3,233 research outputs found
High pCO 2 levels affect metabolic rate, but not feeding behavior and fitness, of farmed giant mussel Choromytilus chorus
Indexación: Scopus.Acknowledgements. We thank Luisa Saavedra and Araceli Rodriguez-Romero for their help in the field and during laboratory activities. We also acknowledge Laura Ramajo for help with AT estimations. Emily Giles Neill provided valuable comments that greatly improved the manuscript. Special thanks are due to the reviewers and the editor for very constructive comments on the manuscript. This study was supported by the Millennium Nucleus Center for the Study of Multiple drivers on Marine Socio-Ecological Systems (MUSELS) funded by MINECON NC120086, PIA CONICYT ACT-172037 and FONDECYT grant nos. 1140938 and 1140092 to N.A.L. and M.A.L.Mar Ecol Prog Ser 454: 65−74 Findlay HS, Wood HL, Kendall MA, Spicer JI, Twitchett RJ, Widdicombe S (2009) Calcification, a physiological pro-cess to be considered in the context of the whole organ-ism. Biogeosciences 6: 2267−2284 Fitzer SC, Zhu W, Tanner KE, Phoenix VR, Kamenos NA, Cusack M (2015) Ocean acidification alters the material properties of Mytilus edulis shells. J R Soc Interface 12: 214−227 Freitas R, De Marchi L, Bastos M, Moreira A and others (2017) Effects of seawater acidification and salinity alter-ations on metabolic, osmoregulation and oxidative stress markers in Mytilus galloprovincialis. Ecol Indic 79: 54−62 Gattuso JP, Magnan A, Billé R, Cheung WWL and others (2015) Contrasting futures for ocean and society from dif-ferent anthropogenic CO2 emissions scenarios. Science 349: aac4722 Gazeau F, Urbini L, Cox TE, Alliouane S, Gattuso JP (2015) Comparison of the alkalinity and calcium anomaly tech-niques to estimate rates of net calcification. Mar Ecol Prog Ser 527: 1−12 Gray MW, Langdon CJ, Waldbusser GG, Hales B, Kramer S (2017) Mechanistic understanding of ocean acidification impacts on larval feeding physiology and energy budg-ets of the mussel Mytilus californianus. Mar Ecol Prog Ser 563: 81−94 Griffiths CL, Griffiths RJ (1987) Animal energetics, Vol 2: Bivalvia through Reptilia. In: Pandian TJ, Vernberg FJ (eds) Bivalvia. Academic Press, New York, NY, p 1−88 Harvey BP, Dwynn-Jones D, Moore PJ (2013) Meta-analysis reveals complex marine biological responses to the inter-active effects of ocean acidification and warming. Ecol Evol 3: 1016−1030 Hiebenthal C, Philipp EER, Eisenhauer A, Wahl M (2013) Effects of seawater pCO2 and temperature on shell growth, shell stability, condition and cellular stress of western Baltic Sea Mytilus edulis (L.) and Arctica is - landica (L.). Mar Biol 160: 2073−2087 Ibarrola I, Arambalza U, Navarro JM, Urrutia MB, Navarro E (2012) Allometric relationships in feeding and diges-tion in the Chilean mytilids Mytilus chilensis (Hupé), Choromytilus chorus (Molina) and Aulacomya ater (Mo - lina): a comparative study. J Exp Mar Biol Ecol 426-427: 18−27 Lagos NA, Benítez S, Duarte C, Lardies MA and others (2016) Effects of temperature and ocean acidification on shell characteristics of Argopecten purpuratus: implica-tions for scallop aquaculture in an upwelling-influenced area. Aquacult Environ Interact 8: 357−370 Lardies MA, Arias MB, Poupin MJ, Manríquez PH and oth-ers (2014) Differential response to ocean acidification in physiological traits of Concholepas concholepas popula-tions. J Sea Res 90: 127−134 Lardies MA, Benítez S, Osores S, Vargas CA, Duarte C, Lohrmann KB, Lagos NA (2017) Physiological and histo - pathological impacts of increased carbon dioxide and temperature on the scallops Argopecten purpuratus cultured under upwelling influences in northern Chile. Aquaculture 479: 455−466 Lemasson AJ, Fletcher S, Hall-Spencer JM, Knights AM (2017) Linking the biological impacts of ocean acidifica-tion on oysters to changes in ecosystem services: a review. J Exp Mar Biol Ecol 492: 49−62 Mackenzie CL, Ormondroyd GA, Curling SF, Ball RJ, Whitely NM, Malham SK (2014) Ocean warming, more than acidification, reduces shell strength in a commercial shellfish species during food limitation. PLOS ONE 9: e86764 McElhany P (2017) CO2 sensitivity experiments are not suf-ficient to show an effect of ocean acidification. ICES J Mar Sci 74: 926−928 Mehrbach C, Culberson CH, Hawley JE, Pytkowicz RM (1973) Measurement of the apparent dissociation con-stants of carbonic acid in seawater at atmospheric pres-sure. Limnol Oceanogr 18: 897−907 Melzner F, Thomsen J, Koeve W, Oschlies A and others (2013) Future ocean acidification will be amplified by hypoxia in coastal habitats. Mar Biol 160: 1875−1888 Michaelidis B, Ouzounis C, Paleras A, Pörtner HO (2005) Effects of long-term moderate hypercapnia on acid−base balance and growth rate in marine mussels Mytilus gal-loprovincialis. Mar Ecol Prog Ser 293: 109−118 Miller AW, Reynolds AC, Sobrino C, Riedel GF (2009) Shell-fish face uncertain future in high CO2 world: influence of acidification on oyster larvae calcification and growth in estuaries. PLOS ONE 4: e5661 Navarro JM (1988) The effects of salinity on the physio - logical ecology of Choromytilus chorus (Molina, 1782) (Bivalvia: Mytilidae). J Exp Mar Biol Ecol 122: 19−33 Navarro JM, Torres R, Acuña K, Duarte C and others (2013) Impact of medium-term exposure to elevated pCO2 lev-els on the physiological energetics of the mussel Mytilus chilensis. Chemosphere 90: 1242−1248 Navarro JM, Duarte C, Manríquez PH, Lardies MA and oth-ers (2016) Ocean warming and elevated carbon dioxide: multiple stressor impacts on juvenile mussels from south-ern Chile. ICES J Mar Sci 73: 764−771 Nienhuis S, Palmer AR, Harley CD (2010) Elevated CO2 affects shell dissolution rate but not calcification rate in a marine snail. Proc R Soc B 277: 2553−2558 Orr JC, Fabry VJ, Aumont O, Bopp L and others (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437: 681−686 Osores SJ, Lagos NA, San Martin V, Manríquez PH and others (2017) Plasticity and inter-population variability in physiological and life-history traits of the mussel Mytilus chilensis: a reciprocal transplant experiment. J Exp Mar Biol Ecol 490: 1−12 Palmer AR (1982) Growth in marine gastropods: a non-destructive technique for independently measuring shell and body weight. Malacologia 23: 63−73 Parker LM, Ross PM, O’Connor WA, Borysko L, Raftos DA, Pörtner HO (2012) Adult exposure influences offspring response to ocean acidification in oysters. Glob Change Biol 18: 82−92 Pierrot D, Lewis E, Wallace DWR (2006) MS Excel program developed for CO2 system calculations. ORNL/CDIAC-105a. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, TN Ramajo L, Marba N, Prado L, Peron S and others (2016) Bio-mineralization changes with food supply confer juvenile scallops (Argopecten purpuratus) resistance to ocean acidification. Glob Change Biol 22: 2025−2037 Range P, Chícharo MA, Ben-Hamadou R, Piló D and others (2014) Impacts of CO2-induced seawater acidification on coastal Mediterranean bivalves and interactions with other climatic stressors. Reg Environ Change 14(Suppl 1): 19−30 Sabine C, Feely RA, Gruber N, Key RM and others (2004) The oceanic sink of anthropogenic CO2. Science 305: 367–371 SERNAPESCA (Servicio Nacional de Pesca y Acuicultura) (2014) Anuarios estadísticos del Servicio Nacional de Pesca y Acuicultura. www.sernapesca.cl Solórzano L (1969) Determination of ammonia in natural waters by the phenolhypochlorite method. Limnol Oce - anogr 14: 799−801 Thomsen J, Melzner F (2010) Moderate seawater acidifica-tion does not elicit long-term metabolic depression in the blue mussel Mytilus edulis. Mar Biol 157: 2667−2676 Thomsen J, Casties I, Pansch C, Körtzinger A, Melzner F (2013) Food availability outweighs ocean acidification effects in juvenile Mytilus edulis: laboratory and field experiments. Glob Change Biol 19: 1017−1027 Thomsen J, Stapp LS, Haynert K, Schade H, Danelli M, Lannig G, Melzner F (2017) Naturally acidified habitat selects for ocean acidification-tolerant mussels. Sci Adv 3: e1602411 Toro B, Navarro JM, Palma-Fleming H (2003) Relationship between bioenergetics responses and organic pollutants in the giant mussel, Choromytilus chorus (Mollusca: Mytilidae). Aquat Toxicol 63: 257−269 Torres R, Pantoja