic composite structures such as photonic crystals, metamaterials, optical interconnects, and on-chip routing. We show that electric and magnetic (EM) fields can be calculated using scalar Hermite interpolation polynomials as the numerical basis functions without having to invoke edge-based vector finite elements to suppress spurious solutions or to satisfy boundary conditions. This approach offers several fundamental advantages as evidenced through band structure solutions for periodic systems and through waveguide analysis. Compared with reciprocal space (plane wave expansion) methods for periodic systems, advantages are shown in computational costs, the ability to capture spatial complexity in the dielectric distributions, the demonstration of numerical convergence with scaling, and variational eigenfunctions free of numerical artifacts that arise from mixed-order real space basis sets or the inherent aberrations from transforming reciprocal space solutions of finite expansions. The photonic band structure of a simple crystal is used as a benchmark comparison and the ability to capture the effects of spatially complex dielectric distributions is treated using a complex pattern with highly irregular features that would stress spatial transform limits. This general method is applicable to a broad class of physical systems, e.g., to semiconducting lasers which require simultaneous modeling of transitions in quantum wells or dots together with EM cavity calculations, to modeling plasmonic structures in the presence of EM field emissions, and to on-chip propagation within monolithic integrated circuits

  14. Linear flow of heat in an infinite region and hermite polynomials

    International Nuclear Information System (INIS)

    Al-Hawaj, A.Y.

    1991-01-01

    The problem of linear flow of heat in an infinite region occupies a prominent place in the field of conduction of heat in solids. A number of solutions to this problem, have been given from time to time by several mathematicians. The object of this paper is to derive the solutions of the problem of linear flow of heat in an infinite region, which lead to Hermite Polynomials. The author further presents three linear combinations of his solutions and their particular cases. The region (- ∞ < x < ∞) of the problem led him to investigate the solutions of the problem in terms of Hermite Polynomials

  15. Do I stand out or blend in? Conspicuousness awareness and consistent behavioural differences in hermit crabs.

    Science.gov (United States)

    Briffa, Mark; Twyman, Claire

    2011-06-23

    Animals titrate their behaviour against the level of risk and an individual's conspicuousness should influence decisions such as when to flee and for how long to hide. Conspicuousness will vary with variation in substrate colour. Since hermit crabs frequently change the shells they occupy, shell colour will also influence conspicuousness and to be aware of their conspicuousness would require information on both of these factors to be integrated. Reduced boldness in high-contrast shell and substrate combinations compared with situations of low contrast indicates that hermit crabs are aware of current conspicuousness. Differences between individuals remained consistent across conspicuousness levels indicating the presence of animal personalities.

  16. 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

  17. 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

  18. 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...

  19. A GIS model predicting potential distributions of a lineage: a test case on hermit spiders (Nephilidae: Nephilengys.

    Directory of Open Access Journals (Sweden)

    Magdalena Năpăruş

    Full Text Available BACKGROUND: Although numerous studies model species distributions, these models are almost exclusively on single species, while studies of evolutionary lineages are preferred as they by definition study closely related species with shared history and ecology. Hermit spiders, genus Nephilengys, represent an ecologically important but relatively species-poor lineage with a globally allopatric distribution. Here, we model Nephilengys global habitat suitability based on known localities and four ecological parameters. METHODOLOGY/PRINCIPAL FINDINGS: We geo-referenced 751 localities for the four most studied Nephilengys species: N. cruentata (Africa, New World, N. livida (Madagascar, N. malabarensis (S-SE Asia, and N. papuana (Australasia. For each locality we overlaid four ecological parameters: elevation, annual mean temperature, annual mean precipitation, and land cover. We used linear backward regression within ArcGIS to select two best fit parameters per species model, and ModelBuilder to map areas of high, moderate and low habitat suitability for each species within its directional distribution. For Nephilengys cruentata suitable habitats are mid elevation tropics within Africa (natural range, a large part of Brazil and the Guianas (area of synanthropic spread, and even North Africa, Mediterranean, and Arabia. Nephilengys livida is confined to its known range with suitable habitats being mid-elevation natural and cultivated lands. Nephilengys malabarensis, however, ranges across the Equator throughout Asia where the model predicts many areas of high ecological suitability in the wet tropics. Its directional distribution suggests the species may potentially spread eastwards to New Guinea where the suitable areas of N. malabarensis largely surpass those of the native N. papuana, a species that prefers dry forests of Australian (subtropics. CONCLUSIONS: Our model is a customizable GIS tool intended to predict current and future potential

  20. Evolution of sexual dimorphism in bill size and shape of hermit hummingbirds (Phaethornithinae): a role for ecological causation.

    Science.gov (United States)

    Temeles, Ethan J; Miller, Jill S; Rifkin, Joanna L

    2010-04-12

    Unambiguous examples of ecological causation of sexual dimorphism are rare, and the best evidence involves sexual differences in trophic morphology. We show that moderate female-biased sexual dimorphism in bill curvature is the ancestral condition in hermit hummingbirds (Phaethornithinae), and that it is greatly amplified in species such as Glaucis hirsutus and Phaethornis guy, where bills of females are 60 per cent more curved than bills of males. In contrast, bill curvature dimorphism is lost or reduced in a lineage of short-billed hermit species and in specialist Eutoxeres sicklebill hermits. In the hermits, males tend to be larger than females in the majority of species, although size dimorphism is typically small. Consistent with earlier studies of hummingbird feeding performance, both raw regressions of traits and phylogenetic independent contrasts supported the prediction that dimorphism in bill curvature of hermits is associated with longer bills. Some evidence indicates that differences between sexes of hermit hummingbirds are associated with differences in the use of food plants. We suggest that some hermit hummingbirds provide model organisms for studies of ecological causation of sexual dimorphism because their sexual dimorphism in bill curvature provides a diagnostic clue for the food plants that need to be monitored for studies of sexual differences in resource use.

  1. Hermite-Hadamard type inequalities for GA-s-convex functions

    Directory of Open Access Journals (Sweden)

    İmdat İşcan

    2014-10-01

    Full Text Available In this paper, The author introduces the concepts of the GA-s-convex functions in the first sense and second sense and establishes some integral inequalities of Hermite-Hadamard type related to the GA-s-convex functions. Some applications to special means of real numbers are also given.

  2. Approximation by some combinations of Poisson integrals for Hermite and Laguerre expansions

    Directory of Open Access Journals (Sweden)

    Grażyna Krech

    2013-02-01

    Full Text Available The aim of this paper is the study of a rate of convergence of some combinations of Poisson integrals for Hermite and Laguerre expansions. We are able to achieve faster convergence for our modified operators over the Poisson integrals. We prove also the Voronovskaya type theorem for these new operators.

  3. Boundedness of the Segal-Bargmann Transform on Fractional Hermite-Sobolev Spaces

    Directory of Open Access Journals (Sweden)

    Hong Rae Cho

    2017-01-01

    Full Text Available Let s∈R and 2≤p≤∞. We prove that the Segal-Bargmann transform B is a bounded operator from fractional Hermite-Sobolev spaces WHs,pRn to fractional Fock-Sobolev spaces FRs,p.

  4. Jitter-Robust Orthogonal Hermite Pulses for Ultra-Wideband Impulse Radio Communications

    Directory of Open Access Journals (Sweden)

    Ryuji Kohno

    2005-03-01

    Full Text Available The design of a class of jitter-robust, Hermite polynomial-based, orthogonal pulses for ultra-wideband impulse radio (UWB-IR communications systems is presented. A unified and exact closed-form expression of the auto- and cross-correlation functions of Hermite pulses is provided. Under the assumption that jitter values are sufficiently smaller than pulse widths, this formula is used to decompose jitter-shifted pulses over an orthonormal basis of the Hermite space. For any given jitter probability density function (pdf, the decomposition yields an equivalent distribution of N-by-N matrices which simplifies the convolutional jitter channel model onto a multiplicative matrix model. The design of jitter-robust orthogonal pulses is then transformed into a generalized eigendecomposition problem whose solution is obtained with a Jacobi-like simultaneous diagonalization algorithm applied over a subset of samples of the channel matrix distribution. Examples of the waveforms obtained with the proposed design and their improved auto- and cross-correlation functions are given. Simulation results are presented, which demonstrate the superior performance of a pulse-shape modulated (PSM- UWB-IR system using the proposed pulses, over the same system using conventional orthogonal Hermite pulses, in jitter channels with additive white Gaussian noise (AWGN.

  5. The problem of electric sources in Einstein's Hermite-symmetric field theory

    International Nuclear Information System (INIS)

    Kreisel, E.

    1986-01-01

    The possibility is investigated to introduce a geometric source without A-invariance and Hermite-symmetry breaking of Einstein's Hermitian relativity. It would be very meaningful to interpret a source of this kind as electric current. With this extension Einstein's unitary field theory contains Einstein's gravitation, electromagnetism and the gluonic vacuum of chromodynamics. (author)

  6. Adaptive multiresolution Hermite-Binomial filters for image edge and texture analysis

    NARCIS (Netherlands)

    Gu, Y.H.; Katsaggelos, A.K.

    1994-01-01

    A new multiresolution image analysis approach using adaptive Hermite-Binomial filters is presented in this paper. According to the local image structural and textural properties, the analysis filter kernels are made adaptive both in their scales and orders. Applications of such an adaptive filtering

  7. 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.

  8. Pollination and breeding system of Canna paniculata(Cannaceae in a montane Atlantic Rainforest: asymmetric dependence on a hermit hummingbird

    Directory of Open Access Journals (Sweden)

    Pietro Kiyoshi Maruyama

    2015-03-01

    Full Text Available We studied the pollination biology of Canna paniculata (Cannaceae, a plant species common in the Atlantic Rainforest of southeastern Brazil. The species presents specialized ornithophilous flowers, which in our study area are solely pollinated by the hermit hummingbird Phaethornis eurynome. Although C. paniculata is capable of bearing fruit after self-pollination, it requires pollinators for reproduction. We discuss the importance of hermit hummingbirds for the reproduction of specialized ornithophilous plants such as C. paniculata, including their asymmetric dependence on hermit hummingbirds - core pollinators in Neotropical forest ecosystems.

  9. 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.

  10. 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.

  11. 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.

  12. Tropical Forest Fragmentation Limits Movements, but Not Occurrence of a Generalist Pollinator Species.

    Directory of Open Access Journals (Sweden)

    Noelia L Volpe

    Full Text Available Habitat loss and fragmentation influence species distributions and therefore ecological processes that depend upon them. Pollination may be particularly susceptible to fragmentation, as it depends on frequent pollinator movement. Unfortunately, most pollinators are too small to track efficiently which has precluded testing the hypothesis that habitat fragmentation reduces or eliminates pollen flow by disrupting pollinator movement. We used radio-telemetry to examine space use of the green hermit hummingbird (Phaethornis guy, an important 'hub' pollinator of understory flowering plants across substantial portions of the neotropics and the primary pollinator of a keystone plant which shows reduced pollination success in fragmented landscapes. We found that green hermits strongly avoided crossing large stretches of non-forested matrix and preferred to move along stream corridors. Forest gaps as small as 50 m diminished the odds of movement by 50%. Green hermits occurred almost exclusively inside the forest, with the odds of occurrence being 8 times higher at points with >95% canopy cover compared with points having <5% canopy cover. Nevertheless, surprisingly. the species occurred in fragmented landscapes with low amounts of forest (~30% within a 2 km radius. Our results indicate that although green hermits are present even in landscapes with low amounts of tropical forest, movement within these landscapes ends up strongly constrained by forest gaps. Restricted movement of pollinators may be an underappreciated mechanism for widespread declines in pollination and plant fitness in fragmented landscapes, even when in the presence of appropriate pollinators.

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. Solution of Stochastic Nonlinear PDEs Using Automated Wiener-Hermite Expansion

    KAUST Repository

    Al-Juhani, Amnah

    2014-01-06

    The solution of the stochastic differential equations (SDEs) using Wiener-Hermite expansion (WHE) has the advantage of converting the problem to a system of deterministic equations that can be solved efficiently using the standard deterministic numerical methods [1]. The main statistics, such as the mean, covariance, and higher order statistical moments, can be calculated by simple formulae involving only the deterministic Wiener-Hermite coefficients. In WHE approach, there is no randomness directly involved in the computations. One does not have to rely on pseudo random number generators, and there is no need to solve the SDEs repeatedly for many realizations. Instead, the deterministic system is solved only once. For previous research efforts see [2, 4].

  19. On Stable Wall Boundary Conditions for the Hermite Discretization of the Linearised Boltzmann Equation

    Science.gov (United States)

    Sarna, Neeraj; Torrilhon, Manuel

    2018-01-01

    We define certain criteria, using the characteristic decomposition of the boundary conditions and energy estimates, which a set of stable boundary conditions for a linear initial boundary value problem, involving a symmetric hyperbolic system, must satisfy. We first use these stability criteria to show the instability of the Maxwell boundary conditions proposed by Grad (Commun Pure Appl Math 2(4):331-407, 1949). We then recognise a special block structure of the moment equations which arises due to the recursion relations and the orthogonality of the Hermite polynomials; the block structure will help us in formulating stable boundary conditions for an arbitrary order Hermite discretization of the Boltzmann equation. The formulation of stable boundary conditions relies upon an Onsager matrix which will be constructed such that the newly proposed boundary conditions stay close to the Maxwell boundary conditions at least in the lower order moments.

  20. Adaptive Mesh Iteration Method for Trajectory Optimization Based on Hermite-Pseudospectral Direct Transcription

    Directory of Open Access Journals (Sweden)

    Humin Lei

    2017-01-01

    Full Text Available An adaptive mesh iteration method based on Hermite-Pseudospectral is described for trajectory optimization. The method uses the Legendre-Gauss-Lobatto points as interpolation points; then the state equations are approximated by Hermite interpolating polynomials. The method allows for changes in both number of mesh points and the number of mesh intervals and produces significantly smaller mesh sizes with a higher accuracy tolerance solution. The derived relative error estimate is then used to trade the number of mesh points with the number of mesh intervals. The adaptive mesh iteration method is applied successfully to the examples of trajectory optimization of Maneuverable Reentry Research Vehicle, and the simulation experiment results show that the adaptive mesh iteration method has many advantages.

  1. Lattice Boltzmann method for bosons and fermions and the fourth-order Hermite polynomial expansion.

    Science.gov (United States)

    Coelho, Rodrigo C V; Ilha, Anderson; Doria, Mauro M; Pereira, R M; Aibe, Valter Yoshihiko

    2014-04-01

    The Boltzmann equation with the Bhatnagar-Gross-Krook collision operator is considered for the Bose-Einstein and Fermi-Dirac equilibrium distribution functions. We show that the expansion of the microscopic velocity in terms of Hermite polynomials must be carried to the fourth order to correctly describe the energy equation. The viscosity and thermal coefficients, previously obtained by Yang et al. [Shi and Yang, J. Comput. Phys. 227, 9389 (2008); Yang and Hung, Phys. Rev. E 79, 056708 (2009)] through the Uehling-Uhlenbeck approach, are also derived here. Thus the construction of a lattice Boltzmann method for the quantum fluid is possible provided that the Bose-Einstein and Fermi-Dirac equilibrium distribution functions are expanded to fourth order in the Hermite polynomials.

  2. Generalized Hermite polynomials in superspace as eigenfunctions of the supersymmetric rational CMS model

    CERN Document Server

    Desrosiers, P; Mathieu, P; Desrosiers, Patrick; Lapointe, Luc; Mathieu, Pierre

    2003-01-01

    We present two constructions of the orthogonal eigenfunctions of the supersymmetric extension of the rational Calogero-Moser-Sutherland model with harmonic confinement. These eigenfunctions are the superspace extension of the generalized Hermite (or Hi-Jack) polynomials. The conserved quantities of the rational supersymmetric model are first related to their trigonometric relatives through a similarity transformation. This leads to a simple expression for the generalized Hermite superpolynomials as a differential operator acting on the corresponding Jack superpolynomials. The second construction relies on the action of the Hamiltonian on the supermonomial basis. This translates into determinantal expressions for the Hamiltonian's eigenfunctions. As an aside, the maximal superintegrability of the supersymmetric rational Calogero-Moser-Sutherland model is demonstrated.

  3. Applying inversion to construct planar, rational spirals that satisfy two-point G(2) Hermite data

    CERN Document Server

    Kurnosenko, A

    2010-01-01

    A method of two-point G(2) Hermite interpolation with spirals is proposed. To construct a sought for curve, the inversion is applied to an arc of some other spiral. To illustrate the method, inversions of parabola are considered in detail. The resulting curve is 4th degree rational. The method allows the matching of a wide range of boundary conditions, including those which require an inflection. Although not all G(2) Hermite data can be matched with a spiral generated from a parabolic arc, introducing one intermediate G(2) data solves the problem. Expanding the method by involving other spirals arcs is also discussed. (C) 2009 Elsevier B.V. All rights reserved.

  4. On the representation of the diffracted field of Hermite-Gaussian modes in an alien basis and the young diffraction principle

    International Nuclear Information System (INIS)

    Smirnov, V.N.; Strokovskii, G.A.

    1994-01-01

    An analytical form of expansion coefficients of a diffracted field for an arbitrary Hermite-Gaussian beam in an alien Hermite-Gaussian basis is obtained. A possible physical interpretation of the well-known Young phenomenological diffraction principle and experiments on diffraction of Hermite-Gaussian beams of the lowest types (n = 0 - 5) from half-plane are discussed. The case of nearly homogenous expansion corresponding to misalignment and mismatch of optical systems is also analyzed. 7 refs., 2 figs

  5. Hermite-Hadamard Type Integral Inequalities for Functions Whose Second-Order Mixed Derivatives Are Coordinated (s,m-P-Convex

    Directory of Open Access Journals (Sweden)

    Yu-Mei Bai

    2018-01-01

    Full Text Available We establish some new Hermite-Hadamard type integral inequalities for functions whose second-order mixed derivatives are coordinated (s,m-P-convex. An expression form of Hermite-Hadamard type integral inequalities via the beta function and the hypergeometric function is also presented. Our results provide a significant complement to the work of Wu et al. involving the Hermite-Hadamard type inequalities for coordinated (s,m-P-convex functions in an earlier article.

  6. Wigner distribution function of Hermite-cosine-Gaussian beams through an apertured optical system.

    Science.gov (United States)

    Sun, Dong; Zhao, Daomu

    2005-08-01

    By introducing the hard-aperture function into a finite sum of complex Gaussian functions, the approximate analytical expressions of the Wigner distribution function for Hermite-cosine-Gaussian beams passing through an apertured paraxial ABCD optical system are obtained. The analytical results are compared with the numerically integrated ones, and the absolute errors are also given. It is shown that the analytical results are proper and that the calculation speed for them is much faster than for the numerical results.

  7. Design of high-order rotation invariants from Gaussian-Hermite moments

    Czech Academy of Sciences Publication Activity Database

    Yang, Bo; Flusser, Jan; Suk, Tomáš

    2015-01-01

    Roč. 113, č. 1 (2015), s. 61-67 ISSN 0165-1684 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : Rotationinvariants * Geometric moments * Gaussian–Hermite moments * Recurrentrelation Subject RIV: JD - Computer Applications, Robotics Impact factor: 2.063, year: 2015 http://library.utia.cas.cz/separaty/2015/ZOI/flusser-0441266.pdf

  8. Hermite Functional Link Neural Network for Solving the Van der Pol-Duffing Oscillator Equation.

    Science.gov (United States)

    Mall, Susmita; Chakraverty, S

    2016-08-01

    Hermite polynomial-based functional link artificial neural network (FLANN) is proposed here to solve the Van der Pol-Duffing oscillator equation. A single-layer hermite neural network (HeNN) model is used, where a hidden layer is replaced by expansion block of input pattern using Hermite orthogonal polynomials. A feedforward neural network model with the unsupervised error backpropagation principle is used for modifying the network parameters and minimizing the computed error function. The Van der Pol-Duffing and Duffing oscillator equations may not be solved exactly. Here, approximate solutions of these types of equations have been obtained by applying the HeNN model for the first time. Three mathematical example problems and two real-life application problems of Van der Pol-Duffing oscillator equation, extracting the features of early mechanical failure signal and weak signal detection problems, are solved using the proposed HeNN method. HeNN approximate solutions have been compared with results obtained by the well known Runge-Kutta method. Computed results are depicted in term of graphs. After training the HeNN model, we may use it as a black box to get numerical results at any arbitrary point in the domain. Thus, the proposed HeNN method is efficient. The results reveal that this method is reliable and can be applied to other nonlinear problems too.

  9. Shell occupation by the South Atlantic endemic hermit crab Loxopagurus loxochelis (Moreira, 1901 (Anomura: Diogenidae

    Directory of Open Access Journals (Sweden)

    Israel Fernandes Frameschi

    Full Text Available The evaluation of population characteristics, particularly those of endemic species, aids in population preservation and management. Hermit crabs present an innate behavior of occupying shells, which tends to individual needs and limits their distribution. This study characterized the pattern of occupation of gastropod shells by the hermit Loxopagurus loxochelis in three bays of the southwestern coast of Brazil. Monthly collections were made from January/1998 to December/1999 in the bays Ubatumirim (UBM, Ubatuba (UBA and Mar Virado (MV with a shrimping boat. Overall, ten species of gastropod shells were occupied by L. loxochelis. The shell of Olivancillaria urceus represented 66.8% of those occupied. Morphometric relationships demonstrated a differential occupation of the more abundant shells among demographic groups, where most of the males occupied O. urceus, non-ovigerous females occupied O. urceus and Buccinanops cochlidium, and ovigerous females occupied B. cochlidium and Stramonita haemastoma. Most of the individuals occupied the more abundant shells, considered adequate for the morphology of this hermit crab species. Thus, the studied bays seem to be stable and propitious environments for population perpetuation and the settlement of new individuals.

  10. 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.

  11. Tropical Rainforests.

    Science.gov (United States)

    Nigh, Ronald B.; Nations, James D.

    1980-01-01

    Presented is a summary of scientific knowledge about the rainforest environment, a tropical ecosystem in danger of extermination. Topics include the current state of tropical rainforests, the causes of rainforest destruction, and alternatives of rainforest destruction. (BT)

  12. 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...

  13. 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...

  14. 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

  15. Tropical Glaciers

    Science.gov (United States)

    Fountain, Andrew

    The term "tropical glacier" calls to mind balmy nights and palm trees on one hand and cold, blue ice on the other. Certainly author Gabriel Garcia Marqez exploited this contrast in One Hundred Years of Solitude. We know that tropical fish live in warm, Sun-kissed waters and tropical plants provide lush, dense foliage populated by colorful tropical birds. So how do tropical glaciers fit into this scene? Like glaciers everywhere, tropical glaciers form where mass accumulation—usually winter snow—exceeds mass loss, which is generally summer melt. Thus, tropical glaciers exist at high elevations where precipitation can occur as snowfall exceeds melt and sublimation losses, such as the Rwenzori Mountains in east Africa and the Maoke Range of Irian Jaya.

  16. Tropical radioecology

    CERN Document Server

    Baxter, M

    2012-01-01

    Tropical Radioecology is a guide to the wide range of scientific practices and principles of this multidisciplinary field. It brings together past and present studies in the tropical and sub-tropical areas of the planet, highlighting the unique aspects of tropical systems. Until recently, radioecological models for tropical environments have depended upon data derived from temperate environments, despite the differences of these regions in terms of biota and abiotic conditions. Since radioactivity can be used to trace environmental processes in humans and other biota, this book offers examples of studies in which radiotracers have been used to assess biokinetics in tropical biota. Features chapters, co-authored by world experts, that explain the origins, inputs, distribution, behaviour, and consequences of radioactivity in tropical and subtropical systems. Provides comprehensive lists of relevant data and identifies current knowledge gaps to allow for targeted radioecological research in the future. Integrate...

  17. 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.

  18. On the ecology of Coenobita clypeatus in Curaçao with reference to reproduction, water economy and osmoregulation in terrestrial hermit crabs

    NARCIS (Netherlands)

    Wilde, de P.A.W.J.