S, Harada N, González HE, Daneri G, Frangopulos M, Fukasawa M (2011) Air-sea CO2 fluxes along the coast of Chile: from CO2 outgassing in central northern upwelling waters to CO2 uptake in southern Patagonian fjords. J Geophys Res 116: C09006 Torres R, Manriquez PH, Duarte C, Navarro JM, Lagos NA, Vargas CA, Lardies MA (2013) Evaluation of a semi - automatic system for long-term seawater carbonate chemistry manipulation. Rev Chil Hist Nat 86: 443−451 Vargas CA, Aguilera V, Martín V, Manríquez P and others (2015) CO2-driven ocean acidification disrupts the filter feeding behavior in Chilean gastropod and bivalve spe-cies from different geographic localities. Estuaries Coasts 38: 1163−1177 Vargas CA, Lagos NA, Lardies MA, Duarte C and others (2017) Species-specific responses to ocean acidification should account for local adaptation and adaptive plasti-city. Nature Ecol Evol 1: 0084 Vargas CA, Cuevas LA, Silva N, Gonzalez HE, Pol-Holz D, Narvaez DA (2018) Influence of glacier melting and river discharges on the nutrient distribution and DIC recycling in the southern Chilean Patagonia. J Geophys Res Bio-geosci 123: 256−270 Velasco LA, Navarro JM (2003) Energetic balance of infau-nal (Mulinia edulis King, 1831) and epifaunal (Mytilus chilensis Hupé, 1854) bivalves in response to wide varia-tions in concentration and quality of seston. J Exp Mar Biol Ecol 296: 79−92 Vihtakari M, Hendriks IE, Holding J, Renaud PE, Duarte CM, Havenhand JN (2013) Effects of ocean acidification and warming on sperm activity and early life stages of the Mediterranean mussel (Mytilus galloprovincialis). Water 5: 1890−1915 Wang Y, Li L, Hu M, Lu W (2015) Physiological energetic of the thick shell mussel Mytilus coruscus exposed to sea-water acidification and thermal stress. Sci Total Environ 514: 261−272 White MM, McCorkle DC, Mullineaux LS, Cohen AL (2013)Benthic habitats such as intertidal areas, sandy or rocky shores, upwelling zones, and estuaries are characterized by variable environmental conditions. This high variability of environmental stressors such as temperature, salinity, and pH/pCO 2 levels have been shown to impose restrictions on organismal performance. The giant mussel Choromytilus chorus forms intertidal and subtidal mussel beds in estuarine zones associated with fjords occurring in southern Chile and is an important aquacultural resource in Patagonia. In this study, we estimated the sensitivity of physiological traits and energy balance of C. chorus juveniles exposed to 3 pCO 2 treatments (500, 750, and 1200 μatm) for 30 d. Results showed that in acidified, high pCO 2 conditions, C. chorus juveniles had increased metabolic rates; however, other physiological traits (clearance and ingestion rates, ammonia excretion, absorption efficiency, growth rate, biomass production, net calcification, and dissolution rates) were not affected. These results suggest that when subjected to acidification, the adaptive response of C. chorus triggers tradeoffs among physiological traits that favor sustained feeding and growth in order to combat increased metabolic stress. As has been reported for other marine organisms, chronic exposure to variable pH/pCO 2 in their native habitats, such as estuarine zones, could explain the differential acclimatization capacity of giant mussels to cope with the increase in pCO 2 . Additionally, the fact that the mussels did not suffer from mortality indicates that increased pCO 2 levels may have chronic, but not lethal, effects on this species under these experimental conditions. © The authors 2017.https://www.int-res.com/abstracts/aei/v10/p267-278
Statistics of counter-streaming solar wind suprathermal electrons at solar minimum : STEREO observations