    1973-01-01

    1. This paper deals with various aspects of the life-history, ecology, water management and osmoregulation of the West-Indian land hermit crab Coenobita clypeatus (Herbst) in Curaçao, Netherlands Antilles. 2. Land hermit crabs belonging to the family Coenobitidae may be considered as one of the most

  19. 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

  20. Scaling of olfactory antennae of the terrestrial hermit crabs Coenobita rugosus and Coenobita perlatus during ontogeny

    Directory of Open Access Journals (Sweden)

    Lindsay D. Waldrop

    2014-08-01

    Full Text Available Although many lineages of terrestrial crustaceans have poor olfactory capabilities, crabs in the family Coenobitidae, including the terrestrial hermit crabs in the genus Coenobita, are able to locate food and water using olfactory antennae (antennules to capture odors from the surrounding air. Terrestrial hermit crabs begin their lives as small marine larvae and must find a suitable place to undergo metamorphosis into a juvenile form, which initiates their transition to land. Juveniles increase in size by more than an order of magnitude to reach adult size. Since odor capture is a process heavily dependent on the size and speed of the antennules and physical properties of the fluid, both the transition from water to air and the large increase in size during ontogeny could impact odor capture. In this study, we examine two species of terrestrial hermit crabs, Coenobita perlatus H. Milne-Edwards and Coenobita rugosus H. Milne-Edwards, to determine how the antennule morphometrics and kinematics of flicking change in comparison to body size during ontogeny, and how this scaling relationship could impact odor capture by using a simple model of mass transport in flow. Many features of the antennules, including the chemosensory sensilla, scaled allometrically with carapace width and increased slower than expected by isometry, resulting in relatively larger antennules on juvenile animals. Flicking speed scaled as expected with isometry. Our mass-transport model showed that allometric scaling of antennule morphometrics and kinematics leads to thinner boundary layers of attached fluid around the antennule during flicking and higher odorant capture rates as compared to antennules which scaled isometrically. There were no significant differences in morphometric or kinematic measurements between the two species.

  1. Expression of ionotropic receptors in terrestrial hermit crab’s olfactory sensory neurons

    Directory of Open Access Journals (Sweden)

    Katrin Christine Groh-Lunow

    2015-02-01

    Full Text Available Coenobitidae are one out of at least five crustacean lineages which independently succeeded in the transition from water to land. This change in lifestyle required adaptation of the peripheral olfactory organs, the antennules, in order to sense chemical cues in the new terrestrial habitat. Hermit crab olfactory aesthetascs are arranged in a field on the distal segment of the antennular flagellum. Aesthetascs house approximately 300 dendrites with their cell bodies arranged in spindle-like complexes of ca. 150 cell bodies each. While the aesthetascs of aquatic crustaceans have been shown to be the place of odor uptake and previous studies identified ionotropic receptors (IRs as the putative chemosensory receptors expressed in decapod antennules, the expression of IRs besides the IR co-receptors IR25a and IR93a in olfactory sensory neurons (OSNs has not been documented yet. Our goal was to reveal the expression and distribution pattern of non-co-receptor IRs in OSNs of Coenobita clypeatus, a terrestrial hermit crab, with RNA in situ hybridization. We expanded our previously published RNAseq dataset, and revealed 22 novel IR candidates in the Coenobita antennules. We then used RNA probes directed against three different IRs to visualize their expression within the OSN cell body complexes. Furthermore we aimed to characterize ligand spectra of single aesthetascs by recording local field potentials and responses from individual dendrites. This also allowed comparison to functional data from insect OSNs expressing antennal IRs. We show that this orphan receptor subgroup with presumably non-olfactory function in insects is likely the basis of olfaction in terrestrial hermit crabs.

  2. Microscopic universality of complex matrix model correlation functions at weak non-Hermiticity

    International Nuclear Information System (INIS)

    Akemann, G.

    2002-01-01

    The microscopic correlation functions of non-chiral random matrix models with complex eigenvalues are analyzed for a wide class of non-Gaussian measures. In the large-N limit of weak non-Hermiticity, where N is the size of the complex matrices, we can prove that all k-point correlation functions including an arbitrary number of Dirac mass terms are universal close to the origin. To this aim we establish the universality of the asymptotics of orthogonal polynomials in the complex plane. The universality of the correlation functions then follows from that of the kernel of orthogonal polynomials and a mapping of massive to massless correlators

  3. Coherent mode decomposition using mixed Wigner functions of Hermite-Gaussian beams.

    Science.gov (United States)

    Tanaka, Takashi

    2017-04-15

    A new method of coherent mode decomposition (CMD) is proposed that is based on a Wigner-function representation of Hermite-Gaussian beams. In contrast to the well-known method using the cross spectral density (CSD), it directly determines the mode functions and their weights without solving the eigenvalue problem. This facilitates the CMD of partially coherent light whose Wigner functions (and thus CSDs) are not separable, in which case the conventional CMD requires solving an eigenvalue problem with a large matrix and thus is numerically formidable. An example is shown regarding the CMD of synchrotron radiation, one of the most important applications of the proposed method.

  4. Solution of the neutron transport equation by means of Hermite-Ssub(infinity)-theory

    International Nuclear Information System (INIS)

    Brandt, D.; Haelg, W.; Mennig, J.

    1979-01-01

    A stable numerical approximation Hsub(α)-Ssub(infinity) is obtained through the use of Hermite's method of order α(Hsub(α)) in the spatial integration of the ID neutron transport equation. The theory for α = 1 is applied to a one-group shielding problem. Numerical calculations show the new method to converge much faster than earlier versions of Ssub(infinity)-theory. Comparison of H 1 - Ssub(infinity) with the well-known Ssub(N)-code ANISN indicates a large gain in computing time for the former. (Auth.)

  5. Hermite-Pade approximation approach to hydromagnetic flows in convergent-divergent channels

    International Nuclear Information System (INIS)

    Makinde, O.D.

    2005-10-01

    The problem of two-dimensional, steady, nonlinear flow of an incompressible conducting viscous fluid in convergent-divergent channels under the influence of an externally applied homogeneous magnetic field is studied using a special type of Hermite-Pade approximation approach. This semi-numerical scheme offers some advantages over solutions obtained by using traditional methods such as finite differences, spectral method, shooting method, etc. It reveals the analytical structure of the solution function and the important properties of overall flow structure including velocity field, flow reversal control and bifurcations are discussed. (author)

  6. Hermite interpolant multiscaling functions for numerical solution of the convection diffusion equations

    Directory of Open Access Journals (Sweden)

    Elmira Ashpazzadeh

    2018-04-01

    Full Text Available A numerical technique based on the Hermite interpolant multiscaling functions is presented for the solution of Convection-diusion equations. The operational matrices of derivative, integration and product are presented for multiscaling functions and are utilized to reduce the solution of linear Convection-diusion equation to the solution of algebraic equations. Because of sparsity of these matrices, this method is computationally very attractive and reduces the CPU time and computer memory. Illustrative examples are included to demonstrate the validity and applicability of the new technique.

  7. Phase-based motion magnification video for monitoring of vital signals using the Hermite transform

    Science.gov (United States)

    Brieva, Jorge; Moya-Albor, Ernesto

    2017-11-01

    In this paper we present a new Eulerian phase-based motion magnification technique using the Hermite Transform (HT) decomposition that is inspired in the Human Vision System (HVS). We test our method in one sequence of the breathing of a newborn baby and on a video sequence that shows the heartbeat on the wrist. We detect and magnify the heart pulse applying our technique. Our motion magnification approach is compared to the Laplacian phase based approach by means of quantitative metrics (based on the RMS error and the Fourier transform) to measure the quality of both reconstruction and magnification. In addition a noise robustness analysis is performed for the two methods.

  8. Operational matrices with respect to Hermite polynomials and their applications in solving linear dierential equations with variable coecients

    Directory of Open Access Journals (Sweden)

    A. Aminataei

    2014-05-01

    Full Text Available In this paper, a new and ecient approach is applied for numerical approximation of the linear dierential equations with variable coecients based on operational matrices with respect to Hermite polynomials. Explicit formulae which express the Hermite expansioncoecients for the moments of derivatives of any dierentiable function in terms of the original expansion coecients of the function itself are given in the matrix form. The mainimportance of this scheme is that using this approach reduces solving the linear dierentialequations to solve a system of linear algebraic equations, thus greatly simplifying the problem. In addition, two experiments are given to demonstrate the validity and applicability of the method

  9. Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning

    Directory of Open Access Journals (Sweden)

    Samantha J. Tol

    2016-07-01

    Full Text Available Dugongs (Dugong dugon are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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 ...

  16. 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 ...

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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.

  4. Sixth- and eighth-order Hermite integrator for N-body simulations

    Science.gov (United States)

    Nitadori, Keigo; Makino, Junichiro

    2008-10-01

    We present sixth- and eighth-order Hermite integrators for astrophysical N-body simulations, which use the derivatives of accelerations up to second-order ( snap) and third-order ( crackle). These schemes do not require previous values for the corrector, and require only one previous value to construct the predictor. Thus, they are fairly easy to implement. The additional cost of the calculation of the higher-order derivatives is not very high. Even for the eighth-order scheme, the number of floating-point operations for force calculation is only about two times larger than that for traditional fourth-order Hermite scheme. The sixth-order scheme is better than the traditional fourth-order scheme for most cases. When the required accuracy is very high, the eighth-order one is the best. These high-order schemes have several practical advantages. For example, they allow a larger number of particles to be integrated in parallel than the fourth-order scheme does, resulting in higher execution efficiency in both general-purpose parallel computers and GRAPE systems.

  5. Hermite-Gaussian beams with self-forming spiral phase distribution

    Science.gov (United States)

    Zinchik, Alexander A.; Muzychenko, Yana B.

    2014-05-01

    Spiral laser beams is a family of laser beams that preserve the structural stability up to scale and rotate with the propagation. Properties of spiral beams are of practical interest for laser technology, medicine and biotechnology. Researchers use a spiral beams for movement and manipulation of microparticles. Spiral beams have a complicated phase distribution in cross section. This paper describes the results of analytical and computer simulation of Hermite-Gaussian beams with self-forming spiral phase distribution. In the simulation used a laser beam consisting of the sum of the two modes HG TEMnm and TEMn1m1. The coefficients n1, n, m1, m were varied. Additional phase depending from the coefficients n, m, m1, n1 imposed on the resulting beam. As a result, formed the Hermite Gaussian beam phase distribution which takes the form of a spiral in the process of distribution. For modeling was used VirtualLab 5.0 (manufacturer LightTrans GmbH).

  6. 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

  7. Development and Evaluation of Compact Robot Imitating a Hermit Crab for Inspecting the Outer Surface of Pipes

    Directory of Open Access Journals (Sweden)

    Naoto Imajo

    2015-01-01

    Full Text Available Terrestrial hermit crabs which are a type of hermit crabs live on land, whereas typical hermit crabs inhabit the sea. They have an ability of climbing a tree vertically. Their claws allow them to hang on the tree. In this study, an outer-pipe inspection robot was developed. Its locomotion mechanism was developed in imitation of the terrestrial hermit crab’s claws. It is equipped with two rimless wheels. Each of the spokes is tipped with a neodymium magnet, which allows the robot to remain attached to even a vertical steel pipe. Moreover, the robot has a mechanism for adjusting the camber angle of the right and left wheels, allowing it to tightly grip pipes with different diameters. Experiments were conducted to check the performance of the robot using steel pipes with different diameters, placed horizontally, vertically, or obliquely. The robot attempted to move a certain distance along a pipe, and its success rate was measured. It was found that the robot could successfully travel along pipes with vertical orientations, although it sometimes fell from oblique or horizontal pipes. The most likely reason for this is identified and discussed. Certain results were obtained in laboratory. Further experiments in actual environment are required.

  8. SPECIES INVENTORY OF AMPHIBIOUS FISH IN INTERTIDAL ZONE OF NGRENEHAN, NGOBARAN AND NGUYAHAN COASTELS, GUNUNG KIDUL, YOGYAKARTA

    Directory of Open Access Journals (Sweden)

    Sukiya Sukiya

    2015-10-01

    Full Text Available Tropical region is high on faunal diversity including vertebrates and invertebrates. Research on diversity of amphibious fish in Intertidal zone of  Yogyakarta southern coast is still limited so there is no complete records regarding these unique fish. This research aimed to know the diversity of amphibious fish in three beaches of Yogyakarta southern coast, namely pantai Ngrenehan, Ngobaran dan Nguyahan. Fish sampling were conducted using random sampling method combined with observational method. Fish were collected using small nets then identified to species rank. The total length of each fish were measured and recorded. Few individuals of the same species were sacrificed as voucher specimens. The result showed that in pantai Ngrenehan, Ngobaran, and Nguyahan, five different species of amphibius fish were found, which are Cabillus lacertops, Bathygobius fuscus, Enneapterygus sp., Blenniella cyanostigma, and Blenniella caudolineata. Cabillus lacertops was found in all of sampling locations. Enneapterygus sp. was found in pantai Nguyahan while Bathigobius fuscus, and Blenniella caudolineata can only be found in pantai Ngrenehan. Further studies regarding the adaptation, ecological features, taxonomy and biological reproduction of Yogyakarta southern coast’s  amphibious fish are still needed.   Keywords: Inventarization, amphbious fish, intertidal zone, Yogyakarta southern coast

  9. Mechanisms causing size differences of the land hermit crab Coenobita rugosus among eco-islands in Southern Taiwan.

    Directory of Open Access Journals (Sweden)

    Chia-Hsuan Hsu

    Full Text Available Numerous environmental factors can influence body size. Comparing populations in different ecological contexts is one potential approach to elucidating the most critical of such factors. In the current study, we found that the body size of the land hermit crab Coenobita rugosus was significantly larger on Dongsha Island in the South China Sea than on other eco-islands around Southern Taiwan. We hypothesized that this could be due to differences in (1 shell resources, (2 parasite impact, (3 competition, (4 predation, and (5 food. We found no supporting evidence for the first three hypotheses; the shells used by the hermit crabs on Dongsha were in poorer condition than were those used elsewhere, extremely few individuals in the region had ectoparasites, and the density of hermit crabs varied considerably among localities within each island. However, significantly higher percentages of C. rugosus reached age 3 years on Dongsha than at Siziwan bay in Taiwan. Two growth rate indices inferred from size structures suggested faster growth on Dongsha than at Siziwan. The condition index (i.e., the body mass/shield length ratio of C. rugosus was also greater on Dongsha than at Siziwan. Therefore, Dongsha hermit crabs seem to have superior diet and growth performance. Seagrass debris accumulation at the shore of Dongsha was considerable, whereas none was observed at Siziwan or on the other islands, where dicot leaves were the dominant food item for the vegetarian hermit crabs. We then experimentally evaluated the possible role of seagrass as food for C. rugosus. The crabs on Dongsha preferred seagrass to dicot leaves, and their growth increment was faster when they fed on seagrass than when they fed on dicot leaves; no such differences were found in the Siziwan hermit crabs. The aforementioned results are compatible with the food hypothesis explaining the size differences among the islands. The predator hypothesis could explain the greater life span but

  10. 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.

  11. 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...

  12. Pythagorean hodograph spline spirals that match G3 Hermite data from circles

    KAUST Repository

    Li, Zhong; Ait-Haddou, Rachid; Biard, Luc

    2015-01-01

    A construction is given for a G3 piecewise rational Pythagorean hodograph convex spiral which interpolates two G3 Hermite data associated with two non-concentric circles, one being inside the other. The spiral solution is of degree 7 and is the involute of a G2 convex curve, referred to as the evolute solution, with prescribed length, and composed of two PH quartic curves. Conditions for G3 continuous contact with circles are then studied and it turns out that an ordinary cusp at each end of the evolute solution is required. Thus, geometric properties of a family of PH polynomial quartics, allowing to generate such an ordinary cusp at one end, are studied. Finally, a constructive algorithm is described with illustrative examples.

  13. Solution of stochastic nonlinear PDEs using Wiener-Hermite expansion of high orders

    KAUST Repository

    El Beltagy, Mohamed

    2016-01-06

    In this work, the Wiener-Hermite Expansion (WHE) is used to solve stochastic nonlinear PDEs excited with noise. The generation of the equivalent set of deterministic integro-differential equations is automated and hence allows for high order terms of WHE. The automation difficulties are discussed, solved and implemented to output the final system to be solved. A numerical Pikard-like algorithm is suggested to solve the resulting deterministic system. The automated WHE is applied to the 1D diffusion equation and to the heat equation. The results are compared with previous solutions obtained with WHEP (WHE with perturbation) technique. The solution obtained using the suggested WHE technique is shown to be the limit of the WHEP solutions with infinite number of corrections. The automation is extended easily to account for white-noise of higher dimension and for general nonlinear PDEs.

  14. Solution of stochastic nonlinear PDEs using Wiener-Hermite expansion of high orders

    KAUST Repository

    El Beltagy, Mohamed

    2016-01-01

    In this work, the Wiener-Hermite Expansion (WHE) is used to solve stochastic nonlinear PDEs excited with noise. The generation of the equivalent set of deterministic integro-differential equations is automated and hence allows for high order terms of WHE. The automation difficulties are discussed, solved and implemented to output the final system to be solved. A numerical Pikard-like algorithm is suggested to solve the resulting deterministic system. The automated WHE is applied to the 1D diffusion equation and to the heat equation. The results are compared with previous solutions obtained with WHEP (WHE with perturbation) technique. The solution obtained using the suggested WHE technique is shown to be the limit of the WHEP solutions with infinite number of corrections. The automation is extended easily to account for white-noise of higher dimension and for general nonlinear PDEs.

  15. Novel quadrilateral elements based on explicit Hermite polynomials for bending of Kirchhoff-Love plates

    Science.gov (United States)

    Beheshti, Alireza

    2018-03-01

    The contribution addresses the finite element analysis of bending of plates given the Kirchhoff-Love model. To analyze the static deformation of plates with different loadings and geometries, the principle of virtual work is used to extract the weak form. Following deriving the strain field, stresses and resultants may be obtained. For constructing four-node quadrilateral plate elements, the Hermite polynomials defined with respect to the variables in the parent space are applied explicitly. Based on the approximated field of displacement, the stiffness matrix and the load vector in the finite element method are obtained. To demonstrate the performance of the subparametric 4-node plate elements, some known, classical examples in structural mechanics are solved and there are comparisons with the analytical solutions available in the literature.

  16. Implementation of Associated Hermite FDTD Method in Handling INBCs for Shielding Analysis

    Directory of Open Access Journals (Sweden)

    Lihua Shi

    2016-01-01

    Full Text Available For modeling of electrically thin conductive shields, the unconditionally stable Associated Hermite (AH FDTD scheme is combined with the impedance network boundary conditions (INBCs in this paper. The two-port network equations of INBCs in frequency domain are transformed into AH domain to represent the relationship of tangential components of the electric and magnetic fields at faces of the shield. The established AH-INBCs shielding boundaries are incorporated into a set of implicit equations to calculate the expansion coefficients vectors of electromagnetic fields in the computational domain. The method is free of CFL condition and no convolution integral operation for solving the conventional INBCs-FDTD is involved. Numerical example shows that, compared with analytical solutions and conventional FDTD method, the proposed algorithm is efficient and accurate.

  17. New one-flavor hybrid Monte Carlo simulation method for lattice fermions with γ5 hermiticity

    International Nuclear Information System (INIS)

    Ogawa, Kenji

    2011-01-01

    We propose a new method for Hybrid Monte Carlo (HMC) simulations with odd numbers of dynamical fermions on the lattice. It employs a different approach from polynomial or rational HMC. In this method, γ 5 hermiticity of the lattice Dirac operators is crucial and it can be applied to Wilson, domain-wall, and overlap fermions. We compare HMC simulations with two degenerate flavors and (1+1) degenerate flavors using optimal domain-wall fermions. The ratio of the efficiency, (number of accepted trajectories)/(simulation time), is about 3:2. The relation between pseudofermion action of chirally symmetric lattice fermions in four-dimensional (overlap) and five-dimensional (domain-wall) representation are also analyzed.

  18. A pair of biorthogonal polynomials for the Szegö-Hermite weight function

    Directory of Open Access Journals (Sweden)

    N. K. Thakare

    1988-01-01

    Full Text Available A pair of polynomial sequences {Snμ(x;k} and {Tmμ(x;k} where Snμ(x;k is of degree n in xk and Tmμ(x;k is of degree m in x, is constructed. It is shown that this pair is biorthogonal with respect to the Szegö-Hermite weight function |x|2μexp(−x2, (μ>−1/2 over the interval (−∞,∞ in the sense that∫−∞∞|x|2μexp(−x2Snμ(x;kTmμ(x;kdx=0,   ifm≠n                    ≠0,   ifm=nwhere m,n=0,1,2,… and k is an odd positive integer.

  19. Pythagorean hodograph spline spirals that match G3 Hermite data from circles

    KAUST Repository

    Li, Zhong

    2015-04-01

    A construction is given for a G3 piecewise rational Pythagorean hodograph convex spiral which interpolates two G3 Hermite data associated with two non-concentric circles, one being inside the other. The spiral solution is of degree 7 and is the involute of a G2 convex curve, referred to as the evolute solution, with prescribed length, and composed of two PH quartic curves. Conditions for G3 continuous contact with circles are then studied and it turns out that an ordinary cusp at each end of the evolute solution is required. Thus, geometric properties of a family of PH polynomial quartics, allowing to generate such an ordinary cusp at one end, are studied. Finally, a constructive algorithm is described with illustrative examples.

  20. 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...

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Distribuição temporal do ermitão Clibanarius vittatus (Anomura, Diogenidae no litoral do Paraná Temporal distribution of the hermit crab Clibanarius vittatus (Anomura, Diogenidae from Paraná State coast, Brazil

    Directory of Open Access Journals (Sweden)

    Sara R. Sampaio

    2009-09-01

    Full Text Available Um estudo sobre a flutuação temporal da estrutura populacional do ermitão Clibanarius vittatus (Bosc, 1802 foi realizado no Baixio Mirim, Baía de Guaratuba, Estado do Paraná, Brasil (25°52'S, 48°36'W. Clibanarius vittatus é uma espécie largamente estudada, entretanto estudos da biologia populacional desta em diferentes regiões são escassos. Coletas mensais foram realizadas na zona entremarés, de abril/2005 a março/2006. Foram obtidos 1187 ermitões, dos quais, 949 machos, 22 indivíduos intersexo, 204 fêmeas não ovígeras e 12 fêmeas ovígeras. O comprimento do escudo cefalotorácico (CEC foi medido e agrupado em 10 classes de tamanho. Machos ocorreram em 10 classes de CEC, enquanto fêmeas e intersexos em apenas seis. A razão de sexos total e mensal foi a favor dos machos. Todas as categorias demográficas estiveram presentes o ano inteiro, com exceção dos intersexos e das fêmeas ovígeras. Estas foram pouco frequentes e ocorreram do final da primavera até o outono, e em agosto de 2005. O período reprodutivo foi considerado contínuo-sazonal, com maior intensidade nos meses mais quentes. A razão de sexos nesta população, que é diferente das demais estudadas, corrobora a teoria de migração proposta para esta espécie. O presente estudo constitui o primeiro registro do período reprodutivo desta espécie em águas rasas de clima subtropical quente.A study on the temporal fluctuation of the population structure of the hermit crab Clibanarius vittatus (Bosc, 1802 was carried out at Baixio Mirim tideflat, Guaratuba Bay, Paraná State, southern Brazil (25°52'S, 48°36'W. Clibanarius vittatus is a species widely studied, but studies of population biology of these hermit crabs in different regions are scarce. Samplings were done in the intertidal zone, monthly, from April/2005 to March/2006. A total of 1187 hermit crabs were obtained, among which, 949 males, 22 intersexes, 204 non-ovigerous females and 12 ovigerous females

  7. 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

  8. 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.

  9. Upper temperature limits of tropical marine ectotherms: global warming implications.

    Directory of Open Access Journals (Sweden)

    Khanh Dung T Nguyen

    Full Text Available Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour(-1, the upper lethal temperature range of intertidal ectotherms was 41-52°C, but this range was narrower and reduced to 37-41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2-3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming.

  10. Tropical Deforestation.

    Science.gov (United States)

    Raven, Peter H.

    1988-01-01

    Outlines the deforestation problem and some efforts for solving the problem. Considers the impact of population growth, poverty, and ignorance. Includes a discussion of the current rapid decline in tropical forests, the consequences of destruction, and an outlook for the future. (YP)

  11. Impact of the changing ecology on intertidal polychaetes in an anthropogenically stressed tropical creek, India

    Digital Repository Service at National Institute of Oceanography (India)

    Quadros, G.; Sukumaran, S.; Athalye, R.P.

    of Bombay, India. Part I: quantification of heavy metal pollution of aquatic sediments and recogni- tion of environmental discriminants. Chem Geol 90:263– 283. doi:10.1016/0009-2541(91)90104-Y Sanders HL, Grassle JF, Hampson GR, Morse LS, Garner Price S...

  12. Diatoms of the microphytobenthic community: Population structure in a tropical intertidal sand flat

    Digital Repository Service at National Institute of Oceanography (India)

    Mitbavkar, S.; Anil, A.C

    stream_size 194926 stream_content_type text/plain stream_name Mar_Biol_140_41.pdf.txt stream_source_info Mar_Biol_140_41.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 C83C46 C77C105C116C...98C97C118C107C97C114 C225 C65C46C67C46 C65C110C105C108 C68C105C97C116C111C109C115 C111C102 C116C104C101 C109C105C99C114C111C112C104C121C116C111C98C101C110C116C104C105C99 C99C111C109C109C117C110C105C116C121C58 C112C111C112C117C108C97C116C105C111C110 C...

  13. Benthic dinoflagellate blooms in tropical intertidal rock pools: Elucidation of photoprotection mechanisms

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Rodrigues, R.V.; Paul, P.; Sathish, K.; Rafi, M.; Anil, A.C.

    (HT), mid tide (MT), and low tide (LT) zones on the rocky shores of Anjuna, Goa (India) facing the Arabian Sea. MT-RPs and LT-RPs were dominated by diatoms and HT-RPs by dinoflagellates due to the blooms of autotrophic benthic dinoflagellates belonging...

  14. Environmental drivers of temporal variability in DMS (P) in the surfwater of a tropical intertidal beach

    Digital Repository Service at National Institute of Oceanography (India)

    Pandey, S.S.; LokaBharathi, P.A.

    show that the average DMS concentration was highest during the monsoon season (7.64nM) followed by post-monsoon (6.71nM) and premonsoon(1.58nM) Consequently, the estimated sea-air flux of DMS is monsoon > post-monsoon > pre-monsoon at 24.75> 18.93> 2...

  15. 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

  16. A new class of generalized polynomials associated with Hermite and Bernoulli polynomials

    Directory of Open Access Journals (Sweden)

    M. A. Pathan

    2015-05-01

    Full Text Available In this paper, we introduce a new class of generalized  polynomials associated with  the modified Milne-Thomson's polynomials Φ_{n}^{(α}(x,ν of degree n and order α introduced by  Derre and Simsek.The concepts of Bernoulli numbers B_n, Bernoulli polynomials  B_n(x, generalized Bernoulli numbers B_n(a,b, generalized Bernoulli polynomials  B_n(x;a,b,c of Luo et al, Hermite-Bernoulli polynomials  {_HB}_n(x,y of Dattoli et al and {_HB}_n^{(α} (x,y of Pathan  are generalized to the one   {_HB}_n^{(α}(x,y,a,b,c which is called  the generalized  polynomial depending on three positive real parameters. Numerous properties of these polynomials and some relationships between B_n, B_n(x, B_n(a,b, B_n(x;a,b,c and {}_HB_n^{(α}(x,y;a,b,c  are established. Some implicit summation formulae and general symmetry identities are derived by using different analytical means and applying generating functions. These results extend some known summations and identities of generalized Bernoulli numbers and polynomials

  17. Hermite regularization of the lattice Boltzmann method for open source computational aeroacoustics.

    Science.gov (United States)

    Brogi, F; Malaspinas, O; Chopard, B; Bonadonna, C

    2017-10-01

    The lattice Boltzmann method (LBM) is emerging as a powerful engineering tool for aeroacoustic computations. However, the LBM has been shown to present accuracy and stability issues in the medium-low Mach number range, which is of interest for aeroacoustic applications. Several solutions have been proposed but are often too computationally expensive, do not retain the simplicity and the advantages typical of the LBM, or are not described well enough to be usable by the community due to proprietary software policies. An original regularized collision operator is proposed, based on the expansion of Hermite polynomials, that greatly improves the accuracy and stability of the LBM without significantly altering its algorithm. The regularized LBM can be easily coupled with both non-reflective boundary conditions and a multi-level grid strategy, essential ingredients for aeroacoustic simulations. Excellent agreement was found between this approach and both experimental and numerical data on two different benchmarks: the laminar, unsteady flow past a 2D cylinder and the 3D turbulent jet. Finally, most of the aeroacoustic computations with LBM have been done with commercial software, while here the entire theoretical framework is implemented using an open source library (palabos).

  18. Analysis of the finescale timing of repeated signals: does shell rapping in hermit crabs signal stamina?

    Science.gov (United States)

    Briffa; Elwood

    2000-01-01

    Hermit crabs, Pagurus bernhardus, sometimes exchange shells after a period of shell rapping, when the initiating or attacking crab brings its shell rapidly and repeatedly into contact with the shell of the noninitiator or defender in a series of bouts. Bouts are separated by pauses, and raps within bouts are separated by very short periods called 'gaps'. Since within-contest variation is missed when signals are studied by averaging performance rates over entire contests, we analysed the fine within-bout structure of this repeated, aggressive signal. We found that the pattern is consistent with high levels of fatigue in initiators. The duration of the gaps between individual raps increased both within bouts and from bout to bout, and we conclude that this activity is costly to perform. Furthermore, long pauses between bouts is correlated with increased vigour of rapping in the subsequent bout, which suggests that the pause allows for recovery from fatigue induced by rapping. These between-bout pauses may be assessed by noninitiators and provide a signal of stamina. Copyright 2000 The Association for the Study of Animal Behaviour.

  19. Viriato: a Fourier-Hermite spectral code for strongly magnetised fluid-kinetic plasma dynamics

    Science.gov (United States)

    Loureiro, Nuno; Dorland, William; Fazendeiro, Luis; Kanekar, Anjor; Mallet, Alfred; Zocco, Alessandro

    2015-11-01

    We report on the algorithms and numerical methods used in Viriato, a novel fluid-kinetic code that solves two distinct sets of equations: (i) the Kinetic Reduced Electron Heating Model equations [Zocco & Schekochihin, 2011] and (ii) the kinetic reduced MHD (KRMHD) equations [Schekochihin et al., 2009]. Two main applications of these equations are magnetised (Alfvnénic) plasma turbulence and magnetic reconnection. Viriato uses operator splitting to separate the dynamics parallel and perpendicular to the ambient magnetic field (assumed strong). Along the magnetic field, Viriato allows for either a second-order accurate MacCormack method or, for higher accuracy, a spectral-like scheme. Perpendicular to the field Viriato is pseudo-spectral, and the time integration is performed by means of an iterative predictor-corrector scheme. In addition, a distinctive feature of Viriato is its spectral representation of the parallel velocity-space dependence, achieved by means of a Hermite representation of the perturbed distribution function. A series of linear and nonlinear benchmarks and tests are presented, with focus on 3D decaying kinetic turbulence. Work partially supported by Fundação para a Ciência e Tecnologia via Grants UID/FIS/50010/2013 and IF/00530/2013.

  20. Scattering of aerosol particles by a Hermite-Gaussian beam in marine atmosphere.

    Science.gov (United States)

    Huang, Qingqing; Cheng, Mingjian; Guo, Lixin; Li, Jiangting; Yan, Xu; Liu, Songhua

    2017-07-01

    Based on the complex-source-point method and the generalized Lorenz-Mie theory, the scattering properties and polarization of aerosol particles by a Hermite-Gaussian (HG) beam in marine atmosphere is investigated. The influences of beam mode, beam width, and humidity on the scattered field are analyzed numerically. Results indicate that when the number of HG beam modes u (v) increase, the radar cross section of aerosol particles alternating appears at maximum and minimum values in the forward and backward scattering, respectively, because of the special petal-shaped distribution of the HG beam. The forward and backward scattering of aerosol particles decreases with the increase in beam waist. When beam waist is less than the radius of the aerosol particle, a minimum value is observed in the forward direction. The scattering properties of aerosol particles by the HG beam are more sensitive to the change in relative humidity compared with those by the plane wave and the Gaussian beam (GB). The HG beam shows superiority over the plane wave and the GB in detecting changes in the relative humidity of marine atmosphere aerosol. The effects of relative humidity on the polarization of the HG beam have been numerically analyzed in detail.

  1. Parallel iterative solution of the Hermite Collocation equations on GPUs II

    International Nuclear Information System (INIS)

    Vilanakis, N; Mathioudakis, E

    2014-01-01

    Hermite Collocation is a high order finite element method for Boundary Value Problems modelling applications in several fields of science and engineering. Application of this integration free numerical solver for the solution of linear BVPs results in a large and sparse general system of algebraic equations, suggesting the usage of an efficient iterative solver especially for realistic simulations. In part I of this work an efficient parallel algorithm of the Schur complement method coupled with Bi-Conjugate Gradient Stabilized (BiCGSTAB) iterative solver has been designed for multicore computing architectures with a Graphics Processing Unit (GPU). In the present work the proposed algorithm has been extended for high performance computing environments consisting of multiprocessor machines with multiple GPUs. Since this is a distributed GPU and shared CPU memory parallel architecture, a hybrid memory treatment is needed for the development of the parallel algorithm. The realization of the algorithm took place on a multiprocessor machine HP SL390 with Tesla M2070 GPUs using the OpenMP and OpenACC standards. Execution time measurements reveal the efficiency of the parallel implementation

  2. Study on Meshfree Hermite Radial Point Interpolation Method for Flexural Wave Propagation Modeling and Damage Quantification

    Directory of Open Access Journals (Sweden)

    Hosein Ghaffarzadeh

    Full Text Available Abstract This paper investigates the numerical modeling of the flexural wave propagation in Euler-Bernoulli beams using the Hermite-type radial point interpolation method (HRPIM under the damage quantification approach. HRPIM employs radial basis functions (RBFs and their derivatives for shape function construction as a meshfree technique. The performance of Multiquadric(MQ RBF to the assessment of the reflection ratio was evaluated. HRPIM signals were compared with the theoretical and finite element responses. Results represent that MQ is a suitable RBF for HRPIM and wave propagation. However, the range of the proper shape parameters is notable. The number of field nodes is the main parameter for accurate wave propagation modeling using HRPIM. The size of support domain should be less thanan upper bound in order to prevent high error. With regard to the number of quadrature points, providing the minimum numbers of points are adequate for the stable solution, but the existence of more points in damage region does not leads to necessarily the accurate responses. It is concluded that the pure HRPIM, without any polynomial terms, is acceptable but considering a few terms will improve the accuracy; even though more terms make the problem unstable and inaccurate.

  3. Stability of nonlinear Vlasov-Poisson equilibria through spectral deformation and Fourier-Hermite expansion.

    Science.gov (United States)

    Siminos, Evangelos; Bénisti, Didier; Gremillet, Laurent

    2011-05-01

    We study the stability of spatially periodic, nonlinear Vlasov-Poisson equilibria as an eigenproblem in a Fourier-Hermite basis (in the space and velocity variables, respectively) of finite dimension, N. When the advection term in the Vlasov equation is dominant, the convergence with N of the eigenvalues is rather slow, limiting the applicability of the method. We use the method of spectral deformation introduced by Crawford and Hislop [Ann. Phys. (NY) 189, 265 (1989)] to selectively damp the continuum of neutral modes associated with the advection term, thus accelerating convergence. We validate and benchmark the performance of our method by reproducing the kinetic dispersion relation results for linear (spatially homogeneous) equilibria. Finally, we study the stability of a periodic Bernstein-Greene-Kruskal mode with multiple phase-space vortices, compare our results with numerical simulations of the Vlasov-Poisson system, and show that the initial unstable equilibrium may evolve to different asymptotic states depending on the way it was perturbed. © 2011 American Physical Society

  4. Do terrestrial hermit crabs sniff? Air flow and odorant capture by flicking antennules.

    Science.gov (United States)

    Waldrop, Lindsay D; Koehl, M A R

    2016-01-01

    Capture of odorant molecules by olfactory organs from the surrounding fluid is the first step of smelling. Sniffing intermittently moves fluid across sensory surfaces, increasing delivery rates of molecules to chemosensory receptors and providing discrete odour samples. Aquatic malacostracan crustaceans sniff by flicking olfactory antennules bearing arrays of chemosensory hairs (aesthetascs), capturing water in the arrays during downstroke and holding the sample during return stroke. Terrestrial malacostracans also flick antennules, but how their flicking affects odour capture from air is not understood. The terrestrial hermit crab, Coenobita rugosus, uses antennules bearing shingle-shaped aesthetascs to capture odours. We used particle image velocimetry to measure fine-scale fluid flow relative to a dynamically scaled physical model of a flicking antennule, and computational simulations to calculate diffusion to aesthetascs by odorant molecules carried in that flow. Air does not flow into the aesthetasc array during flick downstrokes or recovery strokes. Odorants are captured from air flowing around the outside of the array during flick downstrokes, when aesthetascs face upstream and molecule capture rates are 21% higher than for stationary antennules. Bursts of flicking followed by pauses deliver discrete odour samples to olfactory sensors, causing intermittency in odour capture by a different mechanism than aquatic crustaceans use. © 2016 The Author(s).

  5. Hermite-cosine-Gaussian laser beam and its propagation characteristics in turbulent atmosphere.

    Science.gov (United States)

    Eyyuboğlu, Halil Tanyer

    2005-08-01

    Hermite-cosine-Gaussian (HcosG) laser beams are studied. The source plane intensity of the HcosG beam is introduced and its dependence on the source parameters is examined. By application of the Fresnel diffraction integral, the average receiver intensity of HcosG beam is formulated for the case of propagation in turbulent atmosphere. The average receiver intensity is seen to reduce appropriately to various special cases. When traveling in turbulence, the HcosG beam initially experiences the merging of neighboring beam lobes, and then a TEM-type cosh-Gaussian beam is formed, temporarily leading to a plain cosh-Gaussian beam. Eventually a pure Gaussian beam results. The numerical evaluation of the normalized beam size along the propagation axis at selected mode indices indicates that relative spreading of higher-order HcosG beam modes is less than that of the lower-order counterparts. Consequently, it is possible at some propagation distances to capture more power by using higher-mode-indexed HcosG beams.

  6. Dynamics of one-dimensional self-gravitating systems using Hermite-Legendre polynomials

    Science.gov (United States)

    Barnes, Eric I.; Ragan, Robert J.

    2014-01-01

    The current paradigm for understanding galaxy formation in the Universe depends on the existence of self-gravitating collisionless dark matter. Modelling such dark matter systems has been a major focus of astrophysicists, with much of that effort directed at computational techniques. Not surprisingly, a comprehensive understanding of the evolution of these self-gravitating systems still eludes us, since it involves the collective non-linear dynamics of many particle systems interacting via long-range forces described by the Vlasov equation. As a step towards developing a clearer picture of collisionless self-gravitating relaxation, we analyse the linearized dynamics of isolated one-dimensional systems near thermal equilibrium by expanding their phase-space distribution functions f(x, v) in terms of Hermite functions in the velocity variable, and Legendre functions involving the position variable. This approach produces a picture of phase-space evolution in terms of expansion coefficients, rather than spatial and velocity variables. We obtain equations of motion for the expansion coefficients for both test-particle distributions and self-gravitating linear perturbations of thermal equilibrium. N-body simulations of perturbed equilibria are performed and found to be in excellent agreement with the expansion coefficient approach over a time duration that depends on the size of the expansion series used.

  7. 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.

  8. 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.

  9. 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.

  10. A diverse assemblage of reef corals thriving in a dynamic intertidal reef setting (Bonaparte Archipelago, Kimberley, Australia.

    Directory of Open Access Journals (Sweden)

    Zoe T Richards

    Full Text Available The susceptibility of reef-building corals to climatic anomalies is well documented and a cause of great concern for the future of coral reefs. Reef corals are normally considered to tolerate only a narrow range of climatic conditions with only a small number of species considered heat-tolerant. Occasionally however, corals can be seen thriving in unusually harsh reef settings and these are cause for some optimism about the future of coral reefs. Here we document for the first time a diverse assemblage of 225 species of hard corals occurring in the intertidal zone of the Bonaparte Archipelago, north western Australia. We compare the environmental conditions at our study site (tidal regime, SST and level of turbidity with those experienced at four other more typical tropical reef locations with similar levels of diversity. Physical extremes in the Bonaparte Archipelago include tidal oscillations of up to 8 m, long subaerial exposure times (>3.5 hrs, prolonged exposure to high SST and fluctuating turbidity levels. We conclude the timing of low tide in the coolest parts of the day ameliorates the severity of subaerial exposure, and the combination of strong currents and a naturally high sediment regime helps to offset light and heat stress. The low level of anthropogenic impact and proximity to the Indo-west Pacific centre of diversity are likely to further promote resistance and resilience in this community. This assemblage provides an indication of what corals may have existed in other nearshore locations in the past prior to widespread coastal development, eutrophication, coral predator and disease outbreaks and coral bleaching events. Our results call for a re-evaluation of what conditions are optimal for coral survival, and the Bonaparte intertidal community presents an ideal model system for exploring how species resilience is conferred in the absence of confounding factors such as pollution.

  11. Thermal reaction norms and the scale of temperature variation: latitudinal vulnerability of intertidal nacellid limpets to climate change.

    Directory of Open Access Journals (Sweden)

    Simon A Morley

    Full Text Available The thermal reaction norms of 4 closely related intertidal Nacellid limpets, Antarctic (Nacella concinna, New Zealand (Cellana ornata, Australia (C. tramoserica and Singapore (C. radiata, were compared across environments with different temperature magnitude, variability and predictability, to test their relative vulnerability to different scales of climate warming. Lethal limits were measured alongside a newly developed metric of "duration tenacity", which was tested at different temperatures to calculate the thermal reaction norm of limpet adductor muscle fatigue. Except in C. tramoserica which had a wide optimum range with two break points, duration tenacity did not follow a typical aerobic capacity curve but was best described by a single break point at an optimum temperature. Thermal reaction norms were shifted to warmer temperatures in warmer environments; the optimum temperature for tenacity (T(opt increased from 1.0°C (N. concinna to 14.3°C (C. ornata to 18.0°C (an average for the optimum range of C. tramoserica to 27.6°C (C. radiata. The temperature limits for duration tenacity of the 4 species were most consistently correlated with both maximum sea surface temperature and summer maximum in situ habitat logger temperature. Tropical C. radiata, which lives in the least variable and most predictable environment, generally had the lowest warming tolerance and thermal safety margin (WT and TSM; respectively the thermal buffer of CT(max and T(opt over habitat temperature. However, the two temperate species, C. ornata and C. tramoserica, which live in a variable and seasonally unpredictable microhabitat, had the lowest TSM relative to in situ logger temperature. N. concinna which lives in the most variable, but seasonally predictable microhabitat, generally had the highest TSMs. Intertidal animals live at the highly variable interface between terrestrial and marine biomes and even small changes in the magnitude and predictability of their

  12. Thermal reaction norms and the scale of temperature variation: latitudinal vulnerability of intertidal nacellid limpets to climate change.

    Science.gov (United States)

    Morley, Simon A; Martin, Stephanie M; Day, Robert W; Ericson, Jess; Lai, Chien-Houng; Lamare, Miles; Tan, Koh-Siang; Thorne, Michael A S; Peck, Lloyd S

    2012-01-01

    The thermal reaction norms of 4 closely related intertidal Nacellid limpets, Antarctic (Nacella concinna), New Zealand (Cellana ornata), Australia (C. tramoserica) and Singapore (C. radiata), were compared across environments with different temperature magnitude, variability and predictability, to test their relative vulnerability to different scales of climate warming. Lethal limits were measured alongside a newly developed metric of "duration tenacity", which was tested at different temperatures to calculate the thermal reaction norm of limpet adductor muscle fatigue. Except in C. tramoserica which had a wide optimum range with two break points, duration tenacity did not follow a typical aerobic capacity curve but was best described by a single break point at an optimum temperature. Thermal reaction norms were shifted to warmer temperatures in warmer environments; the optimum temperature for tenacity (T(opt)) increased from 1.0°C (N. concinna) to 14.3°C (C. ornata) to 18.0°C (an average for the optimum range of C. tramoserica) to 27.6°C (C. radiata). The temperature limits for duration tenacity of the 4 species were most consistently correlated with both maximum sea surface temperature and summer maximum in situ habitat logger temperature. Tropical C. radiata, which lives in the least variable and most predictable environment, generally had the lowest warming tolerance and thermal safety margin (WT and TSM; respectively the thermal buffer of CT(max) and T(opt) over habitat temperature). However, the two temperate species, C. ornata and C. tramoserica, which live in a variable and seasonally unpredictable microhabitat, had the lowest TSM relative to in situ logger temperature. N. concinna which lives in the most variable, but seasonally predictable microhabitat, generally had the highest TSMs. Intertidal animals live at the highly variable interface between terrestrial and marine biomes and even small changes in the magnitude and predictability of their

  13. Tropical deforestation alters hummingbird movement patterns

    Science.gov (United States)

    Hadley, Adam S.; Betts, Matthew G.

    2009-01-01

    Reduced pollination success, as a function of habitat loss and fragmentation, appears to be a global phenomenon. Disruption of pollinator movement is one hypothesis put forward to explain this pattern in pollen limitation. However, the small size of pollinators makes them very difficult to track; thus, knowledge of their movements is largely speculative. Using tiny radio transmitters (0.25 g), we translocated a generalist tropical ‘trap-lining’ hummingbird, the green hermit (Phaethornis guy), across agricultural and forested landscapes to test the hypothesis that movement is influenced by patterns of deforestation. Although, we found no difference in homing times between landscape types, return paths were on average 459±144 m (±s.e.) more direct in forested than agricultural landscapes. In addition, movement paths in agricultural landscapes contained 36±4 per cent more forest than the most direct route. Our findings suggest that this species can circumvent agricultural matrix to move among forest patches. Nevertheless, it is clear that movement of even a highly mobile species is strongly influenced by landscape disturbance. Maintaining landscape connectivity with forest corridors may be important for enhancing movement, and thus in facilitating pollen transfer. PMID:19158031

  14. 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

  15. Surface-sediment and hermit-crab contamination by butyltins in southeastern Atlantic estuaries after ban of TBT-based antifouling paints.

    Science.gov (United States)

    Sant'Anna, B S; Santos, D M; Marchi, M R R; Zara, F J; Turra, A

    2014-05-01

    Butyltin (BT) contamination was evaluated in hermit crabs from 25 estuaries and in sediments from 13 of these estuaries along about 2,000 km of the Brazilian coast. BT contamination in hermit crabs ranged from 2.22 to 1,746 ng Sn g(-1) of DBT and 1.32 to 318 ng Sn g(-1) of TBT. In sediment samples, the concentration also varied widely, from 25 to 1,304 ng Sn g(-1) of MBT, from 7 to 158 ng Sn g(-1) of DBT, and from 8 to 565 ng Sn g(-1) of TBT. BTs are still being found in surface sediments and biota of the estuaries after the international and Brazilian bans, showing heterogeneous distribution among and within estuaries. Although hermit crabs were previously tested as an indicator of recent BT contamination, the results indicate the presence of contamination, probably from resuspension of BTs from deeper water of the estuary.

  16. Cylindrical particle manipulation and negative spinning using a nonparaxial Hermite-Gaussian light-sheet beam

    Science.gov (United States)

    Mitri, F. G.

    2016-10-01

    Based on the angular spectrum decomposition method (ASDM), a nonparaxial solution for the Hermite-Gaussian (HG m ) light-sheet beam of any order m is derived. The beam-shape coefficients (BSCs) are expressed in a compact form and computed using the standard Simpson’s rule for numerical integration. Subsequently, the analysis is extended to evaluate the longitudinal and transverse radiation forces as well as the spin torque on an absorptive dielectric cylindrical particle in 2D without any restriction to a specific range of frequencies. The dynamics of the cylindrical particle are also examined based on Newton’s second law of motion. The numerical results show that a Rayleigh or Mie cylindrical particle can be trapped, pulled or propelled in the optical field depending on its initial position in the cross-sectional plane of the HG m light-sheet. Moreover, negative or positive axial spin torques can arise depending on the choice of the non-dimensional size parameter ka (where k is the wavenumber and a is the radius of the cylinder) and the location of the absorptive cylinder in the beam. This means that the HG m light-sheet beam can induce clockwise or anti-clockwise rotations depending on its shift from the center of the cylinder. In addition, individual vortex behavior can arise in the cross-sectional plane of wave propagation. The present analysis presents an analytical model to predict the optical radiation forces and torque induced by a HG m light-sheet beam on an absorptive cylinder for applications in optical light-sheet tweezers, optical micro-machines, particle manipulation and opto-fluidics to name a few areas of research.

  17. 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

  18. 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

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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.

  6. How important are intertidal ecosystems for global biogeochemical cycles? Molecular and isotopic evidence for major outwelling of photo-bleached dissolved organic matter from mangroves.

    Science.gov (United States)

    Dittmar, T.; Cooper, W. T.; Koch, B. P.; Kattner, G.

    2006-05-01

    Organic matter, which is dissolved in low concentrations in the vast waters of the oceans, contains a total amount of carbon similar to atmospheric carbon dioxide. To understand global biogeochemical cycles it is crucial to quantify the sources of marine dissolved organic carbon (DOC). We investigated the impact of mangroves, the dominant intertidal vegetation of the tropics, on marine DOC inventories. Stable carbon- isotopes, ultrahigh-resolution mass spectrometry (FTICRMS), lignin-derived phenols and proton nuclear magnetic resonance spectroscopy showed that mangroves are the main source of terrigenous DOC on the shelf off Northern Brazil. Sunlight efficiently destroyed aromatic molecules during transport offshore, removing about one third of mangrove-derived DOC. The remainder was refractory and may thus be distributed over the oceans. On a global scale, we estimate that mangroves account for more than 10 percent of the terrestrially- derived, refractory DOC transported to the ocean, while they cover less than 0.1 percent of the continents' surface.

  7. [Biology and ecology of the terrestrial hermit crab coenobita scaevola forskål of the Red Sea].

    Science.gov (United States)

    Niggemann, Renate

    1968-06-01

    The terrestrial hermit crab Coenobita scaevola is very common on the coast of the Red Sea. The species depends on the sea for its source of food (wrack-fauna), source of drinking-water and water for moistening gills and abdomen. Only in the supra-litoral zone they find gastropod shells to protect their abdomen against insolation, desiccation and mechanical damage. Coenobita scaevola stays in one place for a long time if good living conditions are available. The time of activity of the juveniles differs from one place to another. Some are diurnal, others are nocturnal. There is no evident relation to the ecological factors. Most of the adults are nocturnal. No Coenobita could be collected in Barber traps. The avoidance of such traps by arthropodes has never been observed before. Coenobita scaevola can live for quite a long time under water of sufficient temperature and salinity. The osmotic regulation of the land-hermit crab differs from that of other shore animals. Coenobita can tolerate a wide range of blood concentrations (25-70‰). It controls the concentration of its blood by selecting water of the appropriate salinity.The static problems of Coenobita are solved by regular movement of the legs and special articulation of the legs.As Coenobita scaevola is a phylogenetically young land animal it carries many inhabitants of marine and terrestrial origin.

  8. Effects of visual and chemical cues on orientation behavior of the Red Sea hermit crab Clibanarius signatus

    Directory of Open Access Journals (Sweden)

    Tarek Gad El-Kareem Ismail

    2012-03-01

    Full Text Available Directional orientation of Clibanarius signatus toward different targets of gastropod shells was studied in a circular arena upon exposure to background seawater, calcium concentrations and predatory odor. Directional orientation was absent when crabs were presented with the white background alone. Each shell was tested in different positions (e.g., anterior, posterior, upside-down, lateral. Adult crabs were tested without their gastropod shells, and orientation varied with concentration and chemical cue. With calcium, orientation increased as concentration increased up to a maximum attraction percentage and then attraction became stable. In the case of predator cues, some individuals swim away from the target toward the opposite direction representing a predator avoidance response. Whenever, the blind hermit crab C. signatus was exposed to a shell target combined with calcium or predator cues, the majority of them stop moving or move in circles around the arena center. The others exhibited uniform orientation distribution. The responsiveness was higher with calcium cues than predator cues. Thus in the absence of vision, individual hermit crabs were able to detect both calcium and predator cues and have different response regarding them.

  9. Boldness in a deep sea hermit crab to simulated tactile predator attacks is unaffected by ocean acidification

    Science.gov (United States)

    Kim, Tae Won; Barry, James P.

    2016-09-01

    Despite rapidly growing interest in the effects of ocean acidification on marine animals, the ability of deep-sea animals to acclimate or adapt to reduced pH conditions has received little attention. Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species because they inhabit relatively stable conditions for nearly all environmental parameters. To explore whether deep-sea hermit crabs ( Pagurus tanneri) can acclimate to ocean acidification over several weeks, we compared behavioral "boldness," measured as time taken to re-emerge from shells after a simulated predatory attack by a toy octopus, under ambient (pH ˜7.6) and expected future (pH ˜7.1) conditions. The boldness measure for crab behavioral responses did not differ between different pH treatments, suggesting that future deep-sea acidification would not influence anti-predatory behavior. However, we did not examine the effects of olfactory cues released by predators that may affect hermit crab behavior and could be influenced by changes in the ocean carbonate system driven by increasing CO2 levels.

  10. Shell occupation by the hermit crab Dardanus insignis (Decapoda, Diogenidae from the north Coast of São Paulo state, Brazil

    Directory of Open Access Journals (Sweden)

    I. F. Frameschi

    Full Text Available Abstract The pattern of shell occupation by the hermit crab Dardanus insignis (Saussure, 1858 from the subtropical region of southeastern coast of Brazil was investigated in the present study. The percentage of shell types that were occupied and the morphometric relationships between hermit crabs and occupied shells were analyzed from monthly collections conducted during two years (from January 1998 to December 1999. Individuals were categorized according to sex and gonadal maturation, weighed and measured with respect to their cephalothoracic shield length (CSL and wet weight (CWW. Shells were measured regarding their aperture width (SAW, dry weight (SDW and internal volume (SIV. A total of 1086 hermit crabs was collected, occupying shells of 11 gastropod species. Olivancillaria urceus (Roding, 1798 was most commonly used by the hermit crab D. insignis, followed by Buccinanops cochlidium (Dillwyn, 1817, and Stramonita haemastoma (Linnaeus, 1767. The highest determination coefficients (r2 > 0.50, p < 0.01 were recorded particularly in the morphometric relationships between CSL vs. CWW and SAW vs. SIV, which are important indication that in this D. insignis population the great majority the animals occupied adequate shells during the two years analysed. The high number of used shell species and relative plasticity in pattern of shell utilization by smaller individuals of D. insignis indicated that occupation is influenced by the shell availability, while larger individuals demonstrated more specialized occupation in Tonna galea (Linnaeus, 1758 shell.

  11. On the velocity space discretization for the Vlasov-Poisson system: comparison between implicit Hermite spectral and Particle-in-Cell methods

    NARCIS (Netherlands)

    E. Camporeale (Enrico); G.L. Delzanno; B.K. Bergen; J.D. Moulton

    2016-01-01

    htmlabstractWe describe a spectral method for the numerical solution of the Vlasov–Poisson system where the velocity space is decomposed by means of an Hermite basis, and the configuration space is discretized via a Fourier decomposition. The novelty of our approach is an implicit time

  12. The anatomy of the king crab Hapalogaster mertensii Brandt, 1850 (Anomura: Paguroidea: Hapalogastridae): new insights into the evolutionary transformation of hermit crabs into king crabs

    NARCIS (Netherlands)

    Keiler, J.; Richter, S.; Wirkner, C.S.

    2015-01-01

    The emergence of king crabs from a hermit crab-like ancestor is one of the most curious events in decapod evolution. King crabs comprise two taxa, Lithodidae and Hapalogastridae, and while lithodids have formed the focus of various anatomical studies, the internal anatomy of hapalogastrids has never

  13. Egg production and shell relationship of the land hermit crab Coenobita scaevola (Anomura: Coenobitidae from Wadi El-Gemal, Red Sea, Egypt

    Directory of Open Access Journals (Sweden)

    Wafaa S. Sallam

    2012-03-01

    Full Text Available The aim of the present study is to characterize the fecundity of the land hermit crab Coenobita scaevola as well as the influence of shell type on fecundity using morphometric relationships. Hermit crabs were collected monthly from January to December 2007 from the protected area of Wadi El-Gemal, at Marsa Alam on the Red Sea, and ovigerous females were selected. Hermit crab wet weight and the gastropod shell weight were recorded. The number of eggs carried by females of several sizes (CL, carapace length, stages of development and egg size were determined. Shells of eight gastropod species were occupied by ovigerous females of C. scaevola. Shells of Nerita undata was the most occupied (65.7%, particularly by individuals falling within the size range 5.0–7.0 mm CL. Only 35 berried females were recorded during May, July and September and the mean fecundity was 679.8 ± 140 eggs. Fecundity was found positively correlated with crab size and shell dimensions. The relationship between fecundity and the internal volume of the occupied shell was ranked as the most correlated. The impact of shell utilization on hermit crab fecundity is discussed.

  14. 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

  15. Hermit crab (Decapoda, Anomura attraction to dead gastropod baits in an infralittoral algae bank

    Directory of Open Access Journals (Sweden)

    Juarez C. B. Pezzuti

    2002-06-01

    Full Text Available Hermit crabs use gastropod shells as shelter and are adapted to follow chemical cues released from tissues of dead or injured gastropods as a way to find new and more adequate shells. The species composition, crab size, shell types adequacy and physical condition were compared between attracted individuals and crabs collected in previous samples. The previous sampling was carried out in five areas before each experiment. Then, five baits of crushed gastropods in nylon net bags were installed in these areas. Three samples were taken at 30min intervals, capturing all crabs within a circle of 60cm diameter. Attraction of hermit crabs was tested for four different gastropod baits to verify specificity of the chemical cues. Clibanarius antillensis, Pagurus brevidactylus and Paguristes tortugae were collected in the study area. Pagurus brevidactylus, the smallest species, turned out to be more attracted than the 2 other species. The results showed that attracted crabs utilized more gastropod shell types than that collected in previous samples, however shell utilization pattern did not differ between them. Attracted animals were slightly smaller (shield length than those collected in the previous samples but did not present significant differences in shell adequacy and condition. The four experimental baits attracted the crabs in similar ways not indicating a specific response from the crabs. The fact that attracted animals were smaller suggested that the attraction to dead gastropods might enable the acquisition of a new and larger shell and, consequently, chains of shell exchange between the attracted crabs.Ermitões utilizam conchas de gastrópodes para abrigo. Conchas novas e mais adequadas podem ser encontradas pelos ermitões pois estes são atraídos por substâncias químicas liberadas pelos tecidos de gastrópodes feridos ou mortos. A adequação, condição e tipo das conchas e a composição de espécies e o tamanho dos ermitões foram

  16. 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.

  17. 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

  18. Multivariate Hermite interpolation on scattered point sets using tensor-product expo-rational B-splines

    Science.gov (United States)

    Dechevsky, Lubomir T.; Bang, Børre; Laksa˚, Arne; Zanaty, Peter

    2011-12-01

    At the Seventh International Conference on Mathematical Methods for Curves and Surfaces, To/nsberg, Norway, in 2008, several new constructions for Hermite interpolation on scattered point sets in domains in Rn,n∈N, combined with smooth convex partition of unity for several general types of partitions of these domains were proposed in [1]. All of these constructions were based on a new type of B-splines, proposed by some of the authors several years earlier: expo-rational B-splines (ERBS) [3]. In the present communication we shall provide more details about one of these constructions: the one for the most general class of domain partitions considered. This construction is based on the use of two separate families of basis functions: one which has all the necessary Hermite interpolation properties, and another which has the necessary properties of a smooth convex partition of unity. The constructions of both of these two bases are well-known; the new part of the construction is the combined use of these bases for the derivation of a new basis which enjoys having all above-said interpolation and unity partition properties simultaneously. In [1] the emphasis was put on the use of radial basis functions in the definitions of the two initial bases in the construction; now we shall put the main emphasis on the case when these bases consist of tensor-product B-splines. This selection provides two useful advantages: (A) it is easier to compute higher-order derivatives while working in Cartesian coordinates; (B) it becomes clear that this construction becomes a far-going extension of tensor-product constructions. We shall provide 3-dimensional visualization of the resulting bivariate bases, using tensor-product ERBS. In the main tensor-product variant, we shall consider also replacement of ERBS with simpler generalized ERBS (GERBS) [2], namely, their simplified polynomial modifications: the Euler Beta-function B-splines (BFBS). One advantage of using BFBS instead of ERBS

  19. 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

  20. Comparative Analysis of Transcriptomes in Rhizophoraceae Provides Insights into the Origin and Adaptive Evolution of Mangrove Plants in Intertidal Environments

    Directory of Open Access Journals (Sweden)

    Wuxia Guo

    2017-05-01

    Full Text Available Mangroves are woody plants that grow at the interface between land and sea in tropical and subtropical latitudes, where they exist in conditions of high salinity, extreme tides, strong winds, high temperatures, and muddy, anaerobic soils. Rhizophoraceae is a key mangrove family, with highly developed morphological and physiological adaptations to extreme conditions. It is an ideal system for the study of the origin and adaptive evolution of mangrove plants. In this study, we characterized and comprehensively compared the transcriptomes of four mangrove species, from all four mangrove genera, as well as their closest terrestrial relative in Rhizophoraceae, using RNA-Seq. We obtained 41,936–48,845 unigenes with N50 values of 982–1,185 bp and 61.42–69.48% annotated for the five species in Rhizophoraceae. Orthology annotations of Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Clusters of Orthologous Groups revealed overall similarities in the transcriptome profiles among the five species, whereas enrichment analysis identified remarkable genomic characteristics that are conserved across the four mangrove species but differ from their terrestrial relative. Based on 1,816 identified orthologs, phylogeny analysis and divergence time estimation revealed a single origin for mangrove species in Rhizophoraceae, which diverged from the terrestrial lineage ~56.4 million years ago (Mya, suggesting that the transgression during the Paleocene–Eocene Thermal Maximum may have been responsible for the entry of the mangrove lineage of Rhizophoraceae into intertidal environments. Evidence showed that the ancestor of Rhizophoraceae may have experienced a whole genome duplication event ~74.6 Mya, which may have increased the adaptability and survival chances of Rhizophoraceae during and following the Cretaceous–Tertiary extinction. The analysis of positive selection identified 10 positively selected genes from the ancestor branch of

  1. A new species of Pagurus (Crustacea: Decapoda: Paguridae, new records and a redescription of hermit crabs from the Mexican Pacific

    Directory of Open Access Journals (Sweden)

    Manuel Ayón-Parente

    2012-09-01

    Full Text Available New records are provided for three species of little-known pagurids. All the material reported was collected by the R/V “El Puma” in the central Gulf of California during the GUAYTEC II cruise. New material is reported for Iridopagurus haigae García-Gómez, 1983, Enallopagurus spinicarpus (Glassell, 1937, and Solenopagurus diomedeae (Faxon, 1893, and these two latter species are redescribed. A new species of hermit crab of the genus Pagurus Fabricius, 1775, is described and illustrated in detail. Among the eastern Pacific species of Pagurus, this new species resembles Pagurus meloi Lemaitre and Cruz Castaño, 2004, P. imarpe Haig, 1974 and P. delsolari Haig, 1974, but differs from these three species in the armature and setation of the chelipeds and second and third pereopods, the shape and armature of the telson, and the number of rows of scales on pereopodal rasp and the presence of a preungual process.

  2. Runge-Kutta and Hermite Collocation for a biological invasion problem modeled by a generalized Fisher equation

    International Nuclear Information System (INIS)

    Athanasakis, I E; Papadopoulou, E P; Saridakis, Y G

    2014-01-01

    Fisher's equation has been widely used to model the biological invasion of single-species communities in homogeneous one dimensional habitats. In this study we develop high order numerical methods to accurately capture the spatiotemporal dynamics of the generalized Fisher equation, a nonlinear reaction-diffusion equation characterized by density dependent non-linear diffusion. Working towards this direction we consider strong stability preserving Runge-Kutta (RK) temporal discretization schemes coupled with the Hermite cubic Collocation (HC) spatial discretization method. We investigate their convergence and stability properties to reveal efficient HC-RK pairs for the numerical treatment of the generalized Fisher equation. The Hadamard product is used to characterize the collocation discretized non linear equation terms as a first step for the treatment of generalized systems of relevant equations. Numerical experimentation is included to demonstrate the performance of the methods

  3. Reality of Energy Spectra in Multi-dimensional Hamiltonians Having Pseudo Hermiticity with Respect to the Exchange Operator

    International Nuclear Information System (INIS)

    Nanayakkara, Asiri

    2005-01-01

    The pseudo Hermiticity with respect to the exchange operators of N-D complex Hamiltonians is investigated. It is shown that if an N-D Hamiltonian is pseudo Hermitian and any eigenfunction of it retains π α T symmetry then the corresponding eigen value is real, where π α is an exchange operator with respect to the permutation α of coordinates and T is the time reversal operator. We construct a special class of N-D pseudo Hermitian Hamiltonians with respect to exchange operators from both N/2-D and N-D general complex Hamiltonians. Examples are presented for Hamiltonians with πT symmetry (π:x↔y, p x ↔p y ) and the reality of these systems are investigated.

  4. Generalized treatment of point reactor kinetics driven by random reactivity fluctuations via the Wiener-Hermite functional method

    International Nuclear Information System (INIS)

    Behringer, K.

    1991-02-01

    In a recent paper by Behringer et al. (1990), the Wiener-Hermite Functional (WHF) method has been applied to point reactor kinetics excited by Gaussian random reactivity noise under stationary conditions, in order to calculate the neutron steady-state value and the neutron power spectral density (PSD) in a second-order (WHF-2) approximation. For simplicity, delayed neutrons and any feedback effects have been disregarded. The present study is a straightforward continuation of the previous one, treating the problem more generally by including any number of delayed neutron groups. For the case of white reactivity noise, the accuracy of the approach is determined by comparison with the exact solution available from the Fokker-Planck method. In the numerical comparisons, the first-oder (WHF-1) approximation of the PSD is also considered. (author) 4 figs., 10 refs

  5. Application of the Wiener-Hermite functional method to point reactor kinetics driven by random reactivity fluctuations

    International Nuclear Information System (INIS)

    Behringer, K.; Pineyro, J.; Mennig, J.

    1990-06-01

    The Wiener-Hermite functional (WHF) method has been applied to the point reactor kinetic equation excited by Gaussian random reactivity noise under stationary conditions. Delayed neutrons and any feedback effects are disregarded. The neutron steady-state value and the power spectral density (PSD) of the neutron flux have been calculated in a second order (WHF-2) approximation. Two cases are considered: in the first case, the noise source is low-pass white noise. In both cases the WHF-2 approximation of the neutron PSDs leads to relatively simple analytical expressions. The accuracy of the approach is determined by comparison with exact solutions of the problem. The investigations show that the WHF method is a powerful approximative tool for studying the nonlinear effects in the stochastic differential equation. (author) 5 figs., 29 refs

  6. The use of Gauss-Hermite quadrature in the determination of the molecular weight distribution of linear polymers by rheometry

    Directory of Open Access Journals (Sweden)

    T. M. Farias

    2013-12-01

    Full Text Available The molecular weight distribution (MWD and its parameters are of the fundamental importance in the characterization of polymers. Therefore, the development of techniques for faster MWD determination is a relevant issue. This paper aims at implementing one of the relaxation models from double reptation theory proposed in the literature and analyzing the numeric strategy for the evaluation of the integrals appearing in the relaxation model. The inverse problem, i.e., the determination of the MWD from rheological data using a specified relaxation model and an imposed distribution function was approximated. Concerning the numerical strategy for the evaluation of the integrals appearing in the relaxation models, the use of Gauss-Hermite quadrature using a new change of variables was proposed. In the test of samples of polyethylene with polydispersities less than 10, the application of this methodology led to MWD curves which provided a good fit of the experimental SEC data.

  7. Self-focusing of a Hermite-cosh Gaussian laser beam in a magnetoplasma with ramp density profile

    International Nuclear Information System (INIS)

    Nanda, Vikas; Kant, Niti; Wani, Manzoor Ahmad

    2013-01-01

    The early and strong self-focusing of a Hermite-cosh-Gaussian laser beam in magnetoplasma in the presence of density ramp has been observed. Focusing and de-focusing nature of the Hermite-cosh-Gaussian laser beam with decentered parameter and magnetic field has been studied, and strong self-focusing is reported. It is investigated that decentered parameter 'b' plays a significant role for the self-focusing of the laser beam and is very sensitive as in case of extraordinary mode. For mode indices, m = 0, 1, 2, and b = 4.00, 3.14, and 2.05, strong self-focusing is observed. Similarly in case of ordinary mode, for m = 0, 1, 2 and b = 4.00, 3.14, 2.049, respectively, strong self-focusing is reported. Further, it is seen that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For mode indices m = 0, 1, and 2, diffraction term becomes more dominant over nonlinear term for decentered parameter b=0. For selective higher values of decentered parameter in case of mode indices m=0, 1, and 2, self-focusing effect becomes strong for extraordinary mode. Also increase in the value of magnetic field enhances the self-focusing ability of the laser beam, which is very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers

  8. Self-focusing of a Hermite-cosh Gaussian laser beam in a magnetoplasma with ramp density profile

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, Vikas; Kant, Niti; Wani, Manzoor Ahmad [Department of Physics, Lovely Professional University, Phagwara 144411, Punjab (India)

    2013-11-15

    The early and strong self-focusing of a Hermite-cosh-Gaussian laser beam in magnetoplasma in the presence of density ramp has been observed. Focusing and de-focusing nature of the Hermite-cosh-Gaussian laser beam with decentered parameter and magnetic field has been studied, and strong self-focusing is reported. It is investigated that decentered parameter 'b' plays a significant role for the self-focusing of the laser beam and is very sensitive as in case of extraordinary mode. For mode indices, m = 0, 1, 2, and b = 4.00, 3.14, and 2.05, strong self-focusing is observed. Similarly in case of ordinary mode, for m = 0, 1, 2 and b = 4.00, 3.14, 2.049, respectively, strong self-focusing is reported. Further, it is seen that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For mode indices m = 0, 1, and 2, diffraction term becomes more dominant over nonlinear term for decentered parameter b=0. For selective higher values of decentered parameter in case of mode indices m=0, 1, and 2, self-focusing effect becomes strong for extraordinary mode. Also increase in the value of magnetic field enhances the self-focusing ability of the laser beam, which is very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers.

  9. Morphology and histochemistry of the aesthetasc-associated epidermal glands in terrestrial hermit crabs of the genus Coenobita (Decapoda: Paguroidea.

    Directory of Open Access Journals (Sweden)

    Oksana Tuchina

    Full Text Available Crustaceans have successfully adapted to a variety of environments including fresh- and saltwater as well as land. Transition from an aquatic to a terrestrial lifestyle required adaptations of the sensory equipment of an animal, particularly in olfaction, where the stimulus itself changes from hydrophilic to mainly hydrophobic, air-borne molecules. Hermit crabs Coenobita spp. (Anomura, Coenobitidae have adapted to a fully terrestrial lifestyle as adults and have been shown to rely on olfaction in order to detect distant food items. We observed that the specialized olfactory sensilla in Coenobita, named aesthetascs, are immersed in a layer of mucous-like substance. We hypothesized that the mucous is produced by antennal glands and affects functioning of the aesthetascs. Using various microscopic and histochemical techniques we proved that the mucous is produced by aesthetasc-associated epidermal glands, which we consider to be modified rosette-type aesthetasc tegumental glands known from aquatic decapods. These epidermal glands in Coenobita are multicellular exocrine organs of the recto-canal type with tubulo-acinar arrangement of the secretory cells. Two distinct populations of secretory cells were clearly distinguishable with light and electron microscopy. At least part of the secretory cells contains specific enzymes, CUB-serine proteases, which are likely to be secreted on the surface of the aesthetasc pad and take part in antimicrobial defense. Proteomic analysis of the glandular tissue corroborates the idea that the secretions of the aesthetasc-associated epidermal glands are involved in immune responses. We propose that the mucous covering the aesthetascs in Coenobita takes part in antimicrobial defense and at the same time provides the moisture essential for odor perception in terrestrial hermit crabs. We conclude that the morphological modifications of the aesthetasc-associated epidermal glands as well as the functional characteristics

  10. Shell utilization pattern of the hermit crab Clibanarius vittatus (Crustacea, Anomura in an estuary at São Vicente, State of São Paulo, Brazil Padrão de utilização de conchas do ermitão Clibanarius vittatus (Crustacea, Anomura, no Estuário de São Vicente, Estado de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Bruno S. Sant'Anna

    2006-06-01

    Full Text Available We evaluated the gastropod shell utilization pattern of the hermit crab Clibanarius vittatus (Bosc, 1802 at Pescadores Beach in São Vicente, State of São Paulo, Brazil. Specimens were collected monthly from May 2001 through April 2003, in the intertidal zone at low tide. The crabs were weighed and their carapace shield length measured. All gastropod shells were identified and had their shell biometric parameters (total length and aperture length measured (mm and weighed (g. A total of 2,344 hermit crabs (644 males, 1,594 females, 45 ovigerous females and 61 individuals in intersex, using 13 species of gastropod shells, were collected. Stramonita haemastoma (Linnaeus, 1767, Cymatium parthenopeum (Von Salis, 1793 and Achatina fulica (Bowdich, 1822 comprised over 98% of all the shells. Male and intersex crabs were significantly larger than the females. This size difference strongly influenced the shell utilization pattern, principally in A. fulica, which has the largest shell size, that was only used by males and intersexual individuals of C. vittatus. Cymatium parthenopeum was the only shell species that showed a high determinant coefficient in all the biometric correlations evaluated. The high abundance of S. haemastoma shells and a strong correlation between crab size and shell aperture length established by a significant determination coefficient, indicated that C. vittatus uses this species as the principal resource for shell occupation at Pescadores Beach.O objetivo do presente estudo foi avaliar a utilização de conchas de gastrópodes por Clibanarius vittatus (Bosc, 1802, na Praia dos Pescadores, em São Vicente (SP, Brasil. Foram realizadas amostras mensais no período de maio de 2001 a abril de 2003, na região intertidal durante a maré baixa. Todos os animais foram pesados e tiveram o comprimento de seu escudo cefalotorácico mensurados, suas conchas identificadas e medidas quanto ao comprimento (mm, abertura (mm e peso (g

  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. Tropical Soil Chemistry

    DEFF Research Database (Denmark)

    Borggaard, Ole K.

    and environmental protection. Tropical Soil Chemistry by Ole K. Borggaard provides an overview of the composition, occurrence, properties, processes, formation, and environmental vulnerability of various tropical soil types (using American Soil Taxonomy for classification). The processes and the external factors...... soil chemical issues are also presented to assess when, why, and how tropical soils differ from soils in other regions. This knowledge can help agricultural specialists in the tropics establish sustainable crop production. Readers are assumed to be familiar with basic chemistry, physics...