Previous work has shown that solar wind suprathermal electrons can display a number of features in terms of their anisotropy. Of importance is the occurrence of counter-streaming electron patterns, i.e., with "beams" both parallel and anti-parallel to the local magnetic field, which is believed to shed light on the heliospheric magnetic field topology. In the present study, we use STEREO data to obtain the statistical properties of counter-streaming suprathermal electrons (CSEs) in the vicinity of corotating interaction regions (CIRs) during the period March–December 2007. Because this period corresponds to a minimum of solar activity, the results are unrelated to the sampling of large-scale coronal mass ejections, which can lead to CSE owing to their closed magnetic field topology. The present study statistically confirms that CSEs are primarily the result of suprathermal electron leakage from the compressed CIR into the upstream regions with the combined occurrence of halo depletion at 90° pitch angle. The occurrence rate of CSE is found to be about 15–20% on average during the period analyzed (depending on the criteria used), but superposed epoch analysis demonstrates that CSEs are preferentially observed both before and after the passage of the stream interface (with peak occurrence rate >35% in the trailing high speed stream), as well as both inside and outside CIRs. The results quantitatively show that CSEs are common in the solar wind during solar minimum, but yet they suggest that such distributions would be much more common if pitch angle scattering were absent. We further argue that (1) the formation of shocks contributes to the occurrence of enhanced counter-streaming sunward-directed fluxes, but does not appear to be a necessary condition, and (2) that the presence of small-scale transients with closed-field topologies likely also contributes to the occurrence of counter-streaming patterns, but only in the slow solar wind prior to CIRs
Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean
This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the Soufrière Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features
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Intermittent release of transients in the slow solar wind: 2. In situ evidence
In paper 1, we showed that the Heliospheric Imager (HI) instruments on the pair of NASA STEREO spacecraft can be used to image the streamer belt and, in particular, the variability of the slow solar wind which originates near helmet streamers. The observation of intense intermittent transient outflow by HI implies that the corresponding in situ observations of the slow solar wind and corotating interaction regions (CIRs) should contain many signatures of transients. In the present paper, we compare the HI observations with in situ measurements from the STEREO and ACE spacecraft. Analysis of the solar wind ion, magnetic field, and suprathermal electron flux measurements from
the STEREO spacecraft reveals the presence of both closed and partially disconnected interplanetary magnetic field lines permeating the slow solar wind. We predict that one of the transients embedded within the second CIR (CIR‐D in paper 1) should impact the near‐Earth ACE spacecraft. ACE measurements confirm the presence of a transient at the time of CIR passage; the transient signature includes helical magnetic fields and bidirectional suprathermal electrons. On the same day, a strahl electron dropout is observed at STEREO‐B, correlated with the passage of a high plasma beta structure. Unlike ACE, STEREO‐B observes the transient a few hours ahead of the CIR. STEREO‐A, STEREO‐B, and ACE spacecraft observe very different slow solar wind properties ahead of and during the CIR analyzed in this paper, which we associate with the intermittent release of transients
Transport properties of copper phthalocyanine based organic electronic devices
Ambipolar charge carrier transport in Copper phthalocyanine (CuPc) is studied
experimentally in field-effect transistors and metal-insulator-semiconductor
diodes at various temperatures. The electronic structure and the transport
properties of CuPc attached to leads are calculated using density functional
theory and scattering theory at the non-equilibrium Green's function level. We
discuss, in particular, the electronic structure of CuPc molecules attached to
gold chains in different geometries to mimic the different experimental setups.
The combined experimental and theoretical analysis explains the dependence of
the mobilityand the transmission coefficient on the charge carrier type
(electrons or holes) and on the contact geometry. We demonstrate the
correspondence between our experimental results on thick films and our
theoretical studies of single molecule contacts. Preliminary results for
fluorinated CuPc are discussed.Comment: 18 pages, 16 figures; to be published in Eur. Phys. J. Special Topic
From bi-layer to tri-layer Fe nanoislands on Cu3Au(001)
Self assembly on suitably chosen substrates is a well exploited root to
control the structure and morphology, hence magnetization, of metal films. In
particular, the Cu3Au(001) surface has been recently singled out as a good
template to grow high spin Fe phases, due to the close matching between the
Cu3Au lattice constant (3.75 Angstrom) and the equilibrium lattice constant for
fcc ferromagnetic Fe (3.65 Angstrom). Growth proceeds almost layer by layer at
room temperature, with a small amount of Au segregation in the early stage of
deposition. Islands of 1-2 nm lateral size and double layer height are formed
when 1 monolayer of Fe is deposited on Cu3Au(001) at low temperature. We used
the PhotoElectron Diffraction technique to investigate the atomic structure and
chemical composition of these nanoislands just after the deposition at 140 K
and after annealing at 400 K. We show that only bi-layer islands are formed at
low temperature, without any surface segregation. After annealing, the Fe atoms
are re-aggregated to form mainly tri-layer islands. Surface segregation is
shown to be inhibited also after the annealing process. The implications for
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Pulmonary Hypertension in Patients with Chronic Fibrosing Idiopathic Interstitial Pneumonias
Background Pulmonary hypertension (PH) is a common finding in patients with chronic fibrosing idiopathic interstitial pneumonias (IIP). Little is known about the response to pulmonary vasodilator therapy in this patient population. COMPERA is an international registry that prospectively captures data from patients with various forms of PH receiving pulmonary vasodilator therapies. Methods We retrieved data from COMPERA to compare patient characteristics, treatment patterns, response to therapy and survival in newly diagnosed patients with idiopathic pulmonary arterial hypertension (IPAH) and PH associated with IIP (PH-IIP). Results Compared to patients with IPAH (n = 798), patients with PH-IIP (n = 151) were older and predominantly males. Patients with PH-IIP were treated predominantly with phosphodiesterase-5 inhibitors (88% at entry, 87% after 1 year). From baseline to the first follow-up visit, the median improvement in 6MWD was 30 m in patients with IPAH and 24.5 m in patients with PH-IIP (p = 0.457 for the difference between both groups). Improvements in NYHA functional class were observed in 22.4% and 29.5% of these patients, respectively (p = 0.179 for the difference between both groups). Survival rates were significantly worse in PH-IIP than in IPAH (3-year survival 34.0 versus 68.6%; p<0.001). Total lung capacity, NYHA class IV, and mixed-venous oxygen saturation were independent predictors of survival in patients with PH-IIP. Conclusions Patients with PH-IIP have a dismal prognosis. Our results suggest that pulmonary vasodilator therapy may be associated with short-term functional improvement in some of these patients but it is unclear whether this treatment affects survival
Searching for Binary Y Dwarfs with the Gemini Multi-Conjugate Adaptive Optics System (GeMS)
The NASA Wide-field Infrared Survey Explorer (WISE) has discovered almost all the known members of the new class of Y-type brown dwarfs. Most of these Y dwarfs have been identified as isolated objects in the field. It is known that binaries with L- and T-type brown dwarf primaries are less prevalent than either M-dwarf or solar-type primaries, they tend to have smaller separations and are more frequently detected in near-equal mass configurations. The binary statistics for Y-type brown dwarfs, however, are sparse, and so it is unclear if the same trends that hold for L- and T-type brown dwarfs also hold for Y-type ones. In addition, the detection of binary companions to very cool Y dwarfs may well be the best means available for discovering even colder objects. We present results for binary properties of a sample of five WISE Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System. We find no evidence for binary companions in these data, which suggests these systems are not equal-luminosity (or equal-mass) binaries with separations larger than ~0.5–1.9 AU. For equal-mass binaries at an age of 5 Gyr, we find that the binary binding energies ruled out by our observations (i.e., 10^(42) erg) are consistent with those observed in previous studies of hotter ultra-cool dwarfs
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