  14. 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.

  15. 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.

  16. 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.

  17. Neglected tropical diseases

    Directory of Open Access Journals (Sweden)

    David Molyneux

    2013-08-01

    Full Text Available Seventeen neglected tropical diseases (NTDs have been identified by the World Health Organization (WHO. It is estimated that over 1 billion people are infected with NTDs, with a further 1 billion at risk. The majority of NTDs occur in the tropics and sub-tropics and have particular characteristics in common.

  18. Tropical Freshwater Biology

    African Journals Online (AJOL)

    Tropical Freshwater Biology promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater ...

  19. Quality maintenance Tropical Plants

    Directory of Open Access Journals (Sweden)

    Gláucia Moraes Dias

    2016-11-01

    Full Text Available The climatic characteristics of the country favor the cultivation of tropical flowers. The continued expansion of this market is due the beauty, exoticit nature and postharvest longevity of flower. However, little is known about the postharvest of tropical plants. Therefore, this paper provides information on harvest, handling and storage of cut tropical plantspostharvest, storage temperature, conditioning solution.

  20. Spatial distribution and shell utilization in three sympatric hermit crabs at non-consolidated sublittoral of estuarine-bay complex in São Vicente, São Paulo, Brazil

    OpenAIRE

    Sant'Anna, Bruno S. [UNESP; Zangrande, Cilene M. [UNESP; Reigada, Álvaro L.D. [UNESP; Severino-Rodrigues, Evandro

    2006-01-01

    The objective of the present study was to characterize the spatial distribution and shell utilization of three hermit crab species in the estuarine-bay complex of São Vicente, São Paulo State, Brazil. Monthly samples were done throughout two years, in the non-consolidated sub-littoral at the estuarine-bay complex. The environmental factors, such as temperature, salinity and depth, were measured every month. The three hermit crab species, Clibanarius vittatus, Loxopagurus loxochelis and Isoche...

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

    Science.gov (United States)

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

    2008-11-01

    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 presence and abundance of molluscs (gastropods and bivalves). To explain observed differences between molluscan assemblages in seagrass and bare patches, some aspects of the feeding habitat (top-5 mm of the sediment) and of food (organic materials) of molluscs were examined. The novelty of this study is that phytopigments were measured and identified to assess source and level of decay (freshness) of organic material in the sediment and to study their importance as an explanatory variable for the distribution of molluscs. Over an area of 36 km 2 of intertidal flats, at 12 sites, paired comparisons were made between seagrass-covered and nearby bare patches. Within seagrass meadows, dry mass of living seagrass was large and amounted to 180 ±10 g AFDM m - 2 (range 75-240). Containing twice the amount of silt per unit dry sediment mass, seagrass sediments were muddier than bare areas; the relative amount of organic material was also larger. The total number of species of bivalves and gastropods amounted to 27, 14 of which were found only in seagrass areas, 4 only in bare and 9 in both types of habitat. Among the three numerically most abundant species, the bivalves Anadara senilis, Dosinia hepatica and Loripes lacteus, the first was numerically most abundant in bare and the other two in seagrass-covered areas. Bare intertidal areas had greater mean total biomass of molluscs (80.5 g AFDM m - 2 ) than seagrass meadows (30.0 g AFDM m - 2 ). In both habitats, the bulk of the biomass was made up by A. senilis. Excluding this species, bare mudflats contained on average only 3.1 g AFDM m - 2 and seagrass meadows 6.9 g AFDM m - 2 . As compared to previous surveys in 1980-1986, the

  2. An integrative approach-using field and laboratory data to characterize shell utilization and selection pattern by the hermit crab Pagurus criniticornis (Paguridae from Anchieta Island, Brazil

    Directory of Open Access Journals (Sweden)

    Fernando L. Mantelatto

    Full Text Available Abstract The aim of this study was to characterize the pattern of gastropod shell occupation in the field and selection of shell size and type under laboratory conditions by the hermit crab Pagurus criniticornis (Dana, 1852, inhabiting the infralittoral area of Anchieta Island, São Paulo, Brazil. Hermit crabs were obtained monthly during 1999 by SCUBA diving. For experiments under laboratory conditions, samplings were performed in 2002. The hermit crabs occupied 16 species of gastropods shells. Cerithium atratum (Born, 1778 was the most occupied shell (89.31%, followed by Morula nodulosa (4.73% (Adams, 1845. No difference was observed in the pattern of occupation between males and females. The equations that best demonstrated the relationship between hermit crabs and their shells were those that involved Shell Wet Weight (SWW and Shell Internal Volume (SIV. The laboratory experiments were in accordance to the pattern of occupation observed in the field; the mean value of SAI (Shell Adequacy Index recorded to the population studied was 1.13 with a trend to increase this value in the last size classes. The results obtained corroborate with the hypothesis of the occupation process of shells governed not only by availability of shells, but also by its architecture. In addition, the shell stock in the area is one another important condition related to the exhibited pattern of shell occupation by P. criniticornis, and allows the stable coexistence among the island assemblage. The pattern of occupation observed promotes a high reproductive profile for the population studied, maximizing the populational growth.

  3. New operator-ordering identities and associative integration formulas of two-variable Hermite polynomials for constructing non-Gaussian states

    International Nuclear Information System (INIS)

    Fan Hong-Yi; Wang Zhen

    2014-01-01

    For directly normalizing the photon non-Gaussian states (e.g., photon added and subtracted squeezed states), we use the method of integration within an ordered product (IWOP) of operators to derive some new bosonic operator-ordering identities. We also derive some new integration transformation formulas about one- and two-variable Hermite polynomials in complex function space. These operator identities and associative integration formulas provide much convenience for constructing non-Gaussian states in quantum engineering. (general)

  4. 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

  5. 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

  6. Decoupled scheme based on the Hermite expansion to construct lattice Boltzmann models for the compressible Navier-Stokes equations with arbitrary specific heat ratio.

    Science.gov (United States)

    Hu, Kainan; Zhang, Hongwu; Geng, Shaojuan

    2016-10-01

    A decoupled scheme based on the Hermite expansion to construct lattice Boltzmann models for the compressible Navier-Stokes equations with arbitrary specific heat ratio is proposed. The local equilibrium distribution function including the rotational velocity of particle is decoupled into two parts, i.e., the local equilibrium distribution function of the translational velocity of particle and that of the rotational velocity of particle. From these two local equilibrium functions, two lattice Boltzmann models are derived via the Hermite expansion, namely one is in relation to the translational velocity and the other is connected with the rotational velocity. Accordingly, the distribution function is also decoupled. After this, the evolution equation is decoupled into the evolution equation of the translational velocity and that of the rotational velocity. The two evolution equations evolve separately. The lattice Boltzmann models used in the scheme proposed by this work are constructed via the Hermite expansion, so it is easy to construct new schemes of higher-order accuracy. To validate the proposed scheme, a one-dimensional shock tube simulation is performed. The numerical results agree with the analytical solutions very well.

  7. 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

  8. 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

  9. 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,

  10. 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,

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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.

  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. 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.

  1. 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

  2. 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...

  3. 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...

  4. 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.

  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. 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

  9. Checklist of fossil decapod crustaceans from tropical America. Part I: Anomura and Brachyura

    Directory of Open Access Journals (Sweden)

    Javier Luque

    2017-10-01

    Full Text Available Abstract Our knowledge of fossil crustaceans from the tropics has increased considerably during recent decades, thanks to novel findings and the re-examination of museum specimens. However, several previous records have been misidentified, numerous museum specimens have never been reported, and many new discoveries are yet to be published. Here, we present a detailed, up-to-date, and revised checklist for every marine, terrestrial, or freshwater fossil decapod crustacean occurrence from tropical America known to us, including their age, geographic occurrences, and related literature. We recognize the occurrence of at least 32 superfamilies, 69 families, 190 genera, and 415 species of brachyurans (‘true’ crabs, and anomurans (‘false’ crabs, hermit crabs, squat lobsters, and allies, several of them previously unknown. The checklist comprises records from three main geographic regions: 1 northern South America (Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela; 2 Central America and southern North America (Belize, Costa Rica, Honduras, Panama, Mexico, southern and central Florida; and 3 the Caribbean Islands + Bermuda (Anguilla, Antigua, Aruba, Bahamas, Barbados, Bermuda, Bonaire, Cuba, Curaçao, Dominican Republic, The Grenadines, Haiti, Jamaica, Puerto Rico, Saint Bartélemy, Saint Martin, Trinidad. Previous findings, new occurrences, and the revised systematic placement for several problematic/misidentified records, indicate that the fossil record of anomurans and brachyurans in tropical America is more diverse than previously envisioned, with a considerable degree of endemism at the genus- and species-levels.

  10. Modified Hermite Pulse-Based Wideband Communication for High-Speed Data Transfer in Wireless Sensor Applications

    Directory of Open Access Journals (Sweden)

    Kushal P. Pradhan

    2017-12-01

    Full Text Available With technological advances in the field of communication, the need for reliable high-speed data transfer is increasing. The deployment of large number of wireless sensors for remote monitoring and control and streaming of high definition video, voice and image data, etc. are imposing a challenge to the existing network bandwidth allocation for reliable communication. Two novel schemes for ultra-wide band (UWB communication technology have been proposed in this paper with the key objective of intensifying the data rate by taking advantage of the orthogonal properties of the modified Hermite pulse (MHP. In the first scheme, a composite pulse is transmitted and in the second scheme, a sequence of multi-order orthogonal pulses is transmitted in the place of a single UWB pulse. The MHP pulses exhibit a mutually orthogonal property between different ordered pulses and due to this property, simultaneous transmission is achieved without collision in the UWB system, resulting in an increase in transmission capacity or improved bit error rate. The proposed schemes for enhanced data rate will offer high volume data monitoring, assessment, and control of wireless devices without overburdening the network bandwidth and pave the way for new platforms for future high-speed wireless sensor applications.

  11. An Extreme Learning Machine Based on the Mixed Kernel Function of Triangular Kernel and Generalized Hermite Dirichlet Kernel

    Directory of Open Access Journals (Sweden)

    Senyue Zhang

    2016-01-01

    Full Text Available According to the characteristics that the kernel function of extreme learning machine (ELM and its performance have a strong correlation, a novel extreme learning machine based on a generalized triangle Hermitian kernel function was proposed in this paper. First, the generalized triangle Hermitian kernel function was constructed by using the product of triangular kernel and generalized Hermite Dirichlet kernel, and the proposed kernel function was proved as a valid kernel function of extreme learning machine. Then, the learning methodology of the extreme learning machine based on the proposed kernel function was presented. The biggest advantage of the proposed kernel is its kernel parameter values only chosen in the natural numbers, which thus can greatly shorten the computational time of parameter optimization and retain more of its sample data structure information. Experiments were performed on a number of binary classification, multiclassification, and regression datasets from the UCI benchmark repository. The experiment results demonstrated that the robustness and generalization performance of the proposed method are outperformed compared to other extreme learning machines with different kernels. Furthermore, the learning speed of proposed method is faster than support vector machine (SVM methods.

  12. Overtone-based pitch selection in hermit thrush song: unexpected convergence with scale construction in human music.

    Science.gov (United States)

    Doolittle, Emily L; Gingras, Bruno; Endres, Dominik M; Fitch, W Tecumseh

    2014-11-18

    Many human musical scales, including the diatonic major scale prevalent in Western music, are built partially or entirely from intervals (ratios between adjacent frequencies) corresponding to small-integer proportions drawn from the harmonic series. Scientists have long debated the extent to which principles of scale generation in human music are biologically or culturally determined. Data from animal "song" may provide new insights into this discussion. Here, by examining pitch relationships using both a simple linear regression model and a Bayesian generative model, we show that most songs of the hermit thrush (Catharus guttatus) favor simple frequency ratios derived from the harmonic (or overtone) series. Furthermore, we show that this frequency selection results not from physical constraints governing peripheral production mechanisms but from active selection at a central level. These data provide the most rigorous empirical evidence to date of a bird song that makes use of the same mathematical principles that underlie Western and many non-Western musical scales, demonstrating surprising convergence between human and animal "song cultures." Although there is no evidence that the songs of most bird species follow the overtone series, our findings add to a small but growing body of research showing that a preference for small-integer frequency ratios is not unique to humans. These findings thus have important implications for current debates about the origins of human musical systems and may call for a reevaluation of existing theories of musical consonance based on specific human vocal characteristics.

  13. The CFS-PML for 2D Auxiliary Differential Equation FDTD Method Using Associated Hermite Orthogonal Functions

    Directory of Open Access Journals (Sweden)

    Feng Jiang

    2017-01-01

    Full Text Available The complex frequency shifted (CFS perfectly matched layer (PML is proposed for the two-dimensional auxiliary differential equation (ADE finite-difference time-domain (FDTD method combined with Associated Hermite (AH orthogonal functions. According to the property of constitutive parameters of CFS-PML (CPML absorbing boundary conditions (ABCs, the auxiliary differential variables are introduced. And one relationship between field components and auxiliary differential variables is derived. Substituting auxiliary differential variables into CPML ABCs, the other relationship between field components and auxiliary differential variables is derived. Then the matrix equations are obtained, which can be unified with Berenger’s PML (BPML and free space. The electric field expansion coefficients can thus be obtained, respectively. In order to validate the efficiency of the proposed method, one example of wave propagation in two-dimensional free space is calculated using BPML, UPML, and CPML. Moreover, the absorbing effectiveness of the BPML, UPML, and CPML is discussed in a two-dimensional (2D case, and the numerical simulations verify the accuracy and efficiency of the proposed method.

  14. Comparing the strength of behavioural plasticity and consistency across situations: animal personalities in the hermit crab Pagurus bernhardus.

    Science.gov (United States)

    Briffa, Mark; Rundle, Simon D; Fryer, Adam

    2008-06-07

    Many phenotypic traits show plasticity but behaviour is often considered the 'most plastic' aspect of phenotype as it is likely to show the quickest response to temporal changes in conditions or 'situation'. However, it has also been noted that constraints on sensory acuity, cognitive structure and physiological capacities place limits on behavioural plasticity. Such limits to plasticity may generate consistent differences in behaviour between individuals from the same population. It has recently been suggested that these consistent differences in individual behaviour may be adaptive and the term 'animal personalities' has been used to describe them. In many cases, however, a degree of both behavioural plasticity and relative consistency is probable. To understand the possible functions of animal personalities, it is necessary to determine the relative strength of each tendency and this may be achieved by comparison of statistical effect sizes for tests of difference and concordance. Here, we describe a new statistical framework for making such comparisons and investigate cross-situational plasticity and consistency in the duration of startle responses in the European hermit crab Pagurus bernhardus, in the field and the laboratory. The effect sizes of tests for behavioural consistency were greater than for tests of behavioural plasticity, indicating for the first time the presence of animal personalities in a crustacean model.

  15. 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...

  16. 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

  17. 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...

  18. Old tropical botanical collections

    DEFF Research Database (Denmark)

    Friis, Ib

    2017-01-01

    The early history of botanical collections is reviewed, with particular emphasis on old collections from the tropics. The information available about older and newer botanical collections from the tropics was much improved after World War Two, including better lists of validly published names, more...

  19. Tropical Veterinarian: Submissions

    African Journals Online (AJOL)

    Author Guidelines. 2012 Author Guidelines: Instructions to Authors: TROPICAL VETERINARIAN welcomes original work on all aspects of veterinary science as practiced in the Tropics, including livestock production and management, animal disease (domestic and wild), various aspects of preventive medicine and public ...

  20. Tropical Cyclone Propagation

    National Research Council Canada - National Science Library

    Gray, William

    1994-01-01

    This paper discusses the question of tropical cyclone propagation or why the average tropical cyclone moves 1-2 m/s faster and usually 10-20 deg to the left of its surrounding (or 5-7 deg radius) deep layer (850-300 mb) steering current...

  1. Computing Tropical Varieties

    DEFF Research Database (Denmark)

    Speyer, D.; Jensen, Anders Nedergaard; Bogart, T.

    2005-01-01

    The tropical variety of a d-dimensional prime ideal in a polynomial ring with complex coefficients is a pure d-dimensional polyhedral fan. This fan is shown to be connected in codimension one. We present algorithmic tools for computing the tropical variety, and we discuss our implementation...

  2. Introduction to tropical geometry

    CERN Document Server

    Maclagan, Diane

    2015-01-01

    Tropical geometry is a combinatorial shadow of algebraic geometry, offering new polyhedral tools to compute invariants of algebraic varieties. It is based on tropical algebra, where the sum of two numbers is their minimum and the product is their sum. This turns polynomials into piecewise-linear functions, and their zero sets into polyhedral complexes. These tropical varieties retain a surprising amount of information about their classical counterparts. Tropical geometry is a young subject that has undergone a rapid development since the beginning of the 21st century. While establishing itself as an area in its own right, deep connections have been made to many branches of pure and applied mathematics. This book offers a self-contained introduction to tropical geometry, suitable as a course text for beginning graduate students. Proofs are provided for the main results, such as the Fundamental Theorem and the Structure Theorem. Numerous examples and explicit computations illustrate the main concepts. Each of t...

  3. 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.

  4. 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.

  5. 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.

  6. Biocenosis de Bivalvia y Polyplacophora del intermareal rocoso en playa Tlacopanocha, Acapulco, Guerrero, México Polyplacophora and Bivalvia biocenosis at rocky intertidal Tlacopanocha beach, Acapulco, Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    Lizeth Galeana-Rebolledo

    2012-11-01

    Full Text Available El Estado de Guerrero, México, tiene regiones marinas prioritarias para la conservación de su biodiversidad y la información acerca de la diversidad de moluscos es escasa, por lo que es necesario realizar inventarios de especies, estudios de ecología de poblaciones y comunidades. Este estudio se efectuó en el intermareal rocoso de la playa Tlacopanocha. Los objetivos fueron: determinar la riqueza, densidad y diversidad de especies; analizar la composición de especies y estructura de tallas. El área de muestreo fue de 10 m² y la unidad de muestreó fue de 1 m². Se identificaron 35 especies, de las cuales tres son nuevos registros para el intermareal rocoso de Guerrero: las familias mejor representadas en riqueza de especies fueron Ischnochitonidae y Arcidae, y en abundancia Chitonidae y Chamidae; la densidad fue de 31,60 ind m-2. Polyplacophora presentó 42,9% de especies dominantes y Bivalvia 19,0%. Chama corallina presentó la mayor talla en longitud y Chama sordida en ancho. La riqueza de especies de moluscos registrada se considera alta y corresponde a lo esperado para un sustrato rocoso en zona tropical. Polyplacophora presentó alta composición de especies, que podría ser resultado de la adaptación de los organismos a las condiciones dinámicas del intermareal rocoso. Los nuevos registros indican la importancia de los inventarios de especies y también del conocimiento de las poblaciones y comunidades de la fauna marina de Guerrero.The State of Guerrero, Mexico, has priority marine areas for conservation of its biodiversity, but information concerning diversity of mollusks is limited, so it is convenient to carry out species inventories, studies of populations and community ecology. This study was conducted in the intertidal rocky beach Tlacopanocha. The objectives were to determine richness, density and species diversity, analyze the species composition and size structure. The sampling area was 10 m² and the sampling unit was

  7. 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....

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. Central projections of antennular chemosensory and mechanosensory afferents in the brain of the terrestrial hermit crab (Coenobita clypeatus; Coenobitidae, Anomura)

    Science.gov (United States)

    Tuchina, Oksana; Koczan, Stefan; Harzsch, Steffen; Rybak, Jürgen; Wolff, Gabriella; Strausfeld, Nicholas J.; Hansson, Bill S.

    2015-01-01

    The Coenobitidae (Decapoda, Anomura, Paguroidea) is a taxon of hermit crabs that includes two genera with a fully terrestrial life style as adults. Previous studies have shown that Coenobitidae have evolved a sense of spatial odor localization that is behaviorally highly relevant. Here, we examined the central olfactory pathway of these animals by analyzing central projections of the antennular nerve of Coenobita clypeatus, combining backfilling of the nerve with dextran-coupled dye, Golgi impregnations and three-dimensional reconstruction of the primary olfactory center, the antennular lobe. The principal pattern of putative olfactory sensory afferents in C. clypeatus is in many aspects similar to what have been established for aquatic decapod crustaceans, such as the spiny lobster Panulirus argus. However, there are also obvious differences that may, or may not represent adaptations related to a terrestrial lifestyle. In C. clypeatus, the antennular lobe dominates the deutocerebrum, having more than one thousand allantoid-shaped subunits. We observed two distinct patterns of sensory neuron innervation: putative olfactory afferents from the aesthetascs either supply the cap/subcap region of the subunits or they extend through its full depth. Our data also demonstrate that any one sensory axon can supply input to several subunits. Putative chemosensory (non-aesthetasc) and mechanosensory axons represent a different pathway and innervate the lateral and median antennular neuropils. Hence, we suggest that the chemosensory input in C. clypeatus might be represented via a dual pathway: aesthetascs target the antennular lobe, and bimodal sensilla target the lateral antennular neuropil and median antennular neuropil. The present data is compared to related findings in other decapod crustaceans. PMID:26236202

  16. Enhanced relativistic self-focusing of Hermite-cosh-Gaussian laser beam in plasma under density transition

    International Nuclear Information System (INIS)

    Nanda, Vikas; Kant, Niti

    2014-01-01

    Enhanced and early relativistic self-focusing of Hermite-cosh-Gaussian (HChG) beam in the plasmas under density transition has been investigated theoretically using Wentzel-Kramers-Brillouin and paraxial ray approximation for mode indices m=0, 1, and 2. The variation of beam width parameter with normalized propagation distance for m=0, 1, and 2 is reported, and it is observed that strong self-focusing occurs as the HChG beam propagates deeper inside the nonlinear medium as spot size shrinks due to highly dense plasmas and the results are presented graphically. A comparative study between self-focusing of HChG beam in the presence and absence of plasmas density transition is reported. The dependency of beam width parameter on the normalized propagation distance for different values of decentered parameter “b” has also been presented graphically. For m=0 and 1, strong self-focusing is reported for b=1.8, and for m=2 and b=1.8, beam gets diffracted. The results obtained indicate the dependency of the self-focusing of the HChG beam on the selected values of decentered parameter. Moreover, proper selection of decentered parameter results strong self-focusing of HChG beam. Stronger self-focusing of laser beam is observed due to the presence of plasma density transition which might be very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, etc

  17. Enhanced relativistic self-focusing of Hermite-cosh-Gaussian laser beam in plasma under density transition

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, Vikas; Kant, Niti, E-mail: nitikant@yahoo.com [Department of Physics, Lovely Professional University, Phagwara 144411, Punjab (India)

    2014-04-15

    Enhanced and early relativistic self-focusing of Hermite-cosh-Gaussian (HChG) beam in the plasmas under density transition has been investigated theoretically using Wentzel-Kramers-Brillouin and paraxial ray approximation for mode indices m=0, 1, and 2. The variation of beam width parameter with normalized propagation distance for m=0, 1, and 2 is reported, and it is observed that strong self-focusing occurs as the HChG beam propagates deeper inside the nonlinear medium as spot size shrinks due to highly dense plasmas and the results are presented graphically. A comparative study between self-focusing of HChG beam in the presence and absence of plasmas density transition is reported. The dependency of beam width parameter on the normalized propagation distance for different values of decentered parameter “b” has also been presented graphically. For m=0 and 1, strong self-focusing is reported for b=1.8, and for m=2 and b=1.8, beam gets diffracted. The results obtained indicate the dependency of the self-focusing of the HChG beam on the selected values of decentered parameter. Moreover, proper selection of decentered parameter results strong self-focusing of HChG beam. Stronger self-focusing of laser beam is observed due to the presence of plasma density transition which might be very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, etc.

  18. Nectar robbery by a hermit hummingbird: association to floral phenotype and its influence on flowers and network structure.

    Science.gov (United States)

    Maruyama, Pietro Kiyoshi; Vizentin-Bugoni, Jeferson; Dalsgaard, Bo; Sazima, Ivan; Sazima, Marlies

    2015-07-01

    Interactions between flowers and their visitors span the spectrum from mutualism to antagonism. The literature is rich in studies focusing on mutualism, but nectar robbery has mostly been investigated using phytocentric approaches focused on only a few plant species. To fill this gap, we studied the interactions between a nectar-robbing hermit hummingbird, Phaethornis ruber, and the array of flowers it visits. First, based on a literature review of the interactions involving P. ruber, we characterized the association of floral larceny to floral phenotype. We then experimentally examined the effects of nectar robbing on nectar standing crop and number of visits of the pollinators to the flowers of Canna paniculata. Finally, we asked whether the incorporation of illegitimate interactions into the analysis affects plant-hummingbird network structure. We identified 97 plant species visited by P. ruber and found that P. ruber engaged in floral larceny in almost 30% of these species. Nectar robbery was especially common in flowers with longer corolla. In terms of the effect on C. paniculata, the depletion of nectar due to robbery by P. ruber was associated with decreased visitation rates of legitimate pollinators. At the community level, the inclusion of the illegitimate visits of P. ruber resulted in modifications of how modules within the network were organized, notably giving rise to a new module consisting of P. ruber and mostly robbed flowers. However, although illegitimate visits constituted approximately 9% of all interactions in the network, changes in nestedness, modularity, and network-level specialization were minor. Our results indicate that although a flower robber may have a strong effect on the pollination of a particular plant species, the inclusion of its illegitimate interactions has limited capacity to change overall network structure.

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. 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).

  4. 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.

  5. 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.

  6. Isotopes in tropical agriculture

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1962-04-15

    Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

  7. Isotopes in tropical agriculture

    International Nuclear Information System (INIS)

    1962-01-01

    Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

  8. Tropical Diabetic Hand Syndrome

    African Journals Online (AJOL)

    2015 Annals of Medical and Health Sciences Research | Published by Wolters Kluwer - Medknow. 473. Introduction ... diabetes.[2,3] Tropical diabetic hand syndrome is a terminology .... the importance of seeking medical attention immediately.

  9. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts

    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.

  10. GARP Atlantic Tropical Experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The GARP Atlantic Tropical Experiment (GATE) was the first major international experiment of the Global Atmospheric Research Program (GARP). It was conducted over...

  11. 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

  12. Pneumonia in the tropics.

    Science.gov (United States)

    Lim, Tow Keang; Siow, Wen Ting

    2018-01-01

    Pneumonia in the tropics poses a heavy disease burden. The complex interplay of climate change, human migration influences and socio-economic factors lead to changing patterns of respiratory infections in tropical climate but also increasingly in temperate countries. Tropical and poorer countries, especially South East Asia, also bear the brunt of the global tuberculosis (TB) pandemic, accounting for almost one-third of the burden. But, as human migration patterns evolve, we expect to see more TB cases in higher income as well as temperate countries, and rise in infections like scrub typhus from ecotourism activities. Fuelled by the ease of air travel, novel zoonotic infections originating from the tropics have led to global respiratory pandemics. As such, clinicians worldwide should be aware of these new conditions as well as classical tropical bacterial pneumonias such as melioidosis. Rarer entities such as co-infections of leptospirosis and chikungunya or dengue will need careful consideration as well. In this review, we highlight aetiologies of pneumonia seen more commonly in the tropics compared with temperate regions, their disease burden, variable clinical presentations as well as impact on healthcare delivery. © 2017 Asian Pacific Society of Respirology.

  13. Neglected tropical diseases outside the tropics.

    Directory of Open Access Journals (Sweden)

    Francesca F Norman

    Full Text Available BACKGROUND: The neglected tropical diseases (NTDs cause significant morbidity and mortality worldwide. Due to the growth in international travel and immigration, NTDs may be diagnosed in countries of the western world, but there has been no specific focus in the literature on imported NTDs. METHODS: Retrospective study of a cohort of immigrants and travelers diagnosed with one of the 13 core NTDs at a Tropical Medicine Referral Unit in Spain during the period April 1989-December 2007. Area of origin or travel was recorded and analyzed. RESULTS: There were 6168 patients (2634 immigrants, 3277 travelers and 257 VFR travelers in the cohort. NTDs occurred more frequently in immigrants, followed by VFR travelers and then by other travelers (p<0.001 for trend. The main NTDs diagnosed in immigrants were onchocerciasis (n = 240, 9.1% acquired mainly in sub-Saharan Africa, Chagas disease (n = 95, 3.6% in immigrants from South America, and ascariasis (n = 86, 3.3% found mainly in immigrants from sub-Saharan Africa. Most frequent NTDs in travelers were: schistosomiasis (n = 43, 1.3%, onchocerciasis (n = 17, 0.5% and ascariasis (n = 16, 0.5%, and all were mainly acquired in sub-Saharan Africa. The main NTDs diagnosed in VFR travelers were onchocerciasis (n = 14, 5.4%, and schistosomiasis (n = 2, 0.8%. CONCLUSIONS: The concept of imported NTDs is emerging as these infections acquire a more public profile. Specific issues such as the possibility of non-vectorial transmission outside endemic areas and how some eradication programmes in endemic countries may have an impact even in non-tropical western countries are addressed. Recognising NTDs even outside tropical settings would allow specific prevention and control measures to be implemented and may create unique opportunities for research in future.

  14. Symmetric and arbitrarily high-order Birkhoff-Hermite time integrators and their long-time behaviour for solving nonlinear Klein-Gordon equations

    Science.gov (United States)

    Liu, Changying; Iserles, Arieh; Wu, Xinyuan

    2018-03-01

    The Klein-Gordon equation with nonlinear potential occurs in a wide range of application areas in science and engineering. Its computation represents a major challenge. The main theme of this paper is the construction of symmetric and arbitrarily high-order time integrators for the nonlinear Klein-Gordon equation by integrating Birkhoff-Hermite interpolation polynomials. To this end, under the assumption of periodic boundary conditions, we begin with the formulation of the nonlinear Klein-Gordon equation as an abstract second-order ordinary differential equation (ODE) and its operator-variation-of-constants formula. We then derive a symmetric and arbitrarily high-order Birkhoff-Hermite time integration formula for the nonlinear abstract ODE. Accordingly, the stability, convergence and long-time behaviour are rigorously analysed once the spatial differential operator is approximated by an appropriate positive semi-definite matrix, subject to suitable temporal and spatial smoothness. A remarkable characteristic of this new approach is that the requirement of temporal smoothness is reduced compared with the traditional numerical methods for PDEs in the literature. Numerical results demonstrate the advantage and efficiency of our time integrators in comparison with the existing numerical approaches.

  15. How do anthropogenic contaminants (ACs) affect behaviour? Multi-level analysis of the effects of copper on boldness in hermit crabs.

    Science.gov (United States)

    White, Stephen J; Briffa, Mark

    2017-02-01

    Natural animal populations are increasingly exposed to human impacts on the environment, which could have consequences for their behaviour. Among these impacts is exposure to anthropogenic contaminants. Any environmental variable that influences internal state could impact behaviour across a number of levels: at the sample mean, at the level of among-individual differences in behaviour ('animal personality') and at the level of within-individual variation in behaviour (intra-individual variation, 'IIV'). Here we examined the effect of exposure to seawater-borne copper on the startle response behaviour of European hermit crabs, Pagurus bernhardus across these levels. Copper exposure rapidly led to longer startle responses on average, but did not lead to any change in repeatability indicating that individual differences were present and equally consistent in the presence and absence of copper. There was no strong evidence that copper exposure led to changes in IIV. Our data show that exposure to copper for 1 week produces sample mean level changes in the behaviour of hermit crabs. However, there is no evidence that this exposure led to changes in repeatability through feedback loops.

  16. Connection between quantum systems involving the fourth Painlevé transcendent and k-step rational extensions of the harmonic oscillator related to Hermite exceptional orthogonal polynomial

    Energy Technology Data Exchange (ETDEWEB)

    Marquette, Ian, E-mail: i.marquette@uq.edu.au [School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072 (Australia); Quesne, Christiane, E-mail: cquesne@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, Université Libre de Bruxelles, Campus de la Plaine CP229, Boulevard du Triomphe, B-1050 Brussels (Belgium)

    2016-05-15

    The purpose of this communication is to point out the connection between a 1D quantum Hamiltonian involving the fourth Painlevé transcendent P{sub IV}, obtained in the context of second-order supersymmetric quantum mechanics and third-order ladder operators, with a hierarchy of families of quantum systems called k-step rational extensions of the harmonic oscillator and related with multi-indexed X{sub m{sub 1,m{sub 2,…,m{sub k}}}} Hermite exceptional orthogonal polynomials of type III. The connection between these exactly solvable models is established at the level of the equivalence of the Hamiltonians using rational solutions of the fourth Painlevé equation in terms of generalized Hermite and Okamoto polynomials. We also relate the different ladder operators obtained by various combinations of supersymmetric constructions involving Darboux-Crum and Krein-Adler supercharges, their zero modes and the corresponding energies. These results will demonstrate and clarify the relation observed for a particular case in previous papers.

  17. 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.

  18. 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.

  19. Distribución de cangrejos ermitaños (Anomura: Paguroidea en el mar Caribe colombiano Hermit crabs (Anomura: Paguroidea distribution patterns in the Colombian Caribbean Sea

    Directory of Open Access Journals (Sweden)

    Bibian Martínez Campos

    2012-03-01

    Full Text Available Los cangrejos ermitaños son un grupo representativo de la fauna marina del Caribe colombiano, además, son importantes en el mantenimiento del equilibrio dinámico, en los ecosistemas por sus interacciones ecológicas y también por el impacto en la estabilidad de las redes tróficas. Sus patrones de distribución se identificaron mediante análisis multivariados de clasificación y ordenación espacial, se usaron registros históricos desde 1916 hasta el 2006. Los resultados indican diferencias por profundidad entre la fauna costera y la del talud continental y diferencias en la distribución latitudinal, en donde se encontraron tres grupos: Noreste, Centro y Suroeste, sustentados por diferencias en la composición faunística. Con base en los mapas de ecosistemas marinos de Colombia, se determinó que los principales factores que afectan su distribución son la influencia del talud Caribaná (profundidad, la temperatura de las masas de agua, las praderas de pastos marinos de la Guajira y las condiciones particulares de las ecorregiones Archipiélagos coralinos y Darién. Se identificó la distribución mundial de las especies colombianas y su afinidad geográfica, y se encontró mayor afinidad con el Atlántico norte y las Antillas que con el Atlántico sur y el Golfo de México, asimismo, las subprovincias geográficas que incluyen a Colombia son zonas de transición dentro de la subprovincias septentrionales y australes del Gran CaribeHermit crabs (Anomura: Paguroidea distribution patterns in the Colombian Caribbean Sea. Hermit crabs represent the marine life in the Colombian Caribbean, and are important for the dynamic equilibrium maintenance in ecosystems, the ecological interactions and their impact on food web stability. Generally, in order to come up with some conservation strategies, strong bio-geographical information is needed for policies definition. With this aim, this study analyzed the distribution patterns of hermit crabs in

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. Tropical Agro-Sciences

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The Tropical Agro-Sciences Division has two functions: conduct research on the impact of air pollution on tropical agricultural and to provide training to UPR graduate students and visiting scientists. Since the reorientation of the Center's interests under ERDA, the Division has directed its research activities, with particular emphasis on the effects of atmospheric pollution on tropical agriculture in the Guayanilla-Penuelas region, which has a fossil-fuel power plant, petroleum refineries, and associated industries. This new area of research is important to ERDA because the knowledge gained regarding the effects of air pollution related to energy technology on the agricultural environment and productivity will be useful in planning future energy developments. Information about the potential harm of air pollutants to man through the food chain and about ways of alleviating their impact on agriculture are of practical importance. Studies of the mechanisms involved in pollution injury, protection, and tolerance are of basic significance

  10. 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.

  11. 1997 Annual Tropical Cyclone Report

    National Research Council Canada - National Science Library

    Dillon, C

    1997-01-01

    .... Separate bulletins are issued for the Western Pacific and the Indian Ocean. TROPICAL CYCLONE FORMATION ALERT - Defines a specific area when synoptic, satellite, or other germane data indicate development of a significant tropical cyclone (TC...

  12. A quantitative determination of air-water heat fluxes in Hermit Lake, New Hampshire under varying meteorological conditions, time of day, and time of year

    Science.gov (United States)

    Kyper, Nicholas D.

    An extensive heat flux study is performed at Hermit Lake, New Hampshire from May 26, 2010 till November 7, 2010 to determine the effects of the five individual heat fluxes on Hermit Lake and the surrounding amphibian community. Hermit Lake was chosen due to the relatively long meteorological observations record within the White Mountains of New Hampshire, a new lakeside meteorological station, and ongoing phenology studies of the surrounding eco-system. Utilizing meteorological data from the lakeside weather station and moored water temperature sensors, the incident (Qi), blackbody ( Qbnet ), latent (Qe), sensible (Q s), and net (Qn) heat fluxes are calculated. The incident heat flux is the dominate term in the net flux, accounting for 93% of the variance found in Qn and producing a heat gain of ˜ 19x108 J m-2 throughout the period of study. This large gain produces a net gain of heat in the lake until October 1, 2010, where gains by Qi are offset by the large combined losses of Qbnet , Qs, and Qe thereby producing a gradual decline of heat within the lake. The latent and blackbody heat fluxes produce the largest losses of heat in the net heat flux with a total losses of ˜ -8x108 J m-2 and ˜ -7x108 J m-2, respectively. The sensible heat flux is negligible, producing a total minimal loss of ˜ -1x108 J m-2. Overall the net heat produces a net gain of heat of 2x108 J m-2 throughout the study period. Frog calls indicative of breeding are recorded from May 26, 2010 until August 16, 2010. The spring peeper, American toad, and green frog each produced enough actively calling days to be compared to air temperature, surface water temperature, and wind speed data, as well as data from the five heat fluxes. Linear regression analysis reveals that certain water temperature thresholds affect the calling activities of the spring peeper and green frog, while higher wind speeds have a dramatic effect on the calling activities of both the green frog and American toad. All three

  13. Tropical varieties, maps and gossip

    NARCIS (Netherlands)

    Frenk, B.J.

    2013-01-01

    Tropical geometry is a relatively new field of mathematics that studies the tropicalization map: a map that assigns a certain type of polyhedral complex, called a tropical variety, to an embedded algebraic variety. In a sense, it translates algebraic geometric statements into combinatorial ones. An

  14. Tropical Cyclone Report, 1988

    Science.gov (United States)

    1988-01-01

    Cmdr. David Gray; National Weather Service 5. Cooperation with the Naval Environmental Pacific Region for the startup of 24-hour operatiois at Ponape...0.1 27.7 TOTAL CASES 3 1 1 4 12 27 54 56 30 25 7 1 221 * (GRAY, 1979) TABLE 4-3 ANNUAL VARIATION C SOTR MUSHER TROPICAL CYCLOUZ BY O(EN BASIN SOUTH

  15. Utilization of tropical rabbits

    African Journals Online (AJOL)

    5,0' a,b"differ (P<0,05) for reproducing rabbits, and may aid the prevention of enteric diseases. In Trial 3, ADG of several tropical legumes was the same as that obtained with alfalfa (Table 3). Gains with guinea grass, cassava, stylosanthes and the winged bean were lower than with alfalfa. Digestibilityof the protein and fibre ...

  16. [Tropical sprue (author's transl)].

    Science.gov (United States)

    Gras, C; Chapoy, P; Aubry, P

    1981-01-01

    Tropical sprue is a disease of the small intestine characterized by a malabsorption syndrome with a subtotal or partial mucosal atrophy. It is observed in Asia and Central America. It appears to be rare in Africa but its real frequency is unknown as small bowel biopsys are not routinely done. Bacterial overgrowth as well as giardiasis may be trigger factors of the disease the pathogenesis of which is still incompletely understood. The disease beginning as chronic diarrhea is later on characterized by an aphtoïd stomatitis and a macrocytic anemia. Treatment with antibiotics and folic acid is efficient and has a diagnostic value. If treatment is started lately, vitamin B 12 is then also necessary. In any intestinal syndrome observed in tropical areas without an ascertained etiologic diagnosis, peroral biopsie of the small intestine is requested. However, with the use of pediatric endoscope it will be possible to appreciate the respective incidence of tropical sprue and asymptomatic tropical sprue in Africa South of the Sahara.

  17. Securing tropical forest carbon

    DEFF Research Database (Denmark)

    Scharlemann, Jörn P. W.; Kapos, Valerie; Campbell, Alison

    2010-01-01

    Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate...... that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation...... in protected sites in humid tropical forests could be valued at USD 6,200-7,400 million depending on the land use after clearance. This is >1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important...

  18. Tropic Testing of Vehicles

    Science.gov (United States)

    2014-08-27

    kilometer track running through tropical forest. The track is a combination of a bauxite /dirt base with grades on the road up to 20 percent and log...bridges crossing 11 creeks. The track site is located in a private concession used mainly for gold mining ; however, logging operations are active in the

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Tropical myeloneuropathies: the hidden endemias.

    Science.gov (United States)

    Román, G C; Spencer, P S; Schoenberg, B S

    1985-08-01

    Tropical myeloneuropathies include tropical ataxic neuropathy and tropical spastic paraparesis. These disorders occur in geographic isolates in several developing countries and are associated with malnutrition, cyanide intoxication from cassava consumption, tropical malabsorption (TM), vegetarian diets, and lathyrism. TM-malnutrition was a probable cause of myeloneuropathies among Far East prisoners of war in World War II. Clusters of unknown etiology occur in India, Africa, the Seychelles, several Caribbean islands, Jamaica, and Colombia. Treponemal infection (yaws) could be an etiologic factor in the last two. Tropical myeloneuropathies, a serious health problem, are multifactorial conditions that provide unsurpassed opportunities for international cooperation and neurologic research.

  18. Functional connectivity experiments reflect routine movement behavior of a tropical hummingbird species.

    Science.gov (United States)

    Volpe, Noelia L; Hadley, Adam S; Robinson, W Douglas; Betts, Matthew G

    Translocation experiments, in which researchers displace animals and then monitor their movements to return home, are commonly used as tools to assess functional connectivity of fragmented landscapes. Such experiments are purported to have important advantages of being time efficient and of standardizing “motivation” to move across individuals. Yet, we lack tests of whether movement behavior of translocated birds reflects natural behavior of unmanipulated birds. We compared the routine movement behavior of a tropical hummingbird, the Green Hermit (Phaethornis guy), to that of experimentally translocated individuals. We tested for differences in site selection patterns during movement at two spatial scales (point and path levels). We also compared movement rates between treatments. Behaviors documented during translocation experiments reflected those observed during routine movements. At the point level, both translocated and non-translocated birds showed similar levels of preference for mature tropical forest. At the path level, step selection functions showed both translocated and non-translocated hummingbirds avoiding movement across non-forested matrix and selecting streams as movement corridors. Movement rates were generally higher during translocation experiments. However, the negative influence of forest cover on movement rates was proportionately similar in translocation and routine movement treatments. We report the first evidence showing that movement behavior of birds during translocation experiments is similar to their natural movement behavior. Therefore, translocation experiments may be reliable tools to address effects of landscape structure on animal movement. We observed consistent selection of landscape elements between translocated and non-translocated birds, indicating that both routine and translocation movement studies lead to similar conclusions regarding the effect of landscape structure and forest composition on functional connectivity

  19. Analytical investigation on domain of decentered parameter for self-focusing of Hermite-cosh-Gaussian laser beam in collisional plasma

    Science.gov (United States)

    Valkunde, Amol T.; Patil, Sandip D.; Vhanmore, Bandopant D.; Urunkar, Trupti U.; Gavade, Kusum M.; Takale, Mansing V.; Fulari, Vijay J.

    2018-03-01

    In the present paper, an analytically investigated domain of decentered parameter and its effect on the self-focusing of Hermit-cosh-Gaussian (HChG) laser beams in a collisional plasma have been studied theoretically. The nonlinearity in the dielectric constant of plasma arising due to the nonuniform heating of carriers along the wavefront of the laser beam has been employed in the present investigation. The nonlinear differential equation of beam width parameter for various laser modes of HChG beam is obtained by following the standard Akhamanov's parabolic equation approach under Wentzel-Kramers-Brillouin and paraxial approximations. The analytical treatment has enabled us to define three distinct regions: self-focusing, self-trapping and defocusing, which are presented graphically.

  20. A new species of the genus Peltogaster Rathke, 1842 (Cirripedia: Rhizocephala: Peltogastridae) parasitizing the hermit crab Pagurixus boninensis (Melin, 1939) from the Bonin Islands, Japan.

    Science.gov (United States)

    Yoshida, Ryuta; Naruse, Tohru

    2016-07-20

    A new rhizocephalan species, Peltogaster unigibba n. sp., is described from the host hermit crab, Pagurixus boninensis (Melin, 1939), from the Bonin Islands, Japan. Of the16 known species of Peltogaster now currently recognised, P. unigibba n. sp., and P. contorta Boschma, 1958 share a left lobe that projects beyond the mantle aperture. The two species can be distinguished from one another by the position of the opening of the mantle aperture. The new species most closely resembles P. naushonensis Reinhard, 1946 in its internal structure, but clearly differs in the relative length of the colleteric glands. Peltogaster unigibba n. sp. represents the first record of a rhizocephalan from the oceanic Bonin Islands, and the second record of a rhizocephalan from an oceanic island in the northern hemisphere.

  1. Tropical vegetation evidence for rapid sea level changes associated with Heinrich Events

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Catalina; Dupont, Lydie M, E-mail: catalina@uni-bremen.d, E-mail: dupont@uni-bremen.d [MARUM - Centre for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Germany (Germany)

    2010-03-15

    A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3. Rapid and abrupt expansions of salt marsh vegetation in tropical South America are associated with north Atlantic Heinrich Events stadials (HE-stadials). Intervals of salt marsh expansion have an internal structure, which consists of a recurrent alternation of species that starts with pollen increments of Chenopodiaceae, that are followed by increments of grasses, and subsequently by increments of Cyperaceae. This pattern suggests a successional process that is determined by the close relationship between sea-level and plant community dynamics. The salt tolerant Chenopodiaceae, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE-stadials, causing the continued recruitment of pioneer species, which are the only ones tolerating rapid rates of disturbance. Once sea-level rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species. These results add to the scarce knowledge on the dynamics of tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes following Antarctic climate variability.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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...

  10. 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

  11. 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

  12. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts

    2008-05-15

    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.  Created: 5/15/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/29/2008.

  13. [Tropical causes of epilepsy].

    Science.gov (United States)

    Carod-Artal, F J

    Eighty-five percent of all epileptics live in tropical regions. Prenatal risk factors, traumatic brain injuries and different parasitic infestations of the central nervous system (CNS) are the reasons behind the high prevalence of epilepsy. This work reviews the main parasitic infestations causing epilepsy in the tropics. Neurocysticercosis is the main cause of focal epilepsy in early adulthood in endemic areas (30-50%). All the phases of cysticerci (viable, transitional and calcified) are associated with epileptic seizures. Anti-cysticercus treatment helps get rid of cysticerci faster and reduces the risk of recurrence of seizures in patients with viable cysts. Symptomatic epilepsy can be the first manifestation of neuroschistosomiasis in patients without any systemic symptoms. The pseudotumoral form can trigger seizures secondary to the presence of granulomas and oedemas in the cerebral cortex. The eggs of Schistosoma japonicum are smaller, reach the CNS more easily and trigger epileptic seizures more frequently. Toxocariasis and sparganosis are other parasitic infestations that can give rise to symptomatic seizures. The risk factors for suffering chronic epilepsy after cerebral malaria are a positive familial history of epilepsy and a history of episodes of fever and cerebral malaria that began with coma or which progressed with multiple, prolonged epileptic seizures. About 20% of patients with cerebral infarction secondary to Chagas disease present late vascular epilepsy as a complication. Very few studies have been conducted to examine the prognosis, risk of recurrence and modification of the natural course of seizures associated with tropical parasitic infestations, except for the case of neurocysticercosis.

  14. 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

  15. Tropical Peatland Geomorphology and Hydrology

    Science.gov (United States)

    Cobb, A.; Harvey, C. F.

    2017-12-01

    Tropical peatlands cover many low-lying areas in the tropics. In tropical peatlands, a feedback between hydrology, landscape morphology, and carbon storage causes waterlogged organic matter to accumulate into gently mounded land forms called peat domes over thousands of years. Peat domes have a stable morphology in which peat production is balanced by loss and net precipitation is balanced by lateral flow, creating a link between peatland morphology, rainfall patterns and drainage networks. We show how landscape morphology can be used to make inferences about hydrologic processes in tropical peatlands. In particular, we show that approaches using simple storage-discharge relationships for catchments are especially well suited to tropical peatlands, allowing river forecasting based on peatland morphology in catchments with tropical peatland subcatchments.

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. 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.

  1. 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)

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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...

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. Tannins in tropical woods

    Energy Technology Data Exchange (ETDEWEB)

    Doat, J

    1978-01-01

    A preliminary study was made of the chemistry of pyrogallol- and catecholtannins, their general properties and methods of extraction and determination. Three methods of estimation - Lowenthal, powdered hide and spectrophotometry - were compared using two control solutions, four samples of wood and one of bark. Using the empirical powdered hide method, tannins of both types were estimated in wood and bark of various tropical species (some separately and some as a mixture), Moroccan oaks (Quercus suber and Q. ilex), and European oak 9Q. petraea). Further tests were made on the wood and bark of the two mangrove species, Rhizophora mangle and R. racemosa, by subjecting them to successive extraction with a range of solvents. None of the woods tested had as much as the 10% of tannins considered necessary in economic sources. The bark of the two mangroves, of Eucalyptus urophylla and of Prosopis africana had tannin contents over 10% and the latter two species had very favorable tannin/non-tannin ratios. All the tropical species, with the probable exception of E. urophylla, had only catecholtannins. Only the oaks and E. urophylla bark gave positive results when tested for gallotannins.

  16. Tropical Cyclone Information System

    Science.gov (United States)

    Li, P. Peggy; Knosp, Brian W.; Vu, Quoc A.; Yi, Chao; Hristova-Veleva, Svetla M.

    2009-01-01

    The JPL Tropical Cyclone Infor ma tion System (TCIS) is a Web portal (http://tropicalcyclone.jpl.nasa.gov) that provides researchers with an extensive set of observed hurricane parameters together with large-scale and convection resolving model outputs. It provides a comprehensive set of high-resolution satellite (see figure), airborne, and in-situ observations in both image and data formats. Large-scale datasets depict the surrounding environmental parameters such as SST (Sea Surface Temperature) and aerosol loading. Model outputs and analysis tools are provided to evaluate model performance and compare observations from different platforms. The system pertains to the thermodynamic and microphysical structure of the storm, the air-sea interaction processes, and the larger-scale environment as depicted by ocean heat content and the aerosol loading of the environment. Currently, the TCIS is populated with satellite observations of all tropical cyclones observed globally during 2005. There is a plan to extend the database both forward in time till present as well as backward to 1998. The portal is powered by a MySQL database and an Apache/Tomcat Web server on a Linux system. The interactive graphic user interface is provided by Google Map.

  17. Tropical Rainforest Education. ERIC Digest.

    Science.gov (United States)

    Rillero, Peter

    This digest provides four guideposts for tropical rainforest education: (1) structure; (2) location and climate; (3) importance; and (4) conservation of resources. Research is cited and background information provided about the layers of life and the adaptations of life within the tropical rain forest. Aspects of life within and near rain forests…

  18. Mycorrhizas and tropical soil fertility

    NARCIS (Netherlands)

    Cardoso, I.M.; Kuyper, T.W.

    2006-01-01

    Major factors that constrain tropical soil fertility and sustainable agriculture are low nutrient capital, moisture stress, erosion, high P fixation, high acidity with aluminium toxicity, and low soil biodiversity. The fragility of many tropical soils limits food production in annual cropping

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. A Quadratic Model with Nonpolynomial Terms for Remote Colorimetric Calibration of 3D Laser Scanner Data Based on Piecewise Cubic Hermite Polynomials

    Directory of Open Access Journals (Sweden)

    Alessandro Danielis

    2015-01-01

    Full Text Available The processing of intensity data from terrestrial laser scanners has attracted considerable attention in recent years. Accurate calibrated intensity could give added value for laser scanning campaigns, for example, in producing faithful 3D colour models of real targets and classifying easier and more reliable automatic tools. In cultural heritage area, the purely geometric information provided by the vast majority of currently available scanners is not enough for most applications, where indeed accurate colorimetric data is needed. This paper presents a remote calibration method for self-registered RGB colour data provided by a 3D tristimulus laser scanner prototype. Such distinguishing colour information opens new scenarios and problems for remote colorimetry. Using piecewise cubic Hermite polynomials, a quadratic model with nonpolynomial terms for reducing inaccuracies occurring in remote colour measurement is implemented. Colorimetric data recorded by the prototype on certified diffusive targets is processed for generating a remote Lambertian model used for assessing the accuracy of the proposed algorithm. Results concerning laser scanner digitizations of artworks are reported to confirm the effectiveness of the method.

  16. Tropical Plant Collections

    DEFF Research Database (Denmark)

    Friis, Ib; Balslev, Henrik

    that involved Germany, Britain and France, until independence, which was brightened by exemplary collaboration. Muasya focussed on South Africa, which is the most developed country in sub-Saharan Africa with a well-functioning network of herbaria that covers widely different biota. Sanjappa outlined the history...... crisis. Friis gave a broad overview of the history of herbaria and botanical gardens and the changing conceptual frameworks behind their existence. Baldini talked about early Italian botanical collectors and the fate of their collections. Baas accounted for the Golden Age of Dutch botany during pre......-colonial and early colonial periods. With the presentation by Cribb on the botany of the British Empire we were fully into the colonial period, focussing on the Royal Botanic Gardens at Kew. The situation in North America was treated by Funk, who illustrated the development of collections of tropical plants...

  17. 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

  18. Seagrasses in tropical Australia, productive and abundant for decades decimated overnight.

    Science.gov (United States)

    Pollard, Peter C; Greenway, Margaret

    2013-03-01

    Seagrass ecosystems provide unique coastal habitats critical to the life cycle of many species. Seagrasses are a major store of organic carbon. While seagrasses are globally threatened and in decline, in Cairns Harbour, Queensland, on the tropical east coast of Australia, they have flourished. We assessed seagrass distribution in Cairns Harbour between 1953 and 2012 from historical aerial photographs, Google map satellite images, existing reports and our own surveys of their distribution. Seasonal seagrass physiology was assessed through gross primary production, respiration and photosynthetic characteristics of three seagrass species, Cymodocea serrulata, Thalassia hemprichii and Zostera muelleri. At the higher water temperatures of summer, respiration rates increased in all three species, as did their maximum rates of photosynthesis. All three seagrasses achieved maximum rates of photosynthesis at low tide and when they were exposed. For nearly six decades there was little change in seagrass distribution in Cairns Harbour. This was most likely because the seagrasses were able to achieve sufficient light for growth during intertidal and low tide periods. With historical data of seagrass distribution and measures of species production and respiration, could seagrass survival in a changing climate be predicted? Based on physiology, our results predicted the continued maintenance of the Cairns Harbour seagrasses, although one species was more susceptible to thermal disturbance. However, in 2011 an unforeseen episodic disturbance - Tropical Cyclone Yasi - and associated floods lead to the complete and catastrophic loss of all the seagrasses in Cairns Harbour.

  19. Patterns in tropical seagrass photosynthesis in relation to light, depth and habitat

    Science.gov (United States)

    Campbell, Stuart J.; McKenzie, Len J.; Kerville, Simon P.; Bité, Juanita S.

    2007-07-01

    Seagrass meadows across north-eastern Australia, survive a range of environmental conditions in coastal bays, reefs, estuarine and deepwater habitats through adaptation of a range of structural, morphological and physiological features. The aim of this study was to investigate the influence of spatial features (habitat type, site and depth) and photon flux on the photosynthetic performance of 11 tropical seagrass species. Pulse amplitude modulated (PAM) fluorometry was used to generate rapid light curves from which measures of maximal electron transport rate (ETR max), photosynthetic efficiency ( α), saturating irradiance ( Ek) and effective quantum yield (Δ F/ Fm') were derived. The amount of light absorbed by leaves (absorption factor) was also determined for each population. In intertidal habitats many seagrass species exhibited typical sun-type responses with a close coupling of both ETR max and Ek with photon flux. Photosynthetic performance ranged from minima in Thalassodendron ciliatum to maxima in Syringodium isoetifolium. The absence of a coupling between photosynthetic performance and photon flux in subtidal populations was most likely due to highly variable light climates and possible light attenuation, and hence the photo-biology of estuarine and deepwater seagrasses exhibited photosynthetic responses indicative of light limitation. In contrast seagrass species from shallow reef and coastal habitats for the most part exhibited light saturation characteristics. Of all the variables examined ETR max, Ek and Δ F/ Fm' were most responsive to changing light climates and provide reliable physiological indicators of real-time photosynthetic performance of tropical seagrasses under different light conditions.

  20. 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

  1. FAQ HURRICANES, TYPHOONS, AND TROPICAL CYCLONES

    Science.gov (United States)

    ? A6) What is a sub-tropical cyclone? A7) What is an extratropical cyclone ? A8) What is storm surge easterly wave and what causes them? A5) What is a tropical disturbance, tropical depression, tropical storm and how is it different from storm tide ? A9) What is a "CDO" ? A10) What is a TUTT ? A11

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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)

  6. 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.

  7. Tropical Journal of Health Sciences

    African Journals Online (AJOL)

    The Tropical Journal of Health Sciences (TJHS) is an international journal which ... of ideas to those engaged in work in the Health Sciences and related fields. The journal intends to publish high quality papers on original research, case ...

  8. Tropical Journal of Pharmaceutical Research

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 12, No 6 (2013) >. Log in or Register to get access to full text downloads.

  9. JPL Tropical Cyclone Information System

    Data.gov (United States)

    National Aeronautics and Space Administration — The JPL Tropical Cyclone Information System (TCIS) brings together satellite and in situ data sets from various sources to help you find information for a particular...

  10. Tropical Journal of Pharmaceutical Research

    African Journals Online (AJOL)

    We seek to encourage pharmaceutical and allied research of tropical and ... and related disciplines (including biotechnology, cell and molecular biology, drug ... with ibrutinib reduces proliferation, migration and invasion of lung cancer cells ...

  11. 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

  12. Tropical forests. Nettai no shinrin

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, I [Kyoto Univ., Kyoto (Japan)

    1991-11-05

    It was in 1950s when felling of tropical forests started in earnest, in 1970s felling of forest trees in Southeast Asia reached its peak and the destnation of exportation of most of them was Japan. Besides, among the present overseas development assistance projects (ODA) of Japan, her role to be played in connection with tropical forests is not small and its funds, which surpass by far the budget for forestry of the United Nations Food and Agriculture Organization (FAO), are aiding cooperation projects on forestry in many places in the world. Nevertheless, in Japan, the understanding of tropical forests is insufficient and its realities have not been known. In this article, based on the experience and knowledge of the author who stayed in Kalimantan, various kinds of problems concerning tropical forests are explained, the realities are introduced on information, well trained people, funds and philosophy which are far short in pursuance of the problems of tropical forests. Furthermore, as the issues hereafter, such proposals on tropical forests are made as protection of natural forests, planned operation in respecting self renewal ability of the secondary forests and afforestation of alang-alang grassy plains resulted from the failure of burning felled trees and grasses for making the land arable. 1 ref..

  13. Competitive interactions among zoanthids (cnidaria: zoanthidae in an intertidal zone of northeastern Brazil

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    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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Facing the Heat: Does Desiccation and Thermal Stress Explain Patterns of Orientation in an Intertidal Invertebrate?

    Directory of Open Access Journals (Sweden)

    Clarissa M L Fraser

    Full Text Available 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.

  5. 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.

  6. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  7. Interspecific competition for shelters in territorial and gregarious intertidal grazers: consequences for individual behaviour.

    Directory of Open Access Journals (Sweden)

    Moisés A Aguilera

    Full Text Available Experiments have shown that interspecific interactions within consumer guilds can alter patterns of distribution, abundance and size of species. Plastic behavioural responses can be modulated by agonistic interactions. In many cases, consumers compete for space and shelters, and these interactions change the manner in which they exploit food. This study investigates the consequences of competition in the spatial and temporal organization of behaviour of intertidal grazers, which share algal resources and the use of rock crevices while resting, but exhibit different body sizes, spatial behaviour and foraging modes. We evaluate interaction strength between small gregarious Siphonaria lessoni and the larger territorial keyhole limpet Fissurella crassa and between S. lessoni and the medium-size gregarious chiton Chiton granosus. Using field manipulations and artificial arenas in the laboratory, we tested whether the use of crevices, micro-spatial distribution and activity are modified by the density of conspecifics and the presence of heterospecifics. Our results show that small-scale spatial segregation observed in the field between S. lessoni and C. granosus result from species-specific differences in habitat use. In turn, we found evidence that spatial segregation between F. crassa and S. lessoni results from highly asymmetric interference competition in the use of shelters. The presence of F. crassa reduced the use of crevices and growth rates of S. lessoni. Effects on growth rates are assumed to result from exposure to harsh environmental conditions rather than food limitation. Thus, neither gregarious behaviour nor differences in activity were sufficient to prevent competition with the larger grazer. Our study illustrates the importance of competition for shelters, which results in behavioural changes of the smaller-sized species, and how these plastic responses can translate into differences in growth rates. Use of shelters can thus be

  8. The morphodynamics and internal structure of intertidal fine-gravel dunes: Hills Flats, Severn Estuary, UK

    Science.gov (United States)

    Carling, P. A.; Radecki-Pawlik, A.; Williams, J. J.; Rumble, B.; Meshkova, L.; Bell, P.; Breakspear, R.

    2006-01-01

    In the macrotidal Severn estuary, UK, the dynamics of intertidal fine-gravel dunes were investigated. These dunes are migrating across a bedrock platform. Systematic observations were made of hydraulic climate, geometry, migration rates and internal sedimentary structures of the dunes. During spring tides, the ebb flow is dominant, dunes grow in height and have ebb orientated geometry with bedrock floors in the troughs. During neap tides, a weak flood flow may dominate. Dunes then are flood orientated or symmetrical. Neap dune heights decrease and the eroded sediment is stored in the dune troughs where the bedrock becomes blanketed by muddy gravel. During spring tides, instantaneous bed shear stresses reach 8 N m - 2 , sufficient to disrupt a 9 mm-gravel armour layer. However, a sustained bed shear stress of 4 N m - 2 is required to initiate dune migration at which time the critical depth-mean velocity is 1 m s - 1 . Ebb and flood inequalities in the bed shear stress explain the changes in dune asymmetry and internal structures. During flood tides, the crests of the dunes reverse such that very mobile sedimentary 'caps' overlie a more stable dune 'core'. Because ebb tides dominate, internal structures of the caps often are characterised by ebb orientated steep open-work foresets developed by strong tidal currents and some lower angle crossbeds deposited as weaker currents degrade foresets. The foresets forming the caps may be grouped into cosets (tidal bundles) and are separated from mud-infused cores of crossbeds that lie below, by reactivation and erosion surfaces blanketed by discontinuous mud drapes. The cores often exhibit distinctive muddy toe sets that define the spacing of tidal cosets.

  9. 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. PMID:26959815

  10. Enrichment of the hydrogen-producing microbial community from marine intertidal sludge by different pretreatment methods

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongyan [Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Shinan District, Qingdao 266071, Shandong (China); College of Marine Science and Engineering, University of Science and Technology, Tianjin 300457 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Wang, Guangce [Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Shinan District, Qingdao 266071, Shandong (China); College of Marine Science and Engineering, University of Science and Technology, Tianjin 300457 (China); Zhu, Daling; Pan, Guanghua [College of Marine Science and Engineering, University of Science and Technology, Tianjin 300457 (China)

    2009-12-15

    To determine the effects of pretreatment on hydrogen production and the hydrogen-producing microbial community, we treated the sludge from the intertidal zone of a bathing beach in Tianjin with four different pretreatment methods, including acid treatment, heat-shock, base treatment as well as freezing and thawing. The results showed that acid pretreatment significantly promoted the hydrogen production by sludge and provided the highest efficiency of hydrogen production among the four methods. The efficiency of the hydrogen production of the acid-pretreated sludge was 0.86 {+-} 0.07 mol H{sub 2}/mol glucose (mean {+-} S.E.), whereas that of the sludge treated with heat-shock, freezing and thawing, base method and control was 0.41 {+-} 0.03 mol H{sub 2}/mol glucose, 0.17 {+-} 0.01 mol H{sub 2}/mol glucose, 0.11 {+-} 0.01 mol H{sub 2}/mol glucose and 0.20 {+-} 0.04 mol H{sub 2}/mol glucose, respectively. The result of denaturing gradient gel electrophoresis (DGGE) showed that pretreatment methods altered the composition of the microbial community that accounts for hydrogen production. Acid and heat pretreatments were favorable to enrich the dominant hydrogen-producing bacterium, i.e. Clostridium sp., Enterococcus sp. and Bacillus sp. However, besides hydrogen-producing bacteria, much non-hydrogen-producing Lactobacillus sp. was also found in the sludge pretreated with base, freezing and thawing methods. Therefore, based on our results, we concluded that, among the four pretreatment methods using acid, heat-shock, base or freezing and thawing, acid pretreatment was the most effective method for promoting hydrogen production of microbial community. (author)

  11. Spatial assessment of intertidal seagrass meadows using optical imaging systems and a lightweight drone

    Science.gov (United States)

    Duffy, James P.; Pratt, Laura; Anderson, Karen; Land, Peter E.; Shutler, Jamie D.

    2018-01-01

    Seagrass ecosystems are highly sensitive to environmental change. They are also in global decline and under threat from a variety of anthropogenic factors. There is now an urgency to establish robust monitoring methodologies so that changes in seagrass abundance and distribution in these sensitive coastal environments can be understood. Typical monitoring approaches have included remote sensing from satellites and airborne platforms, ground based ecological surveys and snorkel/scuba surveys. These techniques can suffer from temporal and spatial inconsistency, or are very localised making it hard to assess seagrass meadows in a structured manner. Here we present a novel technique using a lightweight (sub 7 kg) drone and consumer grade cameras to produce very high spatial resolution (∼4 mm pixel-1) mosaics of two intertidal sites in Wales, UK. We present a full data collection methodology followed by a selection of classification techniques to produce coverage estimates at each site. We trialled three classification approaches of varying complexity to investigate and illustrate the differing performance and capabilities of each. Our results show that unsupervised classifications perform better than object-based methods in classifying seagrass cover. We also found that the more sparsely vegetated of the two meadows studied was more accurately classified - it had lower root mean squared deviation (RMSD) between observed and classified coverage (9-9.5%) compared to a more densely vegetated meadow (RMSD 16-22%). Furthermore, we examine the potential to detect other biotic features, finding that lugworm mounds can be detected visually at coarser resolutions such as 43 mm pixel-1, whereas smaller features such as cockle shells within seagrass require finer grained data (<17 mm pixel-1).

  12. Bedform Dimensions and Suspended Sediment Observations in a Mixed Sand-Mud Intertidal Environment

    Science.gov (United States)

    Lichtman, I. D.; Amoudry, L.; Peter, T.; Jaco, B.

    2016-02-01

    Small-scale bedforms, such as ripples, can profoundly modify near-bed hydrodynamics, near-bed sediment transport and resuspension, and benthic-pelagic fluxes. Knowledge of their dimensions is important for a number of applications. Fundamentally different processes can occur depending on the dimensions of ripples: for low and long ripples, the bed remains dynamically flat and diffusive processes dominate sediment entrainment; for steep ripples, flow separation occurs above the ripples creating vortices, which are far more efficient at entraining sediment into the water column. Recent laboratory experiments for mixtures of sand and mud have shown that bedform dimensions decrease with increasing sediment mud content. However, these same experiments also showed that mud is selectively taken into suspension when bedforms are created and migrate on the bed, leaving sandy bedforms. This entrainment process, selectively suspending fine sediment, is referred to as winnowing. To improve our understanding of bedform and entrainment dynamics of mixed sediments, in situ observations were made on intertidal flats in the Dee Estuary, United Kingdom. A suite of instruments were deployed collecting co-located measurements of the near-bed hydrodynamics, waves, small-scale bed morphology and suspended sediment. Three sites were occupied consecutively, over a Spring-Neap cycle, collecting data for different bed compositions, tide levels and wind conditions. Bed samples were taken when the flats became exposed at low water and a sediment trap collected suspended load when inundated. This study will combine these measurements to investigate the interactions between small-scale bed morphology, near-bed hydrodynamics and sediment entrainment. We will examine bedform development in the complex hydrodynamic and wave climate of tidal flats, in relation to standard ripple predictors. We will also relate the variability in small-scale bedforms to variation in hydrodynamic and wave conditions

  13. Enhanced Biotransformation of Fluoranthene by Intertidally Derived Cunninghamella elegans under Biofilm-Based and Niche-Mimicking Conditions

    Science.gov (United States)

    Mitra, Sayani; Pramanik, Arnab; Banerjee, Srijoni; Haldar, Saubhik; Gachhui, Ratan

    2013-01-01

    The aims of the investigation were to ascertain if surface attachment of Cunninghamella elegans and niche intertidal conditions provided in a bioreactor influenced biotransformation of fluoranthene by C. elegans. A newly designed polymethylmethacrylate (PMMA) conico-cylindrical flask (CCF) holding eight equidistantly spaced rectangular strips mounted radially on a circular disc allowed comparison of fluoranthene biotransformation between CCFs with a hydrophobic surface (PMMA-CCF) and a hydrophilic glass surface (GS-CCF) and a 500-ml Erlenmeyer flask (EF). Fluoranthene biotransformation was higher by 22-fold, biofilm growth was higher by 3-fold, and cytochrome P450 gene expression was higher by 2.1-fold when C. elegans was cultivated with 2% inoculum as biofilm culture in PMMA-CCF compared to planktonic culture in EF. Biotransformation was enhanced by 7-fold with 10% inoculum. The temporal pattern of biofilm progression based on three-channel fluorescence detection by confocal laser scanning microscopy demonstrated well-developed, stable biofilm with greater colocalization of fluoranthene within extracellular polymeric substances and filaments of the biofilm grown on PMMA in contrast to a glass surface. A bioreactor with discs rotating at 2 revolutions per day affording 6-hourly emersion and immersion mimicked the niche intertidal habitat of C. elegans and supported biofilm formation and transformation of fluoranthene. The amount of transformed metabolite was 3.5-fold, biofilm growth was 3-fold, and cytochrome P450 gene expression was 1.9-fold higher in the process mimicking the intertidal conditions than in a submerged process without disc rotation. In the CCF and reactor, where biofilm formation was comparatively greater, higher concentration of exopolysaccharides allowed increased mobilization of fluoranthene within the biofilm with consequential higher gene expression leading to enhanced volumetric productivity. PMID:24038685

  14. Abundance of non-native crabs in intertidal habitats of New England with natural and artificial structure.

    Science.gov (United States)

    Lovely, Christina M; O'Connor, Nancy J; Judge, Michael L

    2015-01-01

    Marine habitats containing complex physical structure (e.g., crevices) can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock) and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m(2) with 62 mm(2) mesh openings). The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width) whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1-15 mm carapace width), and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m(-2) [mean ± S.D.]) and fewest in bags without shells (4.9 ± 3.7 m(-2)). Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks). The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations.

  15. Abundance of non-native crabs in intertidal habitats of New England with natural and artificial structure

    Directory of Open Access Journals (Sweden)

    Christina M. Lovely

    2015-09-01

    Full Text Available Marine habitats containing complex physical structure (e.g., crevices can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m2 with 62 mm2 mesh openings. The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1–15 mm carapace width, and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m−2 [mean ± S.D.] and fewest in bags without shells (4.9 ± 3.7 m−2. Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks. The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations.

  16. Adaptive traits are maintained on steep selective gradients despite gene flow and hybridization in the intertidal zone.

    Directory of Open Access Journals (Sweden)

    Gerardo I Zardi

    Full Text Available Gene flow among hybridizing species with incomplete reproductive barriers blurs species boundaries, while selection under heterogeneous local ecological conditions or along strong gradients may counteract this tendency. Congeneric, externally-fertilizing fucoid brown algae occur as distinct morphotypes along intertidal exposure gradients despite gene flow. Combining analyses of genetic and phenotypic traits, we investigate the potential for physiological resilience to emersion stressors to act as an isolating mechanism in the face of gene flow. Along vertical exposure gradients in the intertidal zone of Northern Portugal and Northwest France, the mid-low shore species Fucus vesiculosus, the upper shore species Fucus spiralis, and an intermediate distinctive morphotype of F. spiralis var. platycarpus were morphologically characterized. Two diagnostic microsatellite loci recovered 3 genetic clusters consistent with prior morphological assignment. Phylogenetic analysis based on single nucleotide polymorphisms in 14 protein coding regions unambiguously resolved 3 clades; sympatric F. vesiculosus, F. spiralis, and the allopatric (in southern Iberia population of F. spiralis var. platycarpus. In contrast, the sympatric F. spiralis var. platycarpus (from Northern Portugal was distributed across the 3 clades, strongly suggesting hybridization/introgression with both other entities. Common garden experiments showed that physiological resilience following exposure to desiccation/heat stress differed significantly between the 3 sympatric genetic taxa; consistent with their respective vertical distribution on steep environmental clines in exposure time. Phylogenetic analyses indicate that F. spiralis var. platycarpus is a distinct entity in allopatry, but that extensive gene flow occurs with both higher and lower shore species in sympatry. Experimental results suggest that strong selection on physiological traits across steep intertidal exposure gradients

  17. Spatial and temporal variation of intertidal nematodes in the northern Gulf of Mexico after the Deepwater Horizon oil spill.

    Science.gov (United States)

    Brannock, Pamela M; Sharma, Jyotsna; Bik, Holly M; Thomas, W Kelley; Halanych, Kenneth M

    2017-09-01

    Nematodes are an abundant and diverse interstitial component of sedimentary habitats that have been reported to serve as important bioindicators. Though the 2010 Deepwater Horizon (DWH) disaster occurred 60 km offshore in the Gulf of Mexico (GOM) at a depth of 1525 m, oil rose to the surface and washed ashore, subjecting large segments of coastline in the northern GOM to contamination. Previous metabarcoding work shows intertidal nematode communities were negatively affected by the oil spill. Here we examine the subsequent recovery of nematode community structure at five sites along the Alabama coast over a two-year period. The latter part of the study (July 2011-July 2012) also included an examination of nematode vertical distribution in intertidal sediments. Results showed nematode composition within this region was more influenced by sample locality than time and depth. The five sampling sites were characterized by distinct nematode assemblages that varied by sampling dates. Nematode diversity decreased four months after the oil spill but increased after one year, returning to previous levels at all sites except Bayfront Park (BP). There was no significant difference among nematode assemblages in reference to vertical distribution. Although the composition of nematode assemblages changed, the feeding guilds they represented were not significantly different even though some variation was noted. Data from morphological observations integrated with metabarcoding data indicated similar spatial variation in nematode distribution patterns, indicating the potential of using these faster approaches to examine overall disturbance impact trends within communities. Heterogeneity of microhabitats in the intertidal zone indicates that future sampling and fine-scale studies of nematodes are needed to examine such anthropogenic effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Short Term CO2 Enrichment Increases Carbon Sequestration of Air-Exposed Intertidal Communities of a Coastal Lagoon

    Directory of Open Access Journals (Sweden)

    Amrit K. Mishra

    2018-01-01

    Full Text Available In situ production responses of air-exposed intertidal communities under CO2 enrichment are reported here for the first time. We assessed the short-term effects of CO2 on the light responses of the net community production (NCP and community respiration (CR of intertidal Z. noltei and unvegetated sediment communities of Ria Formosa lagoon, when exposed to air. NCP and CR were measured in situ in summer and winter, under present and CO2 enriched conditions using benthic chambers. Within chamber CO2 evolution measurements were carried out by a series of short-term incubations (30 min using an infra-red gas analyser. Liner regression models fitted to the NCP-irradiance responses were used to estimate the seasonal budgets of air-exposed, intertidal production as determined by the daily and seasonal variation of incident photosynthetic active radiation. High CO2 resulted in higher CO2 sequestration by both communities in both summer and winter seasons. Lower respiration rates of both communities under high CO2 further contributed to a potential negative climate feedback, except in winter when the CR of sediment community was higher. The light compensation points (LCP (light intensity where production equals respiration of Z. noltei and sediment communities also decreased under CO2 enriched conditions in both seasons. The seasonal community production of Z. noltei was 115.54 ± 7.58 g C m−2 season−1 in summer and 29.45 ± 4.04 g C m−2 season−1 in winter and of unvegetated sediment was 91.28 ± 6.32 g C m−2 season−1 in summer and 25.83 ± 4.01 g C m−2 season−1 in winter under CO2 enriched conditions. Future CO2 conditions may increase air-exposed seagrass production by about 1.5-fold and unvegetated sediments by about 1.2-fold.

  19. In situ oxygen dynamics and carbon turnover in an intertidal sediment (Skallingen, Denmark)

    DEFF Research Database (Denmark)

    Walpersdorf, Eva Christine; Kühl, Michael; Elberling, Bo

    2017-01-01

    /tidal cycles and to evaluate the importance of key drivers affecting the community performance. Time-series measurements of the oxygen (O2) microdistribution across 2 sites at a silty sandflat documented extreme variability, which was mainly driven by light availability and flow conditions. Diffusion dominated...... activity during the target autumn period was net heterotrophic with an average net ecosystem metabolism of −2.21 (span: −7.93 to 1.48) mmol O2 m−2 d−1. This study highlights the extreme temporal and spatial variation of intertidal sediments and the importance of accounting for natural in situ dynamics...

  20. Intertidal Sandbar Welding as a Primary Source of Sediment for Dune Growth: Evidence from a Large Scale Field Experiment

    Science.gov (United States)

    Cohn, N.; Ruggiero, P.; de Vries, S.

    2016-12-01

    Dunes provide the first line of defense from elevated water levels in low-lying coastal systems, limiting potentially major flooding, economic damages, and loss of livelihood. Despite the well documented importance of healthy dunes, our predictive ability of dune growth, particularly following erosive storm events, remains poor - resulting in part from traditionally studying the wet and dry beach as separate entities. In fact, however, dune recovery and growth is closely tied to the subtidal morphology and the nearshore hydrodynamic conditions, necessitating treating the entire coastal zone from the shoreface to the backshore as an integrated system. In this context, to further improve our understanding of the physical processes allowing for beach and dune growth during fair weather conditions, a large field experiment, the Sandbar-aEolian Dune EXchange EXperiment, was performed in summer 2016 in southwestern Washington, USA. Measurements of nearshore and atmospheric hydrodynamics, in-situ sediment transport, and morphology change provide insight into the time and space scales of nearshore-beach-dune exchanges along a rapidly prograding stretch of coast over a 6 week period. As part of this experiment, the hypothesis that dune growth is limited by the welding of intertidal sandbars to the shoreline (Houser, 2009) was tested. Using laser particle counters, bed elevation sensors (sonar altimeters and Microsoft Kinect), continuously logging sediment traps, RGB and IR cameras, and repeat morphology surveys (terrestrial lidar, kite based structure from motion, and RTK GPS), spatial and temporal trends in aeolian sediment transport were assessed in relation to the synoptic onshore migration and welding of intertidal sandbars. Observations from this experiment demonstrate that (1) the intertidal zone is the primary source of sediment to the dunes during non-storm conditions, (2) rates of saltation increase during later stages of bar welding but equivalent wind conditions

  1. Does acute led (Pb) contamination influence membrane fatty acid composition and freeze tolerance in intertidal blue mussels in arctic Greenland?

    DEFF Research Database (Denmark)

    Thyrring, Jakob; Juhl, Bodil Klein; Holmstrup, Martin

    2015-01-01

    In their natural habitats, organisms are exposed to multiple stressors. Heavy metal contamination stresses the cell membrane due to increased peroxidation of lipids. Likewise, sub-zero air temperatures potentially reduce membrane functionality in ectothermal animals. We tested if acute lead (Pb......) exposure for 7 days would influence survival in intertidal blue mussels (Mytilus edulis) after exposure to realistic sub-zero air temperatures. A full factorial experiment with five tissue Pb concentrations between 0 and 3500 lg Pb/g and six sub-zero temperatures from 0 to -17 °C were used to test...

  2. Radiocaesium, plutonium and americium partitioning and solid speciation in sized, inter-tidal sediments from Strangford Lough

    International Nuclear Information System (INIS)

    Ledgerwood, F.K.; Larmour, R.A.; Mitchell, P.I.; Leon Vintro, L.; Ryan, R.W.

    1999-01-01

    Fine-grained surface (0-2 cm) sediment was collected at an inter-tidal site (Mahee Island) in Strangford Lough, on the NE coast of Ireland in September 1997. The sediment was wet-sieved into standard sized fractions using Endecott test sieves and the fractions assayed for 137 Cs, 239,240 Pu and 241 Am content. Sub-samples of each fraction were measured with a Malvern 2600 laser diffraction analyser, which confirmed that >90% of the particles in each fraction was in the defined size range

  3. Check-list of interstitial polychaetes from intertidal and shallow subtidal soft bottoms of Tenerife, Canary Islands

    OpenAIRE

    Riera, Rodrigo; Núñez, Jorge; Carmen Brito, María del

    2010-01-01

    A check-list of polychaete species from two stations on the south coast of Tenerife (Los Abrigos and Los Cristianos) at two different tidal levels, intertidal and shallow subtidal (3 m depth) is presented. A total of 47 species were collected, the hesionid Microphthalmus pseudoaberrans Campoy & Viéitez, 1982 and the spionids Rhynchospio glutaea (Ehlers, 1897) and Spio filicornis (O.F. Müller, 1776) being the most abundant. With 18 species the family Syllidae is the most diverse, followed b...

  4. Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves

    Science.gov (United States)

    Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

    2009-01-01

    The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

  5. Maize, tropical (Zea mays L.).

    Science.gov (United States)

    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

  6. Effects of simulated oil exposure on two intertidal macrozoo benthos: Tympanotonus fuscata (L.) and Uca tangeri (Eydoux, 1935) in a tropical estuarine ecosystem.

    Science.gov (United States)

    Ewa-Oboho, I O; Abby-Kalio, N J

    1994-08-01

    The impacts of simulated Nigerian light crude oil on mud flat periwinkles, Tympanotonus fuscata (L.), and fiddler crabs, Uca tangeri (Eydoux, 1935) was examined through field experiments conducted in the Bonny estuary of the Niger Delta (southern Nigeria). The purpose was to assess the fate and effects of a known quantity of the Nigerian light crude oil on this environment. Drastic changes in the densities of T. fuscata and U. tangeri observed immediately after spills was attributed to the effects of the oil. A large increase in Uca biomass occurred in the affected area. Salinity and temperature in the study area showed little fluctuations throughout the survey. Sediment characteristics were similar for all sites (stations). Grain-size analysis revealed that sediments at the study area were 70% silt. Migration of oil via tidal percolation was observed as much as 11 cm beneath the sediment surface.

  7. Year 2001 Tropical Cyclones of the World

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Year 2001 Tropical Cyclones of the World poster. During calendar year 2001, fifty tropical cyclones with sustained surface winds of at least 64 knots were observed...

  8. Year 2000 Tropical Cyclones of the World

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Year 2000 Tropical Cyclones of the World poster. During calendar year 2000, forty-five tropical cyclones with sustained surface winds of at least 64 knots were...

  9. Archives: Tropical Journal of Pharmaceutical Research

    African Journals Online (AJOL)

    Items 1 - 50 of 97 ... Archives: Tropical Journal of Pharmaceutical Research. Journal Home > Archives: Tropical Journal of Pharmaceutical Research. Log in or Register to get access to full text downloads.

  10. Tropical rain forest: a wider perspective

    National Research Council Canada - National Science Library

    Goldsmith, F. B

    1998-01-01

    .... Barbier -- Can non-market values save the tropical forests? / D. Pearce -- The role of policy and institutions / James Mayers and Stephen Bass -- Modelling tropical land use change and deforestation...

  11. Habitat heterogeneity in the assemblages and shell use by the most abundant hermit crabs (Anomura: Diogenidae and Paguridae: does the occupied shell species differ according to gender and species?

    Directory of Open Access Journals (Sweden)

    Gilson Stanski

    Full Text Available Abstract The goal of this study was to identify patterns of shell occupation by different species of hermit crabs from the southern Brazilian coast. In total, 644 individuals were collected, represented by six hermit species. Isocheles sawayai Forest & Saint Laurent, 1968 showed the highest abundance, with 575 individuals, followed by Loxopagurus loxochelis (Moreira, 1901 (n = 56. The other species were Petrochirus diogenes (Linnaeus, 1758, Dardanus insignis (Saussure, 1858, Pagurus exilis (Benedict, 1892 and Pagurus leptonyx Forest & Saint Laurent, 1968. Loxopagurus loxochelis was found associated with shells of 12 gastropod species, with 75% of males occupying shells of Olivancilaria urceus (Roding, 1798 and 78% of females inhabiting shells of Semicassis granulata (Born, 1778. Shells of Semicassis granulata were the lightest of all gastropod shells, demonstrating differential resource utilization. Additionally, I. sawayai occupied shells of 10 species, highlighting Stramonita haemastoma (Linnaeus, 1767 with the highest occupation percentage in all demographic classes, confirming a pattern of occupation with a strong relationship to the availability of the resource. The comparison of our results with those of other studies corroborated the influence of region and gastropod diversity on gastropod shell occupation.

  12. Possible climatic impact of tropical deforestation

    Energy Technology Data Exchange (ETDEWEB)

    Potter, G L; Ellsaesser, H W; MacCracken, M C; Luther, F M

    1975-12-25

    A computer model of climate changes resulting from removal of tropical rain forests to increase arable acreage is described. A chain of consequences is deduced from the model which begins with deforestation and ends with overall global cooling and a reduction in precipitation. A model of the global water budget shows that the reduction in precipitation is accompanied by cooling in the upper tropical troposphere, a lowering of the tropical tropopause, and a warming of the lower tropical stratosphere. (HLW)

  13. Physiological responses in a variable environment: relationships between metabolism, hsp and thermotolerance in an intertidal-subtidal species.

    Directory of Open Access Journals (Sweden)

    Yun-wei Dong

    Full Text Available Physiological responses to temperature reflect the evolutionary adaptations of organisms to their thermal environment and the capability of animals to tolerate thermal stress. Contrary to conventional metabolism theory, increasing environmental temperatures have been shown to reduce metabolic rate in rocky-eulittoral-fringe species inhabiting highly variable environments, possibly as a strategy for energy conservation. To study the physiological adaptations of an intertidal-subtidal species to the extreme and unpredictable heat stress of the intertidal zone, oxygen consumption rate and heat shock protein expression were quantified in the sea cucumber Apostichopus japonicus. Using simulate natural temperatures, the relationship between temperature, physiological performance (oxygen consumption and heat shock proteins and thermotolerance were assessed. Depression of oxygen consumption rate and upregulation of heat shock protein genes (hsps occurred in sequence when ambient temperature was increased from 24 to 30°C. Large-scale mortality of the sea cucumber occurred when temperatures rose beyond 30°C, suggesting that the upregulation of heat shock proteins and mortality are closely related to the depression of aerobic metabolism, a phenomenon that is in line with the concept of oxygen- and capacity-limited thermal tolerance (OCLTT. The physiologically-related thermotolerance of this sea cucumber should be an adaptation to its local environment.

  14. Effects of habitat-forming species richness, evenness, identity, and abundance on benthic intertidal community establishment and productivity.

    Directory of Open Access Journals (Sweden)

    Julie Lemieux

    Full Text Available In a context of reduced global biodiversity, the potential impacts from the loss of habitat-forming species (HFS on ecosystem structure and functioning must be established. These species are often the main community primary producers and have a major role in the establishment of organisms through facilitation processes. This study focuses on macroalgae and mussels as HFS within an intertidal zone along the St. Lawrence estuary (Quebec, Canada. Over a 16-week period, we manipulated the in situ diversity profile (richness, evenness, identity, and abundance of the dominant HFS (Fucus distichus edentatus, F. vesiculosus, and Mytilus spp. in order to define their role in both the establishment of associated species and community primary production. Contrary to expectation, no general change in HFS richness, evenness, abundance, or identity on associated species community establishment was observed. However, over the study period, the HFS diversity profile modified the structure within the trophic guilds, which may potentially affect further community functions. Also, our results showed that the low abundance of HFS had a negative impact on the primary productivity of the community. Our results suggest that HFS diversity profiles have a limited short-term role in our study habitat and may indicate that biological forcing in these intertidal communities is less important than environmental conditions. As such, there was an opportunistic establishment of species that ensured rapid colonization regardless of the absence, or the diversity profile, of facilitators such as HFS.

  15. Restoration Effects of the Riparian Forest on the Intertidal Fish Fauna in an Urban Area of the Amazon River

    Science.gov (United States)

    Ferrari, Stephen F.; Vasconcelos, Huann C. G.; Mendes-Junior, Raimundo N. G.; Araújo, Andrea S.; Costa-Campos, Carlos Eduardo; Nascimento, Walace S.; Isaac, Victoria J.

    2016-01-01

    Urbanization causes environmental impacts that threaten the health of aquatic communities and alter their recovery patterns. In this study, we evaluated the diversity of intertidal fish in six areas affected by urbanization (areas with native vegetation, deforested areas, and areas in process of restoration of vegetation) along an urban waterfront in the Amazon River. 20 species were identified, representing 17 genera, 14 families, and 8 orders. The different degrees of habitat degradation had a major effect on the composition of the fish fauna; the two least affected sectors were the only ones in that all 20 species were found. Eight species were recorded in the most degraded areas. The analysis revealed two well-defined groups, coinciding with the sectors in better ecological quality and degraded areas, respectively. The native vegetation has been identified as the crucial factor to the recovery and homeostasis of the studied ecosystem, justifying its legal protection and its use in the restoration and conservation of altered and threatened environments. These results reinforce the importance of maintaining the native vegetation as well as its restoration in order to benefit of the fish populations in intertidal zones impacted by alterations resulting from inadequate urbanization. PMID:27699201

  16. Restoration Effects of the Riparian Forest on the Intertidal Fish Fauna in an Urban Area of the Amazon River

    Directory of Open Access Journals (Sweden)

    Júlio C. Sá-Oliveira

    2016-01-01

    Full Text Available Urbanization causes environmental impacts that threaten the health of aquatic communities and alter their recovery patterns. In this study, we evaluated the diversity of intertidal fish in six areas affected by urbanization (areas with native vegetation, deforested areas, and areas in process of restoration of vegetation along an urban waterfront in the Amazon River. 20 species were identified, representing 17 genera, 14 families, and 8 orders. The different degrees of habitat degradation had a major effect on the composition of the fish fauna; the two least affected sectors were the only ones in that all 20 species were found. Eight species were recorded in the most degraded areas. The analysis revealed two well-defined groups, coinciding with the sectors in better ecological quality and degraded areas, respectively. The native vegetation has been identified as the crucial factor to the recovery and homeostasis of the studied ecosystem, justifying its legal protection and its use in the restoration and conservation of altered and threatened environments. These results reinforce the importance of maintaining the native vegetation as well as its restoration in order to benefit of the fish populations in intertidal zones impacted by alterations resulting from inadequate urbanization.

  17. A NEW SAR CLASSIFICATION SCHEME FOR SEDIMENTS ON INTERTIDAL FLATS BASED ON MULTI-FREQUENCY POLARIMETRIC SAR IMAGERY

    Directory of Open Access Journals (Sweden)

    W. Wang

    2017-11-01

    Full Text Available We present a new classification scheme for muddy and sandy sediments on exposed intertidal flats, which is based on synthetic aperture radar (SAR data, and use ALOS-2 (L-band, Radarsat-2 (C-band and TerraSAR-X (X-band fully polarimetric SAR imagery to demonstrate its effectiveness. Four test sites on the German North Sea coast were chosen, which represent typical surface compositions of different sediments, vegetation, and habitats, and of which a large amount of SAR is used for our analyses. Both Freeman-Durden and Cloude-Pottier polarimetric decomposition are utilized, and an additional descriptor called Double-Bounce Eigenvalue Relative Difference (DERD is introduced into the feature sets instead of the original polarimetric intensity channels. The classification is conducted following Random Forest theory, and the results are verified using ground truth data from field campaigns and an existing classification based on optical imagery. In addition, the use of Kennaugh elements for classification purposes is demonstrated using both fully and dual-polarization multi-frequency and multi-temporal SAR data. Our results show that the proposed classification scheme can be applied for the discrimination of muddy and sandy sediments using L-, C-, and X-band SAR images, while SAR imagery acquired at short wavelengths (C- and X-band can also be used to detect more detailed features such as bivalve beds on intertidal flats.

  18. Environmental radiation and potential ecological risk levels in the intertidal zone of southern region of Tamil Nadu coast (HBRAs), India.

    Science.gov (United States)

    Punniyakotti, J; Ponnusamy, V

    2018-02-01

    Natural radioactivity content and heavy metal concentration in the intertidal zone sand samples from the southern region of Tamil Nadu coast, India, have been analyzed using gamma ray spectrometer and ICP-OES, respectively. From gamma spectral analysis, the average radioactivity contents of 238 U, 232 Th, and 40 K in the intertidal zone sand samples are 12.13±4.21, 59.03±4.26, and 197.03±26.24Bq/kg, respectively. The average radioactivity content of 232 Th alone is higher than the world average value. From the heavy metal analysis, the average Cd, Cr, Cu, Ni, Pb, and Zn concentrations are 3.1, 80.24, 82.84, 23.66, 91.67, and 137.07ppm, respectively. The average Cr and Ni concentrations are lower, whereas other four metal (Cd, Cu, Pb, and Zn) concentrations are higher than world surface rock average values. From pollution assessment parameter values, the pollution level is "uncontaminated to moderately contaminated" in the study area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Anti-oxidative feedback and biomarkers in the intertidal seagrass Zostera japonica induced by exposure to copper, lead and cadmium

    International Nuclear Information System (INIS)

    Lin, Haiying; Sun, Tao; Zhou, Yi; Zhang, Xiaomei

    2016-01-01

    To investigate the potential influences of anthropogenic pollutants, we evaluated the responses of the intertidal seagrass Zostera japonica to three heavy metals: copper (Cu), lead (Pb), and cadmium (Cd). Z. japonica was exposed to various concentrations of Cu, Pb , and Cd (0, 0.5, 5, 50 μM) over seven days. The effects were then analyzed using the antioxidant enzyme catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione peroxidase (GPX), and lipid peroxidation measured using malondialdehyde (MDA) as proxy. Metal accumulation in the above-ground tissues and phenotypic changes were also investigated. Our results revealed that heavy metal concentration increased in seagrass exposed to high levels of metals. Z. japonica has great potential for metal accumulation and a suitable candidate for the decontamination of moderately Cu contaminated bodies of water and can also potentially enhanced efforts of environmental decontamination, either through phytoextraction abilities or by functioning as an indicator for monitoring programs that use SOD, CAT, GPX, POD and MDA as biomarkers. - Highlights: • Anti-oxidative feedback of Zostera japonica to the heavy metals Cu, Pb, and Cd was determined. • The endangered intertidal seagrass Z. japonica had a high metal accumulation potential. • Z. japonica might be a potential indicator in monitoring programs using SOD, CAT, GPX, POD and MDA as biomarkers.

  20. Heavy metal pollution and Pb isotopic tracing in the intertidal surface sediments of Quanzhou Bay, southeast coast of China

    International Nuclear Information System (INIS)

    Yu, Ruilian; Zhang, Weifang; Hu, Gongren; Lin, Chengqi; Yang, Qiuli

    2016-01-01

    Concentrations of 16 heavy metals and Pb isotopic ratios in the intertidal surface sediments of Quanzhou Bay were determined to study the pollution level of heavy metals and the sources of Pb. The results showed that most concentrations of Cd, Sn, Mn, Cu, Zn, Cr, Pb, Hg, Ni, Co, Cs, Fe and V were higher than the background values, while most concentrations of Ti, Sb and Sr were lower than the background values. The mean concentrations of Cu, Zn, Pb, Cr and Cd exceeded the first-grade criteria of Chinese marine sediment quality. The geo-accumulation indexes revealed that the sediments had been polluted by some heavy metals. The results of Pb isotopic tracing indicated that the total Pb in the sediments were mainly from parent material, industrial emission and vehicle exhaust with the mean contributions of 38.2%, 51.3% and 10.5%, respectively, calculated by a three-end-member model of Pb isotopic ratios. - Highlights: •Level of 16 heavy metals in intertidal surface sediments of Quanzhou Bay was studied. •The sediments had been polluted by some heavy metals including Pb. •Pb isotopic compositions in the sediments and the potential sources were determined. •A three-end member model was applied to estimate the contributions of Pb sources. •Industrial emission was the major anthropogenic Pb contributor in the sediments